捻陷、阻捻和假捻概念的统一

本文对传统的捻陷和阻捻概念进行了深入分析,认为捻陷才是真正起阻捻作用的。在此基础上提出可正确评价捻陷和阻捻程度的指标系数,阻捻系数和增捻系数。在对假捻的特点进行深入分析的基础上,指出传统的捻陷和阻捻实质上就是假捻,其捻陷点和阻捻点就是假捻点,产生捻陷和阻捻的阻力矩就是假捻力矩。因此,可用分析假捻的方法分析传统的捻陷和阻捻,从而可以简化对各种加捻现象的分析。     

如何减小强捻品种的捻丝断头率

澡巾品种已在我市的各丝绸厂家大量上机，此品种是利用纬丝的左右自强捻来形成织物的刍效应。由手捻度要求较大，因此，对捻丝机的需求量也较大。在劳动力和捻丝设备较紧张的情况下，如何最大限度地发挥捻丝机的生产效率，已成为各丝绸厂家的一个主要问题。对此提出一些见解，以供参考。丝纤维在抢丝机上加捻的过程也是丝纤维扭转、弯曲和拉伸的过程。丝纤维加捻后，增加了纤维的压力，及丝线中纤维相对滑移的阻力，从而增加了丝线的强力。随着捻度的增加，纤维的扭转角逐渐增加，纤维的扭转应力增大，脆性增加。在超过临界捻度系数之后，丝…     

对双捻机捻制过程的分析

规范了观察双捻机飞轮旋转方向与产品捻向的方法；分析了捻制过程中捻距的变化规律，对认识、掌握、使用双捻机及提高捻制质量很有必要。     

捻陷,阻捻和假捻概念的统一

本文对传统的捻陷和阻捻概念进行了深入分析，认为捻陷才是真正起阻捻作用的。在此基础上提出可正确评价捻陷和阻捻阻程度的指标系数，阻捻系数和增捻系数，在对假捻的特点进行深入分析的基础上，指出传统的捻陷和阻捻实质上就是假捻，其捻陷和阻捻点是假捻点，产生捻陷和阻捻的阻力矩就是假捻力矩，因此，可用分析假捻的方法分析传统的捻陷和阻捻。从而可简化对各种加捻现象的分析。     

转杯纺假捻盘捻陷作用分析

因关于转杯纺假捻盘的阻捻及捻陷作用的研究尚存争议,为此,在分析转杯纺假捻盘两段纱条的运动以及建立加捻区的捻度变化模型的基础上,对假捻盘的阻捻及捻陷作用进行系统地研究。首先,定义了纱条的公转运动以及自转运动的概念,经分析认为假捻盘存在捻陷作用,但不存在阻捻作用。之后,制作了实验装置,采用模拟实验的方法进一步研究了假捻盘的捻陷作用,得到了捻陷作用发生时纱条的捻度传递曲线。研究结果表明,随着纱条张力的增大,捻陷作用不易发生。     

不同捻向单纱并捻的工艺实践

为了适应市场不同的消费需求 ,我公司将精梳纯棉Ｓ捻纱和Ｚ捻纱并捻 ,开发了ＣＪ 1 8 5ｔｅｘ× 2股线 ,产品风格独特 ,主要用于针织物的生产 ,具有一定的市场价值。1　原料选择为使ＣＪ 1 8 5ｔｅｘ× 2股线具有良好的丝光效果 ,在配棉上选择了成熟度高、短绒率低的高品级细绒棉。原棉的主要物理指标为 :等级 1 .5 0 ,细度 1 .91ｄｔｅｘ ,主体长度 2 9.2 0ｍｍ ,短绒率1 2 78% ,成熟度 1 .78。2　产品特点2 .1　ＣＪ 1 8 5ｔｅｘ× 2股线的结构由Ｓ捻单纱与Ｚ捻单纱并合的Ｓ捻ＣＪ 1 8 5ｔｅｘ× 2股线形成了以Ｓ捻纱为轴、Ｚ捻纱缠绕在…     

自捻纺纱机结构介绍

本文简要介绍了自捻纺纱与环锭纺纱相比的优缺点,详细介绍了自捻纺纱机的结构。     

微分几何在不同捻法钢丝绳允许最多可见断丝数应用

钢丝绳使用过程中,为保证使用安全,均会限制钢丝绳不同使用工况条件下的最多可见断丝数。通过微分几何建立二次螺旋钢丝在钢丝绳中的空间坐标方程;借助研究二次螺旋钢丝曲率随其绕钢丝绳轴线旋转角的变化周期,从图像上、理论上解释了钢丝绳使用规范规定同向捻时允许最多可见断丝数与交互捻时存在大约1∶2这一相对固定的比例关系的合理性。     

