基于TLM2．0的硬件虚拟平台设计

利用OVP（Open Virtual Platform）提供的模型创建基于TLM2．0的硬件虚拟平台,可以为嵌入式软件提供一个快速有效的开发环境,实现软件和硬件的协同设计。提早开发出的软件也可以对系统虚拟平台进行功能验证,分析系统性能,确定系统的最优架构。     

嵌入式软键盘UI一致性与功能差异性的研究

为了解决嵌入式WinCE系统所带软键盘按钮小和嵌入式设备触模操作便捷性要求之间矛盾,本文提出设计软键盘代替WinCE系统所带软键盘。为了解决嵌入式系统中多个数据输入的软键盘界面与嵌入式系统资源有限的矛盾,在设计中,提出了一种将软键盘界面与增加数据功能、删除数据功能、显示数据功能、数据合法性检查功能等键盘处理逻辑分离的技术,不同功能模块调用统一软键盘界面,实现了软键盘UI一致性和功能差异性,从而节省了系统资源;此外,为了减少软键盘按钮数,在小触模屏条件下触模按钮做得更大,提出了系统附加数据单位字符技术,这种技术也提高了用户数据输入速度。综合运用这些技术,完成了基于WinCE平台软键盘开发研制,实际应用表明提高了操作便捷性。     

用仪器中子活化分析法检验环境土壤标样的均匀度

近年来,国际上标准参考物质的种类与数量急剧增加,一些重要的领域,象地球化学、环境科学、生物学等都有了相应的SRM。国内研制SRM的工作也十分活跃。 标准样品必须均匀,故在分析定值和样品发行前,需要先作均匀性检验。由于均匀性是一个相对的概念,它与各个元素在SRM中的分布紧密相关。取样量直接影响均匀性的好坏。因此,当给出SRM中某元素的均匀性数值时,必须注明相应的取样量。由于仪器中子活化分析法(INAA)具有灵敏度高、不破坏试样、且可同时测定多种元素等特点,因此可在较小的取样量情况下,实现对SRM中多种痕量元素的均匀性检验。     

LF软吹时间对硅脱氧弹簧钢氧化物夹杂控制影响

 对于一些采用硅锰脱氧冶炼工艺的特殊钢,为保证钢水洁净度,常会选择较长时间的LF软吹处理,导致过程能耗增加。通过工业试验,借助FEI Explorer 4自动扫描电镜检测,研究不同LF精炼软吹时间对硅脱氧弹簧钢55SiCr铸坯氧化物夹杂成分、数量的影响;并采用夹杂物极值统计法,对比评价不同LF精炼软吹时间对应成品盘条横截面最大夹杂物尺寸控制情况。结果表明,在LF软吹10 min与软吹40 min 两种工艺条件下,铸坯中尺寸大于5 μm的氧化物夹杂成分接近,均在CaO-SiO₂-Al₂O₃相图中假硅灰石、钙长石和钙铝黄长石共晶低熔点区,其中软吹10 min工艺铸坯氧化物夹杂组成落入低熔点区的数量所占比例更大。LF软吹10 min与软吹40 min铸坯中尺寸大于5 μm的氧化物夹杂数量密度分别为11.70个/100 mm2和14.59个/100 mm2,尺寸大于15 μm 的氧化物夹杂数量密度分别为0.53个/100 mm2和1.65个/100 mm2,LF软吹10 min工艺铸坯大尺寸氧化物夹杂数量密度略低于LF软吹40 min工艺。当预测面积为30 000 mm2时,两种LF软吹时间对应成品盘条横截面最大夹杂物尺寸分别为27.1 μm和28.1 μm,盘条最大夹杂物尺寸控制无显著差别。结合硅锰脱氧钢中大尺寸低熔点CaO-SiO₂-Al₂O₃系夹杂物主要源自钢包渣乳化卷入,具有与钢水和氩气泡界面接触角很小、难以通过吹氩上浮去除的特点,建议硅锰脱氧钢LF软吹过程按短时间快节奏进行控制。     

Simulation of nitrogen dynamics and biomass production in winter wheat using the Danish simulation model DAISY

