辽西地区垄作和平作保护性耕作方式比较研究

比较了平作和垄作下不同保护性耕作方式对土壤水分、温度和作物生长发育和产量的影响。结果表明,几种耕作方式中平作的平均产量都要高于垄作,其增产率在11.38%￣15.20%之间。在相同的垄作或平作方式下,不同的保护性耕作方式的增产幅度不同,其中秸秆还田增产幅度最大。平作方式的出苗率、叶面积指数、根干重和干物重都高于垄作,但不同的保护性耕作方式其各项指标变化有所不同。平作下保护性耕作方式的土壤含水量高于垄作;垄作方式有一定的增温效应,尤其在苗期的土壤表层。     

植物多叶片图像目标识别和叶面积测量方法

分析了图像处理方法测量叶面积中采用CCD照相机和扫描仪2种采集设备各自的优、缺点.针对目前各种叶面积测量方法均为逐片测量的局限性,以MATLAB数学分析软件为平台开发了对多叶片扫描图像中各叶片进行目标识别和面积计算的算法.试验结果表明,该算法在叶片间不重叠的条件下识别准确率达到100%,测量得到的叶面积与采用称重法得到的叶面积间的相对误差为2.43%,决定系数(R2)为0.999 6.试验证明,该算法可以实现对多叶片扫描图像中各叶片的准确识别和叶面积测量.     

宁德市沿海滩涂资源开发与利用

沿海滩涂不仅是一种重要的后备土地资源,而且蕴藏着丰富的水生物、港口、再生能源、矿产、旅游等资源,具有巨大的开发潜力。宁德市位于福建省东北部,地理位置优越,滩涂资源丰富,随着基础设施的不断完善和改革开放的深入,尤其是高速公路同三线福建省境内的全线贯通,为宁德滩涂养殖业带来了新的机遇和挑战。宁德沿海滩涂资源的开发利用经历了新中国成立初期的粗放开发阶段,20世纪50年代中期到80年代的传统利用阶段和90年代以来的综合开发利用阶段,同时滩涂资源开发利用过程中存在着缺乏统一的开发利用总体规划、滩涂产业结构层次低、科技投入不足产值规模小、生态环境日趋恶化、浅海滩涂网箱养殖环境日益突出等问题。为此笔者认为新时期宁德市沿海滩涂资源开发利用应当坚持调整产业结构,培育滩涂主导产业,合理布局科学养殖,实施科技兴滩战略,优化滩涂湿地环境、建设和维护良好的生态环境,提高区域滩涂开发效益。     

连续平压机入口角度动态控制方法

基于钢材弯曲变形的特点,提出一种矩形截面的入口上热压板弯曲变形来调节入口角度的方法。在分析上热压板弯曲变形原理并推导曲率半径与拉弧高度几何关系的基础上,仿真计算上热压板弯曲强度,构建基于现场总线的分布式系统和人机交互控制系统,设计油缸位移梯度渐进算法并在国产连续平压机上实现控制。研究结果表明:入口上热压板弯曲变形满足弯曲强度要求,入口角度调节方法及控制算法能够实现油缸位移梯度变化的渐进性和入口角度调节的动态性;当入口曲率半径R为100 000 mm时,入口上热压板拉弧高度理论值与实际值最大偏差为0.4 mm,横向实际值最大偏差为0.6 mm,达到控制精度要求。     

Modelling seawater intrusion in the Burdekin Delta Irrigation Area,North Queensland,Australia

The Burdekin Delta is a major irrigation area situated in the dry tropics of North Queensland. It is unique in that (i) it overlies shallow groundwater systems that serve as a major water supply for the irrigation of sugarcane, and (ii) it is adjacent to the world heritage listed Great Barrier Reef. Water management practices include large recharge pits and surface spreading of water to assist with replenishment of the groundwater. This has been useful in maintaining groundwater levels to help control seawater intrusion. This technique, however, can be costly and ineffective in unconfined aquifer systems, which are subjected to large amounts of groundwater pumping for irrigation. There are more than 1800 production bores currently used for irrigation in the Burdekin Delta and the large volumes of water extracted have at times lowered the regional water tables and made it difficult to control seawater intrusion.     

