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991.
992.
研究用于Ni-P/Al2O3化学复合镀液的Al2O3悬浮液分散剂.将140 nm的α-Al2O3干粉与表面活性剂溶液混合,采用高速机械搅拌和超声波分散Al2O3悬浮液.通过分光光度计测定悬浮液吸光度,用PdCl2测试镀液稳定性;通过孔隙率试验和结合力试验测试化学复合镀层性能,用SEM和EDS测试镀层形貌和化学成分.试验结果表明,阴离子型表面活性剂与非离子型表面活性剂复配,对Al2O3悬浮液的分散稳定有较好的协同效果,适宜的复配分散剂组成为:20 mg/L十二烷基硫酸钠,150 mg/L Tween-80,80 mg/L聚乙二醇.用其配置2 g/L纳米Al2O3悬浮液,静置24 h后吸光度为1.595.该悬浮液配置的镀液稳定性试验时间为165 s,镀速为16.5μm/h.复合镀层中Al2O3粒子呈弥散状分布,Al2O3含量为0.77%.镀层光亮、致密.孔隙率为0.06个/cm2.结合力符合GB/T13913-92标准.该复配分散剂适应于Ni-P/Al2O3化学复合镀液. 相似文献
993.
以有机物前驱体法制备铝酸盐尖晶石MAl2O4(M为Cu,Zn),采用X-射线衍射、透射电镜等方法对试样进行表征.结果表明:700℃焙烧得ZnAl2O4,800℃焙烧得到CuAlz04和微量Cu0.在以甲基橙为降解物和100W汞灯辐照2h的光催化实验中,700℃焙烧ZnAl2O4粉体对甲基橙的脱色率为89.4%;而800℃的CuAl2O4对甲基橙的脱色率可以达到96.7%. 相似文献
994.
TiSiW_(12)O_(40)/TiO_2的合成、表征及催化性能研究 总被引:4,自引:0,他引:4
本文报道了非均相固载型杂多酸盐催化剂TiSiW12O40/TiO2的制备方法,并用IR、XRD谱对该催化剂进行了表征,研究了该催化剂催化酯化合成邻苯二甲酸二丁的醇酸比、催化剂用量、带水剂等因素对酯收率的影响。实验表明,在以苯为带水剂时,催化剂的用量为反应液的1.1%,醇酸摩尔比为3.5∶1,酯化反应时间为2.5h,邻苯二甲酸二丁酯的收率达98.8%,超过硫酸、磷钨酸的催化水平 相似文献
995.
996.
On estimating a knowledge production function at the firm and sector level using patent statistics 总被引:1,自引:0,他引:1
This paper proposes a definition of the knowledge base of an agent using only patent statistics. It then develops a model of a knowledge production function that can be estimated at the firm level and the sector level using the knowledge base matrix. It identifies the impact of own knowledge base, absorptive capacity to exploit intersectoral spillovers, and absorptive capacity to exploit intrasectoral spillovers, on new technology generation. It permits a study of the dynamics of knowledge generation without having to resort to additional information on the R&D activities of firms. Finally, the paper illustrates the method with the case study of new biotechnology-based knowledge creation by firms in the foods sector. 相似文献
997.
This paper provides an empirical investigation of the national determinants of outbound international patenting, particularly focusing on the roles of trade-related influences and the destination countries’ strength of intellectual property protection. Based on cross-patenting from 30 member countries in the World Intellectual Property Organization (WIPO) between 1995 and 1998, empirical results suggest that the behavior of outbound international patenting is strongly and positively associated with trade-related influences, like exports and outward foreign direct investments. Moreover, controlling for other variables, a country with stronger protection of intellectual property rights (IPR) tends to force more foreign inventors to file for patent applications, lending a supportive view of cross-country evidence for the strong-IPR hypothesis. 相似文献
998.
This paper explores what factors determine the nature, extent, and location of Japanese multinationals’ R&D activities abroad. Taking advantage of a rich micro-level dataset from the survey on Japanese overseas subsidiaries, the study distinguishes between two types of overseas R&D: basic/applied research and development/design. We find several differences between the determinants of those R&D activities. These differences confirm the view that basic/applied research of overseas subsidiaries aims at the exploitation of foreign advanced knowledge, whereas their development/design activities are mostly influenced by the market size of the host country. Our results provide a convincing and comprehensive explanation of the geographical distribution of overseas R&D by Japanese MNEs. 相似文献
999.
This paper investigates domestic and foreign innovating firms’ determinants of R&D collaboration with domestic universities and public knowledge institutes in Finland and the Netherlands. We put particular emphasis on the impact of incoming academic spillovers on the probability to co-operate with these public R&D institutes.Based on data from Community Innovation Surveys we find that foreign firms in the Netherlands are less likely to co-operate with domestic public knowledge institutions than domestic firms, while in Finland no significant difference can be detected. Another result is that incoming knowledge spillovers are an important determinant for R&D collaboration with domestic public knowledge institutions in both countries. In case of foreign firms in Finland, incoming knowledge spillovers affect the probability to co-operate with public knowledge institutions more positively compared to domestic firms. For the Netherlands no substantial difference could be found in this respect. Further, innovating firms in Finland that require academic or basic knowledge do not co-operate significantly more with public knowledge institutions than those that need applied knowledge. At the same time they are willing to share knowledge with public R&D partners. In the Netherlands innovating firms that require relatively more basic than applied knowledge, increase the probability of co-operation with Dutch universities and public knowledge institutions but there is reluctance to share proprietary knowledge with public R&D partners. For both countries no significant difference between foreign and domestic firms with regard to academic knowledge requirements could be found. This raises the issue whether Finnish innovation policies with a strong focus on R&D co-operation provide incentives for strategic behaviour by domestic public partners to put more emphasis on applied research. 相似文献
1000.
目的:构建真核表达IL-18-GPI融合基因的表达载体,观察融合蛋白在哺乳动物细胞中的表达动力学及生物学活性,为进一步研究细胞因子作为免疫增强剂在临床肿瘤治疗中的应用奠定基础.方法:通过RT-PCR的方法从脂多糖刺激的外周血淋巴细胞中钓取IL-18基因,通过共用限制性酶切位点与GPI相连形成pcDNA-IL-18-GPI真核表达质粒.将质粒转染CHO细胞后建立稳定表达融合蛋白的细胞株用于融合蛋白的提取.对提取纯化的蛋白进行生物学特性、蛋白质转移分析和γ-IFN诱导实验.结果:获得714 bp的核酸序列并构建重组质粒pcDNA-IL-18-GPI.SDS-PAGE和West-blot显示在CHO细胞中表达的IL-18-GPI融合蛋白分子量约为27.5 kD,该蛋白具有明显的蛋白转移和诱生γ-IFN的作用.结论:IL-18-GPI融合蛋白是一种潜在的肿瘤疫苗增强剂,具有良好的应用前景. 相似文献