含小孔光阑的谐振腔选模优化设计

本文从全衍射理论出发，建立小孔选模腔的计算模型并设对出相应的优化软件包。该软件可直接对圆形反射镜构成的小孔腔进行关于小孔位置和孔径大小的优化计算，并研究小孔选模腔的选模特性随小孔位置和孔径变化的规律。     

高效液相色谱-紫外/质谱检测法联合测定新鲜烟叶中的25种酚类物质

建立了烟叶中25种酚类物质的高效液相色谱-紫外/质谱(HPLC-UV/MS)测定方法,其中11种主要酚类物质采用HPLC-UV法进行绝对定量分析,其余采用HPLC-MS法进行半定量分析。方法验证结果表明：11种酚类标准物质在0.90~99.00 mg/L(绿原酸及芸香苷为0.95~380.00 mg/L)范围内呈现很好的线性关系,相关系数为0.9993~0.9999。在22.5~24.8、45.0~49.5、67.5~74.3 mg/L 3个水平的加标回收率为91.0%~112.4%。方法重复性的相对标准偏差(RSD)为1.48%~13.40%,日内日间精密度的RSD为0.35%~15.54%。采用本方法对云南、河南、贵州的成熟期新鲜烟叶样品进行了分析,主要酚类物质总量为贵州>云南>河南,贵州与河南两地间存在显著性差异;芸香苷含量为云南>贵州>河南,且相互间有显著性差异。本方法预处理简单,酚类物质的分析覆盖面广,可用于批量烟叶样品的检测。     

Gas Dynamics in Thermal Nonequilibrium¶and General Hyperbolic Systems¶with Relaxation

We study gas flow in vibrational nonequilibrium. The model is a 4Ǹ nonlinear hyperbolic system with relaxation. Under physical assumptions, properties of thermodynamic variables relevant to stability are obtained, global existence for Cauchy problems with smooth and small data is established, and large time behavior is studied in the pointwise sense. We formulate the fundamental solution in a systematic way for a general linear system with relaxation. The fundamental solution provides insights to the behavior of the nonlinear system, and is crucial to obtain our pointwise asymptotic picture for the nonequilibrium flow. We also clarify in a general setting the relation between subcharacteristic conditions and a dissipative criterion that was originally proposed for hyperbolic-parabolic systems and has now proved to be important also for hyperbolic systems with relaxation.     

Electrocatalytic oxidation of formic acid on functional MWCNTs supported nanostructured Pd–Au catalyst

In this work, PdAu nanocatalysts with different weight ratio of Pd and Au supported on functional multi-walled carbon nanotubes (f-MWCNTs) were prepared, and their electrocatalytic activity for the oxidation of formic acid was also studied. The electrocatalysts were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The electrochemical results showed that the 4Pd1Au/f-MWCNTs (by weight) catalyst, exhibited distinctly higher activity and better stability in formic acid electrooxidation than the Pd/f-MWCNTs catalyst. The Nano-Au improves potentially the performance of Pd-based electrocatalysts for the direct formic acid fuel cells (DFAFCs).     

液化天然气冷能发电效益分析

通过分析LNG的温焓、温熵特性和不同压力下的可用能,揭示LNG冷能发电循环效率最大化原则和影响可用能利用率因素。同时对实际有机朗肯+直接膨胀复合循环进行参数计算,分析循环在不同压力下的LNG冷源条件下的效率及变化特点,并与不可逆卡诺循环和普通朗肯循环进行比较。结果表明,各种循环都存在一个最佳LNG冷能利用温度,使得循环性能最佳,而且随着LNG汽化压力的增大,循环效率呈下降趋势。在LNG汽化压力较高的情况下,回收直接膨胀功使得复合循环的效率及可用能利用率明显优于普通有机朗肯循环。     

