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991.
Xianxiu Qiu Pengfei Qiu Tingting Deng Hui Huang Xiaolong Du Xun Shi Lidong Chen 《无机化学与普通化学杂志》2020,646(14):1116-1121
Cu-Fe-S-based compounds gain the interest from thermoelectric community because all the consisting elements, Cu, Fe, and S, are non-toxic and earth-abundant. Comparing with CuFeS2 and Cu5FeS4, the investigation on Cu9Fe9S16 is very rare. In this work, a series of Cu9–xFe9+xS16 samples were fabricated by means of melting-annealing process. Their phase composition, microstructure, electrical and thermal transport properties were systematically investigated. X-ray measurement confirms that all samples are phase pure. Transmission electron microscopy characterization indicates that the fabricated Cu9Fe9S16 has a natural nanostructure. Cu9Fe9S16 shows semiconducting-like electrical transport behavior and intrinsically low lattice thermal conductivity. Beyond the numerous boundaries between nanosized grains, the existence of low-frequency optical phonons is also responsible for the intrinsically low lattice thermal conductivity. Doping Fe at the Cu-sites in Cu9Fe9S16 significantly alters the electrical transport properties by introducing extra carriers. A peak dimensionless figure of merit zT value of 0.21 is obtained at 800 K for pure Cu9Fe9S16, which is comparable with that for CuFeS2. 相似文献
992.
Michael Woolman Jimmy Qiu Claudia M. Kuzan-Fischer Isabelle Ferry Delaram Dara Lauren Katz Fowad Daud Megan Wu Manuela Ventura Nicholas Bernards Harley Chan Inga Fricke Mark Zaidi Brad G. Wouters James T. Rutka Sunit Das Jonathan Irish Robert Weersink Howard J. Ginsberg David A. Jaffray Arash Zarrine-Afsar 《Chemical science》2020,11(33):8723
Integration between a hand-held mass spectrometry desorption probe based on picosecond infrared laser technology (PIRL-MS) and an optical surgical tracking system demonstrates in situ tissue pathology from point-sampled mass spectrometry data. Spatially encoded pathology classifications are displayed at the site of laser sampling as color-coded pixels in an augmented reality video feed of the surgical field of view. This is enabled by two-way communication between surgical navigation and mass spectrometry data analysis platforms through a custom-built interface. Performance of the system was evaluated using murine models of human cancers sampled in situ in the presence of body fluids with a technical pixel error of 1.0 ± 0.2 mm, suggesting a 84% or 92% (excluding one outlier) cancer type classification rate across different molecular models that distinguish cell-lines of each class of breast, brain, head and neck murine models. Further, through end-point immunohistochemical staining for DNA damage, cell death and neuronal viability, spatially encoded PIRL-MS sampling is shown to produce classifiable mass spectral data from living murine brain tissue, with levels of neuronal damage that are comparable to those induced by a surgical scalpel. This highlights the potential of spatially encoded PIRL-MS analysis for in vivo use during neurosurgical applications of cancer type determination or point-sampling in vivo tissue during tumor bed examination to assess cancer removal. The interface developed herein for the analysis and the display of spatially encoded PIRL-MS data can be adapted to other hand-held mass spectrometry analysis probes currently available.Integration between a hand-held mass spectrometry desorption probe based on picosecond infrared laser technology (PIRL-MS) and an optical surgical tracking system demonstrates in situ tissue pathology from point-sampled mass spectrometry data. 相似文献
993.
