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 125 毫秒
1.
This paper conducts the full size three-dimensional combustion numerical simulation study on the low-calorific value coal bed gas combustor. It explors the effects of different ratios of swirling wind and straight wind on flow field,temperature field and concentration field when this combustor combusts coal bed gas which methane volume concentration is 30 percent. The optimal ratio of swirling wind and straight wind is gained. Based on this,the number and obliquity of cyclone vane in gas pipeline are further optimized. The results show that when ratio of straight wind is 80 percent and ratio of swirling wind is 20 percent,the good jet flow rigidity is not only possessed,but also the strong spin momentum is brought. Reverse axial velocity grads and reverse velocity in central backflow region are also big,the burning temperature and combustion efficiency are high,and high-temperature region is diffusely distributed. When the number and obliquity of cyclone vane are respective 6 and 60,the mass fraction of methane descends quickly,the mass fraction of methane is low in outlet of combustion region,and the combustion efficiency is high.  相似文献   

2.
为了了解黑龙江省水稻产量与气候因子的关系,通过采用SPSS软件分别研究1980-2010年黑龙江省温度、降水量、相对湿度与水稻单产量,温度逐年差、降水量逐年差、相对湿度逐年差与水稻单产量逐年差的相关性。结果表明,水稻单产量与日平均气温、降水量和相对湿度的相关系数分别为0.399、-0.380和-0.422,都在0.05水平上显著相关,且日平均气温对水稻单产量影响最大,降水量次之,相对湿度影响最小;水稻单产量的逐年差与日平均气温的逐年差、降水量的逐年差和相对湿度的逐年差的相关系数分别为0.680、-0.650和0.600且均在0.001水平上显著,且日平均气温的逐年差与水稻单产量的逐年差的相关系数最大、其次是降水量的逐年差、最后是相对湿度的逐年差。  相似文献   

3.
We discuss the development of coal bed micro structure and the mechanism of enhancing the desorption/diffusion of coalbed methane by ultrasound. We present a mathematical model to describe the desorption/diffusion process of coalbed methane due to the ultrasound heating effect. Two cases of gas release with or without ultrasound fields in coal samples were simulated. We found that the temperature and the micropore diffusion coefficient of the system were improved by ultrasound transferred heat energy, while the dynamic fraction of free gas in pores was enhanced and the dynamic fraction of adsorbed gas was weakened.  相似文献   

4.
基于BP神经网络的冬季日光温室小气候模拟   总被引:6,自引:3,他引:3  
为了系统分析日光温室内外气候特征的关系,向日光温室作物环境调控及小气候预报提供支持,根据冬季日光温室内小气候观测试验资料和附近气象站观测资料,利用BP神经网络方法建立3个模型,分别对3种不同天气状况下石家庄地区日光温室冬季小气候特征进行模拟。结果表明,3个模型气温训练值与实测值的均方根误差(RMSE)都在2℃以内,决定系数都在0.95以上;相对湿度训练值的RMSE都在2个百分点以内,决定系数均高于0.95;接受到的太阳辐射的训练值与实测值的RMSE都在16 W/m2以内,决定系数也均超过0.95。利用此模型得到的气温预测值与实测值的RMSE都在2℃以内,决定系数都在0.9以上;相对湿度预测值与实测值的RMSE都在4个百分点以内,晴天和少云-多云状况下决定系数均高于0.9,寡照状况下的决定系数略低,约为0.8;接受到的太阳辐射的预测值与实测值的RMSE都在26 W/m2以内,决定系数均超过0.95。说明所建BP神经网络模型对于不同天气状况下石家庄地区日光温室冬季小气候特征模拟都有较高的精度,可以用于预测。  相似文献   

5.
为了揭示空气负氧离子浓度与林种及相关气象条件之间的关系,笔者于2013年夏、秋两季对北极村地区选取的具有代表性的样地进行负氧离子浓度的观测及研究,通过时间尺度平均值及相关性分析的方法,对采集数据进行统计分析,并得出北极村地区负氧离子浓度的总体水平以及其与林种和气象因子之间的变化关系。结果表明:漠河北极村空气负离子浓度的总体水平处于548~1203个/cm~3,平均值为892个/cm~3,负氧离子浓度大体上与空气温度呈正相关、与空气湿度呈负相关。落叶松样地整体负氧离子水平高于樟子松样地,不同季节对负氧离子浓度也有较大影响。揭示出北极村地区负氧离子浓度与林种、季节以及气象因子之间的变化关系。  相似文献   

