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71.
72.
硝胺推进剂用聚合物键合剂的研究进展 总被引:1,自引:0,他引:1
综述了硝胺推进剂产生"脱湿"现象的原因及改善力学性能的方法,介绍了目前国内外用于改善硝胺推进剂力学性能的三种聚合物键合剂的作用机理和效果。 相似文献
73.
Kavitej Samra Mathun Kuganesan William Smith Anna Kleyman Robert Tidswell Nishkantha Arulkumaran Mervyn Singer Alex Dyson 《International journal of molecular sciences》2021,22(6)
Metabolically active gasotransmitters (nitric oxide, carbon monoxide and hydrogen sulfide) are important signalling molecules that show therapeutic utility in oxidative pathologies. The reduced form of selenium, hydrogen selenide (HSe−/H2Se), shares some characteristics with these molecules. The simple selenide salt, sodium hydroselenide (NaHSe) showed significant metabolic activity, dose-dependently decreasing ex vivo O2 consumption (rat soleus muscle, liver) and transiently inhibiting mitochondrial cytochrome C oxidase (liver, heart). Pharmacological manipulation of selenoprotein expression in HepG2 human hepatocytes revealed that the oxidation status of selenium impacts on protein expression; reduced selenide (NaHSe) increased, whereas (oxidized) sodium selenite decreased the abundance of two ubiquitous selenoproteins. An inhibitor of endogenous sulfide production (DL-propargylglycine; PAG) also reduced selenoprotein expression; this was reversed by exogenous NaHSe, but not sodium hydrosulfide (NaHS). NaHSe also conferred cytoprotection against an oxidative challenge (H2O2), and this was associated with an increase in mitochondrial membrane potential. Anesthetized Wistar rats receiving intravenous NaHSe exhibited significant bradycardia, metabolic acidosis and hyperlactataemia. In summary, NaHSe modulates metabolism by inhibition of cytochrome C oxidase. Modification of selenoprotein expression revealed the importance of oxidation status of selenium therapies, with implications for current clinical practice. The utility of NaHSe as a research tool and putative therapeutic is discussed. 相似文献
74.
Bernhard Kienesberger Beate Obermüller Georg Singer Barbara Mittl Reingard Grabherr Sigrid Mayrhofer Stefan Heinl Vanessa Stadlbauer Angela Horvath Wolfram Miekisch Patricia Fuchs Ingeborg Klymiuk Holger Till Christoph Castellani 《International journal of molecular sciences》2021,22(12)
We aimed to assess the in vitro antimicrobial activity and the in vivo effect on the murine fecal microbiome and volatile organic compound (VOC) profile of (S)-reutericyclin. The antimicrobial activity of (S)-reutericyclin was tested against Clostridium difficile, Listeria monocytogenes, Escherichia coli, Enterococcus faecium, Staphylococcus aureus, Staphylococcus (S.) epidermidis, Streptococcus agalactiae, Pseudomonas aeruginosa and Propionibacterium acnes. Reutericyclin or water were gavage fed to male BALBc mice for 7 weeks. Thereafter stool samples underwent 16S based microbiome analysis and VOC analysis by gas chromatography mass spectrometry (GC-MS). (S)-reutericyclin inhibited growth of S. epidermidis only. Oral (S)-reutericyclin treatment caused a trend towards reduced alpha diversity. Beta diversity was significantly influenced by reutericyclin. Linear discriminant analysis Effect Size (LEfSe) analysis showed an increase of Streptococcus and Muribaculum as well as a decrease of butyrate producing Ruminoclostridium, Roseburia and Eubacterium in the reutericyclin group. VOC analysis revealed significant increases of pentane and heptane and decreases of 2,3-butanedione and 2-heptanone in reutericyclin animals. The antimicrobial activity of (S)-reutericyclin differs from reports of (R)-reutericyclin with inhibitory effects on a multitude of Gram-positive bacteria reported in the literature. In vivo (S)-reutericyclin treatment led to a microbiome shift towards dysbiosis and distinct alterations of the fecal VOC profile. 相似文献
75.
通过吹高纯氩气和水蒸汽混合气体的方法除去冶金级硅中的杂质磷。采用自行设计的吹气精炼装置,研究喷嘴类型、精炼时间、精炼温度、精炼气温度、精炼气流速等因素对除磷效果的影响。研究表明:使用侧壁和底部多孔型喷嘴,精炼时间3 h,精炼温度1793 K,精炼气温度373 K,精炼气流速2 L/min作为最优吹气精炼条件时,冶金级硅熔体中的磷元素质量分数由94×10-6降低到11×10-6。表明吹气精炼是一种有效的去除冶金级硅中磷的方法。 相似文献
76.
77.
Ostroverkhov V. Ostroverkhova O. Petschek R.G. Singer K.D. Sukhomlinova L. Twieg R.J. 《IEEE journal of selected topics in quantum electronics》2001,7(5):781-792
This paper describes the development and optimization of chiral, nonpolar media with large second-order nonlinear optical responses. We employ molecular engineering, quantum-mechanical sum-over-states theory, and measurements of molecular hyperpolarizability by means of Kleinman-disallowed hyper-Rayleigh scattering in order to understand molecular properties. Then we analyze the appropriate arrangement of the chromophores that produce an optimum axial nonlinear optical medium. Chromophores with large Kleinman disallowed traceless symmetric second-rank tensor hyperpolarizabilities β can be aligned so as to result in large susceptibilities χ(2) in structures that lack polar order. We found that Λ-shaped chromophores with C2v or similar symmetry are good candidates for these materials, as they can exhibit large second-rank components of the hyperpolarizability tensor. A wide variety of techniques can be used to fabricate bulk materials belonging to the chiral nonpolar symmetry groups D∞ and D2. The microscopic chromophore alignment schemes that optimize the nonlinear optical response in such materials are deduced from general symmetry consideration for both molecules and bulk. We also speculate on the possible application of such materials as high-bandwidth spatial light modulators 相似文献
78.
79.
Peter Singer 《集成电路应用》2006,(6):14-14
Intel采用45nm工艺技术制作了该行业第一块全功能SRAM芯片,目标是于2007年采用该技术在300mm晶圆上开始制造芯片。目前Intel在Arizona和Oregon有两个制造厂制造65nm芯片,今年在Ireland和Oregon将有两个以上新厂投入生产。 相似文献
80.
Peter Singer 《集成电路应用》2006,(6):13-13
NEC Corp.日前宣布已成功地开发出基础硅纳米光电技术,消除了数据传输的瓶颈从而推动了光数据在大规模集成(LSI)芯片中的传输。此项研究是在今年年初举行的国际固态电路会议(ISSCC)上提出来的。 相似文献