南极产低温几丁质酶菌株的16S rDNA序列分析及其发酵条件及酶学性质研究

从南极深海沉积物中筛选到一株产低温几丁质酶的菌株AC444,经细菌形态观察及16S rDNA序列分析,该菌株属于假交替单胞菌属（pseudoalteromonas）,其最适与最高生长温度分别为15℃和30℃,属于兼性嗜冷菌。AC444菌株能利用多种碳源产酶,在含胶体几丁质和蛋白胨的培养基中产酶最高,达13．47U,最适产酶温度为20℃。酶的最适反应pH为7．0,最适作用温度为35℃,属中性低温酶。     

硫系高效脱臭菌的分离及其特性研究

从三个不同地点采集的混合样品中，分离到16株能氧化无机硫化物的菌株，优化筛选出菌株Hm-6，其形态，生理生化反应特征鉴定为假单菌（Pseudomonas sp.)。研究了菌株Hm-6氧化H2S的影响因素和代谢过程。确定Hm-6菌株的生长最适温度为30℃，pH值为7；将其投加到泥炭生物过滤塔中，室温即对低浓度H2S有较高的去除效果，且没有延迟期，代谢产物是类硫物质，而不是通常的硫酸根。     

深海适冷菌Pseudomonas sp.SM9913的适冷生长机制探讨

研究了温度对适冷菌Pseudomonas sp.SM9913的生长与适冷蛋白酶合成的影响，结果表明，P.sp.SM9913的最适生长温度为15℃，最适产酶温度为10℃，是一典型的适冷菌。P.sp.SM9913分泌的适冷蛋白酶在低温下与底物的亲和力增大，反应的活化能降低，表明在低温下较中温蛋白酶有更高的催化效率。深海产适冷蛋白酶的适冷菌P.SM9913可能是通过提高菌株在低温下的生长速率和增加酶分子在低温下的催化效率两条途径增加低温环境中蛋白质的分解效率，从而以适应低温环境。     

低温纤维素酶产生菌的筛选、鉴定、生长特性及酶学性质

从北极楚科奇海分离出一株产纤维素酶的耐冷假交替单胞菌BSw20308。研究表明：该菌最适生长温度10℃,35℃不生长;在pH7．0～8．0、含2．0％～3．0％NaCl的培养基条件下最适宜菌株生长与产酶;可溶性淀粉、酵母浸出液是有利于菌株生长及产酶的碳源、氮源物质;蔗糖、可溶性淀粉、麦芽糖及麸皮对CMCase的合成具有明显诱导作用;CMC、麸皮、可溶性淀粉及麦芽糖对滤纸酶的合成有一定诱导作用,单糖与部分双糖(蔗糖、纤维二糖及乳糖)则起阻遏作用;在指数生长后期至稳定早期,大量产CMCase;发酵液含CMCase、滤纸酶及葡萄糖苷酶活性,以CMCase活力最高;胞外CMCase活力占总CMCase活力的74．1％左右;酶最适作用温度35℃,5℃时酶活保留50％左右;酶对热敏感,35℃半衰期为3h,25℃下酶活稳定;酶最适pH8．0。     

异养硝化-好氧反硝化菌株DN1.2的脱氮特性研究

对一株具有异养硝化-好氧反硝化能力的恶臭假单胞菌Pseudomonas putida DN1.2进行了研究,初步探讨了不同碳源种类、碳氮比、pH值、温度、氨氮质量浓度对DN1.2菌株脱氮作用的影响.结果表明,该菌在异养硝化过程中能同时去除化学需氧量(COD)和氨氮,并且不积累硝酸盐和亚硝酸盐.碳氮比是影响其脱氮效果的重要因素.不同碳源种类下菌株的脱氮能力按大小排序为:乙酸盐＞葡萄糖＞柠檬酸盐＞甘油.脱除氨氮和COD的最适初始pH为7 0～7 5,最适温度为30～34℃.在菌株DN1 2转化的氨氮中有超过50%的部分被完全从水体中去除,细胞对氨氮的同化率为38 5%.     

产脂肪酶海洋嗜冷菌的鉴定及酶学性质研究

从东海的深海底泥中筛选出一株产脂肪酶的海洋细菌 EastSeaG5-1415,该菌为革兰氏阴性好氧菌,短杆状,0.9～1.3μm×1.5～3.8μm,无鞭毛,无芽孢,无色素,菌落光滑不透明,过氧化氢酶和氧化酶阳性,甲基红实验阴性,氧化葡萄糖产酸,可耐受10%的NaCl.此菌最适生长温度为18℃,最高生长温度为35℃,在0℃也能生长,是典型的嗜冷菌.菌株脂肪酸种类为C17:1(28.2%),C18:1 9c(49.7%),辅酶Q-8是其主要的异戊烯醌类,DNA中G C含量为45.2mol%.以16SrRNA同源性为基础构建了相关种属细菌在内的系统发育树,在系统发育树中,分离菌株 EastSeaG5-1415 与 Psychrobacter glacincola 在同一分支,二者的序列相似性为97.6%,DNA 杂交显示与 P.glacincola 最为相近,达到87%.结合形态和生理生化试验,将其鉴定为嗜冷杆菌 P.glacincola.同时对其所产脂肪酶的性质进行了初步研究.该菌所产碱性脂肪酶最适反应温度为35℃,在5℃时仍有较高酶活,酶活达到23%,最适 pH 值为9,属低温碱性脂肪酶.     

