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Nasogastric tube syndrome:A Meta-summary of case reports
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作者 Deven Juneja Prashant Nasa +1 位作者 Gunjan Chanchalani Ravi Jain 《World Journal of Clinical Cases》 SCIE 2024年第1期119-129,共11页
BACKGROUND Since its description in 1790 by Hunter,the nasogastric tube(NGT)is commonly used in any healthcare setting for alleviating gastrointestinal symptoms or enteral feeding.However,the risks associated with its... BACKGROUND Since its description in 1790 by Hunter,the nasogastric tube(NGT)is commonly used in any healthcare setting for alleviating gastrointestinal symptoms or enteral feeding.However,the risks associated with its placement are often underes-timated.Upper airway obstruction with a NGT is an uncommon but potentially life-threatening complication.NGT syndrome is characterized by the presence of an NGT,throat pain and vocal cord(VC)paralysis,usually bilateral.It is poten-tially life–threatening,and early diagnosis is the key to the prevention of fatal upper airway obstruction.However,fewer cases may have been reported than might have occurred,primarily due to the clinicians'unawareness.The lack of specific signs and symptoms and the inability to prove temporal relation with NGT insertion has made diagnosing the syndrome quite challenging.AIM To review and collate the data from the published case reports and case series to understand the possible risk factors,early warning signs and symptoms for timely detection to prevent the manifestation of the complete syndrome with life-threatening airway obstruction.METHODS We conducted a systematic search for this meta-summary from the database of PubMed,EMBASE,Reference Citation Analysis(https://www.referencecitation-analysis.com/)and Google scholar,from all the past studies till August 2023.The search terms included major MESH terms"Nasogastric tube","Intubation,Gastrointestinal","Vocal Cord Paralysis",and“Syndrome”.All the case reports and case series were evaluated,and the data were extracted for patient demographics,clinical symptomatology,diagnostic and therapeutic interventions,clinical course and outcomes.A datasheet for evaluation was further prepared.RESULTS Twenty-seven cases,from five case series and 13 case reports,of NGT syndrome were retrieved from our search.There was male predominance(17,62.96%),and age at presentation ranged from 28 to 86 years.Ten patients had diabetes mellitus(37.04%),and nine were hypertensive(33.33%).Only three(11.11%)patients were reported to be immunocompromised.The median time for developing symptoms after NGT insertion was 14.5 d(interquartile range 6.25-33.75 d).The most commonly reported reason for NGT insertion was acute stroke(10,37.01%)and the most commonly reported symptoms were stridor or wheezing 17(62.96%).In 77.78%of cases,bilateral VC were affected.The only treatment instituted in most patients(77.78%)was removing the NG tube.Most patients(62.96%)required tracheostomy for airway protection.But 8 of the 23 survivors recovered within five weeks and could be decannulated.Three patients were reported to have died.CONCLUSION NGT syndrome is an uncommon clinical complication of a very common clinical procedure.However,an under-reporting is possible because of misdiagnosis or lack of awareness among clinicians.Patients in early stages and with mild symptoms may be missed.Further,high variability in the presentation timing after NGT insertion makes diagnosis challenging.Early diagnosis and prompt removal of NGT may suffice in most patients,but a significant proportion of patients presenting with respiratory compromise may require tracheostomy for airway protection. 展开更多
