微生物源生物保鲜剂对水产品腐败菌作用机制研究进展

目的了解微生物源生物保鲜剂对水产品腐败菌作用的研究现状,延长水产品的贮藏货架期。方法分析常见水产品特定腐败菌种类、生物保鲜剂分类与主要优缺点,在此基础上,分别阐述乳酸链球菌素、ε-聚赖氨酸、乳酸菌、双歧杆菌等常用微生物源生物保鲜剂的抑菌机理与研究现状,提出其存在的问题和改进建议,并对微生物源生物保鲜剂的发展前景进行展望。结论微生物源生物保鲜剂与其他生物保鲜剂或保鲜技术相结合,能有效提高抑菌效果,发展前景广阔。     

氯杀菌剂在食品加工中的应用及抑菌建模研究进展

目的为研究与拓展氯杀菌剂在食品加工中的应用提供一定的思路与理论参考。方法综述氯杀菌剂在食品微生物控制中的应用、抑菌机理及其抑菌建模研究进展,并对其发展前景予以展望。结果氯杀菌剂因具有广谱杀菌、杀菌作用强、相对安全高效等优点,被广泛应用于食品加工中,以保证食品的微生物安全。氯杀菌剂的抑菌机理尚不完全明晰,针对微生物单细胞水平的氯杀菌剂抑菌动力学研究也相对较少。结论氯杀菌剂在食品加工领域的发展潜力巨大,探明其抑菌机理并结合预测微生物学相关理论,可以更好地评估氯杀菌剂对食源性致病菌的抑制作用,更科学地利用氯杀菌剂以保证食品的微生物安全性。     

精油微胶囊在食品保鲜中的应用研究进展

目的 综述精油微胶囊在食品保鲜领域的研究进展,为进一步开发精油微胶囊在食品保鲜中的应用提供科学的研究基础.方法 归纳近几年制备精油微胶囊的方法及其特点,简要介绍微流控法、反向分散凝胶法、层层自组装法及电喷雾法.总结精油微胶囊在食品保鲜中的应用方式以及在果蔬、冷鲜肉制品、加工制品、粮食作物等方面的应用研究.结果 微胶囊技术可以扩大精油在食品工业中的应用,精油微胶囊作为新型的天然保鲜剂用于食品贮藏中能抑制微生物生长,延长食品的货架期.结论 精油微胶囊在食品保鲜领域有较大发展潜力.     

金枪鱼生物保鲜技术的研究进展

目的 综述生物保鲜剂在金枪鱼贮藏中的研究现状。方法 首先分析金枪鱼贮藏过程中常见的腐败微生物, 其次介绍抗氧化生物保鲜剂、 抑菌生物保鲜剂、 复合保鲜剂在金枪鱼保鲜中的应用现状。结果 金枪鱼贮藏过程中常见的腐败微生物为假单胞菌、 腐败希瓦氏菌等, 生物保鲜剂的复合使用以及与气调包装技术结合可增加保鲜效果, 延长货架期。结论 生物保鲜, 尤其是复合保鲜剂以及生物保鲜剂与其他物理保鲜技术相结合在金枪鱼保鲜中极具发展潜力。     

茶多酚可降解复合膜在食品保鲜中的应用研究进展

目的 介绍茶多酚良好的抗氧化性、抑菌性,综述国内外将茶多酚与可降解成膜基材复合后应用于食品保鲜的研究进展,为后续研究提供基础。方法 通过对国内外研究现状和研究成果的综述,介绍茶多酚的保鲜机理及与可降解成膜基质复合后在食品保鲜（肉类、蔬菜类、水果类等）方面的具体应用,并分析茶多酚的加入对复合膜保鲜效果的影响。结论 从发展趋势来看,可降解食品保鲜材料必将拥有广阔的发展前景。茶多酚的添加虽使得可降解复合膜的保鲜效果大大增加,但国内外在茶多酚复合保鲜材料方面的研究形式相对较单一,多以复合膜或者膜液形式进行保鲜。利用微胶囊技术与茶多酚复合保鲜材料相结合制备保鲜剂,既能够更好地控制保鲜剂的使用量,又能避免直接与食品过多接触,是一个值得尝试的新思路。     

