共查询到20条相似文献，搜索用时 156 毫秒
1.
Based on minimum output energy,an improved blind multiuser detection algorithm is proposed by the use of Hopfield neural network.Compared with traditional algorithms,the proposed algorithm does not need the circuit for constraints.The resources are greatly saved and the complexity is reduced as well.The simulation results show that the performance of the improved algorithm is similar to that of the optimal multiuser detection algorithm which is not suitable for the mobile station.Compared with the traditional gradient blind multiuser detection algorithm,the convergence speed of the improved algorithm is quickened. 相似文献
2.
1.The CommonCatCats and humans have been 1)associated for nearly 10,000years.
Cats save energy by sleeping for 2)an average of 13 to14 hoursa day.
A group of cats is called a 3)clowder.A male cat is called a tom.
A female cat is called a molly or queen,while young cats arecalled kittens. 相似文献
3.
Delta function is an important function in mathematics and physics. In this paper, the Laplace transforms of δ(t)and δ(t-τ)have been discussed in detail. After the Laplace transform of δ(t)is analyzed, the author has found that three aspects should be taken into account, i.e. τ→0+, τ→0- andτ=0; and it is the same with the Laplace transform of δ(t-τ). Then the results of the Laplace transform of Delta function have been obtained in a rigorous and comprehensive sense. 相似文献
4.
Solar energy is a natural resource which can be harnessed to provide clean electricity for hydrogen production systems. However, this technology is not widely used because of control issues, particularly for hydrogen refuelling stations. At present, direct or DC-DC converter couplings are the most common system configurations for hydrogen refuelling stations. However, these system configurations are costly and suffer from gas shortage at hydrogen refuelling stations. Furthermore, the hydrogen produced by such system configurations varies considerably depending on the levels of solar radiation. In order to address these issues, a new system configuration is proposed, incorporating the feedback signal of the storage level in the control system. The photo- voltaic （PV） system, electrolyzer, and storage tank are integrated with a fuzzy logic controller （FLC） to determine the backup current compensation for electrolyzer operation in order to obtain the minimum power required for hydrogen production. The proposed FLC is constructed with three input variables which are the PV current, hydrogen storage level, and the battery state of charge. The rules-based fuzzy inference process is based on the proposed configuration which combines the advantages of direct and DC-DC converter coupling configurations. The simulation results show that the proposed configuration offers better adapta- bility to variable radiation conditions compared to other methods. This gives a more promising option for ensuring the adequacy of hydrogen supply at hydrogen refuelling stations. 相似文献
5.
Under an in-phase assumption, the complete charging for an energy harvesting system is studied, whichconsists of a piezoelectric energy harvester （PEH）, a bridge rectifier, a filter capacitor, a switch, a controller and arechargeable battery. For the transient charging, the results indicate that the voltage across the filter capacitor increasesas the charging proceeds, which is consistent with that reported in the literature. However, a new finding shows thatthe charging rate and energy harvesting efficiency decrease over time after their respective peak values are acquired.For the steady-state charging, the results reveal that the energy harvesting efficiency can be adjusted by altering thecritical charging voltage that controls the transition of the system. The optimal energy harvesting efficiency is limitedby the optimal efficiency of the transient charging. Finally, the relationship between the critical charging voltage andthe equivalent resistance of the controller and rechargeable battery is established explicitly. 相似文献
6.
吴崇彪 《宿州教育学院学报》2006,9(6):137-139
本文通过对莎士比亚四大悲剧文本的细致分析,探讨了莎剧中小人物对莎氏悲剧主题的作用,指出其有两点作用:一、揭示主题;二、深化主题。 相似文献
7.
Code-switching is a widespread phenomenon throughout the world,which has generated much discussion and debate.This paper presents the characteristics,function and motivation of code-switching between Chinese and English. 相似文献
8.
Showmore Mafirakureva 《海外英语》2012,(9):276-280
If an uncut woven pile fabric is to be subjected to compressive load in use its compression resilience performance becomes very crucial.In order to optimize the extent of recovery in fabric thickness when the applied force is removed,thirteen uncut woven pile fabric samples were woven and tested on KES-G5 Hand Type Compression Tester (small compress Hammer).The results show that the above parameters influence compression resilience property of the uncut woven pile fabrics,and the structural factors have a more pronounced effect as compared to effect of fibre and yarn type. 相似文献
9.