关键词 Nasogastric tube Nasogastric tube syndrome Ryle’s tube sofferman syndrome Vocal cord paralysis
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Schlemm管外壁切除治疗开角型青光眼的临床观察 被引量:1
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作者 任桂芳 任桂杰 +1 位作者 张秀萍 邵铁军 《山东大学基础医学院学报》 2002年第6期369-370,共2页
目的 :观察Schlemm管外壁切除联合应用丝裂霉素C治疗开角型青光眼的临床疗效。方法 :对中晚期开角型青光眼 17例、18眼行Schlemm管外壁切除术 ,术中应用丝裂霉素C 0 .2mg/ml。结果 :16眼术后眼压控制在 1.36~ 2 .5 1kPa ,2眼术后眼压为... 目的 :观察Schlemm管外壁切除联合应用丝裂霉素C治疗开角型青光眼的临床疗效。方法 :对中晚期开角型青光眼 17例、18眼行Schlemm管外壁切除术 ,术中应用丝裂霉素C 0 .2mg/ml。结果 :16眼术后眼压控制在 1.36~ 2 .5 1kPa ,2眼术后眼压为 2 .98~ 3.2 4kPa ,点 0 .5 %噻吗心胺眼水后 ,眼压控制在正常范围。结论 :Schlemm管外壁切除加应用丝裂霉素C ,可有效地降低眼压 ,减少抗青光眼药物的应用 ,术后并发症少 。 展开更多
关键词 schlemm管外壁切除 治疗 开角型青光眼 临床观察
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原发性开角型青光Schlemm管和集液管的病理形态学研究
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作者 易敬林 傅甜 +1 位作者 谢程阳 钟文贤 《江西医药》 CAS 2008年第5期402-406,共5页
目的研究原发性开角型青光眼(primary open-angle glaucoma,POAG)中集液管和Schlemm管的组织病理学特征,以探讨影响房水外流的阻力因素。方法选取经临床确诊的POAG病人20例(30眼)和经筛选的正常尸眼30只,采用透射电镜技术对房角组织进... 目的研究原发性开角型青光眼(primary open-angle glaucoma,POAG)中集液管和Schlemm管的组织病理学特征,以探讨影响房水外流的阻力因素。方法选取经临床确诊的POAG病人20例(30眼)和经筛选的正常尸眼30只,采用透射电镜技术对房角组织进行超微结构形态学分析。结果实验组30眼中有27眼的集液管在Schlemm管外壁开口处存在电子致密物沉积,呈指纹状。电子致密物的数目与杯盘比(C/D)有正的直线相关关系(r=0.66,P<0.001);与年龄、术前眼压及视野缺损程度均无直线相关关系(r=0.03,P>0.50;r=-0.24,0.20<P<0.50;r=0.30,0.10<P<0.20)。在对照组30个标本的集液管在Schlemm管外壁开口处中均未观察到任何电子致密物等导致狭窄的因素。结论Schlemm管外壁尤其是集液管在Schlemm管外壁开口处的病变可能是形成POAG房水外流阻力的重要因素。 展开更多
关键词 青光眼 开角型 schlemm 组织病理学 超微结构
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Schlemm's管小梁切除术临床疗效观察(附13眼报告)
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作者 傅昆良 江玲 曾华科 《福建医药杂志》 CAS 2008年第1期28-28,共1页
目的探讨Schlemm's管小梁切除术对青光眼的临床疗效。方法选择13例双眼慢性青光眼,一侧眼为绝对期,另一侧眼为青光眼中晚期患者,共26只眼。13只绝对期青光眼施行Schlemm's管小梁切除术,另13只中晚期慢性青光眼行常规小梁切除术... 目的探讨Schlemm's管小梁切除术对青光眼的临床疗效。方法选择13例双眼慢性青光眼,一侧眼为绝对期,另一侧眼为青光眼中晚期患者,共26只眼。13只绝对期青光眼施行Schlemm's管小梁切除术,另13只中晚期慢性青光眼行常规小梁切除术。结果全部病例经1~3年随访观察,Schlemm's管小梁切除术眼,眼压控制均优于常规小梁切除术眼。除3只眼术后前房有少许出血外均未发生任何严重的并发症,眼压<18mmHg9只眼;眼压<25mmHg4只眼。结论Schlemm's管小梁切除术可为抗青光眼手术提供一项手术方式,供临床选择。 展开更多
关键词 schlemms 小梁切除术 青光眼
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Schlemm管引流联合复合式小梁切除术治疗外伤性青光眼 被引量:2
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作者 常新奇 孟海林 《河南外科学杂志》 2012年第6期31-32,共2页
目的探讨Schlemm管引流联合复合式小梁切除术治疗外伤性青光眼的可行性和疗效评价。方法对23例(23眼)因眼外伤房角后退继发开角型青光眼患者施行Schlemm管引流联合复合式小梁切除术,术后观察眼压、矫正视力、前房情况、术后并发症和滤... 目的探讨Schlemm管引流联合复合式小梁切除术治疗外伤性青光眼的可行性和疗效评价。方法对23例(23眼)因眼外伤房角后退继发开角型青光眼患者施行Schlemm管引流联合复合式小梁切除术,术后观察眼压、矫正视力、前房情况、术后并发症和滤过泡的形态等。术后随访6~24个月,平均(14.46±9.16)月。结果术后1 d、1周、1月、3月、6月、12月平均眼压分别为(8.7±3.19)mmHg、(9.14±4.62)mmHg、(13.62±3.10)mmHg、(13.77±4.11)mmHg、(14.55±6.02)mmHg、(15.98±5.12)mmHg。与术前平均眼压(31.73±8.66)mmHg比较差异均具有统计学意义(P均<0.05)。最末次随访平均眼压(16.41±4.25)mmHg,与术前平均眼压比较,差异具有统计学意义(t=13.547,P=0.000)。术后21眼眼压控制在正常范围,手术成功率91.30%。15眼(65.22%)形成功能性滤过泡,6只眼(26.09%)为非功能滤过泡,但眼压正常范围内。术后并发症主要是早期前房出血。结论Schlemm管引流联合复合式小梁切除术治疗外伤性青光眼安全有效,并发症少,具有良好临床应用前景。 展开更多
