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1
Yu, Xiang Jun, and Ming Yao Yao. "Buffer-Induced Design and Dynamic Response of Wheel Loader ROPS." Advanced Materials Research 314-316 (August 2011): 1591–96. http://dx.doi.org/10.4028/www.scientific.net/amr.314-316.1591.
Повний текст джерелаАнотація:
A new Rollover Protective Structure (ROPS) of the large-scale wheel loader was designed based on a buffer-induced structure. Dynamic Finite Element analysis model of the entire vehicle was created and boundary conditions of typical rollover cases were given. Optimization design of this new ROPS was obtained through a comprehensive analysis of 16 dynamic simulation samples, which were designed by Orthogonal Experimental Method. Comparison analysis of dynamic response results between original ROPS and optimal new ROPS indicates that this new ROPS effectively prolonged the duration time of the first collision and reduced the acting time of peak force. Deformation extent of main structure of this new ROPS is significantly smaller than that of the original ROPS. Buffer-induced structures can increase the kinetic energy absorption capability of ROPS. Therefore, it can reduce the possibility of brittle fracture of ROPS and improve the probability of operator survival.
2
Li, Yi Ping. "Study on Impact Properties of New Hydro-Pneumatic Buffer for a Metro Vehicle." Advanced Materials Research 978 (June 2014): 94–100. http://dx.doi.org/10.4028/www.scientific.net/amr.978.94.
Повний текст джерелаАнотація:
Analyzed and studied the hydro-pneumatic buffer structure of railway vehicle, designed a new type of hydro-pneumatic buffer and established the detailed dynamics model. Calculated the static characteristic curve of hydro-pneumatic buffer with different compression rate and dynamic characteristic curve with different impact speed through the numerical simulation method. The simulation results shows that the biggest impedance force is 1836.3KN and buffer capacity reach 221.89KJ when impact velocity of the new hydro-pneumatic buffer is 5m/s.New hydro-pneumatic buffer can improve the speed of manipulating vehicle, reduce the longitudinal impact and vibration in the train and adapt to the needs of the trains.
3
Lin, Wei, Maojun Wang, Haozhe Sun, Bing Xie, Cheng P. Wen, Yilong Hao, and Bo Shen. "Suppressing Buffer-Induced Current Collapse in GaN HEMTs with a Source-Connected p-GaN (SCPG): A Simulation Study." Electronics 10, no. 8 (April 15, 2021): 942. http://dx.doi.org/10.3390/electronics10080942.
Повний текст джерелаАнотація:
Carbon doping in the buffer of AlGaN/GaN high-electron-mobility transistors (HEMTs) leads to the notorious current collapse phenomenon. In this paper, an HEMT structure with a source-connected p-GaN (SCPG) embedded in the carbon-doped semi-insulating buffer is proposed to suppress the buffer-induced current collapse effect. Two-dimensional transient simulation was carried out to show the successful suppression of buffer-induced current collapse in the SCPG-HEMTs compared with conventional HEMTs. The mechanism of suppressing dynamic on-resistance degradation by ejecting holes from the SCPG into the high resistive buffer layer after off-state stress is illustrated based on energy band diagrams. This paper contributes an innovative device structure to potentially solve the buffer-induced degradation of the dynamic on-resistance in GaN power devices.
4
Zhang, Jing, Hong Guang Jia, Ling Ding, and Wen Hui Dong. "Buffer and Vibration Optimization of Missile Data Recorder Structure." Advanced Materials Research 328-330 (September 2011): 2304–7. http://dx.doi.org/10.4028/www.scientific.net/amr.328-330.2304.
Повний текст джерелаАнотація:
On the analysis of the original data recorder, made several key problems clear when buffer and damping, distinguished between a cushion theory and application field of stress wave theory, the traditional rigid spring-buffer model whose object is to reduce the impact of acceleration that can not accurately describe the elastic force of the part of the actual situation; the stress wave theory is the elastic theory can explain the filter buffer question from the micro-small space, from this designed a composite structure for vibration reduction, which made the dynamic stress of protected component down about one order of magnitude. Optimization with Isight and Ls-dyna, the protected component's dynamic stress down about 69.3% and the data recorder's quality 300g lower, finally passed the Marshall Hammer test successfully.
5
Peng, Song Jiang, Cheng Zhou, and Cun Gui Yu. "The Numerical Simulation of Three-Dimensional Dynamic-Mesh Flow Field of a Hydraulic Buffer." Advanced Materials Research 588-589 (November 2012): 1264–68. http://dx.doi.org/10.4028/www.scientific.net/amr.588-589.1264.
Повний текст джерелаАнотація:
In order to study the dynamic changes of the internal flow field physical quantities in the hydraulic buffer of a special equipment, based on the Computational Fluid Dynamics (CFD), a three-dimensional incompressible and viscous model under unsteady condition is created. The model keeps the control rod of varying diameter and non-working chamber cover, simulates the turbulent in the flow field of the hydraulic buffer of the special equipment with dynamic meshing technology. From the results, the distributions of velocity in flow field and pressure in chamber are got. It shows that there are negative pressure areas in the non-working chamber and that will lead to cavitation. The results give us a great reference to improve the structure of hydraulic buffer.
6
Zhang, Penghao, Luyu Wang, Kaiyue Zhu, Qiang Wang, Maolin Pan, Ziqiang Huang, Yannan Yang, et al. "Non-Buffer Epi-AlGaN/GaN on SiC for High-Performance Depletion-Mode MIS-HEMTs Fabrication." Micromachines 14, no. 8 (July 29, 2023): 1523. http://dx.doi.org/10.3390/mi14081523.
Повний текст джерелаАнотація:
A systematic study of epi-AlGaN/GaN on a SiC substrate was conducted through a comprehensive analysis of material properties and device performance. In this novel epitaxial design, an AlGaN/GaN channel layer was grown directly on the AlN nucleation layer, without the conventional doped thick buffer layer. Compared to the conventional epi-structures on the SiC and Si substrates, the non-buffer epi-AlGaN/GaN structure had a better crystalline quality and surface morphology, with reliable control of growth stress. Hall measurements showed that the novel structure exhibited comparable transport properties to the conventional epi-structure on the SiC substrate, regardless of the buffer layer. Furthermore, almost unchanged carrier distribution from room temperature to 150 °C indicated excellent two-dimensional electron gas (2DEG) confinement due to the pulling effect of the conduction band from the nucleation layer as a back-barrier. High-performance depletion-mode MIS-HEMTs were demonstrated with on-resistance of 5.84 Ω·mm and an output current of 1002 mA/mm. The dynamic characteristics showed a much smaller decrease in the saturation current (only ~7%), with a quiescent drain bias of 40 V, which was strong evidence of less electron trapping owing to the high-quality non-buffer AlGaN/GaN epitaxial growth.
7
Wan, Lirong, Xuehui Yu, Dejian Ma, Zhaosheng Meng, Qingliang Zeng, and Guoqing Qi. "Dynamic Response Analysis of a Novel Anti-Impact Pressure Balance Jack." Energies 15, no. 14 (July 19, 2022): 5236. http://dx.doi.org/10.3390/en15145236.
Повний текст джерелаАнотація:
Coal resources perform an important role in China’s energy structure. Hydraulic support is the main supporting equipment of fully mechanized mining face in coal mines. Because the hydraulic support frequently bears the impact pressure from the working face, it is very easy to cause failure of the balance jack. In order to solve the problem that the balance jack easily damaged by impact and improve the impact resistance of the hydraulic support, an improved fast response balance jack with multiple adaptive buffers was proposed in this paper. The energy dissipation characteristics of the balance jack were analyzed by establishing the mathematical model of the multiple buffering process of it. Based on ADAMS, the dynamic simulation model of the hydraulic support was constructed, and the mechanical response characteristics of the proposed balance jack and the traditional balance jack under different impact loads were compared and analyzed. By changing the equivalent stiffness of the novel balance jack system, the influence of different initial inflation pressure and length of the buffer cavity on the dynamic performance of the novel balance jack was discussed. The results show that compared with the traditional balance jack, the multi-adaptive response balance jack proposed in this paper can reduce the peak force of the hinge point by about 24.6% and the fluctuation frequency was also significantly reduced under the ultimate load condition at the front end of the top beam, which has better impact resistance. When the initial inflation pressure of the buffer cavity is 40~45 MPa and the initial length is less than 105 mm, a better buffer effect can be achieved. This study provides a new solution to solve the failure problem of the balance jack under the underground impact pressure and improve the safety and reliability of hydraulic support.
