近爆作用下压型钢板组合楼板动力响应及影响因素数值分析

利用有限元软件ANSYS/LS-DYNA,采用流固耦合的计算方法,对压型钢板组合楼板在近爆炸荷载作用下进行了不同工况的数值模拟,得出其受力形态,分析其动力响应及破坏过程,找出影响楼板动力响应的主要因素。数值分析结果表明：适当增加混凝土厚度和提高压型钢板强度,可以显著降低组合楼板的跨中最大位移,提高组合楼板的延性和抗爆性能;组合楼板中钢筋间距的变化,对组合楼板抗爆性能影响较小。     

湖南省森林火灾人为火源时空分布特征

人为火源是引发森林火灾的主要原因,对火源时空分布特征的认识关系到火源管理工作成效,也是实现林火生态预防的重要基础。以湖南省2001-2008年导致森林火灾的生产性火源和非生产性火源数据为例,应用变异系数、基尼系数和集中度3种方法分析湖南省人为火源的区域差异变动情况、空间分布均衡程度及地域分布。结果表明,生产性火源和非生产性火源的差异变动表现出波动上升趋势,3种方法所反映的火源空间分布特征一致。特别是近3年来,非生产性火源的差异变动幅度大,上升趋势极为明显。表明湖南省森林火灾的生产性火源和非生产性火源的区域差异和空间聚集特征明显;森林火灾的发生受自然调节、人为调控作用影响;近年来,区域非生产性火源导致的森林火灾差距有扩大趋势,空间聚集程度加剧,反映出人类社会活动较大程度上影响了森林火灾的发生;湖南省人为火源引发的森林火灾主要集中在邵阳、长沙和永州等地。     

四川省林火的时空分布特征及其气候背景分析

利用四川省遥感监测林火资料、四川省气象资料和MODIS卫星云量资料,分析了四川省林火发生的时空变化特征及其气候背景。结果表明,2—4 月是四川林火的高发季节,高发区域主要位于川西高原的甘孜州南部、凉山州和攀枝花市境内。对四川气温和降水的分析表明,2—4 月上述区域是四川省气温最高、降水最少的区域。此外,这些区域前冬持续少雨干燥的气候特点也有利于2—4 月林火的频发。从5 月开始,随着雨季的到来,林火显著减少。卫星观测的云量表明,这些区域的高温少雨与该地区云量最少有关。由于川西高原气温的日较差大,与平均气温相比,最高气温的空间分布对林火分布更加有指标意义。     

Analysis and Simulation of the Highway Tunnel Fire Contamination

A one-dimensional contamination diffusion model for tunnel fire is presented. Based on this model, a highway tunnel fire within a short time course was simulated and analyzed. Compared to the test results, the simulation result demonstrates that the model is feasible. In the end, it suggests a formula for highway tunnel fire contamination. The author hopes that this analysis will be available as the foundation of highway tunnel fire control.     

控失尿素减施及不同配比对夏玉米产量及氮肥效率的影响

添加纳米矿物类控失剂的控失尿素可通过吸附作用,减少施入土壤后的氮素损失,明确该控失尿素施用量、与常规尿素合理配比在夏玉米上的效应,可为夏玉米一次性施肥、氮肥减施增效提供依据。在不同产量水平(高、中、低产田)土壤上,通过田间试验研究常规尿素(纯氮210 kg hm^–2)、控失尿素常量及减施(减量10%,即纯氮189 kg hm^–2;减量20%,即纯氮168kghm^–2)、控失尿素与常规尿素配施(配比分别为7∶3、5∶5和3∶7)对夏玉米产量、地上部生物量、养分积累量、光合特性及氮肥利用效率的影响。结果表明,氮肥施用可显著提高夏玉米产量,常量控失尿素施用下夏玉米增产率达22.96%～27.55%,在高、中产田上产量较常规尿素有显著提升。与常量控失尿素相比,控失尿素减施10%和20%通过提升穗粒数使得高、中产田夏玉米产量不降低,控失尿素减施20%处理下高产田氮肥利用率高达41.60%。控失尿素与常规尿素7∶3配施下的氮素积累量与常量控失尿素处理无显著差异,高产田和中产田夏玉米产量、秸秆干物重均未显著降低,同时可显著提高低产田夏...     

