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Characteristics of Temperature Change in China over the Last 2000 years and Spatial Patterns of Dryness/Wetness during Cold and Warm Periods 被引量:10
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作者 Quansheng GE Haolong LIU +2 位作者 Xiang MA Jingyun ZHENG Zhixin HAO 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2017年第8期941-951,共11页
This paper presents new high-resolution proxies and paleoclimatic reconstructions for studying climate changes in China for the past 2000 years. Multi-proxy synthesized reconstructions show that temperature variation ... This paper presents new high-resolution proxies and paleoclimatic reconstructions for studying climate changes in China for the past 2000 years. Multi-proxy synthesized reconstructions show that temperature variation in China has exhibited significant 50–70-yr, 100–120-yr, and 200–250-yr cycles. Results also show that the amplitudes of decadal and centennial temperature variation were 1.3℃ and 0.7℃, respectively, with the latter significantly correlated with long-term changes in solar radiation, especially cold periods, which correspond approximately to sunspot minima. The most rapid warming in China occurred over AD 1870–2000, at a rate of 0.56°± 0.42℃(100 yr)^(-1); however, temperatures recorded in the 20 th century may not be unprecedented for the last 2000 years, as data show records for the periods AD 981–1100 and AD1201–70 are comparable to the present. The ensemble means of dryness/wetness spatial patterns in eastern China across all centennial warm periods illustrate a tripole pattern: dry south of 25°N, wet from 25°–30°N, and dry to the north of 30°N. However, for all centennial cold periods, this spatial pattern also exhibits a meridional distribution. The increase in precipitation over the monsoonal regions of China associated with the 20 th century warming can primarily be attributed to a mega El Nino–Southern Oscillation and the Atlantic Multidecadal Oscillation. In addition, a significant association between increasing numbers of locusts and dry/cold conditions is found in eastern China. Plague intensity also generally increases in concert with wetness in northern China, while more precipitation is likely to have a negative effect in southern China. 展开更多
关键词 temperature change dry-wet spatial pattern cold and warm periods last 2000 years China
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EVOLUTION LAW OF DRYNESS AND WETNESS IN KUNMING IN RECENT 300 YEARS
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作者 严华生 谢应齐 +3 位作者 赵筱青 曹杰 周传喜 罗兰仙 《Journal of Tropical Meteorology》 SCIE 1998年第2期208-214,共7页
Using indexes of dryness and wetness in historical record over the recent recent years and rainfall data over the tatest century, the work involves itself with the study of climatological evolution of dryness and wetn... Using indexes of dryness and wetness in historical record over the recent recent years and rainfall data over the tatest century, the work involves itself with the study of climatological evolution of dryness and wetness. periodic variations of climate and interannual laws of variation. The discussion also covers the subjects of effects of El Nino. sunspot, predictors of general circulation on