共查询到20条相似文献,搜索用时 185 毫秒
1.
2.
3.
4.
5.
介绍大跨度悬索桥主缆索股制造技术现状,通过对盘条索氏体化处理、提高钢丝强度等级、采用锌铝合金镀层替代锌镀层、改进制索工艺,对索夹抗滑移性能进行研究,探索出适合大跨度悬索桥主缆的1 860 MPa等级锌铝合金镀层钢丝索股制作成套技术,并成功应用于国内外多座大跨度悬索桥。 相似文献
6.
7.
8.
9.
《金属制品》2017,(5)
锌铝合金镀层钢丝在国内桥梁缆索上的应用已经开始。介绍GB/T 17101《桥梁缆索用热镀锌钢丝》修订中讨论的几个技术问题:考核钢丝扭转指标是选择原材料有效且具有可操作性的方法;锌铝合金镀层较纯锌更软、更容易发生悬索桥主缆索夹滑移,在不降低镀层防腐寿命的前提下对镀层指标进行调整,主缆钢丝锌铝合金镀层面质量推荐采用260 g/m2;为得到理想的锌铝共晶合金镀层,推荐镀层铝质量分数为4.2%~7.2%;由于锌铝合金化学活性大于纯锌,锌铝镀层硫酸铜试验要求不小于2次(每次45 s),避免了因过高的硫酸铜试验指标导致的镀层厚度增加,从而减少了悬索桥主缆索夹滑移的可能性。 相似文献
10.
介绍1 960 MPa主缆单元索股制作的关键工序,对标准丝和单元索股的制作精度进行分析,理论上标准丝制作精度不小于L/15 000,单元索股制作精度不小于L/12 000。根据理论计算结果,模拟实桥放索试验进行验证,在编索过程中,3 070 m长的标准钢丝在标记处最大相对偏差为175 mm,相对长度精度为1/17 543,试验结果与理论分析一致。放索时定型包带无损坏,钢丝无散丝、弯折和断丝,整根索股扭转角度在±90°内;少量鼓丝也在收卷过程中因索股受力而消失。放索试验时,索股长3 070 m的标准钢丝在标记处的最大相对偏差为235 mm,相对长度精度为1/13 064,满足主缆架设精度要求。 相似文献
11.
12.
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
13.
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
14.
15.
16.
17.
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
18.
19.
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
20.
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