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Glucagon-like peptide-1 receptor agonists as a possible intervention to delay the onset of type 1 diabetes:A new horizon 被引量:1
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作者 Mahmoud Nassar Ajay Chaudhuri +1 位作者 Husam Ghanim Paresh Dandona 《World Journal of Diabetes》 SCIE 2024年第2期133-136,共4页
Type 1 diabetes(T1D)is a chronic autoimmune condition that destroys insulinproducing beta cells in the pancreas,leading to insulin deficiency and hyperglycemia.The management of T1D primarily focuses on exogenous insu... Type 1 diabetes(T1D)is a chronic autoimmune condition that destroys insulinproducing beta cells in the pancreas,leading to insulin deficiency and hyperglycemia.The management of T1D primarily focuses on exogenous insulin replacement to control blood glucose levels.However,this approach does not address the underlying autoimmune process or prevent the progressive loss of beta cells.Recent research has explored the potential of glucagon-like peptide-1 receptor agonists(GLP-1RAs)as a novel intervention to modify the disease course and delay the onset of T1D.GLP-1RAs are medications initially developed for treating type 2 diabetes.They exert their effects by enhancing glucose-dependent insulin secretion,suppressing glucagon secretion,and slowing gastric emptying.Emerging evidence suggests that GLP-1RAs may also benefit the treatment of newly diagnosed patients with T1D.This article aims to highlight the potential of GLP-1RAs as an intervention to delay the onset of T1D,possibly through their potential immunomodulatory and anti-inflammatory effects and preservation of beta-cells.This article aims to explore the potential of shifting the paradigm of T1D management from reactive insulin replacement to proactive disease modification,which should open new avenues for preventing and treating T1D,improving the quality of life and long-term outcomes for individuals at risk of T1D. 展开更多
关键词 Type 1 diabetes Semaglutide Glucagon-like peptide-1 receptor agonists Insulin therapy Autoimmune response Blood glucose monitoring Β-cell preservation Early screening Teplizumab Randomized controlled trials
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Nonlinear Violence in Nonlinear Oscillations at High Energy
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作者 Yair Zarmi 《Applied Mathematics》 2024年第1期65-95,共31页
This paper focuses on the characteristics of solutions of nonlinear oscillatory systems in the limit of very high oscillation energy, E;specifically, systems, in which the nonlinear driving force grows with energy muc... This paper focuses on the characteristics of solutions of nonlinear oscillatory systems in the limit of very high oscillation energy, E;specifically, systems, in which the nonlinear driving force grows with energy much faster for x(t) close to the turning point, a(E), than at any position, x(t), that is not too close to a(E). This behavior dominates important aspects of the solutions. It will be called “nonlinear violence”. In the vicinity of a turning point, the solution of a nonlinear oscillatory systems that is affected by nonlinear violence exhibits the characteristics of boundary-layer behavior (independently of whether the equation of motion of the system can or cannot be cast in the traditional form of a boundary-layer problem.): close to a(E), x(t) varies very rapidly over a short time interval (which vanishes for E → ∞). In traditional boundary layer systems this would be called the “inner” solution. Outside this interval, x(t) soon evolves into a moderate profile (e.g. linear in time, or constant)—the “outer” solution. In (1 + 1)-dimensional nonlinear energy-conserving oscillators, if the solution is reflection-invariant, nonlinear violence determines the characteristics of the whole solution. For large families of nonlinear oscillatory systems, as E → ∞, the solutions for x(t) tend to common, indistinguishable profiles, such as periodic saw-tooth profiles or step-functions. If such profiles are observed experimentally in high-energy oscillations, it may be difficult to decipher the dynamical equations that govern the motion. The solution of motion in a central field with a non-zero angular momentum exhibits extremely fast rotation around a turning point that is affected by nonlinear violence. This provides an example for the possibility of interesting phenomena in (1 + 2)-dimensional oscillatory systems. 展开更多
关键词 High-Energy Oscillations Nonlinear Violence Boundary-Layer Characteristics
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Theoretical and experimental investigations on an X-shaped vibration isolator with active controlled variable stiffness
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作者 Zeyu CHAI J.T.HAN +3 位作者 Xuyuan SONG Jian ZANG Yewei ZHANG Zhen ZHANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第8期1371-1386,共16页
A novel X-shaped variable stiffness vibration isolator(X-VSVI)is proposed.The Runge-Kutta method,harmonic balance method,and wavelet transform spectra are introduced to evaluate the performance of the X-VSVI under var... A novel X-shaped variable stiffness vibration isolator(X-VSVI)is proposed.The Runge-Kutta method,harmonic balance method,and wavelet transform spectra are introduced to evaluate the performance of the X-VSVI under various excitations.The layer number,the installation angle of the X-shaped structure,the stiffness,and the active control parameters are systematically analyzed.In addition,a prototype of the X-VSVI is manufactured,and vibration tests are carried out.The results show that the proposed X-VSVI has a superior adaptability to that of a traditional X-shaped mechanism,and shows excellent vibration isolation performance in response to different amplitudes and forms of excitations.Moreover,the vibration isolation efficiency of the device can be improved by appropriate adjustment of parameters. 展开更多
关键词 bionic vibration isolation X-shaped structure variable stiffness structure nonlinear dynamics prototype experiment
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Long-term impact of artificial intelligence on colorectal adenoma detection in high-risk colonoscopy
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作者 Kenneth W Chow Matthew T Bell +6 位作者 Nicholas Cumpian Maryanne Amour Ryan H Hsu Viktor E Eysselein Neetika Srivastava Michael W Fleischman Sofiya Reicher 《World Journal of Gastrointestinal Endoscopy》 2024年第6期335-342,共8页
BACKGROUND Improved adenoma detection rate(ADR)has been demonstrated with artificial intelligence(AI)-assisted colonoscopy.However,data on the real-world appli-cation of AI and its effect on colorectal cancer(CRC)scre... BACKGROUND Improved adenoma detection rate(ADR)has been demonstrated with artificial intelligence(AI)-assisted colonoscopy.However,data on the real-world appli-cation of AI and its effect on colorectal cancer(CRC)screening outcomes is limited.AIM To analyze the long-term impact of AI on a diverse at-risk patient population undergoing