PCV电线波纹管配方的正交设计

通过正交设计，初步得出了PVC线波纹管混合润滑剂的组成及比例，确定了PVC电线波纹管的配方。     

户外耐候环保PVC电线波纹管的研制

本文从无铅化、增韧、增强、抗粉化四个方面对PVC配方进行了研究,制备了户外用耐候环保阻燃PVC电线波纹管。研究结果表明:稀土稳定剂的热稳定作用优于钙锌稳定剂而与铅盐稳定剂接近。纳米碳酸钙的加入可以用较少的ACR使制备的PVC复合材料达到超韧,同时亦提高了PVC复合材料的弯曲模量,表现出增韧和增强的双重作用。使用稀土热稳定的体系的抗粉化能力优于钙锌热稳定体系;加了钛白粉和炭黑的试样都能明显提高抗粉化能力,其中的炭黑的抗粉化能力更好一些。所制备的PVC电线波纹管的重金属含量符合ROHS要求、有害物质含量符合REACH要求;能通过-40℃扁平实验、80℃扁平实验和通过1000小时加速老化实验、产品阻燃等级为UL94-1999V0,可满足长期户外使用要求。     

牵引式PVC波纹管打孔装置

介绍了一种牵引式PVC波纹管打孔装置,其采用拨齿轮来推动PVC波纹管前进,不仅推进过程平稳,而且提高了打孔的准确性。     

新型PVC-M环保高抗冲双壁波纹管的开发与应用

介绍了新型PVC-M环保高抗冲双壁波纹管的刚韧平衡,解决了传统PVC管材强而不韧、韧而不强的缺点,弥补了PVC管材韧性差,PE管材强度低的不足,同时解决了PVC波纹管的低温脆性。     

PVC波纹管在预应力混凝土工程中的试验应用

制备了PVC波纹管,按照JT/T 529—2016测试了其主要性能,并与HDPE波纹管进行了比较;对PV C波纹管进行了热失重试验、浸泡试验和环境模拟加速试验。结果表明:(1)PV C波纹管的基本性能满足JT/T529—2016的要求,且优于相同规格、壁厚的H D PE波纹管;(2)PV C波纹管在210℃以下时热失重0.5%,性能稳定可靠;(3)PVC波纹管在40℃去离子水中浸泡90天的过程中无Cl-析出;(4)5 000 h环境模拟加速试验过程中,PV C波纹管内外侧20 m m范围内无C l-析出。     

江西宏远化工有限公司

正本公司是专业生产PVC塑料助剂企业,其"恒佳信"牌产品有:(一)改性水滑石;(二)钙锌复合稳定剂系列;电线电缆、给水管、管件、型材;(三)硬脂酸盐系列;硬脂酸铅、钡、镁、钙、锌及辅助产品三、二盐等;(四)无尘复合稳定剂系列;管材、管件、板材、型材、波纹管和电线、电缆;     

可内穿铁丝的环保型PE／PVC单壁波纹管生产线

日前，一种可生产直径6～110mm环保型PE／PVC单壁波纹管的塑机设备在青岛科丰源塑料机械有限公司研制成功。行业专家称，该生产线中的内穿铁丝技术属国内首创，其生产出的环保型PE／PVC单壁波纹管用途广泛，必将赢得新一轮市场商机。     

塑料波纹管成型技术

<正> 塑料波纹管具有质轻价廉,刚柔相济,使用方便等特点,广泛应用于建筑物预埋管,电线保护管,各行业的通风及输液管等。美国1977年塑料波纹管用量是13.97万吨,到1991年用量已突破24.7万吨,意大利自研制出塑料波纹管生产设备以来,建筑电气配线几乎全部采用了波纹管。随着应用领域的扩展,塑料波纹管的种类也在增多,目前日本塑料波纹管已达260多种。     

耐热70℃—PVC电缆粒料在南宁化工厂试制成功

南宁化工厂充分利用自产聚氯乙烯(PVC树脂)树脂的原料优势,大力发展聚氯乙烯树脂的深度加工产品,试制成功耐热70℃—PVC电缆粒料。并建成了规模为1500吨/年电缆粒料的生产装置,试产情况良好。耐热70℃—PVC电缆粒料是目前国内外生产电缆、电线的重要原料,我区每年需要近2500吨,都要从区外购进。南化开发这一产品,可满足我区电缆、电线生产厂家的需要,从此结束南宁、桂林电缆、电线     

