非稳定热塑性成型模拟中的时间差分耦合法

提出了时间差分耦合求解非稳定热塑性成型问题的方法——通过温度场和力能场的交替遗传计算来模拟变形与传热之间的互相影响,同时采用空间离散方法对毛坯性能不均匀现象进行描述。以圆柱坯热镦粗和方条料热拔长问题为例,论述了该方法在刚塑性变形分析中的应用。

Asymmetric cast-rolling of 1050 aluminum alloy strip under multi-energy field

Technological parameters of asymmetric cast-rolling under multi-energy field were investigated on horizontal twin roll caster（d400 mm×500 mm）, and their effects on structures and properties of 1050 strips were analyzed by comparing with traditional cast-rolling. Results show that when length of cast-rolling area is 70 mm, melt temperature of head box is 670 °C, cast rolling speed is 1.3 m/min, exciting current is 10 A, center frequency is（13±1） Hz, ultrasonic power is 200 W and ultrasonic frequency is（20±0.2） kHz, the 1050 strip with the best microstructure can be prepared successfully; its center segregated layer disappears; the average grain size is reduced by about 40%; the crystal grains are distributed evenly; micro segregation decreases obviously; the precipitated phases are distributed along the grain boundaries evenly; and the tensile strength, yield strength, elongation and micro-hardness of cast-rolled strip are improved by 22.6%, 23.66%, 38.75% and 9.90%, respectively.

Finite element analysis of pressure on 2024 aluminum alloy created during restricting expansion-deformation heat-treatment

Metals heat-treated under high pressure can exhibit different properties. The heat-induced pressure on 2024 aluminum alloy during restricting expansion-deformation heat-treatment was calculated by using the ABAQUS finite element software, and the effects of the mould material properties, such as coefficient of thermal expansion （CTE）, elastic modulus and yield strength, on the pressure were discussed. The simulated results show that the relatively uniform heat-induced pressure, approximately 503 MPa at 500 ℃, appears on 2024 alloy when 42CrMo steel is as the mould material. The heat-induced pressure increases with decreasing the CTE and the increases of elastic modulus and yield strength of the mould material. The influences of the CTE and elastic modulus on the heat-induced pressure are more notable.

Influence of fins on tractor-type podded propulsor performance

A mathematical model of podded propulsors was established in order to investigate the influence of fins. The hydrodynamic performance of podded propulsors with and without fins was calculated, with interactions between propellers and pods and fins derived by iterative calculation. The differential equation based on velocity potential was adopted and hyperboloidal panels were used to avoid gaps between surface panels. The Newton-Raphson iterative procedure was used on the trailing edge to meet the pressure Kutta condition. The velocity distribution was calculated with the Yanagizawa method to eliminate the singularity caused by use of the numerical differential. Comparisons of the performance of podded propulsors with different fins showed that the thrust of propeller in a podded propulsor with fins is greater. The resistance of the pod is also reduced because of the thrust of the fin. The hydrodynamic performance of a podded propulsor with two fins is found to be best, the performance of a podded propulsor with one fin is not as good as two fins, and the performance of the common type is the worst.

Performances of Five Representative Force Fields on Gaseous Amino Acids with Different Termini

There is a growing interest in the study of structures and properties of biomolecules in gas phase. Applications of force fields are highly desirable for the computational efficiency of the gas phase study. To help the selection of force fields, the performances of five repre- sentative force fields for gaseous neutral, protonated, deprotonated and capped amino acids are systematically examined and compared. The tested properties include relative conforma- tional energies, energy differences between cis and trans structures, the number and strength of predicted hydrogen bonds, and the quality of the optimized structures. The results of BHandHLYP/6-311＋＋G（d,p） are used as the references. GROMOS53A6 and ENCADS are found to perform poorly for gaseous biomoleeules, while the performance of AMBER99SB, CHARMM27 and OPLSAA/L are comparable when applicable. Considering the general availability of the force field parameters, CHARMM27 is the most recommended, followed by OPLSAA/L, for the study of biomolecules in gas phase

Eco-compensation of Wetlands in Yellow River Delta of Shandong Province,China

Wetlands play an important ecological role and provide many functions for people, yet wetlands are cur- rently decreasing and deteriorating. The ability to calculate an economic value for the loss of wetlands is becoming in- creasingly important for policy makers. In this study, remote sensing, field investigations, department visits, and other methods were used to survey wetland types, assess wetland area changes, and calculate wetland economic value. Mar- ket value loss and ecological ftmction value loss, caused by reduction of wetland area and environmental pollution were calculated using commonly accepted methods of market valuation, ecological valuation, environmental protection investment cost analysis, and outcome parameters. According to market value loss and ecological function value loss, preliminarily fund allocation for wetland and ecological compensation was calculated. This will provide an important reference for future Yellow River Delta eco-compensation studies.

