基于EWT-KMPMR组合模型的光伏电站短期功率预测

为提高光伏电站短期功率预测的精度,提出一种基于经验小波变换(empirical wavelet transform,EWT))和核最小最大概率回归机(kernel mini max probability machine regression,KMPMR)的组合预测模型,对晴天、阴天和雨天3种天气类型下的光伏电站出力分别进行了预测分析。该文首先采用EWT将相似日光伏功率序列分解为具有特征差异的AM-FM分量,然后根据各AM-FM分量的变化特点建立相应的KMPMR预测模型分别进行预测并叠加得到最终预测结果。试验结果表明,相比SVM方法,该文方法在晴天、阴天和雨天可提高预测精度(MAE)分别为56.19%、54.15%和76.33%;相比EMD-KMPMR方法,在降低近一半左右计算规模的同时,可提高预测精度(MAE)分别为9.42%、38.74%和64.52%。以阿克苏地区光伏电站实际运行数据进行试验验证表明,该文方法在3种天气类型下均可取得较高的预测精度。     

电站尾水渠内鱼道进口位置布局

电站尾水渠是上溯鱼类较为理想的聚集场所,利用电站尾水渠合理布置鱼道进口,是目前大中型河流鱼道建设中的研究热点之一。该文通过数值模拟,结合鱼类游泳能力,对利用电站尾水诱鱼的鱼道进口布置进行研究。结果表明:机组运行方式、鱼道进口位置与出流方向均对鱼道进口诱鱼水流产生较大影响。机组运行方式决定了尾水渠内主流的位置,并在主流两侧形成多个回流区。回流区水流的旋转方向和位置对鱼道进口诱鱼水流的影响较大,鱼道进口的诱鱼水流动量较小,其出流方向应与回流区水流方向一致,并可根据电站运行方式,设置多个鱼道进口。主流与回流区之间的过渡区域是布置鱼道进口的重点区域。该研究结果可为优化改进大中型河流鱼道进口设计提供重要参考。     

质地对土壤热性质的影响研究

土壤热性质是水热迁移研究中的重要参数之一。根据非稳态条件下热流方程的差分解和实测土壤温度资料计算了不同质地土壤的热扩散率，并得出了质地影响下的土壤导热率关系式。研究结果表明，对特定土壤而言，土壤导热率与含水率之间可建立幂函数关系；砂粒、粉粒和粘粒含量对土壤热性质有不同程度的影响；不同质地土壤的热性质与土壤水吸力之间存在良好的定量关系；此外，含盐土壤的导热率可表示为浓度的幂函数关系。     

Impact of thermal power plant emissions on vegetation and soil

Studies were made to assess the impact of a thermal power plant located at Obra on vegetation and soil in surrounding areas. Pollutant concentration in the area gradually decreased along a belt in the prevailing wind direction and a gradient of structural and functional changes in plants and soil was observed. Natural vegetation in the area varied significantly at different sites and on the basis of plant responses can be classified as insensitive, intermediate and sensitive.

The effect of the power plant emissions on soil and eco-physiological characteristics such as pH, organic matter and N, P, K and S concentrations in soil; leaf injury symptoms, number and distribution of plant species; chlorophyll content in leaves, percentages of photosynthetically active leaf area; accumulation of N, P, K, and S in leaves etc. seemed to be a function of the pollutant gradient existing in the area. There was a relationship between plant responses and changes in the chemical factors of soil and plants due to pollution. This study indicates possible elimination of plant species, first the trees then the shrubs and lastly the herbs and grasses from the environs of the thermal power plant. The increase in soil acidity in the area may cause cation-anion imbalance and microbe population reduction to affect soil fertility.

     