高速缝纫线捻系数,捻比值的工艺实践

我厂生产的14．76XZtex、Z捻向纯涤纶线是一种用于高速缝纫的特殊用线，具有强力高、均匀度好等特点，但手感和光泽还不尽人意。为此，在生产过程中，对此问题作了一些探索，并取得了一定效果，现介绍如下。一、捻系数、捻比值对股线强力、手感及光泽的影响双股线在理论上当股线和单纱的捻比k＝QO1．414时，股线能获得最高强力，但此时的光泽和手感性能差。如要求股线的光泽与手感好，则理论上当于一O．7O7时，外层纤维轴向性最好，因而光泽好，但此时强力差。为获得具有一定强力而又有良好光泽与手感的股线，我们对纱线的捻系数、捻比值…     

管式捻股机过捻器的设计

在ＧＧ ６／１６５、ＧＧ １２／１６５型管式捻股机压线模后增设可变换过捻比过捻器装置，结合后辊轮变形器，较好地消除了捻制钢丝股（绳）的弹性应力，保证股（绳）的不松散性，尤其适用于捻制相应结构的钢帘线和拉筋用镀锌钢丝绳。     

Bacterial populations on teat ends of dairy cows housed in free stalls and bedded with either sand or sawdust

The main objectives of the experiment were: 1) to compare bacterial populations of mastitis-causing organisms on the teats of lactating dairy cattle housed on sand and sawdust bedding and, 2) to examine the relationship between bacterial counts present in the 2 bedding types with those on teat ends. Sixteen lactating Holstein cows were housed on either sand or sawdust-bedded free stalls using a crossover design with 3 wk per bedding type. Bedding samples were collected on d 0 (prior to animals lying on the bedding), 1, 2, and 6. Teat ends were sampled prior to the morning milking on d 1, 2, and 6. All samples were analyzed to determine coliform, Klebsiella spp., and Streptococcus spp. populations. There were 2 times more coliforms and 6 times more Klebsiella bacteria on teat ends of cows housed on sawdust compared with those housed on sand. In contrast, there were 10 times more Streptococcus spp. bacteria on teat ends of cows when housed on sand compared with sawdust. In both sawdust and sand bedding, coliforms, Klebsiella and Streptococcus counts increased over each experimental week, although patterns varied with bedding and bacteria type. Bacterial counts on teat ends were correlated with bacterial counts in sawdust (r = 0.47, 0.69, and 0.60 for coliforms, Klebsiella spp., and streptococci, respectively) and in sand (r = 0.35 for coliforms and r = 0.40 for Klebsiella spp.). In conclusion, coliforms and Klebsiella spp. on teat ends were more numerous when cows were housed on sawdust bedding, but Streptococcus spp. were more numerous on teat ends of cows housed on sand.     

基于多物理场有限元法的热铆结构设计与优化

基于多物理场有限元分析方法对热铆结构进行了电-热-结构的耦合分析。首先研究了热铆结构的材料选型,发现金属压头采用黄铜比采用不锈钢,其表面温度高10℃左右;塑料护套采用PTFE比采用PA6,其表面温度低15℃左右。为此,考虑黄铜金属压头和PTFE塑料护套的组合,进一步进行了热铆结构的尺寸优化,优化后热铆结构成本大大下降,热效率大幅提高,并能满足强度要求。     

High-quality forage can replace concentrate when cows enter the deposition phase without negative consequences for milk production

