防尘卸料的箱形散貨卸船机

采用抓斗式起重机进行散货卸船,存在着一定的缺点。本文介绍了一种新设计的箱形散货卸船机的试验过程、操作工艺、主要参数的计算方法及其经济比较。1.概述世界上所有的港口,除了极个别的以外,     

圣戈班邀您免费游埃菲尔铁塔 圣戈班集团成立350周年微信活动即将推出

正1665年,当Colbert创立皇家玻璃工坊并承建巴黎凡尔赛宫镜廊的357块玻璃,未知其是否料想到,自己将成为一段长达数个世纪的长盛传奇的开路人。在迎来企业350周年的今日,当初那个名为"圣戈班"的作坊已经成长成为全球最强大、最具影响力的企业之一,而传奇,仍在继续!埃菲尔铁塔:世界建筑史上的技术杰作埃菲尔铁塔(法语:La Tour Eiffel)矗立在法国巴黎的战神广场,是世界著名建筑,也是法国文化象征之一,巴黎城市地标之一,也是巴黎最高建筑物,高300米,天线高24米,总高324米,于1889年建成,得名于设计它的著名建筑师、结构工程师古斯塔夫·埃菲尔。铁塔设计新颖独特,既是世界建筑史上的技术杰作,也是19世纪工业革命的象征,一直到1 930年始终是全世界最高的建筑。1887年1月28日,埃菲尔铁塔正式开工,1889年3月31日     

塑料等价格上涨将致汽车原材料成本上扬10%

<正>IRN咨询公司近日对82家汽车生产商的调查显示,近半车厂预计,明年汽车原材料成本将上涨10%,其中钢铁和塑料的价格上涨可能性最大。在6月16日公布的这份调查结果中,64%受访对象预计,塑料的价格将上扬,而只有4%的受访对象预计塑料的价格将会有所回落。     

Microstructural Development of Ti-B Alloyed Layer for Hard Tissue Applications

Microstructural development was analyzed due to the effect of different sizes of precursor powders during surface plasma alloying modification on titanium surface.Ti-B nano and micropowders with 10 wt%B were deposited onto microcrystalline titanium substrate by plasma alloying.As a result,modified surface layer composed of Ti matrix and TiB borides was obtained.The type of the powder precursor influenced recasting process,possible occurrence of porosity and finally the obtained properties and microstructure of the surface layer.Different morphologies and sizes of TiB phase from micro,submicro to even nano increased the hardness and wear resistance of the obtained surface layers.Discussed results referred to a strong TiB precipitation dispersion provided by a fine elements homogenization during mechanical alloying process. Additionally,results of in vitro test with normal human osteoblast cells revealed proper cellular adhesion to modified surfaces.Scanning electron microscopy observation revealed the influence of gas pore size on culturing osteoblast colony.The proposed surface alloying was an effective method of producing TiB phase dispersed inα-Ti matrix with high hardness,good corrosion resistance and good cytocompatibility.Results confirmed that different types of the precursor powders influenced the properties of the surface layer.TiB phase dispersed inα-Ti matrix layer can offer new structural and biofunctional properties for innovative products in hard tissue applications.     

Isotropic and anisotropic dipeptide films based on gas phase deposition

We demonstrated the fabrication and application of well-ordered and vertically aligned dipeptide nanostructures based on a simple gas phase deposition. Deposited nanostructures exhibited the superhydrophobic property with a very low sliding angle. Highly reproducible SERS data have also been obtained after combining deposited films with a thin layer of gold. In addition to these, directional peptide films were, for the first time, successfully fabricated based on the oblique angle deposition technique. We believe that such bio-inspired materials would have a great impact in several technological applications involving catalysis, tissue engineering and biosensors.     

关于高校计算机科学教育的实践研究

作为一项实用性很强的专业技能课,计算机科学教育在现阶段高校的教学当中的地位日显重要.本文结合实际教学,对高校的计算机教育进行阐述和分析,并针对教育过程中所出现的问题,研究出解决途径.     

Low-Oxidation State Indium-Catalyzed C-C Bond Formation

The development of innovative metal catalysis for selective bond formation is an important task in organic chemistry. The group 13 metal indium is appealing for catalysis because indium-based reagents are minimally toxic, selective, and tolerant toward various functional groups. Among elements in this group, the most stable oxidation state is typically +3, but in molecules with larger group 13 atoms, the chemistry of the +1 oxidation state is also important. The use of indium(III) compounds in organic synthesis has been well-established as Lewis acid catalysts including asymmetric versions thereof. In contrast, only sporadic examples of the use of indium(I) as a stoichiometric reagent have been reported: to the best of our knowledge, our investigations represent the first synthetic method that uses a catalytic amount of indium(I). Depending on the nature of the ligand or the counteranion to which it is coordinated, indium(I) can act as both a Lewis acid and a Lewis base because it has both vacant p orbitals and a lone pair of electrons. This potential ambiphilicity may offer unique reactivity and unusual selectivity in synthesis and may have significant implications for catalysis, particularly for dual catalytic processes. We envisioned that indium(I) could be employed as a metallic Lewis base catalyst to activate Lewis acidic boron-based pronucleophiles for selective bond formation with suitable electrophiles. Alternatively, indium(I) could serve as an ambiphilic catalyst that activates both reagents at a single center. In this Account, we describe the development of low-oxidation state indium catalysts for carbon-carbon bond formation between boron-based pronucleophiles and various electrophiles. We discovered that indium(I) iodide was an excellent catalyst for α-selective allylations of C(sp(2)) electrophiles such as ketones and hydrazones. Using a combination of this low-oxidation state indium compound and a chiral semicorrin ligand, we developed catalytic highly enantioselective allylation, crotylation, and α-chloroallylation reactions of hydrazones. These transformations proceeded with rare constitutional selectivities and remarkable diastereoselectivities. Furthermore, indium(I) triflate served as the most effective catalyst for allylations and propargylations of C(sp(3)) electrophiles such as O,O-acetals, N,O-aminals, and ethers, and we applied this methodology to carbohydrate chemistry. In addition, a catalyst system composed of indium(I) chloride and a chiral silver BINOL-phosphate facilitated the highly enantioselective allylation and allenylation of N,O-aminals. Overall, these discoveries demonstrate the versatility, efficiency, and sensitivity of low-oxidation state indium catalysts in organic synthesis.     

苏联的萌系铁兽——T-24中型坦克

2013年春节前夕,笔者闲逛模型店,被T-24坦克模型的呆萌外形所吸引,开盒简单地看了板件和说明书后,我就毅然将这个萌系铁兽买回了家,原因就是板件少,春节期间悠闲地做做模型,真是乐事一件。回到家后,我便立刻开始了制作。这款苏联T-24中型坦克由Hobby Boss出品,编号82493。     

养犬须知三 如何养好一只幼犬!

正你是它的爸爸妈妈,也是它的朋友,更是它的保姆老师。它会不会成为一个懂事的淑女绅士,完全看你的努力,天使恶魔就在你一念之间。养狗前,我们很有必要简单了解一下它的习性和需求。当它踏入你的生活之前,你有些要准备的东西。这里我列了一份简易清单,包括围栏、狗厕所、尿垫、大的浴巾、饮水头、食盆、狗窝、玩具等,这样我们聊起来会更顺畅一些。