climatic variation of dryness and wetness. There arc main conclusions as follows: (1) The main cyclic variations of climate are 40 and 11 years in Kunming. the former being subject to that of El Nino and the latter to that of sunspots. They are two principal factors for periodic variations of dryness and wetness in Kunming. (2) A close relationship exists between interannual variations and general circulation factors for Kunming. The comprehensive influence as imposed by ENSO and allocations of W.C.E. patterns of circulation in the westerly are ma.tor weather and climate causes for the interannual variations of precipitation in Kunming. 展开更多
关键词 DISASTERS by dryness and wetness CLIMATIC variation FACTORS of influence
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FEATURES OF DRYNESS AND WETNESS IN GUANGDONG PROVINCEOVER THE PAST FOUR DECADES
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作者 贺海晏 《Journal of Tropical Meteorology》 SCIE 1999年第1期33-42,共10页
Precipitation data from 86 observing Stations for the past four decades (from the first operational use to 1994) are used to study and discuss the character of annually mean distribution in Guangdong. Grades of drynes... Precipitation data from 86 observing Stations for the past four decades (from the first operational use to 1994) are used to study and discuss the character of annually mean distribution in Guangdong. Grades of dryness and wetness on a year-to-year basis are determined and preliminary features of dryness and wetness are discussed for the whole of the province and individual regions according to a 5-grade standard of division. The result has shown that there is on an average a rainfall of 1748 mm per year across the province, with four major centers of maxima (of annual rainfall over 2000 mm) at Enping, Qingyuan, Haifeng and Longmen. For the mean across the province, the years 1959. 1 961. 1973.1975, 1991 are anomalously wet and the years 1956, 1963, 1977 and 1991 are anomalously dry. of them, 1973 is the unusually wet year (with the absolute value of precipitation anomaly over twice as large as the standard deviation) and 1956 and 1963 are the usual dry years. For the occurrence frequency of unusually wetness and dryness over individual river valleys in the province, there are more years of dryness in the valleys of the Xijiang and Dongjiang Rivers. More years of wetness in that of the Jianjiang River, and only years of wetness instead of years of dryness in the valleys of Beijiang and Hanjiang Rivers. 展开更多
关键词 GUANGDONG PRECIPITATION dryness and wetness
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Observed dryness and wetness variability in Shanghai during 1873-2005
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作者 张增信 张强 +2 位作者 张金池 邹兰军 江剑民 《Journal of Geographical Sciences》 SCIE CSCD 2009年第2期143-152,共10页
