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1247例中枢神经系统感染性疾病的流行病学及临床特征分析 被引量:1
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作者 赵家华 岑雨樱 +11 位作者 许晓娇 杨飞 张兴文 董钊 刘若卓 黄德晖 崔荣太 王湘庆 田成林 黄旭升 于生元 张家堂 《解放军医学杂志》 CAS CSCD 北大核心 2024年第1期43-49,共7页
目的总结单中心中枢神经系统(CNS)感染性疾病的流行病学及临床特征。方法回顾性分析2001-2020年解放军总医院第一医学中心诊治的1247例CNS感染性疾病患者的病原体、性别、发病年龄与时间、受教育程度、职业分布等流行病学特点,以及临床... 目的总结单中心中枢神经系统(CNS)感染性疾病的流行病学及临床特征。方法回顾性分析2001-2020年解放军总医院第一医学中心诊治的1247例CNS感染性疾病患者的病原体、性别、发病年龄与时间、受教育程度、职业分布等流行病学特点,以及临床表现、住院天数、住院费用、宏基因组学测序的阳性率和预后等临床特征。结果1247例CNS感染性疾病患者的病原体依次为病毒743(59.6%)、结核分枝杆菌249(20.0%)、其他细菌150(12.0%)、真菌68(5.5%)、寄生虫18(1.4%)、梅毒螺旋体18(1.4%)和立克次体1(0.1%);2011-2020年的病例数较2001-2010年增加177例(33.1%,P<0.05);病原体的季节分布差异无统计学意义(P>0.05);男女比例为1.87︰1,多在60岁以下发病;病毒以学生人群易感,尤以大学(大专)及以上学历者较多;结核分枝杆菌和其他细菌感染以农民偏多,梅毒螺旋体感染多见于工人;临床表现以发热、头痛及脑膜刺激征多见,脑神经受累以展神经居多;宏基因组学第二代测序明显提高了临床诊断的精准性;患者中位住院天数为18.00(11.00,27.00)d,中位住院费用2.95(1.60,5.92)万元;疾病病死率1.6%。结论CNS感染性疾病发病率近年有升高趋势,临床表现复杂、症状重、预后差。早期精准诊断及临床规范治疗有利于降低病死率,减轻疾病负担。 展开更多
关键词 中枢神经系统 感染性疾病 流行病学 临床特征
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利拉鲁肽和达格列净治疗糖尿病肾病的疗效比较
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作者 刘艳 董昭 +1 位作者 晏玥 贾海菊 《山西大同大学学报(自然科学版)》 2024年第1期72-74,80,共4页
目的评估利拉鲁肽和达格列净治疗糖尿病肾病的疗效。方法将180例DN患者,随机分为对照组、利拉鲁肽组和达格列净组,每组60例。疗程均为3月,比较治疗前后各组患者体重指数、血红蛋白A1c(HbA1c)、血清肌酐(sCr)、尿酸(UA)、尿微量白蛋白(u... 目的评估利拉鲁肽和达格列净治疗糖尿病肾病的疗效。方法将180例DN患者,随机分为对照组、利拉鲁肽组和达格列净组,每组60例。疗程均为3月,比较治疗前后各组患者体重指数、血红蛋白A1c(HbA1c)、血清肌酐(sCr)、尿酸(UA)、尿微量白蛋白(uMA)、尿肌酐(uCr)和双侧肾功能,并观察各组的不良反应,同时测定各组患者治疗前后血清白细胞介素-6(IL-6)和肿瘤坏死因子-α(TNF-α)水平。结果治疗后:利拉鲁肽和达格列净组的体重指数、HbA1c、sCr、UA和uMA/uCr比值均低于对照组(所有P<0.05);各组患者血清白蛋白(sAlb)水平均升高,且实验组明显高于对照组(所有P<0.05);各组患者估计肾小球滤过率(eGFR)水平均升高,实验组高于对照组,但无统计学差异;除对照组体重指数外,3组其他各项代谢指标均有明显改善(所有P<0.05);各组患者血清IL-6和TNF-α水平均较低,实验组明显低于对照组(所有P<0.05)。治疗期间,各组患者均未观察到严重不良反应。结论两种药物均可以治疗糖尿病肾病,且疗效无统计学差异。 展开更多
关键词 糖尿病 肾病 利拉鲁肽 达格列净
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陕西西安阎良区及毗邻区域奶山羊传染性胸膜肺炎横断面调查和风险因素分析 被引量:1
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作者 董钊 李忠军 +9 位作者 张涛 王玉梅 陈峰 杨厚安 朱琳 张飞 尤鹏飞 崔忠华 张璞 何勇君 《中国兽医杂志》 CAS 北大核心 2024年第1期72-78,共7页
为掌握陕西省西安市阎良区及毗邻区域奶山羊传染性胸膜肺炎的流行情况,分析影响该病传播的风险因素,本调查采用二阶段概率抽样方法抽取阎良区全区以及毗邻的临潼区和高陵区的未免疫该病疫苗的血清样品,应用酶联免疫吸附试验进行传染性... 为掌握陕西省西安市阎良区及毗邻区域奶山羊传染性胸膜肺炎的流行情况,分析影响该病传播的风险因素,本调查采用二阶段概率抽样方法抽取阎良区全区以及毗邻的临潼区和高陵区的未免疫该病疫苗的血清样品,应用酶联免疫吸附试验进行传染性胸膜肺炎抗体检测。结果显示,该区域群表观流行率(HAP)为25.32%,群真实流行率(HTP)为23.41%(14.07%~32.74%);个体表观流行率(AP)为10.46%(8.81%~12.31%)。风险因素分析显示,“中大规模场点”和“病羊未采取隔离、治疗”是羊传染性胸膜肺炎传播的主要风险因素。结果表明,该区域存在一定程度的羊传染性胸膜肺炎流行,养殖场点需要对患病羊及时隔离治疗或淘汰,有条件的场点实施羊传染性胸膜肺炎检测与净化;在饲养规模上升的同时要加强生物安全管理水平,减少潜在风险因素的传播机会。 展开更多
关键词 奶山羊 传染性胸膜肺炎 风险因素 横断面调查 血清流行率
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卵圆孔未闭相关非卒中性疾病防治中国专家共识
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作者 中国人体健康科技促进会结构性心脏病专委会、中国医师协会神经内科分会 张玉顺 +4 位作者 于生元 董钊 何璐 朱航 白元 《心脏杂志》 CAS 2024年第2期125-134,共10页
随着近年来对卵圆孔未闭(PFO)研究的不断深入,PFO相关卒中的循证医学证据充分,其处理策略已得到国内外的一致认可,相继制定了PFO相关共识或指南。目前,临床上除对PFO相关卒中患者进行介入封堵PFO外,PFO合并其他疾病患者接受PFO封堵的数... 随着近年来对卵圆孔未闭(PFO)研究的不断深入,PFO相关卒中的循证医学证据充分,其处理策略已得到国内外的一致认可,相继制定了PFO相关共识或指南。目前,临床上除对PFO相关卒中患者进行介入封堵PFO外,PFO合并其他疾病患者接受PFO封堵的数量也快速增长,但PFO相关非卒中性疾病的循证医学证据尚不充分,国内外尚缺乏指导性文件。为了规范PFO介入治疗,结合国内外PFO临床应用和临床研究领域的最新进展,中国人体健康科技促进会结构性心脏病专委会和中国医师协会神经内科分会组织国内相关领域专家,经多次讨论形成了《卵圆孔未闭相关非卒中性疾病防治中国专家共识》。 展开更多
关键词 卵圆孔未闭 偏头痛 减压病 系统性栓塞 封堵
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头痛专病继续教育方法探索
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作者 何绵旺 董钊 +3 位作者 刘若卓 于生元 尹梓名 陈小燕 《中国继续医学教育》 2024年第4期177-181,共5页
