In-situ comprehensive calibration of a tri-port nano-electro-mechanical device

We report on experiments performed in vacuum and at cryogenic temperatures on a tri-port nano-electro-mechanical (NEMS) device. One port is a very nonlinear capacitive actuation, while the two others implement the magnetomotive scheme with a linear input force port and a (quasi-linear) output velocity port. We present an experimental method enabling a full characterization of the nanomechanical device harmonic response: the nonlinear capacitance function C(x) is derived, and the normal parameters k and m (spring constant and mass) of the mode under study are measured through a careful definition of the motion (in meters) and of the applied forces (in Newtons). These results are obtained with a series of purely electric measurements performed without disconnecting/reconnecting the device, and rely only on known dc properties of the circuit, making use of a thermometric property of the oscillator itself: we use the Young modulus of the coating metal as a thermometer, and the resistivity for Joule heating. The setup requires only three connecting lines without any particular matching, enabling the preservation of a high impedance NEMS environment even at MHz frequencies. The experimental data are fit to a detailed electrical and thermal model of the NEMS device, demonstrating a complete understanding of its dynamics. These methods are quite general and can be adapted (as a whole, or in parts) to a large variety of electromechanical devices.     

渐开线齿轮变位系数的确定

本文提出在给定端面重合度ε_α时,确定齿轮的变位系数、以及确定在无干涉条件下的变位系数极限值的方法。本文没有采用计算量大且精度不高的迭代法,而是用封闭图公式的解法。在任意选择ε_α数值时,确定变位系数x_1几乎是不可能的。但是在ε_α≤ε_(αmax)区域内却是可以找出x_1的解的(其中ε_(cmax)是重合度的最大值)。下面确定ε_(αmax)。若齿轮传动的总变位系数为∑x,单位法向模数(m_n=1)的齿顶圆直径为d_α,可得无侧     

A new laser Doppler flowmeter prototype for depth dependent monitoring of skin microcirculation

Laser Doppler flowmetry (LDF) is now commonly used in clinical research to monitor microvascular blood flow. However, the dependence of the LDF signal on the microvascular architecture is still unknown. That is why we propose a new laser Doppler flowmeter for depth dependent monitoring of skin microvascular perfusion. This new laser Doppler flowmeter combines for the first time, in a device, several wavelengths and different spaced detection optical fibres. The calibration of the new apparatus is herein presented together with in vivo validation. Two in vivo validation tests are performed. In the first test, signals collected in the ventral side of the forearm are analyzed; in the second test, signals collected in the ventral side of the forearm are compared with signals collected in the hand palm. There are good indicators that show that different wavelengths and fibre distances probe different skin perfusion layers. However, multiple scattering may affect the results, namely the ones obtained with the larger fibre distance. To clearly understand the wavelength effect in LDF measurements, other tests have to be performed.     

美国火电厂烟气排放限值及控制技术

美国火电厂烟气排放限值及控制技术在过去的37年内不断发展进步.受限制的排放物越来越多,而且对每种污染物的限值日益严格.总结了当今美国使用的排放限值及控制技术,并展望了未来的排放限值及潜在的排放控制技术.     

右值引用概述

右值引用（Rvalue Reference）是对C＋＋语言的一个技术小扩展。有了它,程序员可以在逻辑上规避临时对象的无谓复制,即搬移语义（move Semantics）,并可实现完美转发（perfect forwarding）。本文是对右值引用这个C＋＋语言新特性的概述。     

A global optimization strategy for predicting alpha-helical protein tertiary structure

We present a global optimization strategy that incorporates predicted restraints in both a local optimization context and as directives for global optimization approaches, to predict protein tertiary structure for alpha-helical proteins. Specifically, neural networks are used to predict the secondary structure of a protein, restraints are defined as manifestations of the network with a predicted secondary structure and the secondary structure is formed using local minimizations on a protein energy surface, in the presence of the restraints. Those residues predicted to be coil, by the network, define a conformational sub-space that is subject to optimization using a global approach known as stochastic perturbation that has been found to be effective for Lennard-Jones clusters and homo-polypeptides. Our energy surface is an all-atom 'gas phase' molecular mechanics force field, that is combined with a new solvation energy function that penalizes hydrophobic group exposure. This energy function gives the crystal structure of four different alpha-helical proteins as the lowest energy structure relative to other conformations, with correct secondary structure but incorrect tertiary structure. We demonstrate this global optimization strategy by determining the tertiary structure of the A-chain of the alpha-helical protein, uteroglobin and of a four-helix bundle, DNA binding protein.     

精灵王子手办帅气降临

传说中的精灵一族除了以美貌身手见称外,长寿亦是其特点之一。在这漫长岁月中,经历无尽空虚与寂寞,百年孤独非笔墨可形容。在众多奇幻作品及RPG游戏中出现的精灵和人类外形很像,它耳朵尖尖,是美丽长寿之种族。一般它们以森林为家(暗精灵则住在地下),喜爱自然,情感细腻,声音旋律优美,天生就是诗人和舞蹈家;在昏暗条件下它的视野也是人     

真名法典——莉丝 花瓣之风清纯动人

E2046推出此款来自游戏《真名法典》的手办模型莉丝。游戏故事发生在兰斯海姆大陆,1000年前大陆曾因为战争而频临灭绝边境,就在这个时候英雄斯托拉斯自我牺牲     

Transport Properties of K_xV_2O_5·nH_2O Nanocrystalline Films

Five different compositions of K x V 2 O 5 ·nH 2 O(where x=0.00,0.0017,0.0049,0.0064 and 0.0091 mol) were prepared by the sol-gel process.Electrical conductivity and thermoelectric power were measured parallel to the substrate surface in the temperature range of 300-480 K.The electrical conductivity showed that all samples were semiconductors and that conductivity increased with increasing K content.The conductivity of the present system was primarily determined by hopping carrier mobility.The carrier density was evaluated as well.The conduction was confirmed to obey non-adiabatic small polaron hopping.The thermoelectric power or Seebeck effect,increased with increasing K ions content.The results obtained indicated that an n-type semiconducting behavior within the temperature range was investigated.