新型可紫外光固化水性聚氨酯的制备与表征

以异佛尔酮二异氰酸酯(IPDI)、聚酯二元醇Pol-1256、二羟甲基丙酸(DMPA)为主要原料,采用预聚体法制备了水性聚氨酯预聚体,然后用自制的扩链剂对该预聚体进行扩链,并用丙烯酸羟乙酯(HEA)对扩链后的预聚体进行封端,最后中和乳化,制备了高紫外光(UV)固化基团含量的可UV固化水性聚氨酯乳液。采用FTIR对产物的结构进行了鉴定,利用旋转流变仪对分散体的流变性能进行了表征,通过TGA分析了UV固化膜的耐热性能,并对其拉伸性能进行了测试。研究结果表明:所制扩链剂符合预期结构特征,所得产物符合可UV固化的水性聚氨酯结构特征;乳液呈现出剪切变稀的特征,属于假塑性流体;UV固化膜具有良好的耐热性能,同时具有较高的断裂伸长率和良好的拉伸强度。     

基于PEDA的UV固化水性聚氨酯乳液及涂膜性能研究

目的研究双键含量可调的紫外光固化水性聚氨酯乳液及其涂膜性能。方法通过直接酯化法制备季戊四醇二丙烯酸酯(PEDA),并以其为功能性扩链剂与甲苯二异氰酸酯(TDI)、聚酯二元醇(POL-756T)、二羟甲基丙酸(DMPA)等原料制备一系列从侧基引入C=C双键的水性聚氨酯乳液。分别研究不同含量的PEDA及DMPA对乳液及涂膜性能的影响。结果 PEDA含量的增加会使其涂膜拉伸强度增加,断裂伸长率降低,热稳定性随之增强;DMPA含量的增加会使乳液的稳定性增强,颜色更加透明,粒径变小,但耐水性会降低。结论当PEDA质量分数为6.1%,DMPA为8.3%时,UV固化水性聚氨酯乳液具有良好的外观、稳定的性能,且涂膜的耐水性和力学性能优异。     

水性UV固化含氟聚氨酯树脂的制备及性能研究

以异佛尔酮二异氰酸酯(IPDI)、聚四亚甲基醚二醇(PTMG-1000)、2,2-二羟甲基丙酸(DMPA)、自制的含氟二醇及季戊四醇三丙烯酸酯(PETA)为原料,通过缩合聚合法合成一种新型水性UV固化含氟聚氨酯涂料树脂。利用FT-IR对树脂固化前后的分子结构进行表征。采用粒度分析、Zeta电位分析、接触角以及各种性能测试等手段,对其乳液、光固化过程及涂膜进行了分析研究。     

UV固化水性聚氨酯基油墨的制备

将季戊四醇三丙烯酸酯引入聚氨酯预聚体的末端,制备了新型可UV固化的水性聚氨酯树脂,并以其为连接料,制备了UV固化水性凹印油墨,研究了DMPA质量分数对UV固化水性聚氨酯乳液性能的影响及UV固化水性凹印油墨的性能。结果表明,随着DMPA质量分数的增加,乳液的颜色由乳白不透明逐渐转变为半透明泛蓝光,稳定性能增强,粒径不断减小,固含量随之增加,综合考虑,确定适宜的DMPA质量分数为6.25%;制得的UV固化水性凹印油墨符合国家标准的水性烟包凹印油墨的性能要求,基本能够满足实际使用过程中印刷适性的要求。     

蓖麻油酸基UV固化水性聚氨酯的合成及性能研究

以蓖麻油酸(RA)、六亚甲基二异氰酸酯三聚体(HDT)、聚乙二醇400(PEG-400)、季戊四醇三丙烯酸酯(PETA)和三乙胺(TEA)为主要原料,合成了具有哑铃结构的环保健康的高活性多烯端基水性UV固化聚氨酯预聚物。通过调节RA和PEG-400的相对含量制备出一系列不同羧基含量的树脂。并采用纳米粒度仪、光学接触角仪和电子拉力机等仪器对其结构、性能进行表征。结果表明:增加RA含量能使合成的乳液粒径小、分布窄、储存时间长,热稳定性好,透明度高,形成的涂膜具有一定的耐水性,较好的拉伸性能。     

二聚酸聚酯二醇基可紫外光固化水性聚氨酯的合成与性能

以异佛尔酮二异氰酸酯、二聚酸聚酯二醇（PDFA）、2,2-二羟甲基丙酸、1,4-丁二醇等为主要原料,采用季戊四醇二丙烯酸酯和丙烯酸羟乙酯分别在分子链的侧基和末端引入可UV固化的双键,制备出具有不同双键含量的可UV固化的水性聚氨酯PDFA-PU。红外光谱（FT-IR）分析证实了PDFA-PU的结构以及UV固化后双键的交联...     