目前国内头痛专病继续教育缺乏统一规范的标准方法,因此以解放军总医院神经内科目前开展的2种头痛继续教育模式(头痛学校和头痛进修教育)为例来探索头痛专病继续教育方法。头痛学校:以短期培训班形式招募培训对头痛诊疗有兴趣的医师,教... 目前国内头痛专病继续教育缺乏统一规范的标准方法,因此以解放军总医院神经内科目前开展的2种头痛继续教育模式(头痛学校和头痛进修教育)为例来探索头痛专病继续教育方法。头痛学校:以短期培训班形式招募培训对头痛诊疗有兴趣的医师,教授头痛诊疗基础知识、头痛系统性疾病管理模式(screen,migraine,aura,red flag and treatment,SMART)和计算机临床决策支持系统(computerized clinical decision support system,CDSS);头痛进修教育:以神经内科头痛病房、头痛门诊为实践基地开展为期半年到1年的头痛专病进修教育。头痛学校可在相对短的时间培训出大量头痛专病医师,部分优秀学员具备开办头痛专病门诊的资质和能力,但缺乏诊疗实践能力的培训;头痛进修教育:在培养头痛专病专家方面更有优势,但其时间、人力成本更高。头痛专病继续教育可有效促进头痛诊疗规范化、同质化,是减轻头痛专病所致负担的必要途径。不同头痛专病继续教育方法各有优缺点,在实践中可互为有效补充。 展开更多
关键词 头痛 患病率 诊断 治疗 头痛学校 进修教育
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Current status of liver transplantation for human immunodeficiency virus-infected patients in China's Mainland
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作者 Jian-Xin Tang dong zhao 《World Journal of Gastroenterology》 SCIE CAS 2024年第14期1958-1962,共5页
According to the report from the Chinese Center for Disease Control and Prevention,the prevalence of human immunodeficiency virus(HIV)infection exceeded 1.2 million individuals by the year 2022,with an annual increase... According to the report from the Chinese Center for Disease Control and Prevention,the prevalence of human immunodeficiency virus(HIV)infection exceeded 1.2 million individuals by the year 2022,with an annual increase of about 80000 cases.The overall prevalence of hepatitis B surface antigen among individuals co-infected with HIV reached 13.7%,almost twice the rate of the general population in China.In addition to the well-documented susceptibility to opportunistic infections and new malignancies,HIV infected patients frequently experience liver-related organ damage,with the liver and kidneys being the most commonly affected.This often leads to the development of end-stage liver and kidney diseases.Therefore,organ transplantation has emerged as an important part of active treatment for HIV infected patients.However,the curative effect is not satisfactory.HIV infection has been considered a contraindication for organ transplantation.Until the emergence of highly active anti-retroviral therapy in 1996,the once intractable replication of retrovirus was effectively inhibited.With prolonged survival,the failure of important organs has become the main cause of death among HIV patients.Therefore,transplant centers worldwide have resu-med exploration of organ transplantation for HIV-infected individuals and reached a positive conclusion.This study provides an overview of the current landscape of HIV-positive patients receiving liver transplantation(LT)in main-land China.To date,our transplant center has conducted LT for eight end-stage liver disease patients co-infected with HIV,and all but one,who died two months postoperatively due to sepsis and progressive multi-organ failure,have survived.Comparative analysis with hepatitis B virus-infected patients during the same period revealed no statistically significant differences in acute rejection reactions,cytomegalovirus infection,bacteremia,pulmonary infections,acute kidney injury,new-onset cancers,or vascular and biliary complications. 展开更多
关键词 Liver transplantation Human immunodeficiency virus INFECTION Hepatitis B virus End-stage liver disease China'Mainland
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Design and performance evaluation of a large field-of-view dual-particle time-encoded imager based on a depth-of-interaction detector
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作者 dong zhao Xu-Wen Liang +6 位作者 Ping-Kun Cai Wei Cheng Wen-Bao Jia Da-Qian Hei Qing Shan Yong-Sheng Ling Chao Shi 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第4期1-14,共14页
