常温下功能集成包装袋在甜玉米保鲜中的应用

目的常温条件下延长新鲜甜玉米的保鲜时间,为常温运输提供条件。方法使用面积比例不同的高透氧薄膜和高透水薄膜制作保鲜包装袋,用其对甜玉米进行包装贮藏,以裸放甜玉米为对照,在温度为(25±1)℃,相对湿度为(60±5)%的条件下进行保鲜实验。每天对包装袋内的氧气和二氧化碳含量变化、甜玉米质量损失率、玉米籽粒硬度、可溶固形物含量、总酸含量、Vc含量以及感官品质进行测定和分析。结果裸放组样品失重迅速,其可溶固形物含量明显降低,实验进行到第2天时甜玉米就已经失去了商品价值。在实验组中,由于2种薄膜自身的透气性能不同,使得包装袋内氧气含量迅速降低、二氧化碳迅速升高。这样的贮藏环境有效抑制了甜玉米的呼吸等生理活动,使玉米的营养物质、感官评价等指标保持在较好的水平。结论功能包装袋可以将甜玉米的货架期延长到4～5 d。     

功能集成保鲜包装设计在小油菜保鲜中的应用

目的以实验室自制功能薄膜A(高透湿性薄膜)和功能薄膜E(高透氧、高透二氧化碳薄膜)为原料,运用多功能集成设计理论,设计2种双功能集成保鲜包装袋,探索评价这种功能集成保鲜包装对小油菜保鲜的影响。方法以小油菜作为保鲜对象,评价2款双功能集成保鲜袋对包装袋内顶空气体、小油菜外观品质、维生素C含量、总可溶性固形物含量、质量损失率的影响。结果功能集成保鲜包装在常温下延长了小油菜的货架期,货架期从裸放条件下的2 d延长到4~5 d。结论双功能集成保鲜袋可以有效减缓小油菜的呼吸速率,减少营养成分的流失,维持小油菜外观品质,避免了凝露现象,有效延长了小油菜的货架期。     

孜然保鲜液对鲜切网纹瓜保鲜效果的影响

在自制可降解托盘表面涂布孜然保鲜液后覆膜包装鲜切网纹瓜,并以未涂布保鲜液托盘为对照组,对网纹瓜的感官品质、失重率、硬度、可溶性固形物含量、总酸含量和Vc含量等指标进行评价或测定。结果表明,托盘涂布孜然保鲜液组样品的感官评价得分均比对照组高;随着贮藏时间的延长,2组样品网纹瓜的失重率均不断增加,而其硬度、总酸含量、Vc含量均下降,其可溶性固形物含量均先增大后减小,但所有对照组的变化幅度均较经孜然保鲜液处理后托盘盛放样品的变化幅度大;且由实验数据可得,以涂布保鲜液托盘覆膜包装的鲜切网纹瓜的货架寿命是空白对照组的2倍。由此可得,孜然保鲜液对鲜切网纹瓜等类似果蔬具有一定的保鲜效果。     

可释放SO2保鲜包装袋在荔枝保鲜中的应用

目的为了延长荔枝在常温下的货架期。方法制备一种具有3层结构的可持续释放SO2杀菌剂的复合膜,将复合膜热封成保鲜包装袋,并以“桂味”荔枝为实验对象,以裸放组和市售食品保鲜袋处理组为对照组,研究保鲜包装袋在常温下对荔枝的保鲜效果。分析荔枝在贮藏期间的质量损失率、褐变指数、好果率、可溶性固形物含量及可滴定酸含量的变化。结果在常温下,裸放的荔枝和用市售保鲜袋包裹的荔枝在货架期第2—3天就会发生严重褐变,失去商业价值。用自制的可释放适量SO2的保鲜袋贮藏荔枝时,在货架期第6天时,质量损失率仅为2.44%,褐变指数仅为1.26,可溶性固形物和可滴定酸质量分数分别为18.6%,0.18%,好果率仍达到88.33%。结论可释放SO2的保鲜包装袋能减少荔枝水分损失,抑制褐变,保持荔枝的风味和口感,提高荔枝的商业价值,在常温下将荔枝的货架期延长至6 d左右。     

可释放SO2复合膜对葡萄保鲜性能的影响

目的延长葡萄的保鲜期。方法制备一种具有3层结构的可释放SO_2复合膜,将复合膜热封成包装袋,对保鲜包装袋释放二氧化硫的情况进行分析。以裸放葡萄为对照组,研究保鲜包装袋在23℃下对葡萄的保鲜效果。分析葡萄在贮藏期间的质量损失率、落粒率、好果率、可溶性固形物含量及硬度的变化,并观察葡萄的外观。结果保鲜包装袋可持续释放30 mg/L的SO_2 30 d以上。常温保存17 d后,裸放组的葡萄已经失去了食用价值,好果率为0%,而保鲜袋中葡萄质量损失率为1.46%、落粒率为5.1%、好果率为60%左右。结论可释放SO_2复合膜缓慢释放的SO_2可持续达到抑菌保鲜、有效延长葡萄货架期的效果。     

