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排序方式: 共有289条查询结果,搜索用时 15 毫秒
281.
J. Récamier M. Gorayeb W. L. Mochán J. L. Paz 《International Journal of Theoretical Physics》2008,47(3):673-683
We construct nonlinear coherent states by the application of a deformed displacement operator acting upon the vacuum state
and as approximate eigenstates of a deformed annihilation operator. These states are used to evaluate the temporal evolution
of the average value of the momentum and the diplacement coordinate as well as their dispersions. We also construct even and
odd combinations of these nonlinear coherent states and compute their second order correlation function in order to analyze
their statistical behavior. 相似文献
282.
网格频域分析法在变形测量中的应用 总被引:3,自引:2,他引:1
将频域分析法与网格法相结合,研究了网格频域分析法对位移的测量问题,该方法可以对网格图象中的位移场等变形信息进行全场、快速、自动处理,同时还可以实现位移场的分离.文中介绍了网格频域分析法原理,最后用计算机进行了数字仿真,并且进行了实验测试,结果表明该方法是可行的. 相似文献
283.
Y.W. Liu C. Xie M. Deng Q.H. Fang B. Jin 《Theoretical and Applied Fracture Mechanics》2009,52(3):146-153
This work deals with the influence of Kelvin-type viscoelastic interface on the generation of screw dislocations near the interfacial blunt crack tip in light of a pair of concentrated loads. The stress fields for dislocation and concentrated load have been obtained by using the integral transform and conformal mapping, the stress intensity factor have been studied, the image force acting on dislocation has been analyzed. The region rb where n screw dislocations are generated by a pair of concentrated loads and dislocation number are obtained by displacement compatibility and stress compatibility conditions of self-consistent and self-equilibrated systems. The results show that: the force acting on dislocation starts with the value that a perfectly bonded interface, then with relaxation of the imperfect interface; the shield effect for dislocation decreases as time goes by; in addition, with time elapsing, the influence of material shear modulus rate on shielding effect becomes weaker and weaker. The scale of multiplier α(rb/a) increases with relaxation of imperfect interface, the larger ratio of crack geometry c/a and the smaller ratio of shear modulus μ1/μ2 will lead the higher scale of multiplier. When μ1/μ2 = 1, the screw dislocations number first increases and then decreases with relaxation of imperfect interface, In addition, it possesses the highest value at t0 ≈ 1 and tends to vanish at t0 = ∞. When μ1 < μ2, the screw dislocations number increases with relaxation of imperfect interface. When μ1 > μ2, the screw dislocations number first increases then decreases with relaxation of imperfect interface, and possesses the highest value at t0 ≈ 1, the negative value are exclude from the discussion. 相似文献
284.
285.
为使表面增量拉曼散射(SERS)衬底的制备方法简单快速且提高的基底增强效果,采用置换反应的制备方法,用锌片和硝酸银反应制备出微米银结构SERS活性基底,其具有稳定性好,易保存,制备方法简单,过程快速等特点。用扫描电子显微镜观察得银微米材料表面形貌呈均匀对称的树枝状结构。实验中控制置换反应的时间分别为40,50,60 s时,得到的树枝状银微米材料的长度分别为3,5,10 μm左右,分支分别为700 nm,2 μm,3 μm,发现随着置换反应的时间的增长,微米银树枝及分枝的长度越长,且树枝分枝上逐渐长出纳米级“树叶”结构, 使得微米级银树枝表面具有纳米结构。并且将微米银材料置于硅片上作为SERS衬底,并以罗丹明6G为探针分子,用激发波长为1 064 nm的傅里叶变换拉曼光谱仪检测,研究其在表面增强拉曼光谱中的应用,结果表明树枝状银微米材料有很好的SERS特性,其中置换反应时间为40 s时制备的微米银树枝的增强效果最佳,其增强因子可达到103左右,并且采用用表面活性剂PVP处理硅片的方法后,保持其他条件不变,微米银衬底的SERS增强效果得到进一步加强,增强因子达到104左右。此外,将树枝状银微米材料用水可封存数月,且实验结果的重复性较好。 相似文献
286.
A new general solution in terms of two scalar potential functions for classical elastodynamics of x
3-convex domains is presented. Through the establishment and usage of a set of basic mathematical lemmas, a demonstration of
its connection to Kovalevshi–Iacovache–Somigliana elastodynamic solution, and thus its completeness, is realized with the
aid of the theory of repeated wave equations and Boggio’s theorem. With the time dependence of the potentials suppressed,
the new decomposition can, unlike Lamé’s, degenerate to a complete solution for elastostatic problems.
相似文献
287.
288.
Haipei Zhao Xuehao Xiu Dr. Mingqiang Li Prof. Shaobo Dai Mingyang Gou Leyang Tao Prof. Xiaolei Zuo Prof. Chunhai Fan Prof. Zhongqun Tian Prof. Ping Song 《Angewandte Chemie (International ed. in English)》2023,62(14):e202214450
Dynamic interactions of enzymes, including programmable configuration and cycling of enzymes, play important roles in the regulation of cellular metabolism. Here, we constructed a super DNA-enzymes molecule (SDEM) that comprises at least two cascade enzymes and multiple linked DNA strands to control and detect metabolism. We found that the programmable SDEM, which comprises glucose oxidase (GOx) and horseradish peroxidase (HRP), has a 20-fold lower detection limit and a 1.6-fold higher reaction rate than free enzymes. An SDEM can be assembled and disassembled using a hairpin structure and a displacement DNA strand to complete multiple cycles. An entropically driven catalytic assembly (catassembly) enables different SDEMs to switch from an SDEM with GOx and HRP cascades to an SDEM with sarcosine oxidase (SOX) and HRP cascades in over six orders of magnitude less time than without the catassembly to detect different metabolisms (GO and sarcosine) on demand. 相似文献
289.
大多数量子系统都与外界环境之间存在某种热交换或热纠缠, 受量子光学双光子纠缠态表象启发, 本文将建立热纠缠态表象. 根据 Takahashi 与 Umezawa 提出的热场动力学理论, 热场混合态可以等效为一个量子纯态.因此, 任意量子态在环境温度不为零(T ≠0) 时, 系综期望值可以等效成对量子纯态的平均值. 在温度趋向于无穷大时, 可以得到热真空态的极限形式. 类似于相干态, 利用平移算符对热真空态极限形式做平移操作后, 即可得到热相干态(也称为热纠缠态) . 热纠缠态表象可以将密度算符ρ =|m> 相似文献