硅碳复合结构对锂离子电池负极电化学性能的影响

以晶硅太阳能电池生产过程中的晶硅切削废料为原料、以壳聚糖(Chitosan, CTS)为碳源,通过液相包裹和低温热解工艺制备了具有较大孔隙的硅/硬碳复合材料(Si@CTS).对比研究了Si@CTS及Si@CTS混合石墨后(Si@CTS/G)分别作为锂离子电池负极的电化学性能.结果表明,具有孔隙和互联结构的Si@CTS负极首次放电比容量可达到1 672.8 mAh/g,首次库伦效率达到了84.45%;在循环100圈之后Si@CTS放电比容量保持在626.4 mAh/g.进一步,将Si@CTS作为高容量活性物质添加至石墨中,研磨混合后制得的Si@CTS/G复合负极表现出良好的稳定性,在循环100圈之后放电比容量为698.1 mAh/g,对高容量高稳定性硅碳负极批量化生产和应用具有重要意义.     

The effect of Fe on the martensitic transformation of TaRu high-temperature shape memory alloys:A first-principles study

The effect of Fe on the martensitic transformation of TaRu high-temperature shape memory alloys has been investigated using first-principles calculations. The site preference of Fe in TaRu alloys has been clarified for the first time, and the results show that Fe is predicted to occupy Ru sites. The addition of Fe increases the stability of the Ta₅₀Ru_50-xFe_x β phase, leading to a significant decrease in the β to β′ martensitic transformation temperature. In addition, the mechanism of the Fe alloying effect is explained on the basis of the electronic structure.     

First-principles study on the effect of Hf content onmartensitic transformation temperatureof TiNiHf alloy

In this paper a first-principles study of the electronic structure and stability of B2 TiDFT TiNiHf 电子结构 马氏体转化温度 平面波DFT, TiNiHf, electronic structure, martensitic transformation temperatureProject supported by the National Natural Science Foundation of China (Grant No 50471018).3/3/2006 12:00:00 AM6/7/2006 12:00:00 AMIn this paper a first-principles study of the electronic structure and stability of B2 Ti1-xNiHfx （x = 0.2, 0.4, 0.6） and B19′ Ti1-xNiHfx（x = 0, 0.5） alloys is presented. The calculations are performed by the plane-wave pseudopotential method in the framework of the density functional theory with the generalized gradient approximation. This paper calculates the lattice parameters, density of states, charge density, and heats of formation. The results show that the electronic structure and stability of B2 Ti1-xNiHfx change gradually with Hf content. However, Hf content has little effect on the electronic structure and stability of B19′ Ti1-xNiHfx. The mechanism of the effect of Hf content on martensitic transformation temperature of TiNiHf alloys is studied from the electronic structure.     

基于激光散透比的牛乳脂肪测试技术研究

依据光散射原理,建立了利用散透比测量牛乳脂肪质量含量的理论模型,提出了牛乳脂肪质量含量的快速高准确度测量方法。实验结果表明,本方法能准确、快速的测量牛乳脂肪质量含量。     

潍坊会展旅游发展研究

会展旅游经济在区域和城市经济发展中具有重要的作用。它不仅可以促进和带动相关产业的发展,而且能够推动地区社会发展水平及人们精神风貌和素质的提高。文章分析了潍坊发展会展旅游经济的优势和劣势,对潍坊市会展旅游的发展和管理提出了几点建议和对策。     

Combined experimental and theoretical study on the effect of Nb content on martensitic transformation of NbRu shape memory alloys

The effect of Nb content on the martensitic transformation of NbRu high-temperature shape memory alloys is investigated by experiments and first-principles calculations. We calculate the lattice parameters, density of states, charge density, and heats of formation of Nb_50+xRu_50-x β phase. The results show that an increase in Nb content increases the stability of Nb_50+xRu_50-x β phase, leading to a significant decrease of the β to β' martensitic transformation temperature. In addition, the mechanism of the effects of Nb content on phase stability and martensitic transformation temperature is studied on the basis of electronic structure.     

基于超效率SBM模型的黄河中下游生态效率测度与空间相关性分析

以黄河中下游54个市域为研究对象,运用基于非期望产出的超效率SBM模型(Super-SBM Model)、空间自相关模型等方法,研究了2010—2019年黄河中下游生态效率的时空演变格局,并分析了黄河中下游生态效率的空间相关性。结果表明：(1)黄河中下游生态效率总体上处于较低水平,且年度间和市域间生态效率差异显著。(2)2010—2019年黄河中下游的生态效率评价值在时间维度上呈现“升-降-升”的演变趋势,空间上呈现东部、西部地区两端生态效率较高,中北部地区生态效率较低的格局。(3)黄河中下游地区生态效率在空间上全局自相关特征显著,局部空间关联集聚特征不显著。黄河中下游市域生态效率的Moran’s I值呈现“先减后增再减”趋势,空间依赖性先减弱后增加再减弱。     

温度和均质压力对牛乳蛋白质测试影响研究

研究了温度及均质压力对光学散透比法快速测量牛乳蛋白质质量含量的影响。实验结果表明,温度和均质压力对测量准确度有显著影响。通过对比实验确定了最佳的测试温度和压力。     

Effect of Co on magnetic property and phase stability of Ni--Mn--Ga ferromagnetic shape memory alloys: A first-principles study

The effect of Co content on magnetic property and phase stability of Ni50-xMn25Ga25Cox ferromagnetic shape memory alloys has been investigated using first-principles calculations. The total energy difference between paramagnetic and ferromagnetic state of austenite plays an important role in the magnetic transition. The high Curie temperature can be attributed to the stronger Co-Mn exchange interaction as compared to the Ni-Mn one. The phase stability of Ni50-xMn25Ga25Cox austenite increases with increasing Co content, which is discussed based on the electronic structure.     

如何对饭店核心员工有效激励

近年来,在饭店业迅速发展的过程中,饭店核心员工起了举足轻重的作用,但多数饭店在管理上缺乏对核心员工有效激励,以致无法调动他们的积极性,甚至影响饭店声望和士气,导致职业链条的中断等。本文在深入分析饭店核心员工内涵和特征的基础上,有针对性地提出有效激励和管理的措施和方法。