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。     

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。     

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。     

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。     

Lipid peroxidation and antioxidant status in the liver, erythrocytes, and serum of rats after methanol intoxication

Lipid peroxidation products measured as a malondialdehyde and activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-R), and concentrations of ascorbic acid, alpha-tocopherol, and glutathione (GSH) were measured in the liver, erythrocytes, and serum of rats 6, 14, and 24 h and 2, 5, and 7 d after treatment with 3 g methanol/kg. GSH-Px and GSSG-R activities, GSH level, and ascorbate concentration in the liver, erythrocytes, and blood serum were significantly decreased. In addition, SOD and alpha-tocopherol in erythrocytes were diminished, while malondialdehyde (MDA) in liver, erythrocytes, and serum were elevated. Further, erythrocyte counts, hemoglobin levels, hematocrit, and mean corpuscular volume (MCV) were reduced. These results indicate that methanol intoxication in rats leads to an increase in the lipid peroxidation and impairment in the antioxidant mechanisms in liver, erythrocytes, and blood serum.     

Comparison of six-month outcome of coronary artery stenting in patients <65, 65-75, and >75 years of age

We studied 1,238 patients receiving 1,880 coronary stents. In-hospital outcomes were divided by age into <65 years (n = 747, group 1), 65 to 75 years (n = 326, group 2), and >75 years (n = 165, group 3). Procedural success was 97.2%, 95.1%, and 98.8% in groups 1, 2, and 3, respectively (p = NS). There was 1 death (group 1). Myocardial infarction occurred in 1.2%, 2.8%, and 1.8%, bypass surgery occurred in 0.9%, 1.8%, and 1.2%, and repeat balloon angioplasty in 0.3%, 0.6%, and 0% of patients in groups 1, 2, and 3, respectively (p = NS for all comparisons). Vascular complications occurred in 2.8%, 4.9%, and 6.1% in groups 1, 2, and 3, respectively (p <0.05). Six-month follow-up of patients was divided by age: <65 years (n = 564, group 1); 65 to 75 years (n = 221, group 2); and >75 years (n = 122, group 3). Event-free survival was 94.5%, 90.5%, and 89.3% for groups 1, 2, and 3, respectively (p = NS). Death occurred in 0.4%, 0.5%, and 1.6%; myocardial infarction occurred in 1.2%, 2.3%, and 1.6%, and target vessel revascularization in 4.3%, 8.6%, and 7.4% for groups 1, 2, and 3, respectively (p = NS for all comparisons). Thus, coronary stenting produced favorable in-hospital and 6-month outcomes in all 3 age groups. Age itself should not preclude patients from undergoing coronary stenting.     

Building a framework for two internal organizational approaches to resolving and preventing workplace bullying: Alternative dispute resolution and training.

Workplace bullying is behavior that threatens, intimidates, humiliates, or isolates people at work, or undermines their reputation or job performance. Moving beyond research, academics and employment practitioners are beginning to address the need to design and implement organizational antibullying policies, training, conflict management programs and systems, and possibly, antibullying public policy and legislation. Consultants will play a key role in helping organizations develop and implement internal organizational programs. In this paper the authors describe alternative dispute resolution systems and workplace training. Key objectives include arriving at a clear definition of workplace bullying, fostering individual, organizational, and societal awareness of the prevalence and consequences of workplace bullying; and providing specific guidance and mechanisms for individuals, managers, human resource departments, corporate leadership, union representatives, attorneys, physicians, counselors, psychologists, and psychiatrists, for preventing and handling bullying incidents. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Algorithm for Purkinje images I and IV and limbus centre localization

Significant advances have been made in the study of the small bowel. Part I of this two-part review of the small bowel examines carbohydrates, including brush border membrane hydrolysis and sugar transport; amino acids, dipeptides, proteins and food allergy, with a focus on glutamine, peptides and macromolecules, and nucleosides, nucleotides and polyamines; salt and water absorption, and diarrhea, including antidiarrheal therapy and oral rehydration treatment; lipids (digestion and absorption, fatty acid binding proteins, intracellular metabolism, lipoproteins and bile acids); and metals (eg, iron) and vitamins.     

