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221.
A new basic electrolyte with two cationic plating additives,polydiaminourea and polyaminosulfone,was investigated for the electrochemical deposition of the bismuth telluride film on a nickel-plated copper foil.Tellurium starts to deposit at a higher potential(-0.35 V) than bismuth(-0.5 V) in this electrolyte.The tellurium-to-bismuth ratio increases while the deposition potential declines from-1 to-1.25 V, indicating a kinetically quicker bismuth deposition at higher potentials.The as-deposited film featu... 相似文献
222.
提高高校图书馆的管理效益和水平,必须使高校图书馆的管理观念从科学管理转为信息资源管理;管理模式的体制、结构、服务内容、操作以及人员知识结构必须适当改变,以适应信息资源的要求。 相似文献
223.
Twelve samples derived from different locations in south central area of China are treated by enrichment and spread-plate
technique for initial screening. Seven chitinase-producing strains are isolated. The chitinase present in the culture supernatant
of strain CS-01 possesses the maximum activity of 0.118 U/mL. Analysis of the morphological feature and the ITS rDNA sequence
reveals that strain CS-01 belongs to Aspergillus fumigatus. Production of the chitinase is regulated by a inducible way and the maximum activity appears at 36 h in colloidal chitin
culture. Purification of the chitinase is carried out by salting out, gel filtrate chromatography and anion exchange chromatography
sequentially. Native-PAGE and SDS-PAGE indicate that the chitinase from A. fumigatus CS-01 is a monomer with the relative molecular mass estimated to be 4.50×104. Its maximum activity appears at pH 5 and 55 °C. The chitinase is stable at pH 4.0–7.5 and below 45 °C.
Foundation item: Projects(50621063, 50674101) supported by the National Natural Science Foundation of China 相似文献
224.
Di-n-butyl phthalate (DBP), one of phthalate acid esters (PAEs), was investigated to determine its biodegradation rate using Xiangjiang
River sediment and find potential DBP degraders in the enrichment culture of the sediment. The sediment sample was incubated
with an initial concentration of DBP of 100 mg/L for 5 d. The biodegradation rate of DBP was detected using HPLC and the degraded
products were analyzed by GC/MS. Subsequently, the microbial diversity of the enrichment culture was analyzed by polymerase
chain reaction-restriction fragment length polymorphism (PCR-RFLP). The results reveal that almost 100% of DBP is degraded
after merely 3 d, generating two main degraded products: mono-butyl phthalate (MBP) and 9-octadecenoic acid. After a six-month
enrichment period under the pressure of DBP, the dominant family in the final enrichment culture is clustered with the Comamonas sp., the remaining are affiliated with Sphingomonas sp., Hydrogenophaga sp., Rhizobium sp., and Acidovorax sp. The results show the potential of these bacteria to be used in the bioremediation of DBP in the environment. 相似文献
225.
Mixed microorganisms with elevated activity of chalcocite-leaching were screened by mutation methods. The original microorganisms
collected from acid mine drainage of different sites were mixed and then treated with mutagens NO2−, diethyl sulfate (DES), UV and their combinations, respectively. Five groups of mixed microorganisms with much stronger ore-leaching
ability were obtained by screening on the leaching media. Among them, group E of mixed microorganisms (treated with 1% DES
for 60 min) with the best performance on chalcocite-leaching, increases the content of Cu2+ by 101.4% in 20 d of leaching compared with the control culture. In addition, group E is more tolerant to Cu2+ in media than the control without mutation treatment. Analysis for the diversity of microbial clones indicates that half
of operational taxonomic units (OTUs) in group E are Acidithiobacillus ferrooxidans. These observations suggest that group E might have potentials for industrial application.
Foundation item: Project(50321402) supported by the National Natural Science Foundation of China; Project(2004CB619201) supported by the Major
State Basic Research and Development Program of China 相似文献
226.
Identification and fermentation optimization of protopectinase-overproducing strain Aspergillus niger CD-01 for pectin production 总被引:1,自引:1,他引:0
In order to solve the citrus peel resource waste problem and minimize the drawbacks of chemical extraction of pectin, a protopectinase-overproducing
strain CD-01 for pectin production was isolated from a pit soil dumped with perished orange in Changde City, Hunan Province
of China. The strain CD-01 had the same morphology and 28S rRNA gene sequence (FJ184995) as that of Aspergillus niger (ATCC 64028). It was thus identified and named as Aspergillus niger CD-01. The fermentation condition was optimized based on L9(34) orthogonal experimental design and the variances analyses. The results show that the optimal condition for producing pectin
is as follows: time 36 h, temperature 35 °C, pH 5, and urea as the nitrogen source. Under this condition, the pectin yield
can reach up to 24.5%. This shows a great potential of Aspergillus niger CD-01 in pectin extraction from citrus.
Foundation item: Projects(50621063, 50674101) supported by the National Natural Science Foundation of China 相似文献
227.
228.
<伤逝>围绕着理想与绝望这一人生核心问题,通过涓生与子君人生理想终极悖论的层层设置,不断突围和最终否定,阐释出无论是人生理想、反抗,还是绝望,都应清醒地把握当时的社会现状与自我的人生状况.文本准确地剖析了当时的社会与人生,把人生哲理和当时社会现实紧紧结合在一起,让读者透过时代脉搏的律动,感受人生的真谛. 相似文献
229.
基于频率选择性衰落信道,改进了以一般多径信道为模型的传统MLSE算法,提出了将分集接收方法与MLSE算法联合的改进MLSE算法;通过建立与分析新算法模型,推导得到新的误码率性能上界;对一般多径条件下的传统MLSE和在频率选择性衰落信道条件下新算法的误码率性能及性能界进行了仿真.仿真结果表明,使用分集接收的新算法性能界与... 相似文献
230.
外涵装有脉冲爆震加力燃烧室的涡扇发动机热力性能分析 总被引:1,自引:0,他引:1
在传统涡扇发动机外涵安装12个内径68 mm的脉冲爆震燃烧室(PDCs)作为加力燃烧室,排气方式有2种,即分别排气和混合排气,建立了相应的热力性能分析模型,应用所建立的模型,计算了不同飞行状态下的性能。计算结果表明:在设计点条件下,与分别排气涡扇发动机相比,外涵装有PDCs的分别排气涡扇发动机模型(PS模型)的单位推力(Fs)提高127.6%,混合排气发动机模型(PM模型)的Fs提高74.6%,单位燃油消耗率(sfc)较传统带加力的涡扇发动机低。飞行高度一定随着飞行马赫数的增加,脉冲爆震外涵加力涡扇发动机Fs减小,sfc增加;飞行马赫数一定随着飞行高度的增加,PS模型的Fs减小,sfc增加,而PM模型的Fs缓慢增加,sfc缓慢减小。飞行马赫数、飞行高度均较低时,PS模型的工作性能显示了明显的优越性,而PM模型可以在很宽的工作范围内保持优越且稳定的工作性能。 相似文献