复水对海水浇灌的玉米幼苗根系补偿效应的影响

为了在沿海地区利用海水补充浇灌技术实现作物的安全节水灌溉,从而节约农业用水,以抗性玉米品种"农大108"为材料,研究了先用不同浓度海水处理组分别浇灌玉米幼苗,再用清水浇灌,然后用聚乙二醇(PEG-6000)模拟干旱胁迫的过程中根系补偿特性的变化。结果表明,复水前25%海水持续浇灌组和25%海水和50%海水交替浇灌组处理中,根系脯氨酸含量及超氧物歧化酶活性明显增加,可溶性糖及K+含量、根系活性及相对含水率、根冠比缓慢上升,丙二醛含量减少;复水后,根系K+含量、根系活性及相对含水率明显上升,而其他指标呈现下降的趋势;干旱模拟期间,根系活性及丙二醛含量略微下降,其他指标急剧升高。与清水灌溉组相比,50%海水持续胁迫对根系造成损伤使得复水补偿代谢显著降低,25%海水持续浇灌组的补偿能力略微下降,25%海水和50%海水交替浇灌组复水补偿效应略微或明显增强。因此,经过适宜浓度的海水胁迫诱导后,根系发生适应性代谢,然后复水,根系的物质代谢及抗旱性可以产生补偿甚至超补偿效应,同时也缓解了盐渍对植物的次生胁迫效应。     

Influence of thermal processing on the allergenicity of peanut proteins

Peanuts are one of the most common and severe food allergens. Nevertheless, the occurrence of peanut allergy varies between countries and depends on both the exposure and the way peanuts are consumed. Processing is known to influence the allergenicity of peanut proteins. The aim of this study was to assess the effect of thermal processing on the IgE-binding capacity of whole peanut protein extracts and of the major peanut allergens Ara h 1 and Ara h 2. Whole proteins, Ara h 1, and Ara h 2 were extracted and purified from raw, roasted and boiled peanuts using selective precipitation and multiple chromatographic steps, and were then characterized by electrophoresis and mass spectrometry. The immunoreactivity of whole peanut extracts and purified proteins was analyzed by the enzyme allergosorbent test (EAST) and EAST inhibition using the sera of 37 peanut-allergic patients. The composition of the whole protein extracts was modified after heat processing, especially after boiling. The electrophoretic pattern showed protein bands of low molecular weight that were less marked in boiled than in raw and roasted peanuts. The same low-molecular-weight proteins were found in the cooking water of peanuts. Whole peanut protein extracts obtained after the different processes were all recognized by the IgE of the 37 patients. The IgE-binding capacity of the whole peanut protein extracts prepared from boiled peanuts was 2-fold lower than that of the extracts prepared from raw and roasted peanuts. No significant difference was observed between protein extracts from raw and roasted peanuts. It is noteworthy that the proteins present in the cooking water were also recognized by the IgE of peanut-allergic patients. IgE immunoreactivity of purified Ara h 1 and Ara h 2 prepared from roasted peanuts was higher than that of their counterparts prepared from raw and boiled peanuts. The IgE-binding capacity of purified Ara h 1 and Ara h 2 was altered by heat treatment and in particular was increased by roasting. However, no significant difference in IgE immunoreactivity was observed between whole protein extracts from raw and roasted peanuts. The decrease in allergenicity of boiled peanuts results mainly from a transfer of low-molecular-weight allergens into the water during cooking.     

日光温室保温被卷放位置对温度环境的影响

温室保温被卷放位置影响着室内的太阳能得热及通过前屋面的散热,从而影响着温室温度。该研究以室外气象因子为模拟输入条件,分别模拟晴天、阴天不同保温被卷放位置对12 m跨度日光温室温度环境的影响。保温被卷放位置分别为保温被卷至前屋面一半与至顶2种方案。模拟结果显示：白天保温被卷至前屋面一半的室内空气温度高于保温被卷至屋顶的温度,而夜间2种方案室内空气温度差异不明显;晴天保温被卷至屋顶与卷至前屋面一半相比,可明显提高夜间墙体表面温度,但对后坡的夜间表面温度影响较小。该研究结果对温室生产中晴天、阴天保温被卷的合理放     

Deposition around a coal-fired power station during a wintertime precipitation event

The contribution to local wet deposition of emissions from a coal-fired power station at Inkoo on the south coast of Finland has been investigated during a wintertime precipitation event. Making use of intensive radiosonde and weather radar observations of meteorological factors, concentrations of sulphur in deposition due to plume washout were predicted by a short-range deposition model. The model used the scavenging coefficient to parametrize the wet removal of pollutants, and it took into account the wind drift of falling precipitation particles within the plume. The model predictions were then compared with the chemical analysis results from snowfall samples collected within 10 km of the power station during the experiment.The experiment was performed ahead of a deeply-occluded front during a period with strong advection of long-range transported pollutants. No reliable sign of the influence of the power station on the sulphate deposition could be identified. On the other hand, the deviations of acidity from the mean pH-value of 4.1 were concentrated in one sector near the expected area of deposited plume pollutants. If local emissions were responsible for these deviations, the explanation may lie in a slightly incorrectly estimated plume direction or the effects of alkaline fly ash. Nevertheless, definite conclusions cannot be drawn, because only a few collectors happened to be sited in the modelled sector of plume washout and none in its maximum area.     

