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Feature Extraction of Sectorial Scan Image of Thick-Walled Electron Beam Welding Seam Based on Principal Component Analysis
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作者 Tie Gang Yilin Luan Chi Zhang 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2017年第6期45-51,共7页
A feature extraction method was proposed to sectorial scan image of Ti-6Al-4V electron beam welding seam based on principal component analysis to solve problem of high-dimensional data resulting in timeconsuming in de... A feature extraction method was proposed to sectorial scan image of Ti-6Al-4V electron beam welding seam based on principal component analysis to solve problem of high-dimensional data resulting in timeconsuming in defect recognition. Seven features were extracted from the image and represented 87. 3% information of the original data. Both the extracted features and the original data were used to train support vector machine model to assess the feature extraction performance in two aspects: recognition accuracy and training time. The results show that using the extracted features the recognition accuracy of pore,crack,lack of fusion and lack of penetration are 93%,90.7%,94.7% and 89.3%,respectively,which is slightly higher than those using the original data. The training time of the models using the extracted features is extremely reduced comparing with those using the original data. 展开更多
关键词 electron beam welding phased array ultrasonic sectorial scan image feature extraction principal component analysis
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Progress of research in the application of ultrasound technology for the treatment of Alzheimer’s disease
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作者 Qiuquan Cai Lianghui Meng +5 位作者 Meina Quan Ling Wang Jing Ren Chenguang Zheng Jiajia Yang Dong Ming 《Neural Regeneration Research》 SCIE CAS 2025年第10期2823-2837,共15页
Alzheimer’s disease is a common neurodegenerative disorder defined by decreased reasoning abilities,memory loss,and cognitive deterioration.The presence of the blood-brain barrier presents a major obstacle to the dev... Alzheimer’s disease is a common neurodegenerative disorder defined by decreased reasoning abilities,memory loss,and cognitive deterioration.The presence of the blood-brain barrier presents a major obstacle to the development of effective drug therapies for Alzheimer’s disease.The use of ultrasound as a novel physical modulation approach has garnered widespread attention in recent years.As a safe and feasible therapeutic and drug-delivery method,ultrasound has shown promise in improving cognitive deficits.This article provides a summary of the application of ultrasound technology for treating Alzheimer’s disease over the past 5 years,including standalone ultrasound treatment,ultrasound combined with microbubbles or drug therapy,and magnetic resonance imaging-guided focused ultrasound therapy.Emphasis is placed on the benefits of introducing these treatment methods and their potential mechanisms.We found that several ultrasound methods can open the blood-brain barrier and effectively alleviate amyloid-βplaque deposition.We believe that ultrasound is an effective therapy for Alzheimer’s disease,and this review provides a theoretical basis for future ultrasound treatment methods. 展开更多
关键词 Alzheimer’s disease blood-brain barrier DRUGs magnetic resonance imaging-guided focused ultrasound MICROBUBBLEs scanning ultrasound ULTRAsOUND ultrasound stimulation
