Controllable preparation of two-mode entangled coherent states in circuit QED

Although the multi-level structure of superconducting qubits may result in calculation errors, it can be rationally used to effectively improve the speed of gate operations. Utilizing a current-biased Josephson junction （A-type rf-SQUID） as a tunable coupler for superconducting transmission line resonators （TLRs）, under the large detuning condition, we demonstrate the controllable generation of entangled coherent states in circuit quantum electrodynamics （circuit QED）. The coupling between the TLRs and the qubit can be effectively regulated by an external bias current or coupling capacitor. Further investigations indicate that the maximum entangled state can be obtained through measuring the excited state of the superconducting qubits. Then, the influence of the TLR [tecay on the prepared entangled states is analyzed.     

黄土丘陵区林草地枯落层盖度遥感估算研究

枯落层盖度的定量估算对于植被防蚀功效的评价具有重要作用。在陕北黄土丘陵沟壑区选取典型落叶林和退耕草地作为光谱测试样地,通过室内和野外实验分析枯落层—土壤混合场景的光谱变化规律,研究高光谱指数NDLI(normalized difference lignin index)和CAI(cellulose absorption index)估算枯落层盖度的有效性。结果表明,受颜色及含水量等因素的影响,不同盖度枯落层—土壤混合场景的光谱反射率呈现不同的变化规律。干和湿状态下,随着枯落层盖度的增加混合场景的NDLI、CAI指数值均呈现增大的趋势,CAI与枯落层盖度的相关性高于NDLI,R~2最高为0.98(阔叶林和退耕草地干的混合场景),CAI能够更有效地估算枯落层盖度。野外实测验证了室内实验结果,退耕草地混合场景的CAI值与枯落层盖度相关性最高(R~2=0.90),野外条件下两种高光谱指数估算枯落层盖度的有效性均有一定程度的降低。该研究为枯落层盖度的遥感定量反演提供了基础与依据。     

凝胶渗透色谱净化一气相色谱分离同时测定糙米中50种有机磷农药残留

研究了同时检测糙米中50种有机磷农药残留的方法。用乙酸乙酯提取，凝胶渗透色谱净化，环己烷-二氯甲烷(50：50，V/V)作为流动相，气相色谱-氮磷检测器检测。方法检出限为0．001～0．089mg／kg；相对标准偏差为1．7％～18．9％；40多种农药平均回收率在70％～120％。     

高富勒烯的提取,分离和分析

采用二硫化碳重结晶富勒烯混合物或二硫化碳二次抽提烟灰以提取高富勒烯（ｈｉｇｈｅｒｆｕｌｅｒｅｎｅｓ，Ｃｎ，ｎ＞７０）。产物经高效液相色谱分析，高富勒烯的含量从１％分别提高到４％和６％；经激光飞行时间质谱证明，产物中除含主要成分Ｃ６０和Ｃ７０以外，还含有Ｃ７６、Ｃ７８、Ｃ８２、Ｃ８４以及更高碳原子的富勒烯。     

Investigations into quantum correlation of coupled qubits in a squeezed vacuum reservoir

In this paper,we investigate the quantum correlation of coupled qubits which are initially in maximally entangled mixed states in a squeezed vacuum reservoir.We compare and analyze the effects of squeezed parameters on quantum discord and quantum concurrence.The results show that in a squeezed vacuum reservoir,the quantum discord and quantum concurrence perform with completely opposite behaviors with the change of squeezed parameters.Quantum discord survives longer with the increase of squeezed amplitude parameter,but entanglement death is faster on the contrary.The results also indicate that the classical correlation of the system is smaller than quantum discord in a vacuum reservoir,while it is bigger than quantum discord in a squeezed vacuum reservoir.The quantum discord and classical correlation are more robust than quantum concurrence in the two reservoir environments,which indicates that the entanglement actually is easily affected by decoherence and quantum discord has a stronger ability to avoid decoherence in a squeezed vacuum reservoir.     

凝胶渗透色谱净化-气相色谱分离同时测定糙米中50种有机磷农药残留

研究了同时检测糙米中50种有机磷农药残留的方法。用乙酸乙酯提取,凝胶渗透色谱净化,环己烷二氯甲烷(50∶50,V/V)作为流动相,气相色谱氮磷检测器检测。方法检出限为0.001～0.089mg/kg;相对标准偏差为1.7%～18.9%;40多种农药平均回收率在70%～120%。     

考虑制造商开设展厅的横向竞争博弈及定价-服务策略

从体验成本差异角度出发,将消费者分为高低体验成本两类,利用Hotelling模型构建消费者的效用函数。分析两个竞争性制造商关于开设展厅的Bertrand博弈以及展厅开设后的价格与服务决策。结果表明,当低体验成本消费者较多且产品匹配度较高或者低体验成本消费者较少时,两个制造商均开设展厅,但双方都获得最低的利润,陷入囚徒的困境;当低体验成本消费者较多且产品匹配度较低时,两个制造商都不开设展厅,双方达到帕累托最优。     

高富勒烯的富集方法研究

高富勒烯的含量很低，在总的富勒烯混合物中仅点１％左右，将其分离出来一般要经过提取、富集、高效液相色谱分离三个步骤。目前，高富勒烯的富集用得较多是Ｄｉｅｄｅｒｉｃｈ等采用的方法［１～４］，他们将富勒烯混合物在三根中性氧化铝柱中，用正己烷和甲苯（９５／５...     

实行BOPS模式是否总是有益的？与传统双渠道的对比研究

针对企业线上线下渠道融合战略中提出的BOPS(buy-online-and-pick-up-in-store)模式,在集中式和分散式两情境下分别构建并对比了BOPS和传统双渠道模型,探讨了在传统双渠道基础之上引入BOPS服务是否对企业而言总是有好处的,并分析了传统型消费者占比和消费者的服务敏感性程度对企业实施BOPS的影响。研究表明,企业是否在传统双渠道模式基础上增设BOPS服务,取决于市场中传统型消费者占比规模(即偏好传统零售的消费者)以及各类型消费者对线下服务的敏感性程度;BOPS模式下,当消费者BOPS行为的真正动机是出于欲体验线下零售服务时,对实施BOPS的制造商企业而言更为有利;同时,企业的产品定价和线下服务水平不仅需要考量生产、服务成本,同样需对消费者的服务敏感性有准确的了解和定位。     

Avoiding the decay of entanglement for coupling two-qubit system interacting with a non-Markov environment

The entanglement evolution of the coupled qubits interacting with a non-Markov environment is investigated in terms of concurrence.The results show that the entanglement of the quantum systems depends not only on the initial state of the system but also on the coupling between the qubit and the environment.For the initial state （|00 ± |11） /2^1/2,the coupled qubits will always been in the maximum entangled state under an asymmetric coupling.For the initial state （|01 ± |10） /2^1/2,in contrast,the entangling degree of the coupled qubits is always equal to unity and does not depend on the evolving time under the symmetric coupling.We find that the stronger the interaction between the qubits is,the better the struggle against the entanglement sudden death is.