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Autore: Grafiati

Pubblicato: 8 giugno 2024

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1

Gianvittorio, Stefano, Domenica Tonelli e Andreas Lesch. "Print-Light-Synthesis for Single-Step Metal Nanoparticle Synthesis and Patterned Electrode Production". Nanomaterials 13, n. 13 (23 giugno 2023): 1915. http://dx.doi.org/10.3390/nano13131915.

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The fabrication of thin-film electrodes, which contain metal nanoparticles and nanostructures for applications in electrochemical sensing as well as energy conversion and storage, is often based on multi-step procedures that include two main passages: (i) the synthesis and purification of nanomaterials and (ii) the fabrication of thin films by coating electrode supports with these nanomaterials. The patterning and miniaturization of thin film electrodes generally require masks or advanced patterning instrumentation. In recent years, various approaches have been presented to integrate the spatially resolved deposition of metal precursor solutions and the rapid conversion of the precursors into metal nanoparticles. To achieve the latter, high intensity light irradiation has, in particular, become suitable as it enables the photochemical, photocatalytical, and photothermal conversion of the precursors during or slightly after the precursor deposition. The conversion of the metal precursors directly on the target substrates can make the use of capping and stabilizing agents obsolete. This review focuses on hybrid platforms that comprise digital metal precursor ink printing and high intensity light irradiation for inducing metal precursor conversions into patterned metal and alloy nanoparticles. The combination of the two methods has recently been named Print-Light-Synthesis by a group of collaborators and is characterized by its sustainability in terms of low material consumption, low material waste, and reduced synthesis steps. It provides high control of precursor loading and light irradiation, both affecting and improving the fabrication of thin film electrodes.

2

Hase, Takashi, Ryusuke Kita, Kenichi Kawaguchi, Takeshi Koga e Tadataka Morishita. "Synthesis of single phase YBa2Cu3O7−x thin films from a Y-Ba-Cu metallic precursor by a low-temperature annealing". Journal of Materials Research 9, n. 6 (giugno 1994): 1337–42. http://dx.doi.org/10.1557/jmr.1994.1337.

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YBa2Cu3O7−x (YBCO) superconducting thin films that show no x-ray diffraction peaks due to any other non-superconducting phases have been synthesized by annealing Y-Ba-Cu-O amorphous precursors at 750 °C. The Y-Ba-Cu-O precursors have been fabricated by oxidizing Y-Ba-Cu metallic precursors coevaporated from Y, Ba, and Cu metallic sources under ultrahigh vacuum conditions. Crystallization behavior from the Y-Ba-Cu-O precursor to YBCO films drastically depends on an oxidation temperature for the Y-Ba-Cu metallic precursor. YBCO thin film synthesized from the precursor oxidized at an optimum temperature shows a zero resistance temperature of over 80 K and a very smooth surface.

3

Guerette, Michael, Timothy A. Strobel, Haidong Zhang, Stephen Juhl, Nasim Alem, Konstantin Lokshin, Lakshmi Krishna e P. Craig Taylor. "Advanced Synthesis of Na4Si24". MRS Advances 3, n. 25 (2018): 1427–33. http://dx.doi.org/10.1557/adv.2018.44.

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ABSTRACTThe recently discovered orthorhombic allotrope of silicon, Si24, is an exciting prospective material for the future of solar energy due to a quasi-direct bandgap near 1.3 eV, coupled with the abundance and environmental stability of silicon. Synthesized via precursor Na4Si24at high temperature and pressure (∼850 °C, 9 GPa), typical synthesis results have yielded polycrystalline samples with crystallites on the order of 20 μm. Several approaches to increase the crystal size have yielded success, including in-situ thermal spikes and refined selection of the starting materials. Microstructural analysis suggests that coherency exists between diamond silicon (d-Si) and Na4Si24. This hypothesis has led to the successful attempts at single crystal synthesis by selecting large crystals of d-Si along with metallic Na as the precursors rather than powdered and mixed precursor material. The new synthesis approach has yielded single crystals of Na4Si24greater than 100 μm. These results represent a breakthrough in synthesis that enables further characterization and utility. The promise of Si24for the future of solar energy generation and efficient electronics is strengthened through these advances in synthesis.

4

Malik, M. A., M. Afzaal, P. O'Brien, U. Bangert e B. Hamilton. "Single molecular precursor for synthesis of GaAs nanoparticles". Materials Science and Technology 20, n. 8 (agosto 2004): 959–63. http://dx.doi.org/10.1179/026708304225019786.

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5

Bocharova, Irina V., e Galina B. Kunshina. "Study of ceramic and glass-ceramic solid electrolyte Li1,5Al0,5Ge1,5(PO4)3 properties obtained from oxalate and citrate precursors". Transactions of the Kоla Science Centre of RAS. Series: Engineering Sciences 13, n. 1/2022 (27 dicembre 2022): 26–32. http://dx.doi.org/10.37614/2949-1215.2022.13.1.004.

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The synthesis of lithium conducting solid electrolyte Li1.5Al0.5Ge1.5(PO4)3 (LAGP) by liquid-phase method from oxalate and citrate precursors is investigated. The samples were characterized by XRD, DSC / TG, IR, impedance spectroscopy and potentiostatic chronoamperometry. It was found that the formation of a single - phase LAGP from an oxalate precursor occurs at a lower temperature (600–650 °C) and is preferable compared to the synthesis of LAGP from a citrate precursor. The ionic conductivity of the electrolyte was 4,2 · 10-4 S / cm, the electronic conductivity did not exceed 2 · 10-10 S / cm, the decomposition potential was 3.8 V.

6

Liang, Li, Meihua Zhu, Le Chen, Caijun Zhong, Yiming Yang, Ting Wu, Heli Wang, Izumi Kumakiri, Xiangshu Chen e Hidetoshi Kita. "Single Gas Permeance Performance of High Silica SSZ-13 Zeolite Membranes". Membranes 8, n. 3 (13 luglio 2018): 43. http://dx.doi.org/10.3390/membranes8030043.