关键词 schlemm 小梁切除术 眼外伤
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Analogs of microgravity: the function of Schlemm's canal, intraocular pressure and autonomic nervous during the head-down tilt test in healthy subjects 被引量:2
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作者 Wei Chen Zhi-Qi Chen +3 位作者 Yan Xiang Chao-Hua Deng Hong Zhang Jun-Ming Wang 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2021年第9期1419-1423,共5页
AIM:To evaluate the ocular outcomes and to elucidate possible mechanisms underlying intraocular pressure(IOP)change following the head-down tilt(HDT)test.METHODS:The study included 21 participants at the Department of... AIM:To evaluate the ocular outcomes and to elucidate possible mechanisms underlying intraocular pressure(IOP)change following the head-down tilt(HDT)test.METHODS:The study included 21 participants at the Department of Ophthalmology of Tongji Hospital.Subjects received the test of I-care tonometry,enhanced depth imaging optical coherence tomography and heart rate variability(HRV)analysis before and after 15 min HDT test.The lumen area of Schlemm’s canal(SCAR),IOP,HRV were calculated.RESULTS:IOP increased significantly after 20°head down position from 14.0±3.0 to 17.0±3.3 mm Hg(P<0.001).SCAR decreased from 13449.0±5454.9μm^(2) at sitting condition to 9576.6±4130.9μm^(2) post 15 min HDT test.High frequency(HF)indices increased significantly from 1462±865 Hz at baseline to 2128±824 Hz.Heart rate(HR)decreased significantly from 76±11.48 to 70±11.52 bpm after the HDT.The linear regression analysis showed that the difference of HF and SCAR significantly correlated with each other during the HDT(R^(2)=20%,P=0.04).CONCLUSION:These outcomes perform the first evidence of the activation of autonomic nervous system of HDT may cause the collapse of Schlemm’s canal lumen,which in turn leading to the increased IOP. 展开更多
关键词 head-down tilt aqueous humor schlemms canal autonomic nervous system intraocular pressure
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Predictive Model for Corrosion Rate of Oil Tubes in CO_2/H_2S Coexistent Environment Part Ⅰ: Building of Model 被引量:5
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作者 李全安 白真权 +3 位作者 黄得志 张清 文九巴 李鹤林 《Journal of Southwest Jiaotong University(English Edition)》 2004年第2期141-147,共7页
Based on an analysis of the existing models of CO 2 corrosion in literatures and the autoclave simulative experiments, a predictive model of corrosion rate (r corr) in CO 2/H 2S corrosion for oil tubes has been ... Based on an analysis of the existing models of CO 2 corrosion in literatures and the autoclave simulative experiments, a predictive model of corrosion rate (r corr) in CO 2/H 2S corrosion for oil tubes has been established, in which r corr is expressed as a function of pH, temperature (T), pressure of CO 2 (P CO 2) and pressure of H 2S (P H 2S). The model has been verified by experimental data obtained on N80 steel. The improved features of the predictive model include the following aspects: (1) The influence of temperature on the protectiveness of corrosion film is taken into consideration for establishment of predictive model of the r corr in CO 2/H 2S corrosion. The Equations of scale temperature and scale factor are put forward, and they fit the experimental result very well. (2) The linear relationship still exists between ln r corr and ln P CO 2 in CO 2/H 2S corrosion (as same as that in CO 2 corrosion). Therefore, a correction factor as a function of P H 2S has been introduced into the predictive model in CO 2/H 2S corrosion. (3) The model is compatible with the main existing models. 展开更多
