气调包装对软枣猕猴桃品质的影响

目的 研究自发气调处理对采后软枣猕猴桃果实品质的影响。方法 将软枣猕猴桃置于塑料气调箱内,气调处理组果实放入气调箱封盖处理,对照组进行不封盖处理,于4 ℃下贮藏64 d,每16 d对软枣猕猴桃呼吸代谢及抗性相关指标进行测定,即气调箱内CO2和O2含量,可溶性固形物（TSS）、丙二醛（MDA）、总酚含量,及抗氧化相关酶活性等指标。结果 自发气调处理能够使CO2和O2含量维持在适宜的贮藏范围内,从而保持较高的TSS和总酚含量,抑制MDA含量及多酚氧化酶（PPO）活性,增强过氧化物酶（POD）、苯丙氨酸解氨酶（PAL）和过氧化氢酶（CAT）活性。结论 贮藏48~64 d,自发气调处理软枣猕猴桃的最适宜气体环境为体积分数3%左右的CO2和体积分数16%左右的O2,保持了软枣猕猴桃较好品质的机制,通过诱导果实的苯丙烷及抗氧化代谢实现。     

乙醇熏蒸处理对采后蓝莓果实品质的影响

目的研究乙醇熏蒸处理对采后蓝莓果实品质的影响。方法采用体积分数0.1%的乙醇于10℃下熏蒸蓝莓果实24 h,随后贮藏于(5±1)℃下,以5 d为1个周期观察乙醇熏蒸处理对蓝莓贮藏品质变化的影响,并对果实的风味、腐烂率、质量损失率、硬度、颜色饱和度、呼吸强度、可溶性固形物(TSS)、总酚、花青素、多酚氧化酶(PPO)、过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)、羟自由基清除率和总抗氧化能力进行分析对比。结果与对照组相比,乙醇熏蒸处理可有效抑制蓝莓的软化和腐烂,减缓果实中TSS的下降及水分的丧失,提高蓝莓果实中的花青素含量、总酚含量、抗氧化相关酶活性、羟自由基清除率量及总抗氧化能力。结论体积分数0.1%的乙醇熏蒸处理采后蓝莓可有效抑制蓝莓的腐烂与软化,维持果实原有风味,保持蓝莓品质,延长蓝莓的货架期。     

植物激素影响蓝莓果实采后衰老进程研究进展

目的概述不同植物激素及生长调节剂作用机理,探讨其在采后蓝莓果实衰老过程中的作用,展望如何延长蓝莓果实的贮藏期。方法介绍植物激素乙烯、水杨酸(SA)、茉莉酸甲酯(MeJA)、脱落酸(ABA)及植物生长调节剂1-甲基环丙烯(1-MCP)的作用,及其对采后蓝莓果实衰老进程的影响和在保鲜领域的应用。结果由于蓝莓果实成熟于高温多雨的季节,且其果实含水率高、果皮薄,导致其贮藏性差,采后极易发生软化,最终衰老腐烂。近年来的研究表明除细胞壁降解酶类之外,内源激素含量也能调控果实的成熟及衰老,而施用不同植物激素及生长调节剂则是延缓果实衰老的有效措施。结论高浓度外源乙烯及脱落酸的施用会加速果实软化及衰老现象的发生,适当浓度的乙烯、1-MCP、SA、MeJA处理可以延缓果蔬采后衰老所带来的腐败变质进程。     

1-MCP处理对早晚熟枇杷鲜果采后生理效应的影响

目的研究气调保鲜包装结合1-甲基环丙烯(1-Methylcyclopropene,1-MCP)处理对枇杷采后生理效应的影响。方法以早晚熟"白玉"、"丰玉"枇杷为实验材料,采用1-甲基环丙烯对其进行处理,再使用气调保鲜包装(厚度35μm),将其在冷藏温度为(6±1)℃的条件下贮藏,观察其采后生理变化特性及不同品种之间的贮藏性能差异。结果 1-MCP处理可抑制枇杷果实硬度、可溶性固形物含量和可滴定酸含量的下降,延缓枇杷的褐变、过氧化物酶(Peroxidase,POD)活性的上升,减少枇杷的腐烂率,促进枇杷果实多酚氧化酶活性(Polyphenoloxidase,PPO)、脂氧合酶(Lipoxygenase,LOX)活性的下降。枇杷品种白玉的呼吸速率、POD、PPO活性及褐变指数较丰玉高,LOX活性和丙二醛(Malondialdehyde,MDA)含量增加明显,其硬度和营养成分含量较低;丰玉的腐烂率高于白玉。结论采用气调保鲜包装结合1-MCP处理延缓了枇杷在冷藏过程中营养物质的下降,进而延迟了枇杷褐变和衰老进程。其中早熟品种白玉枇杷的褐变发生率和膜脂过氧化程度更高。     

