Economic performance and comparative riskiness of different management practices for control of botrytis fruit rot in florida strawberry

Florida strawberry farmers usually rely on weekly calendar fungicide applications to prevent yield loss from Botrytis fruit rot (BFR). The Strawberry Advisory System (SAS), which helps optimize the timing of fungicide applications, is an additional tool in the farmers' arsenal of disease control options. This study uses data from two-year production trials in Florida combined with historical strawberry prices to measure the economic performance of the Calendar and SAS-based BFR management practices under output price risk and producers' risk preferences. We use Monte Carlo simulation to model the effect of the variability in weekly output prices on farm returns. Results reveal that the traditional calendar-based system is not the least risky BFR management option as growers expected to be. SAS-based options such as SAS-Switch and SAS-Luna would be preferred by both risk-neutral and risk-averse producers and are recommended under high disease pressure conditions.     

流固耦合方法对气携旋流分离的数值模拟

指出了气携式液液旋流器是港区小型化、船载化洗舱、压仓含油废水预处理的关键设备.采用流固耦合数值模拟方法再现压缩机进气、油水旋流与设备本体的整体气浮—旋流—分离耦合计算模型 ,对其核心部件微孔旋流套管的构型、孔径、内外压差及腔内流场分布进行了三维数值模拟 ,得到了微孔旋流腔内汽、水、油三相的流场分布 ,合理确定了注气腔气—水平衡分压、溢流比和微孔孔径 ,并模拟了压缩机、潜水泵正常工况下进气、进水、出水、油污溢流的流量、流速波动范围 ,为该设备的一体化构型设计和加工选材提供了参考数据.     

基于联合仿真的林业采育作业模拟系统研究

为解决大型林业装备操作训练复杂的问题,优化驾驶与作业,提高森林资源利用率,本文提出基于分布式系统,对采育作业环境进行视景模拟的虚拟现实作业操作模拟器。系统利用虚拟现实软件Unity3D系统,能够模拟车辆行驶与工作的动力学模型,实时运动仿真包括底盘系统与地面的交互作用,机械臂作业运动以及伐木头作业操作运动,使操作人员能够更快地适应熟悉驾驶和采育作业,减少安全隐患和装备损耗,提高装备作业安全性及效率。     

Research and Design of Simulative System of Elevators Based on Java

设计了控制电梯运行的调度算法；其次，采用面向对象语言编写程序模拟电梯运行，其中使用双缓冲技术来解决电梯图片在刷新过程中出现的闪烁现象；最后，测试该系统的正确性和合理性。     

库车坳陷克深地区现今地应力场及储层裂缝数值模拟

克深三维区目前处于勘探开发的前期,需要明确地应力场及地下储层裂缝的分布规律,指导开发工作,但该区存在地层埋深大、取心困难、成像测井资料缺乏等实际情况,应力场研究及裂缝预测难度大。利用有限元分析方法,以井点现今地应力值为约束进行了克深三维区现今地应力场的数值模拟,同时建立了应力应变与裂缝参数的定量关系模型,利用古今应力场结合法对克深三维区的裂缝参数进行了预测,模拟结果显示构造高部位和断层带是低应力值区及裂缝的有利发育区。裂缝的数值模拟结果与测井解释结果对比表明,预测结果与实钻吻合度较高,裂缝预测效果较好。     

双源热压机传热分析及输送管道结构设计

利用ANSYS有限元软件对单源载热体(导热油加热,水冷却)和双源载热体(热油和蒸汽同时加热,冷油和水同时冷却)的热压板孔道结构分别进行传热仿真分析,得到相应的温度分布云图及热压板温度随时间的变化曲线.传热仿真分析结果显示,在同样条件下用双源载热体把热压板加热到140℃所用的时间比单源载热体少200 s,双源载热体加热热压板板面最大温差1.2℃;双源载热体冷却所用的时间比单源载热体少330 s,板面最大温差2.6℃.表明采用双源载热体产品可达到优等品的生产要求.同时设计了与双源载热体相适应的载热体输送管道结构.     

基于三维结构的胡杨茎生长模型的研究与可视化

植物生长模拟研究,是利用计算机仿真技术来模拟现实中植物的生长状态。论文以胡杨生长数据为基础,通过实验分析,推出了胡杨树高与胸径之间的关系,提出一种基于三维结构的胡杨茎生长模型,并运用3DMax技术实现胡杨茎生长模拟的可视化,同时给出了从不同角度模拟胡杨茎生长的状态图,从而全面反映了胡杨茎的生长模拟。     

基于AquaCrop模型的夏玉米生长模拟及灌溉制度优化

为评价AquaCrop模型在关中地区的适用性并寻求最佳的灌溉制度，对夏玉米在不同灌溉与施氮水平下的生长进行模拟和验证，并利用校验后的模型研究了3种不同降雨年型以及11种灌溉模式下夏玉米产量和水分利用效率的变化特征。结果表明：AquaCrop模型可以较好地模拟关中地区不同灌溉与施氮水平下夏玉米产量和生物量，模型模拟的产量与实测值之间的决定系数（R²）、均方根误差（RMSE）、标准均方根误差（NRMSE）、符合度指数（d）和纳什效率系数（E_NS）分别为0.919、0.249 t·hm^-2、4.112、0.977和0.915；对于地上部生物量，模拟值与实测值的R²、RMSE、NRMSE、d和E_NS分别为0.860、0.977 t·hm^-2、6.407、0.933和0.694。利用校验后的模型分析了试验区内3种不同降水年型条件下11种灌溉模式的夏玉米产量和水分利用效率的变化特征，依据模拟结果及夏玉米生理需水规律，同时为了实现高产和高水分利用效率，得出不同年型的优化灌溉制度为：若能保证出苗整齐，湿润年可不灌水，此时也能获得较高产量和水分利用效率；平水年推荐在拔节期灌水60 mm，能节约50%水资源，亦能保证稳产；干旱年推荐在拔节期和抽雄期各灌水60 mm，可获得高产和高水分利用效率。     

Hybrid breeding for biomass yield in winter triticale: II. Combining ability and hybrid prediction

Accurate hybrid prediction and knowledge about the relative contribution of general (GCA) and specific combining ability (SCA) are of utmost importance for efficient hybrid breeding. We therefore evaluated 91 triticale single-cross hybrids in field trials at seven environments for plant height, heading time, fresh biomass, dry matter content and dry biomass. Fresh and dry biomass showed the highest proportion (23%) of variance due to SCA. Prediction accuracies based on GCA were slightly higher than based on mid-parent values. Utilizing parental kinship information yielded the highest prediction accuracies when both parental lines have been tested in other hybrid combinations, but still moderate-to-low prediction accuracies for two untested parents. Thus, hybrid prediction for biomass traits in triticale is currently promising based on mid-parent values as emphasized by our simulation study, but can be expected to shift to GCA-based prediction with an increasing importance of GCA due to selection in hybrid breeding. Moreover, the performance of potential hybrids between newly developed lines can be predicted with moderate accuracy using genomic relationship information.