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Continuous and high silica SSZ-13 zeolite membranes were prepared on porous mullite supports from high SiO2/Al2O3 ratio or aluminum-free precursor synthesis gel. Single gas permeance (CO2 and CH4) of the high silica SSZ-13 zeolite membrane was decreased with the SiO2/Al2O3 ratio in the precursor synthesis gel, while the ideal CO2/CH4 selectivity of the membrane was gradually increased. Moreover, effects of synthesis conditions (such as H2O/SiO2 and RNOH/SiO2 ratios of precursor synthesis gel, crystallization time) on the single gas permeance performance of high silica SSZ-13 zeolite membranes were studied in detail. Medium H2O/SiO2 and RNOH/SiO2 ratios in the initial synthesis gel were crucial to prepare the good CO2 perm-selective SSZ-13 zeolite membrane. When the molar composition of precursor synthesis gel, crystallization temperature and time were 1.0 SiO2: 0.1 Na2O: 0.1 TMAdaOH: 80 H2O, 160 °C and 48 h, CO2 permeance and ideal CO2/CH4 selectivity of the SSZ-13 zeolite membrane were 0.98 × 10−7 mol/(m2·s·Pa) and 47 at 25 °C and 0.4 MPa. In addition, the SiO2/Al2O3 ratio of the corresponding SSZ-13 zeolite was 410 by X-ray fluorescence spectroscopy.

7

Cha, Sang Ho. "Synthesis of Single-Crystalline Gold Nanosheet Having Multilayer Structure under the Polymeric Bulk Condition". Applied Mechanics and Materials 548-549 (aprile 2014): 301–4. http://dx.doi.org/10.4028/www.scientific.net/amm.548-549.301.

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A novel synthetic approach to ultrathin (< 5 nm) multilayered single crystalline gold nanosheets using amphiphilic comb-like polymer as template was presented. The poly (oxyethylene) containing decyl-tri (oxyethylene) amphiphile as well as the thioether linking group in the side chain was synthesized via polymer analogous reaction. The polymer and the gold precursor, LiAuCl4, were mixed and dried to afford a homogeneous complex. The gold precursors were reduced to gold crystals by photoreduction using long wave UV light (> 350 nm). The gold nanosheets with multilayered structure, where the layer spacing is about 3.6 nm, were obtained after 24 h. The formation of the multilayered nanosheets is due to the layered structure of the gold complex of the polymer and precursor.

8

Devi, P. Sujatha, Yongjae Lee, Joshua Margolis, John B. Parise, Sanjay Sampath, Herbert Herman e Jonathan C. Hanson. "Comparison of citrate–nitrate gel combustion and precursor plasma spray processes for the synthesis of yttrium aluminum garnet". Journal of Materials Research 17, n. 11 (novembre 2002): 2846–51. http://dx.doi.org/10.1557/jmr.2002.0413.

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The influence of synthesis conditions on the formation of yttrium aluminum garnet (YAG) powders starting from the same solution precursors was investigated by employing a citrate–nitrate gel combustion process and a precursor plasma spraying technique. YAG powders were formed at ≥500 °C, through the citrate–nitrate gel combustion process, without any intermediate phase formation. Time-resolved x-ray experiments were performed for the first time on these citrate–nitrate precursor materials to understand their mode of decomposition. The in situ data confirmed a single-step conversion to YAG from the precursor powder without any intermediate phase formation. Ex situ experiments also produced similar results. However, the use of the same citrate–nitrate precursor solution as a liquid feedstock material in the precursor plasma spraying technique revealed an entirely different transformation mechanism to YAG through intermediate phases like H–YalO3 and O–YalO3.

9

Brune, Veronika, Nidal Raydan, Anja Sutorius, Fabian Hartl, Bhagyesh Purohit, Sweta Gahlot, Pascal Bargiela et al. "Single source precursor route to nanometric tin chalcogenides". Dalton Transactions 50, n. 46 (2021): 17346–60. http://dx.doi.org/10.1039/d1dt02964a.

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10

Stanton, C., e R. Wallin. "Processing and trafficking of clotting factor X in the secretory pathway. Effects of warfarin". Biochemical Journal 284, n. 1 (15 maggio 1992): 25–31. http://dx.doi.org/10.1042/bj2840025.

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Clotting factor X undergoes several post-translational processing steps in the liver before the protein appears in blood as the mature two-chain zymogen. In this study we have followed the factor X precursor through the secretory pathway in rat liver in order to identify the site for proteolytic processing of the precursor into a two-chain form and the site for warfarin inhibition of precursor trafficking within the pathway. Isolated rat liver Golgi apparatus was shown to harbour two single-chains of factor X precursors of 70 and 74 kDa and the heavy (50 kDa) and light chains of factor X. It was demonstrated that the two-chain factor X form was produced from a late processing form of the factor X precursor, which indicated that the site for proteolytic conversion to a two-chain form was in the trans-Golgi compartment. The 70 and 74 kDa single-chain precursors and also the light chain of the two-chain form were shown to contain the factor X propeptide which is normally removed before the coagulation factor appears in blood. The data demonstrate that intra-chain cleavage of a single chain factor X precursor in the trans-Golgi compartment can precede release of the propeptide. Warfarin was shown to affect trafficking of the factor X precursor between the endoplasmic reticulum (ER) and the Golgi apparatus. The data suggest a link between vitamin K-dependent gamma-carboxylation of the precursor and its exit from the ER. Warfarin administration resulted in accumulation of factor X precursors associated with the ER membrane. These precursors appear to be stabilized from intracellular degradation while in the ER. In contrast to the large increase in the factor X precursor concentration in the ER membrane, there was no change in the prothrombin precursor concentration as a result of warfarin action on the liver. However, intracellular turnover of the microsomal prothrombin precursor pool in warfarin-treated rats resulted in a pool of less negatively charged proteins, indicating ongoing protein synthesis but inhibition of gamma-carboxylation. The data are consistent with previous findings [Wallin & Martin (1988) J. Biol. Chem. 263, 9994-10001] suggesting that prothrombin and factor X are processed differently by the vitamin K-dependent carboxylase in the ER membrane.

11

Rai, S., e R. Kothari. "Synthesis and Spectroscopic Characterization of Zinc Sulphide nanoparticles using Microwave irradiation of Zinc complex of Thiosemicarbazone ligand as a Single Molecular precursor : Pharmacological activities". Digest Journal of Nanomaterials and Biostructures 18, n. 1 (gennaio 2023): 31–45. http://dx.doi.org/10.15251/djnb.2023.181.31.