Dryness and wetness variations on different time scales in Shanghai were analyzed using the Standardized Precipitation Index (SPI) based on monthly precipitation data for 1873-2005. The SPI on scales of 3, 6, 12 and... Dryness and wetness variations on different time scales in Shanghai were analyzed using the Standardized Precipitation Index (SPI) based on monthly precipitation data for 1873-2005. The SPI on scales of 3, 6, 12 and 24 months has been calculated. The SPI on 3, 6, 12 and 24 months present 4 wet periods prevailed during 1873-1885, 1904-1923, 1938-1960 and 1983-2005, and 3 dry episodes during 1886-1903, 1924-1937 and 1961-1982. Significant periods of higher wavelet power in the SPI-24 months occurred on the time scales of 2-7-year band in around 1880-1890, 1910-1950 and 1970-1990, and at 8-15-year band in 1920-1960 and 1965-2000 respectively. Periodicities in the SOl and ENSO indices are similar to those in SPI-24 months with little difference, namely, in the SPI-24 months, there are significant periods at the 2-7- and 8-15-year bands during 1930-1940. The periodicity components in individual SPI-24 months, SOl and ENSO indices are more complicated, showing the wetness and dryness variability in Shanghai is controlled by more than one physical factors. The research results indicate that the Shanghai area has experienced dryness and wetness variability on different time scales during the past 133 years. 展开更多
关键词 dryness and wetness SPI continuous wavelet transform SHANGHAI
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Wet and Dry Tribological Behaviors of Circular Islandic Protrusion Patterns on M2 Steel Discs under Spinning Condition 被引量:1
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作者 马庆贤 董光能 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2008年第5期720-726,共7页
Under spinning conditions, lubricant on islandic spot patterned M2 steel disc experiences centrifugal and tangential force components. Depending upon the relative position of the spots and the flow of lubricant, accum... Under spinning conditions, lubricant on islandic spot patterned M2 steel disc experiences centrifugal and tangential force components. Depending upon the relative position of the spots and the flow of lubricant, accumulation of lubricant in front of patterned islandic spots creates thrusting to mating part and subsequently reduces contact between the mating couple. Whilst wear debris is likely to be spun off the plateau of the spots to their neighbouring valleys so as to reduce wear. Hence, it gives favorable tribological characteristics. Aiming at verifying such mechanisms, studies were performed on M2 steel disc specimens slid with ASSAB 17 tool steel pin. The M2 steel disc specimens were respectively (i) machined with non-patterned (NP), (ii) etched to produce in-lined (INE) islandic patterns, and (iii) etched to produce staggered (STE) islandic spot patterns. Results indicated that the INE patterned discs gave most favorable wear characteristics, the NP of the worse characteristics whilst the STE ranged in the middle. However, the actual contact mechanism leads to the descending sequence of favorable friction behaviors nominally as: NP, INE and STE. 展开更多
关键词 dry and wet lubrication friction and wear circular islandic spot patterns M2 steel disc ASSABI7 steel pin
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Wet flue gas desulfurization performance of 330 MW coal-fired power unit based on computational fluid dynamics region identification of flow pattern and transfer process 被引量:1
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作者 Jiangyuan Qu Nana Qi +2 位作者 Kai Zhang Lifeng Li PengchengWang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2021年第1期13-26,共14页