Time-encoded imaging is useful for identifying potential special nuclear materials and other radioactive sources at a distance.In this study,a large field-of-view time-encoded imager was developed for gamma-ray and ne... Time-encoded imaging is useful for identifying potential special nuclear materials and other radioactive sources at a distance.In this study,a large field-of-view time-encoded imager was developed for gamma-ray and neutron source hotspot imaging based on a depth-of-interaction(DOI)detector.The imager primarily consists of a DOI detector system and a rotary dual-layer cylindrical coded mask.An EJ276 plastic scintillator coupled with two SiPMs was designed as the DOI detector to increase the field of view and improve the imager performance.The difference in signal time at both ends and the log of the signal amplitude ratio were used to calculate the interaction position resolution.The position resolution of the DOI detector was calibrated using a collimated Cs-137 source,and the full width at half maximum of the reconstruction position of the Gaussian fitting curve was approximately 4.4 cm.The DOI detector can be arbitrarily divided into several units to independently reconstruct the source distribution images.The unit length was optimized via Am-Be source-location experiments.A multidetector filtering method is proposed for image denoising.This method can effectively reduce image noise caused by poor DOI detector position resolution.The vertical field of view of the imager was(-55°,55°)when the detector was placed in the center of the coded mask.A DT neutron source at 20 m standoff could be located within 2400 s with an angular resolution of 3.5°. 展开更多
关键词 Time-encoded imager Depth-of-interaction detector Dual-particle imaging Hotspot imaging
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Simplified prediction models for acoustic installation effects of train-mounted equipment
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作者 David Thompson dong zhao Giacomo Squicciarini 《Railway Engineering Science》 EI 2024年第2期125-143,共19页
Acoustic models of railway vehicles in standstill and pass-by conditions can be used as part of a virtual certification process for new trains.For each piece of auxiliary equipment,the sound power measured on a test b... Acoustic models of railway vehicles in standstill and pass-by conditions can be used as part of a virtual certification process for new trains.For each piece of auxiliary equipment,the sound power measured on a test bench is combined with meas-ured or predicted transfer functions.It is important,however,to allow for installation effects due to shielding by fairings or the train body.In the current work,fast-running analytical models are developed to determine these installation effects.The model for roof-mounted sources takes account of diffraction at the corner of the train body or fairing,using a barrier model.For equipment mounted under the train,the acoustic propagation from the sides of the source is based on free-field Green’s functions.The bottom surfaces are assumed to radiate initially into a cavity under the train,which is modelled with a simple diffuse field approach.The sound emitted from the gaps at the side of the cavity is then assumed to propagate to the receivers according to free-field Green’s functions.Results show good agreement with a 2.5D boundary element model and with measurements.Modelling uncertainty and parametric uncertainty are evaluated.The largest variability occurs due to the height and impedance of the ground,especially for a low receiver.This leads to standard deviations of up to 4 dB at low frequencies.For the roof-mounted sources,uncertainty over the location of the corner used in the equivalent barrier model can also lead to large standard deviations. 展开更多
