Articles de revues : « Micro-Attentions »

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Luo, Liang, Zheng Yi Jiang, Dong Bin Wei et Xiaofeng He. « Study on Micro Hydroforming of Metals ». Advanced Materials Research 887-888 (février 2014) : 1133–38. http://dx.doi.org/10.4028/www.scientific.net/amr.887-888.1133.

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Micro hydroforming has an ability to manufacture complex 3D micro parts at a high production rate and has drawn increasing attentions. Brief understanding of macro hydroforming, for instance, deep drawing, is necessary to understand the principle of micro hydroforming. Then, special phenomena, such as size effects, occurred at micro scale are discussed and the related theories explaining these phenomena are introduced. Based on the similarities and differences between micro and macro hydroforming, experiments and simulation which consider the size effects are reviewed.

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Takalkar, Madhumita A., Selvarajah Thuseethan, Sutharshan Rajasegarar, Zenon Chaczko, Min Xu et John Yearwood. « LGAttNet : Automatic micro-expression detection using dual-stream local and global attentions ». Knowledge-Based Systems 212 (janvier 2021) : 106566. http://dx.doi.org/10.1016/j.knosys.2020.106566.

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Huang, Bo Wun, Jung Ge Tseng et Chien Hua Chang. « Finite Element Analysis on Vibration of a Piezoelectric Micro Pump ». Applied Mechanics and Materials 789-790 (septembre 2015) : 861–64. http://dx.doi.org/10.4028/www.scientific.net/amm.789-790.861.

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Due to the rise of biological and MEMS technology in recent years, some micro flow system components have been paid attentions to developed by many investigators. The importance of micro-pumps manufactured is higher than the other part of micro flow system since it is the power source of the entire micro-flow system and responsible for driving working fluid in the microfluidic system. In actual operation, the instability and bad dynamic characteristics of the micro-pump will cause larger fluid flow mobility error, such as transport behavior and response procedures failure, etc., and even damage the microfluidic system. Therefore, to investigate the stability and dynamic characteristics of a micro pump is necessary. The miniature piezoelectric film micro-pump, made by Microjet Technology Co., Ltd., is employed to study in this work. The computer graphics software SolidWorks is used to build the model of the micro pump. Then, The Finite element analysis (FEA), ANSYS Workbench, is also employed to analyze the dynamic characteristics of this micro pump.

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Liu, Ting Ting, Wei Su, Tao Yang, Bin Han et Chao Wang. « Research on Characteristics of Mercury Droplet Flow in Micro Acceleration Switch ». Key Engineering Materials 562-565 (juillet 2013) : 328–33. http://dx.doi.org/10.4028/www.scientific.net/kem.562-565.328.

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Unlike the solid-solid contact of traditional micro acceleration switch, liquid metal can be utilized to solve the disadvantage of solid-solid contact, such as contact wear and signal bounce. Liquid-metal micro switches have demonstrated no contact bounce, low switch-on time, low contact resistance, long life, and the capability to handle large currents. So the liquid-metal micro acceleration switches have attracted researcher’s attentions increasingly. To investigate the flow characteristics of mercury droplet in micro acceleration switch, this paper establishes numerical models of micro acceleration switch by using FLUENT. The effect of contact angle, droplet volume and temperature are discussed in this paper. Based on the VOF-CSF model of FLUENT, a serial of simulations were performed. The simulation results show that the influence of contact angle and droplet volume on flow characteristics is serious, and the influence of temperature is small. As compared with theoretical analysis, simulations are in good agreement with theoretical analysis.

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Luo, Yuehao, Robert Smith et Lork Green. « Exploring instantaneous micro-imprinting technology on semi-cured epoxy resin coating based on relationship between forming precision and curing degree ». Chemical Industry and Chemical Engineering Quarterly 22, n^o 1 (2016) : 47–53. http://dx.doi.org/10.2298/ciceq150119018l.

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Nano/micro-imprinting technology base on polymer material coating has attracted the increasing attentions throughout the world in the past several decades, and it is progressively developing into the hot topic at present, in which, how to improve the manufacturing efficiency is becoming the urgent issue to be resolved. Polymer?s curing process is exactly complicated and sophisticated, which involves simultaneously performing physical and chemical changes, when the curing reaction reaches certain level, the system will abruptly transform into insoluble, non-melting gel with rapidly increased viscosity and rigidity, which can generate fixed deformation under persistent external pressure. In this paper, the plastic deformation capacity of epoxy resin in the curing process is investigated by the micro-dimple imprinting experiment, and the relationship between forming precision and curing degree is ascertained adopting the DSC (differential scanning calorimetry) method. In addition, the instantaneous micro-imprinting technology based on the micro-grooves is explored, and the experimental results indicate that the forming precision can surpass 90%. The paper will establish a novel avenue to apply the nano/micro imprinting technology into practical engineering.

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Keighobadi, J., J. Faraji et S. Rafatnia. « Chaos Control of Atomic Force Microscope System Using Nonlinear Model Predictive Control ». Journal of Mechanics 33, n^o 3 (13 septembre 2016) : 405–15. http://dx.doi.org/10.1017/jmech.2016.89.

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AbstractOwing to robust and optimal specification, model predictive control method has received wide attentions over recent years. Since in certain operational conditions, an Atomic/scanning Force Microscope (AFM) shows chaos behavior, the chaos feedback control of the AFM system is considered. According to the nonlinear model of forces interacting between the tip of micro cantilever and the substrate of AFM; the nonlinear control methods are proposed. In the paper, the chaos control of a micro cantilever AFM based on the nonlinear model predictive control (NMPC) technique is presented. Through software simulation results, the effectiveness of the designed NMPC of the AFM is assessed. The simulation results together with analytical stability proofs indicate that the proposed method is effective in keeping the system in a stable range.

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Luo, Liang, Zheng Yi Jiang, Dong Bin Wei, Hideki Sato, Tsuyoshi Furushima et Ken-Ichi Manabe. « A Numerical Study of Micro Hydro Deep Drawing of SUS304 Sheets ». Applied Mechanics and Materials 846 (juillet 2016) : 524–29. http://dx.doi.org/10.4028/www.scientific.net/amm.846.524.

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Micro forming is a promising technology and has drawn global attentions due to the urgent requirements on miniaturised products. Micro hydro deep drawing (MHDD) is a typical micro forming method and its products are widely applied in various fields, such as micro electro-mechanical systems (MEMS), medical and aerospace areas. However, tiny sizes of both products and tools are obstacles to investigate this novel technology. Therefore, finite element method (FEM) is adopted and modified to study the influence of processing parameters on micro drawing process and produced products. In this study, a normal hydro deep drawing model was developed, and then a voronoi blank model was generated to consider the size effects of materials. Additionally, a surface layer model was created based on the voronoi blank model. Therefore, the open and closed lubricant theory can be fulfilled and friction behaviour in MHDD can be considered. Subsequently, different processing parameters, such as hydraulic pressure and material inhomogeneity, were investigated. Simulation results indicate that a proper hydraulic pressure improves drawability and shape accuracy of the drawn cups. Moreover, material inhomogeneity affects the quality of drawn cups.

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Wang, Jingjing, Baozheng Xu, Yinfang Zhu et Junyuan Zhao. « Microcantilever sensors for biochemical detection ». Journal of Semiconductors 44, n^o 2 (1 février 2023) : 023105. http://dx.doi.org/10.1088/1674-4926/44/2/023105.

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Abstract Microcantilever is one of the most popular miniaturized structures in micro-electromechanical systems (MEMS). Sensors based on microcantilever are ideal for biochemical detection, since they have high sensitivity, high throughput, good specification, fast response, thus have attracted extensive attentions. A number of devices that are based on static deflections or shifts of resonant frequency of the cantilevers responding to analyte attachment have been demonstrated. This review comprehensively presents state of art of microcantilever sensors working in gaseous and aqueous environments and highlights the challenges and opportunities of microcantilever biochemical sensors.

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Yang, Wenqing, Liguang Wang et Bifeng Song. « Dove : A biomimetic flapping-wing micro air vehicle ». International Journal of Micro Air Vehicles 10, n^o 1 (9 octobre 2017) : 70–84. http://dx.doi.org/10.1177/1756829317734837.

