Doubled Haploids of Cocoa (Theobroma cacao L.) 1. Observations of Fertility

Ovule and pollen fertility have been studied in doubled haploids of cocoa derived from spontaneous haploids, doubled by colchicine treatment. The two measures of fertility were very variable; occasionally, the levels were as high as those of the parent plant, but most were lower. The low fertility was not improved either by changing pollinators or after grafting. Pollen fertility also varied seasonally more in doubled haploids than in their parents. The lack of differentiation of embryo sacs seemed to be the cause of low values of ovule fertility. Both of these unfavourable characteristics were not observed in the progeny of doubled haploids, The low fertility is described in terms of homozygote depression, forced, on normally allogamous plants, its consequences for the use of doubled haploids in the production of hybrid seeds are discussed.     

当前国际油气管道工业的发展动向

通过统计和分析第三次国际管道会议发表的论文，对当前国际管道工业的发展问题进行了探讨，这些问题主要包括高压输送和高钢级管材的开发与应和、富气输送和管材的断裂控制、管道的缺陷监测、评估方法、管道完整性管理和管道风险管理等。目前我国在这些方面的研究与国际水平相比，还存在相当大的差距，应进一步加强在这些方面的科学研究。     

辽西山区水文地质特征

本文根据辽西山区地下水的赋存条件,水理性质和水力特征,将地下水划分为4种基本类型:松散岩类孔隙水、碎屑岩类裂隙孔隙水、碳酸盐岩类机溶水和其它岩类裂隙水。在此基础上又着重分析(?)地下水的富水程度,埋藏条件,水质特征和水资源评价。     

山羊实验性骨折愈合的X线观察

利用X线诊断技术,观察山羊的掌骨骨折愈合情况.结果表明:骨折愈合过程各期出现骨痂的最早时间,纤维性骨痂期平均为13d(最早者12d);骨性骨痂形成期平均为15.5d(最早者14d);骨性接合期平均为44d(最早者38d);骨痂改建期平均为72.5d(最早者70d).同时表明,同一骨骼的骨折,因骨折部位上下不同,达到各期愈合所经历的时间的差异明显,即掌骨上1/3组比掌骨下1/3组分别提前2,3,12和5d.     

考虑损伤时材料的断裂应力

工程结构的损伤分析、寿命预测及材料细观损伤机理与材料的强韧化研究，具有十分重要的工程意义，并具有广阔的发展前景。本文研究考虑损伤时材料的断裂应力，推导出了在表面能密度有限的情况下，损伤断裂应力的计算公式。     

F汽车方向机驱动轴的疲劳与断裂分析

F汽车进口后在索赔期内仅运行2800km,其方向机突然失灵,车与杨树相撞。在事故技术检查中发现方向机驱动轴破断。那么,该驱动轴是在车、树相撞中破断,还是在相撞前破断呢?本文对F汽车方向机驱动轴的破断进行了疲劳与断裂分析,其中有联接分析、受力分析、断口(宏观、微观和金相)分析,从而得出该件原为不合格件,断口为疲劳断口,是正常疲劳断裂的结论。致使索赔汽车谈判成功。     

FRACTURES OF THE DISTAL PHALANX AND ASSOCIATED SOFT TISSUE AND OSSEOUS ABNORMALITIES IN 22 HORSES WITH OSSIFIED SCLEROTIC UNGUAL CARTILAGES DIAGNOSED WITH MAGNETIC RESONANCE IMAGING

Ungual cartilage ossification in the forelimb is a common finding in horses. Subtle abnormalities associated with the ungual cartilages can be difficult to identify on radiographs. Magnetic resonance (MR) imaging findings of 22 horses (23 forelimbs) with a fracture of the distal phalanx and ossified ungual cartilage were characterized and graded. All horses had a forelimb fracture. Eleven involved a left forelimb (seven medial; four lateral), and 12 involved a right forelimb (five medial; seven lateral). All fractures were nonarticular, simple in configuration, and nondisplaced. The fractures were oriented in an axial proximal to abaxial distal and palmar to dorsal direction, and extended from the base of the ossified ungual cartilage into the distal phalanx. The fracture involved the fossa of the collateral ligament on the distal phalanx in 17 of 23 limbs. The palmar process and ossified ungual cartilage was abnormally mineralized in all horses. Ligaments and soft tissues adjacent to the ossified ungual cartilages were affected in all horses. The routine site of fracture in this study at the base of the ossified ungual cartilage extending into the distal phalanx suggests a biomechanical cause or focal stress point from cycling. The ligamentous structures associated with the ungual cartilages were often affected, showed altered signal intensity as well as enlargement and were thought to be contributing to the lameness. In conclusion, ossified ungual cartilages may lead to fracture of the palmar process of the distal phalanx and injury of the ungual cartilage ligaments.     

THE USE OF COMPUTED TOMOGRAPHIC THREE‐DIMENSIONAL RECONSTRUCTIONS TO DEVELOP INSTRUCTIONAL MODELS FOR EQUINE PELVIC ULTRASONOGRAPHY

Ultrasonography has gained increased utility to diagnose pelvic fractures in horses; however, internal pelvic contours can be difficult to appreciate from external palpable landmarks. We developed three‐dimensional (3D) simulations of the pelvic ultrasonographic examination to assist with translation of pelvic contours into two‐dimensional (2D) images. Contiguous 1 mm transverse computed tomography (CT) images were acquired through an equine femur and hemipelvis using a single slice helical scanner. 3D surface models were created using a DICOM reader and imported into a 3D modeling and animation program. The bone models were combined with a purchased 3D horse model and the skin made translucent to visualize pelvic surface contours. 3D models of ultrasound transducers were made from reference photos, and a thin sector shape was created to depict the ultrasound beam. Ultrasonographic examinations were simulated by moving transducers on the skin surface and rectally to produce images of pelvic structures. Camera angles were manipulated to best illustrate the transducer–beam–bone interface. Fractures were created in multiple configurations. Animations were exported as QuickTime movie files for use in presentations coupled with corresponding ultrasound videoclips. 3D models provide a link between ultrasonographic technique and image generation by depicting the interaction of the transducer, ultrasound beam, and structure of interest. The horse model was important to facilitate understanding of the location of pelvic structures relative to the skin surface. While CT acquisition time was brief, manipulation within the 3D software program was time intensive. Results were worthwhile from an instructional standpoint based on user feedback.     

塑性土壤破碎方法的比较

用改装的三轴剪切仪对拉伸、扭转、弯曲、直剪、切割和纯切割等基本加载方式进行了详细研究。结果表明,弯曲加载是需要最小力及最少能耗使塑性土壤破碎的一种有效的加载方式。     

削片机主轴的断裂与研制

削片机是木材废料和林区剩余物综合利用的重要机械设备,给林区带来了显著的经济效益和社会效益。黑龙江省友好木材综合加工厂Ⅱ号削片机,使用43个月后其主轴完全破断。本文在实地调查分析的基础上,对主轴进行了受力分析和断裂失效分析,研制了新主轴。投产一年来,通过对主轴的径向跳动测试和刀盘端面跳动测试表明,新主轴较原主轴的结构合理,工作正常,给工厂带来了较大的经济效益。