表面接枝改性对PET薄膜包装特性的影响

以PET薄膜为研究对象,首先运用过硫酸铵水相热分解使其表面羟基化,再在氧化-还原引发剂的存在下,引发丙烯酸单体自由基接枝聚合,在薄膜表面形成对环境湿度敏感的可溶胀的聚丙烯酸水凝胶层.研究结果表明:该表面接枝聚丙烯酸对材料的阻湿性没有显著影响;而干态下由于羧基间的氢键作用,薄膜氧气透过率,羧基接枝浓度的增加而减小;同时,改性后表面粗糙度增加,薄膜的静摩擦系数和动摩擦系数都随着羟基化处理时间的延长、表面[COOH]的增加而增加.     

低温等离子体液相接枝处理电纺PET膜的制备与研究

采用氮气(N2)低温等离子体引发苯二甲酸乙二醇酯(PET)纳米纤维薄膜表面接枝,液相低温等离子体处理接枝丙烯酸单体,通过电镜照片、水接触角测试、FTIR测试及力学测试,讨论了液相接枝处理后,薄膜的形态及性能的变化。实验中接枝处理的工艺条件是,丙烯酸接枝溶液体积浓度10%,接枝温度60℃,接枝时间2h。液相低温等离子体接枝处理后,薄膜的表面亲水性得到了有效的提高。     

脉冲微波表面波PECVD在有机PET表面沉积DLC薄膜的阻隔性研究

目的 探讨使用脉冲微波表面波等离子体辅助化学气相沉积技术在聚对苯二甲酸乙二醇酯（PET）材料表面沉积类金刚石薄膜作为阻隔层的可行性。方法 以C2H2为单体,氩（Ar）为放电气体,采用脉冲微波表面波等离子体化学气相沉积（PECVD）技术在有机PET材料表面沉积类金刚石（Diamond-like Carbon, DLC）薄膜。研究工艺参数,如脉冲微波放电功率、工作气压、单体与工作气体的体积比等,对DLC薄膜沉积速率和阻隔性能的影响。通过傅里叶变换红外光谱（FT-IR）、原子力显微镜（AFM）、氧气和水蒸气透过率测试仪等对薄膜结构与性能进行表征。结果 DLC薄膜的结构和成分随着等离子体放电工艺参数的变化而改变,造成其阻隔性能也随之发生变化。PET表面沉积纳米级DLC薄膜后,氧气透过率和水蒸气透过率可以分别降至0.58 mL/(m2?d)和2.5 g/(m2?d)。结论 DLC薄膜对氧气和水蒸气都表现出良好的阻隔性,可以应用于食品、药品的阻隔包装。     

射频等离子体改性工艺与氧化铟锡薄膜性能研究

采用正交实验方法研究了氧气等离子体表面改性中各工艺因素对ITO薄膜表面性质的影响,获得了IID表面改性的最佳工艺条件,并且通过XPS,AFM,透射光谱的分析以及薄膜表面接触角和方块电阻的测量,表征了优化工艺条件下氧气等离子体处理前后ITO薄膜的表面性质.结果表明,氧气等离子体处理降低了ITO表面的粗糙度和方块电阻,改善了ITO表面的化学组分和浸润性能.另外,以表面处理前后的ITO基片作为空穴注入电极,采用真空热蒸镀技术制备了有机薄膜电致发光(OTFEL)器件,并对器件的电流.电压.亮度特性以及电流效率进行了测试和分析,实验结果显示,氧气等离子体处理降低了启亮电压和驱动电压,提高了发光亮度和电流效率,有效地改善了OTFEL器件的光电性能.     

钛种植体表面润湿性控制的实验研究

首先用喷砂酸蚀法对钛种植体表面进行粗化处理,制备出具有微米-纳米双微观孔洞结构的超亲水表面.然后用等离子体氧化的工艺,制备具有超亲水性能的氧化钛表面,发现表面亲水性能随自偏压的增加先减小后增加,随处理时间的增加而减小.在360 V自偏压、20 min处理时间和1ml/min(标准状态)氧气流量时能到超亲水效果的锐钛矿二氧化钛表面.最后尝试用十二烷基三氯硅烷和分子自组装法在粗糙的氧化钛表面制备疏水表面,最大角度可达120°,利用等离子体处理和紫外光照射成功实现了表面由超亲水到疏水之间的转换.     