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This paper describes the design and development of the Dove, a flapping-wing micro air vehicle (FWMAV), which was developed in Northwestern Polytechnical University. FWMAVs have attracted international attentions since the past two decades. Since some achievements have been obtained, such as the capability of supporting an air vehicle to fly, our research goal was to design an FWMAV that has the ability to accomplish a task. Main investigations were presented in this paper, including the flexible wing design, the flapping mechanism design, and the on-board avionics development. The current Dove has a mass of 220 g, a wingspan of 50 cm, and the ability of operating fully autonomously, flying lasts half an hour, and transmitting live stabilized color video to a ground station over 4 km away.

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Zhang, Xiao Quan, et L. Tian. « Three-Dimensional Simulation of Micro Air Vehicles with Low-Aspect-Ratio Wings ». Key Engineering Materials 339 (mai 2007) : 377–81. http://dx.doi.org/10.4028/www.scientific.net/kem.339.377.

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Micro Air Vehicles (MAVs) are catching more and more attentions for their broad application in civilian and military fields. Since the theories on the aerodynamics of low Reynolds number are not maturely presented and the wind-tunnel experiments cost long periods and great expenses. The numerical simulation based on computational fluid dynamics (CFD) is a good method to choose. Through three-dimensional simulation of the wings, the aerodynamic characteristics of the flows around MAVs can be easily obtained. The tip vortices produced around low-Reynolds-number and low-aspect-ratio wings can increase the lift and stall angles. The result of numerical simulation can be used as references of theory analysis and wind-tunnel experiments.

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Liu, Zhong-Peng, Si-Nan Song et Mu Zhang. « Facile Fabrication of Fluorine-Free Superhydrophobic Surfaces with SiO2 Monospheres ». Journal of Nanoelectronics and Optoelectronics 16, n^o 2 (1 février 2021) : 208–12. http://dx.doi.org/10.1166/jno.2021.2934.

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Recently, superhydrophobic surface on various type of substrates have attracted much attentions in electronics field. In this work, the classic Stöber method was used to prepare spherical silica particles with different particle sizes by adding different amounts of electrolyte (potassium chloride), giving rise to size distribution ranging from 300 nm to 2.55 yitm. Herein we constructed a micro-nano lotus-like structure in a facile way, achieving a superhydrophobic surface with using any Fluorine related chemicals. In the sense, the silica particles modified with HMDS were sprayed to prepare hydrophobic surface with contact angle up to 152.96° by increasing the frequency of sprays.

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Xu, Yanping, et Xiaoyi Bao. « Micro-structured fibers and their applications in fiber-optic sensors and random fiber lasers ». Canadian Journal of Physics 96, n^o 4 (avril 2018) : 359–65. http://dx.doi.org/10.1139/cjp-2017-0304.

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Micro-structured fibers are important devices that have drawn intensive attentions and proved to be powerful platforms for various applications over the past decades due to their remarkable merits and advantages, such as small footprint, immunity to electromagnetic interferences, light weight, high physical flexibility, and low cost. Modifications in optical fibers can be used as light-steering elements to excite and couple back different core and cladding modes and form various in-fiber structures, including in-line fiber interferometer, fiber micro-cantilever, fiber random gratings, and so on. These micro-structures, when applied as fiber-optic sensors in the presence of external disturbances, show high sensitivity in terms of the significant changes in the guided light features. Novel micro-structured bend-insensitive fiber-based in-line fiber interferometer and micro-cantilever have been proposed to realize both static and dynamic parameter measurements, including temperature, axial strain, surrounding refractive index, and vibration. We have also developed a novel fiber random grating along with a spectral correlation algorithm for simultaneous measurement of three static measurands. To move a step forward, random fiber lasers based on fiber random grating are achieved for either improving the laser performances or sensing applications of temperature, strain, and ultrasound measurements with high sensitivity.

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Qiao, Ling, Tao Han, Hong Tao Wang, Lai Hui Han et Shi Wei Gu. « Microscopic Study on Mechanical Properties of Different Microregions during In-Service Welding ». Materials Science Forum 944 (janvier 2019) : 841–53. http://dx.doi.org/10.4028/www.scientific.net/msf.944.841.

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In-service welding has been gaining considerable attentions due to its significant economic benefits. At high temperature, several technical difficulties exist during repair process and burn-through has been one of the critical issues. To reveal the physical nature of burn-through, finite element simulation and molecular dynamics simulation are combined to investigate the micro dynamic properties of different micro regions in welded joint and the effect of crack on the microdynamic behavior in the process of material failure. The results indicate that burn-through is a failure process under the effect of tensile stress and high temperature. The performance near fusion line is the worst and a burn-through tends to occur at the regions behind maximum melting depth. The failure process of welded joints experience the initiation and development of micro defects. Continuous expansion of micro holes and micro cracks causes the structural fracture. Furthermore, the micro crack would decrease the structural strength and the failure mode differs for cracks in different direction. Failure process of crack structure has experienced the crack tip passivation and dislocation emission. And the formation of stacking fault is carried out in failure process. This paper reveals the microscopic mechanism of burn-through at the atomic level and provides a scientific basis for the continuous and safe operation of gas pipelines.

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Chen, Kan, Pei Dong Zhu et Yue Shan Xiong. « Measuring the Use of Real-Name Policy in Micro-Blogging of China ». Applied Mechanics and Materials 519-520 (février 2014) : 257–61. http://dx.doi.org/10.4028/www.scientific.net/amm.519-520.257.

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Real-name policy has been adopted in some specific fields of China for several years. As the leading micro-blogging service of China, Weibo has introduced the real name policy in 2012. However, the question is that how the real-name policy is used is still unknown. In this paper, with a dataset of 158,979 accounts crawled from Weibo, we conduct a deep measurement and analysis on the use of real-name policy. We find that although the rule has been promoted for several years, the proportion of verified users is still small. Our work also shows that famous people tend to use their real names to gain more public attentions. And a verified user is more likely to be followed by others.

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Zhang, Ruihan, Qiang Lu et Hanqing Zhao. « The learnable CPG model based on Wilson-Cowan oscillator ». Journal of Physics : Conference Series 2632, n^o 1 (1 novembre 2023) : 012003. http://dx.doi.org/10.1088/1742-6596/2632/1/012003.

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Abstract The central pattern generator (CPG) is a micro circuit in neural system and it can generate rhythmic signals to regulate locomotion. The researchers have investigated the features of the CPG, and they have paid more attentions to the the programmable characteristic. In this address, a new learnable CPG based on Wilson-Cowan oscillator is established. The sine signal, the complex signal, the chaotic signal and angles of compass-like robot are used as input to test the new programmable central pattern generator. The simulations present that the learnable CPG has the ability to learn different signals effectively. These results are the significant contribution to the research of the programmable CPG.

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Kang, Chun Mao, Jin Yan Ji, Jun Li Zhao, Hong Peng Zhong, Jiao He, Yu Ma et Mu Huo Yu. « Facile Fabrication of Super-Hydrophobic Surface on Aluminum and its Effects in Accelerating Underwater Bubble Bursting ». Materials Science Forum 789 (avril 2014) : 154–56. http://dx.doi.org/10.4028/www.scientific.net/msf.789.154.

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Facile fabrication of bio-mimic super-hydrophobic surfaces has attracted attentions in both fundamental research and practical application. In this article, we developed a simple one step etching method to fabricate a super-hydrophobic surface on aluminum surface. The contact angel of water reaches 155.9° without coating any low energy materials. Surface morphology clearly demonstrates a combination of micro/nanohierarchical structures. Moreover, such surface remarkably shortens the bursting time of air bubbles under water. For a middle size bubble about 1mm, the bursting time at super-hydrophobic surface shortens to about 20%, comparing to freely bursting. This intriguing effect may contribute to future expand applications of super-hydrophobic surface in industrial field, such as fiber spinning.

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Yan, Ting Ting, Si Yu Wu, Qing Hua Chen, Qing Mei Liu et Jia Rong Yang. « A Novel Biodegradable Phosphate Coating on AZ31B Alloy ». Applied Mechanics and Materials 707 (décembre 2014) : 158–62. http://dx.doi.org/10.4028/www.scientific.net/amm.707.158.

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Mg and its alloys draw more and more attentions to be used as biodegradable medical materials. But the rapid degradation of those materials limits their clinical applications. In this article, a phosphate coating was prepared on AZ31B magnesium alloy to improve its anti-corrosion property. Morphology, composition and corrosion resistance of the coating were studied. The SEM research showed that the coating that composed of rod-like phosphates with small amount of random distributed micro-voids was approximately10-20μm in thickness. The XRD analysis indicated that the coating was mainly composed of MgO, Mg3(PO4)2and Zn3(PO4)2·xH2O. Electrochemical test showed the phosphate treatment could significant improve the corrosion resistance of AZ31B.