Carburization of ferrochromium metals in chromium ore fines containing coal during voluminal reduction by microwave heating

Chromium ore fines containing coal (COFCC) can be rapidly heated by microwave to conduct the voluminal reduction, which lays a foundation of getting sponge ferrochromium powders with a lower content of C. Under the conditions of COFCC with n(O)-n(C) (molar ratio) as 1.00-0.84 and n(SiO2)-n(CaO) as 1.00-0.39, the samples were heated by 10 kW microwave power to reach the given temperatures and held for different times respectively. The results show that the low-C-Cr ferrochromium metal phase in the reduced materials forms before the high-C-Cr ferrochromium metal phase does. With increasing temperature the C content of ferrochromium metals is in a positive correlation with the content of Cr. The C content of ferrochromium metal in reduced materials is 0-10.07% with an average value of 4.68%. With the increase of holding time the Cr content in ferrochromium metals is in a negative correlation with the content of C, while the content of Fe changes in the contrary way. In the microwave field the kinetic conditions of carburization are closely related with the temperature of microwave heating, holding time and carbon fitting ratio.

Regional Allocation of CO_2 Intensity Reduction Targets Based on Cluster Analysis

To meet China＇s CO2 intensity target of 40%-45% reduction by 2020 based on the 2005 level, a regional allocation method based on cluster analysis is developed. Thirty Chinese provinces are classified into six groups based on economy, emissions, and reduction potential indicators. Under the equity principle, the two most developed groups axe assigned the highest reduction targets （55% and 65%, respectively）. However, their reduction potent!al is limited. Under the efficiency principle, the two groups with the highest reduction potential take the highest targets （48% and 61%, respectively）, but their economy is relatively backward. When equity and efficiency are equally weighted, the 5th group with a prominent reduction potential takes the highest target （54%）, and the 2nd and the 3rd groups with large industry scales take the second highest target （49%）. However, under all the three allocation schemes, the targets are not greater than 40% for the 4th and the 6th groups, which have a relatively low economic ability, emissions, and reduction potential. Due to inconsistency between economic and reduction potential, corresponding market mechanisms and policy instruments should be established to ensure equity and efficiency of regional target allocation.

An Improved Energy Balance Approach and Its Application in CHAMP Gravity Field Recovery

An efficient method for gravity field determination from CHAMP orbits and accelerometer data is referred to as the energy balance approach. A new CHAMP gravity field recovery strategy based on the improved energy balance approach IS developed in this paper. The method simultaneously solves the spherical harmonic coefficients, daily Integration constant, scale and bias parameters. Two 60 degree and order gravitational potential models, XISM-CHAMPO1S from the classical energy balance approach, and XISM-CHAMPO2S from the improved energy balance, are determined using about one year＇s worth of CHAMP kinematic orbits from TUM and accelerometer data from GFZ. Comparisons among XISM-CHAMPO1S, XISM-CHAMPO2S, EIGEN-CGO3C, EIGEN-CHAMPO3S, EIGEN2, ENIGNIS and EGM96 are made. The results show that the XISM-CHAMPO2S model is more accurate than EGM96, EIGENIS, EIGEN2 and XISM-CHAMPO1S at the same degree and order, and has almost the same accuracy as EIGEN-CHAMPO3S.

Effect of Saddle-Splay Elasticity on Stability of Disclination Rings in Nematic Liquid Crystals

In this paper, the stability of disclination ring in nematie liquid crystals is studied. In the presence of saddle-splay elasticity （characterized by k24） the disclination ring has a universal equilibrium radius. Depending on the values of the saddle-splay constant k24, the universal equilibrium radius is altered. When k24 〉 0.92k （m = 1/2） and k24 〉 0.88k （m =-1/2）, the disclination will be a point rather than a ring, where k is the Frank elastic constant in the one-constant approximation.

Examining Internal Factors That Affect Banks＇ Performance Through Panel Regression Analysis

The importance of banks which constitutes the main structure of the financial system increased with globalization on the both sides of country and firm. Factors that affect banks＇ performance can be macroeconomic or internal factors relevant with banks. In this study, different internal factors that can have an impact on banks＇ profitability are examined with panel data analysis. The dataset which include 22 private, state or foreign owned deposit banks provided from the Association of Turkish Banking. Data contains the period between 2003-2008. Equity profitability has been chosen as dependent variable. Independent variables are market share and number of branches. According to the regression results, market share and number of branches has positive and significant effect on profitability .

On China＇s Sustainable Development of Energy—Opportunity for the China＇s Nuclear Power Industry

According to the policy of reforming the power industry and accelerating the power construction of our country, by 2020, the national power consumption will be up to 3.6-3.7 trillion kilowatt-hours, the installed power-generating capacity is more than 800 million kilowatts. Therefore, the development of the China’s nuclear power industry faces good international and domestic environments and good historical opportunities. From the point of national energy security, economic development, and resource distribution, it is analyzed that China must develop the nuclear power in a more cost-effective style in this paper.

Novel Optimization Approach to Mixing Process Intensification

An approach was presented to intensify the mixing process. Firstly, a novel concept, the dissipation of mass transfer ability(DMA) associated with convective mass transfer, was defined via an analogy to the heat-work conversion. Accordingly, the focus on mass transfer enhancement can be shifted to seek the extremum of the DMA of the system. To this end, an optimization principle was proposed. A mathematical model was then developed to formulate the optimization into a variational problem. Subsequently, the intensification of the mixing process for a gas mixture in a micro-tube was provided to demonstrate the proposed principle. In the demonstration example, an optimized velocity field was obtained in which the mixing ability was improved, i.e., the mixing process should be intensified by adjusting the velocity field in related equipment. Therefore, a specific procedure was provided to produce a mixer with geometric irregularities associated with an ideal velocity.

