涤棉织物柔软整理前后导湿透气性能变化分析

通过改变柔软剂使用量、处理温度等测试条件,测试织物整理前后导湿及透气性能的变化情况.测试结果表明:经过柔软整理后,涤棉织物的亲水性得到改善,织物的导湿性有了明显提高,芯吸高度增加,在织物中的完全渗透时间缩短.由于织物的密度、厚度及面密度在整理后有所增加,织物的透气性能略有下降.     

肉制品中动物源性成分DNA检测方法的研究进展

肉制品主要成分标识的真实性是全球重要的食品安全问题之一,特别是肉制品中动物源性成分的掺假和标识问题已引发全球关注。如何对肉制品中动物源性成分进行鉴定和标识已成为产品真实性鉴定的热点。基于DNA分子稳定性强的优点,DNA检测技术被广泛用于食品安全检测和监测诸多领域,体现出了灵敏度高、特异性强等优势。本文重点从动物源性检测的靶序列DNA选择和DNA分析技术研究2个方面,阐述了肉制品中动物源性成分定性、定量检测技术的研究和应用,并讨论动物源性成分定量分析的可能性,为我国实施动物源性成分量化监管提供思路。     

低质量分数结冷胶的流变性质

以低质量分数(0.01%～0.25%)结冷胶(gellangum)为研究对象,研究了结冷胶溶胶(质量分数为0.01%～0.04%)的流变性质,考察了Ca2+质量分数及胶质量分数对结冷胶凝胶(0.05%～0.25%)的凝胶强度的影响以及Ca2+与K+在促进凝胶的协同作用.结果表明,质量分数为0.01%～0.04%的结冷胶溶胶的流变学类型接近Cross模型,该体系具有剪切稀化性、触变性及屈服应力,且三者均随结冷胶质量分数的增大而增大.动态测量结果表明,上述溶胶是以弹性为主的粘弹性体系,弹性所占比例随结冷胶质量分数的增大而增大.结冷胶凝胶(质量分数为0.05%～0.25%)的凝胶强度随胶质量分数的增大而增大;随Ca2+质量分数的增大呈先增大后减小的变化规律,Ca2+的最适用量为200～280mg/kg.Ca2+与K+对促进结冷胶凝胶无协同作用.     

The cost-benefit of genomic testing of heifers and using sexed semen in pasture-based dairy herds

Recent improvements in dairy cow fertility and female reproductive technologies offer an opportunity to apply greater selection pressure to females. This means there may be greater incentive to obtain genomic breeding values for females. We modeled the impact of changes to key parameters on the net benefit from genomic testing of heifer calves with and without usage of sexed semen. This paper builds on earlier cost-benefit studies but uses parameters relevant to pasture-based systems. A deterministic model was used to evaluate the effect on net benefit due to changes in (1) reproduction rate, (2) genomic test costs, (3) availability of parent-derived breeding values (EBV_PA), and (4) replacement rate. When the use of sexed semen was included, we also considered (1) the proportion of heifers and cows mated to sexed semen, (2) decreases in conception rate in inseminations with sexed semen, and (3) the marginal return for surplus heifers. Scenarios with lower replacement rates and no availability of EBV_PA had the largest net benefits. Under current Australian parameters, the net benefit of genomic testing realized over the lifetime of genotyped heifers is expected to range from A$204 to A$1,124 per 100 cows for a herd with median reproductive performance. The cost of a genomic test, a perceived barrier to many farmers, had only a small effect on net benefit. Genomic testing alone was always more profitable than using sexed semen and genomic testing together if the only benefit considered was increased genetic gain in heifer replacements. When other benefits (i.e., the higher sale price of a surplus heifer compared with a male calf) were considered, there were combinations of parameters where net benefit from using sexed semen and genomic testing was higher than the equivalent scenario with genomic testing only. Using sexed semen alongside genomic testing is most likely to be profitable when (1) used in heifers, (2) the marginal return for selling surplus heifers (sale price minus rearing costs) is greater than A$400, and (3) conception rates of no more than 10 percentage points lower than those achieved using conventional semen can be realized. Net benefit was highly dependent on the marginal return. Demonstrating that the initial investment in genomic testing can be recouped within the lifetime of the heifers tested may assist in the development of extension messages to explain the value of genomic testing females at the herd level.     

