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151.
刘星元  王淑梅 《发光学报》1999,20(2):180-183
聚合物作为一种有机发光材料,由于在平板显示和光电子器件中的良好应用前景而受到广泛研究[1~2].近年来,一个重要进展是在聚合物中观测到了受激发射(简称Poly-mer激光)现象[3~6].Polymer激光最早是在溶液中实现的[3~4].作为一种新型...  相似文献   
152.
Nano-hydroxyapatite (HA)/poly(l-lactide) (PLLA) composite microspheres with relatively uniform size distribution were prepared by a solid-in-oil-in-water (s/o/w) emusion solvent evaporation method. The encapsulation of the HA nanopaticles in microshperes was significantly improved by grafting PLLA on the surface of the HA nanoparticles (p-HA) during emulsion process. This procedure gave a possibility to obtain p-HA/PLLA composite microspheres with uniform morphology and the encapsulated p-HA nanoparticle loading reached up to 40 wt% (33 wt% of pure HA) in the p-HA/PLLA composite microspheres. The microstructure of composite microspheres from core-shell to single phase changed with the variation of p-HA to PLLA ratios. p-HA/PLLA composite microspheres with the diameter range of 2–3 μm were obtained. The entrapment efficiency of p-HA in microspheres could high up to 90 wt% and that of HA was only 13 wt%. Surface and bulk characterizations of the composite microspheres were performed by measurements such as wide angle X-ray diffraction (WAXD), thermal gravimetric analysis (TGA), environmental scanning electron microscope (ESEM) and transmission electron microscopy (TEM).  相似文献   
153.
Quality control methods of current traditional Chinese medicine (TCM) preparation is time-consuming and difficult to assess in terms of overall efficiency of the drug. A non-destructive rapid near-infrared spectroscopy detection system for key chemical components and biological activity of Lanqin oral solution (LOS), one of the best-selling TCM formulations, was established for comprehensive quality evaluation. Near infrared spectral scanning was carried out on 101 batches of commercial LOS under the penetrated vial state and traditional state. RAW 264.7 cells were cultured to detect the anti-inflammatory ability of LOS, and the reference concentrations of epigoitrin, geniposide, and baicalin were obtained by HPLC. The quantitative models were optimized by three kinds of variable selection methods. The correlation coefficients of prediction value of the models were greater than 0.94. The system also passed the external validation. The performance of the non-invasive models was similar to the traditional models. The established non-destructive system can be applied to the rapid quality inspection of LOS to avoid unqualified drugs from entering the market and ensure drug effectiveness. The biological activity index of LOS was introduced and predicted by NIRs for the first time, which provides a new idea about the quality control of TCM formulations.  相似文献   
154.
曹正汉  钟珮  聂晶 《高分子学报》2021,53(9):95-112
郡县制国家的传统职能是“管人”,但是在当代,为了适应现代世界,需要加强和完善“管事”的职能。然而,加强“管事”的职能遇到的一大障碍,是“管事”与“管人”通常难以分开,带来管事与管人的冲突。在全国性公共事务上,面对管事与管人的冲突,郡县制国家的一种改革方向,即建立中央统一管理与地方属地管理相结合的体制,既扩大中央政府的治理职能,同时又发挥纵向约束机制的作用,从而能改善全国性公共事务治理。此种中央统一管理与地方属地管理相结合的体制,通常不是中央政府事先设计出来的,而是在改革过程中,经由中央政府与地方政府的策略性互动过程,逐渐建立起来的。因此,郡县制国家蕴含着一种潜力,即在公共事务治理上,包括地方公共事务和全国性公共事务,可以引入和发挥“纵向约束机制”的作用,使得国家既保持“管人”的基本体制不变,又能提高治理能力。  相似文献   
155.
刘静 《高分子学报》2021,53(9):28-37
生物技术革命所带来的基因编辑技术,使人类充当“上帝”的角色,成为自身的造物主,具有“设计生命”和“人的再造”的能力,但这一技术革命却带来了对人类尊严的存在论根基的严重挑战,引发了最深刻的伦理学新问题。当代自由主义优生学者提出,人类能够以“玩弄上帝”的方式去改变和重新创造人类自身,而这一再创造的存在论后果却是一个悖谬:人类在获得极度自由的同时,却摧毁了人之为人的尊严的根基,从而彻底失去生命存在的自由本性。按照康德的教诲,尊严是人之为人的最高伦理价值,尊严并不仅仅是出于个体自主性的“权利”和“自尊”,而是出于普遍道德自主性之上的“责任”和“敬重”,人的自由本性的道德自律才是人的尊严和崇高所在。后形而上学思想家进一步发展了康德的尊严观点,在他者和公共性维度上提出一种建立在承认、交互性和交往共同体基础之上的新尊严理论。面对生物技术的滥用和人类尊严受到的挑战,伦理学需要保卫和重建尊严概念,在“自由者的共在关系”中寻求尊严的基础和规范性的力量,从开放的“我们”推演出对“未来人”的责任。  相似文献   
156.
Giant vesicles have been of intense interest as the model system for cell membranes. To bring numerous applications of the vesicles into full play, the existence time of the vesicles becomes particularly important. In this work, we explored the existence time of the vesicles in distilled water under four kinds of representative alternative current (AC) electric fields with different energizing time. When the application time of AC electric field reached 1 hour, the existence time of the vesicles reached the maximum value. As the applied electric field time increased, the existence time of the vesicles decreased. Thus, after obtaining the best vesicles on the carbon fiber electrode, disconnecting the external electric field is very necessary. Based on the in situ observation using inverted microscope, the disappearing phenomena of the vesicles were presented. In addition, it is found that vesicles in phosphate buffer solutions (PBSs) can last about 2–3 days when the electric field was applied for 1 hour, which was much longer than that in distilled water.  相似文献   
157.
An organic solvent-tolerant lipase from Serratia marcescens ECU1010 (rSML) was overproduced in Escherichia coli in an insoluble form. High concentrations of both biomass (50 g cell wet weight/L culture broth) and inclusion bodies (10.5 g/L) were obtained by applying a high-cell-density cultivation procedure. Activity assays indicated that the enzymatic activity of rSML reached 600 U/L. After treatment with isopropyl ether for 12 h, the maximum lipase activity reached 6,000 U/L. Scanning electron microscopy and Fourier transform infrared microspectroscopy revealed the activation mechanism of rSML in the presence of organic solvents. rSML was stable in broad ranges of temperatures and pH values, as well as in a series of organic solvents. Besides, rSML showed the best enantioselectivity for the kinetic resolution of (±)-trans-3-(4-methoxyphenyl)glycidic acid methyl ester. These features render the S. marcescens ECU1010 lipase attractive for biotechnological applications in the field of organic synthesis and pharmaceutical industry.  相似文献   
158.
Molecular Dynamics (MD) is employed to investigate nonthermal melting triggered by coherent phonon excitation in bismuth telluride, which has Peierls distortion in the lattice structure. Results showed that the structural distortion caused by coherent phonons appears as early as 80 fs, while it takes several picoseconds for the whole phonon-excited area to evolve into a liquid state. It was also found that the temperature in the phonon-excited area rises quickly within tens of femtoseconds, while the rest of the lattice remains at the initial temperature even after several picoseconds, which is separated from the high temperature region across a thin transition area. This phenomenon is analogous to the heat transfer across a solid–liquid interface, even though in our case there is no abrupt solid-liquid interface between the cold lattice and the quasiliquid.  相似文献   
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