关键词 Predictive model CO 2/H 2s corrosion Corrosion rate scale temperature Oil tube
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Changes in Schlemm’s canal,trabecular meshwork,and relevant parameters in the early stage after SMILE of myopia patients 被引量:1
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作者 Dan-Dan Yang Zhi-Qi Chen +3 位作者 Wei Chen He Yin Jing-Kai Peng Jun-Ming Wang 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2022年第2期291-298,共8页
AIM:To observe the changes in Schlemm’s canal(SC),trabecular meshwork(TM),and anterior chamber relevant parameters after small incision lenticule extraction(SMILE) of myopia patients.METHODS:A total of 58 eyes from 3... AIM:To observe the changes in Schlemm’s canal(SC),trabecular meshwork(TM),and anterior chamber relevant parameters after small incision lenticule extraction(SMILE) of myopia patients.METHODS:A total of 58 eyes from 30 patients who underwent SMILE were divided into a low and moderate myopia group(group A,32 eyes) and a high myopia group(group B,26 eyes).The diameter and area of the SC,the width and thickness of TM obtained by CIRRUS HD-OCT5000,and the related anterior chamber parameters obtained by Pentacam anterior segment analysis system,accommodation amplitude(AMP) were observed pre-and postoperatively.The preoperative intraocular pressure(IOP) and postoperative correction of intraocular pressure(IOPcc) were measured.RESULTS:The diameter and area of the SC in the two groups were significantly increased postoperatively(all P<0.01).The TM width of the patients in the two groups were increased at 1mo after surgery(both P<0.01),but the TM thickness did not change(P>0.05).The corneal curvature,central anterior chamber depth,and anterior chamber volume decreased after SMILE surgery(all P<0.01).There was a weak negative correlation between the SC area change and AMP change in group A(r=-0.362,P<0.01).The postoperative IOP decreased after correction by Shah formula(P<0.05).CONCLUSION:SC and TM in myopia patients change in the early postoperative stage of SMILE and the IOP is decline. 展开更多
关键词 schlemms canal trabecular meshwork intraocular pressure MYOPIA small incision lenticule extraction
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Safety of gastric lavage using nasogastric ryle’s tube in pesticide poisoning 被引量:1
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作者 Uday Bhan Bhardwaj Anand Subramaniyan +2 位作者 Ashish Bhalla Navneet Sharma Surjit Singh 《Health》 2011年第7期401-405,共5页