关键词 Train noise Auxiliary equipment Acoustic installation effects Virtual certification UNCERTAINTY
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滨海高速公路改扩建温拌沥青混合料综合性能评价
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作者 周昆 徐书东 +4 位作者 徐庆超 董昭 王圣洁 柳久伟 王昱 《森林工程》 北大核心 2024年第2期208-216,共9页
评价不同温拌剂对沥青混合料性能影响规律,为工程应用中温拌剂的选择提供技术依据。分别选取Sasobit、Aspha-min、Evotherm 3种温拌剂制备温拌沥青混合料,基于车辙、低温弯曲、冻融劈裂、汉堡轮辙和动态模量试验,分析3种温拌剂对沥青混... 评价不同温拌剂对沥青混合料性能影响规律,为工程应用中温拌剂的选择提供技术依据。分别选取Sasobit、Aspha-min、Evotherm 3种温拌剂制备温拌沥青混合料,基于车辙、低温弯曲、冻融劈裂、汉堡轮辙和动态模量试验,分析3种温拌剂对沥青混合料路用性能和动态模量的综合影响。研究表明,Evotherm温拌剂对混合料的降温效果最佳,Aspha-min温拌剂与Sasobit温拌剂对沥青混合料的降温效果相当;Sasobit温拌剂能够提高混合料的高温性能,Evotherm温拌剂能够提高混合料的水稳定性,Aspha-min温拌剂的水热性能较差;中温条件下添加Evotherm温拌剂混合料模量最高,高温条件下添加Sasobit温拌剂混合料模量最高;构建混合料动态模量主曲线,Sasobit和Evotherm温拌剂均能够改善混合料的高温性能,Sasobit温拌剂造成混合料低温性能降低,Evotherm和Aspha-min温拌剂对混合料的低温不产生影响。 展开更多
关键词 道路工程 沥青混合料 温拌剂 降温效果 路用性能 动态模量
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The influence of reflections from the train body and the ground on the sound radiation from a railway rail
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作者 David J.Thompson dong zhao +3 位作者 Evangelos Ntotsios Giacomo Squicciarini Ester Cierco Erwin Jansen 《Railway Sciences》 2024年第1期1-17,共17页
Purpose – The vibration of the rails is a significant source of railway rolling noise, often forming the dominantcomponent of noise in the important frequency region between 400 and 2000 Hz. The purpose of the paper ... Purpose – The vibration of the rails is a significant source of railway rolling noise, often forming the dominantcomponent of noise in the important frequency region between 400 and 2000 Hz. The purpose of the paper is toinvestigate the influence of the ground profile and the presence of the train body on the sound radiation fromthe rail.Design/methodology/approach – Two-dimensional boundary element calculations are used, in which therail vibration is the source. The ground profile and various different shapes of train body are introduced in themodel, and results are observed in terms of sound power and sound pressure. Comparisons are also made withvibro-acoustic measurements performed with and without a train present.Findings – The sound radiated by the rail in the absence of the train body is strongly attenuated by shieldingdue to the ballast shoulder. When the train body is present, the sound from the vertical rail motion is reflectedback down toward the track where it is partly absorbed by the ballast. Nevertheless, the sound pressure at thetrackside is increased by typically 0–5 dB. For the lateral vibration of the rail, the effects are much smaller. Oncethe sound power is known, the sound pressure with the train present can be approximated reasonably well withsimple line source directivities.Originality/value – Numerical models used to predict the sound radiation from railway rails have generallyneglected the influence of the ground profile and reflections from the underside of the train body on the soundpower and directivity of the rail. These effects are studied in a systematic way including comparisons with measurements. 展开更多
关键词 Rolling noise Sound radiation Railway track Boundary elements Ground reflections DIRECTIVITY
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Prognostic value of ultrasound in early arterial complications post liver transplant