氟改性UV固化水性星型聚氨酯的合成与性能研究

以全氟辛酸(PFOA)和2-氨基2-甲基-1,3丙二醇(AMPG)自制含氟长链的二元醇(FMPG),采用HDI三聚体(HDT)和二乙醇胺(DEOA)合成了六羟基多元醇(HDPO),采用异佛尔酮二异氰酸酯(IPDI)、聚碳酸酯二元醇(PCDL)、含氟二元醇(FMPG)、二羟甲基丙酸(DMPA)、季戊四醇三丙烯酸酯(PETA)和六羟基多元醇(HDPO)为主要原料合成了氟改性的UV固化水性星型聚氨酯(FWPU)。研究了FMPG含量对星型水性聚氨酯涂层材料性能的影响。结果表明：随着FMPG含量的增加，材料疏水性与耐水性会提高，涂层材料的耐热性也会得到进一步增强，当FMPG添加量在8%时对涂层材料的太阳光谱透过性能几乎没有影响，综合性能最佳。     

TMP/蔗糖改性鞋用水性聚氨酯胶粘剂的合成及性能表征

以聚乙二醇(PEG)、异佛尔酮二异氰酸酯(IPDI)为基料.三羟甲基丙烷(TMP)、蔗糖为交联剂改性制备水性聚氨酯胶粘剂.通过差示扫描量热(DSC)、凝胶渗透色谱(GPC)和激光粒度仪等考察了TMP含量对水性聚氨酯乳液和胶膜性能的影响,确定TMP在蔗糖体系中的最佳含量,并将制备的胶粘剂用于不同鞋材的粘接.结果表明,随着...     

TiO_2/石墨烯纳米复合材料对UV固化水性聚氨酯的改性EI北大核心CSCD

通过溶胶-凝胶法制备了锐钛矿型的纳米TiO_2,用改进的Hummers法制备了氧化石墨烯,用水热法合成了纳米TiO_2/石墨烯复合材料。采用异佛尔酮二异氰酸酯和聚乙二醇1000为反应单体,二月桂酸二丁基锡为催化剂,二羟甲基丙酸作为扩链剂,并以甲基丙烯酸羟乙酯封端,成功制备出水性聚氨酯预聚体。将TiO_2/石墨烯复合材料引入UV固化聚氨酯体系,制备了含有不同质量分数复合材料的聚氨酯涂层。采用扫描电子显微镜、X射线粉末衍射、傅里叶变换红外光谱、紫外-可见分光光度计等手段对样品进行表征,分析了材料的形貌、组成、结构及光催化降解性能。结果表明,TiO_2/石墨烯复合材料改性水性聚氨酯涂料表现出了较好的光催化性能。280nm紫外光照射下24h之内对甲基橙降解率达到77.20%,而在可见光条件下复合材料对甲基橙降解率达到57.52%。经改性的聚氨酯涂层的各项力学性能有了不同程度的提高。     

光固化聚氨酯-丙烯酸酯乳液的制备及对纸张的增强作用

以异佛尔酮二异氰酸酯(IPDI)、聚己内酯二元醇(PCL1000)、二羟甲基丁酸(DMBA)、季戊四醇三丙烯酸酯(PETA)和丙酮等为原料合成了水性光固化聚氨酯-丙烯酸酯复合乳液,并利用该乳液对纸张进行表面施胶。通过傅立叶红外光谱(FT-IR)和光散射对乳液的结构进行了分析;研究了n(NCO)/n(OH)比值(R值)对乳液和涂膜耐水性和力学性能的影响,紫外光(UV)固化前后对纸张物理性能的影响。结果表明,当n(NCO)/n(OH)=1.6,m(PETA)=12.6%时,乳液具有良好的稳定性,涂膜呈现良好的耐水性和力学强度,吸水率降至3.66%;UV固化后纸张湿强度提高41.65%,纸张环压指数达到5.25N.m/g。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...