解剖型锁定钛板与髓内钉治疗胫骨远端骨折的疗效比较

目的对比应用解剖型锁定钛板与髓内钉治疗胫骨远端骨折的临床疗效与并发症情况。方法自2019年9月至2021年9月，于中山大学孙逸仙纪念医院诊断为胫骨远端AO-A型骨折的手术患者纳入本研究，共32例。其中15例采用钛板螺钉治疗，17例采用髓内钉治疗。比较两组一般手术指标、骨折愈合时间、术后并发症发生情况、手术前后VAS评分及术后踝关节功能。结果患者均获得随访，随访时间10～20个月，平均12个月。髓内钉组手术时间、术中透视次数均长于钛板螺钉组，但术前等待时间、住院天数少于钛板螺钉组，统计学差异显著（P＜0.05）；两组骨折愈合时间相比，差异无统计学意义（P＞0.05）；术后6周，两组VAS评分均低于术前，统计学差异显著（P＜0.05）；髓内钉组与钛板螺钉组相比，手术前后VAS评分差异无统计学意义（P＞0.05）；术后6月AOFAS评分、术后1年踝关节活动度、并发症发生率髓内钉组优于钛板螺钉组，统计学差异显著（P＜0.05）；术后1年AOFAS评分两组差异无统计学意义（P＞0.05）。结论钛板螺钉与髓内钉均是治疗胫骨远端AO-A型骨折的有效术式，远期临床疗效无明显差异。髓内钉的软组织并发症较少，对踝关节活动度影响更小，康复更快，安全性更高，而钛板螺钉发生术后软组织感染的概率较大。我们建议在临床工作中，应该做好患者的术前评估，在把握适应症的前提下，髓内钉并发症更少，有一定优势

Cohort Effect and Factors Influencing Urban Seniors' Desire for Aged Support in Tianjin

通过分析天津城区老年人和准老年人养老意愿的调查数据,揭示出队列效应和年龄效应在养老意愿中起的不同作用。由于受重大社会变迁影响,“五零队列“在子女数目、受教育水平、是否下岗等生存状态上与“四零队列“显著不同。这些差异会影响他们未来的养老意愿和养老模式,政府应该针对“五零列队“的实际需要制定有效的养老政策。By analyzing the survey data to see seniors' and quasi-seniors' desires for aged support in Tianjin urban areas,the paper indicates that cohort effect and age effect have different influences on the desire.Due to the impact of major social changes,the "1950s Cohort" is remarkably different from the "1940s Cohort" in such aspects as the number of children,the level of education,whether being laid off,etc.These differences will affect their future mode of endowment and pension,so the government should base its endowment policies on the practical need of the "1950s Cohort".国家社会科学基金资助项目(12BRK009); 教育部重点研究基地基金资助重大项目(11JJD840012

a case study in implementing j2ee specification based on model checking

J2EE规范描述了当前开发应用服务器和分布式多层应用所遵循的技术蓝本.然而,它所使用的自然或半自然语言描述方式并不严格,易产生二义性,会影响J2EE应用服务器实现的正确性和应用服务器之间的兼容性.针对这一问题,本文以EJB2.1规范中的Timer Service为例,研究了一种基于模型检查技术设计与实现规范方法.首先根据规范的描述提出Timer Service的形式化模型,定义了Timer Service的行为;然后使用模型检查工具SPIN对模型进行分析与验证,不仅证明了模型符合规范要求,而且发现并修正

Distribution of heavy metals speciation and pollution in surface sediment from typical ecologically regions of Yantai coastal zone

运用Tessier连续提取法，对烟台海岸带3个典型生态敏感区表层沉积物重金属Cr、Cu、Cd、Pb、Zn、Ni的形态分布和污染状况进行了分析研究。结果表明，研究区域中河口区与排污口区重金属Cr、Cu、Cd、Zn和Ni的含量较高，尤其是Cd污染严重。养殖区基本符合海洋沉积物质量第1类标准；重金属Cr、Cu、Pb、Zn和Ni主要以残渣态为主，Cu和Pb的酸溶态所占比例较高，而Cd的可提取态比例较高，在河口区与排污口区高达90％，生物有效性最高

CoastalWetlands in the Yellow River Delta

运用Tessier连续提取法,对烟台海岸带3个典型生态敏感区表层沉积物重金属Cr、Cu、Cd、Pb、Zn、Ni的形态分布和污染状况进行了分析研究。结果表明,研究区域中河口区与排污口区重金属Cr、Cu、Cd、Zn和Ni的含量较高,尤其是Cd污染严重。养殖区基本符合海洋沉积物质量第1类标准; 重金属Cr、Cu、Pb、Zn和Ni主要以残渣态为主,Cu和Pb的酸溶态所占比例较高,而Cd的可提取态比例较高,在河口区与排污口区高达90%,生物有效性最高。

Harnessing instability for work hardening in multi-principal element alloys

The strength-ductility trade-off has long been a Gordian knot in conventional metallic structural materials and it is no exception in multi-principal element alloys. In particular, at ultrahigh yield strengths, plastic instability, that is, necking, happens prematurely, because of which ductility almost entirely disappears. This is due to the growing difficulty in the production and accumulation of dislocations from the very beginning of tensile deformation that renders the conventional dislocation hardening insufficient. Here we propose that premature necking can be harnessed for work hardening in a VCoNi multi-principal element alloy. Luders banding as an initial tensile response induces the ongoing localized necking at the band front to produce both triaxial stress and strain gradient, which enables the rapid multiplication of dislocations. This leads to forest dislocation hardening, plus extra work hardening due to the interaction of dislocations with the local-chemical-order regions. The dual work hardening combines to restrain and stabilize the premature necking in reverse as well as to facilitate uniform deformation. Consequently, a superior strength-and-ductility synergy is achieved with a ductility of similar to 20% and yield strength of 2 GPa during room-temperature and cryogenic deformation. These findings offer an instability-control paradigm for synergistic work hardening to conquer the strength-ductility paradox at ultrahigh yield strengths