Changes of Some Capacities and Failure Mode of Ni/MH Batteries During Cycling

The changes of capacities of positive and negative electrodes, reserve capacities of charging and discharging, and the weight of batteries during cycling have been determined. The increase of the discharging reserve capacity due to the conjugated electrochemical reactions of the oxidation of hydrogen storage alloy is estimated. The results show that the failure mode of Ni/MH batteries developed is as follows: during the increase of cycles, the hydrogen storage alloy is oxidized continuously and the charging reserve capacity is decreased rapidly while the discharging reserve capacity is increased gradually, thus the internal pressure is increasing, first H 2 leaks out from the battery, then the mixture of H 2 and O 2. The leakage of gases and the total reaction of oxidation of the alloy consume H 2O, and the surface oxides on the alloy increase, so that the internal resistance of the battery increases.

Changes of Fiscal and Financial Capacity in a Reforming China

China finds itself in a dual transitional period forboth its economy and its society with the govern-ment playing key role. The government is obliged tomaintain and reinforce its capacity to mobilize and allo-cate social resources, to maintain a stable developmentof both the economy and society.the paper,concernedwith the source of funds, has divided national capacityinto national fiscal capacity and national financialcapacity.By calculation and analysis of the fiscal ca-pacity and financial capacity,we will explain the role ofthe finance industry as "secondary public finance."

Giant isothermal entropy change In(111)-oriented PMN-PT thin film

An isothermal entropy change of 240 nm(111)-oriented PMN–PT 65/35 film near the ferroelectric Curie temperature,relative cooling power(RCP)and change of heat capacity have been investigated.The extracted data characterized giant isothermal entropy change of more than 16 J/kgK in electric field shift△E of 455 kV cm^(-1),which is nearly twice than that found for PbZr_(0.9)5Ti_(0.05)O_(3)thin film at 492 kV cm^(-1)near the Curie point.Furthermore,the RCP≈700 J/kg and change of heat capacity≈233 J/kgK in electric field shift△E of 747 kV cm^(-1).

Study of ZrO_2 nanopowders based stearic acid phase change materials

ZrO2 nanopowders based stearic acid phase change materials （PCMS） were prepareo oy mgn-energy milling. The concept of heat capacity factor （HCF） was used to analyze the thermal properties of the materials. The heat storage property of PCMs, containing the same content of stearic acid （23~ by mass） in the starting materials but synthesized by different technical processes, was investigated by using HCE It was found that there were vast influences of different dispersants on the heat capacity. The samples orelaared with chloroform provided the best heat storage ability in all samples tested.

Theoretical work on magnetocaloric effect in La_(0.75)Ca_(0.25)MnO_(3)

In this work,a phenomenological model is applied to describe the magnetocaloric effect for the La_(0.75)Ca_(0.25)MnO_(3)system near a second-order phase transition from a ferromagnetic to a paramagnetic state.Based on this model,it can predict the values of the magnetocaloric properties from calculation of magnetization as a function of temperature under different external magnetic fields.The magnetic entropy change reaches a peak of about 5.39 J/(kg·K)at 257 K upon 4 T applied field variation.TheΔSM distribution is much more uniform than that of gadolinium,which is desirable for an Ericson-cycle magnetic refrigerator.

Theoretical investigations on electrocaloric properties of(111)-oriented PbMg_(1/3)Nb_(2)/3O_(3) single crystal

The electrocaloric(EC)effect accompanied with the ferroelectric to paraelectric phase transition in(111)-oriented PbMg_(1/3)Nb_(2)/3O_(3)(PMN)is investigated.It is shown that the largest change TDis 0.37 K in 3 kV/cm electric field shift near the Curie temperature of 221 K;that is,the cooling TDper unit field(MV/m)is 1.23×10^(-6) m·K/V.This value is significantly larger,and comparable with the value of 0.254×10^(-6) m·K/V for PbZr_(0.95)Ti_(0.05)O_(3)thin film under larger electric field shift ED=30 kV/cm.Thus,the EC effect of(111)PMN single crystal provides cooling solutions at low temperatures,and opens more opportunities for practical application in cooling systems.

Electrocaloric properties of Zr-modified Pb(Mg_(1/3)Nb_(2/3))O_(3) polycrystalline ceramics

In this work,electrocaloric properties of Pb(Mg_(1/3)Zr_(2x/3)Nb_(2(1-x)3))O_(3-x/3) polycrystalline ceramics for different stoichiometric compositions have been investigated.The results show that largest changes(ΔT)are in range of 1.07 to 4.84 K in 10 kV cm^(-1) electric field change.These values are significantly large,and are comparable with values of other lead-containing ceramics under the same or larger electric field shift.The conclusion is that these materials are excellent candidates for working materials in refrigeration and liquefaction devices in a wide temperature range.