An improved viscoelastic model for tufted carpet yarn

To overcome the problem that the existing mathematical model cannot characterize the viscoelastic properties of tufted carpet yarn completely and accurately, an improved viscoelastic model is built using the semi-empirical method. Using the test data of creep and stress relaxation, the parameters of the improved model are determined. Through the evaluation of fitting effect, the optimal mechanical model to characterize the viscoelastic properties of tufted carpet yarn is obtained. The results show that compared with the standard linear model, the improved model is more suitable to characterize viscoelastic mechanical properties of tufted carpet yarns, such as the creep and stress relaxation properties, which provides a solid theoretical foundation for analysis of vibration characteristics and dynamic tension control of tufted carpet yarn.     

Supplex纤维针织物的染色工艺探讨

根据Supplex纤维的特性,选择了活性染料对Supplex针织物进行染色。采用正交试验方法。分析了染料用量、染色浴比、染色时间等因素对染色质量的影响,探讨了最佳染色工艺。     

Risk-based approach to developing a national residue sampling plan for testing under European Union regulation for veterinary medicinal products and coccidiostat feed additives in domestic animal production

A ranking system for veterinary medicinal products and coccidiostat feed additives has been developed as a tool to be applied in a risk-based approach to the residue testing programme for foods of animal origin in the Irish National Residue Control Plan (NRCP). Three characteristics of substances that may occur as residues in food are included in the developed risk ranking system: Potency, as measured by the acceptable daily intake assigned by the European Medicines Agency Committee for Medicinal Products for Veterinary Use, to each substance; Usage, as measured by the three factors of Number of Doses, use on Individual animals or for Group treatment, and Withdrawal Period; and Residue Occurrence, as measured by the number of Non-Compliant Samples in the NRCP. For both Number of Doses and Non-Compliant Samples, data for the 5-year period 2008–12 have been used. The risk ranking system for substances was developed for beef cattle, sheep and goats, pigs, chickens and dairy cattle using a scoring system applied to the various parameters described above to give an overall score based on the following equation: Potency × Usage (Number of Doses + Individual/Group Use + Withdrawal Period) × Residue Occurrence. Applying this risk ranking system, the following substances are ranked very highly: antimicrobials such as amoxicillin (for all species except pigs), marbofloxacillin (for beef cattle), oxytetracycline (for all species except chickens), sulfadiazine with trimethoprim (for pigs and chickens) and tilmicosin (for chickens); antiparasitic drugs, such as the benzimidazoles triclabendazole (for beef and dairy cattle), fenbendazole/oxfendazole (for sheep/goats and dairy cattle) and albendazole (for dairy cattle), the avermectin ivermectin (for beef cattle), and anti-fluke drugs closantel and rafoxanide (for sheep/goats); the anticoccidials monensin, narasin, nicarbazin and toltrazuril (for chickens). The risk ranking system described is a relatively simple system designed to provide a reliable basis for selecting the veterinary medicinal products and coccidiostat feed additives that might be prioritised for residue testing.     

干法糊化对燕麦粉面团应力松弛特性的影响

采用挤压、蒸汽、微波及烘烤4种干法处理燕麦籽粒或燕麦粉,测定不同处理及不同糊化度燕麦粉面团的应力松弛特性。结果表明:挤压、蒸汽、微波及烘烤处理的燕麦粉糊化度分别为77.8%、39.3%、17.8%及13.7%。相对于其他糊化方法,挤压处理组面团的松弛时间、阻尼系数、残余应力最大,分别为60.90 s、3.70×10~6N·m~(-2)·s、9.39×104N·m-2;糊化度与燕麦粉面团的松弛时间、阻尼系数、残余应力均显著正相关(R=0.97、0.99、0.99;P0.05)。干法糊化显著提高了燕麦粉面团的黏性和结合力。     

国内外化学检测领域能力验证结果统计 方法的探讨

正确地选择和使用能力验证果统计方法对于能力验证的成功实施具有至关重要的作用。本文对国内外化学检测领域能力验证的参考指南进行检索,重点分析各指南或标准在指定值、能力评定标准差、能力统计量、图示法等能力验证结果统计关键环节的异同点。通过分析发现,不同的认证认可组织对于能力验证结果的统计方法及能力评定既相似又有各自的特点,这些组织制定的能力验证结果统计及能力评定准则大多以ISO/IEC17043、ISO 13528为基本依据进行编制,但又不完全相同,有不同程度的细化、扩展和限制。本文提供的检索资源及提炼的观点可以为我所以能力验证提供者身份首次组织实施能力验证提供理论参考,为能力验证统计人员正确选择和使用统计方法提供更多的信息和借鉴。