肉制品加工过程中的有毒有害成分分析

从我国食品安全现状的分析入手,着重关注我国肉制品的安全发展现状及其加工生产过程中有毒有害物质。通过查阅相关资料研究发现:随着肉制品生产工艺和技术的不断发展,使得肉制品质量安全存在一定的隐患,肉制品中有毒有害物质以苯并(a)芘为代表。对肉制品中的有毒有害物质检测方法的分析对比得出:采用高效液相色谱检测苯并(a)芘,具有灵敏度高、分析时间短、分离效率高等优点。     

基于主成分和聚类分析的柳州市森林火灾特征研究

为给柳州市预防森林火灾提供参考依据,根据柳州市2010—2017年的森林火灾资料,采用常规统计方法对柳州市森林火灾的时空动态和分布规律进行研究,利用主成分分析和聚类分析对柳州市森林火灾形势进行评价。结果表明：（1）柳州市森林火灾的发生年际波动显著,2017年林火发生次数最高,其次是2011年和2014年。林火主要集中在秋末、冬季和春初;（2）从空间分布看,森林火灾主要发生在中南部的鹿寨县、柳江区、柳城县,以鹿寨县最为集中,火场总面积及受灾森林面积也最大。（3）在火灾形势方面,按照严重程度将森林火灾分为8类,其中鹿寨县的火灾形势较为严峻,级别波动明显,其次是柳城县的火灾形势呈波动恶化态势。研究结果为建立柳州市森林火险气象等级预报提供了借鉴。     

Dynamics of nitrogen and phosphorus in paddy field under deep application condition of urea pill and its pollution-reducing potential

Dynamics of the pollutants such as nitrogen, phosphorus and the suspended particulates in the field water and soil and its pollution-reducing potential are investigated in the rice plant returning-green stage using deep application technique of urea pill with the application depth of 3, 7 and 11 cm (expressed as t-3, t-7 and t-11, respectively) based on the micro-zone simulation field experiments. Results show that nitrogen content in the field water gradually decreases within 5~7 d after deep allocation of urea, and reaches the low level after the seventh day. NO-3-N concentration is higher than NH+4-N, but there is little difference between treatments. As the pollution source is concerned, NO-3-N in the field water should be considered. There isn’t any correlation between nitrogen content in the water and urea application depth in the field. By contrast with blank treatment（expressed as t-c）, NO-3-N, NH+4-N and TN contents in the field water with deep application of urea pill decrease 29%～47%, 64%~89% and 79%～97%, respectively. The TP and DP are in the high level in the field water with t-3 and t-7. The TP, DP and SS concentration in the field water with t-11 decrease 32%～73%, 92%～99% and 50%～80%, suggesting that deep application of urea pill into 11 cm layer of the field should have a significant pollution-reducing potential and become one of effective measures to control non-point source pollution of agricultural system.     

Fire blight resistance and genetic trueness-to-type of four somaclonal variants from the apple cultivar Greensleeves

Four somaclonal variants regenerated from adventitious buds of the apple variety Greensleeves were preselected on the basis of their reduced fire blight susceptibility. The present study aimed at assessing precisely their level of fire blight resistance through various inoculation techniques (on in vitro leaves and microcuttings, on greenhouse plants and in field conditions). Overall results of these tests indicated that one clone (R 46/3) was clearly less susceptible than the control. This clone was also characterized as a ‘spur’ variant, with a reduced growth which can explain its limited susceptibility to fire blight. A second clone (R 20/63) was slightly less susceptible than the control in greenhouse and field tests, but this low level of resistance was overcome by high concentrations of inoculum. The absence of variation in chromosome number and isozyme patterns confirmed the genetic trueness-to-type of these four somaclones. This revised version was published online in August 2006 with corrections to the Cover Date.     