苯乳酸在食品保鲜中的应用研究进展

目的 介绍苯乳酸的抑菌机制,以及与微酸性电解水、醋酸和乳酸链球菌素的协同抗菌作用,为苯乳酸在食品保鲜中的应用提供一定的思路和依据。方法 概述苯乳酸的理化性质、制备方法,以及对不同微生物的抑菌活性和机制,总结苯乳酸在肉制品、果蔬、水产品等保鲜领域的应用研究进展,并对现有研究的局限性和今后的研究方向进行讨论。 结果 苯乳酸通过破坏微生物的细胞结构,干扰DNA合成和蛋白质合成,从而抑制其生长,与微酸性电解水、醋酸和乳酸链球菌素协同处理可显著增强抑菌效果。结论 苯乳酸对细菌和真菌具有广谱抑菌性,与其他抑菌剂有协同促进作用,在食品保鲜领域具有广阔的应用前景。     

茶多酚抑菌机理及在水产品保鲜中的应用进展

目的 随着人们对食品安全问题的重视,探究茶多酚的作用机制并将其用于水产品保鲜现已成为研究热点之一.方法 在介绍茶多酚的化学组成和主要作用机制的基础上,阐述茶多酚在水产品保鲜中的应用研究进展,提出存在的问题和解决方法,展望茶多酚在水产品保鲜领域的发展前景.结果 茶多酚具有良好的抗氧化性和抑菌活性,作为一种来源广泛、天然安全的生物保鲜剂,相较于化学合成的保鲜剂,更能满足人们追求绿色健康食品理念的要求.结论 只有充分挖掘茶多酚的优势,结合新型保鲜剂或处理方式,才能更好地发挥茶多酚在水产品保鲜方面的作用,使其发展前景更加广阔.     

舰船微生物腐蚀研究进展

在舰船的舱底积水和海水管系中，微生物腐蚀是重要的腐蚀形式之一。在众多的微生物中以硫酸盐还原菌（SRB）的腐蚀最为严重，主要表现为微生物的生长代谢在金属表面形成生物膜，改变了生物膜内的微环境，其代谢产物与金属基体相互作用，加速了金属的腐蚀过程．文中从微生物的生理学、腐蚀机理等角度，对舰船材料的腐蚀危害、微生物腐蚀研究方法和腐蚀防治措施以覆微生物腐蚀的近期研究状况等几个方面进行了综述，并展望了微生物腐蚀研究的发展趋势．     

食品接触表面食源性致病菌生物膜形成及控制研究进展

目的 综述食源性致病菌在食品接触表面形成生物膜的安全性及其控制措施,为解决食品接触表面食源性致病菌形成生物膜的危害问题提供参考.方法 归纳阐述近年来国内外食品接触表面形成食源性致病菌生物膜的危害问题,重点分析生物膜的形成机制、预防和控制措施,以及未来的发展方向.结果 食源性致病菌在食品接触表面形成粘附力大、抗逆性高、适应性广、耐药性强的生物膜结构,使用常规的物理性、化学性生物膜清除方法无法完全去除;广谱微生物源性抗生物膜剂、抗菌包装材料和天然食品级化学杀菌剂具有优良的裂解性、特异性、无毒性、环保性和抗菌性等特点,已成为生物膜清除和控制的有效资源.结论 天然抗菌活性物质、抑菌包装材料和具有生物活性的抗生物膜剂已逐步取代传统的物理性、化学性生物膜清除方法,成为有效保障食品工业生产、消费者食品食用安全的新途径之一.     

紫外线杀菌技术在鲜切果蔬保鲜中的应用研究进展

目的 通过介绍紫外线杀菌技术在鲜切果蔬保鲜中的应用研究进展,以期为其在鲜切果蔬保鲜中的进一步研究与应用提供参考.方法 综述国内外长波紫外线、中波紫外线和短波紫外线对鲜切果蔬品质、生理代谢相关酶活性以及微生物的影响.结果 紫外线杀菌技术作为一种绿色安全的鲜切果蔬保鲜技术,可以有效抑制鲜切果蔬中微生物的生长繁殖,减缓鲜切果蔬生理代谢,防止褐变,延迟衰老,并延长鲜切果蔬货架期,且不会对鲜切果蔬的风味和口感产生影响.结论 在目前重视食品快捷和安全的趋势下,紫外线杀菌技术因其具有安全方便、对环境友好等特点,现已在鲜切果蔬保鲜中得到广泛应用,并具有重要的发展前景.     

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.……     

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.     

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 ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.