Distribution of the protein kinase C substrates MARCKS and MRP in the postnatal developing rat brain

The myristoylated alanine-rich C kinase substrate (MARCKS) and MARCKS-related protein (MRP) are both membrane-associated phosphoproteins that interact with calmodulin and filamentous actin in a protein kinase C phosphorylation-dependent manner. In the present study, we examined MARCKS and MRP gene expression in the postnatal (P) rat brain (1, 7, 14, 21, and 90 days after birth) by using quantitative in situ hybridization. At P1, MRP expression was high in neocortex, striatum, thalamus, cerebellar cortex, and hippocampus (CA1-CA3, hilus, and granule cell layer) but low in brainstem and, between P7 and P14, exhibited a dramatic decline in each of these regions except hippocampal CA1 and granule cell layers. Between P14 and P21, MRP expression increased in white matter regions including the corpus callosum, fimbria/fornix, and cerebellar deep white matter. At P90 (adult), MRP remained strongly expressed in the olfactory bulb, medial habenula, hippocampal CA1, and the inner two-thirds of granule cell layer, temporal, and entorhinal cortices, the corpus callosum and fimbria/fornix, and cerebellar white matter. At P1, MARCKS was strongly expressed in the majority of brain regions except the brainstem, which subsequently declined gradually to approximate adult levels by P14. Between P14 and P21, MARCKS expression declined gradually in the hilus, remained elevated in hippocampal CA1, CA3, and granule cell layers, and increased dramatically in the corpus callosum and fimbria/fornix. At P90, MARCKS expression declined in hippocampal CA3 and hilus and remained strongly expressed in hippocampal CA1 and granule cell layers, regions of the olfactory bulb, the medial habenula, temporal cortex, and cerebellar granule and Purkinje cells. Expression of both MARCKS and MRP in regions undergoing neuronal proliferation, migration, and neurite outgrowth suggest a common role in these developmental events, whereas differences in expression during development and in the adult brain provide evidence of differential regulation.     

The utility of high-resolution magnetic resonance imaging in the evaluation of the triangular fibrocartilage complex of the wrist

This work offers an anthropological analysis of intra-household processes underlying gender- and age-specific differences in individual nutritional and health care allocations and outcomes in particular cultures. Based on recent ethnographic studies in India, Nepal, Madagascar, Mexico, and Peru, correspondences are analyzed between local cultural ("emic") and scientist-policy maker practitioner ("etic") understandings of nutrition, health, and human development, and the relative "values" of females, males, and children of different ages. The data and analyses clarify specific epidemiological and demographic findings on age and gender bias in nutrition and health and highlight the multiple cultural, economic, and biological factors that contribute to gender- or age-based discrimination or neglect. Recent advances in nutrition policy have argued for a broader concept of nutritional security, one that incorporates both food quantity and quality, and of nutrition as "food, health and care" (International Conference on Nutrition, World Declaration and Plan of Action for Nutrition, FAO/WHO, Rome, 1992). These ethnographic findings; lend strong support for such broader nutrition concepts and associated nutrition policies. The studies also suggest ways in which anthropological questions, methods, and data and community-based research can help predict or identify the nutritionally vulnerable within households and help other social and medical scientists design more effective interventions.     

Cancer and other causes of death among male and female farmers from twenty-three states

Occupation and industry codes on death certificates from 23 states for 1984-1988 were used to evaluate mortality risks among white and nonwhite, male and female farmers. Proportionate mortality and proportionate cancer mortality ratios were calculated using deaths among nonfarmers from the same states to generate expected numbers. Among farmers there were 119,648 deaths among white men, 2,400 among white women, 11,446 among nonwhite men, and 2,066 among nonwhite women. Deficits occurred in all race-sex groups for infective and parasitic diseases, all cancer combined, lung cancer, liver cancer, diseases of the nervous system, multiple sclerosis, hypertension, and emphysema. As reported in other studies, white male farmers had excesses of cancer of the lymphatic and hematopoietic system, lip, eye, brain, and prostate. Excesses of cancers of the pancreas, kidney, bone, and thyroid were new findings. Regional patterns were evident, particularly among white men. Significant excesses for accidents, vascular lesions of the central nervous system (CNS), and cancers of the prostate tended to occur in most geographic regions, while excesses for mechanical suffocation, non-Hodgkin's lymphoma, and cancers of the lip, brain, and the lymphatic and hematopoietic system were limited to the Central states. Increases among nonwhite men were similar to those in white men for some causes of death (vascular lesions of the CNS and cancers of the pancreas and prostate), but were absent for others (lymphatic and hematopoietic system, lip, eye, kidney, and brain). Women (white and nonwhite) had excesses for vascular lesions of the CNS, disease of the genitourinary system (white women only), and cancers of the stomach and cervix (nonwhite women only). Cancer of the buccal cavity and pharynx was slightly elevated among women, and white women had nonsignificant excesses of multiple myeloma and leukemia. Excesses for leukemia and non-Hodgkin's lymphoma occurred among white men and women, but not among nonwhites. Excesses for several types of accidental deaths were seen among all race-sex groups.     

