近49年来塔城盆地霜冻特征分析

利用塔城盆地1961～2009年霜冻观测资料,采用气候统计学方法,对塔城盆地四县市初、终霜日、无霜期气候特征及其气候变化进行分析.结果表明,塔城盆地终霜日随着年代的增加而逐渐偏早,初霜日随时间的推迟而逐渐推迟,无霜期呈明显的增加;进入90年代以来,初、终霜日、无霜期的标准差均比前30年有明显的增加,说明塔城盆地的初霜日、终霜日年际变化有增大的趋势.地理位置对无霜期的变化有很大影响,其标准差是随海拔高度的增加而变大的.     

山东省霜冻的气候变化特征分析

[目的]研究山东省霜冻的气候变化特征.[方法]以秋季或春季日最低地面温度≤0℃作为霜冻指标,利用1961～2008年山东省67个气象监测站的逐日地面最低温度资料,采用气候诊断分析方法,对山东省初、终霜日期和无霜期的变化特征进行了分析.[结果]近48年来,山东省的初、终霜日和无霜期的气候特征具有明显地域差异.初、终霜日和无霜期的极差均为标准差的3倍以上,说明初、终霜日和无霜期离散程度均较大.近48年山东省平均初霜日以1.99 d/10a的速率推迟,终霜日以1.46d/10a的速率提早,初霜日推迟幅度比终霜日提早幅度大;无霜期以3.42 d/10a的速率延长.从年代际变化来看,初霜日20世纪90年代以后开始明显推迟,终霜日90年代之后明显提早,无霜期是90年代开始明显延长.[结论]该研究为霜冻灾害的预测预防和农作物结构调整提供一定的参考.     

邢台地区近50年初终霜日及无霜期变化分析

采用气候统计学方法,对邢台地区1961～2010年初、终霜日及无霜期气候特征进行了分析.结果表明,初霜日平均值为10月22日,时间序列绝对变率为4.68 d,线性趋势为0.76 d/10 a,呈逐渐推迟趋势;终霜日平均值为3月27日,时间序列绝对变率为8.35 d,线性趋势为-0.29 d/10 a,呈逐渐提前趋势;而无霜期平均值为209 d,绝对变率为8.12 d,线性趋势为1.10 d/10 a,呈平稳增长趋势.初霜日、终霜日及无霜期的稳定变化趋势,对于霜冻预报具有重要的参考价值和指导作用.     

近50年建昌县霜期设施农业生产中光热气候资源变化特征

[目的]研究近50年建昌县霜期设施农业生产中光热气候资源变化特征.[方法]利用近50年建昌县气候资料,采用常规数理统计方法,分析了1960～2009年建昌县霜期光照、气温变化趋势.[结果]1960～2009年建昌县霜期日照时数、日照百分率呈减少趋势,气候倾向率分别为-55.556 h/10 a、-2.39%/10 a,近50年分别减少了278 h和12%;1981、1982年发生了气候跃变,跃变前后日照时数、日照百分率分别减少161 h和7%.霜期气温总体呈升高趋势,平均气温、平均最高、最低气温气候倾向率分别为0.386、0.392和0.567℃/10 a.近50年分别上升了1.93、1.96和2.84℃;1987、1988年发生气温跃变,跃变前后霜期平均气温、平均最高、最低气温分别升高了1.3、1.2和1.7℃.近50年来,建昌霜期光照资源减少,而热量资源增加,形成光热互补.[结论]该研究为当地霜期设施农业的发展提供了气候依据.     

辽宁省建昌地区春播期水热资源气候特征分析

采用气候倾向率、春旱指数等方法,分析了建昌春播期降水和气温的变化特征.结果表明,近50年(1960～2009年)建昌春播期热量资源在增加,平均气温趋势升高1.25℃;1990～2009年较1961～1980年平均气温升高1.00℃;气温稳定通过≥10℃初日变化稳定;终霜日期趋势提前4 d结束,变化幅度由31 d缩短至19 d,趋于稳定.降水量存在增加趋势,降水量变率过大对春播及苗期生长不利;春旱频率较大影响春季播种;重旱、偏旱年有30年,占60%;近20年(1990～2009年)重春旱频率较之前略有增加.适宜播种期在4月15～20日.     

