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991.
This paper considers such a group G which possesses nontrivial proper subgroups H 1 ,H 2 such that any proper subgroup of G not contained in H 1 ∪ H 2 is p-closed and obtains that if G is soluble,then the number of prime divisors contained in |G| is 2,3 or 4;if not,then it has a form x N where N/Φ(N) is a non-abelian simple group.Then the structure of such a group is determined for p = 2,H 1 = H 2 under some conditions. 相似文献
992.
In this paper we formulate a continuous-time behavioral (à la cumulative prospect theory) portfolio selection model where the losses are constrained by a pre-specified upper bound. Economically
the model is motivated by the previously proved fact that the losses occurring in a bad state of the world can be catastrophic
for an unconstrained model. Mathematically solving the model boils down to solving a concave Choquet minimization problem with an additional upper bound. We derive the optimal solution explicitly for such a loss control model. The optimal
terminal wealth profile is in general characterized by three pieces: the agent has gains in the good states of the world,
gets a moderate, endogenously constant loss in the intermediate states, and suffers the maximal loss (which is the given bound
for losses) in the bad states. Examples are given to illustrate the general results. 相似文献
993.
In order to determine the copper content x of copper Chevrel compound CuxMo6S8?y(0?y?0.4) as a function of copper activity aCu and sulfur deficit y, a solid state electrochemical cell, Cu/Rb4Cu16I7Cl13/CuxMo6S8?y/Pt, was constructed and coulometric titration studies were made at 400 K. For the evaluation of the coulometric titration data, measurements were made on the electronic conductivity of copper-ion conductor Rb4Cu16I7Cl13. Also, a brief investigation was made on the condition of formation of single phase Chevrel CuxMo6S8?y with varying x and y at 1000°C. The structural change of CuxMo6S8?y with a change in x and y was studied by the X-ray diffraction method. It was found that x for constant aCu decreases with increasing y. The maximum value xmax of x in CuxMo6S8?y in equilibrium with metallic copper was found to be expressed by . In the region of y<0.3, xmax exceeded 4, contrary to a presupposition that xmax is less than 4. X-ray analysis revealed that most of the copper Chevrel compounds denoted by CuxMo6S8 so far were sulfur deficient ones with y?0.4. The importance of sulfur deficit on the properties of the copper Chevrel compound was emphasized. 相似文献
994.
激光诱导荧光光谱方法测量气溶胶颗粒研究 总被引:1,自引:4,他引:1
采用激光诱导荧光光谱方法测量大气中气溶胶颗粒物的散射荧光特性,同时用飞行时间方法测量颗粒物的动力学直径大小。给出了实验系统设计、测量方法、颗粒粒径分布图及散射荧光强度分布谱图的对比,并对多组实验数据进行分析。同时讨论了利用颗粒物散射荧光百分比分析方法判别生物粒子和非生物粒子的可行性。 相似文献
995.
A carrier method for separating out-of-plane displacement from in-plane components based on large imageshearing shearography is presented. A reference surface is fixed on the side of a test object. They are illuminated by two expanded symmetric illuminations respectively. The carrier is introduced by rotating the reference surface to modulate the displacement of an object. By using Fourier transform to demodulate the modulated fringe pattern, two phase maps, which include out-of-plane and in-plane displacements, can be obtained. Then the out-of-plane displacement can be easily separated from in-plane displacement by subtraction and addition of the two unwrapped phase distributions. The principle of the method is presented and proved by a typical three-point-bending experiment. Experimental results show that the method enjoys high visibility of carrier fringes. The system does not need a special beam as a reference light and has simple optical setup. 相似文献
996.
997.
For the Shanghai Synchrotron Radiation Facility (SSRF) and future Shanghai Free‐Electron Laser projects, ground vibration is an important factor and, in order to attenuate it, the construction of a deep tunnel is under consideration. This paper concentrates on the investigation of ground vibration at different underground levels down to 60 m below surface, in order to understand the effect of vibration attenuation with depth. The effect of traffic is also studied using a 10 ton truck, with ground motion compared in different directions. Finally, a summary and some suggestions on these two projects are given. 相似文献
998.
E. Camarillo H. Murrieta J.M. Hernandez R. Zoilo M.C. Flores T.P.J. Han F. Jaque 《Journal of luminescence》2008,128(5-6):747-750
Lithium niobate (LiNbO3) crystals doped with chromium ions show a clear green colouring reflecting the absorption profile of the dominating [Cr]Li defect centres. A significant change in its colouration takes place when it is co-doped with other valency impurities such as Mg2+, Sc3+ and W6+, above a certain threshold concentration. This concentration singularity has been attributed to the formation of [Cr]Nb centres coexisting with the [Cr]Li centres.In this work, we extended the investigation on the effect of co-dopant ions in Cr:LiNbO3 to tetravalent cation such as GeO2. A singularity in the relative intensity of the 4A2→4T1 and 4A2→4T2 absorption band was observed for a concentration of ~1.5 mol%, compared with 4.5 mol% for Mg2+. The photoluminescence emission spectra also reveal a new emission band, at a lower energy than the [Cr]Li centre, corresponding to this threshold concentration. A charge compensation model is proposed to explain the role of cation impurities and results are compared with those of other valence impurities. 相似文献
999.
基于GEANT4模拟了HIRFL CSRm内靶实验终端的CsI(Tl)电磁量能器系统,给出了CsI电磁量能器的最佳设计参数及可能达到的性能.结果表明,设计的CsI(Tl)电磁量能器系统能够满足所研究的物理要求. Based on the GEANT4, the performance of the electromagnetic calorimeter (EMC) of the internal-target detector at HIRFL-CSRm is simulated. The simulation results show that 1.5%—3% of the energy resolution σ_E/E and 2° of the polar angular resolution σ_θ can be obtained. The invariant mass of the π~0 decay can be reconstructed well. The performance can meet the requirement of studying the proposed physics at HIRFL-CSRm. 相似文献
1000.
在水热反应条件下合成出具有红磷锰矿结构的Mn5(PO3(OH) ) 2 (PO4 ) 2 (H2 O) 4单晶 ,在X ray单晶结构分析的基础上 ,对其固体紫外可见漫反射光谱、红外光谱、荧光光谱和热重光谱进行了研究。结果表明 ,构成该化合物的PO4 四面体及MnO6 八面体通过共顶点或共棱方式相连接 ,与P ,Mn配位的氧分为 3类 :即端基氧 (Od)、二桥氧 (Ob)和三桥氧 (Oc)。因而在 2 10和 2 5 0nm左右出现了Od→Mn和Ob ,c→Mn的荷移跃迁吸收谱带 ;在 10 0 0~ 110 0cm- 1 处 ,P—O的伸缩振动峰分裂为 3个 ;70 0~ 980cm- 1 处存在 3类Mn—O的伸缩振动。对标题化合物分别采用 2 18和 310nm的光激发 ,分别在 35 4和 4 13nm产生强而尖锐的荧光光谱发射峰 ,表现了很强的光学效应。热重分析表明该化合物在 2 70℃以下结构保持稳定 ,在 2 70~36 0℃范围内失去配位水。量化计算得单点能为 - 4 5 5 8 6 5 95 5 5 1a u ;前线轨道能量HOMO(Alpha) =- 0 2 80 80a u ,LOMO(Alpha) =0 0 15 2 7a u ,能隙为 0 2 96 0 7a u ;HOMO(Beta) =- 0 2 5 919a u ,LOMO(Beta)=0 0 0 10 8a u ,能隙为 0 2 6 0 72a u ;偶极矩为 4 2 0 82Debye。 相似文献