6.
接种量对醋渣干发酵的影响   总被引:3,自引:0,他引:3  
以醋渣为原料,在严格控制厌氧发酵温度的条件下(38±1℃),采用批量进料发酵工艺,研究不同接种量对其厌氧干发酵性能的影响。结果表明:醋渣与污泥质量比为2:1(干物质量比3.05)、质量比为1:1(干物质量比1.52)、质量比为1:2(干物质量比0.76)厌氧发酵TS产气潜力分别为270.35、314.67、408.22ml/g, VS产气潜力分别为295.56、344.02、446.95ml/g;加大接种量能够避免酸化、快速启动厌氧发酵、加快产气高峰的出现、减短发酵周期、提高原料产气率等。  相似文献   

7.
江西脐橙高温低湿灾害气候特征及原因分析   总被引:2,自引:1,他引:1  
为研究脐橙生理落果期的高温低湿气象灾害,利用1961—2013年江西省87个气象台站脐橙生理落果期逐日平均气温、最高气温、相对湿度等资料,分析高温低湿灾害的气候特征;对1981—2013年高温低湿日数与西太平洋副热带高压环流指数进行统计相关分析。结果表明:近53年江西省高温低湿日数呈明显增加趋势,21世纪前高温低湿日数总体变化不大,但21世纪后显著增多。江西高温低湿灾害易发区主要在赣南和赣东北。高温低湿灾害日数在20世纪末出现了由少变多的显著突变,突变后高温低湿灾害日数比突变前增多2.4天。近53年脐橙生理落果期气温明显升高,空气湿度显著减小,气温升高、空气湿度减小是导致脐橙高温低湿灾害增多的主要原因。高温低湿日数与西太平洋副高指数密切相关,3月脊线位置北抬,5月西伸脊点偏东,高温低湿日数都将明显增多。  相似文献   

8.
Night chilling (5 °C) subsequently lowered photosynthetic intensity in the leaves of maize seedlings at 20 °C through an increase in leaf diffusive resistance brought on by lower tissue water content in morning hours. A more significant increase in leaf diffusion resistance was observed when soil temperature was lowered than in the case of lower air temperature.
The unfavorable effect of soil and air cooling temperature on photosynthesis was limited by air saturated with water vapour. However, as a result of lowering the night temperature from 5 °C to 1 °C, the efficiency of the protective influence of higher atmospheric humidity was decreased. This demonstrates that the participation of factors unrelated to plant water status in inhibiting photosynthesis increases with lower night temperatures.
An additional reason for inhibited photosynthesis following cool nights was a decrease in chlorophyll accumulation, below 50 μg per 1 cm2 of leaf area.  相似文献   

9.
葡萄霜霉病田间初始发生相关因素分析   总被引:1,自引:1,他引:0  
【目的】为明确葡萄霜霉病田间初始发生与孢子囊、气象因素及葡萄品种的关系。【方法】连续6年定点调查了无核红宝石、玫瑰香、蛇龙珠上的葡萄霜霉病初始发生时期,同时利用孢子囊捕捉器捕捉葡萄霜霉病菌孢子囊,并通过农田小型气候站监测田间气象数据,分析温度、湿度、降雨等气象因素与霜霉病初始发生的关系。【结果】结果表明在葡萄霜霉孢子囊发现后10 d左右,田间始见病斑;不同品种葡萄上霜霉病的初始发生时期有所不同:红宝石发病最早,其次为玫瑰香,蛇龙珠发病最晚;葡萄霜霉病的发生与气温、相对湿度、降雨量等气候条件密切相关,其中降雨量是影响葡萄霜霉病初始发生的主导气象因子。【结论】通过对以上数据分析,本研究提出多种直接又简便的预测方法,用于葡萄霜霉病的预防防治。  相似文献   

10.
为探讨雪茄烟支含水率与不同环境温湿度之间的关系,分别选取叶束式雪茄和叶片式雪茄两款雪茄产品,在保证烟支初始水分等其他因素一致的条件下,改变环境温湿度,测量烟支水分达到平衡时的水分值。通过烟支含水率与环境温湿度之间的相关性分析,建立不同规格雪茄烟支含水率与环境温湿度之间的线性回归方程。结果表明,在一定范围内,雪茄烟支含水率与环境温度呈负相关、与环境温度呈正相关关系。通过方差分析和残差分析对线性回归方程进行检验,并结合生产实际对回归方程进行验证。  相似文献   

11.
日光温室小气候要素预报模型研究   总被引:1,自引:0,他引:1  
了解日光温室小气候要素变化规律,建立小气候要素预报模型,可以对日光温室资源合理开发,为日光温室小气候调控提供依据。应用辽宁省沈阳市东陵区日光温室暖棚内农田小气候观测仪采集的逐小时气温、相对湿度数据,将冬季、春季、秋季和晴天、多云、阴天几种情况进行组合,计算棚内日最高气温、日最低气温、日平均相对湿度,分析其变化规律,并利用自动气象观测站数据,建立基于逐步回归方法的预报模型。分析结果表明,日光温室内日最高气温和日最低气温呈现春季、秋季温度值接近,冬季明显低于春秋两季的特征;而冬季日平均相对湿度高于春秋两季。日最高气温具有显著的从晴天至多云至阴天减少的变化特征,日最低气温特征不如日最高气温明显;日平均相对湿度为从晴天至多云至阴天增加的变化特征。所建立的日光温室小气候要素逐步回归预报模型,均通过了显著性检验,相关系数为0.608~0.933,相对误差范围为0.1%~19.0%,相对误差平均值为2.7%~9.9%。  相似文献   

