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Search Results: 1 - 10 of 253470 matches for " 李韦 "
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疏勒河流域极端降水特征分析
Characteristics of Extreme Precipitation in Shule River Basin
 [PDF]

王月华, 占玲,
Journal of Water Resources Research (JWRR) , 2015, DOI: 10.12677/JWRR.2015.46067
Abstract:
疏勒河流域是我国河西走廊内陆河流域的重要组成部分。在全球气候变暖背景下,研究其极端降水特征变化对于了解西北内陆河流域生态水文过程以及对气候变化的响应均具有重要意义。本文以疏勒河流域4个气象站点1960~2012年逐日降水资料为基础,采用Mann-Kendall检验、Pettitt方法、气候倾向率、滑动平均和小波分析等方法,对研究区年降水总量、最大一天降水量的趋势变化、变点特征和周期特征进行分析,并对极端降水发生频次进行讨论。结果表明,近50多年来研究区玉门镇站、安西站和敦煌站年降水总量和最大一天降水量均呈波动上升趋势,上升幅度分别为3.0~5.3 mm/10a和0.7~1.0 mm/10a。各站点年降水总量序列基本存在11~13年长周期、6~7年中周期和2~4年短周期,短周期较为显著;最大一天降水量序列存在17~18年长周期、6~10年中周期和3~4年短周期,中周期和长周期较为显著。除马鬃山站以外,玉门镇站、安西站和敦煌站2000年以后极端降水发生频次明显增加,这与年降水总量和最大一天降水量变化趋势较为一致。
Under the background of global warming, extreme climate events are proved to occur more frequently than before in most regions of China. Shule River basin, located in the Northwest of China, is one of the important parts of inland river basins in Hexi corridor. Studying the characteristics of extreme precipi-tation in Shule River basin is significant for better understanding the local eco-hydrological processes and its response to climate change. Based on the daily precipitation data from 1960 to 2012 at four me-teorological stations, the trends, change points and period features of the annual total precipitation (ATP) and the annual maximum precipitation for one day (AMP) over Shule River basin are investigated by means of Mann-Kendall test, Pettitt test, Climate trend rate, the five-year moving average method and Morlet wavelet analysis. In addition, the occurrence number of extreme precipitation over the study area is also discussed in this paper. Results show that, the increasing trends are found for the ATP and AMP series at Yumenzhen station, Anxi station and Dunhuang station with the climate trend rates of 3.0 - 5.3 mm/10a and 0.7 - 1.0 mm/10a. No significant change points are found for the ATP and AMP series with Pettitt test. Based on the wavelet analysis, the ATP series are found to have a long period of 11 - 13 years, a middle period of 6 - 7 years and a short period of 2 - 4 years, in which the short period shows more out-standing. The AMP series have a long period of 17 - 18 years, a middle period of 6 - 10 years, and a short period of 2 - 4 years, with more significant long and middle periods. The occurrence numbers of extreme precipitation at three stations (Yumenzhen, Anxi and Dunhuang stations) are found to have an increasing tendency after the year of 2000.
三七有效成分对免疫性肝损伤的保护作用
,
天津医药 , 2014,
Abstract: ?【】目的研究三七有效成分三七总皂苷、总黄酮及多糖对小鼠免疫性肝损伤的保护作用。方法昆明种小鼠60只随机分为正常组(a组)、模型组(b组)、三七总皂苷组(c组)、三七总黄酮组(d组)、三七多糖组(e组)。c、d、e组分别给予三七总皂苷、三七总黄酮、三七多糖灌胃,1次/d,14d后b、c、d和e组于尾静脉注射卡介苗,26d于尾静脉注射脂多糖,禁食12h后于眼球静脉丛采血,检测血清中丙氨酸转氨酶(alt)、总超氧化物歧化酶(t-sod)、白细胞介素-4(il-4)的含量;取肝、脾、胸腺计算脏器指数;另取肝脏做病理学检查。结果与b组比较,c、d、e组小鼠肝、脾、胸腺指数、血清alt水平明显降低(p<0.01),il-4、t-sod显著升高(p<0.01);病理学示c、d、e组肝脏炎症细胞浸润、水肿和点状、片状坏死程度均比b组明显减轻。结论三七总皂苷、总黄酮及多糖对免疫性肝损伤均有明显的保护作用。
泡打粉的ph值测定中存在问题之分析
,英姿
食品科学 , 1999,
Abstract: ?通过分析泡打粉的组成及其在溶液中的反应机理对ph值的影响,确定了泡打粉的ph值在检测操作中的合适温度及时间,并探讨了不同组成对ph值的影响。
术前栓塞鼻咽纤维血管瘤的疗效分析
The Efficacy of Pre-Surgical Embolization of Nasopharyngeal Angiofibroma
 [PDF]

