高压脉冲电场与温和热对液态蛋协同杀菌动力学和工艺研究

本文研究了高压脉冲电场（PEF）与温和热（15、30和55℃）对蛋清的协同杀菌效果,建立了动力学模型。结果表明：PEF在15、30和55℃下对大肠杆菌的致死作用都较好地符合一级动力学模型（R2>0.97）,杀菌动力学常数K值在4.5-13.2×10-3 (1/μs)之间。杀菌动力学常数K是电场强度和温度的函数,温度越高,电场强度越大,其杀菌一级动力学常数越大,表明PEF与温和热的协同效应越强。本文还确定了PEF与温和热对蛋清液杀菌的工艺, PEF（35kV/cm,400μs）在55℃下能够显著增强对蛋清液中四种指示菌的杀菌效果。PEF（35kV/cm,400μs）在15℃下可使蛋清中大肠杆菌、沙门氏菌、李斯特菌和金黄色葡萄球菌分别下降3.2、3.6、3.4和2.8个对数值;当温度升至55℃,四种指示菌的致死率分别提高到5.4、5.8、6.5和4.3个对数值。     

分阶段储粮降温通风的比较研究

采用试验观测的方法,对钢板仓仓储小麦分别进行不通风、两阶段和三阶段降温通风研究和分析。研究发现,相对于秋季两阶段通风而言,夏季增加一个通风阶段更有利于提高降温效果。在为期两年的试验中,在夏季合适的气温条件下,用较小的通风量进行降温通风,小麦有足够的时间与温度低于24℃的空气接触达到冷却的目的。然而,由于夜间空气温度低、湿度大的特点导致粮食最终温度高于24℃,同时由于送风湿度大的原因,粮食的水分也会相应增大。     

Climatic determinants of lowland rice development

Accurate modelling of plant development is the basis for any assessment of climate change impact on crop yields. Most rice models simulate development (phenology) based on temperature and photoperiod, but often the reliability of these models is reduced beyond the environment they were calibrated for. In our study, we tested the effects of relative air humidity and solar radiation on leaf appearance rate in greenhouse experiments and analysed data sets from field studies conducted in two extremely different rice-growing environments in Nepal and Senegal. We also analysed environmental effects on duration to flowering of one popular IRRI material (IR64) for eight different sites covering the entire temperature range where rice is widely cultivated. Both low relative air humidity and low solar radiation significantly decreased leaf appearance rate. Mean air temperature explained 81% of the variation in duration to flowering across sites, which was furthermore significantly influenced by relative air humidity. Across all sites, a simple linear regression approach including mean air temperature and mean relative humidity in the calculation of duration to flowering led to a root mean square error (RMSE) of 10 days, which was slightly lower than the RMSE of 11 days achieved with an automated calibration tool for parameter optimization of cardinal temperatures and photoperiod sensitivity. Parameter optimization for individual sites led to a much smaller prediction error, but also to large differences in cardinal temperatures between sites, mainly lower optimum temperatures for the cooler sites. To increase the predictive power of phenological models outside their calibration range and especially in climate change scenarios, a more mechanistic modelling approach is needed. A starting point could be including relative air humidity and radiation in the simulation procedure of crop development, and presumably, a closer link between growth and development procedures could help to increase the robustness of phenological models.     

Analysis of spatial electric field with point-plateelectrodes configuration using finite element method

To investigate the spatial electric field with the point-plate electrodes configuration, variations of the electric field intensity are analyzed for absolute air dielectric and liquid dielectrics contained in air dielectric based on the finite element method of numeric computation. The results show that the electric field intensity of the spatial electric field is great non-uniform with the point-plate electrodes configuration for absolute air dielectric, and it can be increased rapidly at the nozzle point to achieve a maximum value. Single oil drop existed in air dielectric induces a biggish deformation of the gradient of the electric field intensity in its neighbor field. Many oil drops along with horizontal distribution have an obvious tensioning operation on the electric field, so the electric field intensity on the normal at the nozzle point has an evident augment for overlapping effects among the oil drops, and it can spread electric corona area of the total spatial electric field.     

