Information preservation (IP) method in simulation of internal rarefied gas flows in MEMS

This paper reviews firstly methods for treating low speed rarefied gas flows: the linearised Boltzmann equation, the Lattice Boltzmann method (LBM), the Navier-Stokes equation plus slip boundary conditions and the DSMC method, and discusses the difficulties in simulating low speed transitional MEMS flows, especially the internal flows. In particular, the present version of the LBM is shown unfeasible for simulation of MEMS flow in transitional regime. The information preservation (IP) method overcomes the difficulty of the statistical simulation caused by the small information to noise ratio for low speed flows by preserving the average information of the enormous number of molecules a simulated molecule represents. A kind of validation of the method is given in this paper. The specificities of the internal flows in MEMS, i.e. the low speed and the large length to width ratio, result in the problem of elliptic nature of the necessity to regulate the inlet and outlet boundary conditions that influence each other. Through the example of the IP calculation of the microchannel (thousands m ? long) flow it is shown that the adoption of the conservative scheme of the mass conservation equation and the super relaxation method resolves this problem successfully. With employment of the same measures the IP method solves the thin film air bearing problem in transitional regime for authentic hard disc write/read head length ( 1000 L m ? = ) and provides pressure distribution in full agreement with the generalized Reynolds equation, while before this the DSMC check of the validity of the Reynolds equation was done only for short ( 5 L m ? = ) drive head. The author suggests degenerate the Reynolds equation to solve the microchannel flow problem in transitional regime, thus provides a means with merit of strict kinetic theory for testing various methods intending to treat the internal MEMS flows.

Comparative extraction of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F-s) from a variety of solid samples

Extraction experiments with spiking of C-13(12)-PCDD/Fs were performed with a variety of PCDD/Fs contaminated samples. The extraction recovery of PCDD/Fs was mainly influenced by PCDD/Fs concentration and the sample matrix. Generally, the first soxhlet extraction with toluene has suitable recovery. From the selected samples, only FAMS4 and 5 which are fly ashes with high concentration, the recovery of the first soxhlet extraction with 24 hr. is low, but PCDD/Fs were almost completely removed after 72 hr. Copyright (C) 1996 Elsevier Science Ltd

PLANKTON AND SESTON STRUCTURE IN A SHALLOW, EUTROPHIC SUBTROPICAL CHINESE LAKE

The seasonal dynamics in the nutrient concentrations, chlorophyll-a amount (Chl-a), total algal volume (CV), Chl-a/CV ratio, seston structure were studied at two sampling stations in a shallow, highly eutrophicated subtropic lake (the Guozheng Hu area of the East Lake) on the plain of the middle basin of the Chang Jiang (the Yangtze River) of China. The lake ecosystem of the Guozheng Hu area is dominated by two planktivorous fishes (silver carp and bighead carp), phytoplankton and zooplankton. Macrophytes are extremely scarce in this area. Concentrations of the total dissolved nitrogen and phosphorus in the Guozheng Hu area in 1990 were very high. Fish yield, of which, more than 90 % was composed of silver carp and bighead carp in the Guozheng Hu area was very high (ca. 1140 kg/ha or 45.6 g/m3 in 1990). Grazing pressure by the fishes on the plankton community is considered to be rather strong. The annual average biomass of zooplankton was ca. 1/3 - 1/2 that of phytoplankton. On the average, dry matter in the living plankton only constituted ca. 3-7 % of the total dry seston, and plankton carbon only constituted ca. 5 - 10 % of the seston carbon. The present results indicate that, in the Guozheng Hu area of the East Lake, of the organic part of the seston, detritus is quantitatively an important constituent, while living plankton is only a very small component.

