PVA固定化污泥反应器启动特性的研究

比较了ＰＶＡ固定化污泥反应器和游离污泥反应器在启动过程中的特性差异。结果表明，ＰＶＡ固定化污泥反应器能在高浓度ＣＯＤ下稳定启动，能抗高容积有机负荷和水质不稳定的冲击，ＣＯＤ绝对去除量高２～３倍，出水ＳＳ和Ｏ．Ｄ值明显较低，ＶＦＡ浓度较低而总碱度（ＴＡ）较高，污泥产酸活性和产甲烷活性也较高。游离污泥反应器的性能相对较差，这种差异的微生物学原因在于污泥经ＰＶＡ固定后建立了良好的产酸化和产甲烷化的互营体系，而游离污泥反应器形成这种互营体系则需要较长的时间。     

我国磷酸一铵、磷酸二铵产品质量状况浅析

通过总结1999~2006年磷酸一铵、磷酸二铵产品质量国家监督抽查结果,分析了我国磷酸一铵、磷酸二铵产品质量状况,指出我国该类产品质量较好,但限于磷矿资源不足,矿源复杂,质量控制越来越困难。同时,该类产品农田使用量降低,多数用做复混肥料原料,应加大施肥技术推广。     

谈GPSS仿真试验中初始状态的设置方法

在计算机仿真试验中初始状态的设置非常重要 ,本文结合实例 ,提出了设置初始状态的几种方法 ,并探讨了各自的适用条件     

关于联合办学的几点思考

开展多种形式的联合办学是高等教育适应经济、科技和社会发展的需要。突出农专特色，积极开展联合办学，培养不同层次、不同类型的实用人才是农专教育教学改革的重点。发展联合办学，必须坚持解放思想、更新观念、注重质量、讲究实效。     

The use of getting up and lying down movements in the evaluation of cattle environments

The aim of this review is to find out if getting up and lying down movements can be used as one of several parameters when evaluating different cattle environments. Getting up and lying down movements are performed according to innate movement patterns. An unsuitable environment can cause these movements to become incomplete or abnormal and so lead to injuries. Physiological measurements at lying down show a greater change in tethered cattle than in cattle kept on deep litter. In short stalls the use of certain types of tethers and the height of the manger edge affect the normal getting up and lying down movements. Unsuitably designed cubicles in loose housing systems can lead to changed movement patterns. Calves and fattening bulls have fewer lying down and getting up movements and longer lying intervals on slatted floors than on deep litter. Calves kept in small individual crates carry out a large percentage of their lying down and getting up procedures abnormally. In this review it is shown that it is possible to make improvements in the environment of cattle by using results from studies of these behaviour patterns. The conclusion is that getting up and lying down movements can be used as one of several parameters when evaluating different cattle environments.     

A short note on the horizontal and vertical movements of a whale shark, Rhincodon typus, tracked by satellite telemetry in the South China Sea

Whale sharks, a global migratory species, are often reported entangled in fishing nets in coastal areas of China. The effectiveness of conservation measures has been constrained by very limited knowledge on their movements and preferred habitats in the coastal areas of China. For the first time, we tracked the movements of 2 whale sharks by satellite telemetry in Mainland China. The tracking results of 1 whale shark revealed that it travelled in the South China Sea in a south-eastern direction, parallel to the eastern coast of Vietnam. Total distance travelled was 1018 km, in approximately 74 days, with a mean speed of 14 km per day. It appeared to head towards the cool upwelling zones in southern Vietnam at the time of the tag's detachment. In our study, it was observed that this whale shark was a surface dweller and spent approximately 45% of its time above 10 m water depth and 90% of its time above 50 m depth. It also tended to stay in water temperatures between 27 and 30 °C, and was rarely recorded in water below 20 °C. This preliminary study indicates the importance of shallow waters as the foraging habitat for whale sharks, and has implications for their management and conservation.     

基于变异函数的油松毛虫虫情监测点布点方法研究

通过变异函数工具研究了喀左县油松毛虫Dendrolimus tabulaeformis发生的空间异质特征。变异分析表明:喀左县油松毛虫发生变异函数的理论模型符合球状模型,空间变异受结构因子(C)的影响占98%,受随机因子(C0)的影响占2%,确定性因素对空间异质性的影响远大于随机因素,其变异具有强烈的空间相关性。油松毛虫发生程度最大相关距离为7.98 km。每40.7 km2设1个监测样点,"品"字型均匀布设,基本能满足油松毛虫发生分布估计要求。     

论森林资源变档工作在林业建设中的作用

文章根据辽宁省5年来森林资源变档工作实践,论述森林资源变档工作,管理模式、内容、在林业建设中的作用、及存在的问题、提出相应对筞。森林资源变档以小班为单位,通过科学技术手段,实现了每年更新一次森林资源数据,实现了从静态管理到动态管理转变。为各级政府、林业主管部门、及森林经营单位制定林业方针政策,编制林业规划设计、指导林业生产提供科学基础数据,为调整林业政策、提高林业管理水平,提供最新的科学依据。     

砂壤质褐土水力特性与物理性质的空间尺度效应——消除趋势波动分析法

土壤水力特性与物理性质的空间异质性及其之间的关系在不同尺度上会有不同表现。采用消除趋势波动分析法对土壤水力特性(田间持水量、萎蔫系数和饱和导水率)和物理性质(机械组成、容重和有机碳含量)进行尺度分析。结果表明,只有在一定尺度范围内才能进行土壤水力特性空间变异分析和尺度转换(外推)。过小的尺度范围内不能摆脱空间相关的束缚,尺度太大时不能抓住主要控制因子,因此无法进行尺度外推。所研究砂壤质褐土田间持水量、饱和导水率、容重和有机碳含量可外推尺度范围较大,分别为55~155、50~125、50~125和50~135 m;砂粒、粉粒和黏粒含量的可外推尺度范围较小,为50~85 m,因此在进行空间尺度转换前应先确定其尺度外推范围。