Experimental Study Of Multi-Hole Cooling For Integrally-Woven, Ceramic Matrix Composite Walls For Gas Turbine Applications

In this paper, multi-hole cooling is studied for an oxide/oxide ceramic specimen with normal injection holes and for a SiC/SiC ceramic specimen with oblique injection holes. A special purpose heat transfer tunnel was designed and built, which can provide a wide range of Reynolds numbers (10(5)similar to 10(7)) and a large temperature ratio of the primary flow to the coolant (up to 2.5). Cooling effectiveness determined by the measured surface temperature for the two types of ceramic specimens is investigated. It is found that the multi-hole cooling system for both specimens has a high cooling efficiency and it is higher for the SiC/SiC specimen than for the oxide/oxide specimen. Effects on the cooling effectiveness of parameters including blowing ratio, Reynolds number and temperature ratio, are studied. In addition, profiles of the mean velocity and temperature above the cooling surface are measured to provide further understanding of the cooling process. Duplication of the key parameters for multi-hole cooling, for a representative combustor flow condition (without radiation effects), is achieved with parameter scaling and the results show the high efficiency of multi-hole cooling for the oblique hole, SiC/SiC specimen. (C) 2008 Elsevier Ltd. All rights reserved.

Measuring Receptor/Ligand Interaction at the Single-Bond Level: Experimental and Interpretative Issues

There is increased interest in measuring kinetic rates, lifetimes, and rupture forces of single receptor/ligand bonds. Valuable insights have been obtained from previous experiments attempting such measurements. However, it remains difficult to know with sufficient certainty that single bonds were indeed measured. Using exemplifying data, evidence supporting single-bond observation is examined and caveats in the experimental design and data interpretation are identified. Critical issues preventing definitive proof and disproof of single-bond observation include complex binding schemes, multimeric interactions, clustering, and heterogeneous surfaces. It is concluded that no single criterion is sufficient to ensure that single bonds are actually observed. However, a cumulative body of evidence may provide reasonable confidence. 0 2002 Biomedical Engineering Society.

Optimization of biodiesel production from trap grease via acid catalysis

As a kind of waste collected from restaurants, trap grease is a chemically challenging feedstock for biodiesel production for its high free fatty acid (FFA) content. A central composite design was used to evaluate the effect of methanol quantity, acid concentration and reaction time on the synthesis of biodiesel from the trap grease with 50% free fatty acid, while the reaction temperature was selected at 95 degrees C. Using response surface methodology, a quadratic polynomial equation was obtained for ester content by multiple regression analysis. Verification experiments confirmed the validity of the predicted model. To achieve the highest ester content of crude biodiesel (89.67%), the critical values of the three variables were 35.00 (methanol-to-oil molar ratio), 11.27 wt% (catalyst concentration based on trap grease) and 4.59 h (reaction time). The crude biodiesel could be purified by a second distillation to meet the requirement of biodiesel specification of Korea.

Solid-state electrochemiluminescence of tris(2,2 '-bipyridyl) ruthenium

Electrochemiluminescence (ECL) of tris(2,2'-bipyridyl) ruthenium [Ru(bpy)(3)(2+)] has received considerable attention. By immobilizing Ru(bpy)(3)(2+) on an e electrode surface, solid-state ECL provides several advantages over solution-phase ECL, such as reducing consumption of expensive reagent, simplifying experimental design and enhancing the ECL signal.This review presents the state of the art in solid-state ECL of Ru(bpy)(3)(2+).

Analytical applications of the electrochemiluminescence of tris (2.2 '-bipyridyl) ruthenium and its derivatives

This article presents the state of the art of analytical applications of the electrochemiluminescence (ECL) of tris (2,2'-bipyridyl) ruthenium (Ru(bpy)(3)(2+)) and its derivatives. in the last seven years, Ru(bpy)(3)(2+) ECL has attracted much interest from analysts and been successfully exploited as a detector of flow injection analysis (FIA), high-performance liquid chromatography (HPLC), capillary electrophoresis (CE), and micro total analysis systems (TAS). Immobilization of Ru(bPY)(3)(2+) on a solid surface provides several advantages over the solution-phase ECL procedure, such as the simplicity of experimental design and cost-effectiveness. After a brief discussion of the mechanism of Ru(bpy)(3)(2+) ECL, we discuss its applications in FIA, HPLC, CE and TAS and give special attention to the design of Ru(bpy)(3)(2+) ECL cells and some immobilization techniques of Ru(bpy)(3)(2+); we focus on papers published after 1997.