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Single molecular precursors are appropriate starting materials for synthesis of semiconductor nanoparticles (NPs), which allow for the control of atomic ratio, monodispersity, composition and particle size of nanoscaled metallic sulfide nanoparticles. In the present study, we have reported the synthesis of nanostructured chalcogenides pharmacologically active active zinc sulfide nanoparticles (ZnS NPs) using Zn (II) ion inserted thiosemicarbazone ligand as a single molecular precursor .The precursors were thermally pyrolysized using high energy microwave radiations to obtain very fine ZnS nanoparticles. In this synthesis, we use DMSO as a nonpolar solvent for the synthesis of all compounds. The heating of Zinc complex in the non- aqueous environment of DMSO plays a very crucial role in decreasing reaction time, reducing the chances of side reactions and proper conversion of Zn complex into ZnS nanoparticles. In this reaction Zn complex of thiosemicarbazone ligand provides both Zn2+ and S2- ions for synthesis of ZnS nanoparticles. The microwave synthesis of ZnS NPs from Zn complex is a very simple, fast, highly effective, efficient and low cost method. All synthesized compounds were characterized by various structural, electronic, vibrational, optical, morphological and pharmacological characterizations. The prepared ZnS NPs were found to crystallize in cubic phase, which generally forms at low temperatures, with the dimensions dependent upon the molar ratio of molecular precursors used. Synthesized ZnS nanomaterials had surface sulfur vacancies that extend their absorption spectra towards the visible region and decreased the bond gap. This allowed ZnS nanoparticles to demonstrate various pharmacological activities like antibacterial, antioxidant and anti-inflammatory activities under normal conditions. Powered X-ray diffraction studies confirms the formation of well -defined equispaced crystalline ZnS NPS. TEM and FE SEM microscopic studies confirmed the elongated tubules structure of ZnS NPs with an average particle size of 60 nm. Sharpe electronic absorption band at 390 nm indicates the synthesis of good quality ZnS NPs. The FT-IR spectral studies confirmed the presence of Zn-S stretching, N-H bending and C=N stretching, vibrations in molecular precursor as Zn(II) complex. The thermal analysis of molecular precursor was performed to investigate the thermal stability of zinc complex. The Zn complex was stable up-to 3800 c. All synthesized compounds demonstrated excellent pharmacological activities like antibacterial, antioxidant and antiinflammatory activities as compared to standards used in analysis of compounds. The microwave synthesis of ZnS nanoparticles via single molecular precursor in proper stoichiometric ratios is an excellent and an efficient method for synthesizing highly effective bioactive agents which can be considered as good drug candidate for the treatment of various diseases in future

12

Trusty, P. A., K. C. Chan e C. B. Ponton. "Synthesis of sinteractive single-phase microstructure yttrium disilicate precursor powder using hydrothermal processing". Journal of Materials Research 13, n. 11 (novembre 1998): 3135–43. http://dx.doi.org/10.1557/jmr.1998.0426.

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This paper is the first report of the synthesis of a sinteractive single-phase microstructure yttrium disilicate precursor powder using hydrothermal processing. The effect of the pH of the precursor chemicals on the ease of formation of a single-phase material was investigated using x-ray diffraction, TEM, and SEM. Under very acidic conditions (pH 1), the formation of yttrium chloride, in addition to the yttrium disilicate precursors, produced a powder that absorbed moisture, did not sinter well, and produced a two-phase interpenetrating microstructure after sintering. At pH 6, yttrium chloride no longer formed, but the interpenetrating network persisted after sintering. Only under basic conditions (pH 10) did single-phase yttrium disilicate form after sintering. This work is noteworthy because the calcination time of 1 h required for the formation of this ceramic at 1050 °C is over an order of magnitude lower than the calcination times of over 100 h required when calcined in the temperature range 900 °C to 1150 °C, as reported previously by other workers.

13

Douglas, F. J., D. A. MacLaren, N. Maclean, I. Andreu, F. J. Kettles, F. Tuna, C. C. Berry, M. Castro e M. Murrie. "Gadolinium-doped magnetite nanoparticles from a single-source precursor". RSC Advances 6, n. 78 (2016): 74500–74505. http://dx.doi.org/10.1039/c6ra18095g.

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Purkait, Tapas K., Anindya K. Swarnakar, Glenda B. De Los Reyes, Frank A. Hegmann, Eric Rivard e Jonathan G. C. Veinot. "One-pot synthesis of functionalized germanium nanocrystals from a single source precursor". Nanoscale 7, n. 6 (2015): 2241–44. http://dx.doi.org/10.1039/c4nr05125d.

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Tsyganov, D., N. Bundaleska, J. Henriques, E. Felizardo, A. Dias, M. Abrashev, J. Kissovski, A. M. Botelho do Rego, A. M. Ferraria e E. Tatarova. "Simultaneous Synthesis and Nitrogen Doping of Free-Standing Graphene Applying Microwave Plasma". Materials 13, n. 18 (22 settembre 2020): 4213. http://dx.doi.org/10.3390/ma13184213.

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An experimental and theoretical investigation on microwave plasma-based synthesis of free-standing N-graphene, i.e., nitrogen-doped graphene, was further extended using ethanol and nitrogen gas as precursors. The in situ assembly of N-graphene is a single-step method, based on the introduction of N-containing precursor together with carbon precursor in the reactive microwave plasma environment at atmospheric pressure conditions. A previously developed theoretical model was updated to account for the new reactor geometry and the nitrogen precursor employed. The theoretical predictions of the model are in good agreement with all experimental data and assist in deeper understanding of the complicated physical and chemical process in microwave plasma. Optical Emission Spectroscopy was used to detect the emission of plasma-generated ‘‘building units’’ and to determine the gas temperature. The outlet gas was analyzed by Fourier-Transform Infrared Spectroscopy to detect the generated gaseous by-products. The synthesized N-graphene was characterized by Scanning Electron Microscopy, Raman, and X-ray photoelectron spectroscopies.

16

Makin, Fadiyah, Dalal Alzahrani, Firoz Alam, Floriana Tuna e David J. Lewis. "Testing the Efficacy of the Synthesis of Iron Antimony Sulfide Powders from Single Source Precursors". Inorganics 9, n. 8 (2 agosto 2021): 61. http://dx.doi.org/10.3390/inorganics9080061.

