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Search Results: 1 - 10 of 42575 matches for " Xu Anshuang "
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EFFECT OF SILICON ON THE TRANSITION OF BRITTLENESS IN A NICKEL BASE WROUGHT SUPERALLOY

Wang Yunshi,Bi Jing,Guan Xuemin,Zhang Xizhang,Wang Jingyun,Lin Shuzhi,Xu Anshuang,

金属学报 , 1979,
Abstract: The tensile strength, ductility or impact value of a wrought nickel base super-alloy Ni-15Cr-6W-3Mo-2Al-2Ti depend markedly upon the silicon content of thealloy. On plotting these mechanical properties vs the silicon content which rangesfrom 0.1 to 0.89%, a saddle shown by the existence of a minimum at about 0.4-0.6% Si occurs. There is reason to believe that such a saddle behavior may be caus-ed by the variation of mechanical properties with the type, amount and morpho-logy of carbides as well as with the sequence of carbide precipitation in the alloyas influenced by its silicon content. Thus, the amount of M_6C and M_(23)C_6 precipi-tated along the grain boundaries would appear to proceed in four stages as follows: 1. For silicon content up to 0.1%, globular M_(23)C_6 may be the sole type ofcarbide formed; 2. In the range from 0.1 to 0.4% Si, besides M_(23)C_6, M_6C begins to appearand increases with increase of silicon content. The morphology of the carbidesseems to be different, however, being in a discontinuous, blocky form; 3. In the range from 0.4 to 0.6% Si, continuous films of M_6C were present.As might be expected, this type of carbide is very detrimental to the tensile andimpact properties at room temperature. The precipitation of M_(23)C_6 was slowed downor even suppressed; 4. In the range from 0.6 to 0.89% Si, M_6C may be altered to discontinuous,blocky form, whereas M_(23)C_6 may be very much limited. In conclusion, the detrimental effect of carbide is mainly associated with itsfilm-like morphology especially along the grain boundaries. Of course, carbides ingranular form are good strengtheners. According to prevailing view, criterion for the formation of either M_6C orM_(23)C_6 in nickel base superalloys would seem to be the relative Mo and W con-tents, e. g. if Mo+1/2W>6%, M_6C will be formed. Present work indicates that si-licon plays as equally important role in the formation of M_6C besides the Mo andW contents of the wrought nickel base superalloys.
A Decision Problem of Hotels on Setting Online-Exclusive-Rooms in E-Commerce Age  [PDF]
Liang Xu, Xiaoyan Xu
Journal of Service Science and Management (JSSM) , 2014, DOI: 10.4236/jssm.2014.74029
Abstract:

Due to the rapid development of information technology, customers’ consumption pattern in hotel industry has dramatically changed, and many people book rooms through some professional online platforms. Hotel managers need to redesign their sale channel structures by incorporating online platforms, in order to increase profit. This paper focuses on a revenue maximization problem for a hotel which cooperates with an online platform. Two cooperating forms are investigated and compared. Specifically, one intuitive form is named complete sharing, in which all the hotel rooms are shared with the online platform for booking. The other form is named setting online-exclusive-rooms (OERs), in which the hotel set a fixed quantity of rooms for exclusively booking from the online platform. By building a loss queueing model, this paper finds some properties of the optimal quantity of OERs in the latter form. Factors affecting the selection and how they affect the selection are also investigated.

