Conversion and Application of Streamline-Characteristic Coordinate System in Supersonic Flows

为了求解二维平面弯曲激波波后流场,讨论并发展了一系列基于流线-特征线坐标系变换的流场代数计算方法。该系列方法依据二维平面流场中气流角、静压沿特征; 线近似不变的特点,可快速求解平面弯曲激波波后流场。其中,等气流角近似法适合模拟流线轨迹,等静压近似法适合求解波后流场参数。在此基础上,又提出了一; 种改进的等气流角-等静压混合方法用于计算弯曲激波波后流场。和特征线法对比,等气流角-等静压混合法计算得到的流场基本特征与特征线法得到的结果相同,; 在来流马赫数Ma=6和Ma=4情况下误差分别仅为0.5%和0.15%,证实了该方法在求解二维平面弯曲激波流场中的适用性。In order to solve the two-dimensional planar flowfield behind the curved; shock,a series of algebraic methods are acquired at the; streamline-characteristic coordinate system. The main idea is that flow; angle and static pressure are approximately constant along each; characteristic line. In contrast to the Method of Characteristics,the; method of constant flow angle is good at calculating the streamline; trajectory while the method of constant static pressure is proper for; solving the flowfield parameters. A combined method named MCFP,Method of; Constant Flow-angle and Pressure,is afterwards proposed to better solve; the two-dimensional planar flowfield behind the curved shock. For a; relatively large Mach number range,the flowfield calculated by the MCFP; method is in good agreement with the MOC's. The error at incoming Mach; number 6 is 0.5% and the error at incoming Mach number 4 is 0.15%,which; demonstrates the applicability of the MCFP method.国家自然科学基金; 国防基础科研; 中央高校基本科研业务

An Inverse Method for Supersonic Flowfield with Given Downstream Boundary

为了实现超声速流场出口参数的可控设计,借鉴特征线方法在古尔赛特与柯西问题两类边值条件中的应用,提出了一种根据下游边界条件求解其依赖域的逆柯西问题求解方法,并在此基础上发展了一种均匀来流条件下的超声速流场逆向求解方法。对轴对称内收缩流场、二维平面流场、轴对称外锥流场三个典型算例校核表明,逆向求解方法得到的计算结果与正向特征线方法一致,由此验证了该逆向求解方法的可行性,并有效拓展了超声速流场的设计思路。For the controllable design of exit parameters in supersonic flowfield,a new method of solving the inverse Cauchy problem,referring to the Method of Characteristics applied in the Goursat and Cauchy problems,is proposed to calculate the domain of dependence according to known downstream condition. On this basis,an inverse method for supersonic flowfield with the uniform flow condition is further developed. The validation of three typical cases(axisymmetric internal compression flowfield,two-dimensional planar flowfield and external conical flowfield) shows that results obtained by the inverse method agree well with those obtained by forward MOC,which verifies the feasibility of the inverse method and expands the thought of supersonic flowfield design effectively.国家自然科学基金(51276151;91441128);; 国防基础科研(B1420133058);; 中央高校基本科研业务费(20720140540

Comparative Analysis of Complete Mitochondrial DNA Control Region of Four Species of Strigiformes

