Transforaminal lumbar interbody fusion for traumatic lumbar spondylolisthesis

To evaluate the clinical outcome, effectiveness and safety of the surgical management of traumatic lumbar spondylolisthesis with transforaminal lumbar interbody fusion (TLIF) with short segmental instrumentation fixation. A retrospective review of a consecutive series of 24 patients with traumatic lumbar spondylolisthesis treated with TLIF procedure was carried out. Intraoperative spinal cord monitoring was used to confirm the peripheral neural function intact during the reduction of the spondylolisthesis. Preoperative clinical and radiographic evaluation of all cases were originally collected prospectively. Data regarding blood loss, operative time, duration of hospital stay, radiographic fusion, instrumentation failure and clinical result were collected and observed at regular follow-up periods. All patients were engaged in high-energy accidents in the lower back and 16 patients had concomitant injuries. The mean operative time was 124 min, mean blood loss was 350 mL, and mean hospital stay was 6.5 days. There were no complications such as incision infection, cerebrospinal fluide (CSF) leakage and nerve root injury and so on. All patients demonstrated a solid lumbar interbody fusion within 4 months, and no evidence of spondylolisthesis correction loss, instrumentation failure and loosing. They all were completely asymptomatic, with normal neurologic findings, and had resumed their previous level of physical activities on the final follow-up. Meticulous clinical examination and careful imaging assessment could assist an early diagonosis in cases of traumatic lumbar spondylolisthesis. Performing open reduction and the TLIF procedure as soon as possible could restore segmental stability and painless function. The TLIF procedure was a safe, effective technique to treat traumatic lumbar spondylolisthesis.     

具有扭转自由度的五节点索单元非线性有限元法

常见的索单元不具有沿轴向的转动自由度,但是在研究输电线覆冰舞动时,轴向的扭转不可忽略,基于此,提出一种新的通用的五节点索单元非线性有限元模型.该模型具有转动自由度,并考虑轴向变形与扭转变形的耦合,采用四次多项式作为位移插值函数及单元形状函数,运用全Lagrangian坐标描述法,由虚功原理建立了有限元基本方程和单元切线刚度矩阵,集成后利用Newton-Raphson法迭代求解.这样建立的非线性有限元分析方法不仅适用于一般悬索结构的分析,也适用于输电线这类需考虑扭转的特殊悬索结构的分析.算例结果表明,方法正确有效,具有较好的通用性,适用于各类悬索结构的分析、设计.     

构建行业IP呼叫中心

从呼叫中心的概述和发展历程出发,介绍IP呼叫中心的优势,重点说明IP呼叫中心的行业应用组网及功能。     

地下工程施工中岩爆的形成机理及控制措施

岩爆是高地应力环境下地下工程开挖过程中容易产生的一种突发性地质灾害,直接威胁施工人员和设备安全.文章针对岩爆的形成原因和机理,结合工程实例,提出了岩爆洞室开挖的施工防治措施、施工组织及工艺流程,可为高地应力条件下地下工程的开挖提供借鉴和经验.     

基于80C196列车超速防护系统测试仪的研制

采用80C196微处理器研制的新型列车超速防护系统测试仪不仅可用于列车运行控制系统的研制和生产过程中,而且也可用于现场维护,可模拟列车各种运行环境及可能出现的故障,可手动测试也可自动测试,随时给出被测系统的工作状况。作者主要介绍这种测试仪的功能,系统结构和实现方式。     

海军基地舰船维修器材管理体制的结构熵评价

以结构熵理论为基础,分析海军基地舰船维修器材管理体制的组织结构对系统内信息流的影响,从信息的角度对系统组织结构的有序度进行评价,引入信息流的时效和质量的概念,建立可以进行管理体制结构优化设计和进行定量评价的系统结构有序度计算的时效质量模型;并给出效质有序度的详细计算步骤,最后辅以实例.     

基于知识库的舰船智能化设计系统

为了提升数字化造船的科学性,提出基于知识库的舰船智能化设计系统,采用实体—属性—联系的数学模型进行知识表达建立知识库的层次结构,根据支持度确定多维数据关联与分类规则,针对不同专业设定不同的支持度阈值,提高求解最优性,并以多知识库集成模型数据分析为主体,构建一个综合性能分析系统架构模式。仿真分析数据证明,该系统结合数据挖掘与联机数据分析,实现了综合的决策融合,增强了数据的分析能力。通过该系统将舰船设计研发相关的技术、流程、经验和数据等资源进行有效管理,可以有效提升数字化造船水平。     

An integrated model system and policy evaluation tool for maximizing mobility under environmental capacity constraints: A case study in Dalian City,China

This paper presents an integrated model system for mobility maximization based on a quantified specification of environmental capacity, and evaluates policy interaction and effectiveness by simulating a number of policy scenarios. The system is designed to specify the maximum level of car ownership and number of trips by private and public modes subject to an environmental capacity constraint defined as the frontier emission under maximum system efficiency. Four types of hypothetical policies (population change, urban sprawl, land-use pattern and network improvement) are designed and the effects of 13 policy scenarios are simulated using data of Dalian City, China. Results reveal that the integrated model system reacts sensitively to policy interventions. The urban sprawl reflected in a changing residential distribution from central to suburban areas is most instrumental from the perspective of pollution alleviation. If the goal is to simultaneously reduce emissions while accommodating mobility, two combinational policy scenarios outperform all others.     

基于Hough变换的被动声纳航迹起始

航迹起始是航迹处理中的首要问题.研究用批处理技术中的Hough变换方法来创建航迹起始,把航迹上的观测点变换为参数空间的对应曲线,充分利用一段时间内的目标观测数据,通过Hough变换排除大量的杂波点,在低信噪比下也能从背景噪声中提取目标的航迹特征,在参数选择理想的情况下,起始精度较高,仿真试验证明了有效性.     

航向动态性能标校检测系统

提出了航向动态精度标校检测方法,给出了具体实施方案。该方案能解决陀螺导航装备出厂前或维修后的动态性能测试问题,对保证装备质量有着重要意义。