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Sonographic Measurement of the Optic Nerve Sheath Diameter (ONSD) and Eyeball Transversal Diameter (ETD) in Benin Healthy African Adults 认领
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作者 Kofi-Mensa Savi de Tové Djivèdé Akanni +5 位作者 Miralda Kiki Sonia Adjadohoun Godfrid Lokossou Patricia Yèkpè-Ahouansou Olivier Biaou Vicentia Boco 《放射学期刊(英文)》 2020年第3期149-158,共10页
<strong>Background:</strong> Measuring optic nerve sheath diameter (ONSD), a relatively re-cent technique, allows an indirect and non-invasive diagnosis of intracranial hypertension. The ONSD ratio to eyeb... <strong>Background:</strong> Measuring optic nerve sheath diameter (ONSD), a relatively re-cent technique, allows an indirect and non-invasive diagnosis of intracranial hypertension. The ONSD ratio to eyeball transverse diameter (ETD) increases this reliability of the technique. The objective of this study was to determine the normal ONSD and its ratio with ETD in black African adults in Benin. <strong>Methods:</strong> A descriptive cross-sectional study was conducted between May 2019 and August 2019. Ultrasound ONSD and ONSD/ETD ratio were meas-ured in 210 healthy adults received in the medical imaging department of the Borgou and Alibori University Hospital Center in Benin. The ONSD corre-sponded to the average of 12 measurements (03 horizontal and 03 vertical for each eye) taken 3 mm behind the papilla. The transverse ETD corresponded to the average of 03 measurements. <strong>Results:</strong> The mean ONSD was 4.20 ± 0.28 mm (95% CI = [4.17;4.24] mm and 95th percentile = 4.70 mm). The mean ETD was 24.25 ± 1.10 mm. The ONSD/ETD ratio was 0.17 ± 0.01 (95% CI = [0.17;0.17] and 95th percentile = 0.19). There was no difference between ver-tical and horizontal ONSD and between right and left ONSD. The ONSD and the ONSD/ETD ratio were not correlated with any of the socio-demographic and anthropometric characteristics studied (sex, age, ethnicity, weight, height, body mass index, head circumference and waist circumference). The ONSD was associated with ETD (p < 0.001 and r = 0.55). <strong>Conclusion:</strong> An ONSD and an ONSD/ETD ratio respectively greater than 4.70 mm and 0.19 should sus-pect intracranial hypertension. The ONSD/ETD ratio may be a better indicator of HICT because of its small variation. 展开更多
关键词 Optic Nerve Sheath Diameter Eye Transversal Diameter Ultrasound Intracranial Hypertension Adult BENIN
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基于Diameter的可信接入网络技术设计 认领
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作者 杨帆 杨玉发 李春林 《通信技术》 2020年第10期2495-2500,共6页
基于局域网协议架构的可信网络接入认证受局域网协议的缺陷限制,如网络扩容受限、缺乏端端安全保护、不可靠UDP传输以及无失败恢复机制等问题,目前仅能在小规模局域网应用。针对局域网可信网络接入认证的缺陷和广域网可信接入认证的应... 基于局域网协议架构的可信网络接入认证受局域网协议的缺陷限制,如网络扩容受限、缺乏端端安全保护、不可靠UDP传输以及无失败恢复机制等问题,目前仅能在小规模局域网应用。针对局域网可信网络接入认证的缺陷和广域网可信接入认证的应用需求,提出了一种基于Diameter协议基础架构的可信接入认证方法,包括协议流程和网络架构设计,具备广域网部署应用、可信度量特征可细腻度粒化以及端到端安全保护等特征。 展开更多
关键词 可信网络 DIAMETER 广域网可信认证 RADIUS
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文章速递单壁碳纳米管的直径可控生长 认领
