高致病性禽流感与天气条件分析

利用全国气象观测资料、NCEP／NCAR日平均再分析数据资料集和我国高致病性禽流感疫情资料,分析高致病性禽流感发生的时空特征以及与天气条件的关系。结果表明,我国高致病性禽流感全年可以发生,疫情的分布范围广,大部分地区都有出现。发生和传播与环境气象条件有关,季节性明显,冬季和秋季为主要发病季节。冬季禽流感发生前高空500hPa以槽为主,冷空气活动频繁。发生日基本在高压系统的控制之下,地面流场呈辐散状,风速稳定少变。     

2012～2013安徽省空气质量对比及原因分析

根据安徽省环境保护局提供的2012～2013年空气污染指数（API）资料,对安徽省各地市空气质量级别、首要污染物等指标和空气污染指数的月、年均值进行了全面的统计分析及横向、纵向对比,得出安徽省空气污染的时空分布规律,并从多方面分析造成其规律变化的成因.结果表明,2013年安徽省API年均值、高值城市数量均显著高于2012年;安徽省空气质量以优良为主,2013年优良天数比例明显下降,Ⅲ1级污染以上天数也明显增加,出现V级污染的城市增加至7个,地域也扩大至安徽东南部;首要污染物以PM10为主,铜陵SO2污染相对严重.安徽省逐月的API分布有明显的时间、空间差异,API高值期有1、6及10 ～ 12月,整体上淮北＞江淮＞江南,东部＞西部;API高值期有明显的北高南低的逐降形势,区域间差值较大;API低值期则存在中东部偏高,南北相对偏低,区域间差值较小.安徽省各地市的GDP构成、人口结构对API起到基础性贡献,而6月小麦秸秆焚烧期及10月水稻-玉米秸秆混合焚烧期造成PM10浓度急剧增加,对API起到高峰推动作用,安徽省地形也起到平原扩散、山区阻挡堆积的作用.     

乌鲁木齐市南山小渠子中药种植基地环境的综合评价

[目的]通过对乌鲁木齐市南山小渠子林场的土壤、大气、灌溉水等环境质量进行分析评价,为中药材GAP种植基地建设提供依据。[方法]参考国家环保局《环境监测分析方法》采样,土壤质量按《土壤环境质量标准）GB15618—1995进行检测;灌溉水质量按《农田灌溉水质标准}GB5084—2005进行检测;空气质量监测采用《环境空气质量标准））GB3095—1996及其分析方法进行分析。[结果]乌鲁木齐市南山小渠子中药材种植基地土壤质量达到国家二级标准;灌溉水质量达到国家旱作标准;空气质量达到国家一级标准。[结论]新疆乌鲁木齐市南山小渠子中药材种植基地环境质量良好;达到并超过GAP种植相关要求,可作为中药材规范化种植基地。     

板栗气体射流冲击干燥特性和工艺优化

为了解决板栗深加工中的干燥问题,将气体射流冲击干燥技术应用于板栗干燥,研究了板栗仁在不同风温（70、75、80和85℃）和风速（10、12、14和16 m/s）下的干燥特性;根据单因素试验结果进行了风温、风速和预处理（不烫漂、100℃热水烫漂和100℃蒸汽烫漂）的正交试验。试验结果表明：板栗的整个干燥过程属于降速干燥,风温和风速对板栗的干燥速率均有显著影响,但风温对其的影响比风速更为突出;正交试验各因素对明亮度、蓝黄值和感官评分的影响顺序为：预处理＞风温＞风速,对缩短板栗干燥时间的影响顺序为：风温＞风速＞     

Maximum slat width for cooling efficiency of horticultural produce in wooden crates

The influence of wood package design on airflow distribution was investigated for forced-air cooling using horticultural produce simulators. The position of grooves on the container walls was tested using slat width of 100–200 mm and airflow rates ranging from 0.0005 to 0.003 m³ kg⁻¹ s⁻¹. The package opening configurations were compared based on their impact on the energy added to the system using a methodology previously developed. For this purpose, apples and sweet corns were taken as examples of produce from two different extremes in the respiration activity range. For airflow rates as low as 0.0005 m³ kg⁻¹ s⁻¹one groove at the bottom of the container produced a cooling process more uniform than the other one-groove configurations and even two grooves because of natural convection effect. If packing low respiration rate produce, increasing airflow rate could compromise the process energy efficiency because of air circulation obstruction for less vented containers. For high respiration rate produce enlarging open area above 2.4% would be recommended rather than increasing airflow rate to enhance cooling energy efficiency.     

