加强综合素质培养 提高就业竞争能力

大学毕业生就业需要广博扎实的专业知识和各种各样的能力。长文主要结合近年来大学生就业、从业的实际情况以及用人单位的反馈意见来阐述:提高大学生就业竞争的几种基本能力,以帮助大学生在未来求职中及时调整自己、完善自己。

Preparation and properties of novel Cu-based bulk metallic glasses Cu_(55-x)Zr_(37)Ti_8In_x

The glassy rods were successfully fabricated in the Cu-Zr-Ti-In alloy system by casting into a copper mold. The value of ATx reaches a maximum of 66 K for the BMG CusoZraTTi8In5 alloy. The reasons for enhancing glass forming ability of Cu-based BMGs with the addition of indium were discussed from atomic size and thermodynamics. Alternatively, the BMG Cu52Zra7Ti8In3 exhibits the highest compressive strength （1981 MPa） and the best plasticity among glassy Cu55-xZra7TisInx （x_〈5）. The total plastic deformation of Cu52Zr37TisIn3 before fracture approaches 1.2%.

Effect of heat treatment on microstructure, mechanical properties and in vitro degradation behavior of as-extruded Mg-2.7Nd-0.2Zn-0.4Zr alloy

Mg-2.7Nd-0.2Zn-0.4Zr （mass fraction, %） alloy was designed for degradable biomedical material. The ingots of the alloy were solution treated and then hot extruded. The extruded rods were heat treated with aging treatment, solution treatment and solution＋aging treatment, respectively. Microstructures of the alloy were observed by optical microscopy （OM） and scanning electron microscopy （SEM）. Mechanical properties at room temperature were tested. In vitro degradation behavior of the alloy immersed in simulated body fluid was measured by hydrogen evolution and mass loss tests. The degradation morphologies of the alloy with and without degradation products were observed by SEM. The results show that the grains grow apparently after solution treatment. Solution treatment improves the elongation of as-extruded alloy significantly and decreases the strength, while aging treatment improves the strength and reduces the elongation of the alloy. The yield ratio is reduced by heat treatment. The in vitro degradation results of the alloy show that solution treatment on the as-extruded alloy results in a little higher degradation rate and aging treatment on the alloy can reduce degradation rate slightly.

制造企业服务化转型的海星模式研究

卓越服务绩效来源于服务战略的顶层设计与有效实施。杭氧集团和陕鼓集团案例表明,"海星模式"在推动制造企业服务化转型方面效果显著。"海星模式"的运作机理是,企业首先通过内部培养、战略联盟或并购方式,打造服务能力集合体,以此作为向外延伸服务触角的能力平台。在服务需求强劲领域中生成新的服务触角,每个服务触角都有独特商业模式来支撑,并在目标市场中快速复制,以实现服务业的规模经济。服务能力集合体与各服务触角间的知识流动,使得各服务业务享受"同一屋檐"下的好处,从而产生经验经济。研究显示,服务业务的规模经济与经验经济互动强化,形成"海星模式"成功的战略逻辑。

Microstructure control and mechanical properties of directionally solidified TiAl-Nb alloys

The double directional solidification（DS） technique was developed to control the lamellar microstructures in primary β TiAl-Nb alloys.Polysynthetically twinned（PST） crystals with lamellar boundaries parallel to or inclined 45o to the growth direction were achieved due to the complete peritectic transformation during directional solidification of the alloys with the dendritic solid/liquid interface.The PST crystals with aligned lamellar boundaries only parallel to the growth direction were produced when lamellar grains with lamellar boundaries in the same orientation were seeded by themselves under appropriate growth conditions.Low boron addition is harmful to align the lamellar orientation because of the growth of non-peritectic α phase.Due to the larger yttria particles and boride ribbons in the directionally solidified TiAl-Nb alloys,the tensile plastic elongations of the alloys are only close to 2%.

THE STRUCTURE DESIGN AND THE DYNAMIC ANALYSIS OF THE MAGNETIZATION MECHANISM OF THE COLLECTOR OF MACHINING WASTE

This paper presents the structural design and dynamic analysis of the magnetic field of the collector of machining wastes. From the viewpoint of energy the magnetic coupled force exerted on machining wastes by the nonuniform magnetic field of a permanent magnet has been discussed. The difficult problem that machining wastes attracted by a permanent magnet above the iron base platform has been solved.