江西宏远化工有限公司

正本公司是专业生产PVC塑料助剂企业,其"恒佳信"牌产品有:(一)改性水滑石;(二)钙锌复合稳定剂系列;电线电缆、给水管、管件、型材;(三)硬脂酸盐系列;硬脂酸铅、钡、镁、钙、锌及辅助产品三、二盐等;(四)无尘复合稳定剂系列;管材、管件、板材、型材、波纹管和电线、电缆;(五)润滑剂系列;聚乙烯蜡、氧化聚乙烯蜡、单甘酯、乙撑双硬脂酰胺等、塑料光亮润滑剂;(六)稀土铝酸酯偶联剂;(七)PVC增强增韧剂;(八)氧化聚丙烯硅烷(CPS-680)     

Failure of tannic acid to inhibit digestion or reduce digestibility of plant protein in gut fluids of insect herbivores

The rate of hydrolysis of the abundant foliar protein, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPC), in enzymatically active gut fluid ofManduca sexta larvae is very rapid and is unaffected by the presence of tannic acid, even when tannic acid is present in the incubation mixture in amounts in excess of the amount of RuBPC. When this protein is dissolved in the denatured gut fluids ofM. sexta larvae orSchistocerca gregaria nymphs, large amounts of tannic acid must be added to bring about the precipitation of significant quantities of protein. The ability of insect gut fluid to prevent the formation of insoluble tannin-protein complexes is due to the presence of surfactants. On the basis of our results and a review of the findings of other investigators, we argue that there is no evidence that tannins reduce the nutritional value of an insect's food by inhibiting digestive enzymes or by reducing the digestibility of ingested proteins and, further, that the failure of tannins to interfere with digestion is readily explained on the basis of well-documented characteristics of the digestive systems of herbivorous insects. In challenging the currently popular notion that tannins are digestibility-reducing substances, we do not challenge the general utility of either the apparency theory or resource availability theory of plant defense. In debating the merits of these two analyses of plant-herbivore interactions, however, the demise of tannins as all-purpose, dose-dependent, digestibility-reducing defensive substances must be taken into account.     

机制砂岩性与级配对混凝土抗硫酸盐侵蚀性能的影响

为了探究不同岩性、不同级配机制砂对混凝土性能的影响,对三种不同岩性机制砂混凝土及天然河砂混凝土的工作性和抗压强度进行研究。此外,对比分析了四种混凝土在干湿循环制度下的抗硫酸盐侵蚀性能。结果表明,天然河砂混凝土的工作性优于机制砂混凝土,钙质机制砂混凝土的工作性略好于硅质机制砂混凝土。机制砂混凝土的抗压强度优于天然河砂混凝土,在硫酸盐侵蚀循环作用下的力学性能变化趋势与天然河砂混凝土基本一致。在相同级配条件下,机制砂混凝土的抗蚀系数高于天然河砂混凝土;机制砂岩性并不会对混凝土抗硫酸盐侵蚀性能带来负面影响。级配良好的机制砂可以增强混凝土抗压强度和抗硫酸盐侵蚀性能。     

Functional properties of proteins in foods

The measurement of functionality of protein food ingredients has developed somewhat haphazardly, probably due to the wide range of proteins used as ingredients and the diversity of foods. Studies of the physiochemical properties of proteins should enable prediction of a proteins response to process environments and prove more fruitful than many of the empirical measurements of functionality. The effects of pH, salt type and concentration on the phase behaviour of the oilseed globulin and arachin, demonstrates the complexity of protein solubility and the inadequacies of simple tests that have arisen. Studies of the effects of salts and conditioning on meat fibres, coupled with measurement of the location of water in pellets from water holding tests enable the latter to be applied with increased confidence. Comparison of the endothermic transitions observed on heating with the development of storage and loss moduli allow the contributions of domains of skeletal muscle myosin to gel structure to be investigated.     

Aggregation pheromone system of adult gregarious desert locust schistocerca gregaria (forskal)

Six electrophysiologically active aromatic compounds, viz., anisole, benzaldehyde, veratrole, guaiacol, phenylacetonitrile, and phenol, were identified in the volatiles of older-adult male desert locust. Young adults and females of all age groups produced none or only trace quantities of these compounds. Comparison of the aggregation responses of young and older adults to the crude, older-adult, volatile extract and different synthetic blends of the six compounds showed that the aggregation pheromone system of the adult gregarious locust consists of phenylacetonitrile, guaiacol, phenol, and benzaldehyde. Like the crude volatile extract of older males, neither the synthetic blend of the six compounds nor the adult pheromone blend evoked any significant aggregation responses from nymphs. These results confirm our previous report of sexual differentiation in the production of adult aggregation pheromone in the desert locust and of the evidence of two distinct aggregation pheromone systems in the two stages of the insect.     