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EFFECT OF THE TOTAL SAPONIN OF DIPSACUS ASPER ON INTRACELLULAR FREE CALCIUM CONCENTRATION IN THE CELLULAR MODEL OF ALZHEIMER'S DISEASE-SCANNING CONFOCAL MICROSCOPY 被引量:2
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作者 钱亦华 任惠民 +3 位作者 胡海涛 刘勇 杨广德 王春梅 《Academic Journal of Xi'an Jiaotong University》 2001年第2期159-163,共5页
Objective To study the effect of ginsenoside Rb1 and total saponin of dipsacus asper on intracellular free calcium concentration mediated by β amyloid protein.So as to lay a foundation for developing effective Chines... Objective To study the effect of ginsenoside Rb1 and total saponin of dipsacus asper on intracellular free calcium concentration mediated by β amyloid protein.So as to lay a foundation for developing effective Chinese traditional medicine to treat Alzheimer’s disease.Methods The technique of laser scanning confocal microscopy combining primary cultured neurons was adopted to quantitatively analyze the change of [Ca 2+ ] i.Results The [Ca 2+ ] i of primary cultured hippocampal neurons was nmol·L -1 on basal levels.Control group showed obvious change of calcium vibration,[Ca 2+ ] i was elevated to nmol·L -1 .The peak of [Ca 2+ ] i of Rb1 group reached nmol·L -1 and was lower than that of control group .The tSDA group displayed distinct change of calcium vibration too,and [Ca 2+ ] i reached nmol·L -1 .There was a significant difference in [Ca 2+ ] i between control and tSDA group .Conclusion The research indicated that one of mechanisms by which Rb1 and tSDA protected the neurons was to maintain the balance of [Ca 2+ ] i. 展开更多
关键词 cultured neurons β amyloid protein Alzheimer’s disease scanning confocal microscopy
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用Z—Scan法高精度测量非线性折射率 被引量:1
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作者 杨向明 杨淼 +1 位作者 曲士良 李俊庆 《哈尔滨工业大学学报》 EI CAS CSCD 北大核心 1995年第1期41-44,共4页
介绍了一种简单而灵敏的单光束测量非线性折射率n2大小和符号的实验方法(Z—Scan)。样品在聚焦的高斯光束z方向上移动,得到远场通过小孔后的透射率曲线,由该曲线很容易计算出n2。使用CWCO2激光器对InSb样品进行... 介绍了一种简单而灵敏的单光束测量非线性折射率n2大小和符号的实验方法(Z—Scan)。样品在聚焦的高斯光束z方向上移动,得到远场通过小孔后的透射率曲线,由该曲线很容易计算出n2。使用CWCO2激光器对InSb样品进行测量,得到该样品相对10.6μm波长的非线性折射率为1.80×10-4esu。 展开更多
关键词 非线性 折射率 Z-scan 测量
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Scanning electron microscopy coupled with energydispersive X-ray spectrometry for quick detection of sulfuroxidizing bacteria in environmental water samples 被引量:1
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作者 SUN Chengjun JIANG Fenghua +5 位作者 GAO Wei LI Xiaoyun YU Yanzhen YIN Xiaofei WANG Yong DING Haibing 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2017年第1期185-191,共7页
Detection of sulfur-oxidizing bacteria has largely been dependent on targeted gene sequencing technology or traditional cell cultivation, which usually takes from days to months to carry out. This clearly does not mee... Detection of sulfur-oxidizing bacteria has largely been dependent on targeted gene sequencing technology or traditional cell cultivation, which usually takes from days to months to carry out. This clearly does not meet the requirements of analysis for time-sensitive samples and/or complicated environmental samples. Since energy-dispersive X-ray spectrometry(EDS) can be used to simultaneously detect multiple elements in a sample, including sulfur, with minimal sample treatment, this technology was applied to detect sulfur-oxidizing bacteria using their high sulfur content within the cell. This article describes the application of scanning electron microscopy imaging coupled with EDS mapping for quick detection of sulfur oxidizers in contaminated environmental water samples, with