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1.
高压XLPE电缆的缓冲层是电缆的重要组成部分,对电缆的机械、热、电性能具有重要的影响。而电缆 在实际运行时,由于电缆的热机械运动会使得电缆金属护套脱离电缆绝缘外屏蔽,使电场分布发生改变。本文通 过分析高压XLPE电缆结构,研究了高压XLPE电缆金属护套与绝缘外屏蔽层放电现象的产生和发展。研究及仿 真结果表明:电缆内的电场分布受金属护套与绝缘屏蔽层之间放电间隙的绝缘状态影响,其放电过程发生在电缆 缆芯靠近波纹铝护套直至完全贴合的瞬间,且缓冲层的性能变化会加剧金属护套与绝缘屏蔽层之间放电。  相似文献   

2.
高压XLPE电缆的缓冲层是电缆的重要组成部分,对电缆的机械、热、电性能具有重要的影响。而电缆在实际运行时,由于电缆的热机械运动会使得电缆金属护套脱离电缆绝缘外屏蔽,使电场分布发生改变。本文根据110kV XLPE电缆结构及实际尺寸,计算了110kV XLPE发生放电现象时对电缆金属护套与绝缘外屏蔽脱离距离的要求。计算结果表明:电缆内放电距离受金属护套与绝缘屏蔽层之间放电间隙的绝缘状态影响,同时放电间隙的减小会加剧金属护套与绝缘屏蔽层之间放电,且电缆截面越大越容易发生放电现象。  相似文献   

3.
通过对齐齐哈尔市地区中高压电缆外护套故障的调查和分析,说明高压和超高压XLPE绝缘电缆外护套应有的绝缘性能和防水性能,外护套故障存在的严重性,提出的对策是对外护套及时、有效修补。  相似文献   

4.
本文通过建立电缆金属护套与绝缘外屏蔽层之间的放电模型,分析了放电的产生与发展过程,仿真了电缆偏心和缓冲层介电常数变化时的电场分布,并对金属护套与绝缘外屏蔽层之间的电场分布规律进行了总结。  相似文献   

5.
本文分析了66kV XLPE绝缘电力电缆金属护套接地电流产生的原理,结合长春地区运行中的部分66kV XLPE绝缘电力电缆金属护套接地电流的普查情况,分析了电缆金属护套接地电流异常的原因,提出解决的措施。  相似文献   

6.
高压电缆系统发生单相短路时在金属护套内会产生过电压,该过电压常常高于电缆外护层的绝缘水平,同时也高于保护器的工频耐压能力。布置回流线的目的是降低该过电压,最大限度避免外护层绝缘和保护器击穿损坏。  相似文献   

7.
单芯钢丝铠装电缆由于铠装层的损耗,不仅影响电缆本身的载流量,而且当接地方式不当时,极易造成接地故障,影响线路正常运行。本文通过对钢丝铠装层的感应电流,感应电压的测量,分析了其与线芯电流的关系。揭示了长时间运行后,接地点的高温破坏电缆内护套,导致钢丝铠装层与铜屏蔽层连通,从而形成回路,进一步破坏绝缘与护套的事实,从而给出了单芯钢丝铠装电缆正确的敷设及接地方式。  相似文献   

8.
在高压皱纹铝套交联电缆非金属护套生产管理中,精确把控非金属外护套的用量,是长期以来的难点。本文对高压交联电缆非金属外护套的用量常用计算方法进行了研究;根据皱纹铝套高压交联电缆非金属护套结构特点,提出了一种皱纹铝套高压交联电缆非金属护套新的计算方法,基于这种计算方法与实际生产用量对比分析,确定皱纹铝套高压交联电缆非金属护套用量计算的新方法,为今后精确用量指明方向。  相似文献   

9.
高压单芯电缆金属护套不同的接地方式会对高压单芯电缆产生不同的运行效果,不正确的接地方式在遇到线路短路故障、雷击冲击及操作过电压时金属护套中会形成很高的感应电压,直接威胁人身和电缆的运行安全,同时,不正确的接地方式会在电缆金属护套中形成环流,电缆金属护套长期处在环流中会直接影响到电缆的载流量造成损耗电源电能。  相似文献   

10.
为解决长兴岛的供电缺口问题,在长兴岛和崇明岛之间敷设了两回3×400mm2铜芯交联聚乙烯绝缘铅合金金属护套、钢丝铠装、聚丙烯纱护层、且线芯间的空隙中设24芯光纤的光缆的复合海底电缆。本文介绍了电缆的结构、选型标准、试验项目以及安装的概要。该电缆已于2005年4月投入运行。  相似文献   