Objective: Gastric lavage is mandatory irrespective of nature in all patients with acute poisoning in India. Present study was undertaken with aim whether lavage done using nasogastric Ryle’s tube and small aliquots ... Objective: Gastric lavage is mandatory irrespective of nature in all patients with acute poisoning in India. Present study was undertaken with aim whether lavage done using nasogastric Ryle’s tube and small aliquots of water or normal saline is safe. Patients and Methods: All the patients above 12 years of age admitted consecutively with pesticide ingestion or exposure between July 2004 to June 2005 were studied with respect to complications associated with lavage using Ryle’s tube. Forty five patients were admitted directly to our hospital and lavage was undertaken using Ryle’s tube (16F ) with 100 - 200 mL of aliquots till 1 - 1.5 liters of fluid was lavaged, with prophylactic endotracheal intubation in patients with Glasgow coma scale ( GCS) < 10 (group I). The incidence of complications related to lavage in group I was compared to that in 53 patients admitted during same period with pesticide poisoning but lavaged outside using nasogastric Ryle’s tube and referred to our institute (group II). Results: The significant complications observed in group I were significant drop in SaO2 (6 patients) laryngospasm, tachycardia, electrolyte imbalance and tube getting struck in throat (one each). In one patient in group I (had no prophylactic intubation though GCS 3) In group II, 7 had aspiration pneumonia (no prophylactic intubation). Other significant complication was drop in SaO2 during lavage. None of them had any serious life threatening complication. Conclusion: Gastric lavage carried out using nasogastric Ryle’s tube and small aliquots of water or normal saline is relatively safe in patients with pesticide poisoning when combined with prophylactic endotracheal intubation in patients with GCS < 10. In absence of prophylactic intubation, risk of aspiration is there. However aspiration pneumonia is generally mild and not life threatening. 展开更多
关键词 PEsTICIDE POIsONING GAsTRIC LAVAGE Nasogastric Ryle’s tube COMPLICATIONs
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H_(2)S在线监测装置研发及在锅炉水冷壁高温腐蚀防治中的应用 被引量:3
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作者 熊小鹤 谭厚章 +4 位作者 邱选兵 李传亮 王承亮 杨祖旺 郭古青 《电力科技与环保》 2024年第2期125-132,共8页
锅炉水冷壁高温腐蚀问题一直是影响锅炉安全运行的难题。为解决锅炉水冷壁高温腐蚀的主要媒介H_(2)S需要连续测量,但当前行业内缺乏能长期运行的H_(2)S在线监测装置问题,研发了基于可调谐二极管吸收光谱TDLAS原理测量锅炉水冷壁H_(2)S... 锅炉水冷壁高温腐蚀问题一直是影响锅炉安全运行的难题。为解决锅炉水冷壁高温腐蚀的主要媒介H_(2)S需要连续测量,但当前行业内缺乏能长期运行的H_(2)S在线监测装置问题,研发了基于可调谐二极管吸收光谱TDLAS原理测量锅炉水冷壁H_(2)S的监测装置,并使用装置在某300 MW等级电站锅炉上进行了示范应用,跟踪评估了该装置的性能。结果显示,基于TDLAS原理所研发的仪器在现场投运12个月以来保持稳定运行,装置在线监测结果显示炉内H_(2)S呈现脉冲式波动特点,H_(2)S浓度高时超过1600μL/L。监测中发现,炉内H_(2)S浓度与运行调整存在较密切的关系,在升负荷过程中,由2台磨转为3台磨运行时,前后墙23.60 m平台测点处H_(2)S浓度急剧增加,从46μL/L增至822μL/L,H_(2)S与脱硫塔入口SO_(2)没有显著的关联性。H_(2)S在线监测装置的成功研发可以实现锅炉主燃烧器区域关键参数的在线监测,并作为运行人员调整锅炉运行参数的主要依据,这对于锅炉高温腐蚀监测和锅炉数字化建设具有积极意义。 展开更多
关键词 锅炉 水冷壁 高温腐蚀 H_(2)s 还原性气氛
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Research on the inwall shot blasting of the S30432 high-pressure boiler tube
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作者 XU Songqian1),ZHANG Yuehong1),JIANG Chuanhai2) and HUANG Yanpin1) 1) Special Steel Technology Center,Research Institute,Baoshan Iron & Steel Co.,Ltd.,Shanghai 200940,China 2) School of Materials Science and Engineering,Shanghai Jiaotong University,Shanghai 200240,China 《Baosteel Technical Research》 CAS 2012年第1期44-52,共9页