利用Long-PCR和PrimerWalking的方法对鸮形目的短耳鸮、长耳鸮、纵纹腹小鸮、灰林鸮4种鸟类的线粒体调控区进行了全序列测定。结果表明:短耳鸮的调控区长度为3290bp;长耳鸮为2848bp;纵纹腹小鸮为2444bp;灰林鸮为1771bp。短耳鸮的调控区长度是4种鸮中最大的,并且是目前已知最大的鸟类线粒体调控区。这4种鸮类调控区的基本结构和其他鸟类相似,按照碱基变化速率的不同可以分为3个区:碱基变化速率较快的外围区域Ⅰ、Ⅲ和保守的中间区域Ⅱ。这4种鸟类调控区的3′端均存在大量的串联重复序列,短耳鸮为126bp单元重复7次和78bp单元重复14次;长耳鸮为127bp单元重复8次和78bp单元重复6次;纵纹腹小鸮有3个重复单元,分别为89bp单元重复3次、77bp单元重复4次和71bp单元重复6次;灰林鸮仅有1个单元的串联重复为78bp重复5次。调控区中串联重复序列可能是由链的滑动错配产生,另外这些重复序列都能形成热力学稳定的多重茎环二级结构,而且在重复序列中还发现一些保守基序,这说明重复序列可能具有一定的生理功能,影响调控区的调控功能从而影响线粒体基因组的复制和转录。The sequence of the whole mitochondrial (mt) DNA control region (CR) of four species of Strigiformes was obtained. Length of the CR was 3 290 bp, 2 848 bp, 2 444 bp, and 1 771 bp for Asio flammeus, Asio otus, Athene noctua, and Strix aluco, respectively. Interestingly, the length of the control region was maximum in Asio flammeus among all the avian mtDNA control regions sequenced thus far. In addition, the base composition and organization of mtDNA CR of Asio flammeus were identical to those reported for other birds. On the basis of the differential frequencies of base substitutions, the CR may be divided two variable domains, Ⅰ and Ⅲ, and a central conserved domain, Ⅱ. The 3′ end of the CR contained many tandem repeats of varying lengths and repeat numbers. In Asio flammeus, the repeated sequences consisted of a 126 bp sequence that was repeated seven times and a 78 bp sequence that was repeated 14 times. In Asio otus, there were also two repeated sequences, namely a 127 bp sequence that was repeated eight times and a 78 bp sequence that was repeated six times. The control region of Athene noctua contained three sets of repeats: a 89 bp sequence that was repeated three times, a 77 bp sequence that was repeated four times, and a 71 bp sequence that was repeated six times. Strix aluco, however, had only one repeated sequence, a 78 bp sequence that was repeated five times. The results of this study seem to indicate that these tandem repeats may have resulted from slipped-strand mispairing during mtDNA replication. Moreover, there are many conserved motifs within the repeated units. These sequences could form stable stem-loop secondary structures, which suggests that these repeated sequences play an important role in regulating transcription and replication of the mitochondrial genome.This work was supported by the National Natural Sciences Foundation of China (No. 30470936)

脊椎动物线粒体DNA的基因重排

将GenBank上已公布的321种脊椎动物mtDNA全序列,按纲整理归类,绘制基因排布图并进行比对。 比对结果表明:81个物种的mtDNA中观察到基因重排现象,涉及脊椎动物各纲,其中9个物种同时存在基因顺序 变化和基因倒置现象,所有的基因重排都涉及tRNA的变化。脊椎动物mtDNA基因顺序变化可分为3类:1)邻接 的基因或片段的位置交换;2)接近于控制序列或轻链起始位点的基因或片段的位置变化,有时还伴随着控制序列 的倍增;3)I Q M区域的变化。所有鸟类、蛇类、鳄类和有袋类的mtDNA具有各自独特的基因排列顺序。基因倒 置现象常见于鱼类和哺乳类,且多表现为tRNA从轻链往重链上迁移。本文就这些基因重排现象、发生重排的机制 和mtDNA基因重排在系统发生研究中的应用做一简要概述。国家自然科学基金(编号:30170505,30470938);; 教育部骨干教师资助计划(编号:GG 180 21002403 1740);; 教育部留学回国人员启动基金资助~

The Characteristic of Calcium Distribution in Developing Female Gametophyte of Allium tuberosum