12.
In this study, the concentrations of PM10, PM2.5 and PM1 in a residential building in Shanghai were measured under minimum ventilation rate (external doors and windows closed), and the relationship between the indoor and outdoor PM concentrations (I/O ratio) and the influence of temperature and relative humidity were analyzed as well. Results showed that, the percentages of the concentrations of fine particles (PM2.5) of the indoor and outdoor air were 65% and 87% of the inhalable particulate(PM10)concentration during the test respectively. The I/O ratio was less than 1 without significant indoor sources. Meanwhile, the figure decreased as the size of particles decreased. Results also indicated that, the correlation between indoor and outdoor PM concentrations, PM1 and PM2.5 were more obvious than PM10, and the correlations showed obvious differences according to the weather conditions.The PM concentration was influenced by temperature and relative humidity, which was presented to be complex when affected by weather conditions.  相似文献   

13.
In this study, phenological and meteorological data have been used to interpret variations in a time series of regional average yields and quality parameters of malting barley (Hordeum vulgare L). The analyses were focused mainly on the grain filling period. Duration and occurrence of this development stage showed remarkable differences from year to year, as heading varied over more than four weeks and yellow ripeness over two weeks in the investigation period from 1974 to 1996. Yields above average were achieved only in years when grain filling duration exceeded 42 d. Protein concentrations below 10.5 % and grading percentages over 90 % required at least 44 d of grain filling. Temperature had the strongest influence on the length of grain filling, even though the calculated Growing Degree Days (base temperature 3 °C) were not absolutely constant. Mean daily temperature and relative air humidity were the best estimators with respect to grain yield. An optimum temperature range was found between 14 and 18 °C. Assuming a linear relationship, yield reductions between 4.1 and 5.7 % have been calculated for every 1 °C increase of the mean daily temperature. Relative air humidity was the best single estimator for grain protein concentration. The results of this study suggest that relative humidity during grain filling can be a more suitable parameter to describe drought stress effects than precipitation amounts from heading to yellow ripeness or from January 1 to yellow ripeness.  相似文献   

14.
为改进白肋烟晾制技术,利用温湿度自动记录仪定时测量白肋烟晾制期间晾房内的温度和相对湿度,在晾房内加装循环通风风机调控温湿度,分析了白肋烟晾制期间晾房内外的温湿度差异,比较了加装风机循环通风对晾房温湿度的影响。结果表明,晾房内温湿度主要受外界天气的影响,但晾房可缓解外界天气的影响;晾房内温度变化与相对湿度变化呈相反趋势,温度高时相对湿度低,温度低时相对湿度高;晾房内上层温度较下层高,上层湿度较下层低。在晾房内加装风机能够调控晾房内的温湿度状况,可适度减少晾房上层与下层的温湿度差异,但是由于晾房内温湿度主要受外界气象条件影响,仅安装循环风机对降低晾房内相对湿度的效果有限。  相似文献   

15.
为比较新疆南北疆集约化养殖场冬季肉牛舍环境指标,本研究选择新疆阿克苏地区拜城县(南疆)和伊犁地区昭苏县(北疆)2 个集约化养殖场为对象,对其冬季肉牛舍光照强度、温度、湿度、噪音、CO2、NH3、CH4、PM10和TSP 等环境指标进行连续5 天08:00、12:00、18:00 和21:00 及3 天连续24 h 的测定,然后将2 个集约化养殖场数据进行比较。结果表明:拜城牛场光照强度、温度平均值及昭苏牛场温度、湿度平均值超出国家牲畜和家禽养殖场的环境质量标准(NY/T 388—1999)。此外,拜城牛场温度、湿度平均值极显著低于昭苏牛场(P<0.01)。昭苏牛场CO2浓度超出NY/T 388—1999,CO2、NH3浓度平均极显著高于拜城牛场(P<0.01)。上述环境指标连续24 h 变化表明,2 个集约化养殖场的温度都低于NY/T 388—1999;拜城牛场湿度52.7%~86.4%,全天有12 h 超出NY/T 388—1999,昭苏牛场湿度69.4%~97.4%,全天有18 h 超出NY/T 388—1999。拜城牛场CO2浓度为687.6~1799 mg/m3,在18:00 和19:00 超出NY/T 388—1999,昭苏牛场CO2浓度1459.6~3392.0 mg/m3,除05:00 时,其他时间都超出NY/T 388—1999。以上结果表明,南北疆冬季牛场环境指标存在较大差异,南疆拜城县牛场主要在于增加光照与保温,而北疆昭苏县牛场主要应该解决保温与改善圈舍空气环境的矛盾。  相似文献   

