中国铜管制造业现状及特点

文章概述了我国铜管生产行业的现状和电力、空调、冰箱、汽车、建筑等铜管主要消费市场的发展情况以及铜管的进出口贸易状况和发展趋势。     

浅析TP2铜管水平连铸高产生产线

本文讨论了铜管坯生产流程中所用的工频感应电炉、结晶器、牵引机等设备的参数和性能,并结合铜管坯的实际生产情况进行了阐述。同时强调了与铜管生产相关联设备的重要联系,对铜管生产线的选型具有实际指导作用,具有较强的实用性。     

延长方坯结晶器铜管使用寿命

本文分析了铜管设计、冷却水、连铸机设备及钢水等对方坯结晶器铜管使用寿命的影响。通过设备、工艺的改进和生产管理水平提升。铜管使用寿命得到了大幅度延长。     

水平连铸在铜管生产中的应用进展

主要概述了水平连铸法生产铜管的工艺流程、主要设备、基本原理和工艺技术;此外,还阐述了水平连铸法生产铜管的应用现状,并指出了未来水平连铸法生产铜管的发展方向。     

新型管式结晶器铜管的开发与应用

通过对管式结晶器铜管上口变形问题的分析、研究 ,开发出一种新结构的铜管 ,解决了影响结晶器铜管寿命的的一些难题 ,延长了其使用寿命 ,降低了生产成本     

精密铜管性能稳定性探究

内螺纹铜管质量的不稳定性使空调生产厂家在铜管的弯管过程中,出现各种不同的缺陷,针对影响精密内螺纹铜管性能稳定性的因素,以某企业生产实践的方法进行了初步研究,研究表明,铜管生产过程中的表面质量、机械性能均匀性及尺寸精度是影响铜管性能稳定性的主要因素。文中主要从这三方面进行了分析并提出了有效控制措施。     

国内内螺纹铜管生产技术与发展方向

本文介绍了国内内螺纹铜管的技术条件及生产现状，阐述了无缝内螺纹铜管和焊接内螺纹铜管的生产工艺，指出了内螺纹铜管的发展方向及市场前景。     

制冷空调用铜管质量标准现状

本文介绍了我国制冷空调用铜管的质量标准:GB/T17791-1999《空调与制冷用无缝铜管》、YS/T440-2001《内螺纹铜管》、GB/T1531-1994《铜及铜合金毛细管》以及《冰箱用高清洁度铜管》和《铜及铜合金无缝翅片管》的制订背景,分析了标准水平,提出了制冷空调用铜管在满足标准的同时,还要加强实物质量的提升。     

内螺纹铜管的齿型分类及发展方向

内螺纹铜管与普通铜管相比热交换效率显著提高，因此被广泛应用于节能、高效、小型化的制冷设备。随着内螺纹铜管成型技术的不断发展、改进、创新，开发出了各种不同齿型的产品。本文就国内外内螺纹铜管的发展方向做了简要的介绍。     

紫铜盘管中层外表氧化变色的机理分析及防治措施

一、前言紫铜盘管中层外表面氧化变色是铜管生产中常见的一种质量缺陷,它是指盘管的上下端面、内外侧面的铜管是光亮的,但当用户将外层的铜管使用1～2层或几层后,中间层的铜管的外表面产生了氧化变色(见图1)。这是一个带有普遍性的质量难题,众多铜管加工企业为此深感头痛。     

Standards of weight and height for Ayrshire, brown Swiss, and milking shorthorn heifers

To develop a modern appraisal of growth for Ayrshire, Brown Swiss, and Milking Shorthorn dairy heifers, data on heart girth and height at withers were collected from 1279 Ayrshire heifers (33 herds), 1819 Brown Swiss heifers (46 herds), and 565 Milking Shorthorn heifers (20 herds), ages 1 to 25 mo, in herds located throughout the US. Means and standard deviations were determined for height and heart girth for each month of age. Third-order regressions on age were fitted to the means to describe height and heart girth. Estimated mean height and heart girth at 6, 12, 18, and 24 mo, in centimeters, were for Ayrshire 98.7 and 118.4, 114.4 and 145.9, 122.8 and 163.2, and 127.6 and 176.4; for Brown Swiss 102.6 and 122.3, 199.4 and 151.3, 128.7 and 168.8, and 134.0 and 182.0; and for milking Shorthorn 98.0 and 119.4, 113.6 and 148.6, 122.6 and 166.6, and 127.7 and 179.9, respectively. These data can be useful to evaluate the heifer rearing program with respect to the growth rates of heifers on an individual farm.     