对韭开花前1 d到开花后2 d的发育胚囊中CA2+分布特征进行研究,结果显示:在开花前1 d游离核胚囊形成细胞,CA2+主要分布在极核周围的细胞质小液泡中,与中央细胞的大液泡形成有关;在开花当天,卵细胞大液泡体中CA2+增多,与其大液泡形成有关;开花后1 d,卵细胞大液泡中钙沉淀颗粒减少,助细胞珠孔段的CA2+增多,合点端较少,呈极性分布;开花后2 d,卵细胞大液泡和中央细胞大液泡珠孔部位CA2+再次明显增加。助细胞珠孔端丝状器中CA2+也增加,一个助细胞退化,呈现接受花粉管状态。韭发育胚囊中CA2+分布特征显示其参与调控胚囊细胞的分化,揭示雌配子体中CA2+分布的时空特征是深入研究胚囊细胞分化的基础。Characteristic of Ca2+ distribution in developing female gametophyte of Allium tuberosum was studied from 1 d before anthesis to 2 d a fter anthesis.At 1 d before anthesis, the nuclear embryo sac differentiates gametophyte cells.Calcium precipitates of young embryo sac were few and mainly located in the small vacuoles surrounding polar nuclei, suggesting Ca2+ relating with the formation of the large vacuole of central cell.At anthesis, the precipitates in large vacuole of egg increased, also suggesting Ca2+ relating with formation of the large vacuole of egg cell.At 1 d after anthesis, the precipitates in egg cell decreased and increased in synergid cells, in which the precipitates displayed polarity distribution: more in the micropyle end of the cell than in the chalazal end.At 2 d after anthesis, the precipitates in the large vacuole of egg and the micropyle part of central cell appeared again.The precipitates in filiform apparatus of both synergids also increased.One synergid cell degenerated, which prepared to accept pollen tube.The characteristic of calcium distribution in developing embryo sac of A.tuberosum suggests that Ca2+ may regulate cell differentiation of embryo sac.Exploring the spatial-temporal feature of Ca2+distribution in developing embryo sac is a base of further study of cell differentiation of embryo sac.国家自然科学基金(31170289); 公益性行业(农业)科研专项课题(200903016

不同区段HIV-1 env基因在Bac-to-Bac昆虫细胞杆状病毒表达系统中的表达及检测

利用昆虫细胞杆状病毒表达系统 ,将从一株HIV - 1阳性克隆质粒中获得的几个HIV包膜蛋白基因片段 ,克隆入转移载体中得到重组病毒。用此重组病毒感染昆虫细胞后表达出 3种HIV包膜蛋白 ,即GP12 0 - 41P、GP41T、GP41P ,分别含有HIV - 1包膜糖蛋白GP12 0及部分GP41,删除了N端 12个疏水氨基酸的GP41和仅有主要表位约 2 40个氨基酸的GP41。收获后分别以Western -blotting和EIA检测 ,有较好的免疫学活性 ,其中GP41T的活性最强。该实验为HIV包膜蛋白的结构研究提供了依据 ,加以改进后可能有免疫检测的价值

Surface Plasmon-coupled Emission of Multicolor Quantum Dots

E-mail: [email protected][中文文摘]以巯基小分子为配体水相合成CdTe量子点,通过调节回流时间调控其粒径大小.由于量子点的宽谱激发特性,在蓝光(473 nm)或绿光(532 nm)条件下,纳米金属薄膜表面不同发射波长的CdTe量子点均可被激发而与金属表面等离子体发生耦合相互作用,从而在棱镜一侧发出高度定向的偏振荧光,其荧光特性与样品厚度密切相关.表面等离子体耦合荧光发射法(SPCE)具有波长分辨性质,不同颜色的量子点在不同角度定向发射,发射波长越长,角度越小.720nm和630 nm量子点的自由空间发射荧光光谱呈现交叠,然而,基于SPCE的波长分辨性质,我们通过改变检测角度避开光谱重叠,在棱镜一侧的43o和51o处分别得到了两种量子点的SPCE荧光单峰.量子点是SPCE在多通路、高通量检测应用中荧光物种的理想选择.[英文文摘]Aqueous CdTe quantum dots(QDs) were synthesized employing thiols as stabilizing ligands and their emission wavelengths could be tuned by controlling the reflux time.Surface plasmon-coupled emission(SPCE) properties of multicolor CdTe QDs were studied by using a laboratory-built multifunctional spectrofluorimeter.To fabricate a CdTe QDs-doped complete film onto the surface of continuous thin metal films,CdTe QDs were spin-coated at 3000 r/min with poly(vinyl alcohol)(PVA) solution of various concentrations.For SPCE measurements, the spin-coated slides were attached to a semi-cylindrical prism made of fused silica with a refractive-index-matching fluid and then positioned on a precise rotary stage that allowed for excitation and emission observation at any angle relative to the vertical axis of the stage. For excitation, we used the reverse Kretschmann (RK) configuration and the incident light was normal to the sample interface. The spectra were measured using a monochromator equipped with a photomultiplier tube. The experimental results showed CdTe QDs located nearby continuous thin metal film could be excited using either blue (473 nm) or green (532 nm) laser as a result of their broad excitations and their emissions resulting from the surface plasmon coupling were strongly directional, highly polarized and closely related to sample thickness. Because of the wavelength-resolution property of SPCE, CdTe QDs with different emission wavelengths were found to emit at different fixed angles, longer wavelengths corresponding to smaller angles. The free space emission spectra of 720 nm and 630 nm CdTe QDs in a mixture were overlapped and could not be separated at any detection angle. However, owing to the unique wavelength resolution ability of SPCE, the spectra of 720 nm and 630 nm CdTe QDs were obtained at 43° and 51º on the prism side, respectively. The determination of each component of the mixtures of CdTe QDs was achieved by changing the detection angle to avoid spectral overlap. Therefore, QDs are ideal fluorophores for SPCE in high-throughput, multiplex analysis application.国家自然科学基金(Nos.21127005,20975084); 国家973计划(No.2013CB933703); 教育部博士点基金(No.20110121110011)资