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作者 张则尧 姚艺希 李彦 《中国科学:化学》 CAS CSCD 北大核心 2020年第10期1188-1204,共17页
单壁碳纳米管具有十分独特的结构和优异的性质,在许多领域都有重要的应用前景.单壁碳纳米管的直径可控生长是碳纳米管合成中的基础问题之一.在这篇综述中,我们从催化剂的尺寸控制和生长条件的调控两个方面讨论了单壁碳纳米管直径可控生... 单壁碳纳米管具有十分独特的结构和优异的性质,在许多领域都有重要的应用前景.单壁碳纳米管的直径可控生长是碳纳米管合成中的基础问题之一.在这篇综述中,我们从催化剂的尺寸控制和生长条件的调控两个方面讨论了单壁碳纳米管直径可控生长的策略.设计合成尺寸均一的催化剂,防止催化剂的团聚和熟化,是控制催化剂尺寸的主要问题.碳源的种类与浓度、生长温度以及其他气体组分等化学气相沉积条件也会显著影响碳纳米管的直径分布.有效控制催化剂的尺寸,再结合对化学气相沉积生长条件的合理调控,才能实现单壁碳纳米管的直径可控生长. 展开更多
关键词 单壁碳纳米管 化学气相沉积 可控生长 直径
Basic Physical Properties and Degradability of Tungsten Wire Fibers 认领
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作者 朱烨佳 马颜雪 +2 位作者 关国平 孟粉叶 李毓陵 《东华大学学报:英文版》 EI CAS 2020年第1期50-54,共5页
In order to explore the feasibility of tungsten filament as biomedical metal material,this article conducted a series of performance tests on two different thicknesses of black tungsten filament and two different thic... In order to explore the feasibility of tungsten filament as biomedical metal material,this article conducted a series of performance tests on two different thicknesses of black tungsten filament and two different thicknesses of white tungsten filament.It mainly tested the basic physical properties of the tungsten filament including the longitudinal cross-section of the fiber,the fiber diameter,the mechanical properties of the fiber and the biodegradability,and analyzed the results.The results showed that the breaking force of tungsten filament was about 3000MPa.And whether it was black tungsten filament or white tungsten filament,the larger the diameter,the greater the breaking force,and the breaking strength of the tungsten filament was much larger than the breaking strength of the steel wire.The larger the diameter of the tungsten filament,the slower the degradation rate.During the two months,the mass loss rate of the thick black tungsten filament was 59.40%,thin black tungsten filament was 83.88%,thick white tungsten filament was 47.39%,thin white tungsten filament was 72.29%,the degradation rate of thick tungsten wire was nearly half of the thin,and degradation mainly occured in the first months. 展开更多
关键词 TUNGSTEN FILAMENT DEGRADATION performance MECHANICAL properties DIAMETER
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紫椴人工林直径分布规律及生长特性分析 认领
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作者 陆斐 杨世桢 +3 位作者 陈晓波 初艳 王有菊 王璧莹 《吉林林业科技》 2020年第5期4-7,共4页
对吉林市林科院松花湖紫椴人工林胸径和解析木进行了研究。结果表明:该紫椴人工林胸径分布符合正态分布和Logistic分布,胸径和树高在第3~6年为快速生长期,目前林分生长处于慢速生长期。
关键词 紫椴 人工林 直径 解析木
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浮球大小对消减水面蒸发效果敏感性试验研究 认领
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作者 候宗民 《水利科学与寒区工程》 2020年第4期9-14,共6页
为确定浮球直径大小和质量对水面抑制蒸发率的影响及确定最优值,采用控制变量法和对比法设计两组试验,利用SPSS等数据软件对试验结果进行数据分析,并建立不同试验设计与气象因素之间的联系模型。结果表明:在浮球没入水深为0到半径大小之... 为确定浮球直径大小和质量对水面抑制蒸发率的影响及确定最优值,采用控制变量法和对比法设计两组试验,利用SPSS等数据软件对试验结果进行数据分析,并建立不同试验设计与气象因素之间的联系模型。结果表明:在浮球没入水深为0到半径大小之间,浮球质量越大,抑制蒸发效果越好;浮球直径大小在55~100 mm,抑制蒸发率值越大;浮球在水面移动会破坏水面蒸发平衡,改变水面微气候,从而降低浮球的抑制蒸发效果。 展开更多
关键词 浮球 直径大小 质量 抑制蒸发率