diagnostic colonoscopy for positive CRC screening tests or sympt-oms.METHODS AI software(GI Genius,Medtronic)was implemented into the standard proced-ure protocol in November 2022.Data was collected on patient demographics,procedure indication,polyp size,location,and pathology.CRC screening outcomes were evaluated before and at different intervals after AI introduction with one year of follow-up.RESULTS We evaluated 1008 colonoscopies(278 pre-AI,255 early post-AI,285 established post-AI,and 190 late post-AI).The ADR was 38.1%pre-AI,42.0%early post-AI(P=0.77),40.0%established post-AI(P=0.44),and 39.5%late post-AI(P=0.77).There were no significant differences in polyp detection rate(PDR,baseline 59.7%),advanced ADR(baseline 16.2%),and non-neoplastic PDR(baseline 30.0%)before and after AI introduction.CONCLUSION In patients with an increased pre-test probability of having an abnormal colonoscopy,the current generation of AI did not yield enhanced CRC screening metrics over high-quality colonoscopy.Although the potential of AI in colonoscopy is undisputed,current AI technology may not universally elevate screening metrics across all situations and patient populations.Future studies that analyze different AI systems across various patient populations are needed to determine the most effective role of AI in optimizing CRC screening in clinical practice. 展开更多
关键词 Artificial intelligence COLONOSCOPY Adenoma detection rate SCREENING Colorectal adenoma
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9种芦荟属植物叶的结构和芦荟素含量的比较研究 被引量:29
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作者 沈宗根 李景原 +1 位作者 Yitzchak GUTTERMAN 胡正海 《西北植物学报》 CAS CSCD 2001年第2期278-286,T001,共10页
9种芦荟属植物叶的比较解剖研究结果表明 ,它们都具有明显的旱生叶的结构特征 ,其维管束的韧皮部内都有大型薄壁细胞。但其表皮角质膜的厚度、表面纹饰 ,气孔上、下腔的形状和大小 ,同化组织的层数、细胞分化情况 ,维管束的大小、分布... 9种芦荟属植物叶的比较解剖研究结果表明 ,它们都具有明显的旱生叶的结构特征 ,其维管束的韧皮部内都有大型薄壁细胞。但其表皮角质膜的厚度、表面纹饰 ,气孔上、下腔的形状和大小 ,同化组织的层数、细胞分化情况 ,维管束的大小、分布密度和其大型薄壁细胞占维管束的比例 ,中央贮水组织占叶横切面的比例等特征 ,在各种间存在差异 ,且性状稳定 ,可以作为该属内种间分类的解剖学指标。植物化学分析结果表明 ,9种植物叶内蒽醌类物质的主要种类和含量不同 ,其含量高、低与叶内维管束密度、大型薄壁细胞占维管束的比例以及同化组织的厚度密切相关 ,从而为芦荟属植物选育商业用良种提供了植物解剖学依据。 展开更多
关键词 芦荟属 比较解剖 植物化学 蒽醌类物质 芦荟素 百合科
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医院住院病人成本影响因素的研究 被引量:8
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作者 胡军 姜潮 +4 位作者 图易宸 Jerry.Han 刘启贵 刘宗航 司丹 《中国医院管理》 北大核心 2001年第4期20-22,共3页
目的:确定医院住院病人的影响因素,并对其进行定量测量。方法:采用SPSS、NOSA软件,用最小二乘法,建立医院床位、床位和出院病人人数的回归模式,对模型进行了对比分析,并对医院其他影响因素进行了相关分析,最后用岭回归方法建立了23个变... 目的:确定医院住院病人的影响因素,并对其进行定量测量。方法:采用SPSS、NOSA软件,用最小二乘法,建立医院床位、床位和出院病人人数的回归模式,对模型进行了对比分析,并对医院其他影响因素进行了相关分析,最后用岭回归方法建立了23个变量的医院成本定量的经济模型。结果:发现不只医院的规模对医院成本有影响,医院的利用对医院成本也有重要的作用。结论:指出提高病床周转次数,缩短医院住院病人平均住院日是降低医院住院病人成本的主要途径。 展开更多
关键词 住院病人 成本 医院管理 相关分析 多元回归分析
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The First Pilot Epigenetic Type Improvement of Neuropsychiatric Symptoms in a Polymorphic Dopamine D2 (-DRD2/ANKK (Taq1A)), OPRM1 (A/G), DRD3 (C/T), and MAOA (4R) Compromised Preadolescence Male with Putative PANDAS/CANS: Positive Clinical Outcome with Precision-Guided DNA Testing and Pro-Dopamine Regulation (KB220) and Antibacterial Therapies
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作者 Kenneth Blum Igor Elman +23 位作者 David Han Colin Hanna David Baron Ashim Gupta Shan Kazmi Jag Khalsa Debasis Bagchi Thomas McLaughlin Rajendra D. Badgaiyan Edward J. Modestino Drew Edwards Catherine A. Dennen Eric R. Braverman Abdalla Bowirrat Keerthy Sunder Kevin Murphy Nicole Jafari Foojan Zeine Paul R. Carney Mark S. Gold Kai-Uwe Lewandowski Alireza Sharafshah Aryeh R. Pollack Panayotis K. Thanos 《Open Journal of Immunology》 2024年第3期60-86,共27页