Livestock grazing, plateau pikas and the conservation of avian biodiversity on the Tibetan plateau

On the Qinghai-Tibet plateau increased livestock numbers have resulted in degradation of the grasslands with potential impacts on native biodiversity. Concurrently, perceived increases in populations of native small mammals such as plateau pikas (Ochotona curzoniae) have led to poisoning programs, with uncertain impacts on species such as ground-nesting birds. We explored the relationships between the local seasonal abundance of small birds and (1) the density of pika burrows; (2) livestock grazing practices; and (3) local poisoning of pikas. Around Naqu prefecture, central Tibet, we used a nested experimental design to collect data from areas rested from grazing over summer, nearby areas with year-round grazing and areas subjected to pika poisoning. Additional data were collected from a site where grazing had not occurred for at least 4 years prior to the study. Poisoning pikas in spring had no detectable effect on the local abundance of birds the following autumn. However, two ground-nesting species, white-rumped and rufous-necked snowfinches, showed positive associations with the density of pika burrows, indicating that long-term 'pika poisoning could reduce the density of these species by reducing the density of pika burrows. Rufous-necked snowfinches and non ground-nesting species including horned larks and common hoopoes showed positive responses to reduced grazing pressure from livestock, particularly in the long-rested site, indicating current grazing levels could be having a negative impact on these species. Conservation of small passerine biodiversity in this system will require changed management practices for livestock and pikas that consider the complex three-way interaction between livestock grazing, pikas and small birds. (C) 2008 Elsevier Ltd. All rights reserved.

On a novel method of impact by a front-end-coated bullet to evaluate the interface adhesion between film and substrate

A preliminary experiment was carried out to validate the feasibility of the method of impact by a front-end-coated bullet to evaluate the interface adhesion between film and substrate. The theoretical description of the initiation, propagation and evolution of the stress pulse during impact was generalized and formulized. The effects of the crucial parameters on the interface stress were further investigated with FEM. The results found the promising prospect of the application of such a method and provided useful guidance for experimental design.