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Li, Xiao Peng, Hui Fan Nie, Zhi Jie Zhao et Gui Qiu Song. « Review and Prospect of the Research of Vibration and Friction Mechanism of Machine Joint Surfaces ». Applied Mechanics and Materials 121-126 (octobre 2011) : 3487–92. http://dx.doi.org/10.4028/www.scientific.net/amm.121-126.3487.

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The machine joint surfaces are necessary to form the functions of the complex mechanical system. Because the macro or micro relative motions may appear in the machine joint surfaces, the vibration and friction phenomena will be excited, then the singularities, disturbances and faults of the mechanical system may be appeared when the machine equipments in the running process. These undesired phenomena will have adverse effect on the efficiency, precision, reliability and lifetime of the mechanical equipment. In order to ensure the functions and properties of the mechanical system, more attentions should be paid to mechanism of vibration and friction during the process of designing and manufacturing the modern machine. In this paper, machine joint surfaces are classified by different classification standards: the macro relative motions and micro contact styles between the joint surfaces. The theories and methods for researching vibration and friction mechanism are inducted and summarized and the view of non-linear should be advocated for the future research. The point of precisely quantifying for machine assembly accuracy design while considered the relevancies between the macro and micro-scale of mechanical system indicates that new directions and methods for studying vibration and friction mechanism in machine joint surfaces should be put forward.

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Shao, Zhen Wei, Zi Wei Xu, Xiu Yun Zhang, Gui Wu Liu, Hao Hua Li et Guan Jun Qiao. « Formation Mechanisms of the Point Defects from the 4H-SiC (0001) Surface to the Interior Layers : First Principle Calculation ». Key Engineering Materials 697 (juillet 2016) : 771–76. http://dx.doi.org/10.4028/www.scientific.net/kem.697.771.

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With the extended applications of hexagonal silicon carbide (h-SiC) in the various fields, particularly in the application of the electronic devices, more and more attentions have been focused on the micro structures as well as their physical properties of h-SiC surface. In this study, we have performed the first principal calculations to compare the formation energies of four typical defects (Vc, Vsi, CI and SiI) on the 4H-SiC (0001) surface as well as in the interior layers. Due to the surface reconstruction and the reduced lattice constrain, the optimized structures of the defects on/near the 4H-SiC (0001) surface are quite different from the ones in the deeper layers. The distinguished formation energies as function of chemical potential indicate that we may control the defects concentrations in different layers by tuning the environmental conditions. This theoretical work provides a significant understanding to the formation mechanism of the point defects on the 4H-SiC surface, and paves a way to the modification of the SiC surface via electron irradiation or ion implantation with micro-defects introduced.

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Han, Liang, Jing Song Jin et Wei Zhang. « A Conceptual Design of a Measuring System of Tennis Batting Motion Attitude Based on MEMS Sensors ». Applied Mechanics and Materials 198-199 (septembre 2012) : 1053–56. http://dx.doi.org/10.4028/www.scientific.net/amm.198-199.1053.

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Tennis is a very elegant sport, with a strong sense of competitiveness and appreciation, which has gained more and more attentions in our country, and it tends to be a fashion. This project is to achieve the measurement of tennis batting motion attitude in three dimensional space using a combination of the three-axis MEMS(Micro-electromechanical Systems) sensors, and make research on the principle of measurement system, composition and data acquisition. Body posture measurement system is to measure the attitude measurement in human movement, it can be applied to study the movement posture or to meet the requirements of position control, which provides theoretical foundation for scientific training and prevention of sports injury and also plays a significant and instructional role in improving the training levels of tennis playing and generalizing nationwide fitness campaign.

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Wu, Chang Fu. « Analysis and Realization of Critical Points on Hardware Design of FPGA ». Advanced Materials Research 950 (juin 2014) : 133–38. http://dx.doi.org/10.4028/www.scientific.net/amr.950.133.

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FPGA is one kind of important devices that can realize many functions. As the development of communication technology and computer science, more and more technologies are invented and more and more hardware design technologies are sifted out. Therefore, the hardware design based on ASIC can be not fit on the new theories realization. As a new device, FPGA has many advantages including strength function, shorter design circle, less money, more flexible and more intelligent design tools. More and More hardware designs of FPGA are pay more attentions. Therefore, it is significant to make analysis on hardware design of FPGA. The hardware design for FPGA will be related to the FPGA device. In the market Altera and Xilinx FPGAs are used frequently by engineers. Therefore, in this dissertation will be make analysis and realization the critical points in hardware design based on Xilinx FPGA. In this dissertation, the critical point of Hardware Design of FPGA will be described. It will include power source, impedance matching and clock circuit design. There are many hardware design tools used for hardware design including Altium Designer, Protel, Cadence and others. Compared with other design tools, Cadence will have more advantages. Therefore, in this dissertation, Cadence will be used as the design tool for hardware design analysis and realization. With the help of Cadence, one hardware design and signal transmission simulation will be made analysis. With the development of the micro-electronics technology and computer science, the hardware design about FPGA will be taken more and more attentions.

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Xie, Xiaofan, Yunfei Li, Gong Wang, Zhenxu Bai, Yu Yu, Yulei Wang, Yu Ding et Zhiwei Lu. « Femtosecond Laser Processing Technology for Anti-Reflection Surfaces of Hard Materials ». Micromachines 13, n^o 7 (8 juillet 2022) : 1084. http://dx.doi.org/10.3390/mi13071084.

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The anti-reflection properties of hard material surfaces are of great significance in the fields of infrared imaging, optoelectronic devices, and aerospace. Femtosecond laser processing has drawn a lot of attentions in the field of optics as an innovative, efficient, and green micro-nano processing method. The anti-reflection surface prepared on hard materials by femtosecond laser processing technology has good anti-reflection properties under a broad spectrum with all angles, effectively suppresses reflection, and improves light transmittance/absorption. In this review, the recent advances on femtosecond laser processing of anti-reflection surfaces on hard materials are summarized. The principle of anti-reflection structure and the selection of anti-reflection materials in different applications are elaborated upon. Finally, the limitations and challenges of the current anti-reflection surface are discussed, and the future development trend of the anti-reflection surface are prospected.

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Sheikh, Irfan Ahmed. « Prospects for Interest-Free Micro Finance in India : An Empirical Study ». Journal of Islamic Economic and Business Research 1, n^o 1 (14 juin 2021) : 15–39. http://dx.doi.org/10.18196/jiebr.v1i1.11578.

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Despite the growth of Islamic banking and finance, in recent times due attention were given to the issue of Islamic microfinance. It is so because, as per various estimates over two billion people across globe are still living in a miserable poverty which is a global challenge and India not being an exception. Since the Poverty remains, a continuous challenge throughout the human history so as the efforts to overcome poverty. Among various efforts a conventional micro finance a “new model” received global recognition and a hope. But even if successful stories in bringing development and eradicating poverty by small credit tool to poor and by gaining growing attentions by world bank , still millennium development goal remains unachieved. The critics’ remains not only restricted to, in reaching all forms of poor rather high unbearable interest rates and avoidance by Muslims due to interest are on debate. As an alternative, Islamic finance has its operations both in Islamic and Non-Islamic countries along Islamic Micro finance. It is so because Islamic microfinance programs are complement to Islamic banking, both in ideological and in practical terms. Although IMF is still in infancy stage even though growing rapidly. Various experiments either on individual level or group level are mostly practicing Islamic micro credit products. But Islamic micro crediting has not been yet formally reached to people for India. Therefore this study aims to investigate the prospects based on determinants. The target population has been taken a potential benifacries of interest free micro finance. The paper adopts a Quantifiable approach as a Questionnaire distributed in paper format based on stratified sampling with 602 as final responses. The findings shows that in general the community is cognizant of the various terms used in Interest free microfinance but in respects of products/services existing by Islamic microfinance institutes, it indicates the level of awareness is very low.

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Zhou, Xiang Ming, Reza Madanipour et Seyed Ghaffar. « Impact Properties of Hemp Fibre Reinforced Cementitious Composites ». Key Engineering Materials 711 (septembre 2016) : 163–70. http://dx.doi.org/10.4028/www.scientific.net/kem.711.163.