Pediatric autoimmune neuropsychiatric disorders associated with or without streptococcal and other bacterial infections (PANDAS/CANS) are emerging as a featured pediatric disorder. Although there is some controversy r... Pediatric autoimmune neuropsychiatric disorders associated with or without streptococcal and other bacterial infections (PANDAS/CANS) are emerging as a featured pediatric disorder. Although there is some controversy regarding treatment approaches, especially related to the behavioral sequelae, we have hypothesized in other published work that it is characterized by the rapid onset of Reward Deficiency Syndrome (RDS) in children. We propose utilizing a multi-systems biological approach involving the coupling of genetic addiction risk testing and pro-dopamine regulation (KB220/POLYGEN®) to help induce “dopamine homeostasis” in patients with PANDAS, especially those with known DNA-induced hypodopaminergia. This case study examines a 12-year-old Caucasian male with no prior psychiatric issues who presented with a sudden onset of severe anxiety, depression, emotional liability, and suicidal ideation. The patient underwent genotyping and the genetic addiction risk score (GARS) testing, which revealed risk polymorphisms in the dopamine D2 (-DRD2/ANKK (Taq1A), OPRM1 (A/G), DRD3 (C/T), and MAOA (4R) genes. These polymorphisms have been linked to hypodopaminergia. The patient was subsequently placed on research ID-KB220ZPBMPOLY (POLYGEN®), and albeit the possibility of bias, based upon self and parental assessment, a marked rapid improvement in psychiatric symptoms was observed. In the second phase of treatment (102 days utilizing KB220), the patient received standard antibody testing, which was positive for Lyme. Antibacterial therapy started immediately, and KB220z was discontinued to provide a wash-out period. A monotonic trend analysis was performed on each outcome measure, and a consistently decreasing trend was observed utilizing antibacterial therapy. Our recommendation, albeit only one case, is to utilize and further research a combined therapeutic approach, involving precision-guided DNA testing and pro-dopamine regulation along with antibacterial therapy, as well as glutathione to address offensive enhanced cytokines, in patients with suspected PANDAS/CANS. 展开更多
关键词 PANDAS CANS Genetic Addiction Risk Testing (GARS) Pro-Dopamine Regulation Hypodopaminergia Polymorphisms Antibacterial Therapy Infections
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雪藻高密度连续培养中生物量和花生四烯酸的高产率 被引量:15
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作者 刘建国 刘伟 +1 位作者 Zvi Cohen Amos Richmond 《海洋与湖沼》 CAS CSCD 北大核心 2002年第5期499-508,共10页
以 1 .4cm和 2 .8cm光径的平板光生物反应器 ,恒定高光强 [2 4 0 0 μE/(m2 ·s) ],通气、无菌高密度连续培养雪地绿藻 (简称雪藻 )。连续采收并补充等量新鲜培养液 ,当藻体生物量(以去灰分干重表示 ,AFDW)达恒态时 ,研究雪藻比生... 以 1 .4cm和 2 .8cm光径的平板光生物反应器 ,恒定高光强 [2 4 0 0 μE/(m2 ·s) ],通气、无菌高密度连续培养雪地绿藻 (简称雪藻 )。连续采收并补充等量新鲜培养液 ,当藻体生物量(以去灰分干重表示 ,AFDW)达恒态时 ,研究雪藻比生长速率 (SGR)、藻体的生物产量、总脂肪酸 (TFA)和花生四烯酸 (AA)产率。结果表明 ,尽管随着比生长速率增加 ,雪藻高密度连续培养体系的AA/TFA、TFA/AFDW和AA/AFDW三个指标有不同程度的降低 ,但生物产量、总脂肪酸及其花生四烯酸产出都相当高。 2 .8cm光径的平板光生物反应器中 ,雪藻SGR为0 .2d- 1 时 ,每平方米光照面积日获 35 .3gAFDW的高产量 ;SGR 0 .1 35d- 1 时 ,TFA产率最大 ,为7.0g/(m2 ·d) ,此时AA产率也最高 ,达 2 .6g/(m2 ·d)。尽管 1 .4cm光径的反应器的培养体积比前者下降了 5 0 % ,但细胞浓度明显提高 ,单位光照面积的AFDW和TFA最大日产率只下降了37.3%和 1 0 % ,分别为 2 2 .1和 6.3g/(m2 ·d) ,而AA的最大日产率也是 2 .6g/(m2 ·d)。结果还表明 ,氮或磷营养亏缺能明显提高雪藻AA含量的各项指标 ,同时高光强也有利于雪藻累积AA。 展开更多
关键词 雪藻 高密度培养 平板光生物反应器 花生四烯酸 产率 比生长速率 绿藻