瑞香狼毒（Stellera chamaejasme L.）对高寒草甸系统生长和非生长季节碳氮循环的影响及其花粉化感效应

瑞香狼毒（Stellera chamaejasme L.）是瑞香科（Thymelaeaceae）狼毒属的一种多年生野草，有毒。据调查，从20 世纪60 年代开始至今，狼毒在青藏高原东缘的高寒草甸上不断蔓延、密度不断变大，在一些地段甚至成为优势物种。有关狼毒在高寒草甸蔓延的生态系统效应的研究尚未见报道。本文从系统碳、氮循环的角度，分别研究狼毒在生长和非生长季节对高寒草甸生态系统的影响。同时，从花粉化感的角度，深入研究狼毒对当地同花期物种有性繁殖的影响。系统地研究高寒草甸生态系统物质循环过程，特别是非生长季节微生物和土壤碳氮库的动态变化，有助于揭示狼毒在系统物质循环方面的“物种效应”以及这种效应的季节变化，为丰富有关高海拔生态系统，特别是其非生长季的物质循环的科学理论做出贡献。同时，碳氮循环和花粉化感的研究还有助于深刻地理解狼毒作为一种入侵性很强的杂草的特殊的蔓延机制，从而为狼毒的有效防治、高寒草甸的科学管理提供依据。 针对狼毒在青藏高原高寒草甸上蔓延的生态系统碳氮循环方面的影响，开展以下2 方面的研究：（1）在生长季，研究松潘县尕米寺附近（北纬32°53'，东经103°40'，海拔3190 m）的两种地形（平地和阳坡）条件下狼毒对土壤碳氮循环影响及可能的原因。狼毒和其它几个主要物种（圆穗蓼（Polygonummacrophyllum D. Don var. Macrophyllum），草地早熟禾（Poa pretensis L.），四川嵩草（Kobresia setchwanensis Hand.-Maizz.），鹅绒委陵菜（Potentilla anserina L.var. anserine）和鳞叶龙胆（Gentiana squarrosa Ledeb.）的地上凋落物产量以及地上凋落物和根的化学组成被测量。在有-无狼毒斑块下，各种土壤的库（比如，铵态氮、硝态氮、无机磷和微生物生物量）和周转率（包括净矿化、净硝化、总硝化、反硝化和微生物呼吸速率）被测量和比较。（2）在非生长季节，尤其是春季冻融交替期，选取了两个研究地点——尕米寺和卡卡沟（北纬32°59'，东经103°41'，海拔3400 m），分别测定有狼毒和无狼毒斑块下土壤微生物生物量碳和氮、可溶性有机碳和氮以及铵态氮和硝态氮的动态变化。同时，分别在上述两个地点有-无狼毒的样地上，研究6 个主要物种（狼毒、圆穗蓼、草地早熟禾、四川嵩草、鹅绒委陵菜和鳞叶龙胆）从秋季开始、为期1 年的凋落物分解过程。 针对狼毒花粉化感对同花期其它物种可能的花粉化感作用开展以下工作：在实验室中，用一系列浓度的狼毒花粉水浸提液对与它同花期的其它物种以及自身花粉进行测试，测定花粉萌发率；在野外自然条件下的其它物种的柱头上施用上述浓度的狼毒花粉水浸提液，观测种子结实率，同时，观察狼毒花粉的种间花粉散布数量。 生长季节的研究结果表明，狼毒地上凋落物氮含量比其它几个主要物种更高，而木质素-总氮比更低。狼毒显著地增加其斑块下表层土壤中有机质的含量，而有-无狼毒的亚表层土壤在有机碳和总磷方面没有显著差异。狼毒表土中硝态氮含量在平地和阳坡比无狼毒土壤分别高113%和90%。狼毒表土中微生物生物量碳和氮量显著高于无狼毒表土。无论是平地还是阳坡，狼毒土壤的总硝化和微生物呼吸速率显著高于无狼毒土壤；而它们的反硝化速率只在平地有显著的差异。狼毒与其它物种间地上凋落物的产量和质量的差异可能是导致有-无狼毒土壤碳氮循环差异的原因。我们假设，狼毒可能通过增加贫氮生态系统土壤中的有效氮含量提高其入侵能力。 非生长季的研究结果表明，在青藏高原东缘的高寒草甸上，土壤微生物生3物量在11 月的秋-冬过渡期达到第一个峰值；在春季的冻融交替期，微生物生物量达到第二个峰值后又迅速降低。无机氮以及可溶性有机碳氮与微生物生物量有相似的变化过程。微生物碳氮比呈现显著的季节性变化。隆冬季节的微生物生物量碳氮比显著高于生长旺季的微生物碳氮比。这种变化可能暗示冬、夏季微生物的群落组成和对资源的利用有所不同。有-无狼毒斑块下土壤微生物和土壤碳、氮库一般只在秋-冬过渡期有显著差异，有狼毒土壤微生物生物量和土壤碳、氮库显著高于无狼毒土壤；而在之后的冬季和春季没有显著差异。所有6 个物种凋落物在非生长季分解率为24%-50%，均高于生长季的10%到30%。其中在秋-冬过渡期，凋落物开始埋藏的两周时间内，分解最快，达10%-20%。不同物种凋落物全年的分解率和分解过程有显著差异。圆穗蓼在全年的分解都较缓慢（非生长季26%，生长季15%），草地早熟禾和四川嵩草等全年的分解速率比较均匀（非生长季和生长季均为30%，非生长季略高），而狼毒在非生长季分解较快（约50%），而在接下来的生长季分解变得缓慢（约12%）。所有物种的凋落物氮含量在非生长季下降，而在随后的生长季上升。 实验室的花粉萌发试验证明，狼毒花粉对自身花粉萌发没有自毒作用，而其它受试的所有物种（圆穗蓼，秦艽（Gentiana macrophylla Pall. var. fetissowii），湿生扁蕾（Gentianopsis paludosa (Hook. f.) Ma var. paludosa），鳞叶龙胆，椭圆叶花锚（Halenia elliptica D. Don var. elliptica），蓝钟花（Cyananthus hookeri C. B.Cl. var. grandiflorus Marq.），小米草（Euphrasia pectinata Ten.），川西翠雀花（Delphinium tongolense Franch.），高原毛茛（Ranunculus tanguticus (Maxim.)Ovcz. var. tanguticus）和鹅绒委陵菜）的花粉萌发率随着狼毒花粉浸提液浓度的增加呈显著的非线性降低。大约3 个狼毒花粉的浸提液就可以抑制受试的多数物种的50%的花粉萌发。在鳞叶龙胆和小米草柱头上狼毒花粉的数量分别为5.76 个和3.35 个。狼毒花粉散布数量的差异最可能的原因在于是否有共同的传粉昆虫。花的形状（辐射对称VS 左右对称）、植株或花的密度以及花期重叠性可以部分解释这种差异。在野外试验中，我们发现6 个物种（秦艽、湿生扁蕾、鳞叶龙胆、椭圆叶花锚、蓝钟花和小米草）的种子结实率随狼毒花粉浸提液浓度的增加呈显著的非线性降低。鳞叶龙胆和小米草柱头上狼毒花粉的数量（分别是5.76 个和3.35 个）分别达到了抑制它们63%和55%种子结实率的水平。因此，狼毒对鳞叶龙胆和小米草可能存在明显的花粉化感抑制作用。狼毒周围的物种可能通过花期在季节或昼夜上的分异避免受到狼毒花粉化感的影响或者通过无性繁殖来维持种群繁衍，因此狼毒通过花粉化感作用对其周围物种繁殖的影响程度还需要进一步地研究。