Transport of dopamine at the blood-brain barrier of the guinea pig: inhibition by psychotropic drugs and nicotine

Diagnostic procedures for detection of infectious laryngotracheitis virus in tracheas of experimentally infected chickens, including the indirect fluorescent antibody test (IFAT), immunoperoxidase (IP), virus isolation (VI), histopathology, polymerase chain reaction (PCR), and DNA hybridization, were performed and compared. Using VI as a reference, we calculated the sensitivity and specificity of the tests. The sensitivities of IP, IFAT, histopathology, PCR, and hybridization were 100%, 93%, 7%, 27%, and 0%, respectively, and the specificities of IP, IFAT, histopathology, PCR, and hybridization were 93%, 93%, 100%, 100%, and 100%, respectively. Histopathology, PCR, and hybridization were more specific but lacked sensitivity compared to IP and IFAT. IP and IFAT were equally specific, but IP was more sensitive than IFAT. Based on these results, IP performed better than any other test.     

脉动热管的理论研究与应用新进展

作为一种工作机理独特的新型传热装置,脉动热管具有极高的传热效率、较高的抗烧干能力、良好的环境适应性,且结构简单、可变,成本较低,具有很高的实际应用价值,是目前传热技术领域的研究热点.本文在对脉动热管的优点、结构形式和工作原理进行总体介绍的基础上,首先从理论建模研究入手归纳了目前研究中通常采用的直管、单弯头管、部分单弯头管等结构模型和质量-弹簧-阻尼模型,质量、动量、能量方程模型以及其他数学模型,然后从实验可视化研究和计算可视化研究两方面综述了脉动热管的运行过程、工作机理以及近年来国内外在脉动热管方面的最新研究进展,从启动性能、传热性能和传热极限三方面系统介绍了管径、长度、截面形状、加热方式、充液率、倾斜角度、输入功率和工作流体种类等不同设计和使用参数对脉动热管性能的影响.进一步从设计与应用方面,对脉动热管在电子设备、太阳能集热、动力装置热管理和低温环境换热等方面的研究进行了综述,展示了脉动热管在实际应用中的效果和优势.最后对今后的研究方向与发展趋势进行了展望,指出可通过更详细的理论和仿真建模研究脉动热管的工作机理、工作性能、工作过程和优化设计方法.      

Distribution of plasma phosphatidylcholine molecular species in rabbits fed fish oil is modulated by dietary n-6 fatty acids

Natural occurrence of Fusarium mycotoxins (trichothecenes and fumonisins) and aflatoxin B1 (AFB1) were surveyed in 32 corn samples, harvested in 1993 and randomly sampled in 1994 in several districts of Hanoi, Vietnam. Corn samples were first milled into fine powder, extracted with methanol-water (3:1) and the crude extracts obtained from the same samples were used for the simultaneous analysis of the trichothecenes such as nivalenol (NIV), deoxynivalenol (DON), and T-2 toxin (T-2) by gas chromatography/mass spectrometry (GC/NS); fumonisins B1 (FB1), B2 (FB2), and B3 (FB3) by high-performance liquid chromatography (HPLC) with a flourescence detector; and AFB1 by and ELISA kit based on a monoclonal antibody. The data revealed that 14, 8, 4, 3, and 2 out of 15 corn kernel samples were positive for AFB1, FB1, FB2, FB3, and NIV with the average levels being 28, 1, 101, 276, 232, and 858 ppb, respectively, and neither DON nor T-2 were detected. As for the other 17 samples of corn powder, 13, 15, 12, 10, 4 and 2 were positive for AFB1, FB1, FB2, FB3, DON, and NIV with the average being 30, 780, 289, 176, 3, 170, and 1,365 ppb, respectively, and T-2 was not detected. Although their positive rates and levels fell in the ranges reported elsewhere, it was found for the first time that the Fusarium toxins (NIV, DON, and fumonisins) and an Aspergillus toxin (AFB1) were naturally co-contaminated in selected samples of corn produced in north Vietnam.