表面接枝改性对聚乙烯薄膜阻隔性的影响

以PE包装膜为研究对象,首先通过过硫酸铵水相热分解使其表面羟基化,再在氧化-还原引发剂的存在下,引发丙烯酸单体自由基接枝聚合,在薄膜表面形成可溶胀的聚丙烯酸水凝胶层.研究结果表明,该表面接枝聚合反应对材料的阻水性没有显著影响;相反,由于干态下游离羧基间强烈的氢键作用,增加了O2分子透过的薄膜的阻力,薄膜氧气透过率随游离羧基浓度的增加而显著减小.     

HDPE薄膜低温等离子体改性与粘接性能研究

利用氧气低温等离子体,在真空度为20 Pa,处理功率为30 W的条件下,对高密度聚乙烯(HDPE)薄膜进行了表面改性。研究结果表明:在20~200 s的处理时间内,单位面积的失重率随处理时间的增加线性增大,表面粗糙度也随着增加;处理后薄膜表面的接触角显著减小;接触角越小,剥离强度就越大;处理后能在薄膜表面形成羟基、羰基和羧基等各种极性基团。     

等离子体喷涂氧化钛涂层的生物活性研究

以纳米TiO₂粉末为喷涂原料, 采用大气等离子体喷涂技术在医用钛合金上制备氧化钛涂层. 利用酸和碱溶液对氧化钛涂层表面进行生物活化处理, 体外模拟体液浸泡实验考察涂层的生物活性. 采用XRD、SEM、FTIR、EDS等测试技术对改性前后氧化钛涂层的生物活性进行表征. 结果表明: 氧化钛涂层和钛合金基体的结合强度较高, 其值高达40MPa, 涂层的耐模拟体液腐蚀性优于钛合金. 酸和碱溶液表面改性后的氧化钛涂层经模拟体液浸泡可在其表面生成含有碳酸根的羟基磷灰石(类骨磷灰石), 显示良好的生物活性.     

M-PECVD制备高阻隔薄膜研究

在传统的等离子体增强化学气相沉积(plasma-enhanced chemical vapor deposition)技术基础上,通过添加磁场来约束等离子体相中的电子,增加单体有机大分子的电离率,称为磁化等离子体(M-PECVD)技术。实验采用六甲基二硅氧烷和氧气混合气体作为沉积氧化硅薄膜的前驱气体,在厚度为12μm的PET薄膜表面沉积氧化硅薄膜。通过FTIR分析薄膜的结构成分,表明不同的功率对沉积薄膜的结构没有影响,只是对应于1030cm-1的Si—O峰的强度不一样.氧气透过率(OTR)测量发现:随着功率升高,薄膜的OTR先降低,在功率为190W时为最小值(OTR=0.732mL/m2/day);然后随着功率的增大,扫描电镜(Scanning electronic microscopy)OTR上升至2.0mL/m2/day,并保持不变。为了进一步研究薄膜的表面形貌和阻隔性能的关系,通过SEM进行表面相貌分析,发现沉积薄膜表面为有序的棒状结构,并通过薄膜的截面图推算出薄膜沉积速率为4.0nm/s。     

DBD-PECVD法制备CN薄膜的结构及性能研究

使用自行设计的真空系统,采用介质阻挡放电等离子体增强化学气相沉积(DBD-PECVD)法,分别以CH4/N2、C2H2/N2、C2H4/N2混合气体作为反应气体,在单晶硅片上成功制备了CN薄膜.FTIR结果证实了薄膜中碳氮原子结合成化学键,Raman结果说明薄膜中含有类金刚石结构,AFM结果表明薄膜粗糙度随放电气压的升高而逐渐增大.三种混合气体沉积的CN薄膜,以CH4/N2的沉积速度最慢,薄膜表面粗糙度最小,含H量最少;C2H2/N2的沉积速度最快,薄膜表面粗糙度最大.     

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 ...