如果狼毒的花粉化感抑制作用确实存在，那么它可能成为一种自然选择压力，进而影响物种的进化。 Stellera chamaejasme L., a perennial toxic weed, has emerged and quicklydominated and spread in the high-frigid meadow on the eastern Tibetan Plateau ofChina since the 1960s. In the present study, effects of S. chamaejasme on carbon andnitrogen cycles on the high-frigid meadow on the eastern Qinghai-Tibetan Plateau ingrowing and non-growing season, and its pollen allelopathic effects on the sympatricspecies were determined. The present study that focused on carbon and nitrogencycles, especially on microbial biomass and pools of carbon and nitrogen innon-growing season, could profoundly illuminate plant-species effects on carbon andnutrient cycles and its seasonal pattern and help to understand spread mechanism ofS. chamaejasme as an aggressive weed. The present study also contributed to furtherunderstand carbon and nutrient cycles on alpine regions in non-growing season andprovide a basis on weed control of S. chamaejasme and scientific management in thehigh-frigid ecosystem. Effects of S. chamaejasme on carbon and nitrogen cycles on the high-frigidmeadow on the eastern Qinghai-Tibetan Plateau were determined. The study couldbe divided into two parts. (1) In the growing season, we quantified the effects of S.chamaejasme on carbon and nitrogen cycles in two types of topographic habitats, theflat valley and the south-facing slope, where S. chamaejasme was favored to spreadlitter and root were measured to explain the likely effects of S. chamaejasme on soilcarbon and nutrient cycles. The sizes of various soil pools, e.g. nitrite, ammonium,inorganic phosphorus and microbial biomass, and turnover rates including netmineralization, gross nitrification, denitrification and microbial respiration weredetermined. (2) In the non-growing season study, microbial biomass carbon andnitrogen, soluble organic carbon and nitrogen, ammonium and nitrate weredetermined through the non-growing season, especially in the processes offreeze-thaw of spring in two high-frigid sites, i.e. Kaka valley and Gami temple, onthe eastern Qinghai-Tibetan Plateau. Meanwhile, litter decomposition of six commonspecies, including Stellera chamaejasme L., Polygonum macrophyllum D. Don var.Macrophyllum, Poa pretensis L., Kobresia setchwanensis L., Potentilla anserina L.var. anserine and Gentiana squarrosa Ledeb., were also examined under theabove-mentioned experimental design through one whole-year, which began in theautumn in 2006. In the study of pollen allelopathy, several work, including in vitro study oneffects of extract of pollen from S. chamaejasme on sympatric species and pollenfrom itself, field experiments on effects of pollen extract with the same regime ofconcentrations on seed set and field observation on heterospecific pollen transfer ofS. chamaejasme to six of those sympatric species has been done. The results in the growing