明胶接枝共聚制备高吸水性树脂的研究

采用明胶与丙烯酸(钾)接枝共聚制备高吸水性树脂,并考察了引发剂、交联剂、明胶的用量及丙烯酸中和度、单体质量分数等各因素对产物吸(盐)水倍率的影响;所得的高吸水性树脂的吸水倍率为535.3g/g,吸盐水倍率为53.8g/g,其吸(盐)水倍率较好,且在较低温度下的保水性也较好.     

微波辐射下利用天然废弃材料制备高吸水性树脂

利用天然废弃物野山杏肉为原料,采用微波辐射技术,以过硫酸铵为引发荆,N,N-亚甲基双丙烯酰胺为交联剂合成了一种野山杏肉接枝聚合丙烯酸/丙烯酰胺(AA/AM)的高吸水性树脂.并采用单因素实验与正交实验相结合的实验方法对其合成工艺进行了研究.合成了吸水倍率为802g/g,吸生理盐水倍率为75g/g的高吸水性树脂,并应用红外、扫描电镜、热重分析对其结构进行了表证.     

FP-g-P(AA-co-AM)高吸水树脂的制备

研究了鱼蛋白(FP)接枝聚合丙烯酸(AA)和丙烯酰胺(AM)制备蛋白改性高吸水性树脂的方法.通过对产品吸(盐)水性能的测试,得到合成产品的合适条件为:鱼蛋白、引发剂和交联剂相对单体的量分别约为7.5%、1.0%和0.025%,丙烯酸与丙烯酰胺的质量比为9:1,丙烯酸中和度为90%,单体质量分数为18%.在此条件下制备的高吸水性树脂,其吸水倍率达1061g/g,吸盐水倍率达136g/g.并用红外光谱对产物进行了表征.     

耐盐型壳聚糖高吸水树脂的制备及其性能

以天然无毒、可降解性、抑菌性能良好的壳聚糖(CS)为基体,利用自由基接枝聚合法接枝丙烯酸(AA)和2-甲基丙烯酰胺基-2-甲基丙磺酸单体(AMPS),制备了吸水性和耐盐性能良好的CS高吸水树脂。研究了各因素(温度、投料比、引发剂用量和交联剂用量等)对吸水性及耐盐性的影响,并用红外光谱及扫描电镜对高吸水树脂的结构和形貌进行表征。结果表明:在温度60℃、物料比m(CS)∶m(AA)∶m(AMPS)=1∶8∶3、交联剂用量及引发剂用量均为单体质量1%的条件下,合成的高吸水树脂最大吸水率达578.7g/g,吸盐率达114.2g/g;1h基本达到吸水平衡,且重复使用5次后,吸水率变化不大,重复使用性能良好。     

氧化石墨烯改性聚(丙烯酸/丙烯酰胺)高吸水树脂的制备及性能研究

为得到综合性能较优的高吸水性树脂,研究了氧化石墨烯(GO)对聚(丙烯酸/丙烯酰胺)[P(AA/AM)]高吸水树脂的改性作用。首先通过Hummers法制备了GO,采用水溶液合成法合成了P(AA/AM)-GO高吸水树脂,采用SEM、FT-IR、TGR等手段分析了改性高吸水树脂的微观结构及热性能,并对其进行了溶胀测试和保水性能测试;研究了GO质量浓度、单体配比、交联剂用量、引发剂用量等因素对P(AA/AM)-GO的耐盐性、吸水性的影响。结果表明,GO改性P(AA/AM)后,所得树脂的吸水倍率(QW)和吸盐水倍率(QS)分别为502g/g和122g/g,与市场上广泛使用的P(AA/AM)相比,耐盐性提高了2.8倍,热稳定性提高了58%,在100℃失水60min时保水率提高了21.5%。所以GO的加入能有效改善传统高吸水树脂的综合性能,同时拓宽了GO的应用领域。     