minimal sample handling. Scanning electron microscopy imaging revealed the existence of dense granules within the bacterial cells, while EDS identified large amounts of sulfur within them. EDS mapping localized the sulfur to these granules. Subsequent 16S rRNA gene sequencing showed that the bacteria detected in our samples belonged to the genus Chromatium, which are sulfur oxidizers. Thus, EDS mapping made it possible to identify sulfur oxidizers in environmental samples based on localized sulfur within their cells, within a short time(within 24 h of sampling). This technique has wide ranging applications for detection of sulfur bacteria in environmental water samples. 展开更多
关键词 sulfur bacteria energy-dispersive X-ray spectrometry scanning electron microscopy bacteria detection environmental water samples 16s rRNA sequencing
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SCAN3000NT/S9000中小型集散控制系统及其应用
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作者 于泓 《山西经济管理干部学院学报》 2002年第3期48-49,共2页
本文以锅炉实施计算机集散控制工程为实例 ,介绍了计算机集散控制系统工程的控制方案组态方法和工作步骤。
关键词 集散控制 组态 软件 锅炉 scan3000NT/s9000中小型集散控制系统
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Ultrafast cyclic voltammetry with asymmetrical potential scan
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作者 Zhi Yong Guo Xiang Qin Lin 《Chinese Chemical Letters》 SCIE CAS CSCD 2008年第1期85-88,共4页
Based on the perfect ohmic drop compensation by online electronic positive feedback, ultrafast cyclic voltammetry with asymmetrical potential scan is achieved for the first time, with the reduction of anthracene actin... Based on the perfect ohmic drop compensation by online electronic positive feedback, ultrafast cyclic voltammetry with asymmetrical potential scan is achieved for the first time, with the reduction of anthracene acting as the test system. Compared with the traditional cyclic voltammetry utilizing symmetrical triangular waveform as the excitation one, the new method allows a simpler approach to mechanistic analysis of ultrafast chemical reactions coupled with a charge transfer. And perhaps more important, it also provides a way to eliminate the interference of the adsorbed product in dynamic monitoring. 2007 Zhi Yong Guo. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved. 展开更多
关键词 Ultrafast cyclic voltammetry Asymmetrical potential scan MV/s scan rates
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Assessing gestational age of babies: Performance of obstetric ultrasound scan compared to that from the combination of Naegle’s rule and Dubowitz score in the 21st century
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作者 Baba Usman Ahmadu 《Natural Science》 2013年第8期32-35,共4页
Background: Some researchers have suggested that when Naegle’s rule (NR) and Dubowitz score (DS) are combined, it could out-perform obstetric ultrasound scan (USS). Others still believe that obstetric USS alone is st... Background: Some researchers have suggested that when Naegle’s rule (NR) and Dubowitz score (DS) are combined, it could out-perform obstetric ultrasound scan (USS). Others still believe that obstetric USS alone is still effective relative to the combination of NR rule and DS in assessing the gestational age (GA) of babies. Objectives: To determine and compare the GA of babies using obstetric USS, NR and DS;and to provide relevant public health information on obstetric USS in the 21st century. Methods: Subjects were selected using systematic random sampling and the GA of babies was determined using obstetric USS, NR, and DS. Statistical package for social science (SPSS) statistical