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The construction industry has seen an incredibly fast increase in utilizing natural fibres for making low-cost building materials to achieve sustainable construction. One of such applications is natural fibre-reinforced cementitious materials for either structural or non-structural purpose. Impact properties are engineering properties received increasing attentions from engineering community for structural materials. This research therefore studies impact resistance of hemp fibre reinforced cementitious composites at early ages. Hemp fibre with various lengths, 10 mm and 20 mm, are utilized to reinforce cementitious materials. Hemp fibre reinforced cementitious composite slabs were tested under repeating dropping mass till failure at the age of 7, 14 and 28 days. Cracking behaviour, impact resistance, absorbed impact energy and survived impact blows upon failure are qualitatively/quantitatively analysed. It has been found that 20 mm-long hemp fibre reinforcement leads to higher impact resistance, more absorbed impact energy and survived more impact blows upon failure. Cementitious composite slabs reinforced by 20 mm-long hemp fibres exhibit higher impact crack resistance ratio than those reinforced by 10 mm-long fibres. Longer fibres are more effective in inhibiting the growth of micro-cracks and blunting the propagation of micro-cracks before they join up to form macro cracks leading to ultimate failure.

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Guo, Lei, Guang Li et Zhilin Gan. « Effects of surface roughness on CMAS corrosion behavior for thermal barrier coating applications ». Journal of Advanced Ceramics 10, n^o 3 (1 mars 2021) : 472–81. http://dx.doi.org/10.1007/s40145-020-0449-7.

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AbstractCalcium-magnesium-alumina-silicate (CMAS) corrosion is an important cause for thermal barrier coating (TBC) failure, which has attracted increased attentions. In this study, some thermal barrier coating (TBC) materials including YSZ (yttria partially stabilized zirconia), GdPO4, and LaPO4 were prepared into bulks, and the effects of their surface roughness on wettability and spreading characteristics of molten CMAS were investigated. As-fabricated and polished bulks with different surface roughness were exposed to CMAS corrosion at 1250 °C for 1 and 4 h, following by macro and micro observations. Results revealed that compared with the as-fabricated bulks, molten CMAS on the polished samples had lower wettability and a smaller spreading area, mainly attributable to the reduced capillary force to drive the melt spreading. Meanwhile, GdPO4 and LaPO4 bulks exhibited lower CMAS wettability than YSZ bulk. It is thus considered that reducing the surface roughness is beneficial to CMAS corrosion resistance of TBCs.

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Fukuda, Toshio, et Hidemi Hosokai. « Special Issue on Micro-Machine ». Journal of Robotics and Mechatronics 3, n^o 1 (20 février 1991) : 1. http://dx.doi.org/10.20965/jrm.1991.p0001.

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Much attention has been paid to the micronization of machine systems founded on the silicon-based semiconductor technology which are greatly different imagewise from the conventional machines. As a result, studies are being actively carried out on micro-machines. In addition, studies on extremely micro actuators and sensors based on the conventional precision processing techniques are also being conducted. These techniques have begun to support studies and developments of micro-robots which are based on new concepts of machine systems. The following techniques may be contained in the basic technology of micro-robots: 1) Micro-mechanical device techniques; 2) Micro-sensor and control circuit techniques; 3) Systems techniques; 4) Measurement and evaluation techniques A micro-robot as the totally integrated system of these techniques is considered for use in various fields including medical treatments and industrial areas. For applications in the medical field, micro-robots may be used in microsurgery, micro-operation, and micro-capsuling, while for industrial applications, micro-robots may be employed in the areas of maintenance, manufacturing, public well-being, and construction, among others. Nevertheless, in order to develop components in the truly micro-mechanical realm, to further refine these techniques and then to complete a micro-robot, system components such as sensors, actuators, processors, energy sources, functional parts, and communications devices are essential. Recently, the techniques for precision processing of silicon have made remarkable progress; in consequence, close attentions are being paid to micro-machining whereby silicon substrates are processed cubically by means of these processing techniques to form cubically structured function al elements. Micro-machining enables surfaces to be processed without producing scratches, thereby making it possible to create mechanical elements having wide dynamic ranges. Micro-processors and micro-actuators enjoying these advantages are beginning to be created on silicon substrates. Against this background, the present special issue on micro-machine systems has been planned to provide a glance at how the micro-related technology in micromachines and micro-mechanisms has advanced thus far and also at what course the future development of this technology will follow or how it will affect the surrounding areas of the technology. In the beginning, discussions on micro-mechanisms, micro-sensors, and micro-actuators were provided by Dr. Teru Hayashi (Tokyo Institute of Technology), Osamu Tabata and Susumu Sugiyama (Toyoda Central Research Center, Inc.), Kohji Kajimura (Electrotechnical Laboratory), and Toshi Takamori (Kobe University). In the subsequent sections, Dr. Masayoshi Ezashi (Tohoku University), Toshio Fukuda, Motohiro Fujiyoshi, Fumihiro Arai, Hideo Matsuura (all of Nagoya University), Toshiro Higuchi (University of Tokyo), Minoru Sakata, Katsumi Hosoya, Masatoshi Oba, Masao Hirano (all of OMRON Corp.), Katsuyoshi Kuribayashi (Yamaguchi University), Yoshitaka Tatsue and Tokio Kitahara (both of Mechanical Engineering Laboratory) gave explanatory introductions of their research activities. At the same time, Dr. Kohji Ikuta (Kyushu Institute of Technology), Kinji Harada and Hideki Kuwayama (both of Yokogawa Electric Corp.) provided the news concerning the developments of their micro-machines. Moreover, the latest information on micro-machines was presented by Dr. Tadashi Kitamura and Mochimitsu Komori (both of Kyushu Institute of Technology). 1 hope you will find some useful articles for understanding the state of art and the direction of the future developments.

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Khan, Akhtar, et Kalipada Maity. « Parametric Optimization of Some Non-Conventional Machining Processes Using MOORA Method ». International Journal of Engineering Research in Africa 20 (octobre 2015) : 19–40. http://dx.doi.org/10.4028/www.scientific.net/jera.20.19.

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Non-conventional manufacturing techniques are most widely used in industries in order to achieve high accuracy and desirable product quality. Therefore, the selection of an appropriate machining parameter has become a crucial job before starting the operation. Several optimization methods are available to resolve the upstairs situation. The current study explores a novel technique namely multi-objective optimization on the basis of ratio analysis (MOORA) to solve different multi-objective problems that are encountered in the real-time manufacturing industries. This study focuses on the application of MOORA method for solving some non-conventional machining processes that have multiple criteria problems. Wire-Electric Discharge Machining (WEDM), Plasma Arc Cutting (PAC), Electro Chemical Micro Machining (ECMM), Electro Chemical Machining (ECM), Abrasive Jet Machining (AJM), Abrasive Water Jet Machining (AWJM), Ultrasonic Machining (USM), Laser Beam Machining (LBM) and Laser cutting process are the major attentions in the current study. Total nine NTM multi-criteria problems which include selection of proper machining parameters have been studied. The optimal settings of input variables obtained by using MOORA method nearly tie with those derived by the earlier investigators.

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Zhang, Huiling, Ruping Liu, Huiqing Zhao, Zhicheng Sun, Zilong Liu, Liang He et Ye Li. « Research Progress of Biomimetic Memristor Flexible Synapse ». Coatings 12, n^o 1 (25 décembre 2021) : 21. http://dx.doi.org/10.3390/coatings12010021.

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With the development of the Internet of things, artificial intelligence, and wearable devices, massive amounts of data are generated and need to be processed. High standards are required to store and analyze this information. In the face of the explosive growth of information, the memory used in data storage and processing faces great challenges. Among many types of memories, memristors have received extensive attentions due to their low energy consumption, strong tolerance, simple structure, and strong miniaturization. However, they still face many problems, especially in the application of artificial bionic synapses, which call for higher requirements in the mechanical properties of the device. The progress of integrated circuit and micro-processing manufacturing technology has greatly promoted development of the flexible memristor. The use of a flexible memristor to simulate nerve synapses will provide new methods for neural network computing and bionic sensing systems. In this paper, the materials and structure of the flexible memristor are summarized and discussed, and the latest configuration and new materials are described. In addition, this paper will focus on its application in artificial bionic synapses and discuss the challenges and development direction of flexible memristors from this perspective.