Wet Flue Gas Desulfurization(WFGD)unit based upon spray scrubber has beenwidely employed to control SO_(2) emissions from flue gas in coal-fired power plant.To clarify the dependence of desulfurization performance on ... Wet Flue Gas Desulfurization(WFGD)unit based upon spray scrubber has beenwidely employed to control SO_(2) emissions from flue gas in coal-fired power plant.To clarify the dependence of desulfurization performance on inter-phase transfer behaviors with non-ideal contacting patterns of flue gas and slurry droplets,three regions in spray scrubber are distinguished in terms of gas-slurry flow structures using CFD method in the Eulerian-Lagrangian framework.A comprehensive model is established by involving the transfer process between two phases and chemical reactions in aqueous phase,which is validatedwith the measured data froma WFGD scrubber of 330 MW coal-fired power unit.Numerical results show that the overall uniformity degree of flue gas in whole scrubber is largely determined by the force-balanced droplets in the middle part of scrubber,which is dominated by counter-current mode.Both momentum transfer behavior and SO_(2) chemical absorption process present the synchronicity with the evolution of gas-slurry flow pattern,whilst the heat transfer together with H_(2)O evaporation has little effect on overall absorption process.Three regions are firstly defined as Gas Inlet Region(GIR),Dominant Absorption Region(DAR)and Slurry Dispersed Region(SDR)from the bottom to top of scrubber.SO_(2) is mainly scrubbed in DAR,which provides much more intensive interaction between two phases compared to GIR or SDR.A better understanding of the desulfurization process is obtained from the fundamental relationship between transport phenomena and chemical reactions based upon the complicated hydrodynamics of gas-slurry two-phase flow,which should be useful for designing and optimizing the scrubber in coal-fired power unit. 展开更多
关键词 wet flue gas desulfurization Gas-liquid flow Eulerian-Lagrangian model Flow pattern Transport processes ABSORPTION
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新疆特殊地域环境对冠心病中医证候特点的影响
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作者 范济瑞 李鹏 +2 位作者 范辉 李超 周靖雅 《西部中医药》 2024年第4期50-53,共4页
从新疆特殊地域环境、气候入手,探讨新疆特殊地域环境对高发心血管疾病冠心病中医证候特点的影响,认为新疆特殊地域环境气候下形成的特殊病证——西北燥证,是影响新疆地区心血管疾病的重要危险因素。该证型以感受燥邪为主要病因,兼有痰... 从新疆特殊地域环境、气候入手,探讨新疆特殊地域环境对高发心血管疾病冠心病中医证候特点的影响,认为新疆特殊地域环境气候下形成的特殊病证——西北燥证,是影响新疆地区心血管疾病的重要危险因素。该证型以感受燥邪为主要病因,兼有痰、瘀,表现为本虚标实,故治疗时应当扶正祛邪,具体临证,不囿常法,对新疆地区高发心血管疾病冠心病的中医药防治具有指导意义。 展开更多
关键词 冠心病 心血管 中医证候 西北燥证
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干湿料饲喂方式下商品猪生产和健康指标模型构建与比较
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作者 唐明凤 孙彬 +3 位作者 胡彬 王浩 蒲施桦 龙定彪 《华南农业大学学报》 CAS CSCD 北大核心 2024年第5期694-701,共8页
【目的】精准饲养是当前生猪养殖产业的大趋势,但在实际应用中存在缺乏前期基础数据、各阶段湿料饲喂的采食量不明确等问题。本研究旨在探究干湿料饲喂猪只的生长发育规律、采食量动态模型和健康情况。【方法】选取132头平均初始体质量... 【目的】精准饲养是当前生猪养殖产业的大趋势,但在实际应用中存在缺乏前期基础数据、各阶段湿料饲喂的采食量不明确等问题。本研究旨在探究干湿料饲喂猪只的生长发育规律、采食量动态模型和健康情况。【方法】选取132头平均初始体质量为(10.56±1.21)kg的商品猪,随机分为2组,每组11次重复,每次重复6头猪,2组分别饲喂干料和湿料,试验周期为120 d。通过Logistic、Gompertz和Von Bertalanffy 3种模型分析拟合干湿料饲喂猪只的生长曲线和采食量动态模型,并对干湿料饲喂猪只的健康情况进行研究。【结果】Von Bertalanffy模型拟合干料饲喂猪只生长曲线的效果最好,拟合度为0.999;Gomperz模型能更好地拟合湿料饲喂猪只的生长曲线,拟合度为0.999。Gomperz模型拟合干料饲喂猪只采食量模型的效果最好,拟合度为0.851;Von Bertalanffy模型能更好地拟合湿料饲喂猪只的采食量模型,拟合度为0.988。湿料饲喂保育仔猪的腹泻率和腹泻指数显著低于干料饲喂(P<0.05)。【结论】本研究构建了干湿料饲喂猪只的生长曲线和采食量模型,拟合效果较好;探明了干湿饲喂猪只的健康情况,为猪只的精准饲养提供了数据支撑。 展开更多