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作者 Ning-Bo zhao Yi Chen +2 位作者 Rui Xia Jian-Bo Tang dong zhao 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第1期13-20,共8页
Liver transplantation is the primary therapeutic intervention for end-stage liver disease.However,vascular complications,particularly those involving the hepatic artery,pose significant risks to patients.The clinical ... Liver transplantation is the primary therapeutic intervention for end-stage liver disease.However,vascular complications,particularly those involving the hepatic artery,pose significant risks to patients.The clinical manifestations associated with early arterial complications following liver transplantation are often non-specific.Without timely intervention,these complications can result in graft fai-lure or patient mortality.Therefore,early diagnosis and the formulation of an op-timal treatment plan are imperative.Ultrasound examination remains the pre-dominant imaging modality for detecting complications post liver transplan-tation.This article comprehensively reviews common causes and clinical present-ations of early hepatic artery complications in the post-transplantation period and delineates abnormal sonographic findings for accurate diagnosis of these con-ditions.Overall,ultrasound offers the advantages of convenience,safety,effect-iveness,and non-invasiveness.It enables real-time,dynamic,and precise evalua-tion,making it the preferred diagnostic method for post-liver transplantation assessments.INTRODUCTION Liver transplantation stands as the primary therapeutic approach for end-stage liver disease.Continuous advancements in surgical techniques and the application of novel immunosuppressive agents contribute to ongoing improvements in the success rate and overall survival in patients undergoing liver transplantation procedures.Despite these advan-cements,vascular complications,particularly those involving the hepatic artery,pose significant risks to patients.During the early stages following liver transplantation(within the first 30 d),proper hepatic artery function is crucial for hepatic arterial blood flow.During later stages,collateral circulation,including arteries such as the phrenic artery,right gastric artery,and gastroduodenal artery,becomes important for maintaining hepatic blood supply.It is now understood that the establishment of effective collateral circulation is pivotal for determining the prognosis of hepatic artery complic-ations.The clinical manifestations of these complications are closely linked to factors such as timing,severity,and the specific type of onset.Insufficient hepatic arterial blood flow can lead to abnormal liver function,hepatic infarction,and the formation of hepatic abscesses.Additionally,since the hepatic artery is the sole blood supply to the biliary tract,hepatic artery-related ischemia may result in biliary stricture,obstruction,and the formation of bile ducts.Ultrasound examination remains the primary imaging modality for diagnosing complications post liver transplantation.This article comprehensively reviews common causes and clinical presentations of early hepatic artery complications in the post-transplantation period and outlines abnormal sonographic findings for accurately diagnosing these conditions.NORMAL HEPATIC ARTERY During the intraoperative phase,an ultrasound examination is typically conducted to evaluate the hepatic artery anas-tomosis.The normal internal diameter of the hepatic artery