Design, simulation and testing of large area silicon drift detectors and detector array for X-ray spectroscopy

Large area (25 mm(2)) silicon drift detectors and detector arrays (5x5) have been designed, simulated, and fabricated for X-ray spectroscopy. On the anode side, the hexagonal drift detector was designed with self-biasing spiral cathode rings (p(+)) of fixed resistance between rings and with a grounded guard anode to separate surface current from the anode current. Two designs have been used for the P-side: symmetric self-biasing spiral cathode rings (p(+)) and a uniform backside p(+) implant. Only 3 to 5 electrodes are needed to bias the detector plus an anode for signal collection. With graded electrical potential, a sub-nanoamper anode current, and a very small anode capacitance, an initial FWHM of 1.3 keV, without optimization of all parameters, has been obtained for 5.9 keV Fe-55 X-ray at RT using a uniform backside detector.

Design, simulation and testing of large area silicon drift detectors and detector array for X-ray spectroscopy

Large area (25 mm(2)) silicon drift detectors and detector arrays (5x5) have been designed, simulated, and fabricated for X-ray spectroscopy. On the anode side, the hexagonal drift detector was designed with self-biasing spiral cathode rings (p(+)) of fixed resistance between rings and with a grounded guard anode to separate surface current from the anode current. Two designs have been used for the P-side: symmetric self-biasing spiral cathode rings (p(+)) and a uniform backside p(+) implant. Only 3 to 5 electrodes are needed to bias the detector plus an anode for signal collection. With graded electrical potential, a sub-nanoamper anode current, and a very small anode capacitance, an initial FWHM of 1.3 keV, without optimization of all parameters, has been obtained for 5.9 keV Fe-55 X-ray at RT using a uniform backside detector.

真菌单宁酶发酵五倍子和有机溶剂中酶法合成没食子酸丙酯的研究

本文报告了丝状真菌单宁酶发酵五倍子及有机溶剂中酶法合成没食子酸丙酯的研究。利用单宁和/或五倍子诱导丝状真菌产生单宁 酶的原理，借助二级发酵程序，对从天然源得到的75株菌进行了生物转化实验研究。选择出既能水解单宁或五倍子成没食子酸，又 能把没食子酸和丙醇合成没食子酸丙酯，而且生物催化活性都较高的1株菌，这株菌经初步鉴定为黑曲霉(Aspergillus niger No.17)。随后对它开展了产酶条件和参数优化实验，得出了最佳培养条件。立足于参数优化实验方案的基础上，经由液体培养发酵 制备单宁酶制剂，并把该酶通过化学手段共价结合到一种新型载体—聚乙烯醇和戊二醛反应生成的缩醛上，制备得到固定化单宁酶 。这种固定化生物催化剂在两种有机介质体系中都具有逆向催化合成没食子酸丙酯的能力。最后建立起来一条有效可行的微生物酶 法制备没食子酸的技术途径，没食子酸产率达到70%。对这种物质进行元素 分析：含C,49.45%;含H,3.63%。它的熔点为237℃～243 ℃，三种溶剂系统的TLC均只给出一个斑点。这些数据都与标准品一致。有机溶剂中酶法合成没食子酸丙酯的技术途径已经建立。 水溶性单宁酶在潜溶剂体系中也能催化上述酯化反应，反应混合物中的PG浓度为16.4mmol/L，制备薄层被用于分离反应混合物所含 的PG，这种产物被红外、质谱及三种溶剂系统的TLC等方法鉴定，确证为目标产物。在这一学位论文的实验研究过程中，还包括一 些生化分析方法的建立和应用，这些方法用于鉴定底物和产物及测定它们的浓度，其内容主要包括TLC定性/半定量分析、元素分析 、质谱、红外等手段的综合运用。本工作为开发我国特有的天然产物资源—五倍子的生物化工加工技术及非水相生物催化技术的开 发，提供了有用的基础数据资料，具有应用基础研究工作的重要性。In this thesis, the studies on the fermentation of Chinese gallotannin by filamentous fungi with tannase activity and enzymatic synthesis of propyl gallate(PG) in organic solvents were described through these biocatalysts. Based on the principles of induction enzyme, the tannase produced from filamentous fungi by adding tannic acid(TA) and/or Chinese gallotannin into media was investigated, and the screening experiments of bioconversion were done with 75 strains by means of a two-stage fermentation procedure. These strains were isolated with the enrichment culture technique from natural sources. Hence we selected one strain (Aspergillus niger No.17) that can not only catalyze the hydrolyses of TA and/or Chinese gallotannin into gallic acid(GA) in the liquid cultures, but also be used to synthesize PG from propanol and GA in the non-aqueous media. At the same time both of its biocatalytical activities were higher. This strain was calssified to be Aspergillus niger by the primary identification. Then optimum conditions for production of the tannase and its parameters were examined. In this way, one set of optimum culture conditions was selected. Making use of the optimum proposal, the tanase was prepared through a liquid fermentation procedure. The enzyme was convalently coupled to a new type of carrier which was made chemically from polyvinyl alcohol(PVA)and glutaraldehyde. The immobilized enzymes were able to synthesize PG reversely in two organic media. Finally, an effective enzymatic technique for production of GA was developed. The yield of GA products was up to 70%。Element analysis for this substance: calce: C, 49.42%; H, 3.56%; found: C, 49.45%, H, 3.63%. Its melting point was 237℃～ 243℃ and TLCs on three solvent systems gave only one spot respectively. These data were identical with theauthentic GA. The enzymatic synthesis of PG in organic solvents was extablished with reverse route of tannase catalytical hydrolysis. Aqueous enzyme perparation also catalyzed above esterification in a buffer system. The PG concentration in the reaction mixture was 16.4mmol/L. The reparative-scale TLC was used to isolate PG from the reaction mixture. This product separated was identified by IR, MS and TLC on three solvent systems. In this study of thesis, some biochemical analytical mehtods were developed and used to identify substrates and products, and to determinate their concentration. These methods, including TLC qualitative/half quantitative analysis, element analysis, MS, IR and so on, were useful, available and performable. This work provided basic data and information for developing the biochemical engineering and bio-processing of Chinese gallotannin-a special natural resource in China and the non-aqueous phase biocatalysis. Thus, this study possesses importance in the applied and basic research work.