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Zhang, Yuan, Li Li Zhou, Jian Wang, and Chang Zhen Fan. "Research on Dynamics Simulation of Buffering Process of Docking Mechanism." Applied Mechanics and Materials 701-702 (December 2014): 748–52. http://dx.doi.org/10.4028/www.scientific.net/amm.701-702.748.
Повний текст джерелаАнотація:
On-orbit service technology can extend the working life of the spacecraft, and improve the ability to perform various tasks. Docking mechanism is the key equipment of the space docking. The cushion performance of the system determines the dynamic characteristics in the docking process, and it is one of the important factors influencing the docking success or not. It is established that mathematical modeling of the new grasping mechanism in the buffering process, due to lack of the experiment equipments, the dynamic simulation on computer is an effective method to test and verify the parameters or evaluate the performance of the buffer system designed. Simulation analysis is conducted to get the corresponding buffer force for four different sets of buffer parameter, and it provides important basis for docking cushioning structure optimization.
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Yu, Z. X., L. Zhao, L. P. Guo, Y. P. Liu, C. Yang, and S. C. Zhao. "Full-Scale Impact Test and Numerical Simulation of a New-Type Resilient Rock-Shed Flexible Buffer Structure." Shock and Vibration 2019 (May 2, 2019): 1–16. http://dx.doi.org/10.1155/2019/7934696.
Повний текст джерелаАнотація:
Rock sheds have been widely used to protect against rockfall. Traditionally, a cushion layer is placed on the top of a rock shed to reduce the impact force and dissipate energy. However, heavy cushion layers lead to high dead loads and increased construction costs. This paper discusses the concept of an impact-resilient flexible buffer structure. On the basis of that concept, it also proposes a buffer structure mainly composed of springs, ring nets, spring rods, and support ropes, which can be used to replace the traditional cushion layer on a shed for rockfall protection. Full-scale impact tests were conducted to study the impact-resilient characteristic of the structure combined with numerical simulation. The dynamic responses of the buffer structure, including force, deformation, and energy dissipation, were analysed in depth. Finally, parametric numerical simulations of 33 models were conducted; the spring stiffness of these models ranged from 300 kN/m to 1500 kN/m; the impact energy ranged from 100 kJ to 2000 kJ. Moreover, simple approaches for estimating the impact force and braking distance of the buffer structure were proposed and verified using measured data obtained from the impact test.
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Li, Liang, Xing Fa Huang, Ming Yuan Xu, Xiao Feng Shen, and Xi Chen. "A Novel Input Buffer Used for SHA-Less Pipeline ADC." Applied Mechanics and Materials 678 (October 2014): 501–4. http://dx.doi.org/10.4028/www.scientific.net/amm.678.501.
Повний текст джерелаАнотація:
This paper discussed a input buffer structure with replica load, analysed its theory of improving input signal linearity and decreasing distortion, gived some circuit embodiments, one of which was used for a 12-bit 500MSPS SHA-less ADC based on BiCMOS technolgy, Spurious Free Dynamic Range (SFDR) reached above 90dB with a 250MHz input signal.
11
Fan, Chang Ge, Fa Lin Zeng, De Hua Li, and Lei Liu. "Simulation Study of the Hydraulic System of Concrete Pumping Truck Based on AMESim." Applied Mechanics and Materials 170-173 (May 2012): 1920–25. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.1920.
Повний текст джерелаАнотація:
The working principle of concrete pumping hydraulic system was analyzed. And base on the AMESim software, the complete simulation model of concrete pumping hydraulic system was built. A simulation was made to get the dynamic characteristics curve of hydraulic cylinder velocity and displacement at some specific conditions. The simulation results indicate that the model is reasonable. Comparative simulations of the pumping hydraulic system with different positions of buffer structure were carried out to study the relationship between buffer effect and the buffer position which can be used to provide theory basis for deeper study of the hydraulic shock.
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Iyobhebhe, Matthew, Agburu Adikpe, James Gaina Bashayi, Amlabu Caleb Akezi, Ishaya Chollom Botson, Ezugwu Chukwudi, and Omojola Bankole Akinyele. "A Review on Dynamic Buffer Traffic Condition Protocol in Telemedicine." Indonesian Journal of Computing, Engineering and Design (IJoCED) 4, no. 2 (October 3, 2022): 15. http://dx.doi.org/10.35806/ijoced.v4i2.247.
Повний текст джерелаАнотація:
Various MAC-protocol has been adopted over the years in Telemedicine, also known as Wireless Body Area Network system (WBANs), to enhance the proper transmission of the busy congestion of data message. However, these techniques could not coordinate traffic congestion in the receiver node, which could make the receiver nodes experience an "active mode" most of the time compared to the transmit node. This is dangerous to the network system because of uncontrollable energy usage. In this protocol, the intelligent sensor is strategically located around or implanted in the human body for the collection of human body physiological parameters. WBANs experienced some limitations such as latency and excessive consumption of energy which may hinder the lifetime maximization of the system if not taken care of properly. In this work, four elements are responsible for carrying-out only traffic data, and they are implemented by using the highest priority sensor nodes within a short period used for communicating to the Buffer Traffic Condition (BTC) discussed and the traffic measurement to mitigate active-mode interval in the receiving phase of the improved superframe structure of IEEE 802.15.6. Furthermore, meaningful information about the superframe to mitigate the busy traffic and enhance this protocol was also discussed as its possible functions with the help of an adaptive system. No article depicts the analysis of the work on the dynamic buffer traffic condition scheme, and this proposed scheme can improve on the existing one.
13
Lu, Shan, Bao Hua Wang, and Ya Ping Qi. "Dynamics Simulation of Automatic Rifle." Advanced Materials Research 482-484 (February 2012): 1547–50. http://dx.doi.org/10.4028/www.scientific.net/amr.482-484.1547.
Повний текст джерелаАнотація:
By using dynamic simulation method, the launching technique of high firing rate for automatic rifle was studied. The influence of structure parameters of airway device, the stiffness of buffer spring and return spring on firing rate was studied. The simulation results provide the reference for the designing of high firing rate automatic rifle.
14
Wang, Chien-Chih, Chin-Hua Chen, and Bernard C. Jiang. "Shock Absorption Characteristics and Optimal Design of Corrugated Fiberboard Using Drop Testing." Applied Sciences 11, no. 13 (June 23, 2021): 5815. http://dx.doi.org/10.3390/app11135815.
Повний текст джерелаАнотація:
The application of corrugated paper to buffer packaging has increased with the rise of the circular economy. The dynamic buffer curve is the key to designing the buffer packaging structure but requires multiple testing by small- and medium-sized enterprises (SMEs) without resources. In this study, we propose drop testing to perform a fractional factorial experiment and establish a regression model of impact strength through experimental data. The analysis results show that static stress, falling height, and buffer material thickness are the key variables of impact strength, and an impact strength prediction model (R2 = 94.1%) was obtained. Model verification using the buffer package design of a personal computer showed that the measured values of impact strength fell within the estimated 95% confidence interval. These results indicate that SMEs can use the proposed analysis procedure to improve the design of corrugated paper using minimal resources.
15
Sergienko, Anatolij M., Vitalij O. Romankevich, and Pavlo A. Serhiienko. "Image buffering in application specific processors." Applied Aspects of Information Technology 5, no. 3 (October 25, 2022): 228–39. http://dx.doi.org/10.15276/aait.05.2022.16.