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The antimony-iron sulfide system in general does not produce alloys below 540 °C from traditional solid-state methods. However, single source precursors have been known to produce unexpected products that arise from kinetically trapped polymorphs. In this paper, we test the efficacy of this approach toward the Fe-Sb-S system. Antimony and iron diethyldithiocarbamate complexes of the form Sb[S2CN(Et2)]3 (1) and Fe[S2CN(Et2)]3 (2) were synthesised, characterised, and used as single-source precursors for the preparation of Sb2S3, FexSy, and mixed iron antimony sulfide Sb2(1−x)Fe2xS3 (0 ≥ x ≥ 1) powders using the solvent-less thermolysis method at different temperatures ranging from 300 to 475 °C. The effect of different mole fractions of the iron precursor was evaluated on morphology, shape, and optical and magnetic properties of Sb2(1−x)Fe2xS3 (0 ≥ x ≥ 1). The obtained powders were characterized by X-ray diffraction (XRD), Raman spectroscopy scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, magnetometer measurement, and UV/vis/NIR spectroscopy. The results demonstrated that the crystalline structure, morphology, and elemental composition of the samples changed with the mole fraction of the precursor. There was significant phase separation between Sb and Fe sulfides noted from EDX spectroscopic mapping, yet an optoelectronic study monitoring the direct band gap energy of antimony sulfide shows that the band gap energy increases as a function of Fe content, which suggests limited alloying is possible from the single source route.

17

Sugathan, Vipinraj, Biplab Ghosh, Pandinhare C. Harikesh, Vishal Kotha, Parth Vashishtha, Teddy Salim, Aswani Yella e Nripan Mathews. "Synthesis of bismuth sulphoiodide thin films from single precursor solution". Solar Energy 230 (dicembre 2021): 714–20. http://dx.doi.org/10.1016/j.solener.2021.10.041.

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Chamberlin, A. Richard, e John Y. L. Chung. "Enantioselective synthesis of seven pyrrolizidine diols from a single precursor". Journal of Organic Chemistry 50, n. 23 (novembre 1985): 4425–31. http://dx.doi.org/10.1021/jo00223a002.

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19

Mirkovic, Tihana, Margaret A. Hines, P. Sreekumari Nair e Gregory D. Scholes. "Single-Source Precursor Route for the Synthesis of EuS Nanocrystals". Chemistry of Materials 17, n. 13 (giugno 2005): 3451–56. http://dx.doi.org/10.1021/cm048064m.

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Zhao, Yiming, Freddy T. Rabouw, Celso de Mello Donegá, Andries Meijerink e Cornelis A. van Walree. "Single-source precursor synthesis of colloidal CaS and SrS nanocrystals". Materials Letters 80 (agosto 2012): 75–77. http://dx.doi.org/10.1016/j.matlet.2012.04.066.

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Long, Xin, Changwei Shao, Hao Wang e Jun Wang. "Single-source-precursor synthesis of SiBNC-Zr ceramic nanocomposites fibers". Ceramics International 42, n. 16 (dicembre 2016): 19206–11. http://dx.doi.org/10.1016/j.ceramint.2016.09.084.

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Sobhani, Azam, Masoud Salavati-Niasari e S. Mostafa Hosseinpour-Mashkani. "Single-Source Molecular Precursor for Synthesis of Copper Sulfide Nanostructures". Journal of Cluster Science 23, n. 4 (12 settembre 2012): 1143–51. http://dx.doi.org/10.1007/s10876-012-0509-4.

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Salavati-Niasari, Masoud, Azam Sobhani e Fatemeh Davar. "Synthesis of star-shaped PbS nanocrystals using single-source precursor". Journal of Alloys and Compounds 507, n. 1 (settembre 2010): 77–83. http://dx.doi.org/10.1016/j.jallcom.2010.06.062.

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Peng, Long, Shuling Shen, Yejun Zhang, Huarui Xu e Qiangbin Wang. "Controllable synthesis of MnS nanocrystals from a single-source precursor". Journal of Colloid and Interface Science 377, n. 1 (luglio 2012): 13–17. http://dx.doi.org/10.1016/j.jcis.2012.03.052.

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Vasudevan, Aswathy. "Single Step Metal Nanoparticle Fabrication Using Atmospheric Pressure Plasma Jets". ECS Meeting Abstracts MA2022-02, n. 19 (9 ottobre 2022): 898. http://dx.doi.org/10.1149/ma2022-0219898mtgabs.

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The interaction of atmospheric pressure plasma discharges with liquid or vapour phases is a hot-topic in plasma science and technology. Synthesis and processing of nanomaterials using atmospheric pressure plasma jets attracts more attention because of its simplicity and cost effectiveness. The plasma containing reactive electrons and active chemical species activates physical processes and reduction reaction of metal salts which leads to the formation of metal nanoparticles. Among the unique features of atmospheric pressure plasmas, the chemical non-equilibrium environment produces highly reactive radicals and ions from the precursors as well as inside the plasma. Thus the energy transfer could be initiated with high energy electrons and excited species from plasma and could be achieved by the reactions with reactive species of the precursors. Plasma compliments the production of nanomaterials in vapour phase or from aerosols and in solutions of the precursors. The interface between plasmas and vapors can be employed for rapid, simultaneous reduction and deposition of metal nanoparticles from metal salts, for instance gold nanoparticles from chloroauric acid (HAuCl4). We have employed an atmospheric pressure plasma jet setup operating with a mixture of He and Ar gases to produce gold nanocrystals onto a silicon wafer substrate. In this study, it reveals an easy and reliable synthesis mechanism of gold nanoparticles from chloroauric acid using atmospheric pressure plasma jet working with a high voltage source. A solution of the precursor in water acts as the feed solution for the process which is introduced to plasma in the form of microdroplets and metal nanoparticles were formed inside the plasma from the vapours containing the precursor molecules. Since the plasma-liquid/vapour chemistry allows the lead of accelerated reactions and instantly reduce the metal ions to metal atoms skipping the intermediate steps in the reduction process. The nanoparticles were collected on to a Si wafer substrate downstream of the plasma jet and characterized via scanning electron microscopy, Raman spectroscopy, transition electron microscopy etc. The polygonal nanoparticles sized 40-100 nm were obtained and they do not tend to agglomerate or fuse onto the substrate. Due to the low volatility of the precursor solution and the presence of comparatively larger microdroplets inside the plasma the nanoparticles tend to deposit in a pattern like galaxies on the silicon wafer substrate. These results would lead to the development of low cost and mobile, user-friendly atmospheric pressure plasma devices for the synthesis of nanoparticles without any toxic chemicals for the reduction of metal salt. The challenge in this process is in creating a vapour-plasma interface directly. This problem has been solved by incorporating a vaporizer directly to plasma. The vaporizer would introduce a new phase which would be a combination of gaseous plasma and plasma-liquid interface. To ease the transportation and diffusion of precursor molecules at the interface an inert gas has been introduced to the vaporizer as a carrier. At the interface, high energy electrons are introduced to the vapors containing the precursor metal ions and these wet electrons play the key role as initiators for the reduction process inside the plasma. Nanoparticles are formed inside the plasma by simple reduction mechanism carried out by short-lived reducing species formed at the interface. From the qualitative analysis carried our during the process implies the formation of short-lived reducing agents like hydrogen peroxide (H2O2) which is known as a reducing agent for chloroaurate ions in water medium. The size and shape of the nanoparticles are controlled by the residence time of the particles inside the plasma and the population density of the metal ions. Whereas the purity in turn the reduction rate of metal ions are dependent upon the feed gas flow as well as the applied voltage, i.e. plasma power. Concisely, atmospheric pressure plasma jets are outstanding choice for the synthesis of gold nanoparticles from chloroauric acid without any external reducing agents. The synthesized gold nanoparticles are promising for different applications because of its geometry and shape. Because of its polygonal geometries the particles are plasmonic active surfaces, the functional for highly specific sensing applications and nanoelectronics devices. However, the low-temperature plasma-vapour interphases containing droplets, the evaporation may add new complexities such as quantitative analysis of non-equilibrium chemistry to plasma chemistry which is yet to be understood and developed.