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Hu, Yusheng, Ziyun Yu, Genlian Fan, Zhanqiu Tan, Jiandang Zhou, Hao Zhang, Zhiqiang Li et Di Zhang. « Simultaneous enhancement of strength and ductility with nano dispersoids in nano and ultrafine grain metals : a brief review ». REVIEWS ON ADVANCED MATERIALS SCIENCE 59, n^o 1 (12 août 2020) : 352–60. http://dx.doi.org/10.1515/rams-2020-0028.

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AbstractGrain refinement is the most universal and effective method of strengthening metallic materials, which is known as the “Hall-Petch” relationship. However, when grain size is refined to sub-micro regime (Ultrafine Grain, UFG) or even nano regime (Nano Grain, NG), the plasticity of metallic materials becomes poor. Massive studies indicate that the low strain hardening ability resulted from the enhanced dynamic recovery and lack of dislocation accumulation in fine grains is the main reason for low ductility in UFG/NG metals. To resolve this “strength-ductility” conflict, different strategies have been taken, like bimodal/multimodal structure, nanotwins, gradient structure and intragranular nano dispersoids. Among them, the introduction of nano dispersoids into the fine grains attracted lots of attention due to its wide applicability and great success in simultaneously increasing the strength and ductility of the UFG/NG metal. In addition to the enhanced mechanical performance, the introduced second-phase particle may also bring some extraordinary functional properties into the metallic material. In this paper, a brief view of the strategies to improve ductility of the UFG/NG metals and the relevant toughening mechanisms are revealed. Special attentions are paid to the utilization of intragranular nano dispersoids in Aluminum alloys.

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Zemedu, Chaluma, et Wubshet Ibrahim. « Analysis of Non-Linear on the House Convection Stream of Couple Stress Micro-Polar Nano-Fluids Past Vertical Cone with Non-Fourier’s Heat and Non-Fick’s Mass Fluxes ». Journal of Nanofluids 12, n^o 4 (1 mai 2023) : 919–29. http://dx.doi.org/10.1166/jon.2023.1938.

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The main goal of this study is to analyze the effects of different governing parameters such as buoyancy forces, and thermal relaxation time parameter in non-linear convection flow on the combined two fluids couple stress and micro-polar nano-fluid over a vertical cone with non-isothermal surface with heat and mass transfer with non-Fourier’s heat and non-Fick’s Mass fluxes numerically. The mathematical modeling for the stream difficulty has been made with fitting similarity transformation by non-dimension variable. Major non-linear boundary value difficulties were hooked on combined high regulates non-linear ordinary differential equations. The significance of constraints on velocities, thermal and solutal profiles are evaluated and revealed through the graphs and tables. The convergence test has been maintained; on behalf of spots number larger than apposite web, the meticulousness isn’t influenced. The novelty of the study lies in the analysis on combined two fluids with different constitutive equations over a cone with non-isothermal surface which has little attentions. Findings indicate that enlarging the values of couple stress parameter A permit boost to characteristic measure polarity of fluid that decline velocity profile k′(α), Nusselt, and Sherwood numbers (H′ (0), p′ (0)), but it upsurges angular velocity l (α), skin friction coefficient and wall pair stress.

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Lanquetin, J. P., et S. Tchukriel. « L’impact de l’informel dans le travail infirmier en psychiatrie ». European Psychiatry 29, S3 (novembre 2014) : 646. http://dx.doi.org/10.1016/j.eurpsy.2014.09.010.

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Cette recherche en soins vise à identifier, nommer, qualifier et surtout caractériser les fonctions de l’informel dans le soin infirmier en psychiatrie, particulièrement dans l’écart entre soins programmés et soins non programmés. Il s’agit alors d’objectiver les savoirs faire mobilisés, mais aussi leurs impacts et leurs spécificités. Les objectifs de cette recherche en soins infirmiers (RSI) sont mobilisés sur trois niveaux d’investigations : en direction du patient, du professionnel et de l’équipe.Cette recherche multicentrique a connu sa phase d’enquêtes de terrain auprès d’équipes de soins d’unités d’hospitalisation temps plein de quatre établissements de la région Rhône Alpes, établissements représentatifs de l’offre de soins publique sectorisée. Les enquêtes ont allié trois outils d’investigation : des « entretiens semi-dirigés », des séquences « d’observations participantes périphériques » et des « dialogues en interaction avec l’action ». Le traitement de ces données de terrain a abouti à la détermination de 3100 unités d’actions en lien avec l’informel.Nous nous appuyons dans nos axes théoriques sur les apports et les invariants structuraux de la psychothérapie institutionnelle, de la psychodynamique du travail ainsi que de la praxéologie. Les résultats se présentent sous une triple forme. Tout d’abord, le cœur de la recherche avec la caractérisation de 139 fonctions en lien avec l’informel dans les soins, puis l’approche quantitative de ces données qualitatives (variable de lieux, de temps, de sites, etc.) et enfin le dégagement d’invariants opératoires, pour les caractéristiques communes à tous les sites investigués.Cette recherche et ses résultats sont en mesure d’établir sur des données valides, bien des zones invisibles et peu lisibles du travail institutionnel et des savoirs infirmier en psychiatrie. La caractérisation de ces attentions, de ces « micro-actes » et « micro-interventions » concourent à un « prendre soin » individuel et collectif, participent d’un climat relationnel, ouvrent à des espaces transitionnels ou se déploient aussi bien des actions de cognition sociales que les différentes dimensions de la proxémie, de l’empathie et du « care ».

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Jawad, Muhammad. « Insinuation of Arrhenius Energy and Solar Radiation on Electrical Conducting Williamson Nano Fluids Flow with Swimming Microorganism : Completion of Buongiorno's Model ». East European Journal of Physics, n^o 1 (2 mars 2023) : 135–45. http://dx.doi.org/10.26565/2312-4334-2023-1-17.

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The enriched thermal mechanisms and progressive of nanomaterial has enthused scientists to give devotion to this area in current days. The versatile and synthesizing utilization of such particles embrace energy production, solar systems, heating and cooling monitoring processes, renewable energy systems, cancer treatments, hybrid-powered motors and Nano electronics. Furthermore, in this era of biotechnology and bioengineering, the bio convection of Nano fluids provides for some enthralling applications, such as enzymes, biosensors and biofuels. With such magnetic applications and attentions. A mathematical model is presented for evaluating the electrical conducting Williamson nano fluid with heat and mass transfer over a porous stretched sheet in the existence of bioconvection. The bioconvection of swimming microorganisms, thermal radiation,thermal conductivity and Arrhenius energy are new facets of this investigation. The higher order non-linear governing partial differential equations (PDEs) are solved by applying appropriate similarity variables and resulting couple of ordinary differential equations (ODEs) is produced. The developing set of ODEs is solved numerically by utilizing well known shooting technique with ND solve command in Wolfram MATHEMATICA and compare the result with pvb4c code in MATLAB. The graphs for different physical quantities of interest together with non-dimension velocity, temperature, concentration and density of micro-organisms profiles are discovered for involving parameters like .magnetic parameter, Brownian motion, Rayleigh number, Peclet number, Bioconvective Lewis number, parameter of thermophoresis and buoyancy ratio parameter. The influence of numerous parameters on flow and heat transfer characteristics are debated.

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Liu, Shuyang, Baojiang Sun, Jianchun Xu, Hangyu Li et Xiaopu Wang. « Study on Competitive Adsorption and Displacing Properties of CO2 Enhanced Shale Gas Recovery : Advances and Challenges ». Geofluids 2020 (23 décembre 2020) : 1–15. http://dx.doi.org/10.1155/2020/6657995.

