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人们常说:“象丝绸一样光滑”。用蚕儿吐出的银白色的丝制成的光亮、滑爽的丝织品,在古罗马曾是一种奢侈品,而今仍然如此。中国是丝绸之邦,早在新石器时代晚期,中国人就学会了栽桑养蚕,生产丝绸。在山西省夏县发现了丝绸生产的最早证据,那是一颗大约经历了6000~7000年的蚕茧化石。浙江省吴兴县出土的古代丝绸制品的残片,证明早在4500年前,长江流域就有了丝绸织造业。到了夏朝和商朝(公元前2100~1100年),养蚕已很普遍。许多玉石和青铜饰物 相似文献
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中国是世界蚕业的发源地,蚕丝业在中国有着数千年的历史,而蚕丝业教育直到鸦片战争之后才逐渐引起人们的重视,且发端于蚕业教育,1897年林启创建的蚕学馆正是这样一个例子。纺织丝绸教育由蚕学馆开始可谓是从无到有,从仅有两门专业课程到独立设置科系,再逐渐发展出完善的教学实践体系与养蚕系并重,是随着蚕业教育的完善而逐步兴起并发展壮大。经过百余年的风雨洗礼,蚕学馆现已发展成以纺织学科闻名全国的理工科大学——浙江理工大学。由此可见,蚕学馆的兴建对中国纺织丝绸教育的发展起到了举足轻重的作用。 相似文献
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一、世界蚕丝业的历史和现状 根据现存的记录和考古学家发掘出来的古代丝织品,表明中国是至少有5000年历史的丝绸工业的发源地。在一个相当长的时期内,只有中国生产丝绸,这是因为在养蚕技术的传播方面受到了种种限制。传说在公元前12世纪,丝绸第一次被带出中国,带到朝鲜。此外,丝绸奥秘通过丝绸之路传播到世界各地,使得一些国家建立起了蚕丝业。没有任何一种织物能与丝绸的华贵、雅致和美丽相媲美,因此,丝绸被誉为“纤维皇后”。 相似文献
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Figueroa-González I Quijano G Ramírez G Cruz-Guerrero A 《Journal of the science of food and agriculture》2011,91(8):1341-1348
Owing to their health benefits, probiotics and prebiotics are nowadays widely used in yogurts and fermented milks, which are leader products of functional foods worldwide. The world market for functional foods has grown rapidly in the last three decades, with an estimated size in 2003 of ca US$ 33 billion, while the European market estimation exceeded US$ 2 billion in the same year. However, the production of probiotics and prebiotics at industrial scale faces several challenges, including the search for economical and abundant raw materials for prebiotic production, the low-cost production of probiotics and the improvement of probiotic viability after storage or during the manufacturing process of the functional food. In this review, functional foods based on probiotics and prebiotics are introduced as a key biotechnological field with tremendous potential for innovation. A concise state of the art addressing the fundamentals and challenges for the development of new probiotic- and prebiotic-based foods is presented, the niches for future research being clearly identified and discussed. 相似文献
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常用消毒灭菌法及其机理与应用 总被引:3,自引:0,他引:3
介绍了采用消毒灭菌方法,有加热消毒法,紫外线辐射法和化学药剂消毒法。常用化学药剂有醛类、含氯消毒剂、醇类消毒剂以及高锰酸钾、生石灰等,阐释了消毒与灭菌两个概念的区别。 相似文献
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The objectives of the current study were to investigate the relationship between body condition score (BCS) and dairy form and changes in genetic parameters for BCS and dairy form within and across lactations and age. Body condition score and dairy form were obtained from the Holstein Association USA, Inc. Records were edited to include those cows classified between 24 and 60 mo of age and between 0 and 335 d in milk (DIM). A minimum of 20 daughters per sire and 15 cows per herd-classification visit were required. The dataset consisted of 135,178 records from 119,215 cows. Repeatability, multiple trait, and random regression models were used to analyze the data. All models included fixed effects for herd-classification visit, age within lactations 1, 2, and 3 or higher, and 5th-order polynomials for DIM. Random effects included sire and permanent environment for all models. Random regression models included age at classification nested within sire or DIM and lactation number nested within sire. Genetic variance for both BCS and dairy form was lowest in early lactation and highest in midlactation. Genetic correlations within and across lactations were high. The genetic correlation between DIM 0 in lactation 1 and DIM 305 in lactation 3 was estimated to be 0.77 for BCS and 0.60 for dairy form. The genetic correlation estimate between 30 mo of age at classification and 50 mo of age at classification was 0.94 for both dairy form and BCS. The repeatability models appeared to generate accurate evaluations for BCS or dairy form at all ages and stages of lactation. 相似文献
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A. FOSTER 《International journal of cosmetic science》1979,1(4):221-245
An historical reference is followed by a review of cosmetic colours’ regulations based on the EEC Directive with particular reference to the U.K. Cosmetic Products Regulations and their effect on formulation. Les reglementations des colorants pour cosmetiques 相似文献
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法国R.Stat公司活跃在导电纤维市场已有20年之久,但是,办公室雇员、宾馆客人、飞机乘客、在易爆炸环境中工作的人员、木材或纸浆工业操作人员、消防队员和军人,由于得益于R.Stat公司生产的导电纤维的保护,而免遭令人不舒服的电击,或者免遭火灾和爆炸的伤害,这些却无人知晓。 相似文献