season showed that aboveground litter of S.chamaejasme had higher tissue nitrogen and lower lignin: nitrogen ratio than thoseco-occurring species. S. chamaejasme significantly increased topsoil organic matter,whereas no significant differences were found for organic C and total P in subsoilbetween under-Stellera and away-Stellera locations. The nitrate in Stellera topsoilwas 113% and 90% higher on the flat valley and on the south-facing slope,respectively. Both microbial biomass C and N were significantly higher in Stelleratopsoil. Gross nitrification and microbial respiration were significantly higher inStellera topsoil both on the flat valley and on the south-facing slope, whereassignificant differences of denitrification were found only on the flat valley. Thedifferences in the quantity and quality of aboveground litter are a likely mechanismresponsible for the changes of soil variables. We assumed that S. chamaejasme couldenhance their spread by increasing nutrient availability in N-deficient ecosystems. The results in the non-growing season showed that microbial biomass achievedthe first summit in late autumn and early winter on the eastern Qinghai-TibetanPlateau. In the stages of freeze-thaw of spring, microbial biomass firstly achieved thesecond summit and subsequently sharply decreased. Inorganic nitrogen, solubleorganic carbon and nitrogen had a similar dynamics with that of microbial biomass.Ratio of microbial biomass carbon and nitrogen had an obviously seasonal pattern.The highest microbial C: N were in the non-growing season, which weresignificantly higher than those in the growing season. The seasonal pattern inmicrobial biomass C: N suggested that large changes in composition of microbialpopulation and in resources those used by microbes between summer and winter.Generally, microbial biomass and pools size of carbon and nitrogen in Stellera soilwere significantly higher than those under adjacent locations in late autumn andearly winter, but there were not significant differences in winter and in spring. Litterof all the focal species (Stellera chamaejasme L., Polygonum macrophyllum D. Donvar. Macrophyllum, Poa pretensis L., Kobresia setchwanensis Hand.-Maizz.,Potentilla anserina L. var. anserine and G. squarrosa Ledeb.) decomposed about24%-50% in the non-growing season, which were higher than those in the growingseason (ranged from 10% to 30%). Litter decomposed 10%-20% within the first twoweeks in late autumn and early winter. Significant differences in the whole-yeardecomposition rate and in the processes of decomposition were found among species.Polygonum macrophyllum decomposed slowly through the whole year (26% and15% in the non-growing season and in the growing season, respectively). Certainspecies, such as P. pretensis L. and K. setchwanensis, decomposed at a similar rate(30% both in the non-growing and in the