关键词 干料 湿料 生长发育规律 生长曲线 采食量 动态模型 精准饲养
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“新八髎”针刺联合督脉刺络放血拔罐治疗慢性荨麻疹的临床研究
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作者 胡晔 李钰 +1 位作者 王钏 周利 《针灸临床杂志》 2024年第8期17-21,共5页
目的:探究“新八髎”针刺联合督脉刺络放血拔罐治疗慢性荨麻疹的临床研究。方法:将2021年1月—2022年6月期间就诊的血虚风燥型慢性荨麻疹患者随机分为观察组和对照组,各60例。对照组接受督脉刺络放血拔罐治疗,观察组接受“新八髎”针刺... 目的:探究“新八髎”针刺联合督脉刺络放血拔罐治疗慢性荨麻疹的临床研究。方法:将2021年1月—2022年6月期间就诊的血虚风燥型慢性荨麻疹患者随机分为观察组和对照组,各60例。对照组接受督脉刺络放血拔罐治疗,观察组接受“新八髎”针刺联合督脉刺络放血拔罐治疗,均连续治疗3个月。比较两组临床疗效和治疗后12个月时的复发情况,比较治疗前和治疗后12个月时的中医症候积分、荨麻疹控制情况[荨麻疹控制评分(UCT)]、炎症因子水平和生活质量[中国版慢性荨麻疹生活质量问卷(CU-Q2oL)]评分。结果:观察组的总有效率显著高于对照组(P<0.05),观察组的复发率显著低于对照组,差异具有统计学意义(P<0.05)。治疗后12个月时,两组患者的中医症候积分、CRP、IL-4、IL-17和CU-Q2oL评分较治疗前显著降低,且观察组低于同期对照组,差异有统计学意义(P<0.05);两组患者的UCT评分较治疗前显著提高,且观察组高于同期对照组,差异有统计学意义(P<0.05)。结论:“新八髎”针刺联合督脉刺络放血拔罐治疗血虚风燥型慢性荨麻疹具有显著的疗效,可以有效缓解症状,降低患者体内炎症因子的水平,显著改善患者的生活质量,有效避免复发情况。 展开更多
关键词 慢性荨麻疹 血虚风燥型 新八髎 针刺 督脉 刺络放血
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基于Copula函数的西江干流与粤西沿海诸小河径流丰枯遭遇分析
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作者 刘成 周秋红 +1 位作者 王占海 吴绍飞 《水电能源科学》 北大核心 2024年第9期11-16,共6页
环北部湾广东水资源配置工程从西江干流取水至广东省粤西地区,为从根本上缓解粤西地区缺水问题,研究西江干流与粤西沿海诸小河径流丰枯遭遇对工程水资源优化配置及运行调度具有重要意义。为此,基于西江干流控制水文站梧州站与粤西二个... 环北部湾广东水资源配置工程从西江干流取水至广东省粤西地区,为从根本上缓解粤西地区缺水问题,研究西江干流与粤西沿海诸小河径流丰枯遭遇对工程水资源优化配置及运行调度具有重要意义。为此,基于西江干流控制水文站梧州站与粤西二个小河控制站,即鉴江化州站及九洲江缸瓦窑站数据资料,采用Copula函数建立了年、枯期、汛期不同时间尺度的径流联合分布函数,分析了径流丰枯遭遇规律。结果表明,西江干流与粤西诸小河径流间具有较高的互补性,建设水资源配置工程可很好地缓解粤西地区的缺水问题。 展开更多
关键词 环北部湾 COPULA函数 西江 粤西沿海诸小河 丰枯遭遇
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The Peat-Organic-Soil in the Hula Valley
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作者 Moshe Gophen 《Open Journal of Ecology》 2024年第4期331-342,共12页
The main soil type, principle contributor of nutrients and available agricultural land in the Hula Valley is the organic Peat. Nevertheless, the relative contribution of Phosphorus from the Hula Valley to the Lake Kin... The main soil type, principle contributor of nutrients and available agricultural land in the Hula Valley is the organic Peat. Nevertheless, the relative contribution of Phosphorus from the Hula Valley to the Lake Kinneret inputs is lower than regional outsourcing. The Nitrogenic matter, mostly Nitrate migration from the Peat soil is significant. The implementation of efficient development is the key factor of Hula Land use. The financial beneficial success of the Hula land use is therefore dependent of Peat soil properties. The porosity of the Peat Soil is high and preferential pathway volume is low and Hydraulic Conductivity is therefore low. Consequently, the Mobile Spray Irrigation line was found as most suitable for cultivation in Peat Soil. Enhancement of Summer irrigation creating moisture elevation reduces Phosphorus migration from Peat Soil and is therefore recommended and recently implemented. 展开更多
关键词 PEAT wetTING dryness ALTERNATE Hula Kinneret
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基于多源数据的黄河源区降雪比变化及其影响因素
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作者 宋怡铭 徐世琴 +1 位作者 余钟波 董宁澎 《冰川冻土》 CSCD 2024年第4期1169-1183,共15页
