首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
为了揭示冻结气温降幅对潜水入流量的影响,通过室内冻结试验装置设定地下水位埋深为87.5 cm,进行了3种冻结气温降幅,2种土壤质地的单向土壤冻结试验,监测潜水入流量的变化。结果表明:大幅降温冻结下,潜水入流速率较大,冻结第41天砂壤土和粉质粘壤土潜水入流量分别较小幅降温冻结下的潜水入流量高51.8 mm和50.7 mm;冻结气温降幅越大,潜水入流量受土壤质地的影响越明显,小幅降温、中幅降温和大幅降温冻结下,第41天砂壤土潜水入流量较粉质粘壤土潜水入流量分别高8.6 mm、11.5 mm和14.2 mm;土壤颗粒直径越小,潜水入流量对冻结气温降幅的响应越早。研究成果对于地下水浅埋区地下水资源量的科学评价和土壤盐碱化防治等具有重要的指导意义。  相似文献   

2.
Alumina content in Nanjing Steel blast furnace slag is up to 19%, which results in worse slag fluidity, higher furnace operating temperature and higher silicon content of hot metal. Therefore blast furnace strengthening is reduced. Aiming at this problem, an by laboratory experiments the viscosity of simulating Nanjing Steel BF slag samples are measured after adding MnO, which are made up of analytically pure chemical reagents. And according to the experimental results, the influence of MnO on the properties of high alumina content BF slag is analyzed and the methods of reducing silicon content of hot metal in Nanjing Steel is educed. The results showed that the addition of MnO in high Al2O3 content slag has stronger effects on viscosity decreasing, and the decreasing of slag viscosity would make it possible to reduce the operating temperature of the blast furnace, which would result in decreasing of silicon content of hot metal.  相似文献   

3.
The influence of the explosive blast with different pressure on the permeability of the pulmonary microvascular endothelial cells monolayer (PMECM) has been observed by using the model of the explosive blast wounded the endothelial cells monolayer in vitro The mechanism of the effect of the blast on PMECM permeability has also been explored in pathology and cytoskeleton. The results show that the explosive blast with about 100 kPa pressure can increase the permeability of PMECM in conductance detection, and the explosive blast with lower than 350 kPa pressure can mainly cause the increasing of the gap between endothelial cells, and explosive blast with higher than 600 kPa pressure can exfoliate the endothelial cells monolayer. The occurrence mechanism of PMECM permeability changes caused by explosive blast is related to the change of the cytoskeleton myosin.  相似文献   

4.
热风与微波干燥胡萝卜的工艺研究   总被引:4,自引:0,他引:4  
用热风干燥、热风和微波组合干燥对胡萝卜进行干制,检测不同干燥方法对胡萝卜干制品感观品质、复水比、VC含量的影响。结果表明,利用不同的干燥方法所获得的胡萝卜干制品的复水性能和感官品质有明显差异,热风与微波联合干燥胡萝卜制品的品质最优。降低热风温度,缩短热风干燥时间,减小热风速率和微波加热功率,均可提高干制品的复水性、VC含量及其品质。  相似文献   

5.
为研究灰黄霉素对水稻稻瘟病菌的抑制作用及其对稻瘟病的防治效果。采用对峙法测定产灰黄霉素的展青霉GM120-43对稻瘟病菌抑制作用、菌丝生长速率法测定灰黄霉素对稻瘟病菌的毒力试验以及盆栽防治稻瘟病试验。结果表明:展青霉GM120-43对稻瘟病菌具良好的抑制作用;在稻瘟病的防治中,灰黄霉素稀释300倍时,预防叶瘟病与穗瘟病的效果分别为93.76%和53.79%,治疗效果分别为89.2%和49.21%。在所试验的浓度范围内,灰黄霉素防治效果与其浓度成正比,是一种具有前景的生物农药。  相似文献   