Germ cell loss induced by C-12(6+) ion irradiation in young female mice

The ovaries of Kun-Ming strain mice (3 weeks) were irradiated with different doses of C-12(6+) ion in the Bragg peak or the plateau region. At 10th day after irradiation, ovarian and uterine weights were measured: normal and atretic (identified with the oocyte to be degenerating or absent) primordial, primary and preantral follicles were identified in the largest cross-section of each ovary. Percentage (%) of normal follicles of each developmental stage of oogenesis was calculated. The data showed that compared to controls, there was a dose-related decrease in percentage of normal follicles in each developmental stage. And the weights of ovary and uterus were also reduced with doses of irradiation. Moreover, these effects were much more significant in the Bragg peak region and the region close to the Bragg peak than in the beam's entrance (the plateau region). Radiosensitivity varied in different follicle maturation stages. Primordial follicles, which are thought to be extremely sensitive to ionizing irradiation, were reduced by 86.6%, while primary and preantral follicles reduced only by 72.5% and 61.8% respectively, by exposure with 6 Gy of C-12(6+) ion in the Bragg peak region and the region close to the Bragg peak. The data suggested that due to their optimal depth-dose distribution in the Bragg peak region, heavy ions are ones of the best particles for radiotherapy of tumors located next of vital organs or/and surrounded by normal tissues, especially radiosensitive tissues such as gonads.

