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981.
通过对场地地质条件、施工方法、塌陷过程的调查,分析了在嘉陵江岸坡地段的轻轨大溪沟车站挖孔桩施工场地因流砂而导致的地面塌陷原因,同时介绍了在考虑防洪度汛和斜坡安全的情况下所采取的一些特殊措施及其处理效果。 相似文献
982.
Shi Dongjian Sui Jing Duan Fang Chen Mingqing He Bingxiao 《Reactive and Functional Polymers》2013,73(8):1015-1021
Thermal-sensitive poly(N,N-diethylacrylamide) grafted poly(acrylonitrile/styrene) (PDEAm-g-PAN/PSt) polymeric microspheres were prepared from PDEAm macromonomer, St and AN by dispersion copolymerization. The polymeric microspheres had raspberry-like morphology with large surface area. Palladium–metal (Pd–M) (M: copper, Cu, silver, Ag) bimetallic nanoparticles were stabilized on the surface of the PDEAm-g-PAN/PSt microspheres via the coordinate interaction between amide groups in PDEAm and metal ions with the reduction of the corresponding ions. Transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and thermogravimetry analysis (TGA) results confirmed the size and composition of the immobilized Pd–M nanoparticles. The Pd–M bimetallic nanoparticles showed superior catalytic efficiencies for the reduction of 4-nitrophenol (4-NP) than the monometallic nanoparticles. The catalytic activity of the Pd–M bimetallic catalysts could be controlled by the molar ratio of Pd and M ions and composition of Pd–M nanoparticles. Moreover, the catalytic property of the Pd–M nanoparticles could be regulated by temperature and increased with increasing the temperature above lower critical solution temperature (LCST). Furthermore, the Pd–M nanoparticles could be easily recycled and reused to catalyze 4-NP for five times without loss of activity. These bimetallic nanoparticles possess great potential in future practical application in catalytic technology. 相似文献
983.
石油取芯钻头石墨模具在热压过程中的受力状况分析 总被引:1,自引:0,他引:1
石墨模具以其优良的性能被广泛应用于热压孕镶金刚石钻头的制造。本文设计了两种规格相同(直径均为216mm),但端部形状不同的石油取芯钻头的石墨模具,并利用有限元分析软件ANSYS对它们在热压过程中的受力状况进行了分析。分析结果表明:在18MPa压力下,圆弧形钻头的模具在胎体与模具接合处出现了应力集中,超过模具的极限抗拉强度,导致模具破裂。因此,在设计钻头的石墨模具时,应考虑到钻头的端部形状,参考有限元分析结果再对模具进行设计,有助于优化设计,降低试验和生产成本。 相似文献
984.
985.
改性沥青制备过程复杂,针入度的影响因素较多,试验主要介绍了基质沥青、改性剂的种类、改性剂加入量、剪切时间、测试基准面等因素对改性沥青针入度的影响。 相似文献
986.
987.
Ruquan Liang Dong Liang Fusheng Yan Zhangqing Liao Guangdong Duan 《Microgravity science and technology》2011,23(1):79-88
A numerical simulation for a bubble motion near a wall under microgravity, relevant to material processing such as crystal
growth in space, is presented based on a mass conservation level set algorithm to predict the bubble behavior affected by
the near wall. The simulation for the wall effect on the bubble driven by an external acceleration parallel with the near
wall referred to as g-jitter confirms for the first time the existence of the wall attractive force to the bubble near the
wall under certain conditions such as the initial distance between the bubble and the wall, density and viscosity ratios between
the bubble and surrounding liquid under microgravity. The wall effect mechanism is explained, and the results show that the
wall attractive force increases with the increasing of density ratio. Moreover, the simulation for the wall repulsive effect
on the bubble near the wall under microgravity has been carried out as well. 相似文献
988.
联醇催化剂双塔并联同时升温还原较两个单塔先后单独升温还原可以缩短升温还原时间,增加有效生产时间,提高企业生产效益。实践证明,双塔并联升温还原操作基本平稳,两塔催化剂活性表面良好。正常运转时,两塔转化率均达79%,粗甲醇含量在95%以上。 相似文献
989.
超临界流体的应用及进展 总被引:5,自引:0,他引:5
介绍了超临界流体的性质及超临界反应、超临界二氧化碳萃取在医药、食品、化工、环保等方面的应用及进展。 相似文献
990.
Seven kinds of used mineral lubricating oils, including hydraulic oils, film bearing oils, steam turbine oil and gear oils, were recycled by reclamation and adding additives. Physical and chemical properties of the recycled oils were measured and their lubrication performances were evaluated by the original and modified four-ball testers. Worn surfaces were analyzed by energy dispersive X-ray spectroscopy and Raman microscope. The recycling costs of burning, re-refined and refortified were estimated. Results showed that physical and chemical properties of the refortified oils were improved effectively and became in the industrial access standard. With the different friction materials under different loads, refortified oils provided excellent lubrication performances, much better than those of fresh oils. Because of additives replenished, the different lubrication films could form on the worn surfaces. A rough financial calculation revealed that the refortification process could produce the most economic value among the three methods. 相似文献