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971.
972.
WANGSen-lin WUHui-huang 《高等学校化学研究》2005,21(3):315-321
The autocatalytic deposition of Ni-Zn(Fe)-P alloys has been carried out on substrate of carbon steel from a bath containing nickel sulfate, zinc sulfate, sodium hypophosphite, sodium citrate and boric acid. The effects of pH and the molar ratio of NiSO4/ZnSO4 on the deposition rate and the composition of deposits have been studied. It was found that the presence of zinc sulfate in the bath has an inhibitory effect on the alloy deposition. The structure and the surface morphology of Ni-Zn(Fe)-P coatings were characterized with XRD and SEM, respectively. The alloys plated under the experimental conditions consisted of an amorphous phase coexisting with a crystalline cubic Ni phase (poly-crystalline). The surface morphology of the coating is dependent on the deposition parameters. The corrosion resistance of the Ni-Zn(Fe)-P deposits was examined via mass loss tests and anodic polarization measurements, respectively. The results show that the surface morphologies of the deposits and the corrosion resistance of the deposits have been improved. The results of mass loss tests almost accord with those of anodic polarization measurements. The corrosion mechanisms of Ni-Zn(Fe)-P alloys in NaCl and NaOH solutions were investigated by means of EDX. The deposit immersed in an NaCI or an NaOH solution contains more content of oxygen and less contents of the metals(except Fe) than that placed in air, which shows that the NaCl or NaOH solution can accelerate the oxidation of the deposit. 相似文献
973.
WU Yin MENG Xiang-ying LIU Xiao-hua BAO Yong-li WANG Shu-ping LI Yu-xin 《高等学校化学研究》2005,21(6):658-662
The essential oils of the flower-buds, leaves and stems of Filipendula palmata( Pall. ) Maxim. were analyzed by GC and GC-MS. Thirty-three, forty-seven and forty-seven compounds in the flower-buds, leaves and stems were identified, respectively. Methyl salicylate exists in a great amount which is up to 70. 10% in the flower-buds. Its amount is also high in other two parts. The data obtained show that it may be one of the main natural mosquito-expelling and pain-alleviating components in the three parts. The flower-buds are the main active part with the mosquito-expelling function. 相似文献
974.
FU Ping-ping+{ } WANG Xin-long+ WANG En-bo~** QIN Chao+ XU Lin+. Institute of Polyoxometalate Chemistry Department of Chemistry Northeast Normal University Changchun P. R. China . China-Japan Union Hospital Jilin University Changchun P. R. ChinaReceived Dec. 《高等学校化学研究》2005,21(5):509-511
Introduction Over the past decades, polyoxometalates(POMs)have been attracting extensive interestowing to the widerange of their topological properties and potential appli-cations in catalysis, photochemistry, electrochromism,and magnetism[1,2]. Meanwhile, owing to the potentialapplication of polyoxometalaes as anticancer and antivi-ral drugs, their complexes have attracted increasing in-terest of both inorganic chemists and biochemists[3]. Itis well known that polyoxometalates are excellent … 相似文献
975.
AI Chun-Zhi SUN Ren-An② YAN Jie 《结构化学》2005,24(12):1445-1451
1 INTRODUCTION transfer species with common formula H-Rgδ -Xδ, where X represents a strongly electrone-gative atom Since xenon hexafluoraplatinate, XePtF6 , the [1] or fragment, and Rg is a rare-gas atom. These species first rare gas-containing compound was discovered have linear equi- librium geometries and are mainly by Bartlett in 1962, rare gases are getting more and bound up by strong columbic attraction between (H- more attention and have been found to be possible to Rg) and… 相似文献
976.
GENG Zhi-Yuana② WANG Dong-Meia c WANG Yong-Chenga DAI Guo-Lianga LU Ling-Linga WANG Han-Qingb a 《结构化学》2005,24(11):1334-1339
1 INTRODUCTION In experiment, it is difficult to reveal the pheno- menon that molecules decompose into several frag- ments by UV light mainly due to the insufficient en- ergy of illuminating source. But in oxalyl halides, their bond energies are relatively lower. As a typical system for the study of multi-channel dissociation, oxalyl chloride can be dissociated into four frag- ments: Cl˙, Cl˙, CO and CO, under proper UV light[1, 2], which is the chief way to obtain free radi- cals. … 相似文献
977.
针对超薄导光板微结构模具难加工的问题,结合等温热压印法,提出了一种新型的"等效替代"压印工艺,即通过控制成型工艺参数来降低微结构复制高度,实现了在基片上成型出小于模具微结构尺寸的等效结构,突破了热压印过程中模具微结构完全等大复制的思想禁锢,降低了微结构模具加工难度,从而革新了高质量超薄导光板的成型工艺。以聚甲基丙烯酸甲酯(PMMA)为基片,设计具体实验,加工0.25 mm厚的导光板,验证这一方法的可行性。实验结果表明,这种新型的"等效替代"压印工艺不仅可以降低模具的制造难度和加工成本,而且可以大大改善超薄导光板的性能,与等温热压印工艺相比均匀度提高了23%,整个成型时间缩短到了20 s。 相似文献
978.
979.
980.
螺纹加工方法最常见的是数控车削加工.探讨数控车削加工时根据不同的加工精度、不同的加工材料,分别选取不同的编程指令、不同的工件装夹方式、不同的加工刀具、不同的切削参数等,在实际螺纹数控车削加工中的合理性.探析螺纹数控加工的特殊性,探索如何实现精确控制螺纹数控车削加工,以及在实际加工中生产出高效、高精、稳定可靠的螺纹产品. 相似文献