LI Shi-jie ZHAO Ling-zhi LENG Gang-song .Devision of Teaching Research Quzhou Education Commission Quzhou P.R.China 《上海大学学报(英文版)》2007,(2)
In this paper,the T_φ-convex functions were introduced as a generalizations of convex functions.Then the character- istics of the T_φ-convex functions were discussed.Furthermore,some new inequalities for the T_φ-convex functions were derived. 相似文献
10.
Context that belongs to linguistics has been chosen to research,since many difficulties emerge in dealing with understanding and expressing source text in the process of translation.And context is one of the major factors exerting impact on translation. 相似文献
11.
钯钇氢分子结构与热力学性质 总被引：1，自引：1，他引：0
徐友辉 《内江师范学院学报》2008,23(4):40-42
在钯Pd和钇Y原子相对论有效原子实势和基函数SDD下,使用密度泛函理论B3LYP方法计算得到钯钇氢气态分子的结构、光谱数据、能量E、熵S等性质．计算固体钯钇氢的E和S时,近似以气体分子的电子能和振动能代替固体分子的E,用电子熵和振动熵代替固体分子的S．在此近似条件下,计算了不同温度下的热力学函数及生成反应的标准焓变△H°、标准熵变△S°和标准自由能变△G°．结果表明：固体钯钇氢分子具有热力学稳定性． 相似文献
12.
论证了在汽液界面也存在一种自发形成的非平衡有序结构,此结构由分子因热运动而在汽液两相之间迁移而自发形成.针对该有序结构提出了一个实验模型,该模型中每个自发过程都会使某环节向平衡靠近而却同时导致另一环节偏离平衡,自发过程之间的联动和互补作用形成一个自持续的循环机制.分析表明,通过适当的动力学机制可使汽液界面的相变过程总是保持不平衡,从液相净迁移进汽相的分子能以设定的路径返回液面并在此过程中释放分子势能做功.提出与麦克斯韦妖功能类似的非耗能有序化自组织机制是可能存在的,分子的微观无序运动能转化为宏观的定向运动. 相似文献
13.
何吉欢 《上海大学学报(英文版)》1997,(1)
lintroductionIn1954,byso-calledtry-and-el.l.ormethodHull]deducedtheHu-Washizupl'inciple,whichplaysan.importantroleinthehistoryofvariation.In1964,ChienlZIsystematicallydiscussedtheLagrangemultipliermethod.Withthemethod,hesuccessfullydeducedHu-Washizuprinci… 相似文献
14.
Jihuan He Ph. D. 《上海大学学报(英文版)》1997,1(1):36-41
The paper has proved that Hellinger-Reissner and Hu-Washizu variational principles are but equivalent principles in elasticity
by following three ways: 1) Lagrange multiplier method. The paper points out that only a new independent variable can be introduced
when one constraint equation has been eliminated by one Lagrange multiplier, which must be expressed as a function of the
original variable(s) and/or the new introduced variable after identification. In using Lagrange multiplier method to deduce
Hu-Washizu principle from the minimum potential energy principle, which has only one kind of independent variable namely displacement,
by eliminating the constraint equations of stress-displacement relations, one can only obtain a principle with two kinds of
variables namely displacement and stress; 2) involutory transformation, with such method Hu-Washizu variational principle
can be deduce directly from the Hellinger-Reissner variational principle under the same variational constraints of stress-strain
relation, and vice verse; 3)semi-inverse method, by which both of the above variational principles can be deduced from the
minimum potential energy principle with the same variational constraints. So the three kinds of variational functions in Hu-Washizu
variational principle are not independent to each other, the stress-strain relationships are still its constraint conditions. 相似文献
15.