基于层次模型及权重分析的湖北省雷电灾害易损度区划

利用湖北省2008-2011年闪电监测数据和2000-2009年雷电灾害统计数据,选取雷击大地密度、大于50kA强雷击密度、雷电灾害频度、生命易损模数及经济易损模数作为湖北省雷电灾害易损性评估指标。提出了对雷灾频度因子的修正,只有把该参数放到同一起点比较,雷电灾害易损性分析及风险区划才具科学性,同时引入大于50kA强雷击密度作为雷电灾害易损性评估指标之一。采用层次模型及权重分析对雷电灾害易损性指标划分了5个等级,最后形成湖北省雷电灾害易损度区划。研究结果表明：高风险区的城市主要特征是雷灾频度较高、经济发展水平较好、人口密集;低风险区则与之相反。雷电灾害易损度不仅与单位面积上的雷电密度、雷灾频度关系密切,还与单位面积上的经济发展水平、人口密度息息相关。     

Example Verification and Experimental Study of Network Model for Room Temperature Prediction during the Fire in Buildings

The network model for room temperature and its implicit differential equation are discussed in this paper. The example verification and experimental study were carried out for the prediction of the room temperature in the software of predicting the properties of smoke flow. The results show that the results of example computation are similar to those obtained by similar software in Japan. The results of computation by the software tally with the experimental ones and accord with the law of development and change of room temperature during the fire.     

基于GIS技术的重庆市暴雨洪涝灾害风险区划研究

为了定量地研究分析重庆暴雨洪涝灾害风险和区划,利用重庆1961-2008年的气象观测资料,综合全市各区县的自然、社会经济与防灾抗灾等数据,利用GIS技术和自然灾害风险指数,构建暴雨洪涝灾害风险评价模型,对重庆市暴雨洪涝风险的致灾因子危险性、孕灾环境敏感性、承灾体易损性、防灾抗灾能力多个因子定量分析,计算得到重庆市区县级暴雨洪涝灾害风险综合指数,并绘制了风险区划图。结果表明：重庆的开县、梁平、合川、北碚、荣昌、永川、渝北及铜梁部分地区的危险性和易损性指数较大,其暴雨洪涝灾害风险最大;南川、丰都与石柱、黔江、涪陵、綦江部分地区由于暴雨洪涝发生频率较低,孕灾环境敏感性指数较小,灾害风险最小。     

宜宾市某茶园土壤潜在毒性元素污染评价及源解析

为更好的揭示宜宾市屏山县某茶园土壤PTEs污染现状与来源,通过对研究区样品采集和检测分析,利用内梅罗指数、地积累指数和潜在生态风险指数对茶园土壤中7种潜在毒性元素(PTEs)(Cd、As、Cr、Cu、Pb、Ni和Zn)进行了污染评价,并以多元统计与空间分析相结合的手段对其进行了溯源分析.结果 表明:茶园土壤中7种PTE...     

Selection Theory and Method of Stock Investment Strategy

The author analyzes and concludes the factors that affect the stock market, and gives out the theory basis of the model and its feasibility; Then, based on the related knowledge of statistics and unit exchange, the selection theory and its corresponding model of stock investment strategy are gotten to describe the risk situation of stock market. At last, the author concludes the selection method of stock investment strategy and does the empirical study to prove that the strategy is both right and efficient.     

An analysis on the energy of coal and gas outburst process

Based on the hypothesis of the synthetic coal and gas outburst operating, we study the work done by elastic energy of coal mass and methane expansion energy in the coal and gas outburst process through theory and experiment. By using MTS815 rock mechanics test system, the triaxial compression test of the coal sample is carried out under different confining pressures and the power function relation between coal bodys elastic energy per unit volume and body stress is worked out. It shows there is a linear relation between methane expansion energy and methane pressure obtained by testing methane expansion energy under different moisture contents, different methane pressures and different compactness of coal mass, with the help of self-developed methane expansion energy testing device. The temperature change in the system is about 1 ℃ when methane does work in expansion. The result also shows that it could be regard as an isothermal process during coal and gas outburst. The results from experiment do great help in researching the mechanism of coal and gas outburst and establishing energy criterion.     