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有高温相变的电工钢热轧起浪的有限元分析 被引量:6
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作者 曹建国 唐慧 +3 位作者 杨光辉 温盾 周云松 赖金权 《哈尔滨工业大学学报》 EI CAS CSCD 北大核心 2016年第1期146-151,共6页
针对电工钢自由规程轧制过程起浪问题,开展电工钢不同冷却条件下的连续冷却相变转变温度分析测定和Gleeble热模拟实验,发现电工钢在975~875℃的奥氏体-铁素体两相区,随着轧制温度降低,变形抗力反而减小;电工钢大量同宽自由规程轧制下的... 针对电工钢自由规程轧制过程起浪问题,开展电工钢不同冷却条件下的连续冷却相变转变温度分析测定和Gleeble热模拟实验,发现电工钢在975~875℃的奥氏体-铁素体两相区,随着轧制温度降低,变形抗力反而减小;电工钢大量同宽自由规程轧制下的工作辊出现严重的不均匀的箱型磨损和明显的热胀,综合辊形变化显著.考虑电工钢两相区变形抗力差异和综合辊形变化,建立电工钢热轧过程轧辊轧件的三维弹塑性耦合有限元模型,仿真分析轧制力、弯辊与窜辊对承载辊缝形状的影响,研究摩擦系数、压下量与轧制速度对带钢宽度方向内应力变化规律的影响,采用Shohet板形判据确定电工钢比例凸度残差变化路径,明确电工钢在“平坦死区”较大的上游机架出现“异常起浪”的生成过程.该方法为电工钢热轧板形的浪形控制提供了依据. 展开更多
关键词 电工钢 热轧 热塑性变形 有限元建模 板形控制
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Y-梯度广义最小二乘加权校正的土壤速效氮野外原位光谱预测 被引量:7
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作者 齐海军 Karnieli Arnon 李绍稳 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2018年第1期171-175,共5页
土壤速效氮是影响作物生长发育的重要养分指标。野外原位可见近红外光谱(VIS-NIR)分析技术具有快速无损等特点,对速效氮的定量预测具有较好的应用前景。野外条件下进行原位光谱采集更节省人力物力,且为土壤养分实时传感器的开发提供了... 土壤速效氮是影响作物生长发育的重要养分指标。野外原位可见近红外光谱(VIS-NIR)分析技术具有快速无损等特点,对速效氮的定量预测具有较好的应用前景。野外条件下进行原位光谱采集更节省人力物力,且为土壤养分实时传感器的开发提供了数据基础。但由于野外原位光谱中通常存在大量的无关环境因子干扰信息,易导致回归模型预测精度降低,达不到实用要求。针对位于以色列中部和北部的两个试验点共76个样本开展研究,提出利用Y-梯度广义最小二乘加权算法(Y-GLSW)对样本的野外原位VIS-NIR反射率光谱(350~2 500nm)进行滤波校正,以提高回归模型的预测能力。首先使用SG平滑、一阶导数变换、标准正态变换等常规方法对原始光谱进行预处理和变换;在此基础上再使用Y-GLSW构建滤波模型对变换后的光谱进行滤波校正;最后使用偏最小二乘回归算法(PLS-R)分别结合原始光谱RW、预处理变换后的光谱PPT和滤波校正后的光谱Y-GLSW建立回归分析模型对速效氮进行定量预测。结果表明:利用RW光谱建立的回归预测模型是不可靠的;利用PPT光谱建立的回归模型在测试集的相对分析误差(RPD)为1.41,解释总方差占实际总方差之比(SSR/SST)为0.57,模型具有一定的可靠性;Y-GLSW光谱建立的回归模型在测试集的RPD和SSR/SST分别为2.07和0.69,相对于PPT模型分别提高了46.81%和21.05%。因此,利用Y-GLSW对野外原位VIS-NIR光谱进行滤波校正,能够有效去除光谱中的无关信息数据,提高模型的预测精度和解释能力。 展开更多
关键词 土壤速效氮 野外检测 光谱校正 回归模型 Y-梯度广义最小二乘加权
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光照、温度和盐分对梭梭种子萌发的影响 被引量:116
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作者 黄振英 张新时 +1 位作者 Yitzchak GUTTERMAN 郑光华 《植物生理与分子生物学学报》 CAS CSCD 2001年第3期275-280,共6页
梭梭是我国西北荒漠中分布的多年生植物 ,属中亚荒漠植被成分。其种子萌发的最适温度为 10℃ ,亚适宜温度为 15~ 2 0℃。从 2 0℃起 ,温度越高 ,萌发比率越低。种子无论在光下和暗中都能萌发 ,萌发率无显著性差异。浓度低于 0 .2mol/L... 梭梭是我国西北荒漠中分布的多年生植物 ,属中亚荒漠植被成分。其种子萌发的最适温度为 10℃ ,亚适宜温度为 15~ 2 0℃。从 2 0℃起 ,温度越高 ,萌发比率越低。种子无论在光下和暗中都能萌发 ,萌发率无显著性差异。浓度低于 0 .2mol/L的NaCl溶液对萌发的影响不大 ;但从 0 .8mol/L起 ,萌发率随着浓度增高而降低 ,直至为零。将在盐溶液中处理 9d的种子转移至蒸馏水后 ,原来较高浓度下的种子具有较高的萌发恢复率。不同浓度下的种子的萌发率和萌发恢复率要比蒸馏水中的低 ,表明NaCl处理后的部分种子永久地失去萌发力。 展开更多
关键词 梭梭 光照 温度 土壤盐分 种子萌发 萌发恢复
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Comparison of Germination Strategies of Artemisia ordosica with Its Two Congeners from Deserts of China and Israel 被引量:50
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作者 黄振英 Yitzchak GUTTERMAN 《Acta Botanica Sinica》 CSCD 2000年第1期71-80,共10页
Artemisia ordosica Krasch. is a dominant shrub occurring mainly on stable sand dunes in the Gobi Desert of China, in the Mongolian phytogeographic region. Achenes of A. ordosica germinate in light but poorly in ... Artemisia ordosica Krasch. is a dominant shrub occurring mainly on stable sand dunes in the Gobi Desert of China, in the Mongolian phytogeographic region. Achenes of A. ordosica germinate in light but poorly in dark and light is the limiting factor regulating the achene germination in sand depth. Achenes germinate in spring or autumn with an optimal temperature of 20 ℃. Achene mucilage can absorb large amounts of water and has important ecological function. Salt concentrations and sand moisture may regulate achene germination in sand. A. ordosica, A. sphaerocephala Krasch. and A. monosperma Delile. from different climates have similar responses to light, the underground location of achene, and sand moisture. Percentage of seedling emergence from different levels of sand depth is depends on the specific, temperature and intensity of light penetrating through the sand depths, as well as on sand moisture. The desert sand habitat seems to have had a dominant influence on the evolution of the germination strategies of these 3 Artemisia species. 展开更多