重庆主城区百年雨日及强度变化特征

利用重庆主城区近百余年降水资料,研究了不同级别雨目及其强度、贡献率的气候特征和长期变化趋势,并探讨了它们与各年代降水异常的关系.结果表明:重庆主城区降水日数近百余年为显著的线性增加趋势,而1961年以来却为显著的线性减少趋势.百年来降水日数的阶段变化十分明显,分为增→降→增→降4个阶段,其中20世纪60年代降水日数最多,20世纪20年代最少.小雨日数与降水日数的变化趋势比较一致.中雨、大雨和暴雨的线性趋势不明显,分别为弱的减、增、增趋势.降水强度阶段变化正好与降水日数相反.降水量异常与各级雨日日数、强度和贡献率密切相关.年降水最少的年代1892-1900年主要与大雨和暴雨日数显著偏少、暴雨强度偏弱有关.年降水最多的是20世纪10年代,主要是暴雨日数偏多引起暴雨的贡献率显著偏高.21世纪以来降水偏多主要与中雨日数偏多和暴雨强度偏强有关.     

区域暴雨指标与作物洪涝受灾率的关系

利用北京地区1985～2008年逐日降水数据资料,运用IPCC极端天气气候事件指标确定方法计算得到北京地区暴雨天气指标在10.4～38.8mm波动,暴雨气候指标为日降水量≥27.5mm.以暴雨天气指标、暴雨气候指标和国家暴雨标准计算历年的暴雨日数和暴雨量,统计分析年降雨日数、暴雨日数和年降水量和暴雨量与作物洪涝受灾率的相关关系,得出年降雨日数和暴雨日数都不能真实地反映作物洪涝受灾率,而年降水量和暴雨量与作物洪涝受灾率则具有明显的线性正相关关系.以区域暴雨气候指标统计的暴雨量与作物洪涝受灾率相关程度最高,建议以暴雨量来预测评估洪涝灾害时,采用区城暴雨气候指标.     

全国工业炉学会第九届燃料炉、第二届热仿真与控制学术交流会在皖召开

正由中国机械工程学会工业炉分会燃料炉委员会、热仿真与控制委员会主办,安徽工业大学、工业炉杂志社协办的第九届燃料炉、第二届热仿真与控制学术交流会于2014年7月10日至13日在安徽省马鞍山市安徽工业大学召开。美丽的安徽工业大学绿树成荫,鲜花盛开,迎接着来自全国各地的90余名参会代表。开幕式由燃料炉主任委员解文书教授级高工主持。安徽工业大学副校长魏先文教授首先致欢迎辞并向     

辽宁西部朝阳农村气温和热量资源变化分析

[目的]研究辽西朝阳农村的气温和热量资源变化特征.[方法]选取1966～2010年辽西朝阳农村气象站资料,应用序列相关和气候倾向率等统计方法,对朝阳农村的气温和热量资源变化特征进行分析,掌握该农村的气候现状.[结果]1966～2010年辽西朝阳农村日平均气温、日最高气温和日最低气温的年均值呈波动变化,其中日最高气温年均值趋势升高增温幅度最大(0.328℃/10a),且显著水平最高,是气温升高的主体;日平均气温增幅(0.151℃/10a)和显著水平次之;日最低气温呈下降趋势,且显著水平不明显.在冬、夏半年时间尺度里,日最高气温平均值趋势升高明显,气候倾向率分别为0.417和0.250℃/10a,以冬半年升高最突出;日平均气温趋势性显著水平较低,日平均最低气温趋势性不显著.辽西朝阳农村≥10℃积温呈波动增加趋势明显,气候倾向率为42.590(℃·d)/10a,近45年趋势增加192(℃·d).[结论]该研究为调整农业结构和品种布局等农业措施提供气候依据.     

晋城市雷电时空分布特征分析

使用晋城地区5个气象台站1979～2009年的雷暴观测资料,统计分析了晋城地区雷电的初日、终日,雷电日的年、月分布及时间变化趋势,雷电的空间分布及变化等气候变化特征.结果表明,雷电日数以短周期变化为主,存在3～5年的周期振动,总体有增多的趋势.晋城地区除冬季未观测到雷电现象外,春季、夏季、秋季均有雷电发生.晋城市雷电日空间分布的变化较为明显.     

跨越时空的罗伯特·弗洛斯特

自1913年罗伯特·弗洛斯特的第一部诗集出版并获得成功以来,他的诗为全世界所传诵.在此,将罗伯特·弗洛斯特的两首代表作置于现代意境中重新加以诠释,从中感受作品不同凡响而寓意深刻的现实意义.     