Повний текст джерелаАнотація:
In many digital image-processingapplications, which are implementedin field programmable gate arrays,the currently processed image's frames are stored in external dynamic memory.The performance of such an application dependson the dynamic memoryspeed and the necessaryrequests quantity during algorithm’sruntime. This performance is being optimized through field programmable gate arrays -implemented buffer memory usage.But there is no common method for the formal buffer memory synthesis with preset throughput, input and output data sequenceorderand minimizedhardwarecosts.In this article,the featuresof image input and processing based on Field Programmable Gate Arrayareconsidered.The methods of building buffer circuits in field programmable gate arrays, due to which the intensity of data exchanges with external memory is reduced, are analyzed. Themethod of synthesizing pipeline circuits with specified performance characteristics and the data sequence order is given, which is based on the mapping of the spatial synchronous data flows into the structure implemented in the field programmable gate arrays.A method of designing buffer schemes is proposed, which is based on the mapping of spatial synchronous data flows into local memory in the form of chains of pipeline registers.The method helpsto organize the data flow of at the input of built-in pipeline units of image processing, in which the data follow in a given order, andto minimize the amount of buffer memory.The method ensures the use of dynamically adjustable register delays built into the field programmable gate arrays, which increases the efficiency of buffering.Thismethod was tested during the development of an intelligent video camera. The embedded hardware implements a video image compression algorithm with a wide dynamic range according to the Retinexalgorithm. The same time it selects characteristic points in the image for the further pattern recognition.At the same time, multiple decimation of the frame is performed. Due to themultirate buffering of the image in the field programmable gate arrays,it was possible to avoid using of external dynamic memory
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Farrell, Brian F., Petros J. Ioannou, Javier Jiménez, Navid C. Constantinou, Adrián Lozano-Durán, and Marios-Andreas Nikolaidis. "A statistical state dynamics-based study of the structure and mechanism of large-scale motions in plane Poiseuille flow." Journal of Fluid Mechanics 809 (November 9, 2016): 290–315. http://dx.doi.org/10.1017/jfm.2016.661.
Повний текст джерелаАнотація:
The perspective of statistical state dynamics (SSD) has recently been applied to the study of mechanisms underlying turbulence in a variety of physical systems. An SSD is a dynamical system that evolves a representation of the statistical state of the system. An example of an SSD is the second-order cumulant closure referred to as stochastic structural stability theory (S3T), which has provided insight into the dynamics of wall turbulence, and specifically the emergence and maintenance of the roll/streak structure. S3T comprises a coupled set of equations for the streamwise mean and perturbation covariance, in which nonlinear interactions among the perturbations has been removed, restricting nonlinearity in the dynamics to that of the mean equation and the interaction between the mean and perturbation covariance. In this work, this quasi-linear restriction of the dynamics is used to study the structure and dynamics of turbulence in plane Poiseuille flow at moderately high Reynolds numbers in a closely related dynamical system, referred to as the restricted nonlinear (RNL) system. Simulations using this RNL system reveal that the essential features of wall-turbulence dynamics are retained. Consistent with previous analyses based on the S3T version of SSD, the RNL system spontaneously limits the support of its turbulence to a small set of streamwise Fourier components, giving rise to a naturally minimal representation of its turbulence dynamics. Although greatly simplified, this RNL turbulence exhibits natural-looking structures and statistics, albeit with quantitative differences from those in direct numerical simulations (DNS) of the full equations. Surprisingly, even when further truncation of the perturbation support to a single streamwise component is imposed, the RNL system continues to self-sustain turbulence with qualitatively realistic structure and dynamic properties. RNL turbulence at the Reynolds numbers studied is dominated by the roll/streak structure in the buffer layer and similar very large-scale structure (VLSM) in the outer layer. In this work, diagnostics of the structure, spectrum and energetics of RNL and DNS turbulence are used to demonstrate that the roll/streak dynamics supporting the turbulence in the buffer and logarithmic layer is essentially similar in RNL and DNS.
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Sun, Wen Jing, Dao Gong, and Jin Song Zhou. "Study on Wheel-Rail Coupled Vibration of Metro with Co-Simulation of Finite Element Analysis and Multi-Body Dynamics Simulation." Applied Mechanics and Materials 752-753 (April 2015): 636–41. http://dx.doi.org/10.4028/www.scientific.net/amm.752-753.636.
Повний текст джерелаАнотація:
Based on the multi-body dynamics theory and modal-reduction analysis, finite element method and multi-body dynamics were combined to establish the flexible track model. The rigid-flexible coupled dynamics model can reflect the features of coupled vibration accurately. When the flexibility of the rail, damping and stiffness of support layers under the rail are taken into consideration, the whole track structure acted as a buffer while wheel and rail is interacting with each other. Compared with rigid track model, the wheel-rail vibration is less in the flexible track model. The proposed method in this paper is simple and effective, which makes the calculation of vehicle-track dynamic response more convenient and quick.
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Souilem, Malek, Jai Narayan Tripathi, Rui Melicio, Wael Dghais, Hamdi Belgacem, and Eduardo M. G. Rodrigues. "Neural-Network Based Modeling of I/O Buffer Predriver under Power/Ground Supply Voltage Variations." Sensors 21, no. 18 (September 10, 2021): 6074. http://dx.doi.org/10.3390/s21186074.
Повний текст джерелаАнотація:
This paper presents a neural-network based nonlinear behavioral modelling of I/O buffer that accounts for timing distortion introduced by nonlinear switching behavior of the predriver electrical circuit under power and ground supply voltage (PGSV) variations. Model structure and I/O device characterization along with extraction procedure were described. The last stage of the I/O buffer is modelled as nonlinear current-voltage (I-V) and capacitance voltage (C-V) functions capturing the nonlinear dynamic impedances of the pull-up and pull-down transistors. The mathematical model structure of the predriver was derived from the analysis of the large-signal electrical circuit switching behavior. Accordingly, a generic and surrogate multilayer neural network (NN) structure was considered in this work. Timing series data which reflects the nonlinear switching behavior of the multistage predriver’s circuit PGSV variations, were used to train the NN model. The proposed model was implemented in the time-domain solver and validated against the reference transistor level (TL) model and the state-of-the-art input-output buffer information specification (IBIS) behavioral model under different scenarios. The analysis of jitter was performed using the eye diagrams plotted at different metrics values.
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Xu, Zhuofan, Biao Hu, Tianxiang Wu, Yuting Yao, Yong Chen, Junyan Ren, and Shunli Ma. "A 12-Bit 50 MS/s Split-CDAC-Based SAR ADC Integrating Input Programmable Gain Amplifier and Reference Voltage Buffer." Electronics 11, no. 12 (June 9, 2022): 1841. http://dx.doi.org/10.3390/electronics11121841.
Повний текст джерелаАнотація:
This article describes an asynchronous split-CDAC-based SAR ADC with integrated input PGA and an RV-Buffer. The split CDAC structure not only reduces the area of the ADC, but also relieves the driving pressure of the input PGA and RV-Buffer. Using the input PGA instead of the traditional input buffer as the driving circuit of the ADC increases the dynamic input range of the ADC. The proposed on-chip RV-Buffer can provide 1.1 V positive and 0.1 V negative voltage, avoiding the disturbance caused by off-chip reference. This prototype is implemented in a 65 nm CMOS process and occupies an active area of 0.088 mm2. The input PGA can provide 0–18 dB programmable gain with a step of 3 dB. Measurement results show that as the provided gain changes, the ADC’s SNR is best, reaching 50.9 dB, and the SFDR is beat, reaching 62.35 dB at 50 MS/s.
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Nahar, K., I. Alam, and M. M. Morshed. "Influence of Bypass Road on Land Use and Land Cover Change Of Khulna City, Bangladesh." Journal of Engineering Science 14, no. 1 (July 18, 2023): 11–27. http://dx.doi.org/10.3329/jes.v14i1.67632.