关键词 ARTEMISIA mucilaginous achenes sand temperatures light sand depth sand moisture germination strategies
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Anatomy, Histochemistry and Phytochemistry of Leaves in Aloe vera var. chinensis 被引量:5
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作者 沈宗根 Elena CHAUSER-VOLFSON +1 位作者 Yitzchak GUTTERMAN 胡正海 《Acta Botanica Sinica》 CSCD 2001年第8期780-787,共8页
A multidisciplinary approach-anatomy, histochemistry and phytochemistry-was used to investigate the leaf structure, the content and the storage location of barbaloin in the leaves of Aloe vera L. var. chinensis (Haw.)... A multidisciplinary approach-anatomy, histochemistry and phytochemistry-was used to investigate the leaf structure, the content and the storage location of barbaloin in the leaves of Aloe vera L. var. chinensis (Haw.) Berg. Xeromorphic characteristics including secondary thickened epidermal cell walls, thicker cuticle, ambiguous differentiation of spongy and palisade tissues in the chlorenchyma, and well-developed aquiferous tissue could be seen in the leaves. Several large parenchymatous cells were observed at the phloem pole of the first ring of vascular bundles. The secondary ring of vascular bundles in the leaf base and the stomata, which are surrounded by five cells, have some classification significance in this species. The density of vascular bundles, the content of barbaloin and the intensity of histochemical reaction differed among leaf numbers Ll (annual leaf), L2 (biennial leaf), L3 (triennial leaf) and L4 (quadrennial leaf), and in different parts of the leaf. These three factors were highest in the youngest leaf, Ll, and top parts of all the leaves and lowest in the basal parts and the oldest leaf, L4. The density of vascular bundles had a positive correlation to the content of barbaloin. The histochemical results revealed that the small sheath cells that surrounded the bundles might be the location of barbaloin synthesis and the large parenchymatous cells beneath the sheath might be the storage places of this metabolite. 展开更多
关键词 Aloe vera var. chinensis leaf structure barbaloin content density of vascular bundles histochemical reaction
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基于CAD和CFD技术的高效叶片泵流场仿真与优化分析 被引量:4
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作者 曹建国 于亮 杨光辉 《徐州工程学院学报(自然科学版)》 CAS 2015年第2期1-6,共6页
为了提高高效节能叶片泵的设计效率和降低实际工况的不确定性产生的"无效能耗",基于CAD和CFD技术,对高效叶片泵流场进行仿真与优化分析.以SS300-560型离心泵为对象,采用Pro/E和Fluent软件分别建立了高效叶片泵三维造型和CFD模... 为了提高高效节能叶片泵的设计效率和降低实际工况的不确定性产生的"无效能耗",基于CAD和CFD技术,对高效叶片泵流场进行仿真与优化分析.以SS300-560型离心泵为对象,采用Pro/E和Fluent软件分别建立了高效叶片泵三维造型和CFD模型,结合实际条件仿真分析了叶轮内部流动的压力场和速度场,明确了具体叶型产生的局部湍流及汽蚀现象;建立了以离心泵效率最大、汽蚀余量最小为目标,以无驼峰曲线和无过载为约束的多目标函数优化模型,采用遗传算法对叶轮设计参数进行求解,提高了泵体效率并降低了汽蚀余量. 展开更多
关键词 离心式叶片泵 数学建模 流场 CFD
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绿色发展的国际先进经验及其对中国的启示 被引量:28
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作者 杨宜勇 吴香雪 杨泽坤 《新疆师范大学学报(哲学社会科学版)》 CSSCI 北大核心 2017年第2期18-24,共7页