Fen Luo Liduo Wang Beibei Ma Yong Qiu 《Journal of photochemistry and photobiology. A, Chemistry》2008,197(2-3):375-381
In this study, dye-sensitized TiO2 electrodes were immersed into a solution of aluminum isopropoxide and after hydrolysis quasi-solid-state solar cells were fabricated. The interaction between the dye and the resulting Al2O3 overlayer was investigated by ultraviolet–visible (UV–vis) spectrum, Fourier transform infrared (FTIR) spectrum and X-ray photoelectron spectrum (XPS). The current density–voltage (I–V) characteristics showed that the overlayer increased the photovoltage and decreased the photocurrent under low intensity irradiation, and increased both the photovoltage and photocurrent under AM 1.5 irradiation. The Al2O3 overlayer at the dye/electrolyte interface resulted in a 28% improvement in overall photo-to-electrical conversion efficiency from 2.60 to 3.32%. Dark current measurements showed that Al2O3 acted as an insulator barrier to retard recombination between the TiO2 and dye/quasi-solid-state electrolyte interface. Without encapsulation, dye-sensitized solar cells with Al2O3 coating after sensitization also exhibited improved stability compared to cells without coating. 相似文献
994.
Jijun Qiu Weidong Yu Xiangdong Gao Xiaomin Li Weizhen He Se-Jeong Park Hyung-Kook Kim Yong-Hwae Hwang 《Journal of Sol-Gel Science and Technology》2008,47(2):187-193
Silver nanoparticles well dispersed in a spherical Poly(vinylpyrollidone)(PVP) matrix were simply prepared by spray pyrolysis
of aqueous solutions of AgNO3 and PVP without any reducing agent. Highly monodisperse silver particles were obtained above the initial mass ratio of PVP/AgNO3 ∼ 1 and in a certain narrow temperature range. Below the critical mass ratio the silver particles grew to larger ones polydispersely.
As the ratio increased above it, they became smaller maintaining their monodispersity. The use of PVP considerably decreased
the reduction temperature of the silver nitrate from 450 °C to 250 °C under the same pyrolysis conditions, due to its reducing
nature. As the pyrolysis temperature increased above the decomposition temperature of PVP, the silver particles in the matrix
grew to merge to a single particle while their crystallite size did not increase as much. The spherical assemblies of the
silver nanoparticles were hardly disengaged even after severe washing off the matrix materials. The mechanism of the nanoparticle
growth was also discussed. 相似文献
995.
996.
Xiao Jie He Qun Qiu Shengchao Li Haoquan Wang Binghua Zhang Bin Bu Weifeng 《中国科学:化学(英文版)》2020,63(6):792-801
It is well-known that amphiphilic star-shaped copolymers can self-assemble in selective solvents to form complicated micellar constructs as a synergistic result of both the topological constraints and relative volume fractions of the arms. Although the association phenomena of amphiphilic stars have been observed in nonselective solvents, both the structural detail and formation mechanism of these associates are not clear yet. Moreover, these experimental observations are controversial with respect to molecularly dispersed starlike copolymers in nonselective solvents as is popularly believed. To clarify these issues, we have synthesized a series of polyoxometalate-based polystyrene-poly(ethylene glycol)(PS-PEG) miktoarm star supramolecular copolymers(SEW-1–5) by coupling a Keggin-type polyoxometalate of K_4[α-SiW_(12)O_(40)] with 1,2,3-triazolium bridged block copolymers of-PS_n-b~+-PEG_mI~-(n=17, 26, 39, 57, 81; m=45) through ionic exchange reactions, respectively. TEM imaging,contact angle and ~1H NMR studies reveal that SEW-2–5 self-assemble in chloroform, THF, and toluene to create micellelike aggregates ranging from cylinder to sphere with a PS corona and a PEG core, while for SEW-1, reverse bilayers are captured with a PEG corona and a PS core. Among these aggregates, the Keggin clusters of [α-SiW_(12)O_(40)]~(4-) localize at the core-corona interfaces between PS and PEG. In terms of solvent quality, chloroform, THF, and toluene are only slightly poorer for PEG than that for PS with a relative order of chloroformTHFtoluene. These unexpected aggregates originate from the topological constraints of the chemically different arms of PS and PEG in the miktoarm stars, where the weak incompatibility between the PS and PEG arms is intensified appropriately. The presence of the reverse bilayered structures of SEW-1 is due to the magnified steric hindrance of the PEG45 arm with decreasing the molecular weight of the PS17 arm. However, to the best of our knowledge,these are the first examples clearly indicating that miktoarm star copolymers can self-assemble in common good solvents or slightly selective solvents to generate micellelike aggregates. This scenario is not only in sharp contrast to the intuitively considered behavior of unimolecular miktoarm stars in nonselective solvents, but also rather different from the conventional selfassembly behavior of amphiphilic star copolymers in selective solvents. 相似文献
997.