Inwall shot blasting is a method of improving the surface hardness and high temperature oxidation resistance of the S30432 high-pressure boiler tube.The differences on residual stress,sub-grain size,micro-hardness and... Inwall shot blasting is a method of improving the surface hardness and high temperature oxidation resistance of the S30432 high-pressure boiler tube.The differences on residual stress,sub-grain size,micro-hardness and structure between the S30432 inwall shot-blasting tube produced by Baosteel with six technological process parameters and the imported super 304H were studied systematically by contrast test research.It has been demonstrated that the S30432 obtains a higher residual stress,a deeper distributed layer and a better sub-grain size of the inwall field shot-blasting layer;the martensite content of the shot-blasting surface was low;and micro-hardness and structure refinement were better.After 2000 h’ oxidation test under the 650℃/26MPa steam condition,steam oxidation resistance of the Baosteel steel tube shot-blasting surface was higher,the oxide layer was thinner,and was well combined with bulk material. 展开更多
关键词 s30432 tube shot blasting residual stress sub-grain size micro-hardness
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Surgical Management of Obstructive Urolithiasis in Small Ruminants by Tube Cystostomy in Chittagong, Bangladesh
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作者 Bibek Chandra Sutradhar Tuli Dey +1 位作者 Saroj Kumar Yadav Mohammad Bayazid Bostami 《Journal of Agricultural Science and Technology(A)》 2018年第2期89-98,共10页
The present study was conducted to evaluate minimally invasive tube cystostomy technique in goats and calves suffering from obstructive urolithiasis having intact and ruptured urinary bladder. This clinical study was ... The present study was conducted to evaluate minimally invasive tube cystostomy technique in goats and calves suffering from obstructive urolithiasis having intact and ruptured urinary bladder. This clinical study was carried out on 84 clinical cases (61 goats and 23 calves) based on the history, clinical signs and physical examination along with common laboratory techniques at the Chittagong Veterinary and Animal Sciences University during January 2015-December 2016. Physical parameters like heart rate, respiratory rate, rectal temperature and dehydration status of animals were noted and corrected abnormality before surgery. Some cases had slightly higher haemoglobin (Hb), packed cell volume (PCV) and uric acid and epithelial casts in urine. The study revealed that abnormal calcium-phosphorus ratio was predisposing the animals to urolithiasis. It was found that young ruminants (3-5 months) were most commonly affected in both species. All affected animals were male in this study, in which calves were not castrated but in goats 95.08% animals were castrated. Rupture of bladder was more common in calves as compared to goats. Postoperatively all cases were administered with broad-spectrum antibiotic, anti-inflammatory agent and caliculolytic agents like ammonium chloride. Tube cystostomy with Foley’s catheter was the most satisfactory technique for the management of obstructive urolithiasis in small ruminants. Postoperative complications were recorded only in four animals and remaining 80 animals had a normal recovery from tube cystostomy. Tube cystostomy is a simple, inexpensive and very effective procedure for the treatment of urolithiasis in ruminants. 展开更多