采前喷施复合保鲜液对蓝莓贮藏品质的影响

目的 研究采前喷施丁香提取液结合壳聚糖对蓝莓贮藏品质的影响.方法 以蓝莓为材料,采用3种处理方法(丁香提取液、壳聚糖、丁香提取液结合壳聚糖)对采后蓝莓进行低温((1±0.5)℃)贮藏,并设置对照组,研究不同处理方式对蓝莓贮藏品质变化的影响.结果 与对照组比较,处理组均能够延缓蓝莓的生理代谢,其中采前喷施丁香提取液结合壳聚糖的复合保鲜液对蓝莓的保鲜效果优于单独处理,能够更好地降低采后蓝莓的腐烂率、呼吸强度和乙烯生成速率,抑制果实的硬度、可溶性固形物含量、花色苷含量的下降,保持蓝莓的多聚半乳糖醛酸酶、过氧化氢酶和脂氧合酶活性,并且显著降低采后蓝莓果实表面的霉菌和酵母菌的菌落总数(P<0.05).结论 采前喷施丁香提取液结合壳聚糖对采后蓝莓果实的贮藏效果最好,能够明显降低蓝莓果实的生理代谢,保持更好的贮藏品质.     

动态气调贮藏对蓝莓采后生理代谢品质的影响

目的以"奥尼尔"蓝莓为实验材料,研究在1℃下,普通贮藏、静态气调包装(O_2和CO_2的体积分数分别为5%,30%)和动态气调包装(在O_2和CO_2的体积分数分别为5%,50%的环境中贮藏4 d后转为O_2和CO_2的体积分数分别为5%,30%)对采后蓝莓果实生理品质以及耐藏性的影响。方法以7 d为周期,对酶促防御系统的酶活性、抗性相关酶活性、非酶促防御系统的抗氧化物质的含量、呼吸速率、果实硬度进行测定。结果与普通贮藏相比,动态气调贮藏以及静态贮藏均激发了果实自身的防御系统,而动态气调包装更能够使过氧化物酶、过氧化氢酶和超氧化物歧化酶的活性得到提高,有效控制了还原性谷胱甘肽的下降,减缓了维生素C含量的降低速率,减缓了丙二醛生成的速率,同时也抑制了多酚氧化酶的活性,有效抑制了蓝莓的褐变与腐败变质。结论动态气调贮藏能够有效控制蓝莓的衰老与腐败,维持果实原有风味,延长蓝莓的贮藏期与货架期。     

基于聚乳酸的草莓自发气调包装薄膜设计

目的研究材料气体透过性及选择透过性对草莓自发气调包装效果的影响。方法以密闭系统法测定草莓的呼吸速率,结合米氏方程推导呼吸速率与包装膜渗透性的关系式。采用已知渗透性的薄膜结合渗透系统法测定实际贮藏中达到动态平衡时草莓的呼吸速率,根据米氏和动态平衡方程推导适宜草莓自发气调材料的气体选择比。在此基础上,选用对CO_2具有较强选择溶解性的聚乙二醇(PEG)对聚(L-乳酸)(PLLA)进行改性,调整其透气性和CO_2/O_2选择透过性。结果在一定使用面积下,经PEG改性后的PLGL35G20膜包装内的气氛组成可以达到较理想的草莓的AMAP气调浓度。结论PEG起到了良好的调节PLLA薄膜气调包装性能的效果,推测通过调节PEG嵌段和PLLA嵌段的长度及PEG在共聚物薄膜中的含量,可调控薄膜的气体渗透性和选择性,最终使其满足不同果实自发气调包装的最佳要求。     