Oribatid mites in urban zones of West Berlin

Summary A comparison is made between oribatid fauna (Acari, Oribatida) in the urban regions of West Berlin and forest areas. There are characteristic species compositions living in urban soils, in epilithic moss cushions or on the bark of trees. The urban environment obviously causes a change in the species pattern in these types of habitats and minimizes the number of species in central urban regions. The most important regional factors are probably relative aridity, air pollution and habitat isolation, showing a similar increasing tendency from sub-urban to central regions of West Berlin. The effects of air pollution (SO2) on moss-inhabiting oribatid mites are analysed in 13 sites of the urban district of West Berlin. The use of moss- and bark-dwelling mites as bioindicators of air pollution is discussed.Soil oribatids might be useful bioindicators of soil pollution in further research.Dedicated to the late Prof. Dr. M.S. Ghilarov     

Modern forestry vehicles and their impacts on soil physical properties

“Close-to-nature forest stands” are one central key in the project “Future oriented Forest Management” financially supported by the German Ministry for Science and Research (BMBF). The determination of ecological as well as economical consequences of mechanized harvesting procedures during the transformation from pure spruce stands to close-to-nature mixed forest stands is one part of the “Southern Black Forest research cooperation”. Mechanical operations of several typical forest harvesting vehicles were analysed to examine the actual soil stresses and displacements in soil profiles and to reveal the changes in soil physical properties of the forest soils. Soil compaction stresses were determined by Stress State Transducer (SST) and displacement transducer system (DTS) at two depths: 20 and 40 cm. Complete harvesting and trunk logging processes accomplished during brief 9-min operations were observed at time resolutions of 20 readings per second. Maximum vertical stresses for all experiments always exceeded 200 kPa and at soil depths of 20 cm for some vehicles and sequences of harvesting operations approached ≥500 kPa. To evaluate the impacts of soil stresses on soil structure, internal soil strengths were determined by measuring precompression stresses. Precompression stress values of forest soils at the field sites ranged from 20 to 50 kPa at soil depths of 20 cm depth and from 25 to 60 kPa at soil depths of 40 cm, at a pore water pressure of −60 hPa. Data obtained for these measured soil stresses and their natural bearing capacities proved that sustainable wheeling is impossible, irrespective of the vehicle type and the working process. Re-occurring top and subsoil compaction, increases in precompression stress values in the various soil horizons, deep rut depths, vertical and horizontal soil displacements associated with shearing stresses, all affected the mechanical strengths of forest soils. In order to sustain naturally “unwheeled” soil areas with minimal compaction, it is recommended that smaller machines, having less mass, be used to complete forest harvesting in order to prevent or at least to maintain currently minimal-compacted forest soils. Additionally, if larger machines are required, permanent wheel and skid tracks must be established with the goal of their maximum usefulness for future forest operations. A first step towards accomplishing these permanent pathways requires comprehensive planning with the Federal State Baden-Württemberg. The new guideline for final opening with skid tracks (Landesforstverwaltung Baden-Württemberg, 2003) proposes a permanent skid track system with a width of 20–40 m.     

机械式空气整根钵苗移栽器的研究

空气整根钵苗全自动移栽机的核心部件是移栽器。采用机械方式完成全自动移栽机的送秧和投苗，简化了现有全自动钵苗移栽机的电动或气动送秧和投苗装置，降低了成本。移栽器的性能试验表明，所研制的移栽器性能良好，适应国内市场需要。     

松软土壤上步行轮式气垫车功率优化的研究

通过对步行轮式气垫车在松软土壤上运行状态的分析，首次提出了该种车辆最佳飞高的定义，得到了随土壤条件变化时功率消耗模型，并求出了功率消耗的最优点。为步行轮式气垫车在松软土壤上的功率自适应控制打下一定基础。     

Assessing air-drying and rewetting pre-treatment effect on some soil enzyme activities under Mediterranean conditions

Soil enzyme activities are useful indicators of soil quality as they are very sensitive to disturbance. Sample storage or pre-treatments could affect the results in these assays, which are normally determined in fresh samples, kept cold or frozen. The objectives of this study were to (i) evaluate the effect of air-drying or air-drying and rewetting on β-glucosidase, acid phosphatase and urease activities in soils from different locations, degradation status and sampling seasons, and (ii) assess if air-drying or air-drying and rewetting is an accurate sample storage and pre-treatment procedure for enzyme activities in soil quality evaluations under semiarid Mediterranean conditions. Our results showed that urease, phosphatase and β-glucosidase activities were hardly affected by air-drying of degraded and non-degraded soils from the two locations studied in all seasons. Short incubations (4, 8 and 12 d at 23 °C) of rewetted air-dried soil at 55% of water-holding capacity showed different patterns depending on the enzyme studied. Urease and β-glucosidase activities were relatively stable during incubation, with several significant (P<0.05) shifts up and down in some soils and samplings. However, acid phosphatase showed an increase in activity with incubation, of between 5% and 50% relative to air-dried samples. These increases followed no pattern and were unrelated to soil characteristics or sampling date. Hence, urease, phosphatase and β-glucosidase activities determined in air-dried soil samples seem to be representative of those obtained under field-moist conditions. In contrast, short incubations of rewetted soil samples can produce fluctuations in these enzyme activities, mainly of acid phosphatase, and estimations in these conditions are not so representative of field-moist soil values.