Molecular mechanics modelling of interfacial energy and flexibility on cellulose

Molecular mechanics modelling is used to calculate the energies of interaction, hence the molecular level energy of adhesion at the interface with crystalline cellulose I of three different photopolymerizable primers and of a polyester varnish at the interface with the primer/cellulose assembly. The energy of interactions for just one of the primers with the statistically most common conformation of amorphous cellulose has also been obtained for comparison. Experimental results of adhesion by a standard peel test and by thermomechanical analysis, in which the effect of viscoelastic energy dissipation by crack tip propagation has been respectively minimized or is not present, hence in which the energy of interfacial interaction is nothing else but the work of adhesion, correlated well with the energies of interaction calculated by molecular mechanics. An equation correlating the energy of interaction at each finish/cellulose interface with the deflection derived by thermomechanical analysis, and with the number of internal bond rotational degrees of freedom as well as the degree of networking of the finish, has been derived and is presented. A relationship between the intrinsic fracture energy Go and the molecular mechanics-derived energy of interaction at the interface equating this to the square of the work of adhesion is obtained and is presented.     

Distribution of birch (Betula SPP.), willow (Salix SPP.), and poplar (Populus SPP.) secondary metabolites and their potential role as chemical defense against herbivores

Isoprenoids and phenolics, major metabolites of important browse species, are reviewed in regard to concentrations, distribution within tissues, and between species. Seasonal variation of specific substances and changes with age of the plant are also considered. The distribution of substances may affect food selection and feeding behavior of animals. Wild mammalian herbivores tend to avoid plant parts rich in these substances, in spite of high nutritional content of the plant tissue. Possible mechanisms for defense by plants against depredation by mammalian herbivores are discussed within the framework of the plants' biochemistry.     

Sr改性Cu催化剂的果糖加氢制备甘露醇性能

使用共沉淀法制备负载Cu催化剂。通过添加碱土金属Sr，对Cu催化剂进行了改性，以提高Cu催化剂在果糖加氢制备甘露醇过程中的活性和选择性。采用ICP-MS、TEM、XRD、H₂-TPR、XPS和CO₂-TPD等对所制备的催化剂进行了系统表征。结果表明：Sr的添加能增大催化剂的比表面积，促进活性组分Cu的分散，从而提高了催化剂的活性，并且增加了催化剂的碱性，使果糖优先形成β-呋喃糖中间体，从而提高了甘露醇的选择性。在果糖浓度为1.1 mol·L^-1、催化剂用量为反应物质量的6%、反应温度为373 K、反应氢压为4.0 MPa、Cu/Sr原子比为7∶1的反应条件下，果糖转化率为99%，甘露醇的选择性为79%。催化剂循环使用了20次，其催化稳定性基本保持不变。     

接触式机械密封界面泄漏机理研究的关键科学问题

密封界面的泄漏机理是机械密封研究与应用的焦点问题之一,涉及泄漏通道表征、粗糙表面的接触力学模型、界面微观形貌变化以及介质流体在泄漏通道中的流动阻力等问题。回顾了近几十年国内外接触式机械密封泄漏通道模型的研究,深入分析了G-W模型、M-B模型和Persson模型3种粗糙表面接触力学模型的贡献和存在的问题,提出了一种基于逾渗理论的泄漏通道新模型;探讨了密封界面的分形参数、泄漏通道的流动阻力以及密封界面的有限尺寸效应对泄漏特性的影响,指出孔隙连通贯穿界面和流体流经贯穿通道的流动阻力小是密封界面产生泄漏的成因,以及泄漏通道的形成和泄漏通道内的流体流动特性是泄漏机理研究的主要方向。     

Measured kinetics of the acid-catalysed hydrolysis of sugar cane bagasse to produce xylose

Experimental trials of the water hydrolysis of bagasse to produce xylose, arabinose and glucose were conducted using a temperature-controlled microwave digester. The experimental variables were temperature, ratio of water mass to bagasse mass, type of bagasse material and reaction time. The pH of the liquid and concentration of dissolved xylose, arabinose and glucose were measured at the completion of each trial. Kinetic modelling of the global rates of formation of monosaccharide products was performed using schemes based on earlier researchers’ models of acid hydrolysis using mineral acids. For the most plentiful product, xylose, the most accurate kinetic model of the global reactions was determined to be two parallel pathways for hydrolysis of xylan to xylose followed by a single pathway for xylose decomposition. The calculated activation energies of the reactions were within the range reported by other researchers for the hydrolysis of a range of lignocellulosic materials using mineral acids.