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81.
Li Weinan 《中国科学A辑(英文版)》1998,41(1):55-63
The determination of the electron-phonon interaction function (EPIF) from the temperature dependence of the electrical resistivity
(TDER) for metals within a selected moderate temperature range is numerically demonstrated based on the general theory of
the amplitude-phase-retrieval problem and an iterative algorithm. From the model calculation, the convergent solution can
be obtained; however, the profile of the recovered EPIF depends on the initial frequency distribution used in the algorithm
since this inversion problem is inherently ill-posed. In order to get reasonable result, it is necessary to introduce additional
information about the feature of the EPIF for guiding the choice of the initial distribution. The algorithm can also furnish
a robust reconstruction of EPIF from TDER contaminated with random noise. It means that this algorithm is relatively stable
and insensitive to external perturbation; therefore in a sense, the presented algorithm overcomes the ill-posedness of the
inversion problem. 相似文献
82.
为提高四轴飞行器的数据采集与数据处理能力,降低四轴飞行器的功耗,研制了一种基于FPGA的四轴飞行控制器。飞行控制器以NIOS II处理器为控制核心,结合嵌入的SPI、I2C、UART等IP核实现了数据的实时采集与快速处理,并提出并行处理PPM解码和编码、超声波检测与控制、蜂鸣器控制的设计方案,利用VerilogHDL语言在FPGA上设计了这些并行处理功能模块,这些功能模块通过PIO核与NIOS II处理器连接,能够自主完成所规定的处理功能。经过多次飞行测试,四轴飞行器能够稳定的起飞和降落,快速的飞行,转弯,上升和下降,也能够避开障碍物,验证了四轴飞行控制器功能稳定,功耗较低,已达到设计的要求。 相似文献
83.
Si Liu Weinan Chen Chuan Yan Fan Zhou Zhanglang Zhou Min Wang Prof. Dr. Gang Zhou 《European journal of organic chemistry》2023,26(26):e202300331
Incorporation of tellurium into polycyclic compounds may endow them with unique chemical and optoelectronic properties which are not observed in their lighter chalcogen analogues. Herein, a telluropyran-containing polycyclic compound ( T1 ) synthesized through a ring-expansion reaction from the corresponding tellurophene analogue can be reversibly oxidized into halogen adducts T1•X2 (X=Cl, Br, I) with the formation of two Te−X bonds. Their chemical structures have been verified by two-dimensional 1H-1H correlation spectroscopy and single crystal X-ray diffraction analysis. The halogen oxidations of T1 and the reverse thermal eliminations as well as the halogen exchange in halogen adducts T1•X2 have been systematically investigated and compared by UV-vis absorption titration, electrochemical measurements, thermogravimetric analysis, and density functional calculations (DFT). The oxidation of Te(II) in T1 to Te(IV) in T1•X2 results in the switch from aromaticity to nonaromaticity for the six-membered telluropyran ring, as revealed by nucleus-independent chemical shift calculations. It is also found that the halides in the halogen adducts can be exchanged by lighter ones, but not vice versa. The stabilities of the oxidized products are in the order of T1•Cl2 > T1•Br2 > T1•I2 , which are consistent with the calculated rate constants and energy barriers of the elimination reactions. 相似文献
84.
Qi Zhong Weinan Wang Joseph Adelsberger Anastasia Golosova Achille M. Bivigou Koumba Andre Laschewsky Sergio S. Funari Jan Perlich Stephan V. Roth Christine M. Papadakis Peter M��ller-Buschbaum 《Colloid and polymer science》2011,289(5-6):569-581
The thermal behavior of poly(methoxydiethylenglycol acrylate) (PMDEGA) is studied in thin hydrogel films on solid supports and is compared with the behavior in aqueous solution. The PMDEGA hydrogel film thickness is varied from 2 to 422?nm. Initially, these films are homogenous, as measured with optical microscopy, atomic force microscopy, X-ray reflectivity, and grazing-incidence small-angle X-ray scattering (GISAXS). However, they tend to de-wet when stored under ambient conditions. Along the surface normal, no long-ranged correlations between substrate and film surface are detected with GISAXS, due to the high mobility of the polymer at room temperature. The swelling of the hydrogel films as a function of the water vapor pressure and the temperature are probed for saturated water vapor pressures between 2,380 and 3,170?Pa. While the swelling capability is found to increase with water vapor pressure, swelling in dependence on the temperature revealed a collapse phase transition of a lower critical solution temperature type. The transition temperature decreases from 40.6?°C to 36.6?°C with increasing film thickness, but is independent of the thickness for very thin films below a thickness of 40?nm. The observed transition temperature range compares well with the cloud points observed in dilute (0.1?wt.%) and semi-dilute (5?wt.%) solution which decrease from 45?°C to 39?°C with increasing concentration. 相似文献
85.
86.
Advance and Designing Strategies in Polymeric Antifungal Agents Inspired by Membrane-Active Peptides
Weinan Jiang Yueming Wu Min Zhou Prof. Gonghua Song Prof. Runhui Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(65):e202202226
The high-mortality invasive fungal infections seriously threaten the lives of immunocompromised people. Host defense peptides and cell-penetrating peptides are representative membrane-active peptides with different functions. Among them, host defense peptides mimicking is a valid strategy in the design of synthetic antifungal agents. Despite the brilliance in the field of intracellular delivery, the potential of cell-penetrating peptides and their mimics for designing antifungal agents has been overlooked. In this concept article, we describe the structural design of synthetic antifungal polymers as mimics of host defense peptides, and highlight the effectiveness and potential of cell-penetrating peptide-inspired strategy in designing potent and selective antifungal polymeric agents. In addition, an outlook for further expanding the design horizons of antifungal polymers is also presented. 相似文献
87.
We study the propagation of initial osillations in the solutions of one-dimensional inviscid gas dynamic equations and the compressible Navier-Stokes equations. Using Multiple scale analysis, we derivbe the homogenized equations which take the form of n averaged system coupled with a dynamic cell-problem. We prove rigorous error estimates to justify the validity of these equations. We also show that the weak limits of the osicllatory solytions satisfy gas dynamic equations with an equation of state depeding on the microstructurer of the inital data 相似文献
88.
89.
Analysis of the heterogeneous multiscale method for elliptic homogenization problems 总被引:1,自引:0,他引:1
Weinan E Pingbing Ming Pingwen Zhang 《Journal of the American Mathematical Society》2005,18(1):121-156
A comprehensive analysis is presented for the heterogeneous multiscale method (HMM for short) applied to various elliptic homogenization problems. These problems can be either linear or nonlinear, with deterministic or random coefficients. In most cases considered, optimal estimates are proved for the error between the HMM solutions and the homogenized solutions. Strategies for retrieving the microstructural information from the HMM solutions are discussed and analyzed.
90.
正This special issue of SCIENCE CHINA Mathematics commemorates the 8th International Congress on Industrial and Applied Mathematics(ICIAM)held at China National Convention Center,Beijing,China from August 10 to 14,2015.More than 3100 applied mathematicians from over 70 countries and regions 相似文献