software version 16, Illinois, Chicago USA was used for all data analysis. Results: Eightyfive mother-baby pairs were studied. Forty-four babies (52%) were males and 41 (48%) females. Sixty four (75%) were term with a mean (SD) BW of 3.02 (0.59) at 95%CI (2.89 -?3.14) kg. The overall mean GA of the babies was 38.49 (2.89) at 95%CI (38.14 -?38.85) weeks. The mean GA using obstetric USS, NR and DS were 38.52 (1.98) at 95%CI (38.14 -?38.99), 38.09 (4.13) at 95%CI (37.20-?38.99) and 38.82 (2.02) at 95%CI (38.39 -?39.26), but comparison of these means was not significant (p = 0.256). Combined mean GA by NR and DS was 38.46 (3.26) at 95%CI (37.96 -?38.95). Comparing this mean with mean GA obtained by obstetric USS was also not significant (p = 0.885). Conclusion: The GA assessments by Obstetric USS, NR and DS were all reliable, and Obstetric USS performed effectively relative to combined NR and DS. 展开更多
关键词 GEsTATIONAL Age Babies OBsTETRIC Ultrasound scan Naegle’s RULE Dubowitz sCORE Maiduguri NIGERIA
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Opisthorchiasis-associated biliary stones:Light and scanning electron microscopic study
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作者 BanchobSripa PipatphongKanla +1 位作者 PoonsiriSinawat MelissaR.Haswell-Elkins 《World Journal of Gastroenterology》 SCIE CAS CSCD 2004年第22期3318-3321,共4页
AIM:Biliary stones are frequently encountered in areas endemic for opisthorchiasis in Thailand.The present study was to describe the prevalence and pathogenesis of these stones. METHODS:Gallstones and/or common bile d... AIM:Biliary stones are frequently encountered in areas endemic for opisthorchiasis in Thailand.The present study was to describe the prevalence and pathogenesis of these stones. METHODS:Gallstones and/or common bile duct stones and bile specimens from 113 consecutive cholecystectomies were included.Bile samples,including sludge and/or microcalculi,were examined for Opisthorchis viverrinieggs, calcium and bilirubin.The stones were also processed for scanning electron microscopic(SEM)study. RESULTS:Of the 113 cases,82 had pigment stones,while one had cholesterol stones.The other 30 cases had no stones.Most of the stone cases(76%,63/83)had multiple stones,while the remainder had a single stone.Stones were more frequently observed in females.Bile examination was positive for O.viverrini eggs in 50% of the cases studied.Aggregates of calcium bilirubinate precipitates were observed in all cases with sludge.Deposition of calcium bilirubinate on the eggshell was visualized by special staining.A SEM study demonstrated the presence of the parasite eggs in the stones.Numerous crystals, morphologically consistent with calcium derivatives and cholesterol precipitates,were seen. CONCLUSION:Northeast Thailand has a high prevalence of pigment stones,as observed at the cholecystectomy,and liver fluke infestation seems involved in the pathogenesis of stone formation. 展开更多
关键词 Adolescent Adult Aged Aged 80 and over Animals Female GALLsTONEs Humans Male Microscopy Electron scanning Middle Aged OPIsTHORCHIAsIs OPIsTHORCHIs purification Prevalence Research support Non-U.s. Gov't Thailand
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Fazari’s Sign in Ultrasound Scan of Morbid Adherent Placenta/Placenta Accreta Spectrum (MAP/PAS) and Fazari’s Triad during (MAP/PAS) Surgery
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作者 Atif Bashir Eltayeb Fazari Zeinabsadat Tabatabaei Hakim 《Open Journal of Obstetrics and Gynecology》 2020年第4期599-603,共5页