关键词 small ruminants Foley’s catheter tube cystostomy UROLITHIAsIs
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多因素影响下的S型管道冲刷腐蚀速率分析
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作者 马忠贞 张友军 +1 位作者 吕雪飞 甘树坤 《吉林化工学院学报》 CAS 2024年第1期43-50,共8页
S型管道应用于输运过程中的复杂地形,在上下游弯头处,会形成不同程度的冲刷腐蚀,造成安全隐患。为分析其腐蚀影响因素,建立S型管道腐蚀模型,采用ANSYS的Workbench平台搭建Fluent模块对不同影响因素下的腐蚀模型进行研究,创建数据传输,... S型管道应用于输运过程中的复杂地形,在上下游弯头处,会形成不同程度的冲刷腐蚀,造成安全隐患。为分析其腐蚀影响因素,建立S型管道腐蚀模型,采用ANSYS的Workbench平台搭建Fluent模块对不同影响因素下的腐蚀模型进行研究,创建数据传输,进而研究流体在流入弯管后各因素与冲蚀速率的关系。结果表明,S型管道冲刷腐蚀受到多因素的影响,尤其是下游弯头处的冲刷腐蚀更为明显。适当减小颗粒物直径、颗粒物质量流量,增大管径和弯径比可以减缓腐蚀及减小腐蚀区域。研究可为管道安全稳定运行提供理论依据。 展开更多
关键词 DPM s型管 冲刷腐蚀 腐蚀速率 数值模拟
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低比速水泵水轮机“S”形特性对尾水管最小压力敏感性研究
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作者 王昭力 李远余 +3 位作者 樊红刚 郭连恒 邓清树 张美琴 《大电机技术》 2024年第5期58-65,共8页
水泵水轮机“S”形特性对机组的水力过渡过程有着要的影响,“S”形特性的优劣是判定模型转轮研发成功与否的关键指标之一,对低比速水泵水轮机显得更为重要。为更深入研究转轮“S”形特性、模型转轮优化设计、水力过渡过程三者间联系,本... 水泵水轮机“S”形特性对机组的水力过渡过程有着要的影响,“S”形特性的优劣是判定模型转轮研发成功与否的关键指标之一,对低比速水泵水轮机显得更为重要。为更深入研究转轮“S”形特性、模型转轮优化设计、水力过渡过程三者间联系,本文定义一种对“S”特性曲线定点定量的分析方法,利用不同试验特性曲线,通过水力过渡过程仿真分析加以判定,对“S”形曲线量化分析以探索三者之间的内在联系。研究表明全特性曲线中间等开度线“S”区弯曲程度对尾水管最小压力敏感性最强,等开度线在“S”区内单位流量与单位转速的比值越大,同一等开度线上飞逸单位流量越大,对提高尾水管进口最小压力越有利;叶片型式和活动导叶翼型优化设计可在一定程度上改善“S”形特性品质,提高甩负荷时尾水管最小压力值。本研成果在低比速水泵水轮机模型转轮研发和水力过渡过程优化计算方面均具有一定参考意义。 展开更多
关键词 低比速 水泵水轮机 s”形特性 过渡过程 尾水管最小压力
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Preparation and Anti-coking Property of SiO_2/S Coating on HP40 Tube
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作者 周建新 徐宏 +3 位作者 张莉 刘京雷 戚学贵 彭博 《过程工程学报》 EI CAS CSCD 北大核心 2007年第6期1243-1248,共6页
SiO2/S coating was prepared on the inner surface of an HP40 tube using dimethyldisulfide and tetraethylorthosilicate by atmospheric pressure chemical vapor deposition(APCVD) to alleviate catalytic coking on the inner ... SiO2/S coating was prepared on the inner surface of an HP40 tube using dimethyldisulfide and tetraethylorthosilicate by atmospheric pressure chemical vapor deposition(APCVD) to alleviate catalytic coking on the inner surface of radiant tube for ethylene production in petrochemical plants.The comparative coking experiments with the coated and uncoated HP40 tubes were carried out under the same cracking conditions.SiO2/S coating was compact and had excellent anti-coking property.The coke on the coated HP40 tube was about 22% of that on the uncoated HP40 tube,and only small granular coke was deposited on the coated HP40 tube.However,the filamentous coke formed on the uncoated HP40 tube.The thermal stability of SiO2/S coating was satisfactory at cracking temperature,and the anti-coking property of SiO2/S coating was still over 60% after 3 coking and decoking cycles. 展开更多
关键词 HP40管 焦炭 二氧化硅/硫被覆 大气压力化学汽相沉积 制备 抗成焦性
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S型皮托管对向和非对向测量方法准确度实验研究
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作者 张乐垚 张亮 +3 位作者 郭素娜 郭虎林 鲁贵祥 孔令彩 《计量学报》 CSCD 北大核心 2024年第6期864-872,共9页