Mobilization and deposition in cows are different strategies of metabolism; hence, the aim was to study the possibility of reducing the crude protein (CP) supply during deposition to limit the use of protein supplements and minimize the environmental impact. A total of 61 Jersey and 107 Holstein cows were assigned to 4 mixed rations in a 2 × 2 factorial design with 2 concentrate to forage ratios (CFR) and 2 CP levels: high CFR (40:60) and recommended CP [16% of dry matter (DM); HCFR-RP], high CFR (40:60) and low CP (14% of DM; HCFR-LP), low CFR (30:70) and recommended CP (16% of DM; LCFR-RP), and low CFR (30:70) and low CP (14% of DM; LCFR-LP), where RP met the Danish recommendations. Cows were fed concentrate in an automatic milking unit. After calving, cows were fed HCFR-RP until entering deposition, defined as 11 kg (Jersey) or 15 kg (Holstein) of weight gain from the lowest weight after calving. Subsequently, cows either remained on HCFR-RP or changed to one of the other mixed rations. Comparing strategies during wk 9 to 30 of lactation showed higher dry matter intake (DMI) of mixed ration on HCFR compared with LCFR and on RP compared with LP. The DMI of the concentrate was higher on LCFR than on HCFR and higher on LP than on RP, resulting in overall higher DMI on HCFR and RP than on LCFR and LP. Crude protein intakes were higher on RP than on LP and starch intakes were higher on HCFR than on LCFR. Intakes of neutral detergent fiber tended to be higher on LCFR than on HCFR. Intakes of net energy for lactation were affected by CFR and CP level, with a higher intake on HCFR and RP than on LCFR and LP. No interactions were found between CFR and CP level for any feed intake variables. Yields of milk and energy-corrected milk were higher on RP than on LP, with no difference in yield persistency after the ration change. Milk composition did not differ among strategies but the protein to fat ratio was higher on HCFR than on LCFR and tended to be lower on RP than on LP. Differences in fatty acid composition were small, and de novo synthesis was high (>60%). Energy efficiency was higher on LCFR than on HCFR and no interaction with breed or parity was found. The N efficiency was higher on LP than RP, but with an interaction with breed due to lower N efficiency in Jersey than Holstein cows on HCFR-RP but higher N efficiency in Jersey than Holstein on LCFR-LP. In dairy production, concentrate in the mixed ration can be substituted with high-quality forage during deposition without negative effects on milk yield and composition when a sufficient CP level is ensured.     

茶多酚对羊毛媒染性能的影响

研究了茶多酚(TP)在羊毛织物上的媒染性能,用后媒法使硫酸亚铁和硫酸铜与茶多酚络合,分别探讨了pH值、温度和时间对茶多酚吸尽率及染色深度的影响;用预媒、同浴和后媒3种方式探讨了茶多酚及金属离子浓度对茶多酚吸尽率及染色深度的影响,并对染后织物进行了牢度测试。结果表明:羊毛织物经硫酸亚铁和硫酸铜媒染分别呈紫灰色和黄棕色,在茶多酚TP-98用量5%(owf)、pH值4.1、90℃时浸渍60 min后进行媒染处理,可达到中色,并具有良好的色牢度。耐洗、耐摩擦和耐光牢度均在3级以上,沾色牢度可达到5级;铜离子络合的耐洗变色和耐光牢度均好于亚铁离子。     

桑叶染色液提取法与染色性能

 为了探索提取方法和提取剂对桑叶染色液染丝绸的效果,采用沸水浴与微波法提取桑叶染色液,结果表明:染色液中的黄酮含量及对丝织物的上染率均以微波法较高。采用微波提取法,通过正交试验研究提取剂对上染率和色光的影响,结果表明对上染率影响最大的是表面活性剂用量,其次为NaOH浓度,再次为表面活性剂种类;对色光影响的次序是NaOH浓度大于表面活性剂用量和种类。采用微波提取法并在NaOH提取剂中加入表面活性剂的桑叶染色液染色效果较好。     

乌头总生物碱贴片皮肤安全性的研究

目的观察乌头总生物碱贴片对动物皮肤的毒性作用。方法用健康新西兰兔进行皮肤单次及多次给药刺激性实验;用健康豚鼠进行皮肤过敏性实验。结果乌头总生物碱贴片中剂量组单次给药时未见对新西兰兔完整皮肤有刺激性反应,对破损皮肤有轻度刺激性;多次给药对兔完整皮肤无刺激反应,对破损皮肤有中度刺激反应。但停药后刺激反应消失,皮肤恢复正常。乌头总生物碱贴片中剂量组对豚鼠完整皮肤无致敏作用。结论乌头总生物碱贴片皮肤局部用药有较好的安全性,为临床应用提供了安全性保证。乌头总生物碱贴片的处方合理,制备工艺可靠。     

