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21.
稀土变质ZA43合金的研究   总被引:1,自引:0,他引:1  
为改善和提高高铝锌合金(ZA43)的力学性能和耐磨性,采用Ce基混合稀土对ZA43合金进行了变质处理,系统研究和探讨了稀土对ZA43合金的力学性能和耐磨损性能的影响规律.研究结果表明:稀土的加入能够显著细化ZA43合金的铸态组织,减小化学成分偏析.随着稀土含量的增加,合金的力学性能和耐磨性得到不同程度的改善,当稀土含量...  相似文献   
22.
Photosystem Ⅱ (PS Ⅱ ) is a pigment-protein com-plex that catalyses the primary photochemistry leading to oxygen evolution and electron flow in oxygenic phototrophs. The reaction center of PSⅡ is composed of the D1 and D2 proteins to which all the redox…  相似文献   
23.
叶面喷施亚硒酸钠对盆栽茶叶硒含量的影响研究   总被引:1,自引:0,他引:1  
研究了叶面喷施亚硒酸钠对盆栽龙井43和白茶中硒含量的影响。实验结果表明,叶面喷施亚硒酸钠能明显提高茶叶含硒量,提高幅度跟亚硒酸钠的喷施浓度有关,当硒肥浓度为240μg Se/mL时,龙井43在春季可到最高的445μg/kg,夏季白茶中硒含量最高可达486μg/kg,都能达到富硒茶的标准;硒含量的变化也跟采摘时间和茶叶品种密切相关,因此利用叶面喷施硒肥在低硒地区生产富硒茶具有一定的可行性。  相似文献   
24.
JAVA网络通信机制的研究   总被引:3,自引:0,他引:3  
从使用URL类访问WWW资源和使用套接字(Socker)进行网络通信两方面论述Java的网络通信机制,并给出了应用实例。  相似文献   
25.
Nerve regeneration factor (NRF) extracted from an oral liquid of traditional Chinese medicine, as a nerve growth decoction has been reported by previous studies to exert effects of promoting nerve growth and preventing neuron apoptosis. For new insights into the function of NRF on primary cultured neurons, we investigated the neurite outgrowth in cultured rat dorsal root ganglion (DRG) explant treated with NRF by immunofluorescence and the gene and protein expressions of neurofilament-H(NF-H) and growth associated protein 43 (GAP43) in the cultured rat DRG neurons by real-time quantitative RT-PCR and Western blotting, respectively. In addition, we used a rat model of sciatic nerve crush to evaluate the effect of NRF on regeneration of injured sciatic nerve by a combination of walk track analysis, electrophysiological and histological assessments. The in vitro experiments indicated that NRF promoted the neurite growth of DRGs and the expression of NF-H and GAP43 at mRNA and protein levels in DRG neurons, and in vivo experiments showed that NRF improved peripheral nerve regeneration and functional recovery.  相似文献   
26.
将菠菜43 kD叶绿素结合蛋白编码基因亚克隆至原核表达载体pET-28a上,构建重组表达质粒pET-28a-psbC转化感受态E.coli BL21(DE3),经IPTG诱导实现了外源基因的可溶性表达.探讨了含组氨酸标签融合蛋白的最佳表达条件(包括表达单克隆、时间、温度对表达的影响).利用Ni2+-Sepharose 4 Fast Flow亲合层析纯化出His-apo CP43蛋白.体外重组实验证实 His-apo CP43能特异结合叶绿素a,经过温和电泳分离纯化所得体外重组色素蛋白复合物具有与提取自类囊体膜的天然CP43相似(但不完全相同)的荧光特性.  相似文献   
27.
