火电厂锅炉受热面爆漏原因分析及防措

锅炉受热面爆漏的发生,一直影响着火力发电厂的正常运行,造成巨大的经济损失,分析了水冷壁、过热器、再热器和省煤器爆漏原因,并对常见的爆管问题提出了相应的防范措施。

骨科患者医院感染调查分析及预防措施

目的探讨骨科患者医院感染的特点和预防控制措施。方法回顾性调查分析2002年7月～2007年6月骨科患者的医院感染率情况。结果我院骨科患者医院感染以手术切口感染、泌尿道感染和呼吸道感染最为常见，而且呼吸道感染与使用呼吸机、气管切开有相关性。引起医院感染最常见的病原菌为大肠埃希菌、铜绿假单胞菌、不动杆菌、克雷伯菌属、金黄色葡萄球菌、表皮葡萄球菌、肠球菌及白色念珠菌等。结论严格无菌操技术，规范侵入性操作，合理使用抗菌药物，提高机体的抵抗力，是骨科医院感染的预防控制措。

锅炉机组四管泄漏原因分析及防治措施

火力发电厂,锅炉"四管"的安全稳定,与发电机组的安全稳定经济运行是密不可分的,根据电厂省煤器、水冷壁、过热器、再热器的泄露事故,从泄露产生类型进行简要分析,并提出可行的预防措施,从而有利于机组安全运行。

煤矿皮带机跑偏原因及防跑偏措施

随着我国国民经济的不断发展,我国各个领域对煤矿需求量只增不减,所以相关企业对运输煤矿的机械就有了更多的要求。运输煤矿最为常见的机械设备就是皮带运输机,然而皮带机在运输煤矿的过程中经常出现跑偏的现象,这种现象极大影响了煤矿的整个运输流程。本文通过对煤矿皮带机的运输状况进行了简单概述,进而全面分析了煤矿皮带机跑偏的原因,有针对性地提出了几点防跑偏措施,旨在为相关工作人员提供有效的指导帮助。

发动机装配过程工艺防错技术探索

发动机是汽车的核心部件,是汽车制造商和车主最关心的问题,其运行情况直接关系到整车的质量。目前存在的主要问题是多个品种的动机混线装配,就会存在质量问题,经常出现装错、漏装等问题,遭到客户的投诉,给公司带来不利影响,还会给企业造成一定的经济防错技术损失。为了解决这些问题,提高产品质量,就需要针对复杂操作问题采取防错技术,以降低劳动强度,减轻劳动者的压力。本论文针对发动机装配过程工艺防措技术展开研究。

KYN18一12高压开关柜事故隐患分析及防范对策

本文主要对KYN18—12高压开关柜的各种潜在危险进行剖析,根据隐患的级别、伤害程度提出相应对策,致力于维护电网系统的正常运行和降低人员伤亡率。

Survey of damaging pests and preliminary assessment of forest health risks to the long term success of Pinus radiata introduction in Sichuan, southwest China

Pinus radiata was introduced to the summer rainfall environments of Sichuan Province, China in the 1990s as a part of an afforestation pmgram for soil and water conservation in the arid and semi-arid river valley area of Aba Prefecture. Within this region a total area of 26 000 ha have been identified through climate matching as suitable and a further 63 000 ha potentially suitable for environmental plantings of P. radiata. The plantations are being established in widely separated small patches on steep and degraded slopes along the dry river valley The newly introduced P. radiata are exposed to two kinds of forest health risks： they may be attacked by （a） indigenous pathogens and pests against which they may not possess any resistance or （b） by inadvertently introduced foreign pests or pathogens. This paper presents a survey of the potential damaging pests and a preliminary assessment of forest health risks facing the P. radiata plantations over a much longer timeframe than the initial phase of introduction and early plantation establishment. An empirical appmach was adopted to evaluate forest health risks by a combination of literature review, examination of historical records of pest and disease outbreaks in the surrounding conifemus forests, field surveys and inspections, specimen collection and identification, and most importantly, expert analysis of the likelihood of attack by specific pests and pathogens and the subsequent impact of such attacks. The assessment identified some specific forest health risks to the long-term success of P. radiata introduction in this area. These risks are closely associated with the indigenous pests and pathogens of the two native pine species, P. tabulaeformis and P. armondii since these pests and pathogens are considered more likely to establish on P. radiata over time. Exotic pests and pathogens are of a quarantine concern at present. Based on the results of assessment, recommendations are pmvided to improve forest vigour and to reduce the forest health risks posed by indigenous as well as exotic pests and pathogens to the introduced P. radiata. Ways to increase the ability to manage the forest health risks once a particular pest infestation and disease eventuates are also recommended. Although detrimental to the survival and growth of the introduced P. radiata, the impact of identified forest health risks are not considered to be fatal to the long term success ofP. radiata in this area.

