深水抗风浪网箱监测系统研制方案的探讨

探讨一种声学监测方案,用高频、窄脉冲和分裂波束技术,实时监测养殖鱼的进食、生长情况,随时评估网箱内总量的增长情况,并且从水产行业的成本可承受性的实际出发,将成本控制在用户可接受的水平上。     

可发酵碳水化合物减少猪场臭气的机理和应用

可发酵碳水化合物,添加在猪日粮中到达后肠作为微生物发酵的底物,通过改变猪肠道和粪便中的微生物及其发酵过程,改变粪尿的理化特性,来减少氨的挥发以及臭气的产生.本文对臭气和除臭方法进行了简单的介绍,并综述了通过在猪日粮中添加可发酵碳水化合物来控制猪场臭气的机理和应用效果.     

Performance of a closed recirculating system with foam separation, nitrification and denitrification units for intensive culture of eel: towards zero emission

The development of a closed recirculating aquaculture system that does not discharge effluents would reduce a large amount of pollutant load on aquatic bodies. In this study, eel were reared in a closed recirculating system, which consisted of a rearing tank, a foam separation unit, a nitrification unit and a denitrification unit. The foam separation unit has an inhalation-type aerator and supplies air bubbles to the rearing water. The growth of eel, which were fed a commercial diet, was satisfactory, with gross weight increases of up three times in 3 months. The survival rate under the congested experimental conditions was 91%. The foam separation unit maintained oxygen saturation in the rearing water at about 80%. Furthermore, fine colloidal substances were absorbed on the stable foam formed from eel mucus and were removed from the rearing water by foam separation. Ammonia oxidation and the removal of suspended solids were accomplished rapidly and simultaneously in the nitrification unit. The ammonia concentration and turbidity were kept at less than 1.2 mg of N per litre and 2.5 units, respectively. When the denitrification process was operated, nitrate that accumulated in the rearing water (151 mg of N per litre) was reduced to 40 mg of N per litre. The sludge was easily recovered from the nitrification and denitrification tanks, and the components were found suitable as compost. Based on these results, the intensive aquaculture of freshwater fish such as eel can be achieved using a closed recirculating system without emission.     

果树冠层参数实时检测系统

为了降低农药喷施环境污染和提高水果品质,实现果园果树仿形精确喷雾,建立了一套果树冠层参数的实时检测系统.该系统主要由作物识别系统、车辆姿态系统、主控单元和数据记录单元组成,采用CAN总线进行数据通信.对5棵临近的绿篱树进行了初步的靶标距离检测试验,试验重复3次.采用4个超声波传感器分时检测,拖拉机前进速度为0.3m/s,系统采样速率为5次/s.试验表明,系统能可靠地按一定的采样速率,实时检测和记录系统载体车辆位置、姿态(地面平整度)和果树靶标的距离等数据,为精确仿形喷雾提供了一个较好的喷雾控制平台.     

影响简易瞬态工况法(VMAS)测量精度因素分析

控制在用车的排放已经成为共识,国家标准规定了几种在用汽车排放的测量方法,简易瞬态工况法(VMAS)是其中之一.给出了简易瞬态工况法(VMAS)检测设备系统的组成和测量原理,从设备自身、被检车辆、人为因素、燃油品质和周围环境等几个方面分析了影响简易瞬态工况法(VMAS)测量精度的因素.     

大力发展造纸业清洁生产促进节能减排

分析了我国造纸业现状及面临的环境压力,指出了我国清洁生产现状及发展趋势。针对造纸业"消耗高、污染大、效率低"问题,结合实际造纸行业案例提出了相应的清洁生产工艺和方案,为促进节能减排实现造纸业经济发展与环境保护的统一提供参考,对于大力发展造纸业清洁生产促进节能减排,提出了相应的建议。     

基于声发射技术的木材害虫信号特征检测

针对木材害虫声发射（AE）信号检测问题,研究杨树木段中麻点豹天牛幼虫AE信号波形特征及其信号的能量,为钻蛀害虫声音的监测提出一种新的方法。取一段具有麻点豹天牛幼虫的杨树木段,通过采样频率为500 kHz的2通道木材蠕变声发射信号采集系统采集原始AE信号。对采集到的原始信号滤波后进行小波分解,通过对各层高频信号的分析获取AE信号的频域特征,并对其进行重构与信号解析。结果表明,麻点豹天牛幼虫AE信号的主频主要集中在30 kHz附近,其信号的能量在16:00最高,反映了该幼虫在15:00-16:00较活跃。     

Nitrous oxide emission measurement with acetylene inhibition method in paddy fields under flood conditions

Nitrous oxide (N₂O) emission from flooded rice paddy fields was continuously measured by the closed chamber method at an experimental plot in Thailand for a whole cultivation period. To characterize the N₂O emission with regard to the denitrification N loss, the C₂H₂ inhibition method was applied. Flood water on the soil greatly suppressed the N₂O emission. The N₂O emission was mitigated considerably by even a thin film of the flood water. The overall average N₂O emissions under flood conditions for one crop season (83 days) at the control site and the C₂H₂ treated site were 10.3 and 11.8 μg N m⁻² h⁻¹, respectively. The N₂O emission from the C₂H₂ treated site was consistently higher than that from the control site and the N₂O emission from both sites followed the same diurnal and seasonal variation pattern, indicating the effect of denitrification inhibition by the supplied C₂H₂. The N₂O emission enhanced along with temperature increase when NO₃–N concentration in the soil water was above 0.4 mg N l⁻¹ and soil temperature was above 24°C, suggesting specific temperature influence over the emission. The increase in NO₃–N concentration and temperature in the soil affected only the N₂O emission while the difference in the emission at the C₂H₂ treated site and the control site was not so much affected. It was suggested that most of the actively produced N₂O under higher NO₃–N concentration and temperature would likely to quickly emit to the atmosphere rather than to undergo further reduction to N₂.     

中国城市化发展、能源消费与碳排放的实证研究

选取了1995年至2007年我国29个省市面板数据,建立以城市化水平为被解释变量,能源消费和碳排放作为解释变量的模型,通过协方差分析检验和Haus man检验的分析结果,确定研究模型的形式为固定影响变截距模型,最后,通过对拟合模型的结果分析,实证结果表明：高能耗、高排放、粗放式经济发展方式不利于城市化水平的提高;同时,各省市的城市化发展水平也存在差异.因此,各省市应在城市化工业化进程中推进产业结构和能源消费结构调整使其朝着更有利于节能环保的方向演进,节能减排政策的调整重点应该放在能源强度和能源消费碳强度上.     

海水网箱养殖中的排污收费问题研究

网箱养殖是近年来海水养殖业发展的主流趋势,在其带来巨大经济效益的同时,也对周边生态环境造成巨大的威胁和破坏。文章通过探析其经济学原因,提出通过排污收费的手段来解决高密度海水网箱养殖带来的环境问题,并建立确定排污税率标准的模型,以部分黄渤海地区的数据进行实证计算,得出各地区的排污税率以供参考。