growing season, slightly higher in the8growing season than those in the growing season), whereas S. chamaejasmedecomposed more rapidly (about 50%) in the non-growing season and subsequentlydecomposition became slow (about 12%) in the growing season. Litter nitrogencontents of all the focal species firstly decreased in the non-growing season and thenincreased in the growing season. In vitro experiments of pollen allelopathy, the results showed that pollen from S.chamaejasme was not autotoxic, whereas pollen germination in all the sympatricspecies (Polygonum macrophyllum D. Don var. Macrophyllum, Gentianamacrophylla Pall. var. fetissowii, Gentianopsis paludosa (Hook. f.) Ma var. paludosa,Gentiana squarrosa Ledeb., Halenia elliptica D. Don var. elliptica, Cyananthushookeri C. B. Cl. var. grandiflorus Marq., Euphrasia pectinata Ten., Delphiniumtongolense Franch., Ranunculus tanguticus (Maxim.) Ovcz. var. tanguticus andPotentilla anserina L. var. anserina) decreased nonlinearly as the increasingconcentrations of extract of pollen from S. chamaejasme. Pollen Extract of threepollens from S. chamaejasme generally inhibited 50% pollen germination of most ofthe focal species. 5.76 and 3.35 pollens from S. chamaejasme were observed in fieldon stigmas of G. squarrosa and E. pectinata, respectively. Differences inheterospecific pollen transfer of S. chamaejasme could be attributed to the primaryreason whether they shared common pollinators. Flower morphology (e.g.zygomorphic or actinomorphic), plant or floral density and concurrence in floweringphonologies could explain, in part, the differences in heterospecific pollen transfer.In field experiments, the results showed that seed set in six sympatric species(Gentiana macrophylla Pall. var. fetissowii, Gentianopsis paludosa (Hook. f.) Mavar. paludosa, Gentiana squarrosa Ledeb., Halenia elliptica D. Don var. elliptica,Cyananthus hookeri C. B. Cl. var. grandiflorus Marq. and Euphrasia pectinata Ten.)decreased nonlinearly as the increasing concentrations of extract of pollen from S.chamaejasme. According to the nonlinear curves, the amounts of pollens from S.chamaejasme on stigmas of G. squarrosa and of E. pectinata (i.e. 5.76 grains and3.35 grains, respectively) could reduce 63% and 55% seed set of G. squarrosa and ofE. pectinata, respectively. Thus, allelopathic effects of S. chamaejasme on G.squarrosa and E. pectinata could be realistic. The sympatric species of S.chamaejasme could avoid pollen allelopathy of S. chamaejasme to sustainthemselves. This highlights the need to study how much pollen allelopathy in S.chamaejasme influences the sympatric species through divergence in seasonal ordiurnal flowering phonologies or through asexual reproduction. If pollen allelopathyin S. chamaejasme was confirmed, it could be as a pressure of natural selection andthus play an important role in species evolution.