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GUTIÉRREZ-GARZA, O. E., L. L. GARZA-TOVAR, E. QUIROGA-GONZÁLEZ, N. A. GARCÍA GÓMEZ, Y. PEÑA-MENDEZ e E. M. SÁNCHEZ CERVANTES. "SOLVOTHERMAL SYNTHESIS OF Sb2S3 NEEDLES AND STUDY OF THE EFFECT OF THEIR INTERGROWTH ON THEIR OPTICAL PROPERTIES". Chalcogenide Letters 17, n. 5 (maggio 2020): 257–62. http://dx.doi.org/10.15251/cl.2020.175.257.

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Antimony trisulfide (Sb2S3) was successfully synthesized by the solvothermal route using either inorganic SbCl3 or organic C8H10K2O15Sb2 antimony precursors, and carbon disulfide as sulfur precursor with ethylene glycol as the solvent. The use of SbCl3 resulted in single needles, while C8H10K2O15Sb2 conducted to needle-bundles. In both cases, the crystal structure is orthorhombic (Stibnite), as a single phase. The introduction of structural defects caused by the intergrowth is evidenced by Raman spectroscopy. The defects originate a variation of the optical bandgap of the material.

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Xu, Yebin, Yanyan He e Liangbin Wang. "Synthesis of Ba2Ti9O20 via ethylenediaminetetraacetic acid precursor". Journal of Materials Research 16, n. 4 (aprile 2001): 1195–99. http://dx.doi.org/10.1557/jmr.2001.0165.

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The modified Pechini method using ethylenediaminetetraacetic acid as a chelating agent to prepare Ba2Ti9O20 is reported. The resin precursors were prepared and heated at 700 to 1200 °C in air, and x-ray diffraction was used to determine the phase transformations as a function of temperature. Single-phase Ba2Ti9O20 was obtained at 1200 °C for 2–6 h, without the need of prolonged heat treatment time. The process was simple and easy to control: low-temperature conditions or a protective atmosphere was not needed. Differential thermal analysis, thermogravimetric analysis, and Raman spectroscopy were used to characterize the precursors and derived oxide powders. Details of the synthesis and characterization of the resultant products were given.

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Mann, Patrick Bergstrom, Iain J. McGregor, Struan Bourke, Mary Burkitt-Gray, Simon Fairclough, Michelle T. Ma, Graeme Hogarth, Maya Thanou, Nicholas Long e Mark Green. "An atom efficient, single-source precursor route to plasmonic CuS nanocrystals". Nanoscale Advances 1, n. 2 (2019): 522–26. http://dx.doi.org/10.1039/c8na00325d.

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Potdar, H. S., S. B. Deshpande, P. D. Godbole e S. K. Date. "Synthesis of microcrystalline BaZrO3 via molecular precursor route". Journal of Materials Research 8, n. 5 (maggio 1993): 948–50. http://dx.doi.org/10.1557/jmr.1993.0948.

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A molecular precursor barium zirconyl oxalate (BZO) was synthesized by exchange reaction between freshly generated water soluble sodium zirconyl oxalate and Ba-nitrate solutions at room temperature. The controlled pyrolysis of BZO in air at 800 °C/6 h resulted in the formation of single-phase cubic microcrystalline barium zirconate powder. These powders exhibit variable-shaped agglomerates with an average size ≍0.2 μm having a surface area ≍2.63 m2/gm.

30

Kowalkińska, Marta, Jakub Karczewski e Anna Zielińska-Jurek. "The Effect of Titanium Oxyfluoride Morphology on Photocatalytic Activity of Fluorine-Doped Titanium(IV) Oxide". Crystals 13, n. 2 (19 febbraio 2023): 356. http://dx.doi.org/10.3390/cryst13020356.

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Titanium oxyfluoride (TiOF2) is a metastable product that can be obtained in a fluorine-rich environment. This material can also be a valuable precursor in the synthesis of titanium(IV) oxide (TiO2). However, the effect of TiOF2 morphology on the physicochemical properties of TiO2 has not been studied so far. In this work, single-phase TiOF2 was prepared by a solvothermal method. The as-synthesized samples exhibited a variety of morphologies, including different shapes and crystallite sizes. These materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS), surface area measurements, thermal gravimetric analysis (TGA) and UV–vis diffuse reflectance spectroscopy (DR/UV–vis). Furthermore, TiOF2 samples were used as precursors in the synthesis of fluorine-doped titanium(IV) oxide and applied in photocatalytic phenol degradation under UV-vis light. The experiments showed that the crystallite size of the precursor, as well as the number of fluoride ions used in the synthesis, were the predominant factors that affected the photocatalytic activity of the final photocatalyst.

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Figueiredo, J. F. D., V. Bouquet, S. Députier, O. Merdrignac-Conanec, I. Peron, E. P. Marinho, A. G. Souza, I. M. G. Santos, M. Guilloux-Viry e I. T. Weber. "Zinc-gallium oxynitride powders: effect of the oxide precursor synthesis route". Cerâmica 59, n. 350 (giugno 2013): 269–76. http://dx.doi.org/10.1590/s0366-69132013000200012.