Preservation of Parotid Masseter Fascia in Preventing Frey's Syndrome

Objective: To compare the functional outcomes of patients who had parotid masseter fascia reserved and unreserved flap elevating scheme in parotidectomy, especially the morbidity of Frey's syndrome. Methods: Twenty-three patients (group A) had parotid masseter fascia reserved in the parotidectomy, 32 patients (group B) had parotid masseter fascia unreserved in the operation. Compare the morbidity of gustatory sweating syndrome of the two groups. Results: Follow-up after 6 months to 2.5 years, gustatory sweating syndrome occurred in 4 patients of group A (17%), 17 patients in group B (57%). Conclusion: Reservation technic of the parotid masseter fascial in parotidectomy could prevent regeneration of parasympathetic nerve and thus prevent Frey's syndrome post-operation.

Comparison of the Evolution of Genetically Modified Food Safety Policies between the United States and the European Union

With the research on and development of Genetically Modified Food （GMF）, people＇s attitude toward GMF may fall into two divergent categories, typical- ly represented by the United States（US） and the European Union（EU）, respectively. The former follows a ＂sound science principle＂ and firmly objects to the precautionary principle, namely a permissive policy of positive support of and voluntary labelling on GMF; while the latter adopts a cautiously precautionary principle, requiring mandatory labelling and traceability. From the standpoint of regulatory principles, together with corresponding supervisory measures and relevant provisions, this paper compared the execution of directives and provisions on GMF from the initial policies enacted by the US and EU to current situation combined with the track and analysis of latest polic ies issued.

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes,analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation,and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system,the results indicate that the effects of noise in absorption region can be ignored;that with the increase of DC injecting current,the noise effects enhance power jitter,and nevertheless,the period jitter is decreased;and that with external sinusoidal current modulating the self-pulsation laser diode,the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.

Studies on the Relationship between Occurrence Degree of Cotton Bollworm and Rainfall

[ Objective ] The aim of the study is to investigate the factors causing the outbreak of cotton bollworm and to provide effective measures for controlling cotton bollworm. [ Method] Based on the analysis of the data about insect and weather situation in Luyi County in 32 years, the meteorological, prediction model was established for monitoring the quarterly or monthly occurrence trend of cotton bollworm. [Result] The cotton boillworm occurred slightly in the years with rainfalls of 3 months over 500 nm and severely in the years with rainfalls of 3 months： less than 400 rim. The results of correlation analysis show that annual occurrence degrees of cotton bollworm and occurrence degrees of 4^th generation of cotton bollworm are extremely negatively correlated with rainfall during June - August; the occurrence degrees of 3^rd and 4^th generations of cotton bollworm are also extremely negatively correlated with rainfall in July. [ Conclusion] The occurrence of cotton bollworm in field is heavily influenced by rainfall in at its occurrence stage; moreover, the rainfall during June - August is the decisive factors influencing the occurrence of cotton bollworm.

Wheat stripe rust resistance gene Yr24/Yr26：A retrospective review

The objective of this review is to describe events in China and elsewhere that are related to the discovery, genetic identification, use, and ultimate break-down of a single wheat gene for resistance to stripe rust, namely Yr24/Yr26. In our retrospective analysis there was an early assumption of at least three genes at or near the locus, which caused an erroneous presumption of genetic diversity for resistance. It is an example of another boom and bust cycle in plant breeding with races virulent to Yr26(V26 races) now being the majority race group in the Chinese Pst population. We have attempted to present our story in a historical and personal context demonstrating research inputs from different national and international groups, as well as some significant contemporary side issues. It covers the period from the late 1980 s to 2017, during which significant rapid advances in the molecular biology of host: pathogen genetics occurred. We attempt to describe both successes and drawbacks in our work.

Peripherally inserted central catheters in critically ill patients-complications and its prevention:A review

Peripherally inserted central catheter(PICC)is extensively used in critical care settings,because it plays a vital role in providing safe central venous entry.However,PICC is associated with several complications,which should be detected to shorten the duration of patients'improvement,reduce health care cost,and lessen the incidence of various PICC-related complications.Therefore,this study aimed to outline current literature on PICC procedures,potential complications,and measures for prevention.Understanding evidence-based guidelines regarding insertion technique,early detection of complications,and care bundle of PICC is significant in complication prevention.Implementation of education,training,and appropriate multidisciplinary approaches on PICC care among nurses and caregivers is the key to preventing complications.Thus,the strict care of indwelling PICC lines,the targeted and reasonable PICCassociated complication prevention,and nursing care have a major clinical significance in reducing the occurrence of potential PICC complications.