6.
连续阴雨天气对水稻灌浆中后期稻瘟病发生的影响   总被引:1,自引:1,他引:0  
为明确水稻灌浆中后期的连续阴雨天气对稻瘟病发生的影响,本研究对镇江市2011—2016年10月份气象条件和稻瘟病发生情况进行相关性分析。结果发现:水稻灌浆中后期稻瘟病病情指数与10月份的平均低温呈正相关、相关系数0.929、关系极显著,与相对湿度≥90%的天数呈正相关、相关系数0.883、关系显著,与月降雨量呈正相关、相关系数0.761,与雨日呈正相关、相关系数0.671,与日照时数呈负相关、相关系数-0.775。10月份的连续阴雨天气和较高的平均低温对未防治区稻瘟病的影响程度重于对2次药剂防治区的影响;对防治区水稻稻瘟病的影响为枝梗瘟、谷粒瘟发生加重,对未用药区稻瘟病的影响为穗颈瘟发生加重;对感病品种稻瘟病发生影响较大,对中抗品种影响较小。因此,在连续阴雨天气到来前,建议使用不同作用机理的药剂再防治1次,对稻瘟病的后期扩展具有一定抑制作用,可有效减少褐斑谷粒比例,提高稻谷卖相、销售价格和农民收入。  相似文献   

7.
The multi-branch tunnel has multiple routes for smoke extraction and air supply, consequently its ventilation and smoke control modes could have multiple solutions owing to the competitive effects of buoyancy and fan power. For the smoke control of a multi-branch tunnel, the mass and energy balance equations for every possible flow pattern were established, and the corresponding multiple solutions were obtained using mathematical methods. The results demonstrate that, even though the exhaust ventilation mode and fan type have been determined in accordance with the anticipation, multiple states of exhausted flow remain and the operation point of the fans will drift away from the design accordingly. This could cause a totally different direction of smoke route from the anticipated one. It is also shown that the type of fan has significant effects on the existence of multiple solutions.  相似文献   

8.
顾鑫 《中国农学通报》2017,33(18):133-136
针对稻瘟病严重影响黑龙江省东部地区水稻生产这一情况。试验于2006-2015年在黑龙江省东部地区9个地点进行定点、定期调查水稻稻瘟病的发生情况,并收集稻瘟病侵染期的气象因子,采用通径分析及逐步回归的方法对水稻稻瘟病的病情指数与气象因子之间的关系的进行了研究,明确了7月份、8月份的平均气温为影响稻瘟病发生流行的主要气象因子,并建立短期预测模型:Y=-85.171163 0.41315X1 1.23231X2-0.1817X4-0.09418X5 0.167333  相似文献   

9.
以鲤鱼为原料,探讨了NaCl及其复合溶液浸泡脱腥对鱼腥味的影响,调味配方及干燥方法对产品的影响。结果表明,采用质量分数1%的NaHCO3+6%NaCl+10%C2H5OH溶液浸泡30 min,选择质量分数65%五香料+22%白砂糖+1%味精+7%料酒+3%辣椒粉+2%精盐和以6%白砂糖+2%味精+7%料酒+3%辣椒粉+2%精盐+80%水分别作为五香味、鲜辣味鲤鱼干的调味配方,微波低火处理19 min后,在100℃的鼓风干燥箱中干燥30 min,为较佳的工艺组合。  相似文献   

10.
Durable resistance to rice blast disease-environmental influences   总被引:5,自引:0,他引:5  
J. M. Bonman 《Euphytica》1992,63(1-2):115-123
Summary Blast is one of the most serious diseases of rice worldwide. The pathogen,Pyricularia grisea, can infect nearly all parts of the shoot and is commonly found on the leaf blade and the panicle neck node. Host resistance is the most desirable means of managing blast, especially in developing countries. Rice cultivars with durable blast resistance have been recognized in several production systems. The durable resistance of these cultivars is associated with polygenic partial resistance that shows no evidence of race specificity. This partial resistance is expressed as fewer and smaller lesions on the leaf blade but latent period does not appear to be an important component. Partial resistance to leaf blast is positively correlated with partial resistance to panicle blast, although some cultivars have been found showing leaf-blast susceptibility and panicle-blast resistance. A diverse set of environmental factors can influence the expression of partial resistance, including temperature, duration of leaf-wetness, nitrogen fertilization, soil type, and water deficit. Because of the great diversity of rice-growing environments, resistance that proves durable in one system may or may not prove useful in another. In highly blast-conducive environments, other means of disease management must be applied to assist host-plant resistance.  相似文献   