Morbid Adherent Placenta (MAP)/Placenta Accreta Spectrum (PAS) is a serious diagnosis which has a risk of complications. Ultrasound scan helps in early diagnosis and has great value in further confirmation and follow ... Morbid Adherent Placenta (MAP)/Placenta Accreta Spectrum (PAS) is a serious diagnosis which has a risk of complications. Ultrasound scan helps in early diagnosis and has great value in further confirmation and follow up. Observed new clinical sign and associated clinical triad are discussed here. 展开更多
关键词 MORBID Adherent PLACENTA (MAP)/Placenta Accreta spectrum (PAs) Ultrasound scan stair step sIGN Fazari’s TRIAD
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Mineral Particles Found on the Hairs of Holy Maria-Magdalena Studied by Scanning Electron Microscopy and Elemental Analysis
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作者 Gérard Lucotte 《Open Journal of Applied Sciences》 2020年第3期41-59,共19页
The presumed hairs of Holy Maria-Magdalena are studied here for mineral particles found on their surfaces, by the techniques of scanning electron microscopy coupled with energy dispersive X-ray. Exploration by these t... The presumed hairs of Holy Maria-Magdalena are studied here for mineral particles found on their surfaces, by the techniques of scanning electron microscopy coupled with energy dispersive X-ray. Exploration by these techniques of the hair surfaces allows us to observe and study some marble fragments that can originate from the walls of the sarcophagus in which Maria-Magdalena’s remains were kept. These new findings support the authenticity of the hair as traditionally reported in the French “tradition des Saints de Provence”. 展开更多
关键词 Maria-Magdalena’s HAIR scanning Electron Microscopy Energy Disper-sive X-Ray MARBLE FRAGMENTs MINERAL Particles
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CT Scan of the Foot in Patients with Chronic Non-Healing Diabetic Foot Ulcer
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作者 M. Rubina Fathimaa Arcot Rekha 《Case Reports in Clinical Medicine》 2020年第11期335-342,共8页
<strong>Background:</strong> Diabetes mellitus is a chronic disease where there is an increased blood sugar level in the body which is either caused due to inability of the pancreas to secrete insulin or t... <strong>Background:</strong> Diabetes mellitus is a chronic disease where there is an increased blood sugar level in the body which is either caused due to inability of the pancreas to secrete insulin or the body’s inability to utilize it. The prevalence of diabetes mellitus is growing rapidly worldwide. Statistics show that in the year 2014, there were a total of 422 million cases of DM. Diabetes mellitus is a major cause of heart attacks, kidney failure, blindness and leg amputations. Diabetic foot ulcers are quite common and are estimated to affect nearly 15% of all diabetic patients during their lifetime. In long standing diabetic patients with chronic non-healing ulcers, bony changes or deformities are not uncommon. These bony changes can be identified using CT scans. <strong>Materials and Methods:</strong> An observational study was conducted on a total of 40 patients with chronic non-healing ulcer attending the surgery outpatient department of Saveetha Medical College, Chennai, Tamilnadu. The CT-scans of their foot were observed for deformities or bony changes. <strong>Results:</strong> Out of 40 patients, 67.5% were males and 32.5% were females. A maximum number of subjects fell under the age group of 51 - 60 years. The most common site of the ulcer was found to be in the plantar surface of big toe (53%). Among the 40 patients, 33 of them were found to have bony abnormalities on the CT scan of foot and no apparent changes were seen in the rest. Bone erosions (35%), osteopenic changes (22.5%), Charcot’s joint (2.5%), osteophyte formation (12.5) and reduced joint space (10%) were the predominant changes observed on the CT scans of the study population. 展开更多