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CO2 enhanced shale gas recovery (CO2-ESGR) draws worldwide attentions in recent years with having significant environmental benefit of CO2 geological storage and economic benefit of shale gas production. This paper is aimed at reviewing the state of experiment and model studies on gas adsorption, competitive adsorption of CO2/CH4, and displacement of CO2-CH4 in shale in the process of CO2-ESGR and pointing out the related challenges and opportunities. Gas adsorption mechanism in shale, influencing factors (organic matter content, kerogen type, thermal maturity, inorganic compositions, moisture, and micro/nano-scale pore), and adsorption models are described in this work. The competitive adsorption mechanisms are qualitatively ascertained by analysis of unique molecular and supercritical properties of CO2 and the interaction of CO2 with shale matrix. Shale matrix shows a stronger affinity with CO2, and thus, adsorption capacity of CO2 is larger than that of CH4 even with the coexistence of CO2-CH4 mixture. Displacement experiments of CO2-CH4 in shale proved that shale gas recovery is enhanced by the competitive adsorption of CO2 to CH4. Although the competitive adsorption mechanism is preliminary revealed, some challenges still exist. Competitive adsorption behavior is not fully understood in the coexistence of CO2 and CH4 components, and more experiment and model studies on adsorption of CO2-CH4 mixtures need to be conducted under field conditions. Coupling of competitive adsorption with displacing flow is key factor for CO2-ESGR but not comprehensively studied. More displacement experiments of CO2-CH4 in shale are required for revealing the mechanism of flow and transport of gas in CO2-ESGR.

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Wang, Yuedan, Rong Yan, Quanwei Shi, Zhicheng Wang, Yanhong Yuan, Hong Cheng, Suping Li, Yubo Fan, Fengyuan Zhuang et Kesheng Dai. « Effects of microgravity and hypergravity on platelet functions ». Thrombosis and Haemostasis 101, n^o 05 (2009) : 902–10. http://dx.doi.org/10.1160/th08-11-0750.

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SummaryMany serious thrombotic and haemorrhagic diseases or fatalities have been documented in human being exposed to micro-gravity or hypergravity environments, such as crewmen in space, roller coaster riders, and aircrew subjected to high-G training. Some possible related organs have been examined to explore the mechanisms underlying these gravity change-related diseases. However, the role of platelets which are the primary players in both thrombosis and haemostasis is unknown. Here we show that platelet aggregation induced by ristocetin or collagen and platelet adhesion to von Willebrand factor (VWF) were significantly decreased after platelets were exposed to simulated microgravity. Conversely, these platelet functions were increased after platelets were exposed to hypergravity. The tail bleeding time in vivo was significantly shortened in mice exposed to high-G force, whereas, was prolonged in hindlimb unloaded mice. Furthermore, three of 23 mice died after 15 minutes of –8 Gx stress. Platelet thrombi disseminated in the heart ventricle and blood vessels in the brain, lung, and heart from the dead mice. Finally, glycoprotein (GP) Ibα surface expression and its association with the cytoskeleton were significantly decreased in platelets exposed to simulated microgravity, and obviously increased in hypergravity-exposed platelets. These data indicate that the platelet functions are inhibited in microgravity environments, and activated under high-G conditions, suggesting a novel mechanism for gravity change-related haemorrhagic and thrombotic diseases. This mechanism has important implications for preventing and treating gravity change-related diseases, and also suggests that special attentions should be paid to human actions under different gravity conditions.

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Tao, Zhi, Weidong Fang, Haiwang Li, Yi Huang, Tiantong Xu, Hanxiao Wu et Murun Li. « Hydrophobicity induced drag reduction : Perspectives from the slip length ». Journal of Applied Physics 133, n^o 5 (7 février 2023) : 054701. http://dx.doi.org/10.1063/5.0141310.

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Hydrophobicity has been developed in many areas, whose potentials in drag reduction at microscale have attracted numerous attentions for expanding the practical applications in fields of on chip devices, materials synthesis, and enhanced heat transfer. In this article, we select polydimethylsiloxane (PDMS) as the base material, whose hydrophobic modifications have been well developed. Among them, hydrofluoric acid treated one shows great performance and leads us to two types of microchannels, the straight and U-shaped, with enhanced hydrophobicity (from 91° to 106°). The coefficients of the pressure drop are experimentally measured with the Reynolds number ranging from 0 to 300. The results illustrate that the drag reduction rate reaches at 37.8% for the straight microchannel and 26.8% for the U-shaped microchannel. With the increase in the Reynolds number, the drag reduction effect stays almost constant for the straight channel, while it decreases gradually for the U-shaped channel. The flow impingement induced by a centrifugal force has an important impact on the slip effect that grows with the Re. Next, we adopt the numerical method and the micro-particle imaging velocimetry measurement to analyze the drag reduction effect from perspectives of the slip length. We successfully derive the slip length model correlating the drag reduction effect. Our results not only achieve substantial drag reduction in PDMS microchannels, but also provide a quantitative correlation between hydrophobicity and drag reduction, offering a feasible strategy for extensive applications at microscale, such as fluid actuation, bio-chip analysis, and highly efficient cooling system.

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Pebrianti, Dwi, Wong Jack Kee, Luhur Bayuaji et Achmad Solichin. « Navigating Urban Skies : Obstacle Avoidance Strategies for Quadrotor MAVs ». Journal of Physics : Conference Series 2866, n^o 1 (1 octobre 2024) : 012039. http://dx.doi.org/10.1088/1742-6596/2866/1/012039.

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Abstract Micro Aerial Vehicles (MAVs) has gained attentions since more than two decades ago starting from the applications in air combat up to civil applications such as packet deliveries, environmental monitoring, and surveillance. In an environment such as cities that grows denser, navigation and control for drones becomes challenging to ensure safe navigation around buildings and other obstacles. This study proposes an approach for obstacle avoidance for MAVs by using ultrasonic sensors. Four sensors are strategically positioned to cover the front, right, back, and left directions. Additionally, a downward-facing sensor measures the quadrotor’s height above ground. Our goal is to develop autonomous MAV that can avoid obstacles, ensuring safe flight even in complex urban landscapes. The scenario implemented in the study is by introducing obstacle in any directions. When an obstacle is detected by the ultrasonic sensor, the signal will be sent to microcontroller and the attitude of the MAVs, roll or pitch will be adjusted to avoid the obstacle by moving to the counter direction of the obstacle. We conducted 20 trials of experiments by varying the gain values of Proportional Integral Derivative (PID) values, we fine-tune our obstacle avoidance algorithm. Modifications include optimizing roll and pitch adjustments, refining detection height thresholds, and implementing countermeasures after obstacle clearance. The results show that our proposed method has 10% overshoot when detecting any obstacles in different directions to avoid the obstacles. Our findings contribute to the advancement of safe and efficient urban drone operations, bridging the gap between technology and real-world challenges.

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Adenuga, AH, OA Omotesho, RO Babatunde, DP Popoola et G. Opeyemi. « Effect of Fadama III programme on poverty status of rice farming households in Patigi local government area of Kwara state, Nigeria ». Journal of Agriculture, Forestry and the Social Sciences 11, n^o 2 (17 février 2015) : 80–91. http://dx.doi.org/10.4314/joafss.v11i2.8.

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Concern about the menace posed by poverty has led the Nigerian government over the years to devote considerable attentions to alleviating its scourge through various aids and programmes. However, little is known as to the extent to which the objectives of these programmes have been achieved. This study was therefore carried out to examine the micro level effect of the National Fadama III Programme on poverty status of rice farming households in Patigi Local Government Area of Kwara State, Nigeria. A purposive- two stage random sampling technique was used to select 60 beneficiaries and 60 non-beneficiaries of the programme using a well structured questionnaire. Descriptive statistics, Foster Greer Thorbecke model and the Tobit regression model were the major analytical tools employed. The results obtained from the headcount indices showed that, 33% and 60% of the beneficiaries and non-beneficiaries respectively are poor. The poverty gap indices were 0.36 and 0.45 for Fadama III and non Fadama III farmers respectively while the squared poverty gap was 0.17 and 0.22 respectively. The result of the Paired t-test showed that the National Fadama III programme impacted positively and significantly on the beneficiaries’ welfare. The Tobit regression analysis revealed, that household size, farm income, educational level of the household head, age and beneficiary status were the major determinants of poverty in the study area. Based on findings of the study, it was recommended that farming households especially women should be given increased access to programmes such as the National fadama III programme to improve their welfare and increase agricultural production in the country.Keywords: Fadama III; poverty; Tobit; Beneficiaries; Patigi

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Deng, Jie, Zhu Peng, Zhe Xiao, Shuang Song, Hui Dai et Luming Li. « Porous Doped Carbons from Anthracite for High-Performance Supercapacitors ». Applied Sciences 10, n^o 3 (6 février 2020) : 1081. http://dx.doi.org/10.3390/app10031081.