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Left atrial diameter and atrial fibrillation,but not elevated NT-proBNP,predict the development of pulmonary hypertension in patients with HFpEF 认领
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作者 Yi-Xian LIU Hui LI +8 位作者 Yi-Yuan XIA Chun-Lei XIA Xin-Liang QU Peng CHU Wen-Yin ZHOU Lin-Lin ZHU Li LI Shao-Liang CHEN Jun-Xia ZHANG 《老年心脏病学杂志:英文版》 SCIE CAS CSCD 2020年第7期400-409,共10页
Background The determinants of pulmonary hypertension(PH)due to heart failure with preserved ejection fraction(HFpEF)have been poorly investigated in patients with cardiovascular diseases(CVD).Methods From July 12017 ... Background The determinants of pulmonary hypertension(PH)due to heart failure with preserved ejection fraction(HFpEF)have been poorly investigated in patients with cardiovascular diseases(CVD).Methods From July 12017 to March 312019,a total of 149 consecutive HFp EF patients hospitalized with CVD were enrolled in this prospective cross-sectional study.A systolic pulmonary artery pressure(PASP)>35 mm Hg estimated by echocardiography was defined as PH-HFp EF.Logistic regression was performed to establish predictors of PH in HFpEF patients.Results Overall,the mean age of participants was 72±11 years,and 74(49.7%)patients were females.A total of 59(39.6%)patients were diagnosed with PH-HFpEF by echocardiography.The left atrial diameter(LAD)was related to the ratio of the transmitral flow velocities/mitral annulus tissue velocities in early diastole(E/E’)and the left ventricular diameter in systole(LVDs).N-Terminal pro B-type natriuretic peptide(NT-proBNP)was not found to be associated with LAD and impaired diastolic or systolic function of the left ventricle.Multivariable logistic regression showed that atrial fibrillation(AF)increased the risk of PH-HFpEF incidence 3.46-fold with a 95%confidence interval(CI)of 1.44–8.32,P=0.005.Meanwhile,LAD≥45 mm resulted in a 3.43-fold increased risk,95%CI:1.51–7.75,P=0.003.However,the significance levels of NT-proBNP,age and LVEF were underpowered in the regression model.Two variables,AF and LAD≥45 mm,predicted the PH-HFpEF incidence(C-statistic=0.773,95%CI:0.695–0.852,P<0.001).Conclusions Two parameters associated with electrical and anatomical remodelling of the left atrium were related to the incidence of PH in HFpEF patients with CVD. 展开更多
关键词 Atrial fibrillation Ejection fraction Heart failure Left atrial diameter Pulmonary hypertension
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Variations in fine root dynamics and turnover rates in five forest types in northeastern China 认领
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作者 Nan Wang Chuankuan Wang Xiankui Quan 《林业研究:英文版》 SCIE CAS CSCD 2020年第3期871-884,共14页
