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1.
A highly efficient one-pot synthesis of 1,8-dioxooctahydroxanthenes under solvent-free conditions catalyzed by sulfonic acid covalently anchored onto the surface of silica gel is reported.All types of aldehydes,including aromatic,unsaturated,and heterocyclic,are used.The silica gel/sulfonic acid catalyst (SiO2-R-SO3H) is completely heterogeneous and can be recycled.  相似文献   
2.
We present an efficient scheme for sharing an arbitrary m-qubit state with n agents. In our scheme, the sender Alice first shares m Bell states with the agent Bob, who is designated to recover the original m-qubit state. Furthermore, Alice introduces n- 1 auxiliary particles in the initial state |0), applies Hadamard (H) gate and Controlled-Not (CNOT) gate operations on the particles, which make them entangled with one of m particle pairs in Bell states, and then sends them to the controllers (i.e., other n - 1 agents), where each controller only holds one particle in hand. After Alice performing m Bell-basis measurements and each controller a single-particle measurement, the recover Bob can obtain the original unknown quantum state by applying the corresponding local unitary operations on his particles. Its intrinsic efficiency for qubits approaches 100%, and the total efficiency really approaches the maximal value.  相似文献   
3.
固有频率集聚时处理振型的一个方法   总被引:10,自引:0,他引:10  
1.前言现在作固有振动分析的结构愈来愈复杂了。由此带来的困难不仅在于自由度众多,还在于常有频率集聚现象,即在很小一段频率区间内有很多个固有频率。当频率集聚在一起时,相应的固有振型对结构的某些物理参数变化很敏感。在正问题中,例如用有限元模型计算固有频率和振型,由于这种敏感性,刚度阵与质量阵的某些误差就会导致计算所得的集聚组振型有更大的误差;在反问题中,集聚组对应的振型对测量误差很敏感,因而也难  相似文献   
4.
We investigate the behavior of quantum dissonance in the anti-ferromagnetic XXZ spin S = 1/2 chain, which exhibits a quantum phase transition. Based on a unified view of quantum and classical correlations, quantum dissonance is analytically calculated and is compared with entanglement, discord, and classical correlations for the ground state of the system. It is found that the nearest-neighbor quantum dissonance achieves an extremum and exhibits the sharpest change at the critical point. Therefore, quantum dissonance may serve as a more efficient indicator of quantum phase transitions in the XXZ spin chain.  相似文献   
5.
逆向信息和道德风险下的供应链线性激励契约研究   总被引:10,自引:0,他引:10  
本文我们利用委托代理理论,研究了供应商和零售商之间的利益博弈.考察了两类不对称信息——逆向信息和道德风险并存下的供应链线性契约.通过把问题归结为一个二层规划问题,求解得到了相关结论:与道德风险下的线性契约[12]相比,两类不对称信息的存在,使得对零售商的激励变得更加复杂.通过数值试验,比较了线性甄别契约和线性混同契约,发现对于作为委托人的供应商而言,甄别契约比汇同契约更有效率.  相似文献   
6.
We show that controlled-controlled-NOT(CCN)operation-based entanglement purification protocol can be further improved.CCN protocol requires Bell state measurements after performing the CCN operations.In the original CCN protocol,the measured states are assumed to be destroyed.However,if controlled-NOT gates are used to perform such Bell state measurements,in some unsuccessful situations of the CCN protocol,one can further purify the two mixed entangled states which are to be measured.In this way,the total efficiency of the CCN protocol is further increased.  相似文献   
7.
A new debenzylation of benzyl esters by silica-supported sodium hydrogen sulfate is described. The debenzylation could be achieved selectively and efficiently in good to excellent yields without affecting sensitive functional groups such as nitro, unsaturated bonds, and ethyl ester.  相似文献   
8.
本文通过含锌冲剂治疗小儿血锌低下24例.对患儿临床症状改善情况进行比较,发现改善厌食症状有效率达86.36%,反应呼吸道感染有效率达95.24%.对缺锌组治疗前与正常儿童血铸进行比较.治疗组血锌比正常组明显偏低,P<0.001,其差异有极显著意义.对治疗组治疗前后的血锌等元素进行测定与比较,口服含锌冲剂治疗后,血锌大部分升高,经l检验,P<0.005,其差别有显著意义。而Zn/Cu比值在治疗后明显升高,P<0.001,更说明含锌冲剂对调整微量元素有肯定的效果。  相似文献   
9.
周万松 《应用声学》1983,2(2):29-33,22
自1939年将超声波应用于治疗某些关节痛、神经痛之后,随着时间的进展,其应用范围逐渐扩大.我国超声波疗法是解放后才开始研究与应用的.随着医疗卫生事业的发展,超声波疗法的应用也在不断发展,在长期的临床实践中积累了较丰富的经验.为了有利于超声波疗法的迅速发展,现将我国超声波疗法的进展情况综述如下.  相似文献   
10.
本文介绍了根据椭球光学性质研制的FJG-1型椭球反射镜检测仪。它为检验回转椭球反射镜建立了面积有效率、光轴偏移量、f_1值允差与反射率四项技术指标,并给出了检测仪的设计原理与操作方法。最后对仪器的误差及运行效果进行了分析。  相似文献   
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