Iatrogenic fracture of the premaxilla during standing exodontia

This case report describes a 17‐year‐old horse that presented with a history of oral dysphagia secondary to buccal slab fractures and apical infection in two cheek teeth. During standing surgery to remove the diseased cheek teeth, the horse sustained a bilateral comminuted fracture of the premaxilla. An audible crack was followed by bilateral epistaxis. Subsequent radiography revealed minimal displacement at the fracture sites and the horse responded well to conservative management without the need for additional fixation techniques. One year later, the fracture appeared completely healed on repeat radiography. This is an uncommon complication of standing dental procedures necessitating the use of a speculum but is noteworthy and may be important to consider and inform owners in such aged cases.     

Racecourse fracture management. Part 3: Emergency care of specific fractures

In consideration of first aid of appendicular fractures in the horse, the literature is inconsistent and in some cases wrong or misleading. This in large part is due to misunderstanding of fracture mechanics and this paper aims to give a contemporary review of the subject. It is particularly relevant for fractures that occur on the racecourse or in horses in training which, due to their aetiopathogenesis, have substantial site and configuration commonality. However, the techniques discussed are frequently also applicable to non‐racing injuries. Clinical features are important in assessing horses on the racecourse when imaging techniques are limited. This paper highlights these in order to guide decision making.     

用断裂动力学对混凝土平面杆系进行破损评估

阐述用断裂动力学的方法对混凝土平面框架结构进行破损评估，建立含裂缝单元的刚度矩阵，利用断裂动力特征方程，对损伤部位的裂缝高度进行识别，直观地评价损伤的严重程度。通过对钢筋混凝土框架试验结果分析表明，本文的方法是可行的。     

玉米单倍体高自然加倍种质快捷轮选方法及高加倍瑞德核心种质的创制

基于DH系表现水平的轮回选择已被证明是改良玉米单倍体加倍能力的有效手段。本研究通过试验证明,在单倍体DH~0世代,基于优选单株组群开始轮回选择,同样也迅速提高了单倍体自然加倍能力。相比较基于DH系水平的轮回选择,每轮节约了1个世代,大幅度提升了选择效率。应用此方法构建了2个Reid群高加倍种质(群体及DH系),自然加倍率分别高达80%以上,已作为骨干核心种质应用于商业育种。"高自然加倍材料快捷创制方法"的成功突破,实现了高加倍种质与优异DH自交系同步创制。"瑞德类群高加倍核心种质的成功创制",为构建快捷高效的"单倍体自然加倍双轮回育种技术体系"奠定了坚实基础。     

喀斯特浅层裂隙土壤入渗特征及其影响因素

为探索喀斯特地下浅层裂隙土壤水分运移规律,通过野外调查、单环入渗试验探索裂隙土壤的入渗特性及入渗模型的适应性.结果表明:(1)裂隙土壤初始入渗率为21.06～57.90 mm/min,入渗时间20～60 min后达到稳定入渗(4.21～13.69 mm/min),且入渗初期到最后的稳渗阶段存在着较大降幅(40.89％～...     

基于ABAQUS有限元法的空洞树干强度分析

树木空洞可能会导致树木的死亡，同时，由于空洞树木抗风雪能力低，易在空洞处断裂，对人身和财物安全具有重大隐患。本研究通过软件Abaqus建立空心树干的三维模型进行有限元模拟分析，探索树干空洞的大小对树木强度和断裂破坏行为的影响。结果表明:1）树木发生弯曲和扭转破坏系数随载荷增加而增大，树干最外层的最大弯曲和扭转剪应力在断裂破坏前随载荷增加呈线性增加；2）当树干空洞发展到树干内外径比（α）为0.7时，随着空洞的继续增大其弯曲和扭转破坏系数会急剧增加，在α小于0.7时，弯曲和扭转破坏系数有一定的增加，但增加幅度较小；3）随着树干空洞造成内外径比的增加，树木发生扭转破坏的偏冠程度会逐渐降低。研究初步探明了树干空洞影响树木破坏行为和方式的力学机理，可为树木安全性评估提供一定的理论支持和依据。