Dependence of ion-pair induced self-pulsing in Er-doped fiber lasers on emission to absorption ratio

We show theoretically that the ion-pair induced self-pulsing in Er-doped fiber lasers depends largely on the ratio of emission to absorption cross sections, and can be significantly suppressed as this ratio is increased. Our experimental results agree qualitatively with this prediction. This result is important for stabilizing Er-doped fiber lasers where short-cavities and high-gain fibers are required.     

建筑构件积木式CAD软件研究

西方以混凝土坝内廓道施工样图设计阶段为例，论述水工建筑件积木式ＣＡＤ软件的必要性和积木模块ＣＡＤ软件的具体实现方法。     

强化乙烯生产管理提升企业竞争能力

回顾了中国石油天然气股份公司所属乙烯装置2002年的生产情况，总结了乙烯生产管理中取得的经验和存在的问题，并提出了今后乙烯生产管理的目标。     

广义物质平衡计算在凝析气藏开采动态预测中的应用

从经济的角度考虑 ,对小型凝析气藏衰竭式开采动态的预测往往不必或不值得进行数值模拟研究。常规物质平衡 (黑油 )计算方法只局限于黑油和干气藏 ,应用于凝析气藏则存在很大的误差。Walsh提出的广义物质平衡计算方法 ,可用于包括黑油、干气藏、挥发油气藏和凝析气藏在内的所有油气藏。文中将一个小型凝析气藏衰竭式开采动态的数值模拟结果与广义物质平衡计算结果进行了对比 ,结果表明 ,Walsh方法简便、应用更广泛 ,可用于规模较小、不适合进行数值模拟研究的凝析气藏的现场开发优化。     

Transmission loss allocation based on a new quadratic loss expression

This paper presents a derivation of a new quadratic expression for the transmission loss in a power system. The main advantage of this expression is the improvement in accuracy over the other existing approximations. Furthermore, this improved quadratic form allows the transmission loss to be expressed in terms of nodal power injections. This paper builds on the derived loss expression and proposes a bus-loss matrix. This matrix is useful in quantifying the interactions among different bus power injections and establishing a loss allocation scheme for individual buses. Numerical examples are used to illustrate the accuracy of the derived quadratic form and its use in loss allocation.     

草酸二异辛酯的合成

以酸化膨润土(SO42-/Bentonite)固体酸为催化剂、草酸和异辛醇为原料合成草酸二异辛酯。考察了焙烧温度对催化剂活性的影响。结果表明,焙烧温度为500℃时催化剂活性最好。考察了反应温度、原料配比、催化剂用量和反应时间等因素对酯化反应的影响,确定了最佳酯化反应工艺条件,即n(异辛醇)∶n(草酸)为3.5∶1、w(SO42-/Bentonite)为2.0%、反应温度140℃、反应时间3 h;在该条件下草酸的转化率达到96.4%。催化剂重复使用6次后,草酸的转化率仍可达到94.4%。     

一起500kV线路计量点事故隐患的分析与思考

本文简要介绍了500kV某回线计量点验收时发现事故隐患的过程,从电容式电压互感器本身结构出发,详细分析了产生事故隐患的原因、带来的危害等,并由此提出了计量点验收工作的重要性和必要性。     

The putative tumor suppressor gene on chromosome 5q for hepatocellular carcinoma is distinct from the MCC and APC genes

We have previously shown that the tumor suppressor gene for hepatocellular carcinoma (HCC) without cirrhosis may be located on chromosome 5q35-qter. In this study, we analyzed nine cases of primary HCC without cirrhosis using probes from the MCC and APC genes, which are in the region 5q21-22. None of the informative cases had allele loss detected by these probes, whereas the probe lambda MS8 for the region 5q35-qter showed allele loss in six out of six informative cases. The results confirm that the putative tumor suppressor gene for HCC without cirrhosis on chromosome 5q is distinct from the MCC and APC genes.