11.
Objective: To evaluatel the value of D-dimers in patients with acute aortic dissection (AAD). Methods: This study consisted of 16 patients with AAD and 27 non-AAD patients. Serum D-dimets were measured by Sta-Liatest D-DI immunoturbidimetric assay. Results: D-dimer level was higher (P < 0.001) in patients with AAD(7.91 ± 5.52 μg/ml) than that in non- AAD group(1.57±1.24 μg/ml). D-dimer was positive (>0.4 μg/ml) in all patients with AAD and in 10 control group patients (37%). Among patients with acute AAD, D-dimers tended to be higher in Stanford A than in Stanford B (8.67 ± 4.31 μg/ml vs. 3.24±1.27 μg/ml, P <0.01). D-dimer values tended to be higher in more extended disease(3.84 ± 1.65 μg/ml, 8.57 ± 3.58 μg/ml and 11.87 ± 5.69 μg/ml in thoracic aorta, thoracic and abdominal aorta, thoracic and abdominal aorta and iliacal arteries, respectively, P < 0.05 for both 8.57 ± 3.58 and 11.87 ± 5.69 vs. 3.84 ± 1.65 ). Including the control group into the analysis, we found a sensitivity of 100%, a negative predictive value of 100%, and a specificity of 66% and a positive predictive value of 64% for D-dimer in diagnosis of AAD in our patients with suspected AAD. Conclusion: D-dimer was elevated in patients with AAD. A negative D-dimer test result could be useful in excluding AAD.  相似文献   

12.
Objective: To set up a simple and reliable rat model of combined liver-kidney transplantation. Methods: SD rats served as both donors and recipients. 4℃ sodium lactate Ringer's was infused from portal veins to donated livers,and from abdominal aorta to donated kidneys, respectively. Anastomosis of the portal vein and the inferior vena cava (IVC) inferior to the right kidney between the graft and the recipient was performed by a double cuff method, then the superior hepatic vena cava with suture. A patch of donated renal artery was anastomosed to the recipient abdominal aorta. The urethra and bile duct were reconstructed with a simple inside bracket. Results: Among 65 cases of combined liver-kidney transplantation, the success rate in the late 40 cases was 77.5%. The function of the grafted liver and kidney remained normal. Conclusion: This rat model of combined liver-kidney transplantation can be established in common laboratory conditions with high success rate and meet the needs of renal transplantation experiment.  相似文献   

13.
FOR anesthesiologis s ,treatingpostoperativepainhas alwaysbeen a problem.Althoughopioidshave been provedtobe effective,theirsideeffectscouldnotbeignored.With thedevelopmentofscienceand pharmacology,many drugs with aspectsof satisfactoryanalgesicefficacyand couldbe welltoleratedby patientshave been developed.And lornoxicamisone of them, which isa non-steroidalanti-inflammatorydrug (NSAID ), with analgesic, anti-infl-ammatory,andantipyreticproperties.Itseliminationhalf-time(3 to 5 hours) isle…  相似文献   

14.
目的:评价使用安心颗粒对急诊经皮冠状动脉介入术(PPCI)术后生活质量的影响.方法:将160例接受PPCI的急性ST段抬高型心肌梗死患者随机分为安心颗粒组(术前顿服安心颗粒8.8g,术后安心颗粒4.4 g/次,每日2次)和对照组(仅接受基础药物治疗).所有患者均服用阿司匹林、氯吡格雷和阿托伐他汀.分别在入院时、出院前1d、出院后180 d时,应用心肌梗死多维度量表(MIDAS)、中文版SF-36评价量表对患者生活质量评分.并观察术后30 d以内的出血并发症、血小板减少症发生情况.结果:入院时和出院前1d,两组患者的心肌梗死MIDAS、SF-36量表评分比较无差异(P>0.05);出院后180 d时,与对照组比较,安心颗粒组MIDAS、SF-36评分明显减低(P<0.05);组内与入院时比较,两组出院前1d、出院后180 d时,MIDAS、SF-36评分均降低(P<0.05).两组患者在随访期间均无大量出血、少量出血、重度和极重度血小板减少症发生,安心颗粒组有4例、对照组有7例发生不明显出血(P>0.05).两组发生轻度血小板减少症的患者数比较无差异(P>0.05).结论:PPCI使用安心颗粒,能改善急性ST段抬高型心肌梗死患者的生活质量,且不增加出血风险.  相似文献   