Effect of Market Power in Electricity Markets

The main objective of this paper is to show an overview analysis of market power issues.Market power reflects the scarcity of power supply.It is the ability of a particular seller or group of sellers to maintain prices profitably above competitive levels for a significant period of time.Because the electric power system has its own characteristics that are different to other economic systems,both physical factors and economic factors of power system are key elements on this definition.We study some cases here,including different line limit levels,load levels and bid strategy through a market model based on OPF (optimal power flow) with a decommitment algorithm.

Impact of renewable power market penetration on coal power generation capacity growth

Since renewable energy sources are growing in importance, how well they can penetrate the energy market for power generation will be a very important factor in the role the coal industry will play in the future. This paper examined the displacement of coal power plant capacity from 2010 to 2050 by renewables with respect to three drivers assumed under various conditions： the American Recovery and Reinvestment Act （ARRA）, Greenhouse Gas （GItG） policy, and varying plant capital cost cases. The results by 2050 illustrate that renewable market penetration captures anywhere from 1.9% to 6.4% of potential coal power generation capacity additions. Renewable power generation capacity additions is expected to outpace coal power plant additions by 89% with respect to ARRA in 2050, however with no GHG policy coal power generation capacity build-outs will outpace renewables by as high as 809%. Finally, coal power generation is still projected to be the largest single energy source contributor to the electricity market making up 28.0% of total available capacity, while renewables are expected to only make up 16.3% of total available capacity.

Improving Global Competitive Capability, through Customization： Model, Method and Strategies

As the environment of market competition is rapidly changing, the model of competition also changes consistently. This paper focuses on the changing process of global competition model based on the analysis of production model and its tendency of development, especially analyses the positive effect of mass customization. The paper introduces the concept of market turbulence to decide the occasion of transformation to mass customization for industries/enterprises. Several transformation roadmaps to mass customization and competitive models and strategies are established.

Market-Based Solutions to Overcapacity：Principles and Measures

This paper takes stock of theoretical economic analyses of overcapacity,reveals the factors that induce actual capacity to deviate from market equilibrium, examines market-based mechanisms to resolve overcapacity, and identifies long-term mechanisms and assurances for market-based solutions to overcapacity. Given the limitations of market mechanism and the government's role, neither the market nor the government is able to resolve the problem of overcapacity on its own. In resolving overcapacity, market and the government should play their respective roles rather than replace one another. While the market is a dominant force in regulating capacity and achieving supply and demand equilibrium, the government should provide institutional assurances for effective market operation. Market-based solutions to overcapacity require the government to provide institutional assurances and create a system where market entities decide to enter and exit the market under effective restraints and incentives with a clear boundary.

Evaluation of power market designs on investment incentives and capacity adequacy

Electricity industry restructuring should not sacrifice supply security to pursue economic efficiency. Till now there is no academic consensus on which electricity market design provides the least distorting investment incentives. Alternative approaches that have been adopted around the world for ensuring the appropriate level of investment in electric generation capacity are discussed, and much attention is devoted on the evaluation of capacity payment systems. The finding is that on one hand, capacity payment systems have good effect on reducing spot market price volatility and increasing the volume of generating capacity at the costs of relatively high total electricity prices; on the other hand, however, they are not robust against either the abuse of market power in the energy market or being manipulated.

Voluntary Disclosure and the Type of Product Market Competition： Capacity vs. Price

This paper investigates empirically the effect of different types of product market competition on levels of voluntary disclosure of proprietary information in financial markets. The author proposes that there are two types of strategic interaction settings relevant to disclosure： capacity competition and price competition. Capacity competition drives firms to disclose more information to attain financial market valuation-related benefits, while price competition drives them to disclose less to protect long-term product market advantages. The author finds that the type of product market competition affects the level of voluntary disclosure over and above the finn＇s external financing needs documented in the previous literature. That is, firms engaged in capacity competition disclose relatively more information than those in price competition. Further analysis shows that capacity competition firms disclose more information than no-strategic-interaction benchmark firms but that price competition firms do not disclose less information than the benchmark firms.

The Application of English Songs in Higher Vocational College English Teaching

Due to the arrival of the era of globalization, English has become an important foreign language in China. People with high English proficiency have more opportunities and better competitiveness in the global job market. Therefore, more and more people attach importance to learn English. English songs play an important role in English teaching and they have been used as teaching materials in the field of language learning for a long time They can not only effectively stimulate students＇ interest in learning but also improve the quality and efficiency of English teaching. This instruction can enhance learners＇ motivation, learning attitude, and the comprehension of listening, speaking, reading, and writing. Some linguists believe that they can affect one＇s language learning abilities. Thus, more and more teachers and researchers try to find out how the English songs can improve the learners＇ English level. So, this paper aims to explore how to apply English songs to higher vocational English teaching.