Повний текст джерелаАнотація:
Transportation has a significant impact on the spatial structure of a place and its accessibility. It can shape urban spatial growth, reorganize the country's land use patterns, and stimulate the advancement of specific patterns. In this study, satellite images of Khulna city and its 5 km buffer area centering the bypass road for the years 1990, 2000, 2010, and 2020 were classified to determine the land use changes as the land cover was categorized in water bodies, agriculture, vegetation, and built-up. Using a single dynamic degree, comprehensive dynamic degree, and expansion or reduction intensity index, the change rate and expansion rate of land use were determined within a 1-5 km buffer. It was found that most changes occurred within the 1-2 km buffer zone of the bypass road. As the distance from the road increases, the influence on land use decreases. To determine the land use transition due to the bypass road, a corridor assessment was done for a 2 km and 4 km buffer area, assuming the changes were uniform. The Difference-in-Difference (DID) estimation determined that the bypass has a significantly positive impact on land use changes. A placebo test was conducted to determine whether the changes were due to the bypass road or some other unobservable factor. Journal of Engineering Science 14(1), 2023, 11-27
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Hou, Weijie, Yongbo Hao, Chang Wang, Lei Chen, Guangping Li, Baoshan Zhao, Hao Wang, et al. "Theoretical and Experimental Investigations on High-Precision Micro-Low-Gravity Simulation Technology for Lunar Mobile Vehicle." Sensors 23, no. 7 (March 25, 2023): 3458. http://dx.doi.org/10.3390/s23073458.
Повний текст джерелаАнотація:
With the development of space technology, the functions of lunar vehicles are constantly enriched, and the structure is constantly complicated, which puts forward more stringent requirements for its ground micro-low-gravity simulation test technology. This paper puts forward a high-precision and high-dynamic landing buffer test method based on the principle of magnetic quasi-zero stiffness. Firstly, the micro-low-gravity simulation system for the lunar vehicle was designed. The dynamic model of the system and a position control method based on fuzzy PID parameter tuning were established. Then, the dynamic characteristics of the system were analyzed through joint simulation. At last, a prototype of the lunar vehicle’s vertical constant force support system was built, and a micro-low-gravity landing buffer test was carried out. The results show that the simulation results were in good agreement with the test results. The sensitivity of the system was better than 0.1%, and the constant force deviation was 0.1% under landing impact conditions. The new method and idea are put forward to improve the micro-low-gravity simulation technology of lunar vehicles.
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Chen, Yu-Chih, Indraneel Sanyal, Ting-Yu Hu, Ying-Hao Ju, and Jen-Inn Chyi. "The Influence of Superlattice Structure on the Dynamic Buffer Response of AlInN/GaN-on-Si HEMTs." IEEE Transactions on Nanotechnology 19 (2020): 415–20. http://dx.doi.org/10.1109/tnano.2020.2992312.
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Mao, Xiao Hui. "Structure Transient Response Analysis of Coal Mine Life-Saving Capsule under Blast Shock Condition." Advanced Materials Research 694-697 (May 2013): 120–27. http://dx.doi.org/10.4028/www.scientific.net/amr.694-697.120.
Повний текст джерелаАнотація:
Targeting at insufficient data for simulated blast shock of life saving capsule in coal mine which affects its development and design so that structural transient response analysis optimization was performed to analyze strain-stress, shock-produced deformation and spring-back of the new protective crust with compound structure under shock wave. ADINA, a general-purpose FEA program, is chosen to emulate the dynamic response of the protective structure under blasting stress. The analysis results were compared with the dynamic response results of the single-layer protective crust. The result shows that steel defensive structure with aluminum foam buffer behind general steel has a good attenuation characteristic for peak pressure of blast wave. The composite structure with flexible material layer can protect the core of the lifesaving system better from the blast. The simulation experimental environment can be established and reference data can be provided for the design of a life-saving ball system by using numerical analysis methods.
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Vornicescu, Doru, Katerina Solanska, Ioana Demetrescu, Matthias Frentzen, and Michael Keusgen. "Dynamics of Dental Pellicle Formation - In Vitro Analysis of Time Dependant Binding Behavior by Surface Plasmon Resonance and the Influence of Oral Therapeutics." Key Engineering Materials 415 (September 2009): 77–80. http://dx.doi.org/10.4028/www.scientific.net/kem.415.77.
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: The pellicle on oral surfaces represents a central interface for the formation of biofilms. Among other things it causes the first adsorption of bacteria. The dynamics of pellicle formation, on tooth surfaces and the influence of oral therapeutics on the pellicle structure are fairly unknown. With the method of surface plasmon resonance (SPR), the formation of salivary pellicle structures on hydroxylapatite (HAP) surfaces covering a very thin (~50nm) layer gold on a glass prism was recorded in real time without labeling or destruction. As pellicle forming substrates natural pooled human saliva (NS) and artificial saliva (AS) were used. To simulate the influence of therapeutic additives on the dynamic of the pellicle forming process, a chlorhexidine preparate (Chlorhexamed Fluid® CHX) on two different concentrations was selected. The binding behavior of a NS and a preparation in terms of an AS were compared. The layer was largely stable against rinsing with buffer. The application of CHX preparations in two different concentrations as an example of an oral therapeutic additive revealed a complex dynamic of adsorption. CHX did not lead to any visible destruction of the pellicle. The introduced method is an excellent tool to illustrate the dynamic effects of pellicle formation or pellicle reorganization by measuring the increase or decrease of the SPR signal in real time.
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Bumanis, G., and D. Bajare. "Porous alkali activated materials with slow alkali release dynamic. Role of composition." Materiales de Construcción 68, no. 329 (February 7, 2018): 145. http://dx.doi.org/10.3989/mc.2018.14016.
Повний текст джерелаАнотація:
Alkali activated materials (AAM) based on calcined metakaolin or illite clay together with waste by-products, such as waste glass or aluminium scrap recycling waste, were tested as value-added materials for pH stabilization in biogas technology where decrease of pH should be avoided. Porous materials with ability to slowly leach alkalis in the water media thus providing continuous control of the pH level were obtained. XRD, FTIR, SEM and titration methods were used to characterize AAM and their leaching properties. It is clear that composition of the material has an important effect on the diffusion of alkali from structure. Namely, higher Si/Al and Na/Al molar ratios may increase pore solution transfer to the leachate. The leaching rate of alkalis from the structure of AAM is high for the first few days, decreasing over time. It was possible to calculate the buffer capacity from the mixture design of AAM.
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ABDEL-HAFEEZ, SALEH M., and ANAS S. MATALKAH. "CMOS EIGHT-TRANSISTOR MEMORY CELL FOR LOW-DYNAMIC-POWER HIGH-SPEED EMBEDDED SRAM." Journal of Circuits, Systems and Computers 17, no. 05 (October 2008): 845–63. http://dx.doi.org/10.1142/s0218126608004599.
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Embedded SRAM design with high noise margin between read and write, low power, low supply voltages, and high speed become essential features in VLSI embedded applications. The complete embedded SRAM design of self-timing synchronization is proposed based on the CMOS eight-transistor (8T-Cell) memory cell circuit. The cell is based on the traditional six-transistor (6T-Cell) cross-coupled invertors with the addition of two NMOS transistors for separate read buffer circuit. The read buffer structure is based on pre-charging the read bit-line during the low value of read clock and evaluating the read bit-line during the high value of read clock, thereby maintaining one active line per column and eliminating the use of traditional sense amplifier with all its synchronization schemes. The simulation results show that the embedded SRAM of size 128-bit × 128-bit is operating at a maximum frequency of 200 MHz for Write and Read clock cycles with 1.62 V power supply, and measures a total average power consumption of 22.60 mW. All simulation results were conducted on 0.18 μm TSMC single poly and three layers of metals measuring a cell area of 2.2 × 3.0 μ m 2. The circuit is not meant to replace the SRAM with 6T-Cell transistor structure; however, it is attractive for applications related to high density with automation road-map design, such as graphic and network processor chips. In these applications, memory sizes are introduced in many different irregular geometries and uses all over the chip with storage sizes less than 20 k-bit, in addition, it is susceptible to large substrate noise as well as large coupling wire routing.
