2,963 research outputs found

    Placebo Analgesia, Acupuncture and Sham Surgery

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    Invasive procedures, such as surgery and acupuncture, are likely better than the others in terms of eliciting placebo analgesia. Understanding how invasive procedures can elicit enhanced placebo responses may provide new insights into mechanisms underlying placebo analgesia. In this essay, it is argued that sensory, cognitive and emotional factors are major determinants of the magnitude of placebo analgesia. Sham surgery and acupuncture are good examples of placebo interventions, which generate robust placebo responses through simultaneously manipulating such three factors

    Interference model of conical pick in cutting process

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    The load on conical pick is affected by many factors such as pick geometry and installation angle. In order to decrease the wear and vibration of pick in the cutting process by choosing proper impact angle, the interference mathematical models of straight and revolving cutting were established according to coal cutting theory. Based on this, coal cutting experiment was carried out with different impact angles ÎČ, different head face radii of pick body R and different cutting depths d to verify the mathematical model. The results indicate that the picks cutting into coal with a certain installed angle are prone to interfere with coal in the cutting progress. There is a crsitical impact angle, and it is different under different cutting conditions. The critical impact angle decreases with the head face radius of pick body R and cutting depth d. On the condition of given pick geometry and movement parameters, the cutting force of picks or cutting torque of cutting header decreases with the impact angle. When the impact angle of the pick is larger than the critical angle, the load on pick will increase prominently

    A Study on Water Utilization in Chinese Rural Areas

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    In China, because rural population is great and agriculture is very important in national economy, rural areas have becomes a main sphere of water consume. There exist the problems of water shortage and water waste in the countryside. The conflicts of water resource supply and demand between industry and agriculture are very conspicuous. Various factors that include ideology, finance, technology, management and policy restrict the rational and effective use of water resource. The survey on the villages of Jia Ge Zhuang and Yao Bai Zhuang in Ji County, Tianjin reflects these problems. The government tries to solve the problems by making laws and policies, as well as affording financial and technology support to towns and villages. At the same time, it is necessary for the government to make officials and farmers realize the importance of rational water usage and saving by doing propaganda, coordinating the inter-governments relations, and defining the departments’ duties. For realizing the objective of rational water usage, it is necessary to take measures to construct and perfect irrigation installations by both superior and local governments’ investment and farmers’ labor force. Key Words: Chinese Rural Areas, Water Resource, Rational Use, Farmland, Irrigation System RĂ©sumĂ©: En Chine,la population est grande et l’agriculture est trĂšs importante dans l’économie nationale. Les rĂ©gions rurales sont devenues un sphĂšre principal de la consommation d’eau. Il existe les problĂšmes d’insuffisance d’eau et le gaspillage d’eau dans la campagne. Les conflits sur les resources d’eau fournie et demandĂ©e entre industrie and agriculture sont trĂšs frĂ©quents. Les facteurs variĂ©s tels qu’idĂ©ologie, finance, technologie, management et politique limitent l’usage rationel et effectif de ressources d’eau. L’enquĂȘte sur les villages de Jia Ge Zhuang et Yao Bai Zhuang dans le pays Ji, Tianjin reflĂšte ces problĂšmes. Le government tente de rĂ©soudres les problĂšmes par l’élabortion des lois et les poliques, ainsi que le support financierl et technologique aux bourgs et villages. Au meme temps, il est nĂ©cessaire pour le government Ă  render conscients les officiels et les paysans l’ importance de l’usage rationel en Ă©conomisant par la publicitĂ©, en coordonnant les relations inter-governmentaux, et en dĂ©terminant les tĂąches des dĂ©partments. Pour la realiser l’objectif de l’usage d’eau rational, il est nĂ©cessaire de prendre des mesures pour construire et perfectionner l’ installations d’irrigation par l’investissement des governements supĂ©rieurs et locaux ainsi que les forces des labeurs. Mots clĂ©s: Les rĂ©gions rurales chionoises, Ressource d’eau, usage rationel, fermier, SystĂšme d’ Irrigatio

    Adaptive Dynamic Surface Control for Generator Excitation Control System

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    For the generator excitation control system which is equipped with static var compensator (SVC) and unknown parameters, a novel adaptive dynamic surface control scheme is proposed based on neural network and tracking error transformed function with the following features: (1) the transformation of the excitation generator model to the linear systems is omitted; (2) the prespecified performance of the tracking error can be guaranteed by combining with the tracking error transformed function; (3) the computational burden is greatly reduced by estimating the norm of the weighted vector of neural network instead of the weighted vector itself; therefore, it is more suitable for the real time control; and (4) the explosion of complicity problem inherent in the backstepping control can be eliminated. It is proved that the new scheme can make the system semiglobally uniformly ultimately bounded. Simulation results show the effectiveness of this control scheme

    (2,2â€Č-Bipyridine)(2-formyl-6-methoxy­phenolato)nickel(II) perchlorate

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    In the title compound, [Ni(C8H7O3)(C10H8N2)]ClO4, the NiII atom is in a slightly distorted square-planar coordination by two N atoms from the 2,2â€Č-bipyridine (bipy) ligand and two O atoms from the deprotonated 2-formyl-6-methoxy­phenolate (mbd) ligand. The bipy ligand is nearly coplanar with the NiII square plane, the Ni atom being only 0.042 (2) Å from the mean plane, whereas the benzaldehyde plane is folded with respect to the square plane, making a dihedral angle of 19.17 (8)°. One of the O atoms of the perchlorate anion is involved in a weak inter­action with the Ni atom, with an Ni—O distance of 2.5732 (18) Å. The packing is stabilized by weak C—H⋯O inter­actions

    Development of thermodynamic and kinetic databases in micro-soldering alloy systems and their applications

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    AbstractRecent progress in the development of thermodynamic and kinetic databases of micro-soldering alloys, which were constructed within the framework of the Thermo-Calc and DICTRA software, was presented. Especially, a thermodynamic tool, ADAMIS (alloy database for micro-solders) was developed by combining the thermodynamic databases of micro-solders with Pandat, a multi-component phase diagram calculation software program. ADAMIS contains 11 elements, namely, Ag, Al, Au, Bi, Cu, In, Ni, Sb, Sn, Zn and Pb, and can handle all combinations of these elements in the whole composition range. The obtained thermodynamic and kinetic databases can not only provide much valuable thermodynamic information such as phase equilibria and phase fraction, but also shows the kinetics and the evolution of microstructures when they are combined with some appropriate software programs and models, such as the phase field method and ADSTEFAN software. From the viewpoints of computational thermodynamics and kinetics, some technical examples were given to demonstrate the great utility of these databases for the applications in the development of micro-soldering materials. These databases are expected to be powerful tools for the development of micro-solders and Cu substrate materials, as well as for promoting the understanding of interfacial phenomena and microstructure evolution between solders and substrates in electronic packaging technology
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