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Zinc-gallium oxynitride powders (ZnGaON) were synthesized by nitridation of ZnGa2O4 oxide precursor obtained by polymeric precursors (PP) and solid state reaction (SSR) methods and the influence of the synthesis route of ZnGa2O4 on the final compound ZnGaON was investigated. Crystalline single phase ZnGa2O4 was obtained at 1100 ºC / 12 h by SSR and at 600 ºC / 2 h by PP with different grain sizes and specific surface areas according to the synthesis route. After nitridation, ZnGaON oxynitrides with a GaN würtzite-type structure were obtained in both cases, however at lower temperatures for PP samples. The microstructure and the specific surface area were strongly dependent on the oxide synthesis method and on the nitridation temperature (42 m²g-1 and 5 m²g-1 for PP and SSR oxides treated at 700 °C, respectively). The composition analyses showed a strong loss of Zn for the PP samples, favored by the increase of ammonolysis temperature and by the higher specific surface area.

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Sutter, Eli, Juan Carlos Idrobo e Peter Sutter. "Synthesis and optoelectronic properties of ultrathin Ga2O3 nanowires". Journal of Materials Chemistry C 8, n. 33 (2020): 11555–62. http://dx.doi.org/10.1039/d0tc02040k.

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Maleki, Mahdi, Ali Beitollahi e Mohammadreza Shokouhimehr. "Template-free synthesis of porous boron nitride using a single source precursor". RSC Advances 5, n. 58 (2015): 46823–28. http://dx.doi.org/10.1039/c5ra04636j.

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34

Sonher, Ramona Bianca, Richard Attila Varga, Mircea Nasui, Traian Petrisor Jr, Mihai Sebastian Gabor, Marin Senila, Alessandro Rufoloni, Traian Petrisor e Lelia Ciontea. "Single Source Precursor for PAD-LaMnO3 Thin Films". Crystals 10, n. 9 (22 settembre 2020): 851. http://dx.doi.org/10.3390/cryst10090851.

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Abstract (sommario):

A new lanthanum and manganese ethylenediaminetetraacetate (EDTA) coordination polymer (EDTA4− = [(CH2N)2(CH2-COOH)(CH2COO)4]) was synthesized from La(NO3)3 and Mn(NO3)2 reagents, ethylenediaminetetraacetic acid, and water at room temperature. The structure of the new compound formed, [{La2Mn3(EDTA)3(H2O)11}·12H2O]n, was determined by the single crystal X-ray diffraction technique. The synthesis and characterization of the La(III) and Mn(II) coordination complex, characterized by FTIR spectroscopy, thermogravimetry, and differential thermal analysis of the complex, are envisaged. X-ray crystal structure determination indicates that seven- and four-coordinate modes between La(III)/Mn(Π) and H4EDTA exist. [{La2Mn3(EDTA)3(H2O)11}·12H2O]n crystallizes in the monoclinic space group C2 with unit cell parameters of a = 16.1227(17) Å, b = 14.8049(16) Å, c = 14.8736(16) Å, and β = 116.107(2)°. Using this precursor, LaMnO3 (LMO) epitaxial thin films were grown by the polymer-assisted deposition (PAD) method on (100)SrTiO3 (STO) single crystalline substrates at a temperature of 900 °C. The LMO crystallized films exhibit a (001)LMO/(001)STO out-of-plane epitaxial relationship and a smooth surface morphology.

35

Chan, Yee Seng, Hironobu Hayashi, Naoki Aratani e Hiroko Yamada. "Polyazaacenes Generation By Using Precursor Methods". ECS Meeting Abstracts MA2022-01, n. 10 (7 luglio 2022): 794. http://dx.doi.org/10.1149/ma2022-0110794mtgabs.

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Azaacenes are the analogue of acenes, comprising nitrogen atoms in the carbon-based molecular skeleton, have been gaining attention because of their potential application in organic electronics and material science. However, it is normally difficult to synthesize such large aromatic molecules because of the poor solubility and low stability. On the other hand, we have developed precursor methods to overcome these problems. Briefly, bicyclo[2.2.2]octadiene(BCOD)-fused acenes can be converted its corresponding acenes by thermally induced retro-Diels–Alder reaction, while α-diketone-type precursors can be converted simply by photoirradiation.[1] Significantly, these precursor molecules are often more soluble and stable than its converted forms. More crucially, their corresponding acenes can be prepared quantitatively in solutions or in films, if the precursors are sufficiently pure. So far, by using the precursor methods, we have successfully synthesized polyacenes under anaerobic conditions either at ultrahigh vacuum conditions or at the interior of single crystals to avoid undesirable oxidation of the resulting polyacenes.[2–4] Here we report a series of tetraazapolyacene precursors synthesis. Briefly, the BCOD moieties were introduced in the tetraazaacenes as the thermally removable leaving group. The possibility of conversion of the precursors into its corresponding tetraazaacenes was examined by thermogravimetric analysis respectively. In addition, α-diketone-type precursor of tetraazaheptacene was also synthesized. Furthermore, we also report the one-pot synthesis of macrocyclic azacyclacene precursor by reacting bis-α-diketo-tetrahydro-diethanopentacene with benzene-1,2,4,5-tetraamine tetrahydrochloride. Here, the targeted compound was clearly confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The obtaining precursor compounds will be subjected to transformation to investigate its optical and physical properties. References H. Yamada, D. Kuzuhara, M. Suzuki, H. Hayashi, N. Aratani, Bull. Chem. Soc. Jpn. 2020, 93, 1234–1267. J. I. Urgel, S. Mishra, H. Hayashi, J. Wilhelm, C. A. Pignedoli, M. D. Giovannantonio, R. Widmer, M. Yamashita, N. Hieda, P. Ruffieux, H. Yamada, F. Roman, Nat. Commun. 2019, 10, 861. H. Hayashi, N. Hieda, M. Yamauchi, Y. S. Chan, N. Aratani, S. Masuo, H. Yamada, Chem. Eur. J. 2020, 26, 15079–15083. K. Eimre, J. I. Urgel, H. Hayashi, M. D. Giovannantonio, P. Ruffieux, S. Sato, S. Otomo, Y. S. Chan, N. Aratani, D. Passerone, O. Gröning, H. Yamada, R. Fasel, C. A. Pignedoli, Nat. Commun. in press.

36

Yang, Le, Pei Zhang, Yao Feng e Zhaoju Yu. "Single-source-precursor synthesis and characterization of SiAlC(O) ceramics from a hyperbranched polyaluminocarbosilane". High Temperature Materials and Processes 41, n. 1 (1 gennaio 2022): 150–60. http://dx.doi.org/10.1515/htmp-2022-0025.