谈英语委婉语及其语言文化因素 总被引：1，自引：0，他引：1
委婉语是人类语言使用过程中的一种普遍现象,在不同的语言群体和不同的社会层次都有一些特定的委婉表达方法。作为一种常见的语言现象,委婉语的使用具有重要的社会功能。从语言文化因素角度对委婉语加以分析,可以看出委婉语具有积极和消极两方面的社会功能,这些功能受与其密切相关的语言文化因素的制约。 相似文献
16.
Based on energy considerations, it is possible to obtain the differential equations of motion of any physical system. A statement of equilibrium involving operations on energy functions is the Lagrange equation d / OT a7' D aOV dt (aq,) -aq aq + aq. Providing that the kinetic energy T, potential energy V, and dissipation function D can be written, the differential equations of the system are obtained by following a straightforward systematic procedure. It is not necessary to employ Kirchhoff's laws or Newton's force law to obtain the equations of electrical and mechanical systems. Rather, the two kinds of systems fall within the scope of this general method. The energy method is particularly useful in dealing with electromechanical systems and with mechanical systems that combine rotation and translation. Nonlinear as well as linear systems can be handled with equal ease. Versatility of the method is shown by its application to various examples, chosen in more or less increasing order of complexity. A set of tables is provided, listing the energy functions for each basic type of electrical, mechanical and electromechanical element. Those charged with teaching students the different disciplines of dynamics and electric circuits should find herein a common meeting ground wherein one general method suffices to yield the necessary differential equations. 相似文献
17.
通过二次组态相互作用方法 QCISD,选用CC-PVTZ基组对H2,HF分子进行结构优化,分别选用Morse函数、Rydberg函数、赝高斯函数、Murrell-Sorbie函数、Hulbret-Hirschfelder函数对H2,HF基态分子进行研究,利用最小二乘法拟合,得到势能函数解析表达式,导出力常数(f2,f3,f4)和光谱常数(ωe,Be,αe,ωe,χe),结果表明:用Murrell-Sorbie函数计算出的f2,f3,f4与(ωe,Be,αe,ωe,χe)与实验数据非常吻合,H2,HF基态分子结构及势能函数可用Murrell-Sorbie函数正确表达。 相似文献
18.
依据微观反应静力学原理推导出ScF分子基态可能的电子状态和离解极限,分别利用Los Alamos的有效核加上DZ和Stuttgart等人所用的有效核近似基组,在不同的计算水平(包括耦合簇理论的CCSD、密度泛函理论的B3P86和B3LYP)上计算了ScF的分子结构、振动频率和离解能,结果证明密度泛函方法B3P86结合SDDALL基组是最优的,用优选的B3P86方法结合SDDALL基组扫描ScFX1∑+态的势能曲线.拟合得到了Murrell-Sorbie解析势能函数,并且在平衡位置附近做Dunham展开,由此计算了相应的振转光谱,与其它理论和实验结果吻合的很好. 相似文献
19.
P300/CNV事件相关电位刺激器的研制与应用 总被引：2，自引：0，他引：2
通过研制一种特殊的刺激器,使不具备事件相关电位P300、CNV(关联性负变)检测功能的普通诱发电位仪实现P300、CNV的检测。自主设计P300/CNV刺激器的研制方案、电路和程序等,通过调试修正,完成刺激器开发。P300/CNV事件相关电位刺激器达到设计要求,能记录出较为理想的P300和CNV波形。成功研制出P300/CNV刺激器,此刺激器有一定通用性,可与诱发电位仪或生物信号处理系统配合使用;建立了适用于此刺激器的P300、CNV检测方法。此刺激器有一定实用性,可节约实验经费。目前市面上未见有类似产品,此刺激器已获中华人民共和国实用新型专利(ZL专利号:200420081185.5)。 相似文献
20.
粒子穿越方势阱时的反射相位时间研究 总被引：1，自引：0，他引：1
为了更深入地了解相位时间的物理意义,讨论了量子粒子穿越一维方势阱时的反射相位时间计算得出的反射相位时间和透射相位时间数值相等并在一定条件下出现负值现象认为,量子力学中粒子穿越方势阱时,不论粒子最终是被反射或透过势阱,这 过程可只用一个物理量—量子力学中的能速来正确描述 相似文献