Effect of complex melt-refining treatment on microstructure and mechanical properties of sand-cast Mg–10Gd–3Y–0.5Zr alloy

The effect of complex melt-refining treatment （melt flux incorporating with rotating gas bubble stirring） on microstructure and mechanical behavior of the sand-cast Mg-10Gd-3Y-0.5Zr alloy was investigated. In addition, the melt purifying mechanism of the complex melt-refining treatment for the sand-cast alloy was discussed systematically. The results show that the new melt-refining method can significantly improve melt quality and mechanical behavior of the tested alloy, i.e., compared to the reference unpttdfied alloy, the volume fraction of inclusions decreased from 0.47% to 0.28%, the ultimate tensile strength and elongation for T6-treated alloy increased from 245 MPa and 0.7% to 312 MPa and 4.5%, respectively. Especially, combining 1% flux with rotating gas bubble stirring can get even better purifying effectiveness than conventional sole 2% flux purification; the use of melt flux decreased by 50% and significantly reduced environmental pollution.

Microstructure,mechanical properties and corrosion behavior of Al-Si-Cu-Zn-X(X=Bi,Sb,Sr) die cast alloy

The microstructure evolution, mechanical and corrosion properties of Al-11Si-2Cu-0.8Zn die cast alloy treated with Bi, Sb and Sr additions were investigated. The results of mechanical testing showed that all additions increased impact toughness, ultimate tensile strength, and elongation of the alloy as a result of change in eutectic Si morphology. The analysis of fracture surfaces revealed that with addition of Sr and to lesser extent Bi and Sb, the alloy exhibited a predominantly ductile fracture rather than quasi-cleavage brittle fracture. Moreover, with the additions of Sr, Bi and Sb, the quality index increased to 164.7 MPa, 156.3 MPa and 152.6 MPa respectively from 102 MPa for the base alloy. Polarization corrosion tests conducted in sodium chloride solution showed that the corrosion potential shifted to more negative values with additions of Sb, Bi and Sr, respectively. Corrosion immersion tests also revealed that the element additions have a detrimental effect on the corrosion rate of alloys, due to the increase of boundaries between the Al and eutectic Si phases.

Effects of solution-aging treatment on microstructures and properties of Ti-55.06%Ni-0.3%Cr alloy

The effects of solution-aging treatment on the microstructures, mechanical properties and internal friction of Ti- 55.06%Ni-0.3%Cr （mole fraction） alloy were investigated by means of tensile test, dynamic mechanical analysis （DMA） and spherical aberration electron microscopy （SAEM）. The results show that the aged alloys with Cr3Ni2 phase always exhibit higher tensile strength and hardness than those of solution-treated alloy without Cr3Ni2 phase, and the aging peak temperature presents at 375 ℃. It is also found that the internal friction peak （tan 6） value decreases with increasing the frequency. There are two internal friction peaks corresponding to the B2（austenite）→R and R→M（martensite） transformations upon cooling, but only one corresponding to the reverse M→B2 transformation upon heating in both solution-treated and 375 ℃-aged alloys, due to the superposition of Mand R phase transformation. Besides, the position of internal friction peaks in the alloy after aging at 375 ℃ shifts to higher temperature. This is attributed to the decrease of Cr and Ni content, and the decline of lattice deformation and transformation resistance, all of which are related to the precipitation of Cr3Ni2 phase in the solution-aged alloys.

Effect of Structural Parameters on the Performance of NS High-efficiency Composite TraysⅠ.The Effect of Aperture and Opening Ratio on NS High-efficiency Composite Trays

In this paper,the structure and characteristics of the NS high-efficiency composite trays based on the doublelayer aperture jet sieve plate and compositely structured packing were investigated.The effect of aperture and opening ratio of plate on the fluid dynamics of the NS high-efficiency composite trays,such as the dry tray pressure drop,the wet tray pressure drop,the entrainment,the froth height,the leakage and mass transfer characteristics,were investigated.As a result, the low pressure drop,the high efficiency and the high capacity are the main advantages of the NS high-efficiency composite trays compared to other types of trays.According to this study,small aperture is useful for reducing the pressure drop and entrainment with a high mass transfer efficiency;while large aperture can achieve high capacity and efficiency in a broader operating range at the same pressure drop and entrainment.