关键词 Diabetic Foot Ulcer Bony Abnormalities CT scan Bone Erosions Charcot’s Joint Osteophyte Formation Reduced Joint space Osteopenic Changes Plantar surface of Big Toe
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Microscopic growth mechanism and edge states of monolayer 1T'-MoTe_(2)
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作者 赵海鹏 刘隐 +7 位作者 杨胜国 林陈昉 陈明星 Kai Braun 罗心仪 李思宇 潘安练 王笑 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期605-611,共7页
Transition metal ditellurides(TMTDs)have versatile physical properties,including non-trivial topology,Weyl semimetal states and unique spin texture.Controlled growth of high-quality and large-scale monolayer TMTDs wit... Transition metal ditellurides(TMTDs)have versatile physical properties,including non-trivial topology,Weyl semimetal states and unique spin texture.Controlled growth of high-quality and large-scale monolayer TMTDs with preferred crystal phases is crucial for their applications.Here,we demonstrate the epitaxial growth of 1T'-MoTe_(2) on Au(111)and graphitized silicon carbide(Gr/SiC)by molecular beam epitaxy(MBE).We investigate the morphology of the grown1T'-MoTe_(2) at the atomic level by scanning tunnelling microscopy(STM)and reveal the corresponding microscopic growth mechanism.It is found that the unique ordered Te structures preferentially deposited on Au(111)regulate the growth of monolayer single crystal 1T'-MoTe_(2),while the Mo clusters were preferentially deposited on the Gr/SiC substrate,which impedes the ordered growth of monolayer MoTe_(2).We confirm that the size of single crystal 1T'-MoTe_(2) grown on Au(111)is nearly two orders of magnitude larger than that on Gr/SiC.By scanning tunnelling spectroscopy(STS),we observe that the STS spectrum of the monolayer 1T'-MoTe_(2) nano-island at the edge is different from that at the interior,which exhibits enhanced conductivity. 展开更多
关键词 transition metal ditellurides 1T'-MoTe_(2) microscopic growth mechanism scanning tunneling microscopy/spectroscopy(sTM/s)
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Single-center retrospective study of the diagnostic value of doubleballoon enteroscopy in Meckel’s diverticulum with bleeding
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作者 Tian He Chao Yang +10 位作者 Jing Wang Ji-Sheng Zhong Ai-Hua Li Ya-Jing Yin Li-Ling Luo Chun-Mei Rao Nian-Fen Mao Qiang Guo Zan Zuo Wen Zhang Ping Wan 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第4期1043-1054,共12页
BACKGROUND The study aimed to analyze the characteristic clinical manifestations of patients with intestinal disease Meckel’s diverticulum(MD)complicated by digestive tract hemorrhage.Moreover,we aimed to evaluate th... BACKGROUND The study aimed to analyze the characteristic clinical manifestations of patients with intestinal disease Meckel’s diverticulum(MD)complicated by digestive tract hemorrhage.Moreover,we aimed to evaluate the value of double-balloon enteroscopy(DBE)in MD diagnosis and the prognosis after laparoscopic diverticula resection.AIM To evaluate the value of DBE in the diagnosis and the prognosis after laparoscopic diverticula resection for MD with bleeding.METHODS The study retrospectively analyzed relevant data from 84 MD patients treated between January 2015 and March 2022 and recorded their