1973年至2004年贵州喀斯特山区石漠化风险格局的变化——以普定后寨地下河流域中下游为例

以贵州省普定后寨地下河流域中下游为例,采用景观生态学的研究方法,利用多时相多数据源的遥感影像(1973年的航片、1995年的TM影像及2004年的SPOT-5影像),从不同等级石漠化风险的角度分析了研究区近30多年来的石漠化风险格局变化的特征,以期了解喀斯特高原山区的石漠化变化特征规律。结果表明:从景观水平上来看,整个区域的景观正在向程度更高的石漠化风险的方向发展,表现为极低度石漠化风险斑块的面积呈现出逐渐减少的趋势,而高度和极高度石漠化风险斑块的面积却呈现出不断增加的趋势;从斑块类型水平上来看,不同等级的石漠化风险斑块的变化差异明显,在变化幅度和变化趋势上都存在差异,其中极低度石漠化风险斑块面积变化最为明显,呈现出大幅度的下降,而变化最不明显的是低度石漠化风险斑块,无明显的增减趋势。

基于GIS的喀斯特高原山区石漠化景观格局变化分析

石漠化是广泛存在于中国西南地区的一种生态-地质灾害,目前已成为备受关注的研究热点和难点。为了解喀斯特高原山区石漠化景观的时空变化,以贵州省普定县南部的典型喀斯特高原山区后寨河流域为例,以3期遥感影像(1987年和1995年的TM影像与2004年的SPOT-5影像)作为数据源,借助于ArcGIS9.0等软件和数理统计分析方法,从石漠化强度分级的角度对近18a来石漠化的动态变化进行了研究。结果表明:从整体上来看,整个流域的石漠化出现扩展的趋势,其中前期(1987-1995年)的扩展速度为6.55hm2/a,后期(1995-2004年)的扩展速度为29.64hm2/a,扩展速度呈现增加的趋势。其中,轻度石漠化的面积呈现出先减少后增加的趋势;而中度石漠化和强度石漠化的面积均呈现出逐渐增加的趋势。

喀斯特高原山区的景观格局变化垂直分异性——以贵州省普定后寨地下河流域中下游为例

利用多时相多数据源遥感影像数据(航片、TM影像及SPOT-5影像),采用GIS空间分析技术和数理统计分析相结合的方法,以贵州省普定县后寨地下河流域中下游地区为例,从海拔和坡位2个方面来探讨喀斯特地区的景观格局变化的垂直分异特征。结果表明:林地斑块在海拔范围为1300~1350 m及1450~1550 m的区域内,变化是最大的;水田和旱地斑块在海拔范围为1219~1300 m及1350~1450 m的区域内,变化最大。景观格局在山脊和谷底内变化相对较大,其中变化最大的是林地斑块;景观格局在陡坡和缓坡地区的变化相对较小,但是也存在一定的变化,该区域中变化较大的为水田和旱地斑块。在海拔范围为1300~1500 m的山脊和谷底区域内,景观斑块类型发生的变化较大。该区域应作为喀斯特高原山区的生态环境保护特别关注的区域。

辽宁东部山区林地生态分类系统

以数字高程模型和SPOT-5遥感数据为数据源,通过地理信息系统的空间分析,在辽宁东部山区有代表性实验区域内,完成了生态土地类型(ELT)和生态土地类型相(ELTP)两个等级的分类和绘图,构成了生态分类系统(ECS)等级结构中最低的两个层次.实验区域内共得到5种ELT和34种ELTP.ELT的划分以环境特征为基础,表征了植被分布的潜在状况和森林生态系统潜在的生产力.ELTP是对ELT的再划分,是生态分类系统的最小单元,相当于我国林业区划中的小班.ELTP既包含ELT中的环境信息又包含现存植被构成的信息,具有空间精准、生态学含义明确的优点.在森林管理活动中,采用ELTP代替小班可以从景观尺度科学地指导森林经营计划编制,调整森林管理方式,实现对森林生态系统的有效管理.

Studies on enzymological properties of antibody elicited by meso-tetra(alpha, alpha, alpha, alpha-O-phenylacetyl benzene)porphyrin

meso-Tetra (alpha, alpha, alpha, alpha-O-phenylacetyl benzene) porphyrin was used as a complete antigen to elicit monoclonal antibody 1F2 through the immunization and cell fusion techniques. McAb 1F2 obtained was demonstrated very pure by HPLC and MALDI/TOFMS. The retention time of McAb 1F2 was 2. 63 min. The subtype of McAb 1F2 was IgG2a. The relative molecular weight was 156 678. 8. When the McAb 1F2-porphyrin was formed, the maximal absorption of the porphyrin soret region had a redshift from 408 to 416 nm and hyperchromical effect, showing that the antigen-antibody combination was rigid and intense, and the abzyme constancy was high. But compared with HRP, the activity of the abzyme was only 4. 687 5 U/mg and 1. 899 % of that of HRP. Its K-m was 20. 29 mmol/L, k(cat) 396. 82 min(-1), k(cat)/K-m. 1. 955 7 X 10(4) L . mol(-1) . min(-1).