PVA降解菌的产酶条件及特性研究

目前对PVA生物降解研究重点逐渐转移到对PVA降解菌和PVA降解酶的研究开发上，随着对PVA降解高效新菌株的不断发现和PVA降解酶作用机理和分泌机制的深入了解，利用高效微生物或酶法治理PVA这类高聚物的污染将具有较大的应用潜力。本论文研究工作正是基于这种客观条件下进行的，对本实验室前期分离的PVA降解菌株P1、共生菌B1+B2、Pa、Pb为研究对象，重点研究了菌株P1和共生菌B1+B2的产酶条件和产酶特性，验证找出了影响菌株P1产酶的生长因子，论证了菌株B1+B2的产酶特性，优化得出了菌株B1+B2的最佳产酶条件；然后对共生菌B1+B2的PVA降解酶的稳定性进行了研究；最后研究了最佳组合菌的产酶特性和最佳产酶条件。主要研究结果如下： 1 通过对菌株P1产酶因子的研究，找出了核黄素是菌株P1产酶的必须因子，在以淀粉为碳源时，核黄素只是产酶的必须因子，而不是菌体生长的必须因子；在以PVA为碳源时，核黄素既是生长的必须因子，也是产酶的必须因子，是菌株P1的生长因子。 2 对共生菌B1+B2的产酶条件和产酶特性进行了研究，并通过正交实验找出了影响菌株产酶的主要条件和菌株产酶的最佳条件。 3 对共生菌PVA降解酶的稳定性进行了研究，确定了影响酶稳定性的主要理化条件。 4 通过对菌株降解性能的比较，确定菌株Pa、Pb、共生菌、P1的作为组合菌的组成菌，然后通过复配实验确定出菌株的最佳组合为菌株Pa、P1、共生菌，最后通过正交实验确定最佳组合菌的最佳配比。 5对影响组合菌产酶的因素进行了研究，通过正交实验确定了影响组合菌产酶的主要因素和最佳产酶条件。 本文通过对PVA降解菌株产酶条件和特性的研究，旨在为PVA降解菌生产酶制剂及进一步优化PVA降解菌在PVA废水治理中的应用提供理论和应用依据。 Now the PVA-degrading bacteria and polyvinyl alcohol-degrading enzyme are the key studies on the PVA biological degradation. It has great application potential using special bacteria and enzyme to treat pollution of PVA, with some high efficient Strain and enzyme were found. The study of this paper was based on that objective condition. The stain P1, symbiotic bacteria B1+B2, stain Pa and strain Pb were studied .The conditions of enzyme production and enzyme production characteristic of stain P1, symbiotic bacteria B1+B2 were our key study, we tested and verified the growth factor which effected enzyme production of strain P1, demonstrated enzyme production characteristic of symbiotic bacteria B1+B2, optimized and obtained the optimum conditions of enzyme production; then we studied the stability of polyvinyl alcohol-degrading enzyme of strain B1+B2; last the enzyme characteristic and the optimum conditions of alcohol-degrading enzyme production of optimum combination stains were studied. The main study results are below: 1. Through the study of enzyme production factor we found that lactoflavin is the necessary factor in strain P1 enzyme production. When we used starch to be carbon energy, lactoflavin is only the necessary factor of enzyme production, but not growth factor. When we used PVA to be carbon energy, lactoflavin was not only the necessary growth factor ,but also the necessary enzyme production factor.So it was the growth factor of strain P1 2. The enzyme production conditions and enzyme production characteristic of symbiotic bacteria B1+B2 were studied. Through the orthogonal experimental design, the main conditions which effected the enzyme production and the optimum conditions of enzyme production were obtained 3. Through the study of the stability of polyvinyl alcohol-degrading enzyme, the main physical and chemical conditions which effected the enzyme stability were 4. The stain P1,symbiotic bacteria B1+B2, stain Pa and strain Pb were selected to form combination bacteria. The stain P1,symbiotic bacteria B1+B2,stain Pa were the optimum combination through duplication experiment. Then the optimum ratio was obtained through orthogonal experiment. 5. Studied the factors which effected the polyvinyl alcohol-degrading enzyme activity, then through orthogonal experiment, the main factors and condition of enzyme production which effected the combination bacteria were achieved. The result of the study was valuable for the ferment of the PVA-degrading enzyme and the optimization of the PVA-degrading performance in the PVA wastewater.