Assessment of Waterlogging Risk in Lixiahe Region of Jiangsu Province Based on AVHRR and MODIS Image

Four images of 1991 AVHRR, 2003 and 2007 MODIS were used to extract waterlogging inundated water of three years, and three inundated water maps were overlaid to estimate waterlogging affected frequency. Based on wa-terlogging affected frequency, waterlogging hazard of pixel scale was assessed. According to the weighed score of area percentage of different waterlogging affected frequency in 13 counties/cities of Lixiahe region, waterlogging hazard rank of every county/city was assessed. Waterlogging affected frequency map and 1km×1km grid landuse map were used to assess waterlogging risk of pixel scale; and then waterlogging risk rank of every county/city was assessed by the similar method by which waterlogging hazard rank of every county/city was assessed. High risk region is located mainly in core zone of Lixiahe hinterland, medium risk region is adjacent to high risk region, and low risk region is located in the most outlying area of risk zone and mainly in south to middle part of Lixiahe region. Xinghua and Gaoyou belong to high risk city, Jiangyan belongs to medium risk city, and the other counties/cities have low or lower waterlogging risk. The method of assessing waterlogging risk in this paper is simple and applicable. This paper can provide guidance for the waterlogging risk analysis in broader area of Huaihe River Basin.

Recent advances in the management of radiation colitis

Radiation colitis, an insidious, progressive disease of increasing frequency, develops 6 mo to 5 years after regional radiotherapy for malignancy, owing to the deleterious effects of the latter on the colon and the small intestine. When dealing with radiation colitis and its complications, the most conservative modality should be employed because the areas of intestinal injury do not tend to heal. Acute radiation colitis is mostly self-limited, and usually, only supportive management is required. Chronic radiation colitis, a poorly predictable progressive disease, is considered as a precancerous lesion; radiation-associated malignancy has a tendency to be diagnosed at an advanced stage and to bear a dismal prognosis. Therefore, management of chronic radiation colitis remains a major challenge owing to the progressive evolution of the disease, including development of fibrosis, endarteritis, edema, fragility, perforation, partial obstruction, and cancer. Patients are commonly managed conservatively. Surgical intervention is difficult to perform because of the extension of fibrosis and alterations in the gut and mesentery, and should be reserved for intestinal obstruction, perforation, fistulas, and severe bleeding. Owing to the difficulty in managing the complications of acute and chronic radiation colitis, particular attention should be focused onto the prevention strategies. Uncovering the fibrosis mechanisms and the molecular events underlying radiation bowel disease could lead to the introduction of new therapeutic and/or preventive approaches. A variety of novel, mostly experimental, agents have been used mainly as a prophylaxis, and improvements have been made in radiotherapy delivery, including techniques toreduce the amount of exposed intestine in the radiation field, as a critical strategy for prevention.

A study of pulmonary embolism after abdominal surgery in patients undergoing prophylaxis

AIM： To determine risk factors for pulmonary embolism and estimate effects and benefits of prophylaxis. METHODS： We included 78 patients who died subsequently to a pulmonary embolism after major abdominal surgery from 1985 to 2003. A first, retrospective analysis involved 41 patients who underwent elective surgery between 1985 and 1990 without receiving any prophylaxis. In the prospectively evaluated subgroup, 37 patients undergoing major surgery between 1991 and 2003 were enrolled： all of them had received a prophylaxis consisting in lowmolecular weight heparin, given subcutaneously at a dose of 2850 IU AXa/0.3 mL （body weight 〈 50 kg） or 5700 IU AXa/0.6 mL （body weight ≥ 50 kg）. RESULTS： A higher incidence of thromboembolism （43.9% and 46.34% in the two groups, respectively） was found in older patients （〉 60 years）. The incidence of pulmonary embolism after major abdominal surgery in patients who had received the prophylaxis was significantly lower compared to the subjects with the same condition who had not received any prophylaxis （P 〈 0.001, OR = 2.825; 95% CI, 1.811-4.408）. Furthermore, the incidence of pulmonary embolism after colorectal cancer surgery was significantly higher compared to incidence of pulmonary embolism after other abdominal surgical procedures. Finally, the incidence of pulmonary embolism after colorectal cancer surgery among the patients who had received the prophylaxis （11/4316, 0.26%） was significantly lower compared to subjects undergoing a surgical procedure for the same indication but without prophylaxis （10/1562, 0.64%） （P 〈 0.05, OR = 2.522; 95% Ct, 1.069-5.949）. CONCLUSION： Prophylaxis with low molecular weight heparin is highly recommended during the preoperative period in patients with diagnosis of colorectal cancer due to high risk of pulmonary embolism after elective surgery.