A dynamic simulation model for the soil plant system is described. The model includes a number of main modules, viz., a hydrological model including a submodel for soil water dynamics, a soil temperature model, a soil nitrogen model including a submodel for soil organic matter dynamics, and a crop model including a submodel for nitrogen uptake. The soil part of the model has a one-dimensional vertical structure. The soil profile is divided into layers on the basis of physical and chemical soil characteristics. The simulation model was used to simulate soil nitrogen dynamics and biomass production in winter wheat grown at two locations at various levels of nitrogen fertilization. The simulated results were compared to experimental data including concentration of inorganic nitrogen in soil, crop yield, and nitrogen accumulated in the aboveground part of the crop. Based on this validation it is concluded that the overall performance of the model is satisfactory although some minor adjustments of the model may prove to be necessary.     

磁性材料产业现状与展望

介绍磁性材料的主要品种，如永磁体、软磁体和磁记录介质材料的行业现状及技术进步。     

Effect of nitrogen,phosphorus and soil and crop residues management practices on maize (Zea mays L.) yield in ultisol of eastern Cameroon

The shortening of fallow period in several areas in tropical Africa has reduced soil fertility and exposed soils to erosion and run-off. Fertilizer application and crop conservation practices are needeed to sustain high crop yield and to conserve the natural resource base for upland crop production in the continent. Field trials were carried out to evaluate the effect of fertilizer application and soil and crop residues management practices on yield of maize (Zea mays L.) planted on a Plinthudult soil at Bertoua, Eastern Cameroon. Maize yields increased significantly with nitrogen and phosphorus fertilizer application. Under the rainfall pattern prevailing in the area, the amount of nitrogen required for maximum yield was higher in the second season. On the other hand, the amount of phosphorus required for maximum yield appeared to decrease with time. The burning of crop residues and weeds prior to planting together with no-till practive gave higher yield of maize than other soil and crop residues management practices.     

Lowland rice response to potassium fertilization and its effect on N and P uptake

Not much is known about the response of lowland rice to K fertilization under Brazilian conditions. A field experiment was conducted during four consecutive years to determine the response of three lowland rice (Oryza sativa L.) cultivars to K fertilization on a Low Humic Gley soil. In the first two years, K was broadcast at rates of 0, 42, 84, 126, and 168 kg K ha^–1. In the last two years K rates were reduced to 0, 25, 50, 75, and 100 kg K ha^–1 and applied in a band. Potassium significantly (P < 0.01) increased grain yields but the response varied from cultivar to cultivar and year to year. Yield responses to K fertilization were superimposed on a general trend of increasing grain yields across the four growing seasons. Mean grain yields increased 14.3% with broadcast application of K in the first two years and 10.4% with banded application of K in the last two years when compared to the control treatments. Extractable soil K increased with K application rate and decreased with soil depth. Potassium was rapidly removed from the soil and yearly broadcast or banded application of K can be expected to result in a significant increase in grain yield of lowland rice in these soils.     

基于TS201的信号处理软件设计

基于TS201处理器的软件优化设计,对于提高运算效率和运行稳定性是非常关键的。结合具体项目和实际工作经验,对如何正确利用TS201处理器的各种资源进行了分析,并提出了优化设计方法。按此方法设计的信号处理软件已成功应用到了某探测系统中,实现了系统提出的各种功能,并满足实时性要求,软件运行稳定,验证了所提方法的正确性。     

基于FDR原理的自动灌溉系统设计

利用土壤的介电特性测量土壤含水量是一种快速、简便、可靠的方法。根据频域反射(FDR)法测量原理,电磁波在土壤中的传播频率可用来测试土壤的介电常数,从而得到土壤容积含水率,设计出了一种基于FDR原理的自动灌溉系统,介绍了FDR测量原理,阐述了自动灌溉系统的软硬件构成,土壤水分传感器测得的土壤水分含量信息,经信号处理,输出为0~5V电压信号,经A/D转换送至AT89S52单片机进行判断处理,根据输出数值的大小控制电磁阀的通断时间,从而实现自动灌溉和节水灌溉的目的。试验表明:该系统工作稳定,控制准确,反应灵敏,满足自动灌溉要求。