海洋藻类功能性蛋白质的纯化、鉴定及其应用的研究

使用膨化柱和离子交换或羟基磷灰石柱层析相结合的方法，分别从多管藻、坛紫菜及钝顶螺旋藻中分离纯化了R-藻红蛋白溶液和C-藻蓝蛋白。光谱检测及电泳分析结果证明完全符合经典的藻胆蛋白纯度标准。彭化床最突出的优点是克服了常规分离方法堵塞色谱柱的难题，纯化速度快、产量高、不需要常规色谱方法所要求的填料的平衡及粗提液的预处理，仅需一步操作就可以得到满足一般食品添加剂纯度要求的藻胆蛋白，极大地简化了后续的纯化程序，减少了分离纯化的步骤和时间，而其产率及纯度均高于常规的藻胆蛋白分离方法。这同时也降低了藻胆蛋白分离纯化的成本。 本文通过戊二醛或环氧氯丙烷交联的方法，合成了四种壳聚糖-氨基酸共聚小球。并选取吸附性好的戊二醛交联孔球和戊二醛交联微球系统测定了其对R-藻红蛋白和C-藻蓝蛋白的吸附和缓释性能。 纯化了藓羽藻中与其细胞器团聚密切相关的一种凝集素并进行了部分性质的鉴定。N端前15个氨基酸序列及LC-ESI-MS质谱分析结果证明此凝集素属于一种新的蛋白质族。实验证明，凝血活性与细胞器团聚活性并不完全依赖于此凝集素分子相同的结构域。 通过异双功能试剂SPDP处理藓羽藻凝集素使之衍生化，DTT处理R-PE在其分子内引入外源巯基，然后将活化的R-藻红蛋白与凝集素进行交联反应。交联产物经凝胶过滤纯化并检测，但电泳及荧光显微镜检测结果并不能证明交联探针的成功制备。

Electroabsorption modulator integrated with buried-ridge-stripe dual-core spot-size converter by quantum-well intermixing

A single shallow ridge electroabsorption modulator monolithically integrated with a buried-ridge-stripe dual-core spot-size converter at the input and output port was fabricated by combining quantum-well intermixing and dual-core integration techniques simultaneously, using only a two-step low-pressure metal-organic vapor phase epitaxial process, conventional photolithography, and a chemical wet etching process. The optical insertion loss of the modulator in the on-state and the dc extinction ratio between 0 and -3 V at 1550 nm was -7.5 and 16 dB, respectively. The 3-dB modulation bandwidth was more than 10.0 GHz in electrical-optical response.

5.2 GHz variable-gain amplifier and power amplifier driver for WLAN IEEE 802.11a transmitter front-end

A 5.2 GHz variable-gain amplifier (VGA) and a power amplifier (PA) driver are designed for WLAN IEEE 802.11a monolithic RFIC. The VGA and the PA driver are implemented in a 50 GHz 0.35 μm SiGe BiCMOS technology and occupy 1.12×1.25 mm~2 die area. The VGA with effective temperature compensation is controlled by 5 bits and has a gain range of 34 dB. The PA driver with tuned loads utilizes a differential input, single-ended output topology, and the tuned loads resonate at 5.2 GHz. The maximum overall gain of the VGA and the PA driver is 29 dB with the output third-order intercept point (OIP3) of 11 dBm. The gain drift over the temperature varying from -30 to 85℃ converges within±3 dB. The total current consumption is 45 mA under a 2.85 V power supply.