河北省中南部棉纤维品质与气象因子相关性研究

为明确气象因子对河北省中南部棉纤维品质影响,2007-2008年在南宫、辛集、保定三个生态点设置田间实验,供试品种为鲁棉研27号,研究表明：不同生态点、开花期间棉纤维比强度、2.5%跨长、马克隆值差异呈显著水平(p<0.05);不同开花期棉铃纤维伸长率差异呈显著水平;同比强度相关性呈显著水平的气象因子共5项,分别为日均温、日温差、日最低气温、日最高气温和平均相对湿度;2.5%跨长同日照时数呈显著正相关;同伸长率相关性呈显著水平的气象因子为日照时数和平均相对湿度;马克隆值同平均相对湿度和日温差呈显著负相关,与日最高气温呈正相关。棉纤维各项指标与影响其最大气象因子多项式拟合表明,当棉铃发育期日均温为25-26℃纤维比强度较好,日照时数为6.5-7.0小时,棉纤维伸长率最大,马克隆值适宜的日最高气温27-28℃或30-31℃。同时,建立了气象因子与纤维品质动态回归模型。研究结果将为棉纤维品质生态区划和品质生态模型定量化提供依据     

黑蒜的加工、组分及生理功能研究进展

黑蒜是一种新型大蒜制品,是以带皮蒜头为原料,在高温高湿环境下经酶解和美拉德反应加工而成的保健食品。文章归纳了黑蒜的恒温保湿和变温保湿加工特点,分析了黑蒜与普通大蒜相比发生的组分变化,综述了黑蒜具有抗氧化、抗癌、调节免疫、调节血脂、减缓宿醉症状等多种生物活性,指出黑蒜具有较强的生物活性是其在加工过程中多种活性成分增加和生成的结果,并对黑蒜的研究方向进行了展望。     

Effect of Low Night Temperatures on Photosynthetic Activity of the Maize Seedlings (Zea mays L.)

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.     

屋顶花园对建筑微气候的影响

通过对屋顶绿化和对照屋顶主要气候要素的观测,对各时段屋顶内外表面的温度、空气温度、空气湿度的变化进行了研究和相关分析。研究表明应用屋顶绿化形式可以部分改变温湿度,可以降低室内气温约1℃,降低室外气温约1.7℃,增加室内湿度2%~4%。     

日光温室不同种植位置温光变化及对结球生菜产量的影响

研究旨在探索基于日光温室条件下科学高效的种植模式,为实现日光温室蔬菜科学化种植、统一化管理、标准化生产奠定理论基础。通过监测分析温室不同种植位置的气温、地温、湿度以及光照强度,研究不同种植位置的温湿度及光照变化规律。同时,选取8个结球生菜品种,分畦测定不同品种生菜的产量,研究日光温室不同种植位置对结球生菜产量的影响。结果表明,温室不同种植位置的温度、湿度、光照强度均存在较大差异,气温、地温由南向北逐渐升高,光照强度先升高后降低。由于温光条件的差异导致结球生菜南北两边的长势都不均匀,不同品种生菜产量由南向北呈现出较为一致的规律性,即北边产量高于南边,靠近棚边最南边的位置与其他区域生菜产量存在显著差异。试验研究温室不同种植位置的温光等环境条件变化规律,为温室蔬菜科学化种植提供了理论依据。     

水苏糖提取鲜基草食蚕贮藏适宜温湿度和贮藏期研究

以水苏糖提取的原料草食蚕为材料,研究不同温湿度条件下贮藏,对草食蚕品质和水苏糖含量的影响。分别设置空气相对湿度为50%~60%,60%~70%,70%~80%,80%~90%;温度设置为0℃,4℃,8℃,12℃。结果表明：随着贮藏温度对失重率、霉变度、水苏糖含量都有极显著影响(p<0.01),随温度降低,失重率、霉变度、水苏糖损失均降低,贮藏湿度对失重率、霉变度也有极显著影响,随湿度增加,失重率减少、霉变度增加。在研究温度范围内,贮藏适宜湿度为70%~80%。贮藏温度为0℃时草食蚕可贮藏10个月以上,4℃时可贮藏期6个月,8℃时贮藏4个月,12℃时可贮藏2个月     

水稻边际优势利用栽培增产的生态原因研究

对大小垄栽培群体和30cm等行距栽培群体不同层次的光照强度、群体行间温、湿度等生态因子及每穴穗数、每穗实粒数和单穴生产力三个产量性状和不同分蘖时期每穴茎数的边际效应指数进行了研究。结果表明,大小垄栽培群体下部的光照强度和透光率显著增加,行间温、湿度降低,使群体内部的光、温条件得到改善。每穴穗数、每穗实粒数和单穴生产力及不同分蘖时期每穴茎数的边际效应指数降低,说明实行大小垄种植后,群体内部的长势与边行的差距缩小,群体内部个体的生长优势得到发挥,达到了利用边际优势增产的目的。     