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Jendernalik, Waldemar, Jacek Jakusz, and Grzegorz Blakiewicz. "Ladder-Based Synthesis and Design of Low-Frequency Buffer-Based CMOS Filters." Electronics 10, no. 23 (November 26, 2021): 2931. http://dx.doi.org/10.3390/electronics10232931.
Повний текст джерелаАнотація:
Buffer-based CMOS filters are maximally simplified circuits containing as few transistors as possible. Their applications, among others, include nano to micro watt biomedical sensors that process physiological signals of frequencies from 0.01 Hz to about 3 kHz. The order of a buffer-based filter is not greater than two. Hence, to obtain higher-order filters, a cascade of second-order filters is constructed. In this paper, a more general method for buffer-based filter synthesis is developed and presented. The method uses RLC ladder prototypes to obtain filters of arbitrary orders. In addition, a set of novel circuit solutions with ultra-low voltage and power are proposed. The introduced circuits were synthesized and simulated using 180-nm CMOS technology of X-FAB. One of the designed circuits is a fourth-order, low-pass filter that features: 100-Hz passband, 0.4-V supply voltage, power consumption of less than 5 nW, and dynamic range above 60 dB. Moreover, the total capacitance of the proposed filter (31 pF) is 25% lower compared to the structure synthesized using a conventional cascade method (40 pF).
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Li, Mei, Peng Gong, Yifei Wu, and Yi Wu. "Analysis of structure strength for direct current high-speed switch based on flexible body theory." Advances in Mechanical Engineering 12, no. 3 (March 2020): 168781402091298. http://dx.doi.org/10.1177/1687814020912984.
Повний текст джерелаАнотація:
The Thomson coil actuator has an important application prospect in direct current high-speed switch due to its short respond time and fast operation speed. However, the large electromagnetic impact force during the opening process may bring the stress deformation of movable components and thus cause damage to the mechanism. Therefore, the dynamic stress and strain evaluation of the moving parts is very important for the design and optimization of direct current high-speed switch. In this article, a novel method of structure strength analysis based on the flexible body theory is established for direct current high-speed switch. The electromagnetic and buffer forces in the rapid opening process are calculated, and then the stress and strain distribution of the key components are obtained. Finally, the strain test circuit of the key components is built. By comparing the simulation and experimental results of dynamic strain, the validity of the established simulation model is verified.
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Sun, Ye Zun, Jun Qi Qin, Chang Chun Di, Kai Bo Cui, and Yan Wang. "Simulation Analysis on Interior Flow Field of Recoil Brake Based on Dynamic Mesh." Advanced Materials Research 765-767 (September 2013): 427–30. http://dx.doi.org/10.4028/www.scientific.net/amr.765-767.427.
Повний текст джерелаАнотація:
Recoil brake is one of the core components of the artillery. It plays a main buffer role in artillery firing. Its internal flow is very complex, so the traditional one-dimensional computational model can not reflect the characteristics of internal flow field fully and accurately. Two-dimensional computational model of the recoil brake with actual structure was proposed based on dynamic mesh technology. Using dynamic layering method, the movement of dynamic grid was driven by Profile file. The data of Profile file was obtained from experiment measured of artillery recoil. Simulation of the flow field of recoil brake accurately was achieved. Pressure, speed and other data were got by simulation. It also reveals the laws of liquid flow and can provide theoretical support for fault analysis and optimization design.
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Deng, Yaoji, Youqun Zhao, Han Xu, Fen Lin, and Qiuwei Wang. "Rigid-flexible coupling modelling and dynamic performance analysis of novel flexible road wheel." Proceedings of the Institution of Mechanical Engineers, Part K: Journal of Multi-body Dynamics 234, no. 1 (September 11, 2019): 67–81. http://dx.doi.org/10.1177/1464419319874198.
Повний текст джерелаАнотація:
A novel flexible road wheel with hub-hinge-ring combined structure is introduced to improve the buffer damping performance and lightweight level of tracked vehicles. To balance computational efficiency and precision, an advanced rigid-flexible coupled model of the flexible road wheel is established using a hybrid modelling method combining finite element method and multi-body dynamics. The reliability and accuracy of the established rigid-flexible coupled model are verified by wheel static loading experiment. The modal flexible body of the elastic outer ring is developed by modified Craig-Bampton method and the simulated results are in good agreement with the experimental data. Based on the verified rigid-flexible coupled model, the dynamic characteristics of the flexible road wheel under typical operation conditions were investigated. The simulation results show that when the motion state changes, the elastic outer ring will produce a hysteretic angle with respect to the hub, delaying the transmission of torque. The system parameters have a greater effect on the vertical vibration of the flexible road wheel. The higher the vehicle speed, the more vibration will be caused, and the increase in the load and number of hinge groups will reduce the vibration. The research results provide reference for structure optimization of flexible road wheel and lay a foundation for flexible multi-body dynamic simulation of tracked vehicles with flexible road wheels.
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WANG, CHING-JONG. "SIMULATION OF COLLISION CONTACTS AMONG DISJOINED SOIL-STRUCTURE BODIES UNDER SEISMIC MOTIONS." International Journal of Modern Physics B 22, no. 09n11 (April 30, 2008): 1544–51. http://dx.doi.org/10.1142/s0217979208047055.
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Structure bodies and surrounding soils in certain types of bridges and tunnels may be prone to collisions during earthquake. A dynamic system composed of discrete and finite elements is developed using explicit formulation for equations of motion, and nonlinearities in soils and at interfaces of disjoined regions are implemented. Time history solutions are carried out to examine the plastic deformation in soils as well as the integrity of structures. Two case studies are presented in which collisions among disjoined regions are anticipated in the event of extremely large earthquakes. Case one is based on a replica from a quake-stricken bridge, to illustrate that a backfill with moderate soil strength may be used as an energy-dissipating buffer to contain the shaken loose decks. The other case involves an underground subway station box with slurry walls alongside, to exemplify the seismic resistance of the dual-wall system.
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Kienberger, Ferry, Rong Zhu, Rosita Moser, Dieter Blaas, and Peter Hinterdorfer. "Monitoring RNA Release from Human Rhinovirus by Dynamic Force Microscopy." Journal of Virology 78, no. 7 (April 1, 2004): 3203–9. http://dx.doi.org/10.1128/jvi.78.7.3203-3209.2004.
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ABSTRACT Human rhinoviruses were imaged under physiological conditions by dynamic force microscopy. Topographical images revealed various polygonal areas on the surfaces of the 30-nm viral particles. RNA release was initiated by exposure to a low-pH buffer. The lengths of the RNAs that were released but still connected to the virus capsid varied between 40 and 330 nm, whereas RNA molecules that were completely released from the virus were observed with lengths up to 1 μm. Fork-like structure elements with 30-nm extensions were sometimes resolved at one end of the RNA molecules. They possibly correspond to the characteristic multi-stem-loop conformation, the internal ribosomal entry site, located at the 5′ region of the genome. This study demonstrates that dynamic force microscopy can be used to study viral RNA release in situ under physiological conditions.
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Chen, Zhaoyue, Li Liu, and Shulin Chen. "Multi-Domain Substructure Synthesis with Normalized Interpolation Technique for Non-Matching Interfaces." Applied Sciences 13, no. 11 (May 26, 2023): 6525. http://dx.doi.org/10.3390/app13116525.
Повний текст джерелаАнотація:
The dynamic prediction of large spacecraft is a time-consuming process. The impulse-based substructuring (IBS) method is an efficient and accurate method for the dynamic analysis of large-scale structures. The ordinary IBS method couples the substructure impulse response functions (IRFs) with coincident interface nodes. However, the interface nodes in a practical structure are usually mismatched. This paper extends the ordinary IBS method and presents a method for coupling multi-domain substructures, including IBS, FEM and modal substructures, with non-matching interfaces. Both displacement compatibility and force equilibrium are satisfied on the non-matching interfaces of substructures by introducing the normalized interpolation technique into the framework of IBS. To evaluate the performance of the proposed method, numerical models and a practical application with a lunar lander and a rover are presented. The main bodies of the lander and the rover are coupled by non-matching interfaces, and the coupled system is excited by a buffer load. With the employment of this proposed method, the computing time of the landing simulation of the lunar lander is dramatically reduced, and the results show strong agreement with references. It is demonstrated that the proposed method is accurate and efficient in the transient dynamic analysis of engineering structures.
