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排序方式: 共有69条查询结果,搜索用时 15 毫秒
1.
硫化法与磁场协同处理含砷废水的研究 总被引:4,自引:0,他引:4
采用硫化法与磁场协同处理含砷废水,提高了硫化渣的絮凝沉降速度和过滤速度,并提高了硫化剂的利用率。经磁场处理后,溶液的电导率增加,电势降低,机理分析表明,磁化处理使水的结构发生了变化,改善了水的渗透效果。 相似文献
2.
Rengang Zhang Baoyi WangLong Wei Xin LiQianshan Xu Shunjin PengIbrahim Kurash Haijie Qian 《Vacuum》2012,86(8):1210-1214
ZnS thin films with the hexagonal structure have been produced by sulfurizing sputter deposited Zn in sulfur vapor for 1 h. These films have been analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), synchrotron radiation photoelectron spectroscopy (SR-PES), Auger electron spectroscopy (AES) and UV-VIS transmission spectra. It is found that at the sulfidation temperature (TS) of 400 °C a little and partial Zn can be transformed to ZnS. At TS = 500 °C, the total conversion of Zn in sulfur vapor can take place and form ZnS with a c-axis preferred orientation. The Zn-to-ZnS conversion is kinetically a reactive diffusion process. Also the ZnS thin film has much greater size of grains than the as-deposited Zn film, due to ZnS recrystallization and growth in sulfur vapor. Residual sulfur existing on the surface of ZnS grains leads to the poor optical transparency and great broadening of absorbing edge in the optical transmittance. However, ZnS thin film prepared by gradient sulfidation exhibits the improved optical transmittance, with a band-gap energy of 3.64 eV. 相似文献
3.
以板状刚玉(6 mm~1 mm、1 mm~0.5 mm、0.5 mm~0mm)、烧结尖晶石颗粒(1mm~0.5 mm)为骨料,电熔尖晶石细粉(≤0.044 mm)、白刚玉细粉(≤0.044 mm)、α- Al2O3微粉(≤5μm,d50=2.01 μm)、纯铝酸钙水泥为基质,按骨料与基质的质量比为70∶30配料,以烧结... 相似文献
4.
Tri-arc双丝电弧焊堆焊工艺研究 总被引:1,自引:0,他引:1
采用三电弧双丝电弧焊,利用耐磨堆焊Fe-Cr-C-B系药芯焊丝作双丝,在Q235钢表面制备不同焊接工艺参数堆焊层,分析堆焊层熔合比、组织结构及耐磨性。结果表明:三电弧双丝药芯电弧焊堆焊可在较大范围调整焊接参数,获得较小的焊缝熔深、较低稀释率和较高的熔敷效率,耐磨性优异;当三电弧电流为150 A、电压30 V、焊丝伸出长度15 mm、送丝速度6 m/min、脉冲频率70 Hz时,堆焊层熔合比为0.07,堆焊层HRC为65,磨损量最小,耐磨性优良。 相似文献
5.
The catalytic properties of alumina-supported Ir catalysts (≈1 wt% Ir) were studied in the hydrodenitrogenation (HDN) of pyridine at 320°C and 20 bar of pressure in the absence as well as presence of parallel hydrodesulfurization (HDS) of thiophene. The effects of Ir precursor (Ir(AcAc)3, Ir4(CO)12, H2IrCl6, (NH4)2IrCl6), metal dispersion and sulfur addition were investigated. Ir4(CO)12 gave the most active catalyst which was ascribed to a lower amount of contaminants originated from the starting Ir compounds rather than to a better Ir dispersion. The decrease of Ir dispersion by sintering in air led to much higher decrease of the rate of C–N bond hydrogenolysis than that of pyridine hydrogenation. The Ir dispersion determined partly the HDN selectivity; a better dispersed Ir phase gave a lower amount of intermediate piperidine. Presulfidation of the reduced catalyst led to 20% decline of the rates of both consecutive HDN steps. An additional and much larger activity decline was caused by the simultaneous execution of HDS. The competitive adsorption of thiophene (or H2S) was selectively affecting C–N bond hydrogenolysis more than pyridine hydrogenation. The alumina-supported Ir catalysts possessed much higher HDN activity and HDN/HDS selectivity than a conventional NiMo system. 相似文献
6.
根据ISO-834标准升温曲线与结构钢强度和刚度随温度的变化曲线,采用非线性有限元法对不同的矢跨比的施威德勒型单层球面网壳结构进行了抗火分析,得到了一些结果,可为经济、科学的结构综合防火设计提供理论依据. 相似文献
7.
8.
M. Danielewski 《Oxidation of Metals》1986,25(1-2):51-82
The kinetics and mechanism of manganese sulfidation have been studied as a function of temperature (673–1373 K) and sulfur vapor pressure (10–105 Pa). It has been found that the rate-determining step of -MnS scale growth is the outward diffusion of metal. In the high-temperature range (>1000 K) coarsegrain scale is formed, and manganese diffuses in the form of Mn2+ cations and electrons via doubly ionized cation vacancies and electron holes (volume diffusion). In the low-temperature range (<800K), on the other hand, a fine-grain scale is formed, and manganese diffuses mainly through grain boundaries, but also in the ionized form. Finally, in the intermediate-temperature range (800–1000 K) grain-boundary diffusion prevails in the initial period of the reaction, and volume diffusion predominates during the later stages, as a result of grain growth of the scale. 相似文献
9.
提高三角形金刚石多晶烧结体耐磨性的研究 总被引:2,自引:0,他引:2
采用粉末冶金方法进行人造金刚石多晶体的烧结。研究了提高多晶烧结体耐磨性的方法。通过工艺配方的确定、合成条件的选择、调整真空净化处理工艺以及使用高品质人造金刚石等措施,提高了多晶烧结体的耐磨性。 相似文献
10.
通过九江乌石矶粮食中转库2万t克钢筋混凝土立筒库的基础设计实例,详细介绍了嵌岩灌注桩竖向承载力的几种确定方法。 相似文献