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Abstract Polyaluminocarbosilane (PACS) as a single-source-precursor of SiAlC(O) ceramic was prepared by reacting a hyperbranched allylhydridopolycarbosilane (AHPCS) and aluminum(iii) acetylacetonate (Al(acac)3), and the PACS was characterized using gel-permeation chromatography, Fourier-transform infrared spectroscopy, and nuclear magnetic-resonance spectroscopy. The polymer-to-ceramic transformation of the obtained PACSs was investigated by Fourier-transform infrared spectroscopy and thermogravimetric analysis. The ceramic yield of the PACS was approximately 15% higher than that of the original AHPCS at 1,200°C. The phase composition and microstructure of the final ceramics were studied by X-ray diffraction, energy-dispersive spectroscopy, and scanning electron microscopy. The introduction of aluminum to the SiC(O) ceramics suppressed the β-SiC crystal growth and improved the density of the ceramics that were annealed at 1,800°C, which is advantageous for high-temperature ceramics. The aluminum content of the SiAlC(O) ceramics can be readily controlled by the Al(acac)3 content in the PACS precursors.

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Hamachi, Leslie S., Haoran Yang, Ilan Jen-La Plante, Natalie Saenz, Kevin Qian, Michael P. Campos, Gregory T. Cleveland et al. "Precursor reaction kinetics control compositional grading and size of CdSe1−xSx nanocrystal heterostructures". Chemical Science 10, n. 26 (2019): 6539–52. http://dx.doi.org/10.1039/c9sc00989b.

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38

Alkahlout, A., N. Al Dahoudi, I. Grobelsek, M. Jilavi e P. W. de Oliveira. "Synthesis and Characterization of Aluminum Doped Zinc Oxide Nanostructures via Hydrothermal Route". Journal of Materials 2014 (25 marzo 2014): 1–8. http://dx.doi.org/10.1155/2014/235638.

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Stable crystalline aluminum doped zinc oxide (AZO) nanopowders were synthesized using hydrothermal treatment processing. Three different aluminum precursors have been used. The Al-precursors were found to affect the morphology of the obtained nanopowders. AZO nanoparticles based on zinc acetate and aluminum nitrate have been prepared with different Al/Zn molar ratios. XRD investigations revealed that all the obtained powders have single phase zincite structure with purity of about 99%. The effect of aluminum doping ratio in AZO nanoparticles (based on Al-nitrate precursor) on structure, phase composition, and particle size has been investigated. The incorporation of Al in ZnO was confirmed by UV-Vis spectroscopy revealing a blue shift due to Burstein-Moss effect.

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Giese, André, Sebastian Schipporeit, Volker Buck e Nicolas Wöhrl. "Synthesis of carbon nanowalls from a single-source metal-organic precursor". Beilstein Journal of Nanotechnology 9 (29 giugno 2018): 1895–905. http://dx.doi.org/10.3762/bjnano.9.181.

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In this work, the deposition of carbon nanowalls (CNWs) by inductively coupled plasma enhanced chemical vapor deposition (ICP-PECVD) is investigated. The CNWs are electrically conducting and show a large specific surface area, which is a key characteristic to make them interesting for sensors, catalytic applications or energy-storage systems. It was recently discovered that CNW films can be deposited by the use of the single-source metal-organic precursor aluminium acetylacetonate. This precursor is relatively unknown in combination with the ICP-PECVD deposition method in literature and, thus, based on our previous publication is further investigated in this work to better understand the influence of the various deposition parameters on the growth. Silicon, stainless steel, nickel and copper are used as substrate materials. The CNWs deposited are characterized by scanning electron microscopy (SEM), Raman spectroscopy and Auger electron spectroscopy (AES). The combination of bias voltage, the temperature of the substrate and the substrate material had a strong influence on the morphology of the graphitic carbon nanowall structures. With regard to these results, a first growth model for the deposition of CNWs by ICP-PECVD and aluminium acetylacetonate is proposed. This model explains the formation of four different morphologies (nanorods as well as thorny, straight and curled CNWs) by taking the surface diffusion into account. The surface diffusion depends on the particle energies and the substrate material and thus explains the influence of these parameters.

40

Chen, Guang-Yi, Wen-Gang Qu, Feng Ye, Wan-Xi Zhang e An-Wu Xu. "Hydrothermal Synthesis of Ferroelectric PbHPO4 Nanowires from a Single-Source Precursor". Journal of Physical Chemistry C 112, n. 43 (8 ottobre 2008): 16818–23. http://dx.doi.org/10.1021/jp805881e.

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Davis, Patrick, e Lorenzo Mangolini. "Single precursor synthesis of copper sulfide nanocrystals using aerosol spray pyrolysis". MRS Communications 3, n. 1 (marzo 2013): 57–60. http://dx.doi.org/10.1557/mrc.2013.10.

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Liu, Sha, Hongwang Zhang e Mark T. Swihart. "Spray pyrolysis synthesis of ZnS nanoparticles from a single-source precursor". Nanotechnology 20, n. 23 (19 maggio 2009): 235603. http://dx.doi.org/10.1088/0957-4484/20/23/235603.

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43

Ramaswamy, Sowmianarayanan, e Allan C. Oehlschlager. "Efficient synthesis of exo- and endo-brevicomin from a single precursor". Canadian Journal of Chemistry 67, n. 5 (1 maggio 1989): 794–96. http://dx.doi.org/10.1139/v89-120.

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Abstract (sommario):

Diastereoselective reduction of 2-propionyl-6-methyl-3,4-dihydropyran and its ring opened derivatives, followed by acidic work-up, gives mixtures rich (>9:1) of either exo- or endo-brevicomin. Keywords: exo- and endo-brevicomin, diastereoselective ketone reduction.

44

Armelao, Lidia, Gregorio Bottaro, Laura Crociani, Roberta Seraglia, Eugenio Tondello e Pierino Zanella. "A versatile single-source precursor for the synthesis of LaCoO3 films". Materials Letters 62, n. 8-9 (marzo 2008): 1179–82. http://dx.doi.org/10.1016/j.matlet.2007.08.007.

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45

Wu, Xinglong, Minhua Cao, Changwen Hu e Xiaoyan He. "Sonochemical Synthesis of Prussian Blue Nanocubes from a Single-Source Precursor". Crystal Growth & Design 6, n. 1 (gennaio 2006): 26–28. http://dx.doi.org/10.1021/cg050371x.