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Carbon-based materials, as some of the most important electrode materials for supercapacitors (SC), have spurred enormous attentions. Now, it is highly desirable but remains an open challenge to design stable and high-capacity carbons for further enhancing supercapacitive function. Here, a facile chemical activation recipe is introduced to develop biomass-derived functional carbons using cheap and abundant natural resources, anthracite, as the heteroatom-rich carbon sources, and potassium hydroxide (KOH) as activator. These porous carbons have high BET surface areas of roughly 2814 m2 g−1, large pore volumes of up to 1.531 cm3 g−1, and a high porosity that combines micro- and small-sized mesopores. The optimal nanocarbon features two additional outstanding virtues: an appropriate N-doping level (2.77%) and a uniform pore size distribution in the narrow range of 1–4 nm. Synergy of the above unique structural traits and desirable chemical composition endows resultant samples with the much boosted supercapacitive property with remarkable specific capacitance at varied current densities (e.g., 325 F g−1 at 0.5 A/g), impressive energy/power density, and long cycling stability over 5000 cycles at 10 A g−1 (92% capacity retention). When constructing the symmetric supercapacitor utilizing a common neutral Na2SO4 electrolyte that can strongly circumvent the corrosion effect occurring in the strong acid/alkaline solutions, both an elevated operation voltage at 1.8 V and a fascinating energy density of 23.5 Wh kg−1 are attained. The current study paves the way to explore the stable, efficient, and high-voltage SC assembled by the anthracite-derived porous doped nanocarbons for a wide spectrum of applications like automobiles, vehicle devices, and so on.

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Semez, Gianfranco, Carmen Todea, Daliana Mocuta, Ioana Tuta Sas et Ruxandra Luca. « Chemical and Morphologic Analysis of Titanium Dental Implants : X-ray Photoemission Techniques (XPS) and Scanning Electron Microscopy (SEM) with EDX Analysis ». Revista de Chimie 69, n^o 2 (15 mars 2018) : 474–77. http://dx.doi.org/10.37358/rc.18.2.6130.

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Nowadays the implants rehabilitations are used deeply by clinicians. The importance to technological improvement is working to find the best surface of the fixture to obtain a good and stable osteointegration. By the use of the Energy Dispersive X-ray (EDX) analysis and the X-ray Photoemission Spectroscopy (XPS) evaluate the surface quality of commercial implants. The XPS analysis was made to evaluate the chemical elements that compose the material surface of the implant and determine the state of atomical connections. The EDX analysis was performed to evaluate the characteristic qualitative and quantitative of the metallic alloys of the fixtures to determinate the pureness of the metals under the surfaces. The major difference found between the samples is the amount of surface aluminum (in oxidized state, alumina), which in the samples 2 appears to be more than an order of magnitude greater (12 times). In Sample 2 there are traces of P, Na and Cl not present in Sample 1. The presence of C, O, N, Si and Ca are similar on both samples (1 and 2). Now, in the market there are many different dental implants. All the producers are working hard on micro and macro design of the fixtures, but not so many attentions is spent on the type of the alloy composing the implant. From this analysis, it is observed that different Type 4 dental implant are not so similar by composition. Moreover, the pure Titanium is well tolerated by biological tissues, on the other hand is not well known if the presence of other materials can influence the biological reaction. The samples of the fixture analyzed present different composition of the alloy, although both classified as Type 5 Titanium. Further studies on this topic are needed to understand if these differences of alloy composition can influence the clinical outcome.

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Citton, Yves. « Automatic Endo-Attention, Creative ExoAttention : the Egocidal and Ecocidal Logic of Neoliberal Capitalism ». New Formations 98, n^o 98 (1 juillet 2019) : 101–18. http://dx.doi.org/10.3898/newf:98.07.2019.

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The beginning of the twenty-first century could be characterised by the externalisation of attention, following the externalisation of our other faculties: the term 'exo-attention' can be used to refer to the increasing number of electrical devices performing attentional tasks for us outside of our bodies. At the same time, the logic of industrial production continues to demand human beings to develop automated gestures commanded by the planetary assembly line, intellectual gestures being now added to bodily gestures. This automation of our 'endo-attention' cannot be considered as a temporary step in the process leading to full automation. On the one hand, it coexists and goes along with the logic of 'heteromation', whereby supposedly automated procedures are actually performed by micro-taskers, click farms and Mechanical Turks. On the other hand, the precarisation of labour conditions analysed by Franco Berardi tends to segment our activity into pre-formatted time-cells which alienate us from the very tasks we accomplish. While our endo-attention threatens to be automated through and through, progress in deep learning programming allows exo-attention to become creative: what used to be the specificity of human attention (i.e., its capacity to extract a meaningful figure from a given background) can now be obtained by unsupervised machine learning. Does all this mean that the creativity of human attention has been merely displaced, from creatively paying attention to (a limited number of) things, to creatively devising algorithms that pay attention to (a higher number of) things? This perspective could be technologically attractive, if it weren't trapped within the constraints of neoliberal capitalism. Social – not technological – logics should be the main cause of our concern (and anxiety) about automation. Neoliberal capitalism tends to globally align the infinite diversity of our individual attentions under one single hegemonic imperative to maximise financial profit. This is both egocidal, as it automatises our endo-attention subjected to segmented tasks that no longer make sense to us (pre-empting emancipatory forms of subjectification), and eco-cidal, as the race for short-term profit vandalises our social and natural environments. We therefore need to sharpen our analyses (and anxieties), in order to deflect our fear of automation towards a rejection of neoliberal capitalism.

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Li, Bin. « Unlocking Failure Mechanisms and Improvement of Practical Li-S Pouch Cells through in Operando Pressure Study ». ECS Meeting Abstracts MA2022-01, n^o 1 (7 juillet 2022) : 109. http://dx.doi.org/10.1149/ma2022-011109mtgabs.

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Lithium-sulfur (Li-S) batteries have been considered a promising candidate for next-generation high-energy density storage technology due to their low cost and high theoretical capacity. However, since 2017, more and more attentions have been paid to the gap of lab cell characterization (coin cell) and prototype cell (pouch cell) development since misinterpretations and false expectations are frequently reported: material property impacts are often over-interpreted, while parameters with indirect impact (e.g., electrode and separator porosity, tortuosity, and pressure on cell stack) are neglected. In order to accelerate Li-S battery commercialization, the rapid transfer of material-related concept discovered in coin cells to a pouch cell level is essential, as some problems ignored or deemed minimal at the smaller level could have a greater effect on the performance of the larger pouch cell. The issues existing in practical pouch cell should be discovered, which would shed light on further battery materials development, or inspire the novel approaches to identify cell failure and improve cell performances at the pouch cell level. Considering the gap between practical pouch cells and coin cells, in addition to the noticeable difference in electrode size (e.g., the electrode size of practical pouch cell is usually >100 times of that of coin cell), a much higher stack pressure (> 1Mpa) is usually applied inside the coin cell. It was taken for granted that stack pressure was playing a critical role, leading to inconsistent performance between pouch cells and coin cells. Furthermore, with increasing size of the cells (especially for multi-layer pouch cells), the electrolyte wettability needs to be taken seriously. Otherwise, the sulfur utilization would be largely reduced as ionic conduction pathways was significantly affected. Herein, we rationally designed two kinds of cathode: Non-calendared sulfur electrode (NCSE) and Calendared sulfur electrode (CSE). The former’s porosity (ε) and tortuosity (τ) were proven to change with stack pressures while the latter’s do not change by simulations based on micro-XCT results with in-situ pressure applied. These two sulfur cathodes provide preconditions to distinguish the effects of stack pressure and porosity/tortuosity on Li-S pouch cell performances. For the first time, through in-situ monitoring of pressure applied onto Li-S pouch cells, the failure mechanisms of Li-S pouch cells were deeply understood, and the approaches to improve Li-S pouch cell performances were identified. It is found that highly porous structures of cathodes/separators and slow electrolyte diffusion through cathodes/separators can both lead to poor initial wetting. Additionally, Li-metal anode dominates the thickness variation of the whole pouch cell, which is verified by in situ measured pressure variation. Consequently, a real-time approach that combined normalized pressure with dP/dV analysis is proposed and validated to diagnose the morphology evolution of Li-metal anode. Moreover, applied pressure and porosity/tortuosity ratio of the cathode are both identified as independent factors that influence anode performance. In addition to stabilizing anodes, high pressure is proven to improve the cathode connectivity and avoid cathode cracking over cycling, which improves the possibility of developing cathodes with high sulfur mass loading. This work provides insights into Li-S pouch cell design (e.g., cathode and separator) and highlights pathways to improve cell capacity and cycling performance with applied and monitored pressure. Figure 1

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Yang, Bing, Jing Cheng, Yunxiang Yang, Bo Zhang et Jianxin Li. « MERTA : micro-expression recognition with ternary attentions ». Multimedia Tools and Applications, 24 juin 2019. http://dx.doi.org/10.1007/s11042-019-07896-4.

