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.     

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.     

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.     

金刚石薄膜制备和评价

采用平直钨丝作热解源,并借助钨丝支架的弹性恢复力,较好地解决了热丝热解化学气相沉积法(HFCVD)合成金刚石过程中热解丝的变形问题.样品独立加热,基片温度、钨丝温度、钨丝与样品基片距离均可独立调节.装置改进后,在Si(100)上合成了面积大约45mm×25mm的比较均匀的金刚石膜.用扫描电子显微镜(SEM)、Raman光谱和X射线衍射仪对制备的金刚石膜进行了分析.     

转变观念是润滑技术现代化的必要途径

探讨了国内润滑工作存在的问题，分析了近20年来润滑技术的发展状况，介绍了国内先进单位合理用油取得的效益和经验，提出用油现代化的看法。     

低相噪,低杂波数字锁相环路滤波器的设计

较详细地分析数字锁相频率合成器的相位噪声，着重用控制论方法对低相噪、低杂波锁相环的环路滤波器进行设计，并用某Ｓ波段频率合成器的实验结果进行了验证。