Quantifying fi ne root(≤ 2.0 mm in diameter) distribution and turnover is essential for accurately estimating forest carbon budgets. However, fi ne root dynamics are poorly understood, possibly because of their inacc... Quantifying fi ne root(≤ 2.0 mm in diameter) distribution and turnover is essential for accurately estimating forest carbon budgets. However, fi ne root dynamics are poorly understood, possibly because of their inaccessibility. This study quantifi es fi ne root distribution and turnover rates for fi ve representative Chinese temperate forests types. Fine root number, diameter, biomass, necromass, production, mortality, and turnover rates were measured using a minirhizotron over a 12-month period. More than 90% of the fi ne roots were < 0.5 mm in diameter, with thin fi ne roots at shallow layers, and thicker ones in deeper soil layers. The fi ne root dynamics were signifi cantly diff erent among the forest types. Coniferous plantations had fewer fi ne roots, less biomass, necromass, production and mortality but greater average diameters than fi ne roots of broadleaved forests. All traits, except for diameter, decreased along the soil profi le. Fine root numbers and production exhibited a unimodal seasonal pattern with peaks occurring in summer, whereas biomass, necromass and mortality progressivelyincreased over the growing season. The turnover rates of roots < 0.5 mm varied from 0.4 to 1.0 a-1 for the fi ve forest types, 0.5–1.0 a-1 for the soil layers and 0.2–1.1 a-1 for the seasons, with the largest turnover rate at the 0–10 cm depth in summer. The patterns of fi ne root numbers, biomass, necromass, production, mortality, and turnover rates varied with forest types, soil depths, growing season and diameter classes. This study highlights the importance of forest types and diameters in quantifying fi ne root turnover rates. 展开更多
关键词 BIOMASS Necromass MORTALITY Production ROOT DIAMETER ROOT number
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法洛四联症患者左-主肺动脉夹角特点及其与肺动脉发育的关系 认领
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作者 曹嵘 陈鹏帆 +5 位作者 王越 张煜宸 易文琪 何梦婷 凌云飞 安琪 《中国胸心血管外科临床杂志》 CAS CSCD 2020年第1期26-30,共5页
目的探讨法洛四联症(tetralogy of Fallot,TOF)患者左-主肺动脉夹角特点及其与肺动脉发育的关系。方法选择四川大学华西医院心脏大血管外科2014~2018年收治的TOF患者共101例作为研究组(TOF组),其中男62例、女39例,年龄6.8(0.3~45.8)岁;... 目的探讨法洛四联症(tetralogy of Fallot,TOF)患者左-主肺动脉夹角特点及其与肺动脉发育的关系。方法选择四川大学华西医院心脏大血管外科2014~2018年收治的TOF患者共101例作为研究组(TOF组),其中男62例、女39例,年龄6.8(0.3~45.8)岁;另选取同期无心脏基础疾病的患者20例作为对照组,其中男10例、女10例,年龄6.9(0.3~54.0)岁。测量并比较两组患者的左肺动脉(left pulmonary artery,LPA)直径、右肺动脉(right pulmonary artery,RPA)直径、主肺动脉(main pulmonary artery,MPA)直径、MPA-LPA夹角、McGoon比值、Nakata指数等指标。分析以上数据与MPA-LPA夹角大小的关系。结果TOF患者MPA-LPA夹角平均值较对照组小(113.63度vs.128.45度,P=0.0018)。TOF组MPA Z值小于对照组(0.46 vs.2.75,P=0.0004)。对照组和TOF组MPA-LPA夹角与LPA Z值、MPA Z值均无统计学关系(P值分别为:对照组,0.2396、0.1147;TOF组,0.7593、0.2427)。MPA-LPA夹角大小与手术方式的选择如是否跨瓣补片无关(P=0.1600)。结论TOF患者MPA-LPA夹角及MPA直径较非TOF患者小;MPA-LPA夹角大小与肺动脉直径、手术方式的选择无关。 展开更多
关键词 法洛四联症 肺动脉 夹角 直径
混凝土中不同直径钢筋的雷达图像研究 认领
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作者 刘金龙 陆伟东 袁小军 《建筑科学》 CSCD 北大核心 2020年第7期137-141,共5页
介绍了雷达技术在混凝土结构无损检测中的应用原理,推导了不同直径钢筋的雷达成像的方程式,雷达图像具有双曲线形态的特征。通过数值模拟分析了不同直径钢筋、不同深度情况下的雷达图像的变化规律,制作了钢筋混凝土试件进行雷达图像的... 介绍了雷达技术在混凝土结构无损检测中的应用原理,推导了不同直径钢筋的雷达成像的方程式,雷达图像具有双曲线形态的特征。通过数值模拟分析了不同直径钢筋、不同深度情况下的雷达图像的变化规律,制作了钢筋混凝土试件进行雷达图像的对比试验,试验结果验证了数值模拟结果的准确性。研究成果为解决混凝土中不同直径钢筋的探测提供了数据支撑。 展开更多
关键词 雷达 雷达图像 钢筋 直径 数值模拟