Antipneumococcal activities of RP 59500 (quinupristin-dalfopristin), penicillin G, erythromycin, and sparfloxacin determined by MIC and rapid time-kill methodologies

Previous time-kill studies have shown that RP 59500 is rapidly bactericidal against pneumococci. To extend these findings, the activities of RP 59500, its two components RP 57669 RP 54476, penicillin G, erythromycin and sparfloxacin against 26 penicillin-susceptible, 25 penicillin-intermediate, and 25 penicillin-intermediate, and 25 penicillin-resistant pneumococci were determined by the agar dilution MIC and the time-kill testing methodologies within 10 min (ca. 0.2 h) and at 1 and 2 h. Respective agar dilution MICs at which 90% of isolates are inhibited for penicillin-susceptible, -intermediate, and -resistant strains were as follows: penicillin G, 0.03, 1, and 4 micrograms/ml;RP 59500, 1, 1, and 1 microgram/ml; RP 57669, 8, 32, and 16 micrograms/ml; RP 54476, > 128, > 128, and > 128 micrograms/ml; erythromycin, 0.06, 2, and > 128 micrograms/ml; and sparfloxacin, 1, 0.5, and 0.5 microgram/ml. RP 59500 was equally active (MIC at which 90% of isolates are inhibited, 1.0 microgram/ml) against erythromycin-susceptible and -resistant strains. Time-kill testing results showed that only RP 59500 at one to four times the MIC killed pneumococci at 0.2 h; RP 59500 was also the most active compound at 1 and 2 h. By comparison, penicillin and sparfloxacin at one, two, and four times the MICs reduced the original inoculum by > or = 1 log at 2 h for 46, 80, and 95% and for 50, 72, and 86% of strains, respectively. The killing activity of RP 59500 was the same against erythromycin-susceptible and -resistant strains. RP 57669, RP 54479, and erythromycin were either inactive or bacteriostatic at 2 h. Of all drugs tested, RP 59500 yielded the most rapid killing.     

Sordarins: in vitro activities of new antifungal derivatives against pathogenic yeasts, Pneumocystis carinii, and filamentous fungi

GM 193663, GM 211676, GM 222712, and GM 237354 are new semisynthetic derivatives of the sordarin class. The in vitro antifungal activities of GM 193663, GM 211676, GM 222712, and GM 237354 against 111 clinical yeast isolates of Candida albicans, Candida kefyr, Candida glabrata, Candida parapsilosis, Candida krusei, and Cryptococcus neoformans were compared. The in vitro activities of some of these compounds against Pneumocystis carinii, 20 isolates each of Aspergillus fumigatus and Aspergillus flavus, and 30 isolates of emerging less-common mold pathogens and dermatophytes were also compared. The MICs of GM 193663, GM 211676, GM 222712, and GM 237354 at which 90% of the isolates were inhibited (MIC90s) were 0.03, 0.03, 0.004, and 0.015 microg/ml, respectively, for C. albicans, including strains with decreased susceptibility to fluconazole; 0.5, 0.5, 0.06, and 0.12 microg/ml, respectively, for C. tropicalis; and 0.004, 0.015, 0.008, and 0.03 microg/ml, respectively, for C. kefyr. GM 222712 and GM 237354 were the most active compounds against C. glabrata, C. parapsilosis, and Cryptococcus neoformans. Against C. glabrata and C. parapsilosis, the MIC90s of GM 222712 and GM 237354 were 0.5 and 4 microg/ml and 1 and 16 microg/ml, respectively. The MIC90s of GM 222712 and GM 237354 against Cryptococcus neoformans were 0.5 and 0.25 microg/ml, respectively. GM 193663, GM 211676, GM 222712, and GM 237354 were extremely active against P. carinii. The efficacies of sordarin derivatives against this organism were determined by measuring the inhibition of the uptake and incorporation of radiolabelled methionine into newly synthesized proteins. All compounds tested showed 50% inhibitory concentrations of <0.008 microg/ml. Against A. flavus and A. fumigatus, the MIC90s of GM 222712 and GM 237354 were 1 and 32 microg/ml and 32 and >64 microg/ml, respectively. In addition, GM 237354 was tested against the most important emerging fungal pathogens which affect immunocompromised patients. Cladosporium carrioni, Pseudallescheria boydii, and the yeast-like fungi Blastoschizomyces capitatus and Geotrichum clavatum were the most susceptible of the fungi to GM 237354, with MICs ranging from /=2 microg/ml. In summary, we concluded that some sordarin derivatives, such as GM 222712 and GM 237354, showed excellent in vitro activities against a wide range of pathogenic fungi, including Candida spp., Cryptococcus neoformans, P. carinii, and some filamentous fungi and emerging invasive fungal pathogens.     