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Mukhopadhyay, Soumen, Nilendra Chatterjee, and Tapan K. Chatterjee. "EVALUATION OF DIACEREIN MICROSPHERE MANUFACTURED BY FLUID BED BOTTOM SPRAY COATING TECHNIQUE AS SUSTAINED RELEASE DRUG DELIVERY FORM." Indian Drugs 59, no. 07 (September 16, 2022): 28–36. http://dx.doi.org/10.53879/id.59.07.13270.
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Diacerein (DCN), an anti- inflammatory, anti-osteoarthritic drug having short-acting properties was formulated as microsphere following fluid bed bottom spray coating technique for sustained release drug delivery, where HPMC (6cps) and ethyl cellulose (N7) were used as coating polymers. Assay of DCN microsphere was done following HPLC method. Drug content in microsphere was found to be 147 mg g-1. Drug entrapment efficiency was calculated as 61%. SEM study of microsphere showed that microsphere was spherical in shape and porous in structure. Particle size, size distribution, zeta potential and poly disparity index were studied by dynamic light scattering method. particle size range was found between 396-615nm, zeta potential 10.8-19.6mv and PDI 0.65. In vitro drug release rate from microsphere was studied in different buffers like phosphate (pH 6.8), citrate (pH 6.0) and acidic medium (0.1N HCL). DCN microsphere released about 97% of its drug content in 20 h in phosphate buffer, 57.8% of its drug content in citrate buffer in 20 h and negligible drug release was found in acidic medium. On the contrary, market preparation of diacerein 50 mg capsule (Orcerin, Macleod’s) released 80% of its drug content in 1 h in phosphate and citrate buffer. Pharmacokinetic study of DCN microsphere vis a vis DCN capsule market preparation in plasma level of rabbit showed as Cmax4.02/3.97 mcg ,Tmax4h/ 2.67h, AUC0-t 21.26/17.80 mcg h mL-1, AUC 0-∞ 21.35/19.38 mcg h mL-1, T1/2 1.98/ 2.30 h and Kel 0.35/0.31. Study as mentioned above showed that DCN microsphere manufactured by fluid bed bottom spray coating technique using HPMC (6cps) and ethyl cellulose (N7) as coating polymers exhibited sustained release drug delivery. So it is a useful method for manufacture of sustained release dosage form.
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Lin, Yuan, Min-Lu Kao, You-Chen Weng, Chang-Fu Dee, Shih-Chen Chen, Hao-Chung Kuo, Chun-Hsiung Lin, and Edward-Yi Chang. "Buffer Traps Effect on GaN-on-Si High-Electron-Mobility Transistor at Different Substrate Voltages." Micromachines 13, no. 12 (December 3, 2022): 2140. http://dx.doi.org/10.3390/mi13122140.
Повний текст джерелаАнотація:
Substrate voltage (VSUB) effects on GaN-on-Si high electron mobility transistors (HEMTs) power application performance with superlattice transition layer structure was investigated. The 2DEG conductivity and buffer stack charge redistribution can be affected by neutral/ionized donor and acceptor traps. As the donor/acceptor traps are excessively ionized or de-ionized by applying VSUB, the depletion region between the unintentionally doped (UID)/Carbon-doped (C-doped) GaN layer may exhibit a behavior similar to the p–n junction. An applied negative VSUB increases the concentration of both the ionized donor and acceptor traps, which increases the breakdown voltage (BV) by alleviating the non-uniform distribution of the vertical electric field. On the other hand, an applied positive VSUB causes the energy band bending flattener to refill the ionized traps and slightly improves the dynamic Ron degradation. Moreover, the amount of electrons injected into the buffer stack layer from the front side (2DEG channel/Ohmic contact) and the back side (AlN nucleation layer/superlattice transition layer) are asymmetric. Therefore, different VSUB can affect the conductivity of 2DEG through the field effect, buffer trapping effect, and charge redistribution, which can change the electrical performance of the device.
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Chen, Fei, Yong Lv, and Zhi Wei Xing. "The Strength Analysis of Aircraft Landing Gear Strut Based on ANSYS." Advanced Materials Research 490-495 (March 2012): 2686–90. http://dx.doi.org/10.4028/www.scientific.net/amr.490-495.2686.
Повний текст джерелаАнотація:
Because the landing gear structure is complicated, it is difficult to draw accurate stress and strain distribution through the theoretical calculation. In this paper, based on the modeling and stress analysis of the buffer mechanism of aircraft landing gear, by converting the stress of a dynamic system into a static stress, the force of the landing gear struts are calculated. This paper analyzes the strength of the aircraft main landing gear by using computer simulation technology and finite element analysis, it provides an effective basis for maintenance and the damage prediction
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Jeon, Hyung Jin, Bo Kyoung Choi, Seo In Hwang, Soo Hyun Kim, Gil Jung Kim, Jae Chan Park, Zung Yoon Yang, and Kwang Yeon Hwang. "Optimization for Simultaneous Removal of Product/Process-Related Impurities of Peptide Fc-Fusion Protein Using Cation Exchange Chromatography." Processes 10, no. 11 (November 11, 2022): 2359. http://dx.doi.org/10.3390/pr10112359.
Повний текст джерелаАнотація:
Fc fusion proteins are used as therapeutic agents with unique structures by combining the Fc domain of an antibody with other active proteins, cytokines, and enzymes. Peptide Fc-fusion proteins are complex fusion molecules that possess a structure different from that of monoclonal antibodies (mAbs) and are difficult to express, thereby affecting their quality. Many product/process-related impurities generated during the production of peptide Fc-fusion proteins pose a risk to the robustness of pre-existing three-column platforms for the purification of mAbs. Thus, we first evaluated the effect of pH, conductivity, and dynamic binding capacity (DBC; g of product per liter of resin) on the separation of host cell protein (HCP) and high molecular weight (HMW) and low molecular weight (LMW) proteins in strong cation exchange chromatography and then established an operating range using the design of experiments (DoE). Based on our studies, the optimal removal rates of HCP and HMW were achieved under the following conditions: 8 CV of wash buffer, 20–23 g/L of resin DBC, and an elution buffer conductivity of 63–66 mS/cm. The conductivity of the wash buffer used to remove the LMW was 50 mS/cm. In addition, reproducibility was confirmed by scaling up two batches using the Fractogel® EMD SO3− (M) resin. As a result of confirming with a validated test method in all batches, >55% yield, >98.2% purity, and >27% HCP reduction rate were satisfied. The cation exchanger exhibited an acceptable step yield and effectively reduced product/process-related impurities within the established range.
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Gao, Fei, Fang Peng Li, Qiong Wu, and Mei Ting Jiang. "Research and Utilization of Downhole Dynamic Corrosion Test Device." Applied Mechanics and Materials 397-400 (September 2013): 489–93. http://dx.doi.org/10.4028/www.scientific.net/amm.397-400.489.
Повний текст джерелаАнотація:
With the lengthen of the production time continuously, and the adjustment and implementation of development programs constantly, the situation of Jiangsu Oil field well casing will become worse, even damaged gradually, while corrosion is one of the main factors to cause casing leakage in Jiangsu Oil field. In order to study the corrosion mechanism and influencing factors, we developed downhole dynamic simulation experiment device. The device is mainly composed of the recycle loop system, temperature control system, pressure control system, the main riser, and the buffer vessel. It implements the control of factors impact on the oil casing corrosion such as temperature, partial pressure, flow rate etc and helps us study the corrosion behavior of downhole tubing and casing. The results of weightlessness and electron microscope scanning show that the flow velocity and flow pattern is the main factors of maximum casing corrosion near the oil pump suction rate, and the local corrosion by CO2 is given priority to, this is consistent with the situation of field casing corrosion. It also shows that this experimental device has the advantages of reasonable structure, stable and reliable performance, easy operation, strong simulation and practicality.