耐盐性魔芋葡甘聚糖吸水树脂的制备

以魔芋葡甘聚糖(KGM)为原料接枝丙烯酰胺、丙烯酸制备耐盐性吸水树脂,研究了接枝共聚反应单体及KGM质量配比、中和度、交联剂浓度、引发剂浓度、乙二胺四乙酸(EDTA)质量分数对吸水树脂吸液倍率的影响,通过Box-Behnken实验设计对制备条件进行优化。结果表明,丙烯酰胺与丙烯酸质量比为0.192,交联剂浓度为0.067g/mol,引发剂浓度为0.439g/mol,中和度为90%,乙二胺四乙酸(EDTA)质量分数为12.2%时,该耐盐性树脂吸生理盐水倍率达125g/g,吸纯水倍率达700g/g。     

敞开体系快速水溶液聚合法合成高吸水性树脂的研究

对丙烯酸(AA)、丙烯酰胺(AM)的水溶液聚合反应进行了研究,合成了高吸水性树脂,探讨了中和度、单体配比、交联剂用量、引发剂用量、水浴温度等对高吸水性树脂吸液倍率的影响,并用红外光谱对产物的结构进行了表征.5min合成的高吸水性树脂吸水倍率高达1600g·g-1,在质量分数为0.9%的食盐水中的吸液倍率达155g·g-...     

明胶接枝共聚丙烯酸铵-丙烯酰胺

研究了溶液聚合法制备明胶-聚(丙烯酸铵-丙烯酰胺)(G-g-PAA/PAM)可降解高吸水性树脂的方法.对明胶/单体及丙烯酸铵/丙烯酰胺质量比、丙烯酸中和度、单体浓度及N,N'-亚甲基双丙烯酰胺和过硫酸钾相对含量影响产品吸(盐)水性能的情况进行测试,从中优选出较合适的反应条件,并用红外光谱对产物进行表征.该高吸水性树脂的吸水倍率达1187g/g,吸盐水倍率选82g/g.FTIR分析表明,反应产物为明胶与丙烯铵、丙烯酰胺的接枝共聚物.     

壳聚糖接枝丙烯酸高吸水性树脂的制备及性能研究

以壳聚糖(CTS)和丙烯酸(AA)为原料进行接枝共聚,制得高吸水性树脂.通过单因素及正交试验考察AA∶CTS比值、引发剂用量及交联剂用量对树脂吸水性能的影响,确定最佳合成条件.利用红外光谱对产品结构进行表征.结果表明,当AA∶CTS为10∶1,引发剂用量为单体质量的3.5％,交联剂用量为单体质量的0.35％,所制得的树脂吸水率最高,其吸蒸馏水率可达964 g/g,吸盐水率可达58g/g.     

聚丙烯酸钠/纳米纤维素晶体-g-聚丙烯酰胺复合高吸水性树脂的制备与表征EI北大核心CSCD

先用铈(Ⅳ)盐引发丙烯酰胺(AM)在纳米纤维素晶体(NCC)表面接枝聚合,接枝产物NCC-g-PAM可稳定地分散在丙烯酸钠/丙烯酸混合单体水溶液中,然后以N,N-亚甲基双丙烯酰胺作交联剂通过原位光聚合制得聚丙烯酸钠(PAANa)/NCC-g-PAM复合高吸水性树脂。用红外光谱、X射线衍射、元素分析等方法对NCC-g-PAM进行了表征,通过红外光谱、扫描电镜、溶胀实验考察了NCC-g-PAM的添加对高吸水性树脂结构、形貌和吸水性能的影响。结果表明,NCC-g-PAM中NCC的晶态结构未改变,聚丙烯酰胺(PAM)的含量为59.54%。PAANa/NCC-g-PAM复合高吸水性树脂具有丰富的网孔结构,NCC-g-PAM中的PAM链与PAANa基体间形成了氢键。与PAANa高吸水性树脂相比,PAANa/NCC-g-PAM复合高吸水性树脂的吸水倍率和吸水速率均有所增加,吸水倍率最高可达3000 g/g,是PAANa的3.2倍,吸生理盐水倍率最高可达139 g/g,是PAANa的2.5倍。     

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 ...