烹饪职业教学改革的质变效应源于“多媒体”技术

在当下现代化信息时代背景下，多媒体技术蓬勃发展，其应用已普及渗透到国民经济与社会生活的各个角落，正在对人类的生产方式、工作方式乃至生活方式带来巨大的变革。在烹饪职业教学也产生了积极的效应，作为实践性、直观性较强的烹饪教学，多媒体技术的介入，无疑为教与学提供了直观、方便的教学手段，同时也为学生提供了最理想的教学环境。“多媒体”技术注入到烹饪职业教学中，使烹饪教学呈现出全新的教学模式、现代化的教学手段和理念。

Increasing effect of metamorphism on rock properties

This work studied the effect of increasing degree of metamorphism on the properties of rocks.The properties investigated are the physical,mechanical and dynamic parameters.They are important inputs in the design of many mining and civil engineering techniques such as in tunnelling,slope stability and dynamic activities associated with seismicity and fragmentation.This work compared the degree of metamorphism examined through petrographic studies of the Transvaal Sequence in South Africa with the properties of the rocks.The study shows that as the effect metamorphism increases,the state of stress,compaction of grains,cementation and the brittleness of the rocks increases.In addition,increase in the metamorphic effect increases the value of the rock property.The degree of metamorphism of an outcrop is the key factor influencing its property value.Therefore the metamorphism effect of an outcrop may act as a guide to its engineering properties.

Cooling Device Using the Natural Convection, Phase Change of Substance and Capillary Effect

Paper deals about testing of device with gravity assisted heat pipes and about researching of wick heat pipes used to effective heat transfers from power switches of energy converter. At first, to simulate ambient condition was designed thermostatic chamber where was monitoring temperature course on main parts of cooling device （energy converter, air cooler and heat pipes） at various position of cooling device. It was found, if the cooling device is in tilt position the cooling performance is better. But if the tilt angel of gravity assisted heat pipe is higher the heat transfer is lower. From reason improve heat transfer cooling device at tilt angle are manufactured heat pipes with the sintered, mesh screen and grooved capillary structures and tested their thermal performance at vertical and tilt angel 45~ position by calorimetric method. Article describes manufacturing process and thermal performance measuring method of wick heat pipes. This experiment testify that the wick heat pipe is able operate at tilt angle position than gravity assisted heat pipe and application of wick heat pipes into cooling device will improve his cooling performance.

Effect of impurity scattering on superconductivity in K2Cr3As3

Impurity scattering in a superconductor may serve as an important probe for the nature of superconducting pairing state. Here we re- port the impurity effect on superconducting transition temperature Te in the newly discovered Cr-based superconductor K2Cr3As3. The resistivity measurements show that the crystals prepared using high-purity Cr metal （≥99.99%） have an electron mean free path much larger than the superconducting coherence length. For the crystals prepared using impure Cr that contains various non- magnetic impurities, however, the Tc decreases significantly, in accordance with the generalized Abrikosov-Gor＇kov pair-breaking theory. This finding supports a non-s-wave superconductivity in K2Cr3As3.

Surface composition-tunable octahedral PtCu nanoalloys advance the electrocatalytic performance on methanol and ethanol oxidation

The synthesis of surface composition-tunable Pt-based octahedral nanoalloys is key to unravel the structureproperty relationship in fuel cells. Herein, we report a facile route to prepare composition-tunable Pt Cu octahedral nanoalloys by using halogen ions(Br-or/and I-) as composition modulators. Among these Pt Cu octahedral nanoalloys,Pt59 Cu41 octahedron exhibits the highest catalytic activity and durability in alkaline solution. The specific activity/mass activity of Pt59 Cu41 octahedron is 20.25 m A cm^-2/3.24 A mg^-1 Pt,which is 6.64/5.3 times higher than commercial Pt black in 0.5 mol L^-1 CH3 OH, respectively. In the case of using ethanol(0.5 mol L^-1) as fuel source, Pt59 Cu41 octahedron shows much better catalytic activity, that is 34.84 m A cm^-2/5.58 A mg^-1 Pt for specific activity/mass activity, which is 9.16/7.34 times higher than commercial Pt black, respectively. In situ Fourier transform infrared spectroscopy is employed to detect the intermediate species and products for methanol/ethanol oxidation reaction and a plausible mechanism is proposed to explain the improved activity and durability of Pt59 Cu41 octahedron toward methanol/ethanol oxidation in alkaline medium.

The influence of temperature on the PLC effect in Al-Mg alloy

An experimental investigation of the influence of temperature on the Portevin-Le Chatelier(PLC) effect in Al-Mg alloy is conducted.Under a certain strain rate,the PLC effect is present in the temperature range of 223-328 K.The serration amplitude increases monotonically with increasing temperature,whereas the behaviors of the serration period and the critical strain with temperature include a descending branch under corresponding low temperature range and an ascending branch under corresponding high temperature range.The analysis in relation with dynamic strain aging(DSA) indicates that the temperature plays an important role in the PLC effect by dictating the solubility and the diffusibility of solute atoms.Both the concentration and the diffusibility of solute atoms contribute to increasing the serration amplitude.Under the descending branch temperature range,the serration period mainly depends on the preparation phase and the dominant factor of critical strain is the velocity of dislocations.However,under the ascending branch temperature range,the serration period mainly depends on the pinning phase and the dominant factor of critical strain is the applied stress required for unpinning.

Hole effective mass in strained Si (111)

The directional, averaged, and density-of-states effective masses of holes have been calculated for strained Si/(111)Si1-xGex. The results for the directional effective mass show that the effect of strain makes the constant energy surface of "heavy" holes more obvious warping than that in relaxed Si. The [111] and [110] directional effective masses of "heavy" holes decrease significantly under strain. It is found that the averaged effective mass of "heavy" holes decreases with increasing Ge fraction, while that of "light" holes increases. The traditional concepts of heavy and light holes become insignificant when Ge fraction is close to 0.4. The strain effect monotonically reduces the density-of-states effective mass at 218, 300 and 393 K, respectively.