11.
梨树大棚栽培棚内外温湿度环境变化规律和物候期研究   总被引:2,自引:0,他引:2  
为梨大棚栽培技术的制定提供参考依据,对梨树大棚栽培棚内外空气温度、空气相对湿度、土壤温度以及梨树物候期的变化特点进行比较。结果显示:(1)随季节的变化,气温和地温均呈逐渐上升趋势, 6月之前棚内气温、相对湿度和地温均高于露地,且昼夜温差大于露地,6月起棚内外温度差异不显著。(2)棚内栽培‘翠冠’和‘黄冠’梨萌芽早,但落叶晚,整个营养生长期分别为242天和231天,分别比露地长27天和37天。(3)大棚栽培的‘翠冠’和‘黄冠’梨开花期比露地皆提早18天,且花期比露地长2天。(4)棚内栽培条件下,‘翠冠’和‘黄冠’梨采收期分别提早13天和14天,而果实发育期比露地分别长5天和4天。研究结果表明,大棚条件下温湿度高,开花期提早,果实成熟期提前,南京地区可进行梨保护地栽培。  相似文献   

12.
辽宁省春季表层地温变化特征及其与气温的关系   总被引:5,自引:2,他引:3  
为揭示春季地温对各气象因子的关系与响应程度,总结地温变化规律,以辽宁地区为研究区域,通过利用1981—2010年3—5月辽宁省49个气象站的地温、气温、日照时数、太阳辐射、平均风速、水汽压、相对湿度、降水逐日资料,采用气候倾向率、相关分析、回归分析、因子分析等统计方法研究了近30年辽宁地区地温变化趋势及其气象影响因素。结果表明:随土壤深度的增加,地温与气温的差值逐渐降低,辽宁中部地温与气温差值相对较小;辽宁西部地温>辽宁东部地温>辽宁地区气温;地温与8种气象因素特别是气温的关系更为紧密且有显著的正相关性。在春播期地温预报中,应结合地形地貌特点充分考虑这些气象要素带来的影响。  相似文献   

13.
The gas-solid two-phase flow characteristics of fine particles in the filter media were simulated based on CFD-DEM (Discrete Element Method) in this study, and the particle group, particle size distribution, and the rebound effect between particles, particle and fiber were taken into account the calculations. Additionally, the movement characteristics of the particle group and the deposition form of the fine particles in the fibrous filtration were analyzed. The results indicate that it is convenient and feasible to simulate the filtration process of the filter media as well as the deposition process and form of the fine particle on the media surface using CFD-DEM, and the simulation results are consistent with the experimental observations in the literature. The surface filtration has larger contribution to the filtration process, and most of the particles are captured by the media surface. Meanwhile, parts of smaller particles that enter into the media are captured by the depth filtration. A larger number of particles are collected by the particle-particle capture mechanism. The filtration efficiencies of the filter media are varied with the particle systems, and for the model of the filter media in this study, the filtration efficiency of the multi-particle system is about 20% higher than that of the single-particle one.  相似文献   

14.
南充市水稻稻瘟病区划和发生流行规律研究   总被引:4,自引:3,他引:1  
为提高南充市水稻稻瘟病监测预警和综合防控水平,切实减轻稻瘟病危害,采用GPS和GIS定位、系统监测和普查、品种抗稻瘟性鉴定、稻瘟病菌生理小种监测和气象资料分析等方法,开展了南充市水稻稻瘟病发生流行区划、精准勘界和发生流行规律研究。首次明确了南充市稻瘟病的流行区划和精准勘界,探明了水稻稻瘟病菌越冬后的初始侵染源(即始见期)地点、发生特点、流行趋势和特点,明确了南充市水稻稻瘟病在田间存在4个流行高峰期,其中第1个流行高峰期发生面积对当年病害流行起着决定作用,5月底的累计发生面积与年发生面积成正相关,相关系数为0.8172;建立了孕穗末期病田率和蜡熟期病株率同年发生面积预测数学模型。对其成因探讨发现,导致南充市近年水稻稻瘟病重发及流行的内因是水稻品种抗稻瘟能力的降低或丧失、稻瘟病菌致病力强的生理小种增加与更强致病力的小种出现;温度适宜和阴雨寡照偏多是造成稻瘟病在南充市流行的外因。2001—2015年,全市水稻稻瘟病短期预报准确率达100%,中、长期预报准确率分别达到98%和95%以上,比1997年以前提高5~15个百分点,促进稻瘟病防效提高15%~30%。  相似文献   