高效降解苯胺的菌株AD9的分离、生理生化特性分析和分子鉴定

从活性污泥中分离到一株能以苯胺为唯一碳源、氮源生长的苯胺降解菌株AD9,该菌株最适生长的苯胺浓度为1000mg／L,降解效率可达90％,对苯胺耐受程度高达4500mg/L,降解苯胺的最适pH值为7．0,最适温度为30℃。以上实验结果表明,AD9具有降解苯胺速率快、耐受苯胺浓度高的特性。该菌具有氨苄青霉素、卡那霉素和利福平抗性,无氯霉素、四环素抗性,其16SrDNA序列与多株Delftia sp．菌有很高的同源性,其G＋C含量为66．8mol％,非常接近于标准菌株D．tsuruhatensis T7（66．2mol％）。另外该菌和17的DNA-DNA杂交率为83．8％。结合AD9的表型鉴定将该菌株归属为D．tsuruhatensisas。这是D．tsuruhatensis菌种苯胺降解细菌菌株的首次报道。     

洋葱假单胞菌G63脂肪酶基因及其伴侣基因的克隆和同源高效表达

从油污土壤中筛选到一株脂肪酶活性较高的洋葱假单胞菌(Pseudomonas cepacia)G63.运用PCR的方法从该菌株中克隆了脂肪酶基因(lipA)及其伴侣基因(lipB).该脂肪酶基因开放式阅读框(ORF)为1092bp,编码364个氨基酸残基.经KpnⅠ/HindⅢ酶切,将其克隆到广泛宿主质粒pBBR1Tp载体上,构建成质粒pBBR1-lipAB.通过三亲杂交,在辅助质粒pRK2013的帮助下,转入原宿主菌P.cepacia G63中,构建成lipA基因同源高效表达的基因工程菌.该菌株在连续转接5次,培养45h后质粒保持率为82.6%,适用于规模化发酵生产.摇床发酵表明,工程菌在60h时酶活达到150.63 U/mL,较原始菌株提高3.6倍.     

假单胞菌phen8的降解特性及其缺失突变株的筛选

对分离筛选到的一株高效苯酚降解菌phen8（假单胞菌Pseudomonas sp.）的底物降解特性进行了分析,并筛选出四株缺的苯酚降解功能的突变株。结果表明,在苯酚初浓度为0－7mmol/L时,苯酚降解菌phen8的菌体密度和降率与培养基中的苯酚初浓度成正比,而大于7mmol/L的苯酚则明显地抑制降解反应,葡萄糖对苯酚的降解也表现出明显的抑制作用。与对照相比,在含有葡萄糖的基本培养基中培养20h后,菌体对苯酚的降解率减小47．2％。已筛选到的四个丢失苯酚降解功能的突变株,并今后降解基因的克隆和基因表达调控研究提供了良好的工作基础。     

南极嗜冷假单胞菌7197的分离和无机焦磷酸酯酶(PPase)基因ppa的克隆

从南极普利兹湾深海沉积物中筛选到一株耐冷菌株7197.16S rDNA序列分析表明,该菌株属于假单胞菌属(Pseudomonas).从该菌的全基因组DNA中克隆到编码无机焦磷酸酯酶(PPase)的ppa基因完整的开放阅读框(ORF),其全长为531bp.该基因编码一个由176AA残基组成的分子量预计为19631 Da的PPase蛋白质,其氨基酸序列与Psychrobacter sp.273-4的PPase有97%的相似性,与Neisseria meningitidis Z2491的PPase有79%的相似性,与Mannheimia succiniciproducens MBEL55E的PPase有75%的相似性.     

凝固科学技术与材料

从凝固科学与实践发展的角度介绍了当前凝固材料体系的基本框架和凝固科学主要发展阶段的基本理论。作为材料科学与工程的基本组成，凝固科学技术正在现代科学理论的基础上针对传统材料的改性提高和新材料的发展需求，以控形、控构、控性为目标开展优质铸件的定向、晶体生长、快凝、深过冷及各种新型和超常领域凝固过程的研究，并介绍了其中某些方面和展望了可能的发展趋势。     

The Candela and Photometric and Radiometric Measurements

The national measurement system for photometric and radiometric quantities is presently based upon techniques that make these quantities traceable to a high-accuracy cryogenic radiometer. The redefinition of the candela in 1979 provided the opportunity for national measurement laboratories to base their photometric measurements on optical detector technology rather than on the emission from high-temperature blackbody optical sources. The ensuing technical developments of the past 20 years, including the significant improvements in cryogenic radiometer performance, have provided the opportunity to place the fundamental maintenance of photometric quantities upon absolute detector based technology as was allowed by the 1979 redefinition. Additionally, the development of improved photodetectors has had a significant impact on the methodology in most of the radiometric measurement areas. This paper will review the status of the NIST implementation of the technical changes mandated by the 1979 redefinition of the candela and its effect upon the maintenance and dissemination of optical radiation measurements.     