Certification of nutrients in Standard Reference Material 1846: infant formula

In 1996, the National Institute of Standards and Technology (NIST) released Standard Reference Material 1846 (Infant Formula), which can be used as a control material for assigning values to in-house control materials and for validating analytical methods for measurement of proximates, vitamins, and minerals in infant formula and similar matrixes. The SRM was manufactured by preparing a spray-dried formula base containing fat, protein, carbohydrates, and minerals and then combining that formula base with a dry-blend vitamin premix that supplied the vitamins. The Certificate of Analysis for SRM 1846 provides assigned values for concentrations of proximates (fat, protein, etc.), vitamins, and minerals for which product labeling is required by the Infant Formula Act of 1980 and by the Nutrition Labeling and Education Act of 1990. These assigned values were based on agreement of measurements by NIST and/or collaborating laboratories. Certified values are provided for vitamins A (trans), E, C, B2, and B6 and niacin. Noncertified values are provided for solids, ash, fat, nitrogen, protein, carbohydrate, calories, vitamin D, delta-tocopherol, gamma-tocopherol, vitamin B1, vitamin B12, folic acid, pantothenic acid, biotin, choline, inositol, calcium, phosphorus, magnesium, iron, zinc, copper, sodium, potassium, and chloride. Information values are provided for iodine, manganese, selenium, and vitamin K.     

Threonine requirements of laying hens

In order to determine the Thr requirement of laying hens, two experiments were conducted using laying performance and plasma Thr concentration as parameters. At 29 and 39 wk of age, 100 and 600 laying hens in Experiments 1 and 2, respectively, with average BW and high egg production rate, were randomized, housed in individual cages, and given free access to water and experimental diets with five graded levels of Thr: 0.31, 0.39, 0.46, 0.54, and 0.61% for 21 d in Experiment 1 and diets with 0.31, 0.36, 0.41, 0.46 and 0.51% Thr for 58 d in Experiment 2. On the last day of the experiment, blood samples were taken for determination of plasma amino acid concentration. Feed intake and daily egg mass increased and then decreased linearly as dietary Thr increased. Plasma Thr increased slowly, then sharply with increasing dietary Thr levels. Using the broken-line model, the Thr requirements were estimated to be 0.425, 0.428, and 0.430% or 453, 456, and 458 mg/hen per d in Experiment 1 and 0.395, 0.404, and 0.400%, or 457, 467, and 462 mg/hen per d, in Experiment 2, for egg mass, feed efficiency, and plasma Thr concentration, respectively. These results indicate that the Thr requirements expressed as milligrams per hen per day as determined by plasma Thr concentration agree with those of laying performance.     

内蒙古桦树沟金矿综合找矿效果及意义

在1/5万察哈尔右翼前旗等四幅区域矿产地质调查的基础上,通过化探系统采集样品、地质填图和综合找矿方法发现了桦树沟金矿,并对金矿成矿提出了新的认识。野外地质研究发现,桦树沟矿区NE、近EW向断裂控制着异常展布及地表构造蚀变带和铁锰矿化体的延伸,围岩及矿化蚀变主要有硅化、钾化、绢云母化及沿裂隙充填的铁锰矿化和褐铁矿化。运用综合找矿方法筛选找矿靶区,将桦树沟异常面积从28.8 km²缩小到3.6 km²,有助于更好地找寻金矿床。采用水系沉积物和土壤测量方法对矿区异常元素进行了测试,并根据富集系数讨论富集成矿问题,结果显示：与成矿关系密切的桦树沟岩体强富集元素有Ag、Pb、Zn、As、Sb、W、Bi和Mo等,其围岩集宁岩群富集-强富集元素有Ag、Pb、Au、Cu、As、Sb、W和Mo等,表明岩浆活动为成矿提供了含矿热液,而热液又与围岩发生交代,导致金银等多金属在成矿有利部位富集成矿。结合1/1万地质填图、1/1万土壤测量等方法进一步开展异常检查评价,发现多个样品含量已达矿石边界品位,异常浓集中心及分带明显,经探槽工程揭露并圈定出2条金矿体,其分布特征、物质组成和控矿因素已基本查明,表明该区具有良好的找矿前景。     