棉纱表面直径数据库建立及规律研究 认领
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作者 蔡彩虹 胡海霞 +1 位作者 王金芳 张才前 《纺织科技进展》 CAS 2020年第4期17-20,共4页
探讨了棉纱线的捻度、直径与纱线支数之间的关系。选择12种不同支数的棉纱线,借助捻度仪改变各纱线捻度,获得了60种不同捻度规格的纱线,利用尼康数码显微镜测试纱线直径,建立棉纱线的直径分布数据库。结果表明:同种支数的棉纱线随着捻... 探讨了棉纱线的捻度、直径与纱线支数之间的关系。选择12种不同支数的棉纱线,借助捻度仪改变各纱线捻度,获得了60种不同捻度规格的纱线,利用尼康数码显微镜测试纱线直径,建立棉纱线的直径分布数据库。结果表明:同种支数的棉纱线随着捻度的增加,其直径呈抛物线变化曲线,先增大后减小,其中抛物线的顶点所对应的纱线捻度为纱线最大直径的临界捻度点,同时通过建立的纱线直径数据库可直观读出棉纱线的支数。 展开更多
关键词 纱线表面 捻度 直径
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On-Line Measurement Method for Diameter and Roundness Error of Balls 认领
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作者 Yindi Cai Bo Xie +1 位作者 Siying Ling Kuang-Chao Fan 《纳米制造与计量(英文)》 2020年第3期218-227,共10页
This paper presents an on-line measurement method for the diameter and roundness error of balls.An easy-installation rotary scanning system,which integrates the principles of the diameter and the roundness measurement... This paper presents an on-line measurement method for the diameter and roundness error of balls.An easy-installation rotary scanning system,which integrates the principles of the diameter and the roundness measurements,is constructed.The rotary scanning system consists of a rotary stage,a linear stage,and two sensors with a什at probe.Two sensors are initially installed on the linear stage and contact each other.The outputs of two sensors are reset to zero at first.The ball is then mounted on the rotary stage and positioned between two flat probes.The variations of the diameter and the roundness error of the ball at each angular position can be directly recorded by two sensors when the ball is rotated by the rotary stage.Substituting the outputs of two sensors into the proposed mathematical models,the diameter and roundness error can be evaluated.The effects of the alignment error induced by the spindle error of the rotary stage and the titling error and the eccentric error of the ball on the measurement accuracy can be self-separated in the proposed on-line measurement method.A series of experiments are carried out to verify the effectiveness and the capability of the proposed on-line measurement method and the designed rotary scanning system.The designed system is easy to construct both in the laboratory environment and the factory field. 展开更多
关键词 On-line measurement DIAMETER Roundness error Alignment error
Retinal vascular diameter changes assessed with a computer-assisted software after strabismus surgery 认领
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作者 Jin-Qiong Zhou Jing Fu +4 位作者 Ji-Peng Li Xiao-Zhen Wang Wen-Ying Wang Bo-Wen Zhao Meng Qi 《国际眼科杂志:英文版》 SCIE CAS 2020年第4期620-624,共5页