Children and adolescents with Down syndrome,physical fitness and physical activity

Children(5-12 years) and adolescents(13-19 years) with Down syndrome(DS) possess a set of health,anatomical,physiological, cognitive,and psycho-social attributes predisposing them to limitations on their physical fitness and physical activity(PA) capacities.The paucity of studies and their conflicting findings prevent a clear understanding and/or substantiation of these limitations.The purpose of this article was to review the measurement,determinants and promotion of physical fitness and PA for youth(i.e.,children and adolescents) with DS. The existing body of research indicates that youth with DS:1) have low cardiovascular and muscular fitness/exercise capacity;2) demonstrate a greater prevalence of overweight and obesity;3) a large proportion do not meet the recommended amount of daily aerobic activity;and 4) their PA likely declines through childhood and into adolescence.Future research should focus on:1) strength testing and training protocols;2) methodologies to determine PA levels;and 3) practical interventions to increase PA.

Improvement of chromium biosorption through protoplast electrofusion between Candida tropicalis and Candida lipolytica

Protoplasts from Candida tropicalis and Candida lipolytica were fused under an optimized electrofusion （electrical pulse strength 6 kV/cm, pulse duration time 40μs and pulse times 5） and then regenerated on YEPD media for achieving new genotypes with higher chromium loading capacity. A target fusant RHJ-004 was screened out by its chromium resistance and chromium-sorbing capacity tests for further research. The comparative study of applicability shows that the fusant has better performance than its parent strains in respect of solution pH, biomass concentration and chromium loading capacity. Especially for treating low concentration Cr（VI） （〈20 mg/L）, above 80% chromium is sequestered from the aqueous phase at pH 1-9. Atomic force microscopy （AFM） visualizes the distribution of chromium on the binding sites of the cells, suggesting that the altered surface structure and intracellular constitutes of the fusant associate with its increased biosorption capacity. The rapid biosorption processes of chromium foUow the Langmuir model well.

Effects of Sr addition on microstructure, mechanical properties and in vitro degradation behavior of as-extruded Zn-Sr binary alloys

The microstructures,mechanical properties and in vitro degradation behavior of as-extruded pure Zn and Zn-x Sr(x=0.1,0.4,0.8 wt.%)alloys were investigated systematically.For the microstructure and mechanical properties,Sr Zn13 phase was newly formed due to the addition of 0.1 wt.%Sr,improving the yield strength,ultimate tensile strength and elongation from(85.33±2.86)MPa,(106.00±1.41)MPa and(15.37±0.57)%for pure Zn to(107.67±2.05)MPa,(115.67±2.52)MPa and(20.80±2.19)%for Zn-0.1Sr,respectively.However,further increase of Sr content led to the deterioration of the mechanical properties due to the stress concentration and cracks initiation caused by the coarsening Sr Zn13 particles during tensile tests.For in vitro degradation,since micro galvanic corrosion was enhanced owing to the formation of the inhomogeneously distributed Sr Zn13 phase,the corrosion mode became non-uniform.Corrosion rate is gradually increased with the addition of Sr,which is increased from(11.45±2.02)μm/a(a=year)for pure Zn to(32.59±3.40)μm/a for Zn-0.8Sr.To sum up,the as-extruded Zn-0.1Sr alloy exhibited the best combination of mechanical properties and degradation behavior.

Microstructure, martensitic transformation and mechanical properties of Ni-Mn-Sn alloys by substituting Fe for Ni

The effects of partial substitution of Fe element for Ni element on the structure,martensitic transformation and mechanicalproperties of Ni50-xFexMn38Sn12(x=0and3%,molar fraction)ferromagnetic shape memory alloys were investigated.Experimentalresults indicate that by substitution of Fe for Ni,the microstructure and crystal structure of the alloys change at room temperature.Compared with Ni50Mn38Sn12alloy,the martensitic transformation starting temperature of Ni47Fe3Mn38Sn12alloy is decreased by32.5K.It is also found that martensitic transformation occurs over a broad temperature window from288.9to352.2K.It is found that themechanical properties of Ni-Mn-Sn alloy can be significantly improved by Fe addition.The Ni47Fe3Mn38Sn12alloy achieves amaximum compressive strength of855MPa with a fracture strain of11%.Moreover,the mechanism of the mechanical propertyimprovement is clarified.Fe doping changes the fracture type from intergranular fracture of Ni50Mn38Sn12alloy to transgranularcleavage fracture of Ni47Fe3Mn38Sn12alloys.

Research on the Interactive Interpreting Teaching Mode under the Multimedia and Traditional Microteaching Environment

In this paper, we conduct research on the interactive interpreting teaching mode under the multimedia and primary traditional microteaching environment. English interpretation course system construction request from the student reality, on the basis of the actual situation, improving students＇ comprehensive ability in English interpretation as communicative teaching method in the very great degree to overall effective guide students to practice real interpreting scene comprehensively improve students＇ intercultural business negotiation, reception and comprehensive ability of the exhibition, and is advantageous to the interpretation of curriculum system construction and the improvement of the students＇ comprehensive quality. Our research integrates the general principles of the multimedia and primary traditional microteaching environment to form the better paradigm for the education that will enhance the contemporary teaching condition.