水稻边际优势利用栽培增产的生态原因分析

对大小垄栽培群体和30cm等行距栽培群体不同层次的光照强度、群体行间温、湿度等生态因子及每穴穗数、每穗实粒数和单穴生产力三个产量性状和不同分蘖时期每穴茎数的边际效应指数进行了研究。结果表明,大小垄栽培群体下部的光照强度和透光率显著增加,行间温、湿度降低,使群体内部的光、温条件得到改善。每穴穗数、每穗实粒数和单穴生产力及不同分蘖时期每穴茎数的边际效应指数降低,说明实行大小垄种植后,群体内部的长势与边行的差距缩小,群体内部个体的生长优势得到发挥,达到了利用边际优势增产的目的。     

A Study Transient on Predictive Calculation Method of on Underground Ventilation Network

The authors developed a computer program of transient predictive calculation method on underground ventilation network. The program approximated a field data set of seasonal cyclic changes of air Temperature and humidity at the inlet to the sine curves, and included sensible heat conduction from rock to air current. The temperature of rock around and airway was calculated by finite difference method. The prediction method can be used to calculate the variation of flow rates, temperatures and humidities of air flow in the airways along underground network.     

Effects of desiccation and a change in temperature on germination of immature grains of wheat (Triticum aestivum L.)

A study was made of the effects of desiccation and a change in temperature on the germination of wheat grains harvested 20 days after anthesis. When the germination test was performed immediately after harvesting, germination percentages ranged from 5.2% to 10.7%. Germination percentages increased to 48.2% to 90.3% after grain had been desiccated at 20 °C and then hydrated at 10 °C. This increase occurred even if grains had been desiccated in an atmosphere of high relative humidity. The germination percentage of non-desiccated grains depended on the germination temperature. When the pericarp and testa were removed from embryos, the germination percentage of grains incubated at 20 °C and then at 10 °C was higher than that of grains incubated at 10 °C. In general, a low germination temperature is believed to be effective in breaking dormancy of wheat grains. However, a change in temperature stimulated germination to a greater extent than a constant low temperature. The germination percentage of 5-day cycle alternating temperature was greater than that with 1-day, 2-day and 10-day cycles. Although the germination of immature wheat grains was stimulated by both high and low germination temperatures, it is likely that cycles shorter and, also, longer than a critical period induce limited germination. Loss of dormancy commonly occurs when development of wheat grains proceeds at a high temperature, with imbibition at a low temperature. However, germination ability of non-desiccated immature wheat grain was enhanced by a change in temperature during germination. This revised version was published online in August 2006 with corrections to the Cover Date.     

沙尘天气下大气电场与颗粒物关系研究

大气电场对各种气象要素的变化有着敏锐的反应,对一个地区大气电场特征的研究,有助于分析各种相关的天气过程,对该地区气候特征的研究也有重要意义。本文给出了太原地区3次沙尘天气下2个气象站内大气电场与大气颗粒物以及风速、湿度等气象要素相关性进行分析。结果表明,沙尘与晴天天气的大气电场有较大的差别,当沙尘到来后,大气电场值迅速下降,并且始终保持为较大的负值;沙尘天气下大气电场、PM10、PM2.5都发生剧烈的变化,PM1.0变化相对较小,其中沙尘天气下大气电场的绝对值、PM10、PM2.5分别比晴天天气下的值高3.94~5.74、2.07.94~5.89、1.28~5.91倍,沙尘天气下的PM1.0比晴天降低0.25~0.75倍）。不同粒径颗粒物的起电机理以及颗粒物来源不同导致颗粒物与大气电场的相关性不同,其中PM10、PM2.5呈较高的正相关,PM1.0呈负相关,且相关性较低。由于郊区站与城市站的下垫面不同,较大的风速将郊区站地表较大粗粒子吹起,使得郊区站沙尘大气电场在一些时段内会出现正值。     

冬季稳定人工环境实验室内温度的新方法

人工环境实验室对温度的控制精度低于工艺性环境要求,但冬季若采用分体式空调制热模式控制,实验室温度的波动范围过大,影响采集实验数据的准确性。提出冬季采用空调制冷模式联合电取暖器稳定人工环境实验室内温度的新方法,在背景实验中将新方法和传统空调制热温度控制方法进行对比,结果表明：采用新方法能大幅度提高人工环境实验房间温度的稳定性。为对新方法中空调的设定制冷温度与电取暖器功率匹配问题做进一步研究而进行探究试验,实验结果表明：空调制冷量Q₁、测试房间热负荷Q₂、电取暖器功率Q₃和测试房间其他设备功率Q₄存在匹配关系,当空调设定温度相同时,|Q₁+Q₂-Q₃-Q₄|值越小,人工环境实验室内温度波动频率越稳定,振幅越小。     

Properties of Temperature Difference Self-power Adjusting Valve Used in Blast Furnace

Blast furnace campaign life has a great effect on technical and economical indexes of ironmaking production. Cooling condition and life-span of cooling apparatus have a great influence on campaign life of blast furnace. Owing to constant flux water supply used for blast furnace cooling at present, cooling intensity doesn't meet the demand of heat load in peak value, concurrently, cooling water supply lacks equilibrium and stability, which will cause burnout of cooling apparatus and diminution of blast furnace campaign life. So temperature difference self-power adjusting valve is introduced to make BF cooling apparatus change constant flux water supply mode to constant temperature difference water supply mode in order to satisfy the need of cooling intensity when heat load wis in peak value.Principle, structure ,properties and function of temperature difference self-power adjusting valve are explained. The flux in different temperature is measured.     