传军, 叶丹, 逄杰, 新民
Medical Diagnosis (MD) , 2015, DOI: 10.12677/MD.2015.53009
Abstract: 目的:探讨术前栓塞鼻咽部纤维血管瘤供血动脉的临床疗效。方法:采用Seldinger技术,超选择插管对肿瘤颈外供血动脉进行栓塞后1~3 d内手术切除。结果:12例患者,患侧颌内动脉供血9例,合并咽升动脉供血1例。双侧颌内动脉分支供血2例,患侧颌内动脉及颈内动脉分支供血1例;。均未发生严重并发症;栓塞后11例完整手术切除,1例部分切除拟分期手术。术中平均出血约380 ml。结论:术前血管栓塞鼻咽部血管瘤可有效减少术中出血,并增加肿瘤切除率。
Objective: To investigate the clinical efficacy of pre-surgical embolization of nasopharyngeal angiofibroma. Methods: Using Seldinger technique, 12 cases with nasopharyngeal angiofibroma underwent superselective feeding arteries emboilization, and then 1 - 3 days later, the angiofibroma was cut. The intraoperative blood loss was recorded. Results: For the 12 cases, 9 cases of nasopharyngeal angiofibroma were supplied by single-side internal maxillary artery, and 1 case combined with ascending pharyngeal artery, the bilateral internal axillary artery was in 2 patients, and the same lateral axillary artery and the branches of the internal carotid artery was in 1 patient. No serious complication happened after embolization. After thrombosis, in 11 cases underwent complete surgical resection, 1 case was of resection to staging surgery. All lesions were radical removed. The average intraoperative blood loss was 380 ml. Conclusion: The pre-surgical embolization of nasopharyngeal angiofibroma can reduce the intraoperative blood loss and increase radical resected rate.
纵向数据下线性指数分布参数的经验Bayes双边检验
The Empirical Bayes Two-Sided Tests for the Parameter of Linear Exponential Distribution under Longitudinal Data
 [PDF]

罗修辉, 程东, 进立
Statistics and Applications (SA) , 2016, DOI: 10.12677/SA.2016.53022
Abstract: 基于纵向数据下,本文讨论了在平方损失函数下线性指数分布参数的双边检验问题,利用Markov不等式证明了构造的经验贝叶斯双边检验函数具有渐近最优性,并获得了其收敛速度。
In the case of longitudinal data, this paper studies two-side test problem of linear exponential dis-tribution parameters under square loss function. By applying Markov inequality, the EB test rules for parameter of the linear exponential distribution are constructed and the asymptotically optimal property is obtained. Finally, we obtain the convergence rate of the proposed EB test under suitable conditions.
蜘蛛抱蛋属(百合科)二新种
光照,毅刚
中国科学院研究生院学报 , 2003,
Abstract: 报道了在广西发现的2个百合科蜘蛛抱蛋属Aspidistra新种,即乳突蜘蛛抱蛋A. papillata G. Z. Li和环江蜘蛛抱蛋A. huanjiangensis G. Z. Li&Y. G. Wei。乳突蜘蛛抱蛋与大花蜘蛛抱蛋A. tonkinensis(Gagner. )F. T. Wang&K. Y. Lang近缘。它们的共同特征是:花单生;花被裂片两侧彼此覆盖;柱头盾状,边缘3裂,上表面具3条辐射状沟缝。不同点是:乳突蜘蛛抱蛋植株较大花蜘蛛抱蛋的粗大;叶柄较粗;叶片椭圆形或长椭圆形;花被阔钟
西南第三次人口科学讨论会综述
士钊,仪 ?
期刊检索-中国人口科学 , 1992,
Abstract: <正>四川、贵州、云南、广西四省区地理位置、自然条件相近,人口和经济发展有着许多共同之处。随着区域经济技术联合协作的发展,人口工作者也加强联合协作,共同组织召开过两次人口研讨会并取得了可喜的成果。为了充分发挥第四次人口普查资料的作用,使人口科学研究成果更好地为政府决策服务,四省区人口普查办公室于1992年6月28日~
东亚冬季风的区域差异和突变特征
道明,崇银-
高原气象 , 2009,
Abstract: 使用1957年9月1日\_2002年8月31日共45年ECWMF的温度场、海平面气压场和风场再分析资料,采用EOF、REOF相结合的方法,对东亚冬季风进行了区域划分,即蒙古区、日本区及中国东部区。分析3个分区的区域平均1000hPa温度、海平面气压、风场和降水随时间的变化特征后,发现各个分区的物理量演变存在非常明显的差异,认为对冬季风活动进行区划研究是必要的;同时发现风场中风向在冬季风的建立和撤退时较易出现突变特征。对各个分区的风场进行了气候突变检验,得到各个分区冬季风建立和撤退的不同日期。
一种新的用于各向同性损伤模型的四参数等效应变
,同春
工程力学 , 2005,
Abstract: 基于Hsieh-Ting-Chen强度破坏准则的思想,提出由于求解混凝土各向同性损伤模量的等效应变.首先通过混凝土试件材料特性以及强度试验资料来确定四参数,然后求解出由多轴应力状态下的应变退化得到的等效应变以及相应的损伤模量.对一混凝土立方体试件进行有限元分析,计算结果表明:采用该等效应变计算所得的应力应变曲线与试验曲线吻合性较好,从而说明了该等效应变的合理性,并且可说明利用该等效应变的损伤模型不但可以描述单轴应力状态下混凝土破坏的全过程曲线,而且能描述多轴应力状态下混凝土破坏的全过程曲线.该等效应变形式单一,计算简单.
温室覆盖材料的热学性质
惟毅,雪松
工程热物理学报 , 2005,
Abstract: 结合理论与实验,本文对温室内常用的几种覆盖材料的热学性质进行了研究。通过实验测试了不同材料的全辐射透射率,在一些大型温室中进行了温室太阳辐射的实验研究。在实验的基础上,对温室内外的太阳辐射强度进行了模拟。应用传热学基本原理,在合理假设的基础上,对温室覆盖材料的传热系数进行了模拟。
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