推广的Mycielski图和类推广的Mycielski图的(邻点可区别的)全染色

Mycielski图是在1955年由Mycielski首先提出的,推广的Mycielski图是在2003年由Peter Che Bor Lam,林文松等给出的Mycielski图的一个自然推广,且研究了它的圆色数.目前关于推广的Mycielski图性质以及它们在点色数,分数色数,圆色数等方面已有许多研究.本文定义了推广的Mycielski图的另一推广称为类推广的Mycielski图,且探讨了推广的Mycielski图和类推广的Mycielski图在全染色、邻点可区别全染色方面与原基础图的关系,从而也得到了它们满足全染色猜想和邻点可区别全染色猜想及它们达到全色数和邻点可区别的全色数的下界的一些充分条件.     

Screening the anti‐allergic components in Saposhnikoviae Radix using high‐expression Mas‐related G protein‐coupled receptor X2 cell membrane chromatography online coupled with liquid chromatography and mass spectrometry

Saposhnikoviae Radix, the dried root of Saposhnikoviae divaricata, is commonly used in the traditional Chinese anti‐allergic preparations, like Bofutsusho‐san and Yupingfeng granules. A high‐expression Mas‐related G protein‐coupled receptor X2 cell membrane chromatography coupled online with high‐performance liquid chromatography combined with an ion trap time‐of‐flight multistage mass spectrometry system was established and used for screening and identifying the anti‐allergic components in Saposhnikoviae Radix. The system was validated for excellent specificity and suitability using the appropriate standards. Two retained fractions were obtained on the cell membrane chromatography column, and three main components were identified as prim‐O‐glucosylcimifugin, cimifugin, and 4′‐O‐β‐d ‐glucosyl‐5‐O‐methylvisamminol. Next, the molecular docking study was conducted, which confirmed that these three components could effectively bind to MRGPRX2 through hydrogen bonds with its amino acid residues. Finally, histamine release assay was performed to investigate the bioactivities of prim‐O‐glucosylcimifugin, cimifugin, and 4′‐O‐β‐d ‐glucosyl‐5‐O‐methylvisamminol. Results showed that these three components could exert anti‐allergic effects by inhibiting the histamine release in a dose‐dependent manner (from 10 to 100 µM). In conclusion, the high‐expression Mas‐related G protein‐coupled receptor X2 cell membrane chromatography is an effective tool for discovering the anti‐allergic components in Saposhnikoviae Radix.     

L1 asymptotic behavior of compressible,isentropic, viscous 1-D flow

We study the large time behavior in L¹ of the compressible, isentropic, viscous 1-D flow. Under the assumption that the initial data are smooth and small, we show that the solutions are approximated by the solutions of a parabolic system, and in turn by diffusion waves, which are solutions of Burgers equations. Decay rates in L¹ are obtained. Our method is based on the study of pointwise properties in the physical space of the fundamental solution to the linearized system. © 1994 John Wiley & Sons, Inc.     

镍掺杂的镁(0001)面上氢气解离的密度泛函理论研究

采用密度泛函理论研究了氢气在镍掺杂的镁(0001)面上的解离吸附过程.通过固定键长法计算得到氢分子在镍掺杂的镁(0001)面上的解离能垒为0.09eV,而在清洁镁(0001)面上,氢气的解离能垒为1.15eV.电子结构分析表明,解离能垒的降低是由于氢分子与表面镍原子形成反馈键并被填充所致.这一计算结果表明,在镁中加入过渡金属催化剂会大大提高储氢材料的动力学性能.     

Regioisomerism effect (RIE) on optimizing ultralong organic phosphorescence lifetimes

Regioisomerism effect was disclosed on optimizing ultralongorganic phosphorescence life times of three crystalline dicarbazol-9-yl pyrazine-based regioisomers (p-DCzP,m-DCzP,and o-DCzP) with para-,meta-, and ortho-convergent substitutions.It is revealed that regioisomerism effect could be an effective strategy for the deep understanding of UOP materials.