AIM: To quantitatively investigate the retinal vascular diameter changes, analyzing the early and long-term effects on the retinal circulation, with 6-month follow-up. METHODS: Patients underwent horizontal strabismus... AIM: To quantitatively investigate the retinal vascular diameter changes, analyzing the early and long-term effects on the retinal circulation, with 6-month follow-up. METHODS: Patients underwent horizontal strabismus surger y were enrolled prospectively. Retinal vessel diameters on color fundus photographs were assessed before and 1, 7 d, 6 mo after surgery, using a computerassisted quantitative assessment software. To evaluate the retinal vascular caliber changes, retinal vascular diameters were calculated by means of the Parr–Hubbard formula as the central retinal arteriolar equivalent(CRAE) and central retinal venular equivalent(CRVE). The arteriovenous ratio(AVR) was calculated as CRAE divided by CRVE. RESULTS: A total of 154 eyes of 104 consecutive patients were included. Compared with the data before surgery(121.55±24.67), the mean CRAE(131.18±28.29) significantly increased 1 d af ter surger y(P=0.003), but went back to baseline level at 7 d(118.89±30.35, P=0.15), and 6 mo(123.22±15.32, P=0.60), so did the AVR(P<0.001, P=0.08, P=0.07). As for the mean CRVE, there was no significant difference between those four time points(172.43±33.25, 175.57±36.98, 174.03±40.18, 174.86±20.46, P=1.00). CONCLUSION: Strabismus surgery on both lateral and media rectus muscles, or single media rectus muscle may increase retinal blood flow during the early postoperative period, but would return to normal later. The number of transected anterior ciliary arteries rather might be the main cause of retinal hemodynamic changes early after strabismus surgery. 展开更多
关键词 RETINAL BLOOD flow RETINAL VASCULAR DIAMETER STRABISMUS STRABISMUS surgery
Response of Two Unequal-Diameter Flexible Cylinders in A Side-by-Side Arrangement:Characteristics of FIV 认领
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作者 XU Wan-hai ZHANG Qian-nan +1 位作者 MA Wen-chen WANG En-hao 《中国海洋工程:英文版》 SCIE EI CSCD 2020年第4期475-487,共13页
Till now,little information is available on the flow-induced vibration(FIV)of multiple flexible cylinders with unequal diameters.Some FIV characteristics of unequal-diameter cylinders can be predicted based on the kno... Till now,little information is available on the flow-induced vibration(FIV)of multiple flexible cylinders with unequal diameters.Some FIV characteristics of unequal-diameter cylinders can be predicted based on the knowledge of equal-diameter cylinders,while there are still other features remaining unrevealed.In this paper,the FIV characteristics of two flexible cylinders with unequal diameters arranged side-by-side are experimentally investigated.The diameter ratio of the small cylinder(Small Cyl.)to the large cylinder(Large Cyl.)is nearly 0.5.The aspect ratios and mass ratios of the two flexible cylinders are 350/181 and 1.90/1.47,respectively.The centre-tocentre spacing ratio in the cross-flow(CF)direction is kept constant as 6.0 and the two cylinders can oscillate freely in both the CF and in-line(IL)directions.The towing velocity varies from 0.05 m/s to 1.00 m/s.The dominant modes and frequencies,CF and IL displacement amplitudes and response trajectories are discussed.Compared with the case of two identical cylinders in our previous study,the FIV responses demonstrate