马歇尔交叉价格确定法质疑——为建立完整的价格确定式N/rT-X/Y探源

本文在对马歇尔的交叉价格确定法进行分析的基础上 ,指出了其价格理论在方法和理论上所存在的不足之处 ,进而提出了N/rT -X/Y价格确定式。

An Expansion of Boundary Theory and the Application of Joint Condition

The manuscript reviews the history and quo of the theory of Timoshenko’s method in stability analysis of compressive levers first, taking an example to explain the m-simulation method and putting forward the 3rd-7th boundary conditions demonstrating their superiorities in improving the precision through examples, followed by proposing and applying the join conditions in the stability analysis of combined axial force compressive levers gaining success. Through a brief example showing the effect of some related theories in a simple structural stability analysis, its application prospect is discussed.

A Preliminary of Dynamic Stability Analysis

On account of the traditional method in hybrid stability analysis being too rough, a new method of taking dual or single mode was put forward for 4 typical levers in the hybrid stability analysis respectively and transited to the dynamic analysis smoothly. After verifying the superiority of the method through examples, the broad application prospect would be given in the end.

后颅窝血管母细胞瘤CT、MRI表现及临床病理学研究

目的:探讨后颅窝血管母细胞瘤的CT、MRI及病理特点。方法:回顾性分析经病理证实的55例手术治疗的后颅窝血管母细胞瘤的临床症状、CT、MRI以及病理特点。结果:囊结节型CT多为低密度影,瘤结节为高密度影;MRI中囊液多表现为长T1、长T2信号,瘤结节多表现为等T1、等或长T2信号,增强均匀。实质型肿瘤CT呈高密度影或混杂密度影,呈TIW等信号,T2W等或高信号,增强后明显均匀强化。结论:后颅窝血管母细胞瘤具有自身独特的影像学特征结合临床特点可与其他肿瘤进行鉴别。

贵黔高速鸭池河特大桥钢桁梁施工关键技术

贵黔高速鸭池河特大桥为主跨800m的钢桁-混凝土混合梁斜拉桥,中跨钢桁梁采用"N"形桁架。受地形、运输和工期等条件限制,该桥采用缆索吊机进行16m长钢桁梁节段整体悬臂拼装。施工中,在边跨增设主动张拉的背索,以抵消缆索吊机对该桥变形的影响;优化接头处高强螺栓施工的时间和顺序,以防止新节段安装时高强螺栓受剪;重视钢桁梁节段现场的预拼装、测量和误差调整工作,以确保16m长节段拼装精度;采用等值张拉法和群锚千斤顶张拉,以实现钢绞线斜拉索的索力均匀性和整体索力控制;优化斜拉索施工索力,以实现合龙口姿态的调整,采用温度自然合龙法,以实现高精度合龙。鸭池河特大桥合龙后主梁线形平顺,施工误差满足规范要求,该桥已于2016年7月建成通车。

HPLC测定金鸡菊中金鸡菊查尔酮含量

目的建立高效液相色谱法测定金鸡菊中金鸡菊查尔酮含量的方法。方法采用Inertsil ODS-3 C18柱(4.6 mm×250 mm,5μm),以乙腈-1%冰醋酸(80∶20)为流动相,流速1.0 mL/min,检测波长378 nm。结果金鸡菊查尔酮在0.4～4.0μg范围内与峰面积呈良好线性关系,回归方程为Y=31 213X-149 303(r=0.999 9),平均回收率为99.21%,RSD=1.70%(n=5)。结论本方法简便、准确、重复性好,可用于金鸡菊的质量控制。