中国省域农业产业竞争力评价与分析

将竞争力理论与国情相结合构建中国省域农业竞争力评价指标体系,综合应用因子分析法与德尔菲法确定指标权重,并以全国性的统计年鉴数据为基础对中国大陆地区31个省市的农业产业竞争力进行评价与动态分析。     

Repression of the Interference in the Wigner Distribution and the Algorithm

Because the present Architecture Fireproofing Technique Criterion for Auto-Detection and Alarm Systems in Atria is one with faults, it can't satisfy the needs of practical use. According to the forms of atrium and the characters of gas flow, an Auto-Detection and Alarm System suitable for the atria is investigated. The aim of this paper is to discuss the perfect design method for the Auto-Detection and Alarm Systems in Atria.     

盐城市气象因子与水稻产量关系的研究

为了综合分析气象因子与盐城市水稻产量的关系及各个年份的丰歉指标,利用同异分析法对盐城市2001-2009年度水稻全生育期的主要气象因子进行了分析评价。结果显示：2001、2002和2004年为丰产年份,2005、2008和2009年为平产年份,2003、2006和2007年为歉产年份;并与对应年度的水稻平均产量表现对比,其结果非常接近。同时也验证了同异分析法在研究气象因子与水稻产量关系研究中的应用价值。     

大麻GRAS转录因子家族的全基因组鉴定及镉胁迫下表达分析

GRAS转录因子在植物生长发育及抗逆境胁迫中具有重要作用。本文对大麻GRAS转录因子家族进行了全基因组鉴定,对其理化性质、系统进化发育、基因结构、基因间的共线性关系进行了分析,并利用云麻1号及内蒙古小粒大麻的转录组数据分析其在镉胁迫下的表达量变化。结果表明,大麻基因组中鉴定出54个GRAS基因, 96.30%的基因编码酸性蛋白,长度为415～757aa,分子质量为46,405.05～85,748.52kD,等电点为4.77～8.54,划分为9个亚家族,其中PAT1、LS、SHR、HAM保守性较高, PAT1、LISCL、CsGRASA出现大量基因串联重复, CSGRAS12基因在5种植物的共线性分析中均存在。将2个大麻品种进行镉胁迫处理发现,云麻1号株高下降10.48%,鲜重下降6.33%;内蒙古小粒大麻株高下降66.07%,鲜重下降42.67%,表明云麻1号较内蒙古小粒大麻更耐镉胁迫。云麻1号的54个GRAS基因中, 42个(77.78%)基因表达上调1.05～18.10, 11个(20.37%)基因表达下调0.13～0.91;内蒙古小粒大麻的54个GRAS基因中, 27个(50.0...     

不同建筑热工分区办公建筑外围护结构负荷指标影响因素权重

为研究多因素对不同热工分区办公建筑总负荷指标的综合影响,在分析了单一因素对建筑总负荷指标影响规律的基础上,采用层次分析法对分别位于哈尔滨、兰州、重庆、广州的办公建筑负荷指标进行了评价。得到了窗户传热系数K_w、玻璃遮阳系数S_c、窗墙比R在不同热工分区办公建筑总负荷指标影响因素中的权重值,并对此进行了一致性检验。结果表明：对于严寒地区的哈尔滨和寒冷地区的兰州节能建筑,各因素重要程度为R > K_w > S_c;对于夏热冬冷地区的重庆和夏热冬暖地区的广州节能建筑,各因素重要程度为S_c > R > K_w。在建筑结构优化设计中应根据各热工分区负荷影响因素的比重不同进行优先控制相应因素。