15.
Through the statistical analysis of analyzed the particularity of karst surrounding rock classification, finally obtained the rock classification index system of south karst highway tunnel construction based on rock strength, rock complete coefficient ,groundwater state, structural plane state the structural plane strike to tunnel influence, karst development to tunnel influence. And the model is applied to tianshengqiao tunnel and guanshang 2 tunnel with the example verification, and compared with the classification results and experts judgment to get the accuracy is 93.3%.  相似文献   

16.
Through study of the rule of the air current between the metro stations which had installed the safety door system and the tunnel, this text established a physics model and a mathematics model, gained the mix coefficient which can marks the degree of the influence stopcock wind in metro inflict to the heat environment, exerting reasonable assumption and simplification, making use of the CFD imitation, adopting tracer air. The text elected three kinds of safety door system with different height to simulate and compare, gained the exact value of the mix coefficient, and simulated the energy consumption of subway air conditioning in different height of safety door by the mix coefficient.  相似文献   

17.
为更好地开展浙江沿海海上大风的预报服务,本研究对2012年1月1日—2014年12月31日的ECMWF细网格10 m风场产品在浙江沿海的预报性能进行评估,并将其插值到沿海站点和观测数据进行对比分析。结果表明:冷空气影响下,浙江沿海的平均误差为负值,绝对误差分布和变化趋势与平均误差基本一致;台风影响下,24 h预报时效的平均误差为正值,随着预报时效的增加,平均误差逐渐转为负值,鱼山渔场、温台渔场及舟外渔场的绝对误差较其他区域大。另外,预报值和观测数据间的相关系数随预报时效的增加而减小,两者之间的相关系数平均值随海拔高度的增加而减小;ECMWF细网格对岱山和龙山村的预报偏大,对浪岗的预报偏小,预报偏差的离散度随预报时效增加而增大。  相似文献   

18.
试验以露地移栽为对照,研究了地膜覆盖和地膜覆盖加拱棚2种增温处理对基质育苗移栽棉花缓苗期的影响,结果表明,在缓苗期内,不同的增温处理对叶绿素影响不大,丙二醛MDA和脯氨酸含量均随生育进程呈现先增加后下降趋于稳定的趋势,覆膜和覆膜加拱棚较露地移栽含量低,温度高有利于缓解棉苗的受胁迫程度;3种不同处理条件下,超氧化物歧化酶...  相似文献   

19.
The flame ceiling jet is easily formed while the on fire train stops in the tunnel. The iterative formula is derived to calculate the average temperature of the flame ceiling jet when the fire source is set on the center of the train by establishing a one dimensional model of the unit control volume, and the heat exchange is considered among the flame smoke and the wall of the tunnel and the train. Undetermined coefficients in the iterative formula are determined by small scale model experiments with the scale factor of 1:8 and numerical simulation. The calculated values of temperature by the iterative formula are consistent well with the measured values, and the maximum error of calculation is no more than 7%, which indicates that the iterative formula is reliable. The results show that the distributions of the average temperature of flame ceiling jet are in the exponential form, but there are some differences between that above the train and that in the tunnel. Two prediction formulas for the flame ceiling jet average temperature changing along the longitudinal tunnel are obtained by the sub fitting method. The results can provide reference for the alarm parameter selection, device settings in tunnel, safety evacuation of the passenger, as well as the analysis of the destructive effects on the tunnel lining structure caused by tunnel fire.  相似文献   

20.
The acoustic environment of highway tunnel is complex and has influences on the driving safety and comfort. In case of emergency, evacuation information is difficult to transfer. Finite element method is used for calculating highway tunnel acoustic modal and attenuation characteristics. The results show that acoustic mode of highway tunnel has symmetry in the horizontal pressure amplitude of symmetry regional is equal and phase is the same or opposite. The higher modal frequency, the greater sound pressure amplitude is, and the effect of tunnel length on modal frequency is smaller. Decay curves of pressure level at each point in the highway tunnel over time are nonlinear. After the source excitation, in 1.5 s, attenuation rate is faster than that of few seconds later and the attenuation time of sound pressure level 30 dB is 5.5 to 7 s.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号