typically ranges from 2 to 5 mm.Two strong echo points are typically identified near the anastomosis.To assess blood flow dynamics,peak systolic velocity,end-diastolic velocity,and resistance index are measured at the donor and recipient sides of the anastomosis following angle correction.Anastomotic stenosis presence and severity can be evaluated by comparing the velocity at the anastomotic site with that at the recipient side.Postoperatively,direct visualization of the anastomosis site through gray ultrasound scans is often challenging.The surgical approach has a significant impact on the proper hepatic artery’s position,resulting in a lower overall success rate of continuous visualization.Color Doppler ultrasound is primarily employed to trace the artery’s path,and spectral measurements are taken at the brightest position of the Color Doppler blood flow signal,primarily used to identify the presence of high-speed turbulence.Hepatic artery spectrum examination plays a crucial role,as a favorable arterial spectral waveform and appropriate hepatic artery flow velocity typically indicate a successful anastomosis,even in cases where the hepatic artery anastomosis cannot be directly visualized by ultrasound.The hepatic artery runs alongside the portal vein,often selected as a reference due to its larger inner diameter.A normal hepatic artery spectrum displays a regular pulsation pattern with a rapid rise in systole and a slow decline in diastole.Parameters for assessing hepatic artery resistance include a resistance index between 0.5 to 0.8 and an artery systolic acceleration of less than 80 ms.Instantaneous increases in the resistance index(RI>0.8)often occur within 2 d after surgery,followed by a subsequent return to normal hepatic arterial parameters.It has been established that the maximum blood flow velocity during systole in the hepatic artery should not exceed 200 cm/s[1]. 展开更多
关键词 Liver transplantation Vascular complication Arterial complication ULTRASOUND
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均质非饱和边坡降雨入渗解析解及在黄土边坡的应用 被引量:2
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作者 韩佳明 董照 +2 位作者 苏三庆 马鑫 李冠兵 《岩土力学》 EI CAS CSCD 北大核心 2023年第1期241-250,共10页
降雨诱发的黄土边坡失稳非常普遍。建立黄土边坡渗流场计算模型,基于非饱和土渗流控制方程。采用VG函数和Gardner函数分别描述土-水特征曲线和渗透系数曲线,利用行波约化和级数展开法推导降雨入渗解析解。利用数值反演法将模型试验数据... 降雨诱发的黄土边坡失稳非常普遍。建立黄土边坡渗流场计算模型,基于非饱和土渗流控制方程。采用VG函数和Gardner函数分别描述土-水特征曲线和渗透系数曲线,利用行波约化和级数展开法推导降雨入渗解析解。利用数值反演法将模型试验数据对土-水参数拟合,证明了该解析解的有效性。对比分析试验值与解析解在不同工况下体积含水率分布规律,分析结果表明:边坡试验模型中的浅层测点体积含水率试验值与解析解较为接近,试验值在浸润锋下移的过程中所达到的体积含水率峰值相比解析解较小;边坡试验模型中的深层测点体积含水率试验值与解析解在前期存在一定误差,深层测点体积含水率解析解在初期增长速度相较于试验值较快,主要原因是较深土层浸润锋的滞后性。 展开更多
关键词 黄土边坡 降雨入渗 行波约化 级数展开法 解析解 数值反演
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4BZ-800型荸荠收获机设计与试验 被引量:2
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作者 张国忠 董昭 +4 位作者 陈立明 刘浩蓬 张妮 陈龙 张清洪 《华中农业大学学报》 CAS CSCD 北大核心 2023年第1期219-226,共8页
针对荸荠(Eleocharis dulcis)收获劳动强度大和可应用于实际生产的收获机具匮乏的问题,结合荸荠种植田土壤条件和现有人工收获方式,设计了一种应用于带水收获的自走式荸荠收获机。该机由行走系统、传动系统、旋转扰动装置、提升分离装... 针对荸荠(Eleocharis dulcis)收获劳动强度大和可应用于实际生产的收获机具匮乏的问题,结合荸荠种植田土壤条件和现有人工收获方式,设计了一种应用于带水收获的自走式荸荠收获机。该机由行走系统、传动系统、旋转扰动装置、提升分离装置、收集装置等组成,整机传动系统分为液压传动部分和机械传动部分,液压传动部分为收获机行走系统和挖掘收获装置提供动力,可实现机具行走速度控制、挖掘收获装置高度调节、旋转扰动装置转速控制、提升分离装置转速控制,机械传动部分可为各级旋转扰动辊及提升分离装置间提供稳定的转速差,保障收获过程顺利进行。三级旋转扰动辊构成旋转扰动装置,实现对土壤和水分的充分扰动混合;齿形挖掘铲和升运链构成提升分离装置,完成荸荠果实的挖掘、果土分离、升运工作。田间试验结果显示,该机可一次性完成荸荠的挖掘、果土分离、升运、收集等工作,试验条件下该型荸荠收获机田间道路最大行驶速度为0.97m/s,田间差速转向最小转向半径为2.1 m,原地转向半径为1.3 m,最大爬坡角度为24.2°,果实挖净率为53.19%,损伤率4.21%。 展开更多
关键词 荸荠 机械收获 自走式 液压驱动 水生蔬菜 水田
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一种管道水培叶菜变方位包络定心抓取方式 被引量:1