柱塞式平模生物质成型机设计与试验

针对传统生物质平模成型机能耗高、磨损严重的问题,该文提出了一种柱塞式平模生物质致密成型方法,并设计了成型机样机。该样机通过斜盘与弹簧配合,驱动柱塞往复运动,柱塞在运动过程中仅对模具内的原料进行挤压。成型模具部分采用组合式设计,主要由平模与成型套筒组成,可在成型套筒外部加热,同时可更换长径比不同的成型套筒以适应不同生物质原料。该文以不同颗粒度玉米秸秆和刺槐为原料,在原料含水率为15%,斜盘转速为50 r/min,原料温度为室温的条件下进行了试验,结果表明柱塞式平模生物质成型方法可行,颗粒成型率均高于98%,成型密度大于1.1 g/cm3,机械耐久性高于97%。该文提出的成型方法为生物质致密成型技术提供参考。     

浅圆仓"三温"变化特性初探

本文探讨了在春、夏气温上气季节华南地区浅圆仓储粮在不同半径及不同深度的粮温随气温及仓温的变化规律。     

广东省围填海对近海生态环境影响研究进展

基于有关广东省围填海对近海生态环境影响的文献资料,综述了广东省围填海与海岸线变化的关系,圉填海对滩涂和红树林等海岸湿地生态系统的影响,以及近海海洋生物对广东围填海的响应.最后指出了广东省围填海生态影响研究中存在的薄弱环节,并对其未来发展方向进行了展望.     

Histopathology and a real-time PCR assay for detection of Bonamia ostreae in Ostrea edulis cultured in western Canada

Bonamia ostreae is an intracellular haplosporidian parasite in European flat oysters Ostrea edulis that occurs on both coasts of the United States and causes significant mortality in Europe. Canada was considered free of B. ostreae until 2004, when it was first detected in O. edulis obtained for laboratory study from a western Canadian oyster farm. Bonamia ostreae was confirmed in O. edulis at the index farm in November 2004 using histopathology, conventional polymerase chain reaction (PCR) assays, restriction fragment length polymorphism (RFLP) analysis, and sequencing of the PCR product. Archived samples of European flat oysters obtained from the index farm between 1999 and 2004 (n = 343) were re-examined and all samples collected before 2003 (n = 306) were confirmed negative for B. ostreae by histopathology (n = 306) and PCR (n = 62). In archived samples from 2003, B. ostreae was detected in 3 of 37 O. edulis by histopathology (n = 2) and/or PCR (n = 2). Also, records indicate that B. ostreae was not detected in O. edulis (n = 348) from five other locations in western Canada between 1986 and 2000. To better understand the distribution and prevalence of B. ostreae in western Canada, 607 oysters from the index farm and 2 additional farms were sampled in the summer of 2005. All 3 farms had been stocked with O. edulis spat from the State of Washington, USA, where B. ostreae is endemic. Samples were analyzed by histopathology and a new real-time PCR that amplifies a 68-bp target DNA fragment. B. ostreae was detected in all three locations, with prevalence ranging from 0.5 to 11.1%. Diagnostic sensitivity of the real-time PCR method was consistently greater than histopathology. Also, preliminary evidence supports the conclusion that real-time PCR on paraffin sections is more sensitive than histopathology; B. ostreae DNA was confirmed in 4 oysters by real-time PCR on paraffin-embedded tissues (and independently confirmed on unfixed tissues) that was not detected by histopathology. As a result of these findings, O. edulis spat are no longer allowed to be imported from endemic areas into Canada.     

无土栽培设施在农村平房顶上的应用模式研究

研究将温室建筑技术、房屋建筑技术和无土栽培技术相结合,设计出一种用于平房顶上进行无土化快速栽培芽苗菜、药用植物及花卉等的装置,装置采用小型家用太阳能电池组件和节能灯的照明系统,可节省土地、节能环保,具有进行芽苗菜、药用植物及花卉等的快速立体种植的功能。研究从原材料使用、设计思路、工艺工序、利用价值及应用推广前景等方面进行阐述,构建一种双层立体结构设计的拱形大棚,解决农村及城市周边平顶房屋闲置的问题。该装置的应用推广,充分利用农村及周边闲置平房顶资源和太阳能,既缓解土地资源利用的压力,又践行节约集约用地的理念,达到低碳、节能、环保的目的。该装置的使用还实现蔬菜等的全年种植,缩短其生长周期,提高劳动生产率,显著提高农村及城市周边大量闲置平顶房屋的应用价值和经济效益。