甜玉米微孔自发气调包装应用研究

目的确定甜玉米的微孔包装参数及其保鲜效果。方法在40μm厚的聚乙烯(PE)保鲜袋(35 cm×55 cm)上制备不同数量的微孔,孔径为(0.18±0.005)mm,孔的数量分别为2,3,6,9,20,50个。采用微孔袋对甜玉米进行包装,检测在0℃下贮藏时不同时间袋内的气体浓度,抽样分析甜玉米的营养指标、乙醇含量及感官品质。结果甜玉米贮藏前期呼吸旺盛,后期呼吸强度下降,呼吸强度的变化会引起包装袋内氧气和二氧化碳浓度的波动;低氧或高二氧化碳有利于保持甜玉米中可溶性固形物、Vc含量和可溶性糖含量,但易造成乙醇的积累和异味的产生。结论在40μm厚的PE保鲜袋上制备6个直径为(0.18±0.005)mm的微孔,对甜玉米的保鲜效果最佳,贮藏14 d,能保持良好的品质。     

不同包装材料对茄子保鲜的影响

目的以新鲜的茄子为研究对象,研究在不同的包装袋下对茄子保鲜程度的影响。方法将茄子平均分为三组:一组常温裸露为对照,二组用微孔薄膜包装袋包装,三组用PE膜包装。每隔一段时间测定茄子的失重率、硬度、维生素C含量、可滴定酸等性能。结果使用了包装袋包装的茄子保鲜效果明显优于常温裸露的对照组,两种包装袋的保鲜效果在不同时间段也各有优异。结论从实验结果来看,PE袋的茄子保鲜包装要整体优于微孔薄膜包装和空白包装。     

常温下自制功能保鲜袋对火龙果的保鲜效果研究

目的延长火龙果在常温(25±1)℃条件下的货架期。方法使用智能缓释杀菌薄膜和高透气性硅窗薄膜制备多功能集成保鲜袋(AP),并对新鲜火龙果进行保鲜实验。通过对保鲜袋的顶空气体组成、火龙果的硬度、总可溶性固形物含量、可滴定酸(TA)含量和维生素C含量的测定,研究AP多功能集成保鲜膜对火龙果的保鲜效果。结果在常温下,裸放火龙果的货架期为6 d,而AP多功能集成保鲜袋内火龙果的货架期可以延长4 d,并且可以较好地保持火龙果的品质。结论 AP膜可有效减缓硬度的降低及水分损失,同时可溶性固含量和总酸值均高于对照组。     

鱼皮蛋白酶解液复合膜对冷藏鲈鱼肉品质的影响

目的 研究鱼皮胶原蛋白酶解液复合膜处理对冷藏鲈鱼肉品质的影响.方法 将新鲜鲈鱼肉分别采用鱼皮胶原蛋白复合膜液涂覆、鱼皮胶原蛋白复合膜包裹等2种方式进行处理,以无菌水处理作为空白对照,3组样品随后置于(4±1)℃下冷藏,期间进行感官、质量损失、色泽、总挥发性盐基氮(Total Volatile Base Nitrogen,TVB-N)、菌落总数(Total Viable Count,TVC)等指标的测定,综合评价不同处理方式对冷藏鲈鱼肉品质的影响.结果 膜液涂覆、膜包裹处理组样品的感官、质量损失、色泽、TVB-N值、TVC值等指标均优于空白对照组.其中,膜包裹组可保鲜8d左右,到第8天时,该处理组样品的TVC值含量为5.98 lg(CFU/g),TVB-N值含量为251.2 mg/kg;膜液涂覆处理可保鲜12d左右,12 d之后开始逐渐变质,说明膜液涂覆可用于鱼肉的保鲜,以延长其冷藏货架期.结论 与空白对照组样品相比,膜液涂覆和膜包裹处理均能在一定程度上保持鲈鱼肉的新鲜程度,其中膜包裹处理对鲈鱼肉的保鲜效果最佳.     

温度波动对猕猴桃在4 ℃下货架贮藏品质的影响

目的 明确不同温度波动幅度对猕猴桃微环境参数和贮藏品质的影响.方法 以"徐香"猕猴桃为实验材料,采用聚乙烯膜(Polyethylene,PE)包装扎口后装于白色塑料筐中,分别放置于(4±1),(4±2),(4±3),(4±4)℃的保鲜箱内贮藏,监测PE膜包装袋中微环境气体CO2,O2,C2H4含量的变化,每6 d测定相关品质指标.结果 贮藏结束时,(4±1)℃实验组猕猴桃的质量损失率、硬度、可溶性固形物含量、维生素C含量、细胞膜透率分别为0.66％,0.58 kg/cm2,14.2％(质量分数),683.5 mg/kg和50.32％,小幅度的温度波动有效抑制了猕猴桃的软化和营养物质的流失,延缓了呼吸高峰的出现和乙烯的释放.结论 温度波动幅度越小越有利于延缓猕猴桃的衰老速度,维持贮藏品质.     

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...     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

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.     

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.……     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.