黄河源区是黄河流域关键产流区域,对气候变化十分敏感。在气候变暖背景下,降水形态转变及其影响因素的研究依然不足。围绕这一重要科学问题,本研究基于地面气象站点观测和多源高分辨率气象数据集[China Meteorological Forcing Dataset(... 黄河源区是黄河流域关键产流区域,对气候变化十分敏感。在气候变暖背景下,降水形态转变及其影响因素的研究依然不足。围绕这一重要科学问题,本研究基于地面气象站点观测和多源高分辨率气象数据集[China Meteorological Forcing Dataset(CMFD)、ECWMF ERA5-Land(ERA5-Land)、Multi-Source Weather(MSWX)],采用湿球温度参数化模型对1980—2015年黄河源区降水形态进行区分,并对降雪比长期变化趋势及其影响因素进行了综合研究。结果表明,1980—2015年黄河源区降水量整体呈增加趋势,降水形态向降雨转变,降雪量减少,平均降雪比呈显著下降趋势(P<0.05),四套数据源的降雪比平均下降速率为0.002 a^(-1)(P<0.05)。降雪比呈显著下降趋势(P<0.05)的格点占比分别为98.31%(ERA5-Land)、96.87%(MSWX)、67.62%(CMFD)。黄河源区中西部降雪比下降速率较快,下降速率最大的地区为玛多、达日等地。三套格点产品中CMFD能够较好地呈现降雪比变化趋势的空间差异,MSWX次之,而ERA5-Land降雪比变化趋势空间变异较小。源区降雪比与年平均气温、降水量相关性较高(P<0.05),相关系数r分别为-0.42和-0.48,亦受到西风的影响(r=-0.31,P=0.07)。研究结果有助于加深气候变暖对黄河源区水文气象过程影响的科学认识,为黄河流域区域水资源管理提供理论支撑。 展开更多
关键词 黄河源区 降水形态 湿球温度参数化模型 降雪比 气候变化
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龙羊峡水库蓄丰补枯特征研究
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作者 席海潮 解阳阳 +3 位作者 刘赛艳 黄成剑 张钦 胡华清 《水文》 CSCD 北大核心 2024年第3期47-51,81,共6页
丰、枯水期末蓄水量是影响多年调节水库蓄丰补枯规则的关键要素。以黄河上游龙羊峡水库为研究对象,基于该水库的历史运行资料,考虑水库丰、枯水期的来水量、初始蓄水量等影响,采用多元线性回归方程建立调度函数,推求丰、枯水期水库增补... 丰、枯水期末蓄水量是影响多年调节水库蓄丰补枯规则的关键要素。以黄河上游龙羊峡水库为研究对象,基于该水库的历史运行资料,考虑水库丰、枯水期的来水量、初始蓄水量等影响,采用多元线性回归方程建立调度函数,推求丰、枯水期水库增补水量,确定水库的丰、枯水期末蓄水量。结果表明:(1)龙羊峡水库丰水期增水量的距平值与来水量的距平值呈显著的正相关性(R^(2)=0.42),枯水期水库补水量的距平值与初始蓄水量的距平值呈显著的正相关性(R^(2)=0.16);(2)由调度函数推求的丰水期增水量与实际增水量的相关性良好(R^(2)=0.62),枯水期补水量与实际补水量相关性也较好(R^(2)=0.38)。研究成果可为龙羊峡水库调度规则的建立提供依据,也可为其他多年调节水库的调度提供参考。 展开更多
关键词 蓄丰补枯 多元线性回归 相关分析 多年调节 龙羊峡水库
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肝系疾病发生与患者出生日期五运六气特点相关性分析
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作者 徐梓桥 吴艺锋 黄腊平 《广州中医药大学学报》 CAS 2024年第3期555-561,共7页
【目的】探讨肝系疾病患者出生日期的五运六气特点,分析肝系疾病发生与患者出生日期五运六气特点的关联性。【方法】收集广东省中西医结合医院2021年5月至2023年5月收治的肝系疾病患者的住院病例共5057例,统计分析患者出生日期的五运六... 【目的】探讨肝系疾病患者出生日期的五运六气特点,分析肝系疾病发生与患者出生日期五运六气特点的关联性。【方法】收集广东省中西医结合医院2021年5月至2023年5月收治的肝系疾病患者的住院病例共5057例,统计分析患者出生日期的五运六气特点。【结果】肝系疾病患者发病与主运、主气、客气、客主加临、运气相合密切相关;主运中,金运时期出生者患病率最高,火运最低;主气中,太阴湿土时段出生者患病率最高,太阳寒水时段出生者患病率最低;客气中,阳明燥金时段出生者患病率最高,少阴君火时段出生者患病率最低;不同客主加临时段中,客气相生或相克主气为顺关系时段出生者患病率最高,主气与客气为同气关系时段出生者患病率最低;在不同运气相合特点的年份中,顺化年出生者患病率最高,岁会年出生者患病率最低,差异均有统计学意义(P<0.05或P<0.001)。【结论】肝系疾病发生与患者出生时的主运、主气、客气、客主加临、运气相合之间存在一定的关联性。 展开更多
关键词 肝系疾病 出生日期 五运六气 金运 太阴湿土 阳明燥金 顺化年
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Latitudinal patterns of climatic variables and influence of local topography on climatic variables in the dry valleys of southwestern China
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作者 LI Xiao-juan LIU Xin +1 位作者 ZHANG Han-yue BAO Wei-kai 《Journal of Mountain Science》 SCIE CSCD 2022年第5期1348-1356,共9页
Climate is a key factor to determine the pattern of ecosystems;however,the latitudinal patterns of climatic variables in the arid and semiarid areas remain largely unclear when compared to humid areas.The topography o... Climate is a key factor to determine the pattern of ecosystems;however,the latitudinal patterns of climatic variables in the arid and semiarid areas remain largely unclear when compared to humid areas.The topography of the dry valleys of southwestern China plays an important role in the formation of climate.However,its impact on the climate remains qualitative.In this study,eight climatic variables from 12 meteorological stations were analyzed to explore their latitudinal patterns in the wet and dry seasons from 