Semi cover-avoiding properties of finite groups

In this paper, we characterize the nilpotency and supersolvability of a finite group G by assuming some subgroups of prime power order have the semi cover-avoiding property in G. Some earlier results are generalized.     

甲基单胞菌GYJ3催化环氧丙烷的半连续合成

利用含有甲烷单加氢酶（MMO）的甲烷氧化细菌整催化丙烷环氧化制取环氧丙烷,其产物抑制和辅酶NADH消耗是反应难以连续进行的主要原因,采用甲烷再生NADH,研究了丙烯和甲烷共氧化和氧物氧丙烷积累对甲基单胞菌GYJ3的环氧化活性的影响,并考察了在具有产物连续收系统的两段式生物反应器中用细菌胞悬浮液半连续生产环氧丙烷的可行性,将再生和环氧化过程分开进行,以减小甲烷和丙烯的竞争抑制,通过连续抽提产物环氧丙烷,克服了产物抑制,该半连续过程分别在不同的温度下共进行了70h,产生环氧丙烷438μmol。     

聚合物半导体电致发光显示器件

列举了聚合物半导体发光显示器件(PLED)近年来取得的主要突破性成果.简要介绍了PLED的工作原理,阐述了影响PLED量子效率的因素.以最近常用的多层PLED为重点,介绍了载流子传输聚合物的设计、合成及其在PLED中的作用.最后,对PLED的主要用途、目前存在的问题及今后的发展前景进行了评述.     

von Willebrand Factor multimers profiling with a semi‐automated system

Abnormalities in plasma von Willebrand factor (vWF) concentration and function result in von Willebrand disease (vWD). The diagnosis requires a battery of tests such as screening procedures, confirmatory tests, phenotypic characterization, and genotyping. The phenotypic testing (multimer pattern analysis) is important in order to subclassify the hereditary and the acquired forms of vWD. Only few laboratories are skilled to perform this analysis. The extreme range of protein size from 250 kDa monomer to over 20 000 kDa multimers requires a time‐consuming procedure (3–4 days) and presents many technical difficulties. To standardize the method and to overcome technical difficulties, we developed a rapid and sensitive semi‐automated method to visualize the multimeric structure of vWF. The semi‐automated method we present performs the electrophoresis of patient's plasma in 120 min on a precast gel. Gels are suitable for the G26 Interlab instrumentation. After gel blotting, the method allows visualization of the vWF multimer pattern directly on the membrane. We reduced the time required from 72 to 8 h and we propose this test for the first level screening of vWF multimer deficiency.     

Gas-diffusion microextraction

Gas-diffusion microextraction (GDME) is an innovative technique that combines the advantages of membrane-aided gas-diffusion with microextraction concepts. GDME makes uses of a novel portable and low-cost device that comprises a small, commercially available, semi-permeable membrane. Furthermore, if derivatization is integrated into the GDME concept, considerable enrichment factors can be obtained. It may become a powerful tool for any analyst who intends to quantify volatile and semi-volatile analytes in various kinds of matrices. The analysis of vicinal diketones in beer was used as a case study to show GDME applicability and capabilities. Vicinal diketones were derivatized with o-phenylenediamine and then determined by HPLC-UV. Obtained results showed good repeatability and precision with extraction periods at the minute time span.     

区间值模糊命题逻辑系统的广义恒真式

建立区间值模糊命题逻辑系统F(∨，∧，σ┴，c)，其中，α^-θ┴b=(α^-)^c┴b^-,┴是I[0,1]中的t-余范；讨论系统F(∨，∧，σ┴，c)与对应的模糊命题逻辑系统F(∨，∧，σ┴，c)在广义恒真式方面的相互关系，得到定理：T^-[0,α]（F^-∨，∧，σ┴，c)=Tα(F(∨，∧，σ┴，c))。     

Blue emission from arsenic doped gallium nitride

We have observed strong blue emission at room temperature from arsenic doped GaN samples grown by molecular beam epitaxy. Similar results were obtained for samples doped with both arsenic dimers and tetramers. The origin of this blue emission is discussed and a growth model proposed to account for our observations. We propose that arsenic doped GaN may be a suitable replacement for (InGa)N as the active region for blue light emitting devices.     

已知工件最大加工时间的两台同类机半在线问题

考虑已知工件最大加工时间的两台同类机半在线问题．机器M1,M2的速度分别为s1=1,s2=s(s≥1),工件是一个一个独立地到来,工件的信息是逐个释放的,但所有工件中加工时间为最大的工件的加工时间是已知的,目标函数为极小化最大机器负载．此模型简记为Q2／known largest job／Cmax．作者给出了Qmax2算法并证明此算法的竞争比为2(s 1)/s 2(1≤s≤2)和(s 1)/s(s>2),且是紧的．同时给出Q2／known largest job／Cmax问题的一个下界,并且证明Qmax2算法的竞争比与最优算法竞争比之差不大于1/4.     

Molecular dynamics investigation of water adsorption on rutile surfaces

Born-Oppenheimer molecular dynamics (MD) simulations were performed in the framework of the semi-empirical molecular orbital method MSINDO to study water adsorption on rutile surfaces. Monolayer and doublelayer water coverage was considered on the rutile (1 1 0) and (1 0 0) surfaces and the adsorbate structures were determined. Vibrational density of states of hydrogen atoms were calculated by constant temperature MD simulations at 100 K. These were used to interpret the experimental vibrational spectrum by assigning all peaks to the particular types of hydrogen atoms.     

二阶半线性常微分方程Robin边值问题的奇摄动

用基本方法讨论了一个半线性奇摄动Robin边值问题.利用微分不等式理论，证明了问题解的存在性，并得到了解的渐近估计.作为应用，给出了两个例子，一个是将结果应用于一个燃烧反应扩散问题的模型，另一个是得到了有关Dirichlet问题的相应结果.