A novel method for camera external parameters online calibration using dotted road line

On board camera is the most important information source for driver assistant application which is based on computer vision. One problem for on board camera is that the external parameters are easy to be changed when moving on the road. Traditional method either calibrates external parameters offline or calibrates external parameters semi-online, which both need human intervention. By observation, it is found that corner connection of dotted road lane can form two groups of parallel lines. Using this geometric characteristics and through theoretical derivation, a novel online camera external parameter calibration method is proposed which focus on the situation when vehicle is moving. The pro of this method is that it maintains relatively high calculation accuracy and more important, it does not require any human intervention in whole calibration process. Experimental and comparison results show that this method is simple and have accurate results which fully meet the requirements of practical application.     

积层线路板用液态感光成像油墨的应用研究

研究了积层线路板油墨的组成配方、制备和应用工艺,分析了不同预烘时间对油墨分辨率的影响以及过显和显影不足问题的形成,并从生产和实际操作的角度,提出了解决的方案。利用聚苯醚改性的环氧树脂,应用于油墨的配方中,改善了油墨固化后绝缘材料的耐热性、介电性等主要性能。油墨中改性环氧树脂的质量分数为13.0%时,固化后绝缘材料的玻璃化温度可达184.22℃,介电常数为3.19,介质耗损因数为0.019,可以作高频积层线路板的绝缘层。     

FINE CONTROL OF HZSM-5’S PORE-OPENING SIZE BY A NEW CVD METHOD

A new CVD method without vacuum condition(CVDWV)was designed in this study,ithad been found that by modifying the flow rate of the carrier gas(N_2)and the temperature of sur-face reaction,silicon saturator and sample tube,the amount of silica deposited on the external sur-face of the zeolite could be precisely controlled,The changes in the physicochemical properties ofzeolite,such as pore-opening size,acidity and reaction property were investigated.The results ob-tained showed that:modification of the improved CVD method did not change the internal structureand acidity of the zeolite,but could bring about significant change of pore-opening size and reactionproperty as desired.     

基于自由运动一维标定物的多摄像机参数标定方法与实验

一维标定方法易于实现且标定效率高,为了克服现有一维标定方法的一些不足,本文提出一种用一维标定物标定多摄像机内外参数的方法,首先进行两两标定,在此过程中,假定主点坐标近似已知而仅考虑畸变、焦距、旋转和平移等参数,接着利用基本矩阵及一维标定物上特征点之间的几何约束,估计两摄像机的内外参数,两两标定完成后,采用Dijkstra最短路径法和捆绑调整对多摄像机系统进行全局标定(含主点坐标),仿真和真实实验表明本文的方法是切实有效的.     

Phosphate sorption approach for determining phosphorus requirements of wheat in calcareous soils

Five field experiments involving P application rates from 0 to 66 kg P ha^–1 were conducted on irrigated wheat at Tandojam, Pakistan. The soils belonged to two great soil groups, Torrifluvent and Camborthid. All soils were calcareous. Olsen-P contents ranged from 3.5 to 6.3 mg P kg^–1. Phosphate sorption curves were developed for soils from control (no P) plots at each site. Concentrations of P in solution established by fertilization in the field as estimated from the sorption curves ranged from 0.008 to 0.16mg P L^–1. Actual grain yields were converted to relative grain yields and plotted against corresponding concentrations of P in solution. Yield response to P application was obtained in each experiment. Control plot yields ranged from 57 to 89% of maximum yield of respective experiments. Phosphorus requirements of wheat were 0.032 mg L^–1 for 95% yield as determined from a composite yield response curve. Predicted quantities of P required to attain 0.032 mg P L^–1 ranged from 18 to 29 kg P ha^–1. The results of the study suggest that the P sorption approach can be used as a rational basis for making P fertilizer recommendations for various soil-crop combinations.     

涂料原料和涂层厚度对反射隔热保温性能影响研究

通过研究涂料配方中所用乳液、颜料、常规填料和隔热填料在红外灯下的反射、隔热和保温性能，发现高折射率的二氧化钛和含有微孔的硅藻土具有最佳的反射和隔热保温效果，轻质碳酸钙和重质碳酸钙具有一定的隔热保温作用，而理论上具有隔热保温效果的填料海泡石等并没有预期的效果。涂层厚度对隔热保温效果具有一定影响，但是没有颜料和填料的影响大。隔热涂料使用的填料应含有硅藻土、二氧化钛以及一些常规的填料。     

开放型电石炉绝缘问题浅见

介绍了开放型电石炉绝缘的结构特点，分析了绝缘材料的运行条件，讨论了绝缘系统的设计问题，提出了绝缘测试的三种方法。     

40%毒死蜱微乳剂的高效液相色谱法分析

采用ODS–C18反相色谱柱,用高效液相色谱法测定40%毒死蜱微乳剂制剂含量。方法的相关系数为0.9998,标准偏差为0.0242,变异系数为0.06%,平均回收率为98.6%。     

Predicting external sulphur requirement of alfalfa from sulphate sorption isotherm of Tanzanian soils

For Tanzanian soils dominant in hydrous oxides of iron and amorphous ferri-alumino silicate, a 48-hour (hr) mixing period with the sulphate (SO₄) solution was adequate for a near-equilibrium condition. Although differing in their SO₄ sorption capacity, all the soils sorbed SO₄ at or beyond 1µg ml^–1 sulphur (S) concentration in the supernatant. Hydroxyl (OH) ions were displaced during SO₄ sorption as indicated by a significant positive correlation between the amount of sorbed SO₄ and the difference in pH values determined in 0.1N K₂ SO₄ and 0.1N KCl, i.e. the dpH values.In a greenhouse experiment, alfalfa was grown on eight soils at six adjusted S concentrations. Sulphur deficiency symptoms appeared in the control pots of those soils which were low in native sorbed SO₄, SO₄ sorption capacity and initial soil solution S concentration. Sulphur fertilization increased dry matter (DM) yield as well as response to applied S. The external S concentration, i.e. adjusted S concentration required for 95% of the maximum DM yield, ranged from 0.8 to 8.2µg S ml^–1 with values less than 2.0 on most of the soils. The external S concentration decreased hyperbolically as the SO₄ sorption capacity of the soils increased. The total amount of fertilizer S required to obtain the external S concentration in solution, and at the same time satisfy the SO₄ sorption capacity of the soil at the external S concentration (determined from the sorption isotherm) was defined as the external S requirement for the specified yield level of alfalfa. The external S requirement for 95% of the maximum yield of alfalfa varied from soil to soil due to differences in their capacity and intensity for S nutrition.Part of a thesis by the senior author for the MSc (Agric) degree of the University of Dar es Salaam     

低萃取及B级聚酯绝缘膜研究 Ⅰ．国内研制动态

介绍了开发低萃取及B级聚酯(PET)薄膜的意义和要求,回顾了国内研制的情况,同时对其发展进行了讨论。