1961 to 2019.We also quantified the effects of local topography(RH10)on the climatic variables.The results were as follows:sunshine duration,total solar radiation,average temperature,and evaporation decreased significantly,and wind speed increased significantly with increasing latitude in the annual,wet,and dry seasons(P<0.001).Relative humidity and precipitation decreased significantly with increasing latitude in the wet season(P<0.001),and no obvious change pattern was observed in the dry season.Aridity index significantly decreased(toward dryness)with increasing latitude in the wet season and increased in the dry season(P<0.001).Wind speed had a significantly positive relationship with topography(RH10)(P<0.01),whereas precipitation and aridity index were negatively associated with topography in the wet season and positively associated with topography in the dry season.Dryness was positively associated with RH10 in the wet season,and negatively in the dry season.The results of our research could provide new perspectives for understanding the relationship between topography and drought in the dry valleys of southwestern China. 展开更多
关键词 Latitudinal patterns wet season Dry season Aridity index Local topography
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Statistical Prediction of Wet and Dry Periods in theComahue Region (Argentina)
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作者 Marcela H. González Diana Dominguez 《Atmospheric and Climate Sciences》 2012年第1期23-31,共9页
General features of rainy season with excess or deficits are analyzed using standardized precipitation index (SPI) in Limay and Neuquen River basins. Results indicate that most of dry and wet periods persist less than... General features of rainy season with excess or deficits are analyzed using standardized precipitation index (SPI) in Limay and Neuquen River basins. Results indicate that most of dry and wet periods persist less than three months in both basins. Furthermore, an increase of rainfall variability over time is observed in the Limay river basin but it is not detected in the Neuquen river basin. There is a tendency for wet (dry) periods to take place in El Ni?o (La Ni?a) years in both basins. Rainfall in both basins, have an important annual cycle with its maximum in winter. In addition, possible causes of extreme rainy seasons over the Limay River Basin are detailed. The main result is that the behavior of low level precipitation systems displacing over the Pacific Ocean in April influences the general hydric situation during the whole rainy season. In order to establish the existence of previous circulation patterns associated with interannual SPI variability, the composite fields of wet and dry years are compared. The result is that rainfall is related to El Ni?o- Southern Oscillation (ENSO) phenomenon and circulation over the Pacific Ocean. The prediction scheme, using multiple linear regressions, showed that 46% of the SPI variance can be explained by this model. The scheme was validated by using a cross-validation method, and significant correlations are detected between observed and forecast SPI. A polynomial model is used and it little improved the linear one, explaining the 49% of the SPI variance. The analysis shows that circulation indicators are useful to predict winter rainfall behavior. 展开更多