some similarities and differences.The similarities are as follows.Both cylinders exhibit multi-mode vibration features and they interact with each other.Meanwhile,the IL FIV shows a more complex behaviour than that in the CF direction.The difference is that as the diameter of one cylinder is increased,the effect on the smaller cylinder becomes more significant.For Large Cyl.,the FIV response is similar to its isolated counterpart,which indicates that Small Cyl.has a negligible effect on the FIV of the larger one.Whereas Large Cyl.perplexes the FIV of Small Cyl.during the vibration process.The spacing would change when both cylinders are oscillating.Proximity interference between the two cylinders and wake shielding effect of the Large Cyl.may occur.The dominant frequencies of Small Cyl.are reduced and the wake-induced flutter of Small Cyl.is observed from the response trajectories at different measuring points. 展开更多
关键词 flow-induced vibration(FIV) flexible cylinder side-by-side unequal diameter wake-induced flutter
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抗幽门螺旋杆菌治疗对直径小于0.5 cm胃息肉的疗效观察 认领
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作者 商西丹 赵新华 +1 位作者 敬长春 岳宗柱 《中国继续医学教育》 2020年第12期143-145,共3页
目的探讨抗幽门螺旋杆菌对直径小于0.5 cm胃息肉的治疗疗效观察。方法选取直径小于0.5 cm胃息肉患者160例,检测其幽门螺旋杆菌。抽取幽门螺旋杆菌感染阳性患者120例,随机分为治疗组60例,对照组60例。治疗组患者接受抗幽门螺旋杆菌四联治... 目的探讨抗幽门螺旋杆菌对直径小于0.5 cm胃息肉的治疗疗效观察。方法选取直径小于0.5 cm胃息肉患者160例,检测其幽门螺旋杆菌。抽取幽门螺旋杆菌感染阳性患者120例,随机分为治疗组60例,对照组60例。治疗组患者接受抗幽门螺旋杆菌四联治疗,对照组仅接受一般治疗。受试者治疗结束后6~12个月均接受定期胃镜检查和幽门螺旋杆菌的测定。结果治疗组有49例(85.96%),用药后6~12个月随访中Hp得到根除,在Hp根除者中29例(59.18%)胃息肉消失,另外20例胃息肉也有不同程度的消退。而对照组中胃息肉未发生变化(P<0.05)。结论根除幽门螺杆菌对胃息肉具有良好的治疗作用。 展开更多
关键词 幽门螺旋杆菌 直径 小于 0.5 CM 胃息肉 疗效
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Fabrication and shape detection of a catheter using fiber Bragg grating 认领
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作者 Xiang-Yan Chen Ya-Nan Zhang +2 位作者 Lin-Yong Shen Jin-Wu Qian Jia-Ying Fan 《先进制造进展:英文版》 SCIE CAS CSCD 2020年第1期107-118,共12页
Considering the spatial position and shape detection properties of the fiber Bragg grating(FBG)curve sensor used in the human body,the positioning accuracy of the FBG curve sensor plays a major role in the pre-diagnos... Considering the spatial position and shape detection properties of the fiber Bragg grating(FBG)curve sensor used in the human body,the positioning accuracy of the FBG curve sensor plays a major role in the pre-diagnosis and treatment of diseases.We present a new type of shape-sensing catheter(diameter of 2.0 mm and length of 810 mm)that is integrated with an array of four optical fibers,where each contains five nodes,to track the shape.Firstly,the distribution of the four orthogonal fiber gratings is wound around a nitinol wire using novel packaging technology,and the spatial curve shape is rebuilt based on the positioning of discrete points in space.An experimental platform is built,and then a reconstruction algorithm for coordinate point fitting of the Frenet frame is used to perform the reconstruction experiment on millimeter paper.The