A shield against a monster:Hepatitis C in hemodialysis patients

Hepatitis C virus(HCV)infection is highly prevalent among patients on hemodialysis(HD).The prevalence of HCV infection in HD patients varies markedly from country to country.Some factors are especially related to these high prevalence rates,such as blood transfusions and length of dialysis time. Nosocomial routes of transmission including the use of contaminated equipment and patient-to-patient exposure is considered more important.Several prophylactic measures have been suggested to avoid infection by HCV in the HD environment.

Gastroenterology in developing countries:Issues and advances

Developing countries shoulder a considerable burden of gastroenterological disease. Infectious diseases in particular cause enormous morbidity and mortality. Diseases which afflict both western and developing countries are often seen in more florid forms in poorer countries. Innovative techniques continuously improve and update gastroenterological practice. However, advances in diagnosis and treatment which are commonplace in the West, have yet to reach many developing countries. Clinical guidelines, based on these advances and collated in resource-rich environments, lose their relevance outside these settings. In this two-part review, we first highlight the global burden of gastroenterological disease in three major areas： diarrhoeal diseases, hepatitis B, and Helicobacter pylori. Recent progress in their management is explored, with consideration of future solutions. The second part of the review focuses on the delivery of clinical services in developing countries. Inadequate numbers of healthcare workers hamper efforts to combat gastroenterological disease. Reasons for this shortage are examined, along with possibilities for increased specialist training. Endoscopy services, the mainstay of gastroenterology in the West, are in their infancy in many developing countries. The challenges faced by those se^ing up a service are illustrated by the example of a Nigerian endoscopy unit. Finally, we highlight the limited scope of many clinical guidelines produced in western countries. Guidelines which take account of resource limitations in the form of ＂cascades＂ are advocated in order to make these guidelines truly global. Recognition of the different working conditions facing practitioners worldwide is an important step towards narrowing the gap between gastroenterology in rich and poor countries.

Positive Selection Analysis of VP1 Genes of Worldwide Human Enterovirus 71 Viruses

Human enterovirus 71 viruses have been long circulating throughout the world. In this study, we performed a positive selection analysis of the VP1 genes of capsid proteins from Enterovirus 71 viruses. Our results showed that although most sites were under negative or neutral evolution, four positions of the VP1 genes were under positive selection pressure. This might account for the spread and frequent outbreaks of the viruses and the enhanced neurovirulence. In particular, position 98 might be involved in neutralizing antibodies, modulating the virus-receptor interaction and enhancing the virulence of the viruses. Moreover, both positions 145 and 241 might correlate to determine the receptor specificity. However, these positions did not display much difference in amino acid polymorphism. In addition, no position in the VP1 genes of viruses isolated from China was under positive selection.

Human herpesvirus 6 infections after liver transplantation

Human herpesvirus 6(HHV-6) infections occur in > 95% of humans.Primary infection,which occurs in early childhood as an asymptomatic illness or manifested clinically as roseola infantum,leads to a state of subclinical viral persistence and latency.Reactivation of latent HHV-6 is common after liver transplantation,possibly induced and facilitated by allograft rejection and immunosuppressive therapy.Since the vast majority of humans harbor the virus in a latent state,HHV-6 infections after liver transplantation are believed to be mostly due to endogenous reactivation or superinfection(reactivation in the transplanted organ).In a minority of cases,however,primary HHV-6 infection may occur when an HHV-6 negative individual receives a liver allograft from an HHV-6 positive donor.The vast majority of documented HHV-6 infections after liver transplantation are asymptomatic.In a minority of cases,HHV-6 has been implicated as a cause of febrile illness with rash and myelosuppression,hepatitis,pneumonitis,and encephalitis after liver transplantation.In addition,HHV-6 has been associated with a variety of indirect effects such as allograft rejection,and increased predisposition and severity of other infections including cytomegalovirus(CMV),hepatitis C virus,and opportunistic fungi.Because of the uncommon nature of the clinical illnesses directly attributed to HHV-6,there is currently no recommended HHV-6-specific approach to prevention.However,ganciclovir and valganciclovir,which are primarily intended for the prevention of CMV disease,are also active against HHV-6 and may prevent its reactivation after transplantation.The treatment of established HHV-6 disease is usually with intravenous ganciclovir,cidofovir,or foscarnet,complemented by reduction in the degree of immunosuppression.This article reviews the current advances in the pathogenesis,clinical diagnosis,and therapeutic modalities against HHV6 in the setting of liver transplantation.