Whole-genome association study for milk protein composition in dairy cattle

Our objective was to perform a genome-wide association study for content in bovine milk of α_S1-casein (α_S1-CN), α_S2-casein (α_S2-CN), β-casein (β-CN), κ-casein (κ-CN), α-lactalbumin (α-LA), β-lactoglobulin (β-LG), casein index, protein percentage, and protein yield using a 50K single nucleotide polymorphism (SNP) chip. In total, 1,713 Dutch Holstein-Friesian cows were genotyped for 50,228 SNP and a 2-step association study was performed. The first step involved a general linear model and the second step used a mixed model accounting for all family relationships. Associations with milk protein content and composition were detected on 20 bovine autosomes. The main genomic regions associated with milk protein composition or protein percentage were found on chromosomes 5, 6, 11, and 14. The number of chromosomal regions showing significant (false discovery rate <0.01) effects ranged from 3 for β-CN and 3 for β-LG to 12 for α_S2-CN. A genomic region on Bos taurus autosome (BTA) 6 was significantly associated with all 6 major milk proteins, and a genomic region on BTA 11 was significantly associated with the 4 caseins and β-LG. In addition, regions were detected that only showed a significant effect on one of the milk protein fractions: regions on BTA 13 and 22 with effects on α_S1-CN; regions on BTA 1, 9, 10, 17, 19, and 28 with effects on α_S2-CN; a region on BTA 6 with an effect on β-CN; regions on BTA 13 and 21 with effects on κ-CN; regions on BTA 1, 5, 9, 16, 17, and 26 with effects on α-LA; and a region on BTA 24 with an effect on β-LG. The proportion of genetic variance explained by the SNP showing the strongest association in each of these genomic regions ranged from <1% for α_S1-CN on BTA 22 to almost 100% for casein index on BTA 11. Variation associated with regions on BTA 6, 11, and 14 could in large part but not completely be explained by known protein variants of β-CN (BTA 6), κ-CN (BTA 6), and β-LG (BTA 11) or DGAT1 variants (BTA 14). Our results indicate 3 regions with major effects on milk protein composition, in addition to several regions with smaller effects involved in the regulation of milk protein composition.     

用气相色谱法预测挥发性有机试剂的沸点

根据不同结构基团的挥发性有机试剂在不同极性气相色谱柱上的保留行为,用多元线性回归(MLR)方法,建立了挥发性有机试剂沸点与不同极性色谱柱上保留时间之间的关系模型,并根据各模型相关系数与概率值定量说明了模型中不同参数引入时的统计意义.结果表明,与单一极性色谱柱上的保留时间相比,采用不同极性色谱柱上的保留时间,可以更好地预测有机试剂的沸点,并且更具统计学意义.     

Addition of glycerol to lactating cow diets stimulates dry matter intake and milk protein yield to a greater extent than addition of corn grain

The objective of this study was to determine if the addition of glycerol to the diet of dairy cows would stimulate milk protein yield in the same manner as the addition of corn grain. Twelve multiparous lactating dairy cows at 81 ± 5 d in milk were subjected to 3 dietary treatments in a replicated 3 × 3 Latin square design for 28-d periods. The diets were a 70% forage diet considered the basal diet, the basal diet with 19% ground and high-moisture corn replacing forages, and the basal diet with 15% refined glycerol and 4% added protein supplements to be isocaloric and isonitrogenous with the corn diet. Cows were milked twice a day and samples were collected on the last 7 d of each period for compositional analysis. Within each period, blood samples were collected on d 26 and 27, and mammary tissue was collected by biopsy on d 28 for Western blot analysis. Dry matter intake increased from 23.7 kg/d on the basal diet to 25.8 kg/d on the corn diet and 27.2 kg/d on the glycerol diet. Dry matter intake tended to be higher with glycerol than corn. Milk production increased from 39.2 kg/d on the basal diet to 43.8 kg/d on the corn diet and 44.2 kg/d on the glycerol diet. However, milk yield did not differ between corn and glycerol diets. Milk lactose yields were higher on the corn and glycerol diets than the basal diet. Milk fat yield significantly decreased on the glycerol diet compared with the basal diet and tended to decrease in comparison with the corn diet. Mean milk fat globule size was reduced by glycerol feeding. Milk protein yield increased 197 g/d with addition of corn to the basal diet and 263 g/d with addition of glycerol, and the glycerol effect was larger than the corn effect. The dietary treatments had no effects on plasma glucose concentration, but plasma acetate levels decreased 27% on the glycerol diet. Amino acid concentrations were not affected by dietary treatments, except for branched-chain amino acids, which decreased 22% on the glycerol diet compared with the corn diet. The decreases in plasma acetate and branched-chain amino acid concentrations with glycerol and the larger effects of glycerol than corn on milk protein and fat yields suggest that glycerol is more glucogenic for cows than corn grain.     

纤维表面木素含量对纸页强度的影响

本文用CTMP分别与漂白针叶木硫酸盐浆和漂白阔叶木硫酸盐浆配抄纸页,用原子力显微镜和X射线光电子能谱仪从微观角度研究了纤维表面木素含量对纸页强度的影响。研究表明化学浆纤维表面存在大量的微细纤维,而CTMP纤维表面覆盖有颗粒状木素、抽出物。纤维表面木素含量随打浆程度提高而降低,混合纤维表面木素含量与浆料的配比存在线性关系。受纤维表面木素浓度的影响,随CTMP配比增加,纸页的抗张指数和层间结合强度降低。