PSD和PWELCH函数的分析改进及应用

针对MATLAB中两个内建功率谱密度计算函数psd()和pwelch()计算结果迥异的现象,在功率谱密度估计理论的基础上,根据经典的周期图理论和Welch平均周期图方法,通过详细分析源程序,解析计算方法,发现psd()计算的并不是工程单边功率谱密度,而是采样信号双边谱,故与pwelch()结果迥异,另外pwelch()不能对分段信号数据进行预处理。就上述不足提出了相应的改进措施,比较验证表明改进措施行之有效。     

江澳两地高校文创设计的协同研究与商业实践

目的 探索江门世遗文化的传承、发展和转化的新思路,践行国家在《粤港澳大湾区发展规划》纲要中要求江门承担与港澳地区文化创意合作与开发任务的分工。方法 与澳门高校紧密合作,开展专业培训课程,以开平碉楼为例,从人文视角开展设计研究,梳理开平碉楼的文化脉络,把世遗文化的元素和其背后的文化融入文创产品中,提升文创产品的附加值,推动当地文创产业结构的变革。结果 两地高校构建了稳定的科研团队,开设长期有效的设计培训课程,与景区建立了研究协作关系,帮助景区构建了一套产销研的商业模式。结论 以跨区域高校合作为平台,以文创产品为抓手,依托江澳两地的资源优势,可以构建江门世遗文化全新的品牌形象,最终推动开平世遗文化的活化。     

Creation and motion of dislocations and fracture in metal and silicon crystals

By making a step on one surface ( ) of a rectangular small paralellepiped copper crystal, dislocations could be created by the molecular dynamic method. The dislocation created was not a complete edge dislocation but a pair of Heidenreich-Shockley partial dislocations. Each time a dislocation was created, the stress on the surface was released. Small copper crystals having a notch were pulled (until fracture), compressed and buckled by use of the molecular dynamic method. An embedded atom potential was used to represent the interaction between atoms. Dislocations were created near the tip of the notch. A very sharp yield stress was observed. The results of high speed deformations of pure silicon small crystals using the molecular dynamics are presented. The results suggest that plastic deformation may be possible for the silicon with a high speed deformation even at room temperature. Another small size single crystal, the same size and the same surfaces, was compressed using molecular dynamic method. The surfaces are {110}, {112} and {111}. The compressed direction was [111]. It was found that silicon crystals are possible to be compressed with a high speed deformation. This may suggest that silicon may be plastically deformed with high speed deformation.     

Error and uncertainty in modeling and simulation

This article develops a general framework for identifying error and uncertainty in computational simulations that deal with the numerical solution of a set of partial differential equations (PDEs). A comprehensive, new view of the general phases of modeling and simulation is proposed, consisting of the following phases: conceptual modeling of the physical system, mathematical modeling of the conceptual model, discretization and algorithm selection for the mathematical model, computer programming of the discrete model, numerical solution of the computer program model, and representation of the numerical solution. Our view incorporates the modeling and simulation phases that are recognized in the systems engineering and operations research communities, but it adds phases that are specific to the numerical solution of PDEs. In each of these phases, general sources of uncertainty, both aleatory and epistemic, and error are identified. Our general framework is applicable to any numerical discretization procedure for solving ODEs or PDEs. To demonstrate this framework, we describe a system-level example: the flight of an unguided, rocket-boosted, aircraft-launched missile. This example is discussed in detail at each of the six phases of modeling and simulation. Two alternative models of the flight dynamics are considered, along with aleatory uncertainty of the initial mass of the missile and epistemic uncertainty in the thrust of the rocket motor. We also investigate the interaction of modeling uncertainties and numerical integration error in the solution of the ordinary differential equations for the flight dynamics.     

Miniature and MEMS-type vacuum sensors and pumps

In the paper, the observable trends of the actual research and development of selected types of miniature and MEMS-type vacuum sensors are presented. Some information about the new types of active vacuum gauges, which are offered by the leading manufacturers of the vacuum measurement instruments, is given. Next, the list of MEMS devices that need vacuum for proper operation is presented. Some aspects of vacuum-encapsulation of MEMS devices, on wafer level and package level are shown. The new conceptions of obtaining and maintenance of high and ultra-high vacuum in MEMS devices are described. They concern the conception of integration of a miniature orbitron pump on-chip with MEMS-type device or with vacuum part of the portable advanced instruments such as electron microscope, ion mass spectrometer, and free electron laser.