Nitrogen reduction stimulated by a three-dimensional electrochemical-biofilm reactor and its correlation with electric field

To realize automatic control, it is important to study the response of reactor to electric field. A three-dimensional biofilm eletrode reactor is developed and steadily operated to remove nitrogen. In the reactor, oxygen is produced on the anode and hydrogen is produced on the cathode of the three-dimensional electrode by electrolysis water. Microorganism in the reactor utilize oxygen and hydrogen adequately to remove nitrogen by nitrification-denitrification. To evaluate the correlation of electric field with the reactor, DO, pH and nitrogen removal efficiency are studied. Results show that when a electric field of 0.013 4 mA/cm 2 is applied to the system, the removal rate of NH +4-N, NO -3-N and TN is 90%, 70% and 70%, respectively. To assure the reactor run efficiently, the maximum of the intensity of electric field applied to the reactor is 0.0201 mA/cm 2. Within 0.0201 mA/cm 2, the system is in stable running status, while DO and pH is altered resulting from the intensity of electric field. With enhancing the intensity of electric field, the removal rate of NO -3 -N can be improved, although, the removal rate of NH +4-N is not elevated markedly. There is no accumulation of NO -2 -N within 0.0201 mA/cm 2.     

The effect of temperature on seed set and embryo development in reciprocal crosses of wheat and barley

Summary The effect of temperature on seed set and embryo development in reciprocal crosses of barley and wheat was assessed in crosses involving two spring barley varieties (Betzes, Martonvásári 50) and one wheat variety (Chinese Spring). Detached tillers placed in nutrient solution were pollinated in controlled environments at constant day-night temperature regimes (12, 15, 18 and 21° C) with a light intensity of 30,000 lux and a relative humidity of 80%. When barley was used as the female, lower temperatures (12 and 15° C) produced the maximum seed set, whereas for the reciprocal cross, the highest temperature (21° C) produced the best seed set in the Chinese Spring × Betzes combination.Low temperature retarded the embryo development. The highest numbers of hybrid plants were produced at 18° C and 21° C in the barley × wheat cross and in the wheat × barley cross, respectively. Embryos of about 1.5 mm length in the barley × wheat cross, and of about 1.0 mm length in the wheat × barley cross germinated successfully. The smallest embryo giving rise to hybrid plants was 0.57 mm in the barley × wheat cross and 0.51 mm in the wheat × barley cross.     

Influence of environmental conditions on the quality attributes and shelf life of ‘Goldfinger’ bananas

‘Goldfinger’ bananas (Musa accuminata, FHIA-01) were harvested, held for 14–22 d at five temperatures and a constant relative humidity (RH) or at five RHs and a constant temperature and evaluated for quality attributes. The objectives of this work were to: (1) create quality curves for bananas stored at chilling and non-chilling temperatures; (2) create quality curves for bananas stored at a non-chilling temperatures and different RHs; (3) identify which sensory quality attribute limits the shelf life and marketability of bananas when stored at chilling and non-chilling temperatures or at different RHs; and (4) correlate subjective sensory attributes with quantitative quality measurements. Results from this study showed that temperature had a more significant impact on the quality of banana than RH. Bananas stored at temperatures higher than 10 °C were yellower and softer but had lower starch and higher soluble solids and total sugar content than those stored at lower temperatures. When stored at 2, 5 and 10 °C, bananas developed chilling injury (CI) and abnormal ripening when transferred to 20 °C. The most remarkable impact of RH on banana quality was on weight loss, which was significantly higher in fruit held below 80% RH than in fruit held in 87 or 92% RH. CI was the first sensory quality attribute to reach the limit of acceptability in fruit stored at 2, 5 and 10 °C, whereas color changes and softening limited the shelf life of bananas stored at 15 and 20 °C. Changes in color and/or softening were the two main sensory attributes that limited the shelf life of bananas stored at different RHs. Overall, for maximum quality and shelf life bananas should be stored at or above 15 °C and 92% RH. Finally, sensory attributes can be used to estimate peel color, pulp softening and sweetness, while SSC can be used as a reliable and simple method to estimate the total sugar content of bananas stored at different temperatures or different RHs.