随着经济的不断发展,经济增长与资源环境之间的张力越来越大,给中国经济社会的可持续发展带来沉重压力。中共十八届五中全会提出"五大发展理念",将绿色发展提高到突出位置,强调走绿色发展之路,以实现经济社会发展与资源环境... 随着经济的不断发展,经济增长与资源环境之间的张力越来越大,给中国经济社会的可持续发展带来沉重压力。中共十八届五中全会提出"五大发展理念",将绿色发展提高到突出位置,强调走绿色发展之路,以实现经济社会发展与资源环境的共生共荣。国外发达国家已有成功的绿色发展经验,值得合理借鉴。走绿色发展之路要立法先行,严格监管,综合利用各种绿色发展的政策工具,统筹绿色发展规划与重点治理相结合,强化企业的作用,不断创新绿色发展技术,要求社会公众积极参与,并加强环境教育,提高全社会环境保护的意识。 展开更多
关键词 绿色发展 国际经验 绿色经济 生态文明
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基于无干扰的云计算环境行为可信性分析 被引量:11
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作者 张帆 张聪 +2 位作者 陈伟 胡方宁 徐明迪 《计算机学报》 EI CSCD 北大核心 2019年第4期736-755,共20页
云安全是目前云计算研究的热点之一.作为云安全基础的可信计算,目前仍存在一些关键问题有待解决,这使得云安全事实上是有缺陷的.针对可信计算中的动态行为可信度量问题,本文提出了一种基于无干扰的云环境行为可信性分析方法.首先,基于... 云安全是目前云计算研究的热点之一.作为云安全基础的可信计算,目前仍存在一些关键问题有待解决,这使得云安全事实上是有缺陷的.针对可信计算中的动态行为可信度量问题,本文提出了一种基于无干扰的云环境行为可信性分析方法.首先,基于可信计算组织TCG(Trusted Computing Group)和学术界对于"可信"的定义,给出了行为可信的判定等式.进一步地,建立了基于状态递归等价的行为可信的充要条件,解决了目前尚没有有效的行为可信性验证方法的问题目前没有见到类似结论.最后,本文给出了实验示例,证明了方法是有效的. 展开更多
关键词 无干扰 动态行为可信 云安全 可信计算 云计算
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20世纪60年代以来中亚地区的盐尘暴(英文) 被引量:10
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作者 Orlovsky N Orlovsky L +2 位作者 杨有林 卢琦 肖洪浪 《中国沙漠》 CSCD 北大核心 2003年第1期18-27,共10页
中亚是盐尘暴高发地区之一,由自然因素和人文因素引起的沙质和盐质荒漠广泛分布。据初步估计,平均每年从干涸的咸海盆地通过空气输送出的盐尘为0 5×106t到20×106~30×106t不等。这些盐尘的沉降受地形、风力和距源地的距... 中亚是盐尘暴高发地区之一,由自然因素和人文因素引起的沙质和盐质荒漠广泛分布。据初步估计,平均每年从干涸的咸海盆地通过空气输送出的盐尘为0 5×106t到20×106~30×106t不等。这些盐尘的沉降受地形、风力和距源地的距离的影响。中亚地区盐尘暴的季节性和频率受降雨的影响很大。盐尘不仅影响气候,还会给人们的健康与经济活动带来不利影响。通过对过去近40年研究工作的总结和分析,对中亚地区盐尘暴的现状及其未来变化有了基本的认识:(1)盐尘的产生、搬运和沉积在中亚地区是目前的普遍现象,特别是在咸海区域。(2)过去近40年的咸海危机证明:适当的自然保护需要很长的时间和大量的资本投入。(3)要缓和目前的现状并创建一个稳定的、健康的环境,在实施各项计划中需要综合考虑社会、经济与生态问题。 展开更多
关键词 中亚地区 盐尘暴 沙漠化 人类因素 咸海 风力 地形
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软件实时可信度量:一种无干扰行为可信性分析方法 被引量:6
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作者 张帆 徐明迪 +3 位作者 赵涵捷 张聪 刘小丽 胡方宁 《软件学报》 EI CSCD 北大核心 2019年第8期2268-2286,共19页
可信度量作为可信计算“度量、存储、报告”三大核心功能的基础,到目前为止仍未有有效的数学理论以及运行时(runtime)度量方法.其困难在于3点:一是如何建立涵盖不同主流“可信”定义的通用数学模型;二是如何依托数学模型构建运行时可信... 可信度量作为可信计算“度量、存储、报告”三大核心功能的基础,到目前为止仍未有有效的数学理论以及运行时(runtime)度量方法.其困难在于3点:一是如何建立涵盖不同主流“可信”定义的通用数学模型;二是如何依托数学模型构建运行时可信度量理论;三是如何将上述模型和理论映射到真实信息系统以形成可实践的实时度量方法.提出了一种基于无干扰的软件实时可信度量方法.首先,利用无干扰模型解释了各类主流的可信定义,表明无干扰模型可以作为可信计算通用数学模型的一个选择.其次,基于无干扰模型提出了一种软件实时可信度量理论,其基本思想是将系统调用视作原子动作,将软件真实行为α看做系统调用的序列,并基于α中所有系统调用所属安全域之间的无干扰关系计算软件理论上的预期行为β,得到α和β之后,利用无干扰等式判定两者之间是否存在偏差,从而实现对软件可信性的实时度量.最后,给出了实时可信度量算法,算法的时间复杂性为O(1).原型实验结果表明了所提出的方法的有效性. 展开更多
关键词 可信度量 无干扰 行为可信 可信计算 软件安全
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The role of Epstein-Barr virus in multiple sclerosis:from molecular pathophysiology to in vivo imaging 被引量:8
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作者 Yi Guan Dejan Jakimovski +2 位作者 Murali Ramanathan Bianca Weinstock-Guttman Robert Zivadinov 《Neural Regeneration Research》 SCIE CAS CSCD 2019年第3期373-386,共14页
Multiple sclerosis(MS) is a disease of the central nervous system characterized by inflammation, demyelination, and neuronal damage. Environmental and genetic factors are associated with the risk of developing MS, but... Multiple sclerosis(MS) is a disease of the central nervous system characterized by inflammation, demyelination, and neuronal damage. Environmental and genetic factors are associated with the risk of developing MS, but the exact cause still remains unidentified. Epstein-Barr virus(EBV), vitamin D, and smoking are among the most well-established environmental risk factors in MS. Infectious mononucleosis, which is caused by delayed primary EBV infection, increases the risk of developing MS. EBV may also contribute