A Ni47Ti43Hf10 high temperature shape memory alloy is fabricated. The martensitic transformation temperature (TT) is obtained by differential scanning calorimetry and four-probe electrical resistivity measurements. The effect of thermal cycling is investigated and it is found that the TT tends to be stable quickly, which is of benefit to practical applications. The martensite structure is determined to be B19′ monoclinic by X-ray diffraction and transmission electron microscopy. One-way and two-way (which is seldom reported before) shape memory properties are studied by tensile and bending tests. The cycling number of two-way shape memory effect is tested for more than 20000 times.  相似文献   
28.
Objective: To assess the effect of angiotensin II type 1 (AT1) receptor antagonist losartan on myocardium connexin43 (Cx43) gap junction (GJ) expression in spontaneously hypertensive rats (SHRs) and investigate possible mechanisms. Methods: Sixteen 9-week-old male SHRs and 8 age-matched male Wistar-Kyoto (WKY) rats were included in this study. SHRs were randomly divided into two groups to receive losartan at 30 mg/(kg·d) by oral gavage once daily for 8 weeks (SHR-L) or vehicle (0.9% saline) to act as controls (SHR-V); WKY rats receiving vehicle for 8 weeks served as normotensive controls. At the end of the experiment, rats were sacrificed and the hearts were removed. Expressions of Cx43 and nuclear factor-kappaB p65 (NF-κB p65) proteins in all three groups were observed and further investigations on the effect of angiotensin II type 1 receptor antagonist losartan (30 mg/(kg·d), 8 weeks) on Cx43 expression were conducted with Western blot and immunohistochemistry. NF-κB p65 protein in nuclear extracts was determined by Western blot. Results: Left ventricular (LV) hypertrophy was prominent in SHRs, Cx43 and NF-κB p65 protein expressions were obviously upregulated and Cx43 distribution was dispersed over the cell surface. Treatment with losarton reduced the over-expressions of Cx43 and NF-κB p65 in LV myocardium. The distribution of Cx43 gap junction also became much regular and confined to intercalated disk after losartan treatment. Conclusion: Cx43 level was upregulated in LV myocardium of SHR during early stage of hypertrophy. Angiotensin II type 1 receptor antagonist losartan prevented Cx43 gap junction remodeling in hypertrophied left ventricles, possibly through the NF-κB pathway.  相似文献   
29.
We have prepared an aqueous extract of Achyranthes bidentata Blume, a commonly prescribed Chinese medicinal herb, and reported, in previous studies, that A. bidentata extract benefits nerve growth and prevents neuron apoptosis. In this study, we investigated the actions of A. bidentata extract on survival and growth of primarily cultured rat hippocampal neurons. The morphological observation revealed that neurite growth from hippocampal neurons was significantly enhanced by A. bidentata extract with similar effects to those induced by nerve growth factor (NGF), and the greatest neurite growth appeared on treatment with A. bidentata extract at 1 μg/ml for 24 h. DNA microarray analysis indicated that there were 25 upregulated genes and 47 downregulated genes exhibiting significantly differential expression in hippocampal neurons treated with A. bidentata extract at 1 μg/ml for 6 h when compared to those in untreated hippocampal neurons. Real-time quantitative RT-PCR and Western blot analysis demonstrated that the expression of growth-associated protein-43 in hippocampal neurons was upregulated at both mRNA and protein levels after treatment with A. bidentata extract, and the optimal dosage of the extract was also 1 μg/ml. These data confirm that A. bidentata extract could promote in vitro hippocampal neuronal growth in a dose- and time-dependent manner.  相似文献   
30.
采用原位接触反应法制备了TiC/ZA43复合材料,并对其在干摩擦和预先滴油润滑条件下的摩擦摩损性能进行了试验研究,同时还用扫描电子显微镜对试样磨损表面形貌进行了观察,进而对材料的磨损机理作为分析与讨论,结果表明,随着TiC质量分数的增大,TiC/ZA43复合材料的耐磨性能提高,ZA43合金的磨损机理是以严重的犁削和磨损为主,而TiC/ZA43复各材料的磨损机理则以轻微的犁削和氧化磨损为主。  相似文献   
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