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作者 甄文斌 冯俊杰 +4 位作者 董朝 李刘全 何梓源 邓楚恒 夏红梅 《农业工程学报》 EI CAS CSCD 北大核心 2023年第20期46-54,共9页
将不同位姿的水培叶菜包络定心夹持到种植孔中心取出,是实现茎秆精准根切,避免根部残留在管道内的关键。针对定方位抓取方式在一些方位上对叶菜向心包络扶起作用小,抓取成功率低的问题,该研究提出一种在夹持过程中使夹手相对种植孔中心... 将不同位姿的水培叶菜包络定心夹持到种植孔中心取出,是实现茎秆精准根切,避免根部残留在管道内的关键。针对定方位抓取方式在一些方位上对叶菜向心包络扶起作用小,抓取成功率低的问题,该研究提出一种在夹持过程中使夹手相对种植孔中心转动的变方位抓取方式。以水培绿宝芥蓝为抓取对象,建立夹手张开伸入、绕种植孔中心转动及闭合夹紧时的尺寸参数关系模型;构建包络定心夹持多刚体动力学仿真模型,对初始倾角为50°、65°和80°,相对种植孔边缘周向均布的8个方位P_(1)~P_(8)上的芥蓝进行包络夹持过程仿真分析;搭建抓取试验平台,对初始倾角为45°~60°、>60°~75°和>75°~90°,方位为P_(1)~P_(8)的芥蓝进行抓取试验。分析确定两手指初始张开角为15°,闭合夹角为30°,夹手变方位转动角为45°,夹手转动速度为两手指转动速度的2倍。仿真获得的变方位夹持倾角为82.18°~88.96°,定方位夹持倾角80.32°~88.57°;抓取试验获得的变方位抓持倾角为82.83°~89.65°,定方位抓持倾角70.70°~89.27°,仿真与试验结果具有较好一致性,且变方位夹持倾角定方位夹持倾角更接近90°,表明变方位夹持不同位姿芥蓝的向心包络扶起作用效果更好。3种初始倾角的变方位抓取试验获得的成功率均值分别为91.67%、95.83%和100.00%,定方位抓取成功率均值分别为87.50%、91.67%和100.00%,表明初始倾角越大抓取机构可获得的抓取成功率越高,变方位抓取初始倾角小的芥蓝可获得更高的成功率;不计P2方位双层手指伸入碰倒芥蓝样本,变方位抓取获得的最小抓取成功率均值为91.70%,相比定方位在P_(1)~P_(8)方位上均具有更好的包络定心抓取效果。研究可为管道水培叶菜采收装备的研制提供依据。 展开更多
关键词 蔬菜 采收 仿真模型 管道水培叶菜 变方位抓取方式
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犬急性胰腺炎的诊断与治疗
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作者 王珊 高娟 +1 位作者 董钊 张翊华 《动物医学进展》 北大核心 2023年第5期138-142,共5页
为进一步明确犬急性胰腺炎的病史、临床症状及治疗方法等,分析了近2年来就诊于我院的10例犬急性胰腺炎病例,发现犬急性胰腺炎的发生与犬种类、犬年龄无明显相关性,与犬长期食用高脂肉类、受外界刺激应激有关,患犬均出现呕吐的症状,患犬(... 为进一步明确犬急性胰腺炎的病史、临床症状及治疗方法等,分析了近2年来就诊于我院的10例犬急性胰腺炎病例,发现犬急性胰腺炎的发生与犬种类、犬年龄无明显相关性,与犬长期食用高脂肉类、受外界刺激应激有关,患犬均出现呕吐的症状,患犬(90%,9/10)淀粉酶超标,经过止吐、补液、补钾等治疗后,有80%(8/10)的病例康复,预后良好。通过对以上病例的分析,对犬急性胰腺炎的诊疗提供一定的参考。 展开更多
关键词 犬急性胰腺炎 诊断 治疗
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改性多壁碳纳米管导电剂对锂电池正极性能影响 被引量:2
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作者 董昭 姜楠 +3 位作者 张成斌 张新庄 窦倩 李龙 《油气与新能源》 2023年第4期95-102,共8页
实验室合成的多壁碳纳米管,经酸洗化学改性后可作锂离子电池导电剂,用于制备正极极片并组装扣式半电池。通过扫描电子显微镜观察导电剂改性后在正极浆料中的分散情况,通过红外能谱判断官能团嫁接效果,利用四探针电导率测试仪、电化学工... 实验室合成的多壁碳纳米管,经酸洗化学改性后可作锂离子电池导电剂,用于制备正极极片并组装扣式半电池。通过扫描电子显微镜观察导电剂改性后在正极浆料中的分散情况,通过红外能谱判断官能团嫁接效果,利用四探针电导率测试仪、电化学工作站及充放电循环平台测试电池正极的电化学性能。结果表明:多壁碳纳米管在化学改性后能均匀分散在正极浆料中,较改性前锂电池正极片电导率提升率约为486.30%,内部电阻值下降率约为88.96%;扣式半电池电荷转移阻抗下降率约为89.00%,电池放电容量高、循环稳定性高、波动小。经化学改性的多壁碳纳米管导电剂相较于传统导电剂具有更优异的电化学性能,导电剂纯度较高且不易团聚,在表面官能团的作用下与活性物质颗粒间有良好的界面结合力,从活性物质颗粒到导电剂再到集流体之间形成了多条电子通道,从而提升了锂离子电池正极电化学性能。 展开更多
关键词 多壁碳纳米管 酸洗化学改性 导电剂 锂离子电池正极 电化学性能
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药物过度使用性头痛复发的关联因素分析
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作者 赵魏 刘欢贤 +8 位作者 张美辰 孙姝娉 李珂 龚子骅 林晓雪 刘颖元 张淑华 董钊 于生元 《解放军医学院学报》 CAS 北大核心 2023年第7期739-743,816,共6页
背景 药物过度使用性头痛(medication overuse headache,MOH)的发生率和复发率高,造成了较大的经济和社会负担,目前缺少其复发因素的大样本研究。目的 探索与MOH复发相关的危险因素。方法 收集2015年9月-2022年1月就诊于解放军总医院第... 背景 药物过度使用性头痛(medication overuse headache,MOH)的发生率和复发率高,造成了较大的经济和社会负担,目前缺少其复发因素的大样本研究。目的 探索与MOH复发相关的危险因素。方法 收集2015年9月-2022年1月就诊于解放军总医院第一医学中心的MOH患者386例,并随访至少1年,使用非条件Logistic回归分析探索MOH复发相关的独立危险因素。结果 386例患者中,男性80例,女性306例,其中101例(26.2%)患者复发。与未复发组相比,复发组受教育程度更低(P=0.001),体质量指数更大(P=0.001),原发性头痛病程更长(P=0.048),头痛频率更高(P=0.001),头痛部位为双侧者占比更高(P<0.001),药物过度使用的病程更长(P=0.004),服用镇痛药的频率更高(P<0.001),预防治疗时间更短(P<0.001),合并焦虑(P=0.037)和睡眠障碍(P=0.024)的比例更高,差异均有统计学意义。多元Logistic回归结果显示,受教育年限≤9年(OR=2.52,95%CI:1.24~5.16,P=0.011),药物过度使用的病程长(OR=1.09, 95%CI:1.00~1.18,P=0.043)及预防治疗时间<12个月(OR=6.84,95%CI:3.82~12.22,P<0.001)与MOH复发独立关联。结论 受教育程度低、药物过度使用的病程长和针对原发性头痛的预防治疗时间短可能是MOH复发的危险因素。 展开更多
关键词 药物过度使用性头痛 复发 危险因素 镇痛药 原发性头痛
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水下采油树S密封结构优化与试验研究
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作者 张崇 余意 +3 位作者 黄亮 董钊 张红 冯定 《石油机械》 北大核心 2023年第1期70-77,共8页