重毒性铅污染土壤清洁高效修复研究进展

在介绍了铅元素污染背景、现状与危害的基础上,对土壤中铅的来源、赋存形式及其提取方法进行了详细介绍。结合土壤修复技术研究现状,对三大修复方法如物理、化学及生物修复法进行了系统综述,并从效率、适用性、经济性等方面评估了3种修复方法的优势与劣势,发现化学修复最适合重毒性铅污染治理。随之对化学淋洗法和固定化/稳定法作了详细介绍,探讨并评价了不同种类淋洗剂和固化剂的修复机制、修复效果、适用性和应用前景等。最后对未来重毒性铅污染土壤清洁高效修复提出了展望,修复方法应尽量减少对土壤的破坏;对高铅污染土壤来说联合修复技术的发展是土壤修复富有潜力的发展方向;应当尽可能地确定铅污染土壤修复机制,实现定向修复;同时应加强多功能复合材料的研发。      

The effects of age, smoking, and alcohol on routine laboratory tests

The effects of age, smoking, and alcohol intake on the results of some routine hematology and clinical chemistry tests have been determined for a group of 1,826 healthy male workers. Increasing age was significantly associated with higher hemoglobin, hematocrit, SGOT, BUN, and creatinine levels and with lower total protein concentration, but there was no significant association with leukocyte count, total bilirubin, or alkaline phosphatase. Smoking was significantly associated with higher hemoglobin, hematocrit, leukocyte count, and alkaline phosphatase, and with lower total bilirubin, SGOT, total protein, and BUN, but there was no significant association with creatinine levels. Alcohol consumption was significantly associated with higher hematocrit, bilirubin, and SGOT and with lower BUN and creatinine, but there was no significant association with hemoglobin, leukocyte count, alkaline phosphatase, or total protein. The possible reasons for these effects, and their implications, are discussed.     

Sintered antifriction materials

Some classes of sintered antifriction materials that form the basis for the development of new materials are discussed. Metal-and nonmetal-based materials with high wear resistance, low friction coefficient, and maximum lifetime are described. They differ in composition, structure (microheterogeneous, macroheterogeneous, layered, fibrous), carrying capacity, and potential for operation under various loads, at sliding rates, and in various conditions (high and low temperatures, corrosive and aggressive media, i.e., in water, acids, alkalis, melted metals, burning-hot gases, with and without lubrication, under high vacuum), in different friction modes (light, medium, heavy, and extremely heavy). The above materials are intended for application in the aviation, motorcar, chemical, oil, metallurgical, transportation, nuclear, textile, and food industries, in cryogenic, rocket, missile, and turbine engineering. Sintered antifriction materials are developed at the Frantsevich Institute for Problems of Materials Science, in particular, under the guidance of I. M. Fedorchenko, a famous materials scientist and academician.     

Concurrent and longitudinal effects of ethnic identity and experiences of discrimination on psychosocial adjustment of Navajo adolescents.

In this study, we examined concurrent and longitudinal relations among Navajo adolescents' ethnic identity, experiences of discrimination, and psychosocial outcomes (i.e., self-esteem, substance use, and social functioning). At Time 1, 137 Navajo adolescents (67 male, 70 female), primarily in Grades 9 and 10, completed a written survey assessing ethnic identity, discrimination experiences, and a range of internalizing and externalizing behaviors. Two years later, 92 participants completed the same survey again. Ethnic and cultural identification was assessed via the Multiethnic Ethnic Identity Measure (MEIM; Phinney, 1992) and the Orthogonal Cultural Identification Scale (OCIS; Oetting & Beauvais, 1990). At Time 1, MEIM Affirmation and Belonging, MEIM Exploration, and OCIS White American identification all demonstrated strong, positive associations with adaptive functioning for male and female adolescents, whereas discrimination experiences were linked to lower self-esteem and social functioning for male adolescents. By Time 2, fewer significant concurrent associations between ethnic identity and psychosocial functioning scores remained, and discrimination experiences emerged as the most consistent correlate of poorer psychosocial functioning for male adolescents. Controlling for Time 1 psychosocial functioning, relatively few direct effects of ethnic and cultural identification variables predicted psychosocial functioning longitudinally, but discrimination experiences demonstrated strong and consistent longitudinal links with boys' substance use. Finally, interaction effects assessing the moderating influence of ethnic and cultural identification on negative links between discrimination and psychosocial functioning suggested that embeddedness in and connection to Navajo culture and, in some cases, connection to White American culture, served as a buffer to the negative effects of discrimination experiences. (PsycINFO Database Record (c) 2011 APA, all rights reserved)