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Jiang, Mingming, Kai Tang, Peng Wan, Tong Xu, Haiying Xu et Caixia Kan. « Single microwire near-infrared exciton-polariton light-emitting diode ». Nanoscale, 2020. http://dx.doi.org/10.1039/d0nr07305a.

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Exciton-polaritons, which inherited from the strong coupling between photon modes of microresonators and excitons in semiconductor micro-/nanostructures, have drawn observably attentions due to their essential significance for fabricating coherent light...

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Xu, Haiying, Juan Xu, Mingming Jiang, Maosheng Liu, Kai Tang, Caixia Kan et Daning Shi. « Exciton-polariton light-emitting diode based on single ZnO super- lattice microwire heterojunction with performance enhanced by Rh nanostructures ». Physical Chemistry Chemical Physics, 2023. http://dx.doi.org/10.1039/d2cp05446a.

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One-dimensional (1D) wirelike superlattice micro/nanostructures have caused considerable attentions for potential applications due to their versatility and capability of modulating optical and electrical characteristics. In this study, 1D superlattice microwires...

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Song, Yuhui, Yifei Cao, Sichen Huang, Kaichao Li, Ruhai Du, Lei Yan et Zhenglong Zhang. « Plasmon-induced nonlinear response on gold nanoclusters ». Chinese Physics B, 4 janvier 2024. http://dx.doi.org/10.1088/1674-1056/ad1a8b.

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Abstract Plasmon-induced nonlinear response has attracted great attentions in micro-nano optics and optoelectronics applications, yet the underlying microscopic mechanism remains elusive. In this study, the nonlinear response of gold nanoclusters when exposed to femtosecond laser pulse was investigated using time-dependent density functional theory (TDDFT). It was observed that the third-order tunneling current was augmented in plasmonic dimers, owing to a greater number of electrons in the dimer being excited from occupied to unoccupied states. These findings provide profound theoretical insights and enable to realize accurate regulation and control of nonlinear effects induced by plasmon at the atomic level.

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Cao, Jinchen, Leilei Li et Cheng Zhang. « The coalescence of Cu nanoparticles with different interfacial lattice structures : A molecular dynamics study ». Modern Physics Letters B, 30 décembre 2020, 2150149. http://dx.doi.org/10.1142/s0217984921501499.

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With the popularization of 3D printing technology, micro/nanoparticles sintering technology has drawn lots of attentions all over the world. Here, molecular dynamic simulation is employed to discuss the effects of different interfacial lattice structures, different diameter of nanoparticles, and different heating rates on the coalescence of metallic Cu nanoparticles. The results showed that the diameter of nanoparticles determine the melting point of the system. Besides, the interfacial lattice structure, diameter of nanoparticles, and heating rate have an influence on the initial sintering temperature. This is because the melting point is the inherent property of material which relies on the mass of substance. However, the initial sintering temperature is sensitive to many factors, including the temperature, interfacial, and intermolecular interactions.

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Feng, Yuming, Junkao Liu, Jie Deng, Zhang Shijing et Yingxiang Liu. « A review on droplet-based 3D printing with piezoelectric micro-jet device ». Smart Materials and Structures, 16 mai 2024. http://dx.doi.org/10.1088/1361-665x/ad4cac.

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Abstract The droplet-based 3D printing with piezoelectric micro-jet device (PMJD), also known as fabrication with droplet ejection, has shown its unique advantages exceeding typical processing in direct rapid manufacturing (DRM) of miniature and complicated metal parts, function components, and other heterogeneous devices. Recently, the droplet-based 3D printing with higher printing velocity, controllable precision and smaller printing volume is need more and more in additive manufacturing (AM) fields, which promotes the development of the droplet-based printing technology to a faster, accurate and flexible direction. In this regard, the droplet-based 3D printing with PMJD has received a lot of attentions from universities, enterprises, and other research institutes. In this review, based on introducing the droplet-based 3D printing technologies, we will clarify the advantages of droplet-based 3D printing, especially the droplet ejection with PMJD. Then, the connections and differences between the ejection of non-metallic droplets and metal droplets based on piezoelectric micro-jet are also clarified, meanwhile, the challenges, such as the consistency, reliability, and stability of piezoelectric actuated droplet ejection, are concluded and analyzed. In general, the future developments of droplet-based 3D printing technology are prospected, and the review can provide some further references for the related works.

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Zhu, Yichen, et Jinjun Wang. « Experimental investigation on flow structures of steadily translating low-aspect-ratio wings in low Reynolds number flow ». 14th International Symposium on Particle Image Velocimetry 1, n^o 1 (1 août 2021). http://dx.doi.org/10.18409/ispiv.v1i1.109.

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In recent decades, Micro Air Vehicles (MAVs) have been a hot topic for their promising future. But the promotions of MAVs are hindered by their short endurances. To solve this problem, inspirations are brought from migratory butterflies who utilize the ‘flapping-gliding’ skill during long-distance migration to improve the flight efficiency. The butterfly’s gliding flights, which can be simplified by considering the steadily translating fixed wings, have drawn high attentions. Previous studies mainly focus on the aerodynamics of the low-aspect-ratio fixed wings at Re ≈ 105 via force measurements. However, few experimental studies have measured the 3D flow fields. Consequently, the underlying high lift-to-drag ratio mechanisms in the steadily translating butterfly-shaped wings are still not clear. To shed new light on this problem, the 3D flow structures around butterfly-shaped wings were captured and investigated in detail.

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Wang, Pengjie, Xiangguang Kong, Fugong Qi, Jiyu Zhou, Haimin Ding et Qing Peng. « Critical pulse in multi-shot femtosecond laser ablation on metallic surfaces ». Nanotechnology, 21 février 2024. http://dx.doi.org/10.1088/1361-6528/ad2bcf.

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Abstract Thermal effect remains a thorny issue for femtosecond-laser surface engineering and nanostructuring on metallic targets with high pulse energies or high repetition rates, which needs to be paid adequate attentions. Herein, we have experimentally investigated the heat diffusion and accumulations during single-shot and multi-shot femtosecond laser ablation on metallic surfaces. We have for the first time observed a novel phenomenon that the thermal effect was intensified abruptly when the laser-pulse number goes over a threshold (approximately between 10 and 20 for aluminum alloy with laser fluence of 6 J cm-2), accompanied with a dramatic reduction of ablated depth and complicated plasma dynamics. Based on both optical and thermodynamic analysis, we introduced a defocusing-dominated plasma-assistant model for this abnormal thermal effect. This work explored the critical experimental parameters for femtosecond-laser surface modification and processing in micro-scale engineering applications.

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Arifin, Agus, FX Sugiyanto et Wahyu Widodo. « Comparing Moral Hazard Behaviour of Micro and Small Enterprises on Productive Business Loan Repayment ». Media Ekonomi dan Manajemen 34, n^o 1 (16 janvier 2019). http://dx.doi.org/10.24856/mem.v34i1.932.

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<p>This research aims to measure and compare the moral hazard behaviour of micro and small enterprises’ debtors within Purwokerto area on Productive Business Loan scheme. This scheme was choosen because of the highest Non Performing Loan (NPL) among others. The data were collected from 127 debitors by using simple random sampling technique. Rating scale method was used to measure the moral hazard behaviours of debtors through questionnaire and later comparing them to study how serious the noncompliance rate in repaying off their credits. This research finds that (1) Generally, the moral hazard behaviour tends to be medium-to-high, (2) The highest moral hazard should be attributed to debitors in Purbalingga followed by those in Banjarnegara, Purwokerto, and Cilacap. Then, it suggests that (1) all bank branches need to pay more attentions to their debitors because their moral hazard behaviours have been medium-to-high. (2) Each branch needs to apply specific treatments to the debitors to improve debitors’ installments, i.e building lending relationship as one way of exploring soft information which emphasizes informal approaches, (3) It should be important to design integrated training and practices for bank officers in order to build up their sense of psychological skills in public relationship in order to handle, in turn, those risky debtors.</p>

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