相变蓄冷剂对冷链包装温控效果的影响

目的 研究不同相变蓄冷剂对冷链运输包装传热性能和温控时间的影响。方法 通过采用独特的包装结构设计,并根据运输环境温度对蓄冷剂进行不同的预处理,充分利用相变材料在固-液相态转变过程中良好的温控性能。结果 在保温箱体性能参数不变的情况下,其温控时间取决于所用相变材料的相变温度和相变焓值。在极端高温、极端低温和交变温度条件下,采用熔点为5 ℃的相变蓄冷剂,可以将包装的保温时间从1 h延长至80 h以上,而且包装内保持了长时间4~5 ℃的恒温平台;采用熔点为0 ℃的水作为蓄冷剂,包装内则会出现长时间的过冷,温度平台在?1~2 ℃范围内。实验测得的包装保温时间与传热计算所得的理论值相吻合,偏差不大于±10%。结论 采用合适的相变蓄冷剂可以大大延长温控包装的保温时间,并通过对蓄冷剂进行有效的预处理,在各种极端温度环境下均可确保冷藏药品的运输安全。     

新型有机-无机复合相变蓄冷材料的制备及性能研究

以六水氯化钙为基材，配备出一种新型复合相变蓄冷材料用于空调蓄冷。该材料的质量配比为81%六水氯化钙+5%乙醇+14%丙三醇。为了降低复合相变材料的过冷度，使用六水氯化铯为成核剂，发现成核剂的添加量为1.0%时过冷度几乎为零。为检验复合相变材料的热稳定性，进行了100次的热循环实验，材料未出现相分层，表明其热稳定性能良好。     

冷冻产品用无机盐相变蓄冷材料的制备及性能研究

研制了一种适用于冷冻产品贮藏运输的高效低温无机盐相变蓄冷材料。将NH4Br、KCl、CaCl_2等无机盐与NH_4Cl复配,利用差式扫描量热仪(DSC)筛选了NH_4Br-NH_4Cl无机盐共混物作为主储能剂,通过添加不同成核剂改善过冷性能,添加不同浓度的黄源胶改善相分离。结果表明:以30%(wt,质量分数,下同)NH_4Br-NH_4Cl无机盐共混物作为主储能剂,1%SrCl_2作为成核剂,5%黄原胶作为增稠剂可获得相变温度为-18~-22℃、相变潜热为288.7J/g、过冷度小、无相分离的相变蓄冷材料。NH_4Br-NH_4Cl无机盐共混物作为主储能剂能够达到冷冻产品温度且对相变潜热影响较小,SrCl_2作为成核剂基本无过冷,黄原胶作为增稠剂解决相分离具有显著效果。     

四丁基溴化铵相变蓄冷材料热物性实验研究

通过实验对四丁基溴化铵(TBAB)溶液的蓄冷结晶过程进行了测试,结果表明TBAB溶液的凝固温度随其浓度的改变而改变,在25%~45%的浓度范围内,其凝固温度位于5.8~9.3℃范围内.选取相变温度适宜、相变过程稳定、浓度为40%的TBAB溶液,向其添加硼砂成核剂,测试其相变温度和相变潜热,测试结果表明质量浓度为2%的硼砂在不影响TBAB溶液凝固温度的情况下可以降低其结晶过冷度2.4℃.采用示差扫描量热仪(DSC)测试TBAB溶液的熔解潜热为187.030kJ/kg.因此TBAB溶液是一种高效的空调蓄冷材料.     

冷冻型复合相变蓄冷材料的制备与性能评价

提出自行研制的一种低温(-25～-23℃)复合相变材料。该材料由氯化钠作为主储能剂,碳酸钾与氯化钾作为降温剂,并且筛选合适的成核剂及防相分离剂进行复合。样品的热物理性能(相变温度、相变潜热等)和热循环性能通过差示扫描量热仪(DSC)来表征;过冷度和热循环稳定性通过温度记录仪表征。结果表明:制备的两种蓄冷剂的相变温度为-25～-23℃,相变潜热200J/g以上,过冷度较小且循环100次后不会出现相分离现象。     

平板蓄冷器蓄冰过程试验研究

在自行研制的冰蓄冷试验装置上研究了平板内的蓄冰过程, 得出了载冷剂进出口温度和蓄冷剂温度随时间的变化规律; 对冰蓄冷过程进行了成核研究, 通过添加人工成核剂可减少冰蓄冷过程的过冷度,从而提高蓄冰主机的效率。     

平板蓄冷器蓄冰过程试验研究

本文在自行研制的冰蓄冷试验装置上研究了平板内的蓄冰过程, 得出了载冷剂进出口温度和蓄冷剂温度随时间的变化规律, 并对冰蓄冷过程进行了成核研究, 通过添加人工成核剂可减少冰蓄冷过程的过冷度, 从而提高蓄冰主机的效率。     

超声波优化相变蓄冷材料的研究进展

目的 为通过超声波方式解决过冷度高、蓄冷时间慢、稳定性差及成核慢等问题提供一些研究思路.方法 阐述3种常见的超声波装置(外置式、内置式、壁式)及其特性,介绍近年来国内外学者将超声波技术应用于相变蓄冷材料的研究进展,总结超声波对过冷度、二次结晶、成核速率、生长速率及稳定性等方面的影响.结果 超声波既能改善相变蓄冷材料的缺点又不影响其潜热,是相变蓄冷领域的一门新技术.结论 在实验研究基础上,推导建立超声波优化性能模型、寻找更加优化的超声方法、加强超声波的应用以及超声波技术对高温蓄冷材料的影响是今后研究的重点.     

平板蓄冷器蓄冰过程试验研究

本文在自行研制的冰蓄冷试验装置上研究了平板内的蓄冰过程,得出了载冷剂进出口温度和蓄冷剂温度随时间的变化规律,并对冰蓄冷过程进行了成核研究,通过添加人工成核可减少冰箱冷过程的过冷度,从而提高蓄冰主机的效率。     

平板蓄冷器蓄冰过程试验研究

本文在自行研制的冰蓄冷试验装置上研究了平板内的蓄冰过程,得出了载冷剂温度和蓄冷剂温度随时间的变化规律,并对冰蓄冷过程进行了研究,通过添加人工成核剂可减少冰蓄冷过程的过冷度,从而提高蓄冰主机的效率。     

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.     

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.     

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.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Effect of Permeable Crystalline Material on Steel Reinforcement Corrosion of Concrete

Permeable crystalline materialcan permeate into pores and cracks of concrete and catalyze the reaction between Ca(OH) 2and unhydrated cement to generate a great quantity needle non-soluble crystals, which can stop up the pores and cracks of concrete, and increase the impermeability of concrete. This paper reported the results of a study conducted to evaluate steel reinforcement corrosion of concrete specimens uncoated and coated with permeable crystalline material as well as mixed with the permeable crystalline material. The properties evaluated for corrosion test were water impermeability, water absorption, compressive strength and potential. The results of water impermeability, water absorption, compressive strength clearly showed that the permeable crystalline material could prohibit water, any soluble salts and moisture from penetrating the concrete to cause corrosion, leaking, and other problems, and it did increase the compressive strength, which was favorable for protection of corrosion of reinforcing steel. Moreover, it was concluded from the potential-time curve that the steel reinforcement of uncoated specimen was in the state of activation whereas that of other specimens coated and mixed with the permeable crystalline material was in the state of inactivation. Above all, it was indicated that the permeable crystalline materialis very effective to protect the steel reinforcement of concrete from corrosion.