地下工程导线测量中加测陀螺方位角的最佳位置研究

针对地下工程导线测量中,采用测角量边的单一导线控制测量而导致控制精度较低的问题,分析了直伸型导线测量中加测陀螺方位角的数量及其增益,并探讨了直伸型导线和非直伸型典型导线,如L,Z,U型导线加测陀螺方位角的最佳位置。     

减阻剂在我国输油管道上的应用试验

减阻剂是一种高分子聚合物的化学制品，能减少液体在管道内流动的摩阻。国外在７工就开始将减剂应用在原油管道上，我国于８０年代中期才开始在原油管道上进行减阻剂的试验。对减阻剂的减阻机理和特性作了分析，并着重介绍了利用国外减阻剂在国内几要输油管道上做应用试验的情况，大量的试验证明了减阻剂的减效果，同时指出，在我国的输油管道上的应用减阻剂有着广阔的前景，对输油管道的增输，节能降耗，提高经济效益和社会效益都能     

群钻钻削力试验及其分析

通过试验得出了群钻切削刃段钻削力的分布规律和切削用量对钻削的影响。     

AN APPRONTMATE CALCULATING METHOD FOR WALL PLATES OF MAN'' S DRY GAS HOLDERS

The basic equations of wall plates of MAN' S dry gas holders are derived in this paper. According to the law of cylindrical bending given by the finite element results .we derive some approximate formula calculating the deflection and stresses of the wall plates from the basic equations. Compared with the known approximate calculating method.the method car. obviously increase the percision.     

一种变形拉丁方设计

为了在两个方向上控制田间试验的地力差异,而又不过分限制处理数m的取值,本文提出了一种变形拉丁方设计的试验方法。该种设计是在随机区组设计的基础上,将n个区组做为行区组看待。再将这n个行区组的m个小区分成n个段作为列区组来布置试验,并使所有处理在每个行区组和每个列区组中都只出现一次。在方差分析中,将行区组和列区组     

Estimation of associative nitrogen fixation in relation to water regime and plant nutrition in a long-term pot experiment with rice (Oryza sativa L.)

Summary The contribution of associative N₂ fixation to the N nutrition of lowland rice was estimated in a long-term pot experiment with ten consecutive crops of rice. The experiment comprised two N and two K levels with wet (WF) and dry fallow (DF) between the cropping seasons. Growth of N₂-fixing cyanobacteria was prevented. Greatest yields were obtained in the high NK fertilizer treatment, but with continuation of the experiment yields responsed more to DF than to WF. Nitrogenase activity, however, was favoured by WF. Higher K application increased and higher N application decreased nitrogenase activity. Under WF treatments the organic C and total N contents of the soil remained unchanged during the experimental period, but alternate drying and flooding in DF treatments caused a decline. Lower N fertilizer rates in the second five-crop period did not affect yields, but increased the ratio of N removed to N applied. For the ten-crop period the estimated N balance was positive in the low-N and negative in the high-N treatments. N balances were also established separately for both the first and the second halves of the ten-crop period. In the first period N losses were higher, and the N balance was mostly negative. In the second period only high-N combined with low-K fertilization resulted in a negative N balance. DF favoured N losses in the first but not in the second period. The highest N gain in the second period was found in the DF treatment with low-N and high-K application. In this treatment, nearly one-quarter of the N taken up by the above-ground parts of the plants could be ascribed to associative N₂ fixation. In the corresponding treatment with the higher N level and a 49% higher yield, the contribution of fixed N declined to less than 5%. When harvested straw contained more than 10 mg N g^–1, the N balance was mostly negative, while at N contents less than 10 mg N g^–1, the N balance was generally positive.     

杂交矮化长春花银川地区引种试验初探

在银川地区引种杂交矮化长春花Catharanthus niraana APRICOT等12个品种,进行种苗培育,观察其生长发育过程中的性状表现.探求各品种在本地区环境条件和栽培管理条件下,不同品种之间品质差异.结果表明：12个品种均能适应银川地区栽培;嫩枝带叶扦插成活率较高;且温室栽培生长发育良好.植株矮化,丰满,花大,色艳.     

后备优质晚稻新品种引种试验

进行8个优质稻新品种的引种试验,试验结果表明：8个品种均表现米质优,有7个品种生育期适宜、适应性较广,可作为宁德市蕉城区优质稻后备品种继续试种。     

播期和耕作方法对直播晚稻产量的影响

通过试验比较不同播期与耕作方法对晚稻产量的影响,以筛选出最佳播期和耕作方法。结果表明:7月20日播种的免耕直播晚稻产量和经济效益均较高,比同播期常耕直播稻增产稻谷125.1kg/hm2,增加产值175.5元/hm2,合计节本增收715.5元/hm2。     

Analysis on drag coefficients of bundled conductors under wind load

Drag coefficients of quad-bundled conductor under different wind speeds and attack angles are firstly determined by means of wind tunnel test. Meanwhile, the drag coefficients are obtained by numerical simulation method and the results are consistent with those by the wind tunnel test. Furthermore, cross flows around six-bundled and eight-bundled conductors are numerically investigated, and the drag coefficients are then determined. Compared with the determination method of wind load on conductor in current Chinese code and the IEC code for the design of transmission line, the drag coefficients defined in the Chinese code may be too large for bundled conductors, and may need to be adjusted based on further theoretical and wind tunnel test investigation.