S型皮托管的对向和非对向测量方法准确度在不同工况下有较大差异。通过风洞实流实验对风速、流速攻角和结构参数对S型皮托管对向和非对向测量方法准确度的影响进行了研究。结果表明:风速由5 m/s变化至30 m/s时,在不同流速攻角下S型皮托... S型皮托管的对向和非对向测量方法准确度在不同工况下有较大差异。通过风洞实流实验对风速、流速攻角和结构参数对S型皮托管对向和非对向测量方法准确度的影响进行了研究。结果表明:风速由5 m/s变化至30 m/s时,在不同流速攻角下S型皮托管对向和非对向测量准确度最大差异超过10%;对向和非对向测量中静压孔的压力变化是皮托管在较大流速攻角下造成测量误差的主因;外径较小、总静压孔距较大、测量端弯曲角度在15°至30°间、取压孔内径更小的S型皮托管在对向和非对向测量中都有更高的测量准确度;俯仰角取正值时对向测量准确度全面优于非对向测量,在俯仰角和偏航角同为45°时测量准确度差异达到最大值,大于70%。 展开更多
关键词 流量测量 s型皮托管 烟道流量 对向测量 非对向测量 测量准确度
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水泵水轮机S特性对相继甩尾水最小压力的影响
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作者 王皓臻 俞晓东 +2 位作者 林文雯 李朋宇 刘昌太 《水力发电学报》 CSCD 北大核心 2024年第6期113-122,共10页
为探究水泵水轮机全特性曲线S特性与尾水压力最小值的联系,基于新丰抽水蓄能电站的过渡过程数值仿真模型模拟了尾水最不利相继甩工况。通过调整机组运行轨迹线附近开度线斜率,对比分析并总结S区形状变化对相继甩工况尾水压力极值的影响... 为探究水泵水轮机全特性曲线S特性与尾水压力最小值的联系,基于新丰抽水蓄能电站的过渡过程数值仿真模型模拟了尾水最不利相继甩工况。通过调整机组运行轨迹线附近开度线斜率,对比分析并总结S区形状变化对相继甩工况尾水压力极值的影响规律,提出了一种图形指标,能够应用在抽蓄前期设计中评价S特性对尾水压力影响优劣,并验证其准确性。结果表明,相继甩工况后甩机组流量变化率第一波下降时,机组运行轨迹线呈现完整倒S形,S区形状变化改变了机组流量变化率的大小,导致出现在靠近轨迹线S形下拐点前的尾水压力极值发生变化,给出的图形指标形状越趋近于竖向细长的规则长方形,相应的尾水最小压力的改善效果越好。 展开更多
关键词 抽水蓄能电站 水泵水轮机全特性曲线 s特性 相继甩 尾水最小压力
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海上热采油田H_(2)S成因机理研究
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作者 尹洪超 张伟森 +1 位作者 冉兆航 张莹 《化学工程师》 CAS 2024年第6期46-50,共5页
随着我国海上稠油油田的深入开发,热采蒸汽驱规模逐步扩大,相应的H_(2)S系列问题也愈发凸显。H_(2)S不仅危害人的健康,还能腐蚀金属设备,严重影响生产的安全平稳运行。本文以L稠油油田为例,在调研目标油田储层概况和H_(2)S生成情况的基... 随着我国海上稠油油田的深入开发,热采蒸汽驱规模逐步扩大,相应的H_(2)S系列问题也愈发凸显。H_(2)S不仅危害人的健康,还能腐蚀金属设备,严重影响生产的安全平稳运行。本文以L稠油油田为例,在调研目标油田储层概况和H_(2)S生成情况的基础上,通过黄金管热模拟实验、色谱分析等方式,探究海上热采油田的H_(2)S的成因机理。实验结果表明,L稠油油田H_(2)S生成的物源主要为原油和地层水,岩屑能够起到催化作用;温度和时间是影响H_(2)S的主控因素,温度越高、时间越长,生成的H_(2)S量越高;L油田H_(2)S生成的主要原因是发生了地层水热裂解、硫酸盐还原反应。该研究成果能够为其他热采油田的H_(2)S成因研究提供探索思路,为油田H_(2)S治理指明方向。 展开更多
关键词 热采油田 H_(2)s 黄金管热模拟实验 物源 温度 机理
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一种S波段国产GaN固态雷达发射机
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作者 姚黄 毛荣鑫 《火控雷达技术》 2024年第4期100-105,共6页
为了应对国产化需求,设计了一款工作频点在2.7到2.9 GHz的国产氮化镓(GaN)固态雷达发射机。设计的发射系统A、B两路发射机各自可以单独工作。当一路工作出现故障,能够自动切换到另外一路,不会造成中断停机。发射系统的组成部件位于发射... 为了应对国产化需求,设计了一款工作频点在2.7到2.9 GHz的国产氮化镓(GaN)固态雷达发射机。设计的发射系统A、B两路发射机各自可以单独工作。当一路工作出现故障,能够自动切换到另外一路,不会造成中断停机。发射系统的组成部件位于发射机柜和电源机柜里,通过接收来自发射监控系统的控制命令,执行发射监控系统的命令并完成对发射电源及发射组件的控制,完成功率数据、电流电压等数据的采集,同时也将本系统中各主要部件的工作状态和故障信息回馈监控系统。 展开更多
关键词 s波段 国产GaN功率管 固态雷达发射机 发射系统 数据采集 监控系统
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梨自交不亲和及其亲和突变品种花柱内S_4(S_4^(SM))基因的表达与作用的比较 被引量:26
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作者 张绍铃 平塚伸 +2 位作者 徐国华 房经贵 刘友良 《Acta Botanica Sinica》 CSCD 2001年第11期1172-1178,共7页
提取梨 (PyrusserotinaRehd .)自交不亲和品种“二十世纪”(基因型为S2 S4 )、自交亲和的突变品种“奥嗄二十世纪”(S2 SSM4 ,SM =Stylar_partmutant;花柱部分突变 )及其亲和后代花柱的可溶性蛋白。经等电聚焦电泳 (IEF_PAGE)分析表明 ... 提取梨 (PyrusserotinaRehd .)自交不亲和品种“二十世纪”(基因型为S2 S4 )、自交亲和的突变品种“奥嗄二十世纪”(S2 SSM4 ,SM =Stylar_partmutant;花柱部分突变 )及其亲和后代花柱的可溶性蛋白。经等电聚焦电泳 (IEF_PAGE)分析表明 ,“奥嗄二十世纪”及其后代花柱仍存在SSM4 蛋白 ,但其含量逐代减少 ,同时发现“奥嗄二十世纪”的SSM4 基因仅在柱头表达 ,而“二十世纪”的S4 基因表达的部位除了柱头外 ,还包括花柱上部及花柱下部 ,且表达量呈现从柱头到花柱下部下降的趋势。S蛋白经等电聚焦电泳的凝胶板进行RNase活性染色处理 ,也得到相同的结果。从花柱 (包括柱头 )中纯化出的S蛋白经SDS_PAGE电泳后进行RNase活性染色的结果表明 ,S4 与SSM4 蛋白的分子量相近 (约 30kD) ,并且均具有RNase活性。进一步以酵母RNA为基质测定的比活性也基本相等 ,约为 2 75U·min-1·mg-1蛋白。在离体条件下 ,上述两种S蛋白 (S_RNase)也以相同的程度抑制S4 或SSM4 花粉发芽及花粉管伸长。研究证明 ,自交亲和突变品种“奥嗄二十世纪”的SSM4 基因也具有原始自交不亲和品种“二十世纪”S4 基因的功能。因此 ,其自交亲和的原因可归结为SSM4 基因的表达量较少及SSM4 基因仅在柱头中表达的缘故。 展开更多
关键词 自交不亲和性 s基因 s蛋白 花粉管伸长 花柱 突变品种
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