15.
Objective:To investigate the influences of urapidil and nicardipine on rabbit sinus function,atrio-ventricular node function and hemodynamics.Methods:Thirty-two Angora's rabbits were selected and randomly divided into four groups.U1 group:urapidil 0.25 mg/kg;U2 group:urapidil 0.5 mg/kg;N1 group:nicardipine 10 μg/kg;N2 group:nicardipine 20 μg/kg.All these medicine were administrated within 30 seconds.Measurements were taken before and after the administration of urapidil or nicardipine for the following data:mean blood pressure(MAP),heart rate(HR),sino-atrial conduction time(SACT),maximal sinoatrial recovery time(SNRTmax)corrected sinus node recovery time(CSNRT),index of sinus node recovery time(SNRTI),Wenckebach A-V conduction frequency (WB),and P-R interval.Results:Significant MAP and HR changes were identified in all of the four groups before and after administration of both urapidil and nicardipine.No significant changes could be found in the rest of the parameters.Intergroup analysis showed that SACT and CSNRT of N1 and N2 groups were shorter than those of the U2 group(P<0.01);the MAP decreased(P<0.01)and the HR increased drastically(P<0.01).Conclusions:Neither urapidil(0.25 mg/kg,0.5 mg/kg)nor nicardipine(10μg/kg,20μg/kg)has any significant influence on rabbit sinus function or rabbit atrio-ventricular node function.Nicardipine could be a better choice than urapidil for parafunctional sinus node patients.  相似文献   

16.
Objective:To investigate the gene expression of osteoprotegerin(OPG) and osteoclast differentiation factor(ODF) in the bone tissue of patients with hip fracture due to osteoporosis. Methods:OPGmRNA and ODFmRNA in the bone tissue in 50 cases of osteoporosis sufferers(over 50 years old) with hip fracture(Observer Group) and 30 cases of hip facture sufferers with no osteoporosis(Control group) were analyzed with the Semi-Quantitative RT-PCR method. Results:The mRNA expressed of ODF, OPG were both high in the patients with hip fracture. In the control group, the expression of OPG mRNA was observed, while the expression of ODF mRNA was very slight. Conclusion:Aged patients contained all signals including OPG, ODF that are essential for inducing osteoclastogenesis and promoting bone resorption.  相似文献   

17.
Objective:To investigate the clinical features, pathological characteristics and immunophenotype of solid-pseudopapillary tumor of the pancreas(SPTP). Methods:Nine surgically treated cases of SPTP were retrospectively reviewed. Hematoxylin and Eosin(HE) staining and immunohistochemical staining were used to analyze all cases, and the general clinical data was collected. Results:Six patients were asymptomatic except for a palpable mass. Two patients complained of vague-epigastric pain. One patient appeared jaundice. The tumor was encapsulated and solid tissues alternately with cystic tissues. Histologically, the histological structure of solid portion was pseudopapillary with a fibrovascular core. Tumor cells were uniform and medium-sized which were arranged in sheets ets or nests or pseudopapillary patterns. Immunohistochemical studies demonstrated that SPTP proved positive in vimentin(9/9 cases), AAT(9/9 cases), NSE(9/9 cases), ACT(7/9 cases), CK20(2/9 cases), CgA(1/9 cases), S-100(3/gcases), PR(4/gcases), Syn(3/9 cases) and CD56(5/9cases), negative in CEA and ER. Conclusion:SPTP is a tumor predominantly occurring in young women frequently without special symptoms. This tumor has various characteristical histological patterns with different immunophenotype.  相似文献   

18.
Objective: To observe the therapeutic effects in acupunture treatment of primary dysmenorrhea combined with spinal Tui Na, and study its mechanism. Methods: Thirty cases of the treatment group were treated by acupuncture combined with spinal Tui Na, and thirty cases in the control group were treated by routine acupuncture. Results: The total effective rate was 93.3% in the treatment group, and 73.3% in the control group, with a significant difference between the two groups (P<0.05). Conclusions: Acupuncture combined with spinal Tui Na has good prospects for treatment of primary dysmenorrhea.  相似文献   

19.
In treating chronic nephropathy,Luo Lingjie,a chief physician,pays attention to regulating the balance between yin and yang,treating infection if present,and removing pathogenic factors.He prescribes gentle drugs and uses carefully strongly warming-tonifying ones,emphasizes the importance of persuading the patient to persist in treatment with medication and nurse one's health for recuperation,and is good at combined use of TCM and western medicine therapy and brings the merits of various therapies into full play,with obvious theraoeutic effects.  相似文献   

20.
Dr.Zhang Ren,the chief physician,is the chairman of Shanghai Acupuncture and Moxibustion Association.Having been engaged in medicine for about 40 years,he is experienced in treating various intractable diseases.In his long years of clinical practice,he advocates taking the TCM differentiation as the basis to seek for the acupuncture method for treatment of modern intractable diseases.The author of this essay had the fortune to follow Dr.Zhang in study.The following is a summary of Dr.Zhang's experience in the acupuncture treatment for different intractable diseases with the same therapeutic principle.  相似文献   

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