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Bai, Bingtao, Lurui Xia, and Sen Li. "Design and dynamics simulation of axial radial double locking satellite docking mechanism." Journal of Physics: Conference Series 2569, no. 1 (August 1, 2023): 012020. http://dx.doi.org/10.1088/1742-6596/2569/1/012020.
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Abstract Aiming at the docking requirements of small satellites in orbit service, an axial, radial double-locking satellite docking mechanism was designed to realize the docking and separation of small satellites. Capture docking using the butt bar and the groove. The mechanism possesses multiple advantages, such as simple structure and fast response. A dynamic model considering contact, collision, buffering, and friction was established, and ADAMS software simulated the docking process. Apart from that, the dynamics and motion data of the mechanism were obtained. As revealed by the results, under the initial conditions of the general light and small docking mechanism, the mechanism can achieve the set task and complete the docking with a small collision force. What’s more, the buffer device can absorb 85.5% of the energy of the satellite, and the mechanism has a certain attitude correction ability. Altogether, this exploration can provide a reference for designing satellite docking mechanisms and formulating a docking strategy in the future.
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Ninomiya, Hideki, Tomomichi Kato, Lea Végh, and Lan Wu. "Modeling of non-structural carbohydrate dynamics by the spatially explicit individual-based dynamic global vegetation model SEIB-DGVM (SEIB-DGVM-NSC version 1.0)." Geoscientific Model Development 16, no. 14 (July 25, 2023): 4155–70. http://dx.doi.org/10.5194/gmd-16-4155-2023.
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Abstract. Forest dynamics need to be considered when estimating the global carbon budget. The alteration of forest structure and function under a changing climate and expanding human activity could lead to a reduction of forest canopy cover and a spread of lower-biomass ecosystems in warm and dry regions. A non-structural carbohydrate (NSC) acts as a storage buffer between carbon supplied by assimilation and carbon consumed by, inter alia, respiration, reproduction, and pests. Estimation of NSC concentrations in a tree is very important for accurate projection of future forest dynamics. We developed a new NSC module for incorporation into a spatially explicit individual-based dynamic global vegetation model (SEIB-DGVM) to validate the simulated NSC dynamics with observations. NSC pools were simulated in three plant organs: leaves, trunk, and roots. The seasonal dynamics of the NSCs varied among plant species, and the sizes of the NSC pools inferred from observations differed between the boreal, temperate, and tropical climates. The NSC models were therefore validated for each of the three climatic regions at both point and global scales to assess the performance of the models. The modeled NSCs showed good agreement in seasonality with the observed NSCs at four sites – Canada (boreal), Austria and Switzerland (temperate), and Panama (tropical) – and in mean values for three climate zones derived from the global NSC dataset. The SEIB-DGVM-NSC version 1.0 is expected to enable simulation of biome shifts caused by the changes in NSC dynamics worldwide. These dynamics will contribute to changes in not only the global carbon cycle but also in forest structure and demography at a global scale.
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Zhang, Ri Hong, Jun Xia Shi, and Ji Wen Hu. "Finite Element Mechanical Analysis of Cushion Seals in High Speed Pneumatic Cylinder." Applied Mechanics and Materials 275-277 (January 2013): 44–50. http://dx.doi.org/10.4028/www.scientific.net/amm.275-277.44.
Повний текст джерелаАнотація:
The design of pneumatic cylinder seals is in accordance with the theory of fluid elastic tight seal. The sealing mechanism depends on the contact force which is created by the interference of initial elastic seal assembly and the sealing force which is created by the working fluid acting on the elastomeric material. In the high-speed pneumatic cylinder, the buffer structure enables the piston decelerates rapidly and stops stably. When the buffer stage begins, it will produce a strong dynamic contact between the cushion seals and the cushion spear. After the failure of cushion seals happen，the buffering capacity will be declined sharply. Therefore, the mechanical properties analysis of the cushion seals becomes very important. The material characteristics and the magnitude of interference of the cushion seals as well as the operating speed of the cylinder piston have a large impact on the life of the cushion seals. In this paper, based on the finite element analysis software ABAQUS, it provides certain reference value for the cushion seals material selection and structural parameters.
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Stalder, Peter. "A Macro Disequilibrium Model for Switzerland." Recherches économiques de Louvain 57, no. 2 (1991): 125–58. http://dx.doi.org/10.1017/s0770451800055585.
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SummaryThis paper presents a disequilibrium model for Switzerland, focusing on the production sector and the associated spillover effects. Firms' decisions on output supply, labor demand and investment are analysed on basis of a vintage approach, involving pressure of demand, profitability and relative prices as determinants. Macro relationships are derived by aggregating over micro markets on which regimes are allowed to differ. In the resulting nonlinear macro structure the response of output and employment to demand-side and supply-side factors varies through the cycle, depending on the regime-mix (measured by survey data). Inventories and unfilled orders act as buffer stocks, modifying the dynamic link between current demand and output.
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Borel, Andžej. "DEVELOPMENT AND INVESTIGATION OF INPUT AMPLIFIER FOR THE OSCILOSCOPE." Mokslas - Lietuvos ateitis 12 (January 20, 2020): 1–5. http://dx.doi.org/10.3846/mla.2020.11420.
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Digital oscilloscope’s structure has analog signal acquisition circuit, which transforms signal’s amplitude to fit ADC dynamic range. This circuit is commonly called oscilloscope’s vertical or front-end amplifier. Difficulty in designing front-end amplifiers in GHz range largely affects higher frequency range oscilloscope’s price. This work is focused on designing a front-end amplifier using discrete and openly sold components. We propose a design for attenuator, buffer, variable gain circuits. Amplifier’s prototype is designed. Main characteristics of the amplifier were measured. Measured bandwidth is 3 GHz. Amplifier’s gain and attenuation can support vertical scale sensitivity range from 10 mV/div to 1 V/div. Step response distortion is under 10 %. SMD and PTH relay model attenuators were evaluated. In this paper we review oscilloscope’s front-end purpose and structure. We review amplifiers design and provide the results of experimental measurements.
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Yüksek, K., M. Alparslan, and E. Mendi. "Effective 3-D surface modeling for geographic information systems." Natural Hazards and Earth System Sciences 16, no. 1 (January 18, 2016): 123–33. http://dx.doi.org/10.5194/nhess-16-123-2016.
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Abstract. In this work, we propose a dynamic, flexible and interactive urban digital terrain platform with spatial data and query processing capabilities of geographic information systems, multimedia database functionality and graphical modeling infrastructure. A new data element, called Geo-Node, which stores image, spatial data and 3-D CAD objects is developed using an efficient data structure. The system effectively handles data transfer of Geo-Nodes between main memory and secondary storage with an optimized directional replacement policy (DRP) based buffer management scheme. Polyhedron structures are used in digital surface modeling and smoothing process is performed by interpolation. The experimental results show that our framework achieves high performance and works effectively with urban scenes independent from the amount of spatial data and image size. The proposed platform may contribute to the development of various applications such as Web GIS systems based on 3-D graphics standards (e.g., X3-D and VRML) and services which integrate multi-dimensional spatial information and satellite/aerial imagery.
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Yüksek, K., M. Alparslan, and E. Mendi. "Effective 3-D surface modeling for geographic information systems." Natural Hazards and Earth System Sciences Discussions 1, no. 6 (November 5, 2013): 6093–131. http://dx.doi.org/10.5194/nhessd-1-6093-2013.