results show that,compared with those in previous studies,in 2D test,the maximum relative error for the end position is reduced to 2.74%,and in 3D reconstruction experiment,the maximum shape error is 3.43%,which verifies both the applicability of the sensor and the feasibility of the proposed method.The results reported here will provide an academic foundation and the key technologies required for navigation and positioning of noninvasive and minimally invasive surgical robots,intelligent structural health detection,and search and rescue operations in debris. 展开更多
关键词 Fiber Bragg grating(FBG) Thin diameter Encapsulation positioning Shape detection
沼泽湿地恢复演替过程中朝天委陵菜间隔子性状与分枝强度的关系 认领
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作者 李雪萍 赵成章 +2 位作者 任悦 张晶 雷蕾 《生态学报》 CAS CSCD 北大核心 2020年第1期123-129,共7页
间隔子和分株影响克隆植物的空间分布和资源获取,二者之间关系的研究有助于理解克隆植物的生态适应机制。按照恢复时间设置I(5a)、II(15a)、III(25a)3个梯度,研究了永昌北海子国家湿地公园沼泽湿地恢复演替过程中朝天委陵菜(Potentilla ... 间隔子和分株影响克隆植物的空间分布和资源获取,二者之间关系的研究有助于理解克隆植物的生态适应机制。按照恢复时间设置I(5a)、II(15a)、III(25a)3个梯度,研究了永昌北海子国家湿地公园沼泽湿地恢复演替过程中朝天委陵菜(Potentilla supina)间隔子长度、直径与分枝强度之间的关系。结果表明:随着沼泽湿地恢复演替的进行,湿地群落的高度、盖度和生物量逐渐增大,土壤含水量、有机质逐渐增大,土壤容重逐渐降低;湿地群落的优势植物种群由朝天委陵菜转为黑麦草;朝天委陵菜间隔子长度和直径增大,分株数减小;间隔子长度、直径与分枝强度均呈显著负相关关系(P<0.05)。沼泽湿地恢复演替过程中,朝天委陵菜由选择垄断区域资源转向逃避或忍耐不利生境,体现了湿地克隆植物在异质性生境中独特的适应性。 展开更多
关键词 恢复演替 间隔子长度 直径 分枝强度 朝天委陵菜 永昌北海子国家湿地公园
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不同直径钢筋、不同埋深的雷达图像试验研究 认领
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作者 刘金龙 陆伟东 +1 位作者 袁小军 浦琛琛 《四川建筑科学研究》 2020年第1期8-14,共7页
介绍了雷达技术的应用原理,制作了不同直径钢筋、不同埋深的混凝土试件,得到了钢筋的雷达图像典型特征,边缘检测结合腐蚀、膨胀快速提取了钢筋的边缘骨架曲线。制作了不同直径、不同埋深的6个泡沫试件,并进行了雷达图像的比对试验。试... 介绍了雷达技术的应用原理,制作了不同直径钢筋、不同埋深的混凝土试件,得到了钢筋的雷达图像典型特征,边缘检测结合腐蚀、膨胀快速提取了钢筋的边缘骨架曲线。制作了不同直径、不同埋深的6个泡沫试件,并进行了雷达图像的比对试验。试验结果表明:相同埋深、不同直径钢筋的雷达图像非常相似,所成的双曲线大小和形状很接近;相同直径钢筋、不同埋深的雷达图像均不同,埋深对钢筋所成的双曲线图像影响较大。研究成果为解决不同直径钢筋的探测提供了数据支撑。 展开更多
关键词 雷达 雷达图像 钢筋 直径 埋深 试验研究
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超临界/密相二氧化碳长输管道内径计算方法探讨 认领
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作者 闫兴清 李佳桐 +4 位作者 喻健良 曹琦 闫振汉 于帅 陈庆 《石油化工设备》 CAS 2020年第4期22-26,共5页
随着二氧化碳捕集、利用及封存技术的不断应用,二氧化碳管道的建设需求逐渐增大。确定长输管道的直径,是研究超临界/密相二氧化碳管道输运工艺及经济性的首要问题。通过理论分析,基于机械能衡算方程推导了超临界/密相二氧化碳长输管道... 随着二氧化碳捕集、利用及封存技术的不断应用,二氧化碳管道的建设需求逐渐增大。确定长输管道的直径,是研究超临界/密相二氧化碳管道输运工艺及经济性的首要问题。通过理论分析,基于机械能衡算方程推导了超临界/密相二氧化碳长输管道内径计算公式,分析了部分计算参数,如平均压力、平均温度、平均压缩因子和摩擦因数等的确定方法。将管道内径计算结果与现有文献计算结果进行了对比,验证了提出的管道内径计算公式的可靠性。 展开更多
关键词 长输管道 二氧化碳 直径 水力模型 计算
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口模直径对高密度聚乙烯薄膜性能的影响 认领
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作者 李艳芹 王金道 +1 位作者 王佳琦 樊洁 《石化技术与应用》 CAS 2020年第4期240-243,共4页
分别采用口模直径为50,75 mm的吹膜机制得高密度聚乙烯薄膜产品DN 50,DN 75,考察了口模直径对薄膜性能的影响。结果表明:DN 50薄膜的拉伸强度、横向撕裂强度、横向断裂标称值、落标冲击质量均高于DN 75薄膜;但DN 50薄膜的雾度、纵向撕... 分别采用口模直径为50,75 mm的吹膜机制得高密度聚乙烯薄膜产品DN 50,DN 75,考察了口模直径对薄膜性能的影响。结果表明:DN 50薄膜的拉伸强度、横向撕裂强度、横向断裂标称值、落标冲击质量均高于DN 75薄膜;但DN 50薄膜的雾度、纵向撕裂强度、纵向断裂标称值均低于DN 75薄膜;相同条件下制得的薄膜,随着吹胀比的增大,其雾度、横向拉伸强度、纵向撕裂强度、纵向断裂标称值增加,落标冲击质量降低;相同吹胀比下,DN 50薄膜的结晶度与DN 75相当。 展开更多
关键词 高密度聚乙烯 吹塑 薄膜 口模 直径 力学性能 光学性能
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