clinical manifestations,auxiliary examination,and follow-up after laparoscopic resection of diverticula.RESULTS(1)Among 84 MD patients complicated with hemorrhage,77 were male,and 7 were female with an average age of 31.31±10.75 years.The incidence was higher in men than in women of different ages;(2)Among the 84 MD patients,65(78.40%)had defecated dark red stools,and 50(58.80%)had no accompanying symptoms during bleeding,indicating that most MD bleeding appeared a dark red stool without accompanying symptoms;(3)The shock index of 71 patients(85.20%)was<1,suggesting that the blood loss of most MD patients was less than 20%–30%,and only a few patients had a blood loss of>30%;(4)The DBE-positive rate was 100%(54/54),99mTcpertechnetate-positive scanning rate was 78%(35/45)compared with capsule endoscopy(36%)and small intestine computed tomography(19%).These results suggest that DBE and 99mTc-pertechnetate scans had significant advantages in diagnosing MD and bleeding,especially DBE was a highly precise examination method in MD diagnosis;(5)A total of 54 MD patients with hemorrhage underwent DBE examination before surgery.DBE endoscopy revealed many mucosal manifestations including normal appearance,inflammatory changes,ulcerative changes,diverticulum inversion,and nodular hyperplasia,with ulcerative changes being the most common(53.70%).This suggests that diverticular mucosal ulcer was the main cause of MD and bleeding;and(6)Laparoscopic dissection of diverticulae was performed in 76 patients,The patients who underwent postoperative follow-up did not experience any further bleeding.Additionally,follow-up examination of the 8 cases who had declined surgery revealed that 3 of them experienced a recurrence of digestive tract bleeding.These findings indicate that laparoscopic diverticula resection in MD patients complicated by bleeding had a favorable prognosis.CONCLUSION Bleeding associated with MD was predominantly observed in male adolescents,particularly at a young age.DBE was a highly precise examination method in MD diagnosis.Laparoscopic diverticula resection effectively prevented MD bleeding and had a good prognosis. 展开更多
关键词 Meckel’s diverticulum with bleeding Double-balloon colonoscopy 99mTc-pertechnetate scanning Capsule endoscopy Ectopic gastric mucosa
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Scanning the Year's Half:Hotspot Issues
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《China Textile》 2008年第8期18-24,共7页
The textile industry is growing at a slow speed against backdrop of outrageous rise in raw materials, energy, wages, yuan’s appreciation etc.. Three hot issues are more obviously brought into spotlight to be seen as ... The textile industry is growing at a slow speed against backdrop of outrageous rise in raw materials, energy, wages, yuan’s appreciation etc.. Three hot issues are more obviously brought into spotlight to be seen as most important factors that weigh a lot on the economic growth during the first half of the year and defi nitely the second half to come.A half of 2008 has elapsed, and the fore part of the year is mingled with hopes and worries, but the industry has managed to voyage on in the troubled waters. Reviewing the situation in perspectives, [[China Textile]] has summed up three hotspot issues that played protagonists in China’s textile industry: Firstly, outside-in sales from outbound shipment to homebound march on, secondly, the industry’s development is restricted by fund shortage; thirdly, the industrial adjustment and production relocation are still in progress. 展开更多
关键词 scanning the Year’s Half