生物质电厂飞灰用作肥料的可行性评价

为了研究炉排燃烧生物质电厂飞灰在农林方面的应用价值和可能产生的环境影响,根据欧盟相关标准分析了2种飞灰(A、B)的基础特性(水分、灰分、总有机碳含量、p H值和电导率),并利用电感耦合等离子体光谱仪、质谱仪分析了飞灰中营养元素和有害元素的含量;参考中国固体废物浸出毒性浸出方法标准研究了营养元素和有害元素的浸出特性。结果表明,2种飞灰p H值均大于12,呈较强的碱性;并且二者不仅含有较高浓度的有机碳(A:18.39%;B:7.79%),还富含K、Ca、Mg、P等营养元素,其他主要有害元素的含量低于欧盟一些国家生物质灰农、林用和中国粉煤灰农用标准所规定上限值,这使得它们可以作为土壤改良剂或者辅料应用的农林方面。此外,除A飞灰中Cr的浸出率为1.274%外,其他有害元素的浸出率远小于1%,因而当它们应用在农林土壤时不至于造成污染。     

泵站正向进水前池扩散角对池内流场结构的影响

针对从多沙河流取水的大型泵站进水前池内水流流态较差,易在池内产生大尺度回流区域,导致泥沙严重淤积等问题,该研究以甘肃省景泰川电力提灌工程典型泵站的正向进水前池为研究对象,构建不同扩散角体型结构的正向进水前池三维模型,基于Mixture多相流模型和Realizable k-ε模型开展数值模拟计算,阐明了正向进水前池流场结构特征,提出了有效改善正向进水前池流场结构的扩散角范围。结果表明：泵站机组全开时,正向进水前池内流场结构对称分布,在进水前池中央形成主流区,两侧形成回流区,中央主流区域水流流速远大于两侧回流区,主流效应显著;随着扩散角的减小,两侧低流速区面积减小,主流区域流速呈下降的趋势,区域宽度呈现增加的趋势,进入前池的水流扩散效应增加明显;扩散角在25°～30°之间时,入池的水流沿流程发展和扩散较为充分,有效改善多泥沙河流引水泵站前池的泥沙淤积,研究成果可为同类泵站的设计和更新改造提供指导和参考。     

热开关控制光伏/温差联合发电装置设计提高发电效率

为解决光伏电池板接收太阳辐射发电时板面温度上升导致光电转换效率下降的问题,该文通过温差发电技术对光伏电池板进行主动冷却;同时为解决温差发电技术因温差较小时热电转换效率低下的问题,引入热开关对装置进行控制,并采用扁平热管作为传热单元,利用水对流为系统进行冷却。为测试基于热开关的光伏/温差联合发电装置的性能,分析了不同光辐射强度、不同板面温度、以及不同冷端温度对系统的影响,并搭建试验平台,对联合发电装置进行试验研究。结果表明,装置联合发电效率高于单独一种发电方式的效率,实现了能量的梯级利用。在对装置进行瞬时性能测试期间,发电效率最高达到19.45%,发电功率最大达到32.15 W。在6 d全天性能测试期间,联合发电装置的平均发电效率为17.72%,最高可达18.37%。所获电能基本可以满足农业温室大棚检测系统、远程传感器的供电要求。     

Effects of industrial effluents on local cloudiness and rainfall

Industrial effluents alter both the microphysical properties that regulate the rate of production of precipitation and the location and strengths of density and velocity perturbations that regulate the dynamical development of clouds. Therefore, physical mechanisms exist through which industrial activities can modify local weather elements such as cloudiness and rainfall. Snow falling from large cooling tower plumes and the cloudiness spawned by heat rejection are the most obvious manifestations of this control. The extent to which industrial effluents exert control over local weather and climate remains controversial and difficult to quantify. As industrial activity becomes more concentrated, anomalous weather effects could become a problem that will require consideration when planning new facilities. This is particularly true for processes that modify the dynamical properties of the atmosphere by rejecting heat directly to the atmosphere.     

