激光-等离子体相互作用过程中光子加速的研究

为了研究激光-等离子体相互作用过程中的光子加速(光子频率上移),采用数值模拟方法进行了理论计算和数值计算验证,取得了光子加速的重要计算机模拟结果。结果表明,等离子体激光相互作用过程中的光子频率上移与所用的激光脉冲形式和脉冲宽度有关,存在最佳脉冲宽度和脉冲上升宽度,还存在等离子体电子密度上限。这一结果对进一步研究激光等离子体粒子加速有帮助。     

Enhanced conductivity of SDC based nanocomposite electrolyte by spark plasma sintering

Recently, ceria-based nanocomposites have been considered as promising electrolyte candidates for low-temperature solid oxide fuel cells (LTSOFC) due to their dual-ion conduction and excellent performance. However, the densification of these composites remains a great concern since the relative low density of the composite electrolyte is suspected to deteriorate the durability of fuel cell. In the present study, the ionic conductivity of two kinds of SDC-based nanocomposite electrolytes processed by spark plasma sintering (SPS) method was investigated, and compared to that made by conventional cold pressing followed by sintering (normal processing way). The density of solid electrolyte can reach higher than 95% of the theoretical value after SPS processing, while the relative density of the electrolyte pellets by normal processing way can hardly approach 75%. The structure and morphology of the sintered pellets were characterized by XRD and SEM. The ionic conductivity of samples was measured by electrochemical impedance spectroscopy (EIS). The results showed that the ionic conductivity of the two kinds of electrolytes treated with SPS was significantly enhanced, compared with the electrolyte pellets processed through the conventional method. The profile of impedance curve of the electrolytes was altered as well. This study demonstrates that the conductivity of SDC based nanocomposite electrolyte can be further improved by adequate densification process.     

运算放大器不同剂量率的辐射损伤效应

对几种不同类型(TTL,CMOS,JFET-Bi,MOS-Bi)的典型星用运算放大器在不同剂量率(100,10,1及0.01rad(Si)/s)辐照下的响应规律及随时间变化的退火特性进行了研究.结果显示不同类型运放电路的辐照响应有明显差异:双极运放电路辐照剂量率越小,其损伤越大;CMOS运放电路对不同剂量率的响应并非线性关系,但不同剂量率辐照损伤的差异,可以通过与低剂量率相同时间的室温退火得到消除,本质上仍然是与时间相关的效应;JFET输入运放不仅有低剂量率辐照损伤增强效应存在,且辐照后还有明显的"后损伤"现象;PMOS输入运放的结果则表明,各辐照剂量率间的损伤无明显区别.     

碱性果胶酶产生菌Bacillus claussi XJU-8的分离鉴定及酶学特性分析

从新疆石河子市一处工业污水(pH11.0)中分离到一株碱性果胶酶产生菌,编号XJU-8。应用形态学检测、生理生化实验、16S rDNA序列分析、系统进化分析对菌株进行多相鉴定。XJU-8可在pH5.0～13.0的LB培养基上生长,最适生长温度37℃。16S rDNA序列构建的系统进化树表明XJU-8与Bacillus claussi类聚在一起,而且序列同源性高达99%以上。XJU-8与B.claussi GMBAE 42在氧化酶,柠檬酸盐利用和水解Tween-40、Tween-60上有差异,且XJU-8有宽范围pH值耐受性,被认为是B.claussi的一个新品系。该菌产生的碱性果胶酶最适pH10.0,最适温度50℃,在pH9.0～12.0有较高活性和稳定性。酶活性可被Ca2+盐激活。XJU-8所产碱性果胶酶特性良好,工业应用潜能巨大。     

Subcritical state diagnosis for nuclear power plant containing RBMK-1000

Leningrad Reactor Research Institute. Translated from Atomnaya Énergiya, Vol. 70, No. 3, pp. 180–182, March, 1991.     

Keratitis complicated by endophthalmitis 3 years after astigmatic keratotomy

Endophthalmitis after keratotomy is rare and usually occurs soon after surgery. A 56-year-old woman with mild dry-eye symptoms developed keratitis complicated by endophthalmitis 3 years after astigmatic keratotomy (AK). The keratitis lasted for less than 1 day in the upper keratotomy incision. Corneal cultures yielded. Pseudomonas aeruginosa. Keratitis progressed to endophthalmitis 1 day after the detection of keratitis. The inflammation was controlled with intravitreal, subconjunctival, topical, and systemic antibiotics. This case demonstrates the potential risk of endophthalmitis developing very shortly after late keratitis of AK incisions. Vigorous early treatment and close follow-up seem justifiable in any keratitis associated with a keratotomy incision.     

Making Bibelot: Casting material research within cultural frameworks

Material investigations in architecture often exclude practice implications by narrowly determining the scope and limitations of research. Such limitations are necessary and warranted for open-ended inquiries undertaken in controlled conditions. Working with commercial outfits in the context of a prescribed project, on the other hand, requires a clear attitude that accounts for the agency of the manufacturer. A small design-build intervention, completed with an in-kind donation from a terra cotta manufacturer in Buffalo, New York, gave us the opportunity to take on such a collaborative investigation. In order to explore the potentials of terra cotta as a building material to the greatest extent, we strategically increased the complexity of the endeavor, challenging the design and manufacturing team to address production problems in a timely manner to meet the project goals. In doing this, we relied on conceptual constructs that address specific material and institutional histories of terra cotta and the cultural context, registered as form, color, and ornamentation in the project. The paper gives a detailed account of the entire process and the working assumptions by bridging the design and manufacturing decisions in an interrelated manner.