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AMSR2辐射率资料同化对台风“山神”分析和预报的影响研究 被引量:11
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作者 杨春 闵锦忠 刘志权 《大气科学》 CSCD 北大核心 2017年第2期372-384,共13页
在WRFDA-3DVar(Weather Research and Forecasting model’s 3-dimensional variational data assimilation)的框架下,添加了新的探测器AMSR2(Advanced Microwave Scanning Radiometer 2)微波辐射率资料的同化模块,实现了AMSR2辐射率资... 在WRFDA-3DVar(Weather Research and Forecasting model’s 3-dimensional variational data assimilation)的框架下,添加了新的探测器AMSR2(Advanced Microwave Scanning Radiometer 2)微波辐射率资料的同化模块,实现了AMSR2辐射率资料在中小尺度同化系统中的有效使用。台风"山神"(Son-Tinh)直接同化AMSR2资料的个例试验结果表明,AMSR2资料可以很好的探测出台风的形态,并且与没有同化该资料的控制试验相比,同化AMSR2辐射率资料可以有效提高模式分析场的质量,进一步提高了台风中心气压,最大风速和台风路径的预报。 展开更多
关键词 微波成像仪 AMsR2(Advanced Microwave scanning RADIOMETER 2) WRFDA(Weather Research and Forecasting model’s Data Assimilation) 资料同化 台风
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哺乳动物细胞分泌的乙型肝炎病毒表面S+PreS1融合抗原的理化和生物学性状 被引量:8
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作者 田淑芳 宗芳 +5 位作者 陈红 王文 张陵林 王秀平 杨芙蓉 阮力 《病毒学报》 CAS CSCD 北大核心 2002年第4期312-316,共5页
研究了哺乳动物细胞(转基因GdSS1-18细胞系)分泌的乙型肝炎(乙肝)病毒表面S+PreS1融合抗原(SS1)纯品的理化及生物学性状,结果表明:经HPLC柱层析呈现一个对称峰,证明HBsAg颗粒所带电荷的均一性;SDS-PAGE出现P24及P27条带,未出现Gp30的条... 研究了哺乳动物细胞(转基因GdSS1-18细胞系)分泌的乙型肝炎(乙肝)病毒表面S+PreS1融合抗原(SS1)纯品的理化及生物学性状,结果表明:经HPLC柱层析呈现一个对称峰,证明HBsAg颗粒所带电荷的均一性;SDS-PAGE出现P24及P27条带,未出现Gp30的条带,凝胶扫描分析其各条带分别各占22 3%、77 7%、0%;West ernblot试验证实,P27和Gp30能与S及S1抗体结合,而P24条带仅能与S抗体结合,表明S、PreS1是特异性条带;N-末端的氨基酸序列与所用目的基因编码的序列相同;乙肝SS1融合抗原在4℃储存较稳定。动物实验结果表明:与单纯含S基因的参比疫苗相比,含SS1融合基因疫苗免疫Balb/c小鼠既产生S抗体,又产生S1抗体,S抗体的ED50滴度与参比疫苗相似,S1抗体产生早于S抗体。 展开更多
关键词 浦乳动物细胞 分泌 乙型肝炎病毒 表面s%PLUs%Pres1融合抗原 理化性状 生物学性状 N-末端序列 免疫原性
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电场对2E12铝合金中S相析出动力学的影响 被引量:7
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作者 周明哲 易丹青 +2 位作者 尹德艳 洪天然 黄道远 《中国有色金属学报》 EI CAS CSCD 北大核心 2010年第7期1290-1295,共6页
采用示差扫描量热法(DSC),研究2E12铝合金在190℃时效过程中施加强电场(±9kV/cm)对合金析出的动力学的影响,并探讨电场影响合金时效过程的微观机理。结果表明:时效时施加强电场促进了合金中Ⅰ型S相向Ⅱ型S相的转变,使得析出峰提前... 采用示差扫描量热法(DSC),研究2E12铝合金在190℃时效过程中施加强电场(±9kV/cm)对合金析出的动力学的影响,并探讨电场影响合金时效过程的微观机理。结果表明:时效时施加强电场促进了合金中Ⅰ型S相向Ⅱ型S相的转变,使得析出峰提前;未施加电场的合金样品具有更高的过饱和度、析出焓、析出相体积分数及析出速率;强电场作用降低合金中空位与溶质原子之间的结合能,进而降低S相析出激活能。根据DSC结果对S相析出激活能进行Kissinger方法和普适积分法计算发现,时效过程中施加电场与未施加电场相比,S相激活能分别降低7.9~12.7kJ/mol和6.8~22.6kJ/mol。 展开更多
关键词 2E12铝合金 s 电场 时效 示差扫描量热法 动力学
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利用广义S变换进行等效Q值扫描分析 被引量:17
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作者 李雪英 孙丹 +3 位作者 井涌泉 卢宝坤 杨晓龙 陈勇 《地球物理学进展》 CSCD 北大核心 2009年第5期1696-1702,共7页
本文首次给出了一种利用扫描分析技术与广义S变换时频分析工具相结合求取介质品质因子(Q值)的方法,与传统的Q值估计方法不同,该方法用一系列等效Q值对叠前衰减数据进行粘性补偿偏移,将偏移后的共反射点道集叠加,利用广义S变换求取补偿... 本文首次给出了一种利用扫描分析技术与广义S变换时频分析工具相结合求取介质品质因子(Q值)的方法,与传统的Q值估计方法不同,该方法用一系列等效Q值对叠前衰减数据进行粘性补偿偏移,将偏移后的共反射点道集叠加,利用广义S变换求取补偿后叠加道的时频谱和傅立叶峰值频率,以浅层强反射界面子波时频谱为参考,它他深度处地层子波的时频谱特征与之进行比较,当谱宽和峰值频率达到一致作为正确Q值选定标准,确立了宏观介质的等效Q值分析新方法. 展开更多
关键词 粘性介质 时间偏移 广义s变换 等效Q值 扫描分析
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双酚-S环氧树脂与间苯二胺固化反应动力学 被引量:8
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作者 李燕芳 赵洪池 +1 位作者 高俊刚 苏晓辉 《热固性树脂》 CAS CSCD 2005年第3期5-8,共4页
用示差扫描量热法(DSC)研究了双酚-S环氧树脂(BPSER)与间苯二胺固化反应的历程。实验结果表明,固化反应主要分为2个阶段,前期由化学动力学控制,服从自催化机理,实验数据利用Kamal方程处理得到2个速率常数k1、k2及2个反应级数m、n,k1、k... 用示差扫描量热法(DSC)研究了双酚-S环氧树脂(BPSER)与间苯二胺固化反应的历程。实验结果表明,固化反应主要分为2个阶段,前期由化学动力学控制,服从自催化机理,实验数据利用Kamal方程处理得到2个速率常数k1、k2及2个反应级数m、n,k1、k1值随反应温度的升高均呈增大的趋势,总反应级数m+n在2~2 5之间;反应活化能E1、E2分别为64 18kJ/mol和48 30kJ/mol。当反应程度达到60%左右后,由于交联程度增加,分子质量迅速增大,分子间扩散较慢,进入反应的第二阶段,主要由扩散作用控制固化速率。文章还讨论了该体系固化反应的分子机理,认为其经历了三分子的过渡态。 展开更多
关键词 双酚-s环氧树脂 间苯二胺 固化动力学 示差扫描量热法
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