to MS pathogenesis indirectly by activating silent human endogenous retrovirus-W. The emerging B-cell depleting therapies, particularly anti-CD20 agents such as rituximab, ocrelizumab, as well as the fully human ofatumumab, have shown promising clinical and magnetic resonance imaging benefit. One potential effect of these therapies is the depletion of memory B-cells, the primary reservoir site where EBV latency occurs. In addition, EBV potentially interacts with both genetic and other environmental factors to increase susceptibility and disease severity of MS. This review examines the role of EBV in MS pathophysiology and summarizes the recent clinical and radiological findings, with a focus on B-cells and in vivo imaging. Addressing the potential link between EBV and MS allows the better understanding of MS pathogenesis and helps to identify additional disease biomarkers that may be responsive to B-cell depleting intervention. 展开更多
关键词 EPSTEIN-BARR virus multiple SCLEROSIS MENINGEAL inflammation magnetic resonance imaging LEPTOMENINGEAL contrast enhancement MONONUCLEOSIS human endogeneous retrovirus-W B-CELLS
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Axon degeneration: make the Schwann cell great again 被引量:10
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作者 Keit Men Wong Elisabetta Babetto Bogdan Beirowski 《Neural Regeneration Research》 SCIE CAS CSCD 2017年第4期518-524,共7页
Axonal degeneration is a pivotal feature of many neurodegenerative conditions and substantially accounts for neurological morbidity. A widely used experimental model to study the mechanisms of axonal degeneration is W... Axonal degeneration is a pivotal feature of many neurodegenerative conditions and substantially accounts for neurological morbidity. A widely used experimental model to study the mechanisms of axonal degeneration is Wallerian degeneration (WD), which occurs after acute axonal injury. In the peripheral nervous system (PNS), WD is characterized by swift dismantling and clearance of injured axons with their myelin sheaths. This is a prerequisite for successful axonal regeneration. In the central nervous system (CNS), WD is much slower, which significantly contributes to failed axonal regeneration. Although it is well documented that Schwann cells (SCs) have a critical role in the regenerative potential of the PNS, to date we have only scarce knowledge as to how SCs 'sense' axonal injury and immediately respond to it. In this regard, it remains unknown as to whether SCs play the role of a passive bystander or an active director during the execution of the highly orchestrated disintegration program of axons. Older reports, together with more recent studies, suggest that SCs mount dynamic injury responses minutes after axonal injury, long before axonal breakdown occurs. The swift SC response to axonal injury could play either a pro degenerative role, or alternatively a supportive role, to the integrity of distressed axons that have not yet committed to degenerate. Indeed, supporting the latter concept, recent 昀ndings in a chronic PNS neurodegeneration model indicate that deactivation of a key molecule promoting SC injury responses exacerbates axonal loss. If this holds true in a broader spectrum of conditions, it may provide the grounds for the development of new glia-centric therapeutic approaches to counteract axonal loss. 展开更多
关键词 Wallerian degeneration NEURODEGENERATION GLIA OLIGODENDROCYTES MYELIN DEDIFFERENTIATION
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