Yuan Jun Zhang Chujun Chen Honggang Zhu Can Cheung Sin Hang Qiu Beibei Cai Fangfang Wei Qingya Liu Wei Yin Hang Zhang Rui Zhang Jidong Liu Ye Zhang Huotian Liu Weifang Peng Hongjian Yang Junliang Meng Lei Gao Feng So Shukong Li Yongfang Zou Yingping 《中国科学:化学(英文版)》2020,63(8):1159-1168
Recent advances in material design for organic solar cells(OSCs) are primarily focused on developing near-infrared nonfullerene acceptors, typically A-DA′D-A type acceptors(where A abbreviates an electron-withdrawing moiety and D, an electron-donor moiety), to achieve high external quantum efficiency while maintaining low voltage loss. However, the charge transport is still constrained by unfavorable molecular conformations, resulting in high energetic disorder and limiting the device performance. Here, a facile design strategy is reported by introducing the "wing"(alkyl chains) at the terminal of the DA′D central core of the A-DA′D-A type acceptor to achieve a favorable and ordered molecular orientation and therefore facilitate charge carrier transport. Benefitting from the reduced disorder, the electron mobilities could be significantly enhanced for the"wing"-containing molecules. By carefully changing the length of alkyl chains, the mobility of acceptor has been tuned to match with that of donor, leading to a minimized charge imbalance factor and a high fill factor(FF). We further provide useful design strategies for highly efficient OSCs with high FF. 相似文献
998.
The synchronization of diagnosis and treatment is a new trend in cancer treatment. Photoacoustic imaging (PAI) and photothermal therapy (PTT) are recognized as one of the perfect combinations. The autocatalytic polymerization of selenium/polypyrrole (Se@PPy) nanocomposites with a wide-absorption band at near-infrared region (NIR, 800 nm) has been developed in this paper. The wide optical absorption characteristics enable Se@PPy nanocomposites to achieve multi-spectral PAI. Ex vivo experiments show desirable photoacoustic ability of the Se@PPy nanocomposites at wavelengths ranging from 700 nm to 900 nm, which is better than that of commercial indocyanine green (ICG). Se@PPy nanocomposites have high photothermal conversion efficiency up to 36.3% as well as excellent photo-thermal stability. In vitro cytotoxicity test demonstrates that the Se@PPy nanocomposites have good bio-safety. Furthermore, the feasibility of Se@PPy nanocomposites for enhancing multi-spectral PAI guided PTT was verified on 4T1 tumor-bearing nude mice. Our results indicate that Se@PPy nanocomposites could be used as an effective theranostic agent for near-infrared light-mediated PAI and PTT of tumor. 相似文献
999.
1000.
磷酸锂原位包覆富锂锰基锂离子电池正极材料 总被引:1,自引:0,他引:1
本工作通过“碳酸盐共沉淀-沉淀转化-固相反应”方法,实现磷酸锂原位包覆和改性富锂锰基锂离子电池正极材料Li1.2Mn0.54Co0.13Ni0.13O2,研究了磷酸锂包覆层的形成过程及其对电化学性能的影响.结果显示,碳酸盐前驱体经沉淀转化反应原位形成磷酸镍包覆层,与锂源混合煅烧,最终转化为厚度小于30 nm的磷酸锂包覆层.该材料组装的半电池在125 mAh·g-1电流密度下循环175圈后容量达191.1 mAh·g-1,容量保持率为81.8%,平均每圈电压衰减仅为1.09 mV.磷酸锂包覆层缓解了材料表面与电解液之间的副反应,抑制了不可逆相变和过渡金属溶出,同时磷酸锂作为锂离子导体促进锂离子传输.本工作表明沉淀转化法原位包覆磷酸锂是提升富锂锰基正极材料性能的有效途径. 相似文献