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排序方式: 共有9208条查询结果,搜索用时 687 毫秒
991.
Lee Dae-Won Lee Jung-Hyun Chun Bae-Hyeock Lee Kwan-Young 《Plasma Chemistry and Plasma Processing》2003,23(3):519-539
The direct hydroxylation of benzene using molecular oxygen by atmospheric pulse DC corona discharge was investigated. The conversion of benzene increased with the increase of oxygen content and input voltage but the selectivity of phenol decreased due to the formation of polymerized products. The reactivity was also influenced by the kind and content of background inert gas. By using argon as background gas, we could get 2.2% of phenol yield at 60°C and 1 atm with energy consumption of 50 W. The strategy of reductive oxidation, which added hydrogen to the reactant, was not favorable to the phenol formation in this reaction system. The polymerized product showed the oligomeric character and the analysis of its chemical structure with FT–IR was presented. 相似文献
992.
M.C. Saint-Lager Y. Jugnet L. Piccolo J.C. Bertolini O. Robach C. Walker 《Surface science》2005,587(3):229-235
The (N × 1) reconstruction (N = 5-6) of the clean Pd8Ni92(1 1 0) surface has been investigated by surface X-ray diffraction. A good fit with experimental data collected under UHV conditions is obtained when introducing undulations in the outer dense rows, constituted mainly of Pd atoms which strongly segregate to the surface. This reconstruction can be regarded as a way to relax the strains induced on the bigger Pd surface atoms, at least partially. The modifications of the surface were studied under butadiene then hydrogen as well as during butadiene hydrogenation at elevated pressure at 300 K and the (N × 1) reconstruction was found to be still present. The main changes are observed under pure hydrogen and during butadiene hydrogenation. 相似文献
993.
V. I. Bukreev 《Journal of Applied Mechanics and Technical Physics》2006,47(5):679-687
A review of the information available in the literature is given, and new experimental data on the depth and discharge at
the dam site after a total and a partial dam break are presented. It is shown that in the case of a partial dam break with
the formation of a rectangular breach, the specific discharge per unit width of the breach is higher than the specific discharge
in the case of a total dam break with the same excess initial energy in the headwater.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 47, No. 5, pp. 77–87, September–October, 2006. 相似文献
994.
995.
介绍了一种水冷、陶瓷封接结构的空心阴极放电装置.研究了He、H_2、N_2在120nm~20Onm范围内该装置的真空紫外辐射特性,获得了100~600mA电流范围内的辐射强度与放电电流的关系,以及充气气压变化对它的影响.实验表明:在实验条件下,主要发射谱线为氮的原子线和氦的离子线;辐射谱线强度在0.03~0.72mW·cm~(-2);气压改变时,N_2、H_2辐射强度有一极大值,而He的离子线辐射强度则出现二个极大;在He/H_2混合气体放电时,随着He的加入,氢分子带光谱有明显下降. 相似文献
996.
997.
从转动矩阵理论与实验两方面研究了结合脉冲梯度场的选择性形状脉冲的相位特性,结果表明:单梯度自旋回波(SPFGSE)和双梯度自旋回波(DPFGSE)对于对称和反对称的形状脉冲,都能很好地克服其相位畸变;而双梯度自旋回波(DPFGSE)对于非对称的形状脉冲也能克服其相位畸变;双选择性单梯度自旋回波无法克服形状脉冲的相位畸变. 相似文献
998.
杨自祥 《核聚变与等离子体物理》1988,(1)
磁通计是一个被低电感电阻短路的自积分单匝线圈。由于它具有时间响应快,抗干扰能力强,不影响束流传输等优点,主要用于测量脉冲电子束加速器的二极管发射电流。同时,也可做为电流探针,用来监测其它快速变化的电流。 相似文献
999.
This paper describes the operational details of the single-cavity race track microtron of this laboratory. The machine is
capable of providing electrons of 8 MeV energy at 1 mA peak current. Important parameters of the machine and beam handling
system are studied and the results are reported. 相似文献
1000.
K. Farahmand 《Queueing Systems》1996,22(3-4):425-435
We analyze a model queueing system in which customers cannot be in continuous contact with the server, but must call in to request service. If the server is free, the customer enters service immediately, but if the server is occupied, the unsatisfied customer must break contact and reapply for service later. There are two types of customer present who may reapply. First transit customers who arrive from outside according to a Poisson process and if they find the server busy they join a source of unsatisfied customers, called the orbit, who according to an exponential distribution reapply for service till they find the server free and leave the system on completion of service. Secondly there are a number of recurrent customers present who reapply for service according to a different exponential distribution and immediately go back in to the orbit after each completion of service. We assume a general service time distribution and calculate several characterstic quantities of the system for both the constant rate of reapplying for service and for the case when customers are discouraged and reduce their rate of demand as more customers join the orbit. 相似文献