HIV-1 gp160截短蛋白在酿酒酵母中的表达

利用PCR技术从pNL-43上扩增出截短的编码gp160蛋白的基因片断,克隆到酿酒酵母表达载体YEpFLAG-1上构建表达质粒YEp-gp160Δ12,电转化到酿酒酵母中,用缺色氨酸的SC培养基筛选出阳性克隆,重组子经YP培养基诱导后进行全菌蛋白的SDS-PAGE和Western Blotting分析,筛选出高表达菌株.纯化后的重组gp160Δ12(rgp160Δ12)蛋白经ELISA鉴定显示具有良好的生物活性

The Analysis and Assessment of Groundwater Quality of Qinhuangdao

针对秦皇岛市地下水位下降,环境污染日益严重的现实,开展了以海水入侵区为主的地下水质综合评价与分析。在全市境内布设76眼监测井,用单因子法和综合法对地下水质量进行了评价,并对地下水水质变化趋势进行了分析。研究结果表明:Ⅰ类水只占5.3%,Ⅱ、Ⅲ水占14.5%,Ⅳ类及超Ⅳ类水占到80%以上,其中Ⅴ类水占40%。主要污染物有Fe、Mn、NO3-N、Cl、总硬度等。地下水质监测动态变化显示:总硬度、Cl-、矿化度、F-等呈上升趋势,其中总硬度和Cl-上升达75%,说明海水入侵的影响很大。To conter the situation of increasingly declining groundwater level and environmental pollution,the water quality assessment and analysis of sea water invasion district was studied.76 monitoring wells were laid,a single index method and the method of the comprehensive evaluation were used and the groundwater trends was analyzed.The results showed that the shallow groundwater of Qinhuangdao City meeting the Ⅰcategory water standard accounted for only 5.3%,Ⅱ,Ⅲcategories 14.5%,Ⅳ,Ⅴcategories more than 80%,40% of which wasⅤcategories and that Fe,Mn,NO3-N,Cl,total hardness were the major chemical components.The dynamics monitoring of underground water indicated that total hardness,chlorine,degree of mineralization,fluorine are becoming upward trend,especially total hardness and chlorine increased by over 75%, which means salt water intrusion on the larger impact.河北省自然基金项目(301165

Miniaturization of surface plasmon coupled emission spectrofluorimeter and its performance analysis

搭建了结构紧凑简单、性能稳定、成本低廉的表面等离子体耦合荧光(SPCE)小型装置。通过对罗丹明S101样品荧光信号角度分布和偏振性的测试,分析了该小型装置的仪器性能,结果令人满意。该装置完全能够满足SPCE一般的测试要求,可望推广使用。国家自然科学基金(21127005,20975084);教育部博士点基金(20110121110011)资