关键词 Precipitation South AMERICA wet and Dry PERIODS CIRCULATION patterns Sea Surface Temperature
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加味白疕方湿包疗法联合阿维A胶囊治疗风热血燥型银屑病 被引量:1
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作者 孟阳 张蓉 蒋琼 《长春中医药大学学报》 2023年第4期426-429,共4页
目的观察加味白疕方湿包疗法联合阿维A胶囊治疗风热血燥型银屑病的疗效。方法将60例风热血燥型银屑病患者采用随机数表法分为对照组与观察组,各30例。对照组予阿维A胶囊治疗,观察组在对照组基础上联合加味白疕方湿包疗法治疗,观察2组临... 目的观察加味白疕方湿包疗法联合阿维A胶囊治疗风热血燥型银屑病的疗效。方法将60例风热血燥型银屑病患者采用随机数表法分为对照组与观察组,各30例。对照组予阿维A胶囊治疗,观察组在对照组基础上联合加味白疕方湿包疗法治疗,观察2组临床治疗效果。结果治疗后观察组临床总有效率(93.33%,28/30)高于对照组(66.67%,20/30)(P<0.05);治疗后,2组银屑病面积和严重程度指数(PASI)评分、瘙痒程度视觉模拟(VAS)评分、皮肤病生活质量指数(DLQI)评分和白细胞介素-17(IL-17)、白细胞介素-22(IL-22)均下降,且观察组低于对照组(P<0.05);治疗后,2组角质层含水量、角质层油脂含量均升高,且观察组高于对照组(P<0.05)。结论加味白疕方湿包疗法联合阿维A胶囊治疗风热血燥型银屑病患者,可促进症状改善,降低疼痛瘙痒程度,提高生活质量水平,改善皮肤屏障功能,降低IL-17、IL-22等炎症因子表达。 展开更多
关键词 银屑病 风热血燥型 加味白疕方湿包疗法 阿维A胶囊 临床疗效 症状评分 炎症因子
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基于三维Copula函数的滦河流域干支流丰枯遭遇研究 被引量:1
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作者 魏琳 杨学军 王旭东 《海河水利》 2023年第1期87-91,99,共6页
滦河流域主要产流区位于中游,考虑流域上下游来水量、干支流的相依关系,应用三维Copula函数,开展主要产流区滦河干流、潵河支流、青龙河支流年来水量的联合概率分布及条件概率分布对滦河流域干支流丰枯遭遇的分析研究,为洪水资源利用、... 滦河流域主要产流区位于中游,考虑流域上下游来水量、干支流的相依关系,应用三维Copula函数,开展主要产流区滦河干流、潵河支流、青龙河支流年来水量的联合概率分布及条件概率分布对滦河流域干支流丰枯遭遇的分析研究,为洪水资源利用、合理优化防洪调度提供参考依据。以该流域1956—2016年来水量系列开展建模分析,对各区间来水量系列采用拟合优度检验,边缘分布选择4种常用的分布线型,采用4种拟合准则,综合开展最优线型选择,经分析计算可知3个区间来水量均以P-Ⅲ型分布为最优;Copula函数采用均方根误差进行拟合优度检验,选取Frank Copula函数拟合效果最好。根据所建模型,可得到不同条件组合下来水量的条件概率,滦河干流、潵河、青龙河同时出现枯水年的概率为13%。Copula函数为研究多维联合概率分布及丰枯遭遇提供了新的有效手段。 展开更多
关键词 丰枯遭遇 联合概率分布 三维Copula函数 拟合优度 流域
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基于圆筒入渗仪的田间膜孔灌土壤入渗参数研究
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作者 范严伟 唐兴鹏 +1 位作者 史金红 马天花 《农业机械学报》 EI CAS CSCD 北大核心 2023年第2期302-310,367,共10页
了解膜孔灌形成的土壤湿润体尺寸对于设计经济高效的灌溉系统至关重要。采用HYDRUS-2D/3D数值模拟方法,研究土壤容重和膜孔直径对12种质地土壤入渗特性的影响。基于180组数值模拟结果,对湿润体运移模型的参数进行了优化。采用田间圆筒... 了解膜孔灌形成的土壤湿润体尺寸对于设计经济高效的灌溉系统至关重要。采用HYDRUS-2D/3D数值模拟方法,研究土壤容重和膜孔直径对12种质地土壤入渗特性的影响。基于180组数值模拟结果,对湿润体运移模型的参数进行了优化。采用田间圆筒入渗仪试验和室内土箱试验(文献资料)对模型的可靠性进行评价。结果表明:湿润半径和湿润深度均随膜孔直径和灌溉时间的增大而增大,而随土壤容重的增大而减小;两者与稳渗率和灌溉时间呈幂函数关系,建立一种适用于不同土壤质地类型的湿润体运移模型;对于特定土壤质地,稳渗率与土壤容重和膜孔直径之间具有良好的幂函数关系,幂函数指数分别为-6.3和1.1,幂函数系数只需1组圆筒入渗仪田间试验即可推求。所建模型计算值与12组试验实测值一致性较好,均方根误差接近于0(介于0.020~0.170 cm之间),纳什效率系数趋近于1(介于0.995~0.999之间),实现了膜孔灌湿润体尺寸模型在田间的实际应用,试验设计简单,方便管理人员进行快速的现场评估。 展开更多
关键词 膜孔灌 圆筒入渗仪 湿润体尺寸 稳渗率 入渗参数
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液相下激光烧蚀快速制备图案化铜微纳结构 被引量:1
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作者 于苗苗 翁占坤 +3 位作者 王冠群 郭川川 胡俊廷 王作斌 《光学精密工程》 EI CAS CSCD 北大核心 2023年第15期2248-2259,共12页
为了实现大面积图案化铜微纳结构的制备,基于液相下激光烧蚀技术,以硅片为衬底,将其浸没在含有Cu2O微米粒子的乙醇溶液中,采用纳秒脉冲激光进行加工。研究了激光功率、扫描速度和扫描次数对铜微纳结构的影响,分析了图案化铜微纳结构的... 为了实现大面积图案化铜微纳结构的制备,基于液相下激光烧蚀技术,以硅片为衬底,将其浸没在含有Cu2O微米粒子的乙醇溶液中,采用纳秒脉冲激光进行加工。研究了激光功率、扫描速度和扫描次数对铜微纳结构的影响,分析了图案化铜微纳结构的形成机制,并研究了图案化铜微纳结构的浸润特性。扫描电子显微镜结果表明,随着激光功率、扫描速度和扫描次数的增加,图案化铜微纳结构中的铜颗粒熔融现象加剧,光斑中心区域的纳米颗粒粒径逐渐增大,光斑交界处形成呈现周期性分布的微米量级单元结构。能量色散X射线光谱证明少量Cu元素分布在光斑中心区域,大量Cu元素集中在光斑交界处。随着扫描次数的增加,样品表面粗糙度和纯净水/食用油接触角均呈现先上升后下降的趋势。当扫描次数为6时,表面平均粗糙度为(1.3±0.11)μm,纯净水接触角可达(155.2±1.5)°,食用油接触角达(100.0±1.3)°。该大面积图案化铜微纳结构制备方法简单快速,无粉尘污染,在微流体芯片、集水系统和废水处理等领域具有广泛的应用前景。 展开更多
关键词 激光烧蚀 图案化铜微纳结构 浸润特性 二元结构
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