An Algorithm for Improving Throughput Guarantee of Topology-Transparent MAC Scheduling Strategy  [PDF]
Chaonong Xu
Wireless Sensor Network (WSN) , 2010, DOI: 10.4236/wsn.2010.210096
Abstract: Topology-transparent MAC scheduling strategies nowadays are all based on combinatorial design. To get throughput guarantee, a cover-free set is output as scheduling strategy of network. In this paper, we aim to modify the cover-free set so that better throughput can be guaranteed. At the first step, the redundant slot of the cover-free set is proposed and found to have negative influence on the minimal guaranteed throughput. Second, we prove that any subset of a cover-free set is still a cover-free set after its redundant slots were squashed out. Our algorithm chooses the subset which has the maximal number of redundant slots, squashes all of its redundant slots, and then designates it as the network scheduling strategy. Therefore, better through- put can be guaranteed if the squashed subset is adopted as network scheduling strategy. For any topology- transparent node scheduling strategy, both the increased minimal throughput and decreased maximal transmission delay can be gotten by just using our algorithm as an extra accessory.
Experimental and Numerical Study of the Effect of Surround Protection Technique on the Strain Measurement for Offshore Jacket Platform  [PDF]
Yongjun Xu
Engineering (ENG) , 2011, DOI: 10.4236/eng.2011.35056
Abstract: For strain measurement on offshore jacket platform in deep water, waterproof of strain foil is always an important issue, especially, due to the high pressure in deep water. The waterproof is difficult in two places, one is between the matrix structure and the protection structure, and another is between the lead wires and the protection structure. The surround protection technique discussed in this paper is conventional and ideal, and can be operative for a long time, up to five years. In this method, a metal case and tube is added on the local position, which increases the local rigidity, but the effect on the measurement of strain is not well studied. In this paper, the effect of the surround protection technique on the strain measurement is studied by using numerical and experimental methods, and the results show that the measurement error is well in the range permitted by engineering practice.
Editorial: Special Section on Reinforcement Learning and Approximate Dynamic Programming  [PDF]
Xin Xu
Journal of Intelligent Learning Systems and Applications (JILSA) , 2010, DOI: 10.4236/jilsa.2010.22008
Abstract: .
A Kind of Potential Practical Sensors of Metamaterial in Electromagnetic Flaw Nondestructive Testing  [PDF]
Zhanxian Xu
Engineering (ENG) , 2011, DOI: 10.4236/eng.2011.37090
Abstract: We present a new kind of method of electromagnetic flaw nondestructive testing with coating of metamaterials and simulation near electromagnetic field property for test crack. The simulation of improving a Nondestructive testing (NDT) probe electromagnetic radiant property by Metamatrials (MMs) covering a tiny current element is investigated and analyzed using Ansoft HFSS based on finite element method (FEM), which permittivity and permeability are negative. Electromagnetic model: Ideal MMs ball shell with inner radius of 1 mm and outer radius variation, and the shell’s relative permittivity and relative permeability are all –3.0, dielectric loss tangent and magnetic loss tangent are all 0.1; and exciting current element length is with 0.3 mm, diameter 0.2 mm, value 1 mA at frequency 10 GHz; and simulation is with radiation boundary conditions. The simulating near electromagnetic field variety with ratio of inner radius and out radius, and so near or local field of MMs sensor on a surface crack, as well as comparing near field value of sensor with coating common material are finished. Results can be seen that MMs film sensor near electromagnetic field and radiation properties are obviously better than other two kinds of structures without coating medium and coating with common medium, and Metamaterial may be opened out some new kinds of sensors in electromagnetic flaw nondestructive testing for potential practical applications in future.
Rethinking the China-US Balance of Trade: 1990-2005  [PDF]
Xiaoping Xu
iBusiness (IB) , 2012, DOI: 10.4236/ib.2012.41006
Abstract: Since 1993, American trade deficit with China is expanding and the gap is becoming increasingly bigger. The widening bilateral trade imbalance has caused growing concerns. This paper, by using empirical method and adjusting the data of trade from 1989 to 2005, finds that the causes of the imbalance of China-US trade are as follows: 1) the imbalance of domestic demands of US; 2) the adjustment of American economic structure, and 3) the growing of multinational enterprises. The paper also finds that the imbalance of China-US trade is not as big as it was reported by US; the imbalance of China-US trade is an inevitable result of economic development, and the trade deficit does not necessarily mean a loss of profit. In fact, American investors and consumers have greatly benefited from China-US trade.
Application Study on Multi-Vary Analysis  [PDF]
Xiaomin Xu
Modern Mechanical Engineering (MME) , 2013, DOI: 10.4236/mme.2013.31005
Abstract:

In this article, we studied the bearings made by one company in Shanghai. Through statistical process controlling the quality characteristic of bearings’ diameters and multi-vary analysis is applied to find the key variation factors which have an influence on the quality characteristic of the bearings, the quality level of the bearings of this company is improved.

DNA Circuit System and Charge Transfer Mechanism  [PDF]
Kunming Xu
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.510B077
Abstract:

Based on the accurate identification of chemical structures as electric elements, we described charge transport mechanism in a DNA molecule by a stepwiseLCoscillatory circuitry, in which every base pair is a capacitor, every phosphate bridge is an inductor, and every deoxyribose is a charge router. The circuit model agrees with established experimental evidence that has supported super-exchange and hopping mechanisms so far. This alternative charge transport mechanism through both strands of DNA matches the fidelity and reliability of its chemical structure.

On the Evaluation of Performance System Incorporating “Green Credit” Policies in China’s Financial Industry  [PDF]
Lan Xu
Journal of Financial Risk Management (JFRM) , 2013, DOI: 10.4236/jfrm.2013.22005
Abstract:

The main work of this paper is aimed, through utilizing the two-stage optimization theory, to estimate the green distance functions and Malmquist green growth indexes for the China’s main commercial banks and relevant financial institutions, and to further set up an overall appraisal index system to assess their performance in implementing the “Green Credit” principles. The paper also analyzes effects of the “Green Credit” policies influential on revenue achievements, as well as performs a decomposition analysis of the above impacts. The carry-outs of the paper may serve as useful references and guiding means in achievingChina’s economic transitional strategies of sustainable development.

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