The study on a PVC membrane electrode for gemfibrozil

In this paper, a poly(vinyl chloride) (PVC) membrane electrode is prepared for gemfibrozil, 2, 2-dimethyl-5(2,5-xylyloxy) valeric acid, based on its ion pair complexes with hexadecyltrioctyl ammonium iodide (HTOA). The membrane composition of the electrode was optimized by using the sequential level elimination method for orthogonal experimental design. The electrode has a Nernstian response range from 2.5 X 10(-5) to 0.1 mol/l with an average slope of 55.3 mV/decade. The limit of detection is 7.1 X 10(-6) mol/l. The electrode responses were not affected by pH in the range 10.0-12.3. A Na2B4O7-Na2CO3 buffer of pH = 11.0 was selected as the background electrolyte solution for potentiometric measurements. The electrode was used for determining gemfibrozil in pharmaceutical preparations with satisfactory results.

趋磁细菌AMB-1培养条件优化及磁小体变化过程研究

趋磁细菌(Magnetotactic bacteria)的研究是国际微生物学研究热点之一。趋磁细菌体内含有纳米单磁畴的氧化铁/硫化铁(Fe3O4或Fe3S4)晶体，称为磁小体。由于趋磁细菌营养条件要求苛刻，在环境中需要微好氧条件，且营养类型属于化能自养，使得培养趋磁细菌时常遇到问题。 本研究首先通过正交试验优化趋磁细菌AMB-1菌株培养条件，在培养条件铁源为奎尼酸铁0.02 mmol/L，装瓶量75% ，pH值6.7，温度25 ℃时，AMB-1 OD600达到0.440(1.166×109 cells/ml)。同时运用磁收集传代法，使带有磁小体的AMB-1细胞比例占95％以上(Cmag值稳定在1.9-2.0)。 在AMB-1具有较好的生物量，同时又具有较好的含磁小体细胞比例后，研究磁小体的变化过程。通过透射电镜观察磁小体变化过程，发现培养24 h细菌体内已有较小晶体形成(平均27 nm，n=188)且沿长轴分布；48 h晶体长大(平均43 nm，n=203)且形成分段链沿长轴排列；72 h晶体进一步成熟(平均50 nm，n=191)仍以分段链沿长轴排列；随后细菌逐渐衰亡磁小体变小，168 h可见部分自溶细菌中仍有磁小体链(平均37 nm，n=186)；192 h细菌自溶磁小体链(平均33 nm，n=184)分散到环境中。 通过透射电镜在细胞水平上研究趋磁细菌细胞分裂时发现，磁小体在细菌分裂时采用两种分离方式：一种为磁小体分配到两个子细胞；另一种为磁小体只分配到一个子细胞。无磁小体的子细胞，在随后的生长过程又分为两种情况：一种为细胞逐渐产生磁小体，另一种为不再产生磁小体。这种现象的发现，解释了随着传代次数的增多，细菌磁性有所下降的原因(Cmag值降低)。 在对趋磁细菌磁小体合成机制的研究中，常使用基因敲除的办法获得缺陷型，并与野生型对比进行研究。但是，利用基因敲除获得缺陷型不仅操作繁琐并且所得缺陷型不稳定。本研究利用特殊的磁富集传代法，先将带有磁小体的菌体收集并连续传代，筛选获得了高磁菌株；利用这种方法，收集不含磁小体的菌体并连续传代，筛选获得了无磁菌株。 趋磁细菌磁小体在医疗、环保等领域具有广阔应用价值，但是目前由于趋磁细菌难以大规模培养，并且磁小体纯化存在成本高等原因，将磁小体真正实际应用尚有一段距离。通过研究磁小体在趋磁细菌中的变化过程发现，AMB-1菌株在培养192 h后自溶，并且磁小体随着细胞的破碎释放到环境中去。

Optimization and parameter study for chiral separation by capillary electrophoresis

Orthogonal design and uniform design were used for the optimization of separation of enantiomers using 2,6-di-O-methyl-beta-cyclodextrin (DM-beta-CD) as a chiral selector by capillary zone electrophoresis, The concentration of DM-beta-CD, buffer pH, running voltage, and capillary temperature were selected as variable parameters, their different effects on peak resolution were studied by the design methods. It was concluded that orthogonal design offers a rapid and efficient means for testing the importance of individual parameters and for determining the optimum operating conditions. However, for a large number of both factors and levels, uniform design is more efficient, The effect of addition of methanol and citric acid buffer on the separation of enantiomers was also examined.

真实和虚拟现实环境下场景识别中的空间更新

Currently，one of the important research areas in Spatial updating is the role of external (for instance visual) and internal (for instance proprioceptive or vestibular) information in spatial updating of scene recognition. Our study uses the paradigm of classic spatial updating research and the experimental design of investigation of Burgess(2004),first, we will explore the concrete influence of locomotion on scene recognition in real world; next, we will use virtual reality technology, which can control many spatial learning parameters and exclude the influence of extra irrelevant variables, to explore the influence of pure locomotion without visual cue on scene recognition, and furthermore, we will explore whether the ability of spatial updating can be transferred to new situations in a short period of time and compare the result pattern in real word with that in virtual reality to test the validity of virtual reality technology in spatial updating of scene recognition research. The main results of this paper can be summarized as follows： 1. In real world, we found two effects: the spatial updating effect and the viewpoint dependent effect, this result indicated that the spatial updating effect based on locomotion does not eliminate the viewpoint dependent effect during the scene recognition process in physical environment. 2. In virtual reality environment, we still found two effects: the spatial updating effect and the viewpoint dependent effect, this result showed us that the spatial updating effect based on locomotion does not eliminate the viewpoint dependent effect during the scene recognition process in virtual reality environment either. 3. The spatial updating effect based on locomotion plays double role in scene recognition: When subjects were tested in different viewpoint, spatial updating based on locomotion promoted scene recognition; while subjected were tested in same viewpoint, spatial updating based on locomotion had a negative influence on scene recognition, these results show us that spatial updating based on locomotion is automated and can not be ignored. 4. The ability of spatial updating can be transferred to new situations in a short period of time , and the experiment in the immersed virtual reality environment got the same result pattern with that in the physical environment, suggesting VR technology is a very effective method to do research on spatial updating of the scene recognition studies. 5. This study about scene recognition provides evidence to double system model of spatial updating in the immersed virtual reality environment.