Повний текст джерелаАнотація:
Abstract. In this work, we propose a dynamic, flexible and interactive urban digital terrain platform (DTP) with spatial data and query processing capabilities of Geographic Information Systems (GIS), multimedia database functionality and graphical modeling infrastructure. A new data element, called Geo-Node, which stores image, spatial data and 3-D CAD objects is developed using an efficient data structure. The system effectively handles data transfer of Geo-Nodes between main memory and secondary storage with an optimized Directional Replacement Policy (DRP) based buffer management scheme. Polyhedron structures are used in Digital Surface Modeling (DSM) and smoothing process is performed by interpolation. The experimental results show that our framework achieves high performance and works effectively with urban scenes independent from the amount of spatial data and image size. The proposed platform may contribute to the development of various applications such as Web GIS systems based on 3-D graphics standards (e.g. X3-D and VRML) and services which integrate multi-dimensional spatial information and satellite/aerial imagery.
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Ballesteros, Miguel, Chris Dyer, Yoav Goldberg, and Noah A. Smith. "Greedy Transition-Based Dependency Parsing with Stack LSTMs." Computational Linguistics 43, no. 2 (June 2017): 311–47. http://dx.doi.org/10.1162/coli_a_00285.
Повний текст джерелаАнотація:
We introduce a greedy transition-based parser that learns to represent parser states using recurrent neural networks. Our primary innovation that enables us to do this efficiently is a new control structure for sequential neural networks—the stack long short-term memory unit (LSTM). Like the conventional stack data structures used in transition-based parsers, elements can be pushed to or popped from the top of the stack in constant time, but, in addition, an LSTM maintains a continuous space embedding of the stack contents. Our model captures three facets of the parser's state: (i) unbounded look-ahead into the buffer of incoming words, (ii) the complete history of transition actions taken by the parser, and (iii) the complete contents of the stack of partially built tree fragments, including their internal structures. In addition, we compare two different word representations: (i) standard word vectors based on look-up tables and (ii) character-based models of words. Although standard word embedding models work well in all languages, the character-based models improve the handling of out-of-vocabulary words, particularly in morphologically rich languages. Finally, we discuss the use of dynamic oracles in training the parser. During training, dynamic oracles alternate between sampling parser states from the training data and from the model as it is being learned, making the model more robust to the kinds of errors that will be made at test time. Training our model with dynamic oracles yields a linear-time greedy parser with very competitive performance.
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Leineweber, Kirsten, Alexander Schulz, and Gary A. Thompson. "Dynamic transitions in the translocated phloem filament protein." Functional Plant Biology 27, no. 9 (2000): 733. http://dx.doi.org/10.1071/pp99161.
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This paper originates from a presentation at the International Conference on Assimilate Transport and Partitioning, Newcastle, NSW, August 1999 Recent evidence suggests that the P-proteins of Cucurbita maxima exist in at least two structural states: large polymers that are immobilized in individual sieve elements and small polymers or individual subunits that are translocated over long distances. We investigated variation in the structure of the phloem filament protein (phloem protein 1 or PP1) to determine the translocated form of the protein and its relationship to the polymerized state. It was demonstrated that the stability, folding state and assembly of the phloem filament protein rely on distinct intramolecular disulfide bonds. Acid trapping experiments combined with intergeneric grafts revealed that the phloem filament protein is translocated as an 88 kDa globular protein. By altering the pH of the collection buffer (pH 2–10), four individual conformational isoforms of PP1 with molecular masses of 81, 83, 85 and 88 kDa were consistently observed. The 81 kDa isoform represents the totally reduced phloem filament protein, the 83 and 85 kDa isoforms folding intermediates, and the 88 kDa its native soluble translocated form. The 83 and 85 kDa folding intermediates are susceptible to aggregation causing the gelation and formation of P-protein filaments in oxidized phloem sap. In contrast to the 88 kDa globular transport form, the 81, 83 and 85 kDa isoforms possibly exhibit lower stability, and therefore a higher sensitivity to proteolytic digestion.
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Falke, Sven, Christian Feiler, Henry Chapman, and Iosifina Sarrou. "Crystal structures of native cytochrome c 6 from Thermosynechococcus elongatus in two different space groups and implications for its oligomerization." Acta Crystallographica Section F Structural Biology Communications 76, no. 9 (August 20, 2020): 444–52. http://dx.doi.org/10.1107/s2053230x20010249.
Повний текст джерелаАнотація:
Native cytochrome c 6 was purified from an extract of strain BP-1 of the thermophilic cyanobacterium Thermosynechococcus elongatus. The protein was crystallized, and with only slight modifications of the buffer and vapour-diffusion conditions two different space groups were observed, namely H3 and C2. Both crystal structures were solved; they contained three and six molecules per asymmetric unit and were refined to 1.7 and 2.25 Å resolution, respectively. To date, the structure of native cytochrome c 6 from T. elongatus has only been reported as a monomer using NMR spectroscopy, i.e. without addressing putative oligomerization, and related structures have only previously been solved using X-ray crystallography after recombinant gene overexpression in Escherichia coli. The reported space groups of related cyanobacterial cytochrome c 6 structures differ from those reported here. Interestingly, the protein–protein interfaces that were observed utilizing X-ray crystallography could also explain homo-oligomerization in solution; specifically, trimerization is indicated by infra-red dynamic light scattering and blue native gel electrophoresis in solution. Trimers were also detected by mass spectrometry. Furthermore, there is an indication of post-translational methylation in the crystal structure. Additionally, the possibility of modifying the crystal size and the redox activity in the context of photosynthesis is shaping the investigated cytochrome as a highly suitable model protein for advanced serial crystallography at highly brilliant X-ray free-electron laser sources.
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Xu, Susan H., and Y. Quennel Zhao. "Dynamic routing and jockeying controls in a two-station queueing system." Advances in Applied Probability 28, no. 4 (December 1996): 1201–26. http://dx.doi.org/10.2307/1428170.
Повний текст джерелаАнотація:
This paper studies optimal routing and jockeying policies in a two-station parallel queueing system. It is assumed that jobs arrive to the system in a Poisson stream with rate λand are routed to one of two parallel stations. Each station has a single server and a buffer of infinite capacity. The service times are exponential with server-dependent rates, μ1 and μ2. Jockeying between stations is permitted. The jockeying cost is cij when a job in station i jockeys to station j, i ≠ j. There is no cost when a new job joins either station. The holding cost in station j is hj, h1 ≦ h2, per job per unit time. We characterize the structure of the dynamic routing and jockeying policies that minimize the expected total (holding plus jockeying) cost, for both discounted and long-run average cost criteria. We show that the optimal routing and jockeying controls are described by three monotonically non-decreasing functions. We study the properties of these control functions, their relationships, and their asymptotic behavior. We show that some well-known queueing control models, such as optimal routing to symmetric and asymmetric queues, preemptive or non-preemptive scheduling on homogeneous or heterogeneous servers, are special cases of our system.
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Xu, Susan H., and Y. Quennel Zhao. "Dynamic routing and jockeying controls in a two-station queueing system." Advances in Applied Probability 28, no. 04 (December 1996): 1201–26. http://dx.doi.org/10.1017/s0001867800027610.
Повний текст джерелаАнотація:
This paper studies optimal routing and jockeying policies in a two-station parallel queueing system. It is assumed that jobs arrive to the system in a Poisson stream with rate λand are routed to one of two parallel stations. Each station has a single server and a buffer of infinite capacity. The service times are exponential with server-dependent rates, μ 1 and μ 2. Jockeying between stations is permitted. The jockeying cost is cij when a job in station i jockeys to station j, i ≠ j. There is no cost when a new job joins either station. The holding cost in station j is hj, h 1 ≦ h 2, per job per unit time. We characterize the structure of the dynamic routing and jockeying policies that minimize the expected total (holding plus jockeying) cost, for both discounted and long-run average cost criteria. We show that the optimal routing and jockeying controls are described by three monotonically non-decreasing functions. We study the properties of these control functions, their relationships, and their asymptotic behavior. We show that some well-known queueing control models, such as optimal routing to symmetric and asymmetric queues, preemptive or non-preemptive scheduling on homogeneous or heterogeneous servers, are special cases of our system.