S密封作为水下采油树的非金属密封圈,是水下安全生产的关键部件之一。以S密封为研究对象,进行了结构和密封机理的研究并对其结构参数进行优化。通过建立有限元仿真模型,研究了密封圈截面长度、截面宽度、弹簧直径及圆弧半径等参数对密... S密封作为水下采油树的非金属密封圈,是水下安全生产的关键部件之一。以S密封为研究对象,进行了结构和密封机理的研究并对其结构参数进行优化。通过建立有限元仿真模型,研究了密封圈截面长度、截面宽度、弹簧直径及圆弧半径等参数对密封圈性能的影响规律,并根据影响显著性采用响应面法对密封圈的关键结构参数进行优化分析,以最小等效应力与最大接触应力为目标,对密封圈结构参数进行优化。将优化后的S密封与优化前进行对比,结果得出在安全性能和密封性能上S密封均有显著的提升;最后通过静压试验对S密封进行了密封性能测试,试验结果表明S密封满足密封性能要求。研究方法和结果可为S密封以及其他类似结构密封圈的结构优化提供理论依据及数据参考。 展开更多
关键词 水下采油树 S密封 密封性能 响应面分析 结构优化 试验研究
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Outcomes of ABO-incompatible liver transplantation in end-stage liver disease patients co-infected with hepatitis B and human immunodeficiency virus 被引量:1
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作者 Jian-Xin Tang Kang-Jun Zhang +7 位作者 Tai-Shi Fang Rui-Hui Weng Zi-Ming Liang Xu Yan Xin Jin Lin-Jie Xie Xin-Chen Zeng dong zhao 《World Journal of Gastroenterology》 SCIE CAS 2023年第11期1745-1756,共12页
BACKGROUND Human immunodeficiency virus(HIV)-positive patients coinfected with hepatitis B virus(HBV)are eligible for liver transplantation(LT)in Africa and Southeast Asia,particularly China.However,the outcome of HIV... BACKGROUND Human immunodeficiency virus(HIV)-positive patients coinfected with hepatitis B virus(HBV)are eligible for liver transplantation(LT)in Africa and Southeast Asia,particularly China.However,the outcome of HIV-HBV coinfected patients referred for ABO-incompatible LT(ABOi-LT)is unknown.AIM To clarify the outcome of ABOi-LT for HIV-HBV coinfected patients with endstage liver disease(ESLD).METHODS We report on two Chinese HIV-HBV coinfected patients with ESLD who underwent A to O brain-dead donor LT and reviewed the literature on HIV-HBV coinfected patients treated with ABO-compatible LT.The pretransplantation HIV viral load was undetectable,with no active opportunistic infections.Induction therapy consisted of two sessions of plasmapheresis and a single dose of rituximab in two split doses,followed by an intraoperative regimen of intravenous immunoglobulin,methylprednisolone,and basiliximab.Post-transplant maintenance immunosuppressive agents consisted of tacrolimus and mycophenolate mofetil,and prednisone.RESULTS At the intermediate-term follow-up,patients showed undetectable HIV viral load,CD4(+)T cell counts greater than 150 cells/μL,no HBV recurrence,and stable liver function.A liver allograft biopsy showed no evidence of acute cellular rejection.Both patients survived at 36-42 mo of follow-up.CONCLUSION This is the first report of ABOi-LT in HIV-HBV recipients with good intermediate-term outcomes,suggesting that ABOi-LT may be feasible and safe for HIV-HBV coinfected patients with ESLD. 展开更多
关键词 ABO incompatibility liver transplantation Human immunodeficiency virus Hepatitis B virus End-stage liver disease IMMUNOSUPPRESSION
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基于复合神经网络提升亚米级卫星影像质量
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作者 胡争胜 董昭 +5 位作者 王华英 苏欣宇 张小磊 李佩 苏群 王涛 《航天返回与遥感》 CSCD 北大核心 2023年第4期69-78,共10页
低能见度情况下,大气粒子对太阳辐射的散射和吸收效应,降低了卫星影像像质和空间分辨率,传统图像处理方法和现在普遍应用的深度学习算法无法同时提升图像像质和空间分辨率。为了改变该现状,文章提出了基于网格去雾网络(GridDehazeNet)... 低能见度情况下,大气粒子对太阳辐射的散射和吸收效应,降低了卫星影像像质和空间分辨率,传统图像处理方法和现在普遍应用的深度学习算法无法同时提升图像像质和空间分辨率。为了改变该现状,文章提出了基于网格去雾网络(GridDehazeNet)和真实超分辨率生成对抗网络(Real-ESRGAN)组合的复合神经网络。首先采用GridDehazeNet卷积神经网络架构提升卫星影像的清晰度和对比度,再利用Real-ESRGAN增强型超分辨率生成对抗网络以提升卫星影像空间分辨率;最后利用Worldview-3多光谱图像对不同算法进行了测试,并对比不同算法的测试效果。结果表明:该复合神经网络在改善图像像质和分辨率方面效果显著,其中清晰度提高了39.11倍,对比度提高了3倍,信息熵值提高了34%;且同时避免了传统算法所带来过度增强和噪声问题,对小目标物的识别和解译的准确率有显著提高。 展开更多
关键词 卫星遥感影像 图像像质 图像增强 深度学习 超分算法 遥感应用
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