16.
烘烤工艺对‘KRK26’烟叶细胞超微结构变化的影响   总被引:1,自引:1,他引:0  
为了研究不同烘烤工艺对烟叶细胞超微结构的影响,以烤烟KRK26中部叶为材料,对低温低湿条件、中温中湿条件、中温高湿条件3种烘烤过程中烟叶细胞超微结构的变化进行观察。结果发现:(1)在3种烘烤工艺下,叶绿体形态变化、结构解体的速度是不同的。低温低湿条件下出现时间晚,但速度快;中温中湿条件下,出现时间早,速度慢;中温高湿条件下,出现时间早,但速度慢。(2)在3种烘烤工艺下,线粒体的形态、嵴数量和膜结构的变化解体速度都表现为低温低湿条件下〈中温高湿条件下〈中温中湿条件下的现象。  相似文献   

17.
为探明大兴安岭针叶林空气负离子浓度日变化特征,选择2012年、2013年的夏、秋2季,于漠河北极村附近分别选取100m2的樟子松、落叶松林地,测量并分析2处样地的空气负离子浓度与季节、测量点位置和温湿度等环境因子在日变化上的相互关系。研究表明,针叶林空气负离子日平均浓度在中午12时达到峰值,为1155个/cm3,在凌晨2时达到谷值,为254个/cm3,夏季针叶林空气负离子平均浓度高于秋季。落叶松林地空气负离子浓度平均水平高于樟子松林地。空气负离子浓度在林地边缘密度略大于林地中心。通过相关分析,针叶林地空气负离子浓度与空气温度呈极显著正相关,与空气湿度呈显著负相关。空气负离子浓度不仅可以评价空气清洁水平,也是衡量环境质量的重要参数。  相似文献   

18.
基于2011—2018年油菜开花日挂牌标记试验,考种不同开花时段油菜结荚率、单荚子粒数,分析不同时期低温对油菜结实的影响,建立气象因子与油菜子粒损失率的影响定量关系。结果表明,2月25日前的低温对油菜结实的影响以中度和重度为主,3月中下旬的低温对油菜结实的影响以轻度为主,2月26日—3月10日的低温对油菜结实的影响以轻度和中度为主。油菜子粒损失率与开花时日最低气温平均值、日平均降雨量相关不显著,与开花时平均气温、日最高气温平均值、日照时数平均值、日平均相对湿度相关显著。随开花平均气温下降,日最高气温平均值下降,空气相对湿度升高。开花时空气相对湿度为70%,且日平均气温≤6.9℃,或空气相对湿度为80%,日平均气温≤8.0℃,油菜中度受害;开花时空气相对湿度为80%,且日平均气温≤4.3℃,或空气相对湿度为85%,日平均气温≤4.8℃,油菜重度受害。其次分析确定了不同天气类型下油菜开花结实的冷积温指标,当日照低温天气的冷积温指标为≥16.5℃,或无日照低温阴雨天气的冷积温指标为≥5.0℃,为中度受害。当日照低温天气的冷积温指标为≥37.5℃,或无日照低温阴雨天气的冷积温指标为≥26.0℃,为重度受害。试验结果可为油菜灾害预警评估和减灾防灾农业气象服务提供技术支撑。  相似文献   

19.
Based on Fourier and Fick law, a modified Budaiwi model considering phase change within wall and the effect of solar radiation was established by using air humidity ratio in wall and temperature as the driving potentials.The term omitted in the mass transfer equation of the original model was added in the modified model.To evaluate the accuracy of the model, a test system was set up to measure relative humidity and temperature within a porous wall under actual weather conditions and compared with the prediction of the model.It was found that the predictions were in good agreement with the experimental results.At the interface close to outdoor, the average deviation of the relative humidity was 4.44% and average temperature deviation was 1.31K.At the interface close to indoor, the average deviation of the relative humidity was 6.3% and average temperature deviation was 1.26K.  相似文献   

20.
本研究以不同穗型的3个品种沈稻11、辽粳294和沈农9816为试材,研究了水稻群体间的温湿度特征。结果表明,白天不同品种水稻群体中温度和相对湿度的变化趋势与大气一致。水稻群体中露点温度的脉动远大于温度和相对湿度,总的趋势是中午露点温度较高。不同水稻群体中温度的差异小于湿度。从8月上旬至9月中旬,不同品种群体中的温、湿度差异逐渐增大,弯穗品种群体中的温度低于直立、半直立穗品种,湿度大于直立、半直立穗品种,直立和半直立穗品种之间的差别不太大。  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