Bending Stress Analysis on Backlash Adjustable Worm Transmission

The full name of variable tooth thickness plane worm gear transmission is. Backlash adjustable plane worm gear with variable tooth thickness enveloping worm transmission, which is a new kind of accurate power transmission that is intervenient between traditional motion transmission and power transmission. Tooth surface equations of the variable tooth thickness plane worm gear transmission are deduced based on the theory of engagement. Basing on the result, the authors create a finite analysis model of backlash adjustable variable tooth thickness plane enveloping worm with perfect tooth shape by using I-DEAS software, and then has done finite element analysis of backlash adjustable variable tooth thickness plane enveloping worm transmission. Finally, the author drew a conclusion about distribution of principal stress and load distribution between teeth, which offer some references for strength and performance analysis of worm transmission.     

Study on Mismatched Engagement of Hourglass Worm Gearing with The Worm Generated by A Cone and The Wheel Generdted by A Straight Profile Hob

A method to make the hourglass worm gearing with the property of mismatchedpoint contact has been proposed.The worm and the hob of the worm gearing is generated by a coneand a straight line located on the cone respectively. The basic principle of the worm gearing has beenanalysed. The formulas for calcultating the machining parameters has been obtained. And the toothcontact of the worm gearing has been investigated.The result shows that this worm gearing could getopint contact well.     

Study of Tooth Contact and Kinematic Precision on Cone-Generated Double Enveloping Worm Gearing

The tooth contact and kinematic precision of cone-generated double-enveloping worm gearing with machining and assembling errors have been investigated. The influence of different errors on driving quality has been discussed. The assembling method to reduce or eliminate the influences of machining errors on tooth contact and kinematic precision has been proposed.     

Force Analysis on Meshing Surface and Stress Research of the Cone Roller Enveloping Worm Gearing Transmission

By using the finite element elastic contact analysis method combined with the I-DEAS engineering analysis software, this paper studies the strength of the cone roller enveloping worm gearing,which is a new type of worm gearing transmission,on SUN-4 working station. It also analyzes loading distribution among meshing gears, the contact force distribution along the contact line ,the bending stress distribution and the contact stress distribution of the cone roller enveloping worm gearing with three-tooth meshing instantaneously. Besides,it provides the theoretic basis in the further researches for the new type of worm gearing transmission.     

Studies on the Technologies of Drilling with Zero-tilling Machine of Wheat after Rice in Wetland

免耕机条播是沿湖涝洼湿地生态区稻茬麦的主要播种方式之一，为探讨其科学栽培技术，分别对免耕机条播稻茬麦的冬前苗，叶面积系数、后期根系活力、播期、播量和多效唑化控进行了研究。结果表明，与稻田套播相比，机条播小麦的基本苗降低了150万/hm2，冬前主茎叶片增加了0.8个，单株茎蘖增加0.9个，单株次生根增加1.4条，茎粗增加1.1mm，地上部鲜重增加0.17g，叶面积系数动态为：冬前0.8，起身1.6，拔节期4.0，挑旗期6.2，灌浆期4.0，后期根系活力分别增加1.21、1.02、0.47，使用多效唑第1、2、     

山东高粱品种资源农艺性状及营养品质分析

对山东省现有的1223份高粱地方品种资源的农艺性状和部分材料的抗逆性、抗病虫性以及籽粒的蛋白质含量、赖氨酸含量和单宁含量进行了分析,结果表明:农艺性状中株高以高秆品种最多,其次是特高秆品种,生育期集中在106～120d,千粒重以小粒品种和中粒品种最多,分别占34.59%、43.34%;穗长集中在20.1～35cm,穗粒重集中在30.1～70g;穗型以散穗最多,粒色以红粒为主,壳色以黑壳最多。高粱抗性中,已经鉴定的材料有2份耐盐性为1级,96.09%材料的耐盐级别为4、5级,有4份材料抗旱为1级,有2份材料对黑穗病免疫,多数材料不抗螟虫和蚜虫,但有9份材料抗螟性为1、2级;在已经测定的种质资源中有79.16%的材料蛋白质含量低于12.5%,有7份材料的蛋白质含量超过15%,有81.54%的材料赖氨酸含量在0.21%～0.40%之间,有4份材料赖氨酸含量超过0.45%,单宁平均含量0.645%,基本成正态分布,有101份材料含量低于0.1%。总之,山东省地方品种资源农艺性状、抗性、籽粒品质变异类型丰富,可以为高粱育种提供良好的种质资源。     

近代及现代黄河三角洲不同尺度地貌单元土壤盐渍化特征浅析

近、现代黄河三角洲近50%的土地为不同程度的盐渍化土。在土壤盐渍化过程中,地貌因素至观重要。地形的高低起伏,影响地面、地下径流的运动,土壤中的水分和盐分也就随之重新分配和积累。研究的目的是分析不同尺度下地貌单元之间土壤盐渍化特征差异及原因。为此,利用2002年5月23日到29日对近、现代黄河三角洲野外考察、GPS定点和土壤采样分析所得数据,对6个表征土壤盐渍化特征的参数（土壤的全盐量、pH值、有机质、Cl-/SO42-、HCO3-/(Cl-+SO42-)、(K++Na+)/(Ca2++Mg2+)）进行统计分析,并进行多个独立样本的非参数检验（Kruskal-Wallis Test和Median Test）,检验6个参数在同一尺度不同地貌单元之间是否有明显的差异,结果表明：（1）近、现代黄河三角洲土壤盐渍化程度严重,整体属于滨海氯化物型盐渍土类型,有机质相对缺乏,土壤偏碱性。随土层深度增加（0cm~10cm、10cm~30cm、30cm~60cm）,盐渍化程度逐渐减轻;（2）同一尺度下不同地貌单元之间土壤盐渍化特征存在差异。一般地,随尺度变小（从一级到四级地貌单元）,土壤盐渍化特征差异越来越明显,存在差异的参数也逐渐增加。一级地貌单元只有pH值明显不同,从二级地貌单元到四级地貌单元,3个土层土壤的全盐量随不同的地貌单元而有明显的差别,且随着土层深度的增加,HCO3-/(Cl-+SO42-)和(K++Na+)/(Ca2++Mg2+)也变得明显不同。这也说明不同地貌单元下盐分组成及离子比例、积盐、脱盐过程存在差异,且随土层深度增加差异越大。     

连作杂交晚稻精准条播长秧龄机插的生长及产量特性分析

为明确精准条播(precision drill sowing, PS)在连作晚稻长秧龄机插中的有益效果。本试验以甬优1540为供试品种,设置标准9寸秧盘横向16条(PS-16, 45.7 g盘^–1)和18条(PS-18, 60.5 g盘^–1)精准条播,并以传统撒播(broadcast sowing, BS, 60.5 g盘^–1)作为对照,同期播种,设置20、25、30和35 d 4个机插秧龄,比较分析各播种方式水稻秧苗素质、机插特性、群体生长及产量形成的变化。结果表明:(1)精准条播提高秧苗群体透光性,与撒播相比,精准条播提高了长秧龄秧苗的素质,增加了带分蘖秧苗的比例,其中PS-16秧苗素质最好,带分蘖秧苗的比例最高。(2)与撒播相比,精准条播显著降低机插漏秧率,提高机插取秧2～3株苗比例,PS-16和PS-18间差异不明显。秧龄延长增加机插秧苗伤根程度和伤苗率,降低秧苗存活率,其中PS-16的伤根程度和伤苗率增加幅度最小,机插秧苗存活率最高。(3)机插秧龄延长增加了秧苗缓苗返青天数进而推迟水稻生育期,各机插秧龄下, P...