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46

Gu, Ening, Xianzhong Lin, Xiaofeng Tang, Gebhard J. Matt, Andres Osvet, Yi Hou, Sebastian Jäger et al. "Single molecular precursor ink for AgBiS2 thin films: synthesis and characterization". Journal of Materials Chemistry C 6, n. 28 (2018): 7642–51. http://dx.doi.org/10.1039/c8tc01195h.

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Tahmasebi, Mohammad Hossein, e Mark Obrovac. "Quantitative Determination of the Compositional Inhomogeneity in NMC Cathode Materials by Williamson-Hall Analysis". ECS Meeting Abstracts MA2023-02, n. 2 (22 dicembre 2023): 184. http://dx.doi.org/10.1149/ma2023-022184mtgabs.

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Over the past decades, the co-precipitation synthesis technique has been used, particularly for making LiNixMnyCozO2 (NMC) cathode materials for lithium-ion batteries (LIBs), due to better control of particle morphology and higher compositional homogeneity in the final NMC product compared to other methods. However, the co-precipitation method introduces complexity and consumes large amounts of energy and water, which can increase cost. This has led researchers to investigate solid-state NMC synthesis techniques in order to improve sustainability and reduce LIB cost [1-3]. Obtaining homogeneous mixing of transition metals at the atomic scale by solid-state methods remains a challenge. Since compositional homogeneity has a vital effect on the electrochemical performance of the NMCs, it is essential to quantitatively estimate the degree of inhomogeneity in cathode materials for the development of new synthesis methods. In the present study, a quantitative X-ray diffraction (XRD) analysis technique using the Williamson-Hall (WH) method is used to determine the degree of inhomogeneity in NMC precursors and NMC cathode materials. In this regard, single-phase rock salt (RS) precursors with varying degrees of transition metal homogeneity were prepared by combining NiO, MnO and CoO by grinding for different times, followed by heating under an Ar flow. Then, NMC cathode materials were made by heating the RS-precursors with lithium carbonate in air. EDS elemental maps showed that transition metal inhomogeneity existed in the RS-precursors and final NMCs and that this inhomogeneity is primarily associated with the Mn distribution (Figure 1(a)). Furthermore, the compositional inhomogeneity became reduced with increasing precursor grinding time. Using a WH analysis method, composition variation in the NMC precursor and in the final NMC product could be quantitatively determined from conventional XRD powder patterns. Utilizing this analysis, it was found that inhomogeneity in the precursor is translated into the final NMC, so that a similar trend in the degree of inhomogeneity was observed for both synthesized precursors and their NMC products (Figure 1(b) and (c)). Additionally, NMCs with high compositional homogeneity showed much better electrochemical performance compared to the samples with higher degree of inhomogeneity. We believe the proposed method is highly useful in the development of new cathode precursors and in predicting the performance of the NMC cathode materials by quantitatively determining their degree of compositional inhomogeneity. References 1. M. N. Obrovac, L. Zheng, and M. D. L. Garayt, Engineered Particle Synthesis by Dry Particle Microgranulation, Cell Reports Physical Science, 1, 100063 (2020). 2. L. Zheng, J. C. Bennett, and M. N. Obrovac, All-Dry Synthesis of Single Crystal NMC Cathode Materials for Li-Ion Batteries, J. Electrochem. Soc., 167, 130536 (2020). 3. M. H. Tahmasebi, L. Zheng, T. D. Hatchard, M. N. Obrovac, Li[Ni0.6Mn0.2Co0.2]O2 Made From Crystalline Rock Salt Oxide Precursors, J. Electrochem. Soc., 170, 030531 (2023). Figure 1

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Michalik-Zym, Alicja, Małgorzata Zimowska, Krzysztof Bahranowski e Ewa Serwicka. "Layered Sodium Disilicates as Precursors of Mesoporous Silicas. Part I: Optimisation of the Synthesis Procedure of δ-Na2Si2O5 and α-Na2Si2O5". Mineralogia 38, n. 2 (1 gennaio 2007): 151–60. http://dx.doi.org/10.2478/v10002-007-0023-8.

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Abstract (sommario):

Layered Sodium Disilicates as Precursors of Mesoporous Silicas. Part I: Optimisation of the Synthesis Procedure of δ-Na2Si2O5 and α-Na2Si2O5Optimization of the synthetic procedures described in literature aimed at preparing pure δ-Na2Si2O5 has been carried out. The results show that a substantial shortening of the calcination time of amorphous silicate precursor is required, in order to minimize the appearance of the thermodynamically stable α-Na2Si2O5. The use of commercial water glass solution rather than freshly synthesized silica/NaOH slurry is the preferred source of the starting amorphous silicate. Optimized preparative routes for synthesis of single-phase δ-Na2Si2O5 and α-Na2Si2O5 have been described.

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Lin, Jie, Wei Zhao, Meng Qian, Kun Liu, Jijian Xu e Fuqiang Huang. "Self-templated synthesis of heavily nitrogen-doped hollow carbon spheres". Chemical Communications 54, n. 36 (2018): 4565–68. http://dx.doi.org/10.1039/c8cc00415c.

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Fox, Jesse M., Rebekah L. Rashford e Lasse Lindahl. "Co-Assembly of 40S and 60S Ribosomal Proteins in Early Steps of Eukaryotic Ribosome Assembly". International Journal of Molecular Sciences 20, n. 11 (8 giugno 2019): 2806. http://dx.doi.org/10.3390/ijms20112806.

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In eukaryotes three of the four ribosomal RNA (rRNA) molecules are transcribed as a long precursor that is processed into mature rRNAs concurrently with the assembly of ribosomal subunits. However, the relative timing of association of ribosomal proteins with the ribosomal precursor particles and the cleavage of the precursor rRNA into the subunit-specific moieties is not known. To address this question, we searched for ribosomal precursors containing components from both subunits. Particles containing specific ribosomal proteins were targeted by inducing synthesis of epitope-tagged ribosomal proteins followed by pull-down with antibodies targeting the tagged protein. By identifying other ribosomal proteins and internal rRNA transcribed spacers (ITS1 and ITS2) in the immuno-purified ribosomal particles, we showed that eS7/S7 and uL4/L4 bind to nascent ribosomes prior to the separation of 40S and 60S specific segments, while uS4/S9, uL22, and eL13/L13 are bound after, or simultaneously with, the separation. Thus, the incorporation of ribosomal proteins from the two subunits begins as a co-assembly with a single rRNA molecule, but is finished as an assembly onto separate precursors for the two subunits.