Beryllium pollution from slag and ashes from thermal power stations

Beryllium enters the environment principally from coal combustion. Be contents in the ashes from a Czechoslovak power plant were determined. The ashes used in the experiment were as follows: coarse (> 2.0 mm) and fine (2.0 to 0.2 mm) fraction from dump, and fine (< 0.2 mm) fraction from electrostatic precipitators. It was discovered that the acidic and the alkali aqueous extracts of these ashes contain various concentrations of Be (1 to 17% of total concentration). Wastewater has shown 3.15 and 3.4 μg Be L^?1. Thus, secondary long-term Be pollution emerges from the slag and ash dumps.     

灰尘对全玻璃真空太阳集热管热性能的影响(简报)

全玻璃真空太阳集热管外部灰尘的累积会导致真空管集热性能不断降低,为了确定灰尘对全玻璃真空太阳集热管的影响,该文从累计太阳辐射与真空管连接水箱温差关系入手,首先对水平和倾斜45.安装的真空管各两根进行30d的闷晒.后对水平、倾斜管其中各一根进行除尘处理,随后将真空管分别以30°,42°,45°和50°倾斜安装,经过30 d的闷晒后,不做任何处理.研究结果表明,在相同的累计辐射下,除尘管最终得热量几乎不变,而未除尘水平、倾斜管则分别下降了0.98×104J和5.24×104J,各占其总得热量的2.11%和10.25%,说明灰尘对倾斜真空管影响较水平真空管更为显著;30 d闷晒后,30°,42°,45°和50°倾斜安装真空管最终得热量分别下降了13.8×104,4.91×104,5.90×104和6.22×104J,各占初次测量总得热量的29.83%,10.99%,12.75%和11.90%,经假设检验后可知灰尘对30°安装真空管影响最为显著,其次分别为50°,45°和42°真空管.     

基于农村分布式光伏电站勘测的小型无人机倾斜摄影系统及试验

建设农村分布式光伏电站前需要人工消耗大量时间攀爬屋顶勘测尺寸,勘测人员生命安全也缺乏有效保障。针对该问题该研究开发了一款可以快速搭载的小型无人机五相倾斜摄影相机ZTRS-M5B,相比于其他倾斜相机,ZTRS-M5B拥有更好的便携性和更低的制作成本。使用搭载ZTRS-M5B的无人机倾斜摄影系统分别对建有分布式光伏电站的农村居民住宅区和工厂区域进行三维建模,并与地面人工实测值进行比较来检验模型精度。结果表明光伏电站太阳能板的模型倾角和实际倾角高度相关,房屋建筑的模型水平尺寸平均绝对误差为0.11 m,平均相对误差为0.37%,模型垂直尺寸平均绝对误差为0.12 m,平均相对误差为1.04%,精度上满足农村分布式光伏电站建设前期勘测要求,证明该系统也能够替代其他倾斜摄影系统对中小区域范围进行快速勘测。     

积灰和光照强度对光伏组件输出功率的影响

针对农业光伏设备积灰严重导致发电量降低的问题,该文采用人工布灰的室内试验方式,利用太阳能全自动模拟跟踪装置,研究灰尘粒径、积灰密度和光照强度对光伏组件输出功率的影响规律,建立了输出功率减小率预测模型,并在室外自然光照下进行模型验证。结果表明:光伏组件输出功率减少率随积灰密度的增大而增大,但增长速度逐渐变缓;当积灰密度相同时,光伏组件输出功率减小率随灰尘粒径的增大而减小,当光照强度为18 300 lux、积灰密度为10 g/m2时,0～38、38～75、75～110和110～150μm粒径组对应输出功率减小率分别为15.96%、12.51%、8.16%和5.39%。双因素方差分析结果表明,灰尘粒径、积灰密度及两者交互作用对输出功率减小率影响显著,光照强度对输出功率减小率影响不显著。通过理论分析,提出了基于遮挡效果相同的不同颗粒级配灰尘的等效粒径的概念和计算公式,进一步利用多项式拟合,建立了光伏组件输出功率减小率随积灰密度和等效粒径变化的计算模型(R2=0.986)。利用太阳能水肥一体化装置对计算模型进行验证,误差绝对值均小于1.5%,表明模型具有很好的实际应用价值。该模型可为光伏农业设备中供电系统的优化配置提供设计依据。     