1-MCP复合GA3处理对乌龙头贮藏品质的影响

目的 为探究不同保鲜剂对乌龙头贮藏品质的影响,筛选出适宜的保鲜剂,为乌龙头贮藏保鲜提供参考依据。方法 以“长白”乌龙头为研究对象,分别采用含量为3 μL/L的1-甲基环丙烯(1-MCP)熏蒸12 h、质量浓度为200 mg/L的赤霉素(GA3)溶液浸泡3 min和含量为3 μL/L的1-MCP熏蒸12 h后于质量浓度为200 mg/L的GA3溶液中浸泡3 min,浸泡后晾干,于0 ℃下贮藏,每隔4 d测定乌龙头的感官品质、腐烂指数、呼吸速率、质量损失率、叶绿素含量、色度值、粗纤维含量、丙二醛(MDA)含量、过氧化物酶(POD)活性和多酚氧化酶(PPO)活性等指标。结果 对照处理于0 ℃下贮藏期仅为12 d,贮藏后期出现感官品质下降、叶绿素流失、PPO和POD活性增高、异味严重的现象,失去商品性。贮藏期间,各保鲜剂处理能显著延缓采后“长白”乌龙头感官品质的下降,抑制呼吸速率、腐烂指数和粗纤维含量的升高,有效保持叶绿素含量和色度a^*值,抑制MDA含量的积累,同时能够抑制贮藏期间乌龙头的POD和PPO活性的上升,提升其抗氧化能力。其中,以1-MCP复合GA3处理后的保鲜效果最佳,保鲜效果优于单一保鲜剂处理。贮藏20 d时,1-MCP复合GA3处理组乌龙头的感官品质为80.2、腐烂指数为0.02、质量损失率为6.44%、叶绿素含量为3.7 mg/g、色度a^*值为−5.1、MDA的含量为4.7 μmol/g、POD活性为37.2 U/g、PPO活性为16.6 U/g。结论 1-MCP复合GA3处理后的保鲜效果最佳,能够抑制乌龙头腐烂,保持其营养品质,贮藏期延长了8 d。     

乙醇熏蒸结合乙烯吸附剂对蓝莓保鲜效果的影响

目的 研究乙醇熏蒸结合乙烯吸附剂对蓝莓保鲜效果的影响。方法 以“粉蓝”蓝莓为实验材料,采用对照（CK）及3种处理方法（乙醇;乙烯吸附剂;乙醇+乙烯吸附剂）对蓝莓在贮藏温度(1±0.5)℃下进行保鲜,研究不同处理方法对蓝莓贮藏期间品质的变化。结果 3种处理方法能够降低蓝莓的生理代谢水平,有利于保持蓝莓果实的贮藏品质。其中乙醇结合乙烯吸附剂更有利于降低蓝莓的果实腐烂率、呼吸强度和乙烯生成速率,能有效地抑制蓝莓贮藏期果实硬度的下降,能有效地延缓可溶性固形物、可滴定酸和花色苷含量的降低,能较好地保持蓝莓果实超氧化物歧化酶（SOD）、多聚半乳糖醛酸酶（PG）、过氧化氢酶（CAT）和过氧化物酶（POD）的活性。结论 采用乙醇结合乙烯吸附剂的处理方法对蓝莓果实保鲜的效果最好,能够更好地维持蓝莓的贮藏品质。     

不同温度下1-MCP处理对枸杞鲜果贮藏品质的影响

目的 明确不同温度下1-MCP处理对微环境气调包装枸杞冷藏品质和香气成分的影响.方法 以枸杞鲜果为实验对象,分别在0℃和20℃下进行1-MCP处理24 h,然后在-(0.5±0.3)℃环境中进行微环境气调保鲜贮藏,探究不同处理方式(mMAP、常温1-MCP+mMAP、低温1-MCP+mMAP)对贮藏期内枸杞鲜果腐烂率、果皮硬度、呼吸速率、乙烯生成速率、相对电导率、可溶性固形物、可滴定酸、维生素C、色差和整体香气成分的影响.结果 低温1-MCP处理结合微环境气调保鲜技术能够减少枸杞果实在贮藏过程中的生命活动,与常温处理相比,低温处理能够使果实在贮藏50 d时的腐烂率降低至16.42％,同时降低了呼吸速率降和乙烯生成速率,维持了果实的果皮硬度,延缓了果实相对电导率、维生素C含量的上升和L*,a*,b*的下降.并发现贮藏期间2个处理组果实的香气成分差异逐渐减小,在贮藏30 d后无明显差异.结论 低温1-MCP处理能够保护微环境气调冷藏枸杞的口感、色泽,避免了果实的腐烂衰老,使果实在经过50 d的贮藏期后仍能保持较好的商业价值.     

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.     

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.……     

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.     

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.