GA-SVC model and application of comprehensive evaluation of coal mine essential safety management

In order to evaluate the level of the coal mine essential safety management, the comprehensive index system was designed base on the connotation principle of the mine essential safety management. Due to the disadvantage of index weight setting by subjective idea in the former method, support vector classification algorithm was used to assess the level of coal mine essential safety management. According to the advantages of the global search capability of the genetic algorithm, support vector classification parameters optimization method was proposed based on genetic algorithm, and genetic algorithm-support vector classification model of coal mine essential safety management assessment was established. Learning samples were constructed on the basis of former data of mine essential safety management evaluation. The test results show that the genetic algorithm-support vector classification model has higher evaluation accuracy and good generalization ability, and the advantage of no need for artificial setting of index weight and absence of the subjective factors influence to evaluation results.

Recent advances in the molecular genetics of resin biosynthesis and genetic engineering strategies to improve defenses in conifers

Since the first terpenoid synthase cDNA was obtained by the reverse genetic approach from grand fir, great progress in the molecular genetics of terpenoid formation has been made with angiosperms and genes encoding a monoterpene synthase, a sesquiterpene synthase, and a diterpene synthase. Tree killing bark beetles and their vectored fungal pathogens are the most destructive agents of conifer forests worldwide. Conifers defend against attack by the constitutive and inducible production of oleoresin that accumulates at the wound site to kill invaders and both flush and seal the injury. Although toxic to the bark beetle and fungal pathogen, oleoresin also plays a central role in the chemical ecology of these boring insects. Recent advances in the molecular genetics of terpenoid biosynthesis provide evidence for the evolutionary origins of oleoresin and permit consideration of genetic engineering strategies to improve conifer defenses as a component of modern forest biotechnology. This review described enzymes of resin biosynthesis, structural feathers of genes genomic intron and exon organization, pathway organization and evolution, resin production and accumulation, interactions between conifer and bark beetle, and engineering strategies to improve conifer defenses.

Mechanical Design and Students＇ Creativity ＂Think outside the Box＂

A design project was used in junior level mechanical design course to challenge the students＇ creativity skills. Beside the theoretical foundation of the course subject, the students were introduced to several professional skills such as： decision making tools, technical review meetings, interaction with customers, and teamwork skills. The design challenge was to develop a bike rack to meet a list of technical and marketing constraints. Details of the project requirements are presented with a brief overview of the main project mentoring tools. Students＇ creativity is discussed through two samples of the student work. It was noticed that, the basic creativity skills of the students can be improved by using some of the training tools, however, the students vary in their response to this training.

灵长类原始态多能干细胞的研究与挑战

啮齿类和传统的灵长类多能干细胞(pluripotent stem cells,PSCs)在很多方面表现出不同的属性.根据发育阶段、克隆形态、信号依赖、线粒体代谢、嵌合能力、基因表达以及表观遗传等差异,哺乳动物干细胞多能性被分为原始态(Naive)和始发态(Primed)两种状态.啮齿类PSCs表现为Naive特性,而小鼠外胚层干细胞(epiblast stem cells,Epi SCs)和传统的灵长类PSCs表现为Primed特性.体外是否存在灵长类Naive PSCs是当前干细胞研究的一个关键性科学问题,开展非人灵长类PSCs的研究对于解决该问题起到至关重要的作用.最近几项研究通过各自的方法获得了不同的灵长类Naive-like PSCs,这些细胞在很多方面表现出类似于啮齿类PSCs的Naive特性.本文分析了啮齿类和灵长类胚胎发育差异性产生不同PSCs的可能机制,总结了本研究组和其他研究小组在灵长类干细胞多能性方面的研究进展以及原始态(Naive)和始发态(Primed)PSCs自我更新的调控机制差异最后,对灵长类干细胞多能性研究存在的问题进行了分析,对将来的研究重点进行了展望.

New quantum matters:Build up versus high pressure tuning

In this article we briefly review new quantum functional compounds primarily based on our recent works. We will highlight the effects of pressures on both materials synthesis and quantum tuning. The contents include （I） ＂111＂-type iron based super- conducting system, （II） pressure induced superconductivity in topological insulators and （II/） the new diluted magnetic semi- conductors with decoupled spin charge doping.