Influence of thermal treatment on black currant (Ribes nigrum L.) juice aroma

The influence of thermal treatment on black currant juice aroma was investigated in temperature and time ranges relevant for black currant juice concentration processes, namely, 45, 60, 75, and 90 degrees C. Forty-nine aroma compounds were quantified, and the thermal treatment resulted in concentration increases of most terpenes, aldehydes, furans, and phenols, whereas the concentration of esters slightly decreased. Higher temperatures and longer exposure times had larger effects on the aroma compounds. Odor triangle tests showed no sensory difference between pasteurized juice and juice heated at 60 degrees C, whereas juice heated at 90 degrees C differed significantly from pasteurized juice. It is concluded that a 90 degrees C thermal treatment of black currant juice, which is in the temperature range used for conventional evaporation of black currant juice, has an effect on the aroma and sensory properties.     

动力电池冷热双向循环热管理系统性能分析

基于工质相变换热和无泵循环思路,提出了一种动力电池冷热双向热管理系统。以某款三元锂电池为研究对象,试验测试了冷热双向循环热管理系统的散热和加热工况。结果表明：该系统能实现电池箱低温工况加热与高温工况散热的运行切换管理。散热工况下,换热板采用4根竖管比单根蛇形管的散热能力强;冷凝器侧强制风冷散热与自然对流散热相比,能将系统一换热功率提高10%～44.2%,系统二换热功率提高20%～48.6%;电池箱温度为60 ℃时,自然对流散热系统换热板的最大温差小于2 ℃,强制对流散热系统换热板的最大温差小于1 ℃;在电池初始温度25 ℃时,1C、2C、3C放电倍率下,放电结束强制对流散热在能将8块电池的平均温度分别降低2.1、3.9、4.7 ℃。加热工况下,多组试验电池箱的升温效果一致性较好。考虑车辆行驶中换热板倾斜的影响,受制于工质的流量分配,散热工况时温度均匀性优于加热工况。     

Effects of effluents from a sewage treatment plant on the aquatic organisms

The effects of sewage pollution on the distribution and abundance of some orgnanisms over a period of 4 mo at the Ahmadu Bello University Main Campus sewage treatment plant and Kubanni river were studied. Physico-chemical parameters such as dissolved oxygen; temperature; hydrogen ion concentration (pH); electrical conductivity and chemical oxygen demand influenced by pollution were measured with respect to the population of aquatic organisms. The organisms were used as biological indices to monitor the ecological imbalance caused by the effluent. The variations in concentrations of some heavy metals were also measured. The studies revealed that at the source of pollution there were no organisms except for some insect larva such as Eristalis, Psychoda, and some microscopic algae like Oscillatoria, Anaebaena, and Polysystis. A location (site 5) on Kubanni river just before the confluence of the sewage effluent and the river was taken as the control. There was a wide variety of organisms (crustaceans, rotifers, and fish) at the control point.     

Influence of thermal treatments simulating cooking processes on the polyphenol content in virgin olive oil

Virgin olive oils were subjected to simulated common domestic processing, including frying, microwave heating, and boiling with water in a pressure cooker. The impact of these processes on polyphenol content and physicochemical characteristics of oils was assessed. Thermal oxidation of oils at 180 degrees C caused a significant decrease in hydroxytyrosol- and tyrosol-like substances. In contrast, oils heated for 25 h still retained a high proportion of the lignans 1-acetoxypinoresinol and pinoresinol. Thermal oxidation also resulted in a rapid degradation of alpha-tocopherol and the glyceridic fraction of oils. Microwave heating of oils for 10 min caused only minor losses in polyphenols, and the oil degradation was lower than that in thermoxidation assays. Again, lignans were the least affected polyphenols and did not change during microwave heating. Boiling a mixture of virgin olive oil and water in a pressure cooker for 30 min provoked the hydrolysis of the secoiridoid aglycons and the diffusion of the free phenolics hydroxytyrosol and tyrosol from the oil to the water phase. Losses of polyphenols were detected only at pH lower than 6. Moreover, alpha-tocopherol and the glyceridic fraction of oils were not modified during this process. It is worth noting that all the heating methods assayed resulted in more severe polyphenols losses and oil degradation for Arbequina than for Picual oil, which could be related to the lower content in polyunsaturated fatty acids of the latter olive cultivar. These findings may be relevant to the choice of cooking method and olive oil cultivar to increase the intake of olive polyphenols.