Practical Model of Frost Heave in Clay

Freezing behavior of clay differs from that of silt. This difference stems primarily from the low permeability or hydraulic conductivity of clay, and the higher water content of saturated clay. Freezing effects include simultaneous heave and consolidation. Six small physical model columns of clay were frozen: one at 1g; and five on a centrifuge at various scales and with corresponding accelerations, to bring self-weight stresses into similarity with a full scale column of clay 4?m in height. The experimental results demonstrated the importance of replicating the prototype stress conditions in a model. They demonstrated the importance of local water content on development of heave in clay, and the relative insensitivity of heave to location of the phreatic surface. Low permeability caused the clay to behave essentially as a closed system with regard to water flow. A simple analytical model was developed to explain observed soil response. Further research is recommended to provide more guidance in selecting input parameters.     

Assessing Frost Resistance of Concrete Aggregates in Minnesota

This study was undertaken to identify test procedures capable of reliably assessing concrete aggregate freeze-thaw durability and establish appropriate acceptance criteria for the same. Highway condition surveys were performed to document the field freeze-thaw performance of selected aggregate sources representing a range of frost resistance. Cores were obtained for laboratory testing and evaluation, and samples of the original aggregate sources were obtained for use in performing environmental simulation tests [i.e., variations of ASTM C 666 and the Virginia Polytechnic Institute (VPI) single-cycle slow-freeze test] and correlative tests (e.g., absorption capacity, Iowa pore index test, X-ray diffraction and fluorescence analysis, and hydraulic fracture test). Petrographic examination was used to correlate aggregate geological and engineering properties with the results of environmental and correlative tests. A suite of tests was developed for more accurately assessing the probable field performance of any given aggregate as a function of its original geological origin and probable environmental exposure. Petrographic examination is used first to identify aggregate composition and provide a basis for selecting subsequent durability tests, which may include the hydraulic fracture test, VPI single-cycle slow-freeze test, and ASTM C 666 Procedure B (modified to use salt-treated aggregates).     

Improvements in Frost Heave Laboratory Testing of Fine-Grained Soils

We present a laboratory system designed for studying frost heave in fine-grained soil. The system consists of: a modified refrigerator, a frost heave test cell, a laser for measuring heave, a differential pressure transducer for measuring water intake, and platinum resistance temperature detectors for measuring pedestal temperatures. The frost heave cell allows for visual observation of the sample, and accommodates pretest sample consolidation, freezing tests using a variety of freezing methods, triaxial tests on frozen soil, and thaw consolidation tests. The modified refrigerator maintains the specified temperature ±0.5°C during the full length of the test. Test results indicate repeatability of frost heave ratios ξ to within ±7%, and average heave rates to within ±0.05?mm/h. Results from frost heave tests conducted on five fine-grained soils indicate that: (1) a soil removed of its colloidal organic content becomes less frost susceptible; (2) the geomorphologic history of a “regional” soil is a critical factor influencing its frost susceptibility; and (3) ξ is dependent on overall clay content and is most sensitive to chlorite content.     

Carl Frost (1914–2009).

Presents an obituary for Carl Frost. Carl Frost, professor emeritus at Michigan State University (MSU), died June 20, 2009, in Holland, Michigan, at the age of 94. Carl was best known for his organizational development work, in which he fostered the use of Scanlon Plan principles to increase organizational productivity and individual responsibility and satisfaction. He retired from MSU in 1982 but continued his collaboration with various private and public institutions until his death. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Protective Layer Design in Landfill Covers based on Frost Penetration

We develop a design procedure to determine the minimum thickness of a protective soil layer over a barrier layer in a landfill cover design. The procedure equates the minimum thickness of the overlying protective layer to the predicted extreme freezing-events depth that may occur in the landfill design life. This procedure is applicable to Resource Conservation and Recovery Act Subtitle C hazardous waste landfills and any landfill designed to encapsulate hazardous waste from the environment for long periods of time. This procedure was formulated by the Uranium Mill Tailings Remedial Action Project’s Technical Assistance Contractor to protect radon and infiltration barriers from degradation over a 200-year minimum design life. The procedure uses common soil parameters, a personal computer version of the modified Berggren equation, and site-specific daily maximum-minimum temperature data compiled for a minimum of 30 years to compute frost depths. The computed frost penetration magnitudes are then used with a Gumbel extreme-value probability distribution to predict frost depths for recurrence intervals corresponding to a design life that exceeds the record of observed data.     

一起氩气管道冻裂事故的分析

某制氧厂氩气送出系统因用气量的变化,致使部分液氩进入空温式汽化器后的碳钢管道中,将碳钢管道冻裂;针对冻裂的具体情况,提出了今后的预防措施。