山岳型风景名胜区内基础设施建设项目对生态环境的影响分析

风景名胜区旅游资源的开发常伴随着对生态环境的影响,实例分析了某山岳型风景名胜区内基础设施建设项目对生态环境的影响,并依次提出了项目施工期和运行期生态环境影响减缓和恢复措施。分析结果可为类似建设项目的环境影响评价提供借鉴,为更好地落实各项生态环保措施及"三同时"制度提供依据。     

低压等离子体弧源离子渗氮

利用低压等离子体弧源离子渗氮技术,在约４００ ℃、４ ×１０ － １ Ｐａ 真空度条件下对奥氏体不锈钢、纯铁进行了低温渗氮表面强化处理。奥氏体不锈钢表面形成的渗氮层由氮在奥氏体中的过饱和单相固溶体组成,具有很高的硬度和良好的耐蚀性。纯铁渗氮层则由化合物层和扩散层组成。这种渗氮方法完全避免了工件表面产生弧光放电     

轴承-转子系统不平衡周期响应的稳定性和分岔

研究了轴承-转子系统的非线性动力响应及分岔,建立了滑动轴承支承的对称单圆盘柔性转子系统的运动微分方程,针对转子系统具有的局部非线性特征,将Newton-Raphson方法和Wilson-è法相结合,形成了一种求解转子系统不平衡周期响应的迭代方法.运用该方法使得非线性响应的迭代求解仅在非线性自由度上进行,并运用Floquet稳定性理论分析了转子系统周期响应的稳定性和分岔形式.以转速作为分岔参数,对轴承-转子系统进行计算分析.数值结果表明,系统主要发生倍周期分岔和准周期分岔,具有各种周期解共存、跳跃现象,随着转速的不断增加,系统周期解将发生倒分岔和再分岔.     

一个非局部组成型活度系数方程

根据前文提出的液体混合的通用Gibbs自由能模型,导得了一个两参数非局部组成型活度系数方程.它适用于各种小分子液体混合物和高分子溶液,并能由二元参数预测多元系汽液平衡.对小分子液体混合物的泡点计算结果表明,除了醇/烃系统外,计算准确度不逊于局部组成型活度系数方程.它对高分子溶液的适用性则明显地优于UNIQUAC等方程.     

工频脉冲激励条件下线形微波H2等离子体的Langmuir探针诊断

在金刚石膜的化学气相沉积过程中，使用脉冲电源激励的微波等离子体可以提高金刚石膜的沉积速率或金刚石膜的质量。本文使用Langmuir探针研究了在工频脉冲电源激励条件下形成的线形微波H2等离子体的状态和开关特性。实验测量了在使用一支磁控管单独激励和两支磁控管共同激励情况下的H2等离子体的状态参量，包括等离子体的空间电位‰、探针悬浮电位Vf、电子温度Te和电子密度ne随时间的变化，特别是讨论了H2等离子体参量在激励电源开启与关断瞬间的过渡特征。     

贵溪电厂1、2号炉后屏过热器爆管原因分析

对后屏过热器超温爆管进行了全面分析,介绍了解决后屏过热器超温的措施。     

Influence of morphology on photo‐degradation of low density polyethylene films

The effect of the morphology on photo‐degradation was investigated for low‐density polyethylene materials. For this purpose, films with different degrees of crystallinity and different degrees of orientation were prepared. For all the films, photodegradation was promoted at 336K for 12 days using a weather meter. The following results were obtained. There existed an induction period before degradation or chain scission. The induction period was longer for stretched films than for un‐stretched ones. Also, the rate of degradation became lower for stretched films. However, both the induction period and the rate of degradation hardly changed with heat‐treatment condition, that is, the degree of crystallinity. In the induction period, the density changed in a complicated manner. This complicated change must be due to the change in the molecular aggregation state of the amorphous phase. The rheological and GPC measurements indicated that photo‐degradation causes the lowering of molecular weight and the increase in higher molecular weight fraction, and consequently the broadening of molecular weight distribution. The lowering of molecular weight may be caused by chain scission and the increase in higher molecular weight fraction by the formation of crosslinks.     

液体内压的预测和新溶解度参数值

引　言在作者先前的工作[1]中 ,已由液体混合的热力学模型导得一个比Ｓｃａｔｃｈａｒｄ -Ｈｉｌｄｅｂｒａｎｄ正规溶液理论更加严格的过量Ｇｉｂｂｓ自由能表达式 .据此 ,定义了一个新的溶解度参数Δ =λ/ｍ =δ2 /λ (1 )式中　δ2 =ΔＶａｐ Ｕｍ/Ｖｍ,为液体的内聚能密度 ;λ =ｐ1/2ｉ ,为液体内压的平方根 ;ｍ =ｐｉＶｍ/ΔＶａｐＵｍ,为Ｈｉｌｄｅｂｒａｎｄ参数 .不难看出 ,当ｍ =1时 ,Δ =δ ,故传统的Ｈｉｌｄｅｂｒａｎｄ溶解度参数δ只是式( 1 )的一种特殊情况 ,由于一般液体的ｍ不等于1 ,故Ｈｉｌｄｅｂｒａｎｄ溶解度参数必须…     

A high-linearity and high-resolution delay line structure with a calibration algorithm in delay-based LINC transmitters

In order to overcome the bottleneck of low linearity and low resolution, an improved delay line structure is proposed with a calibration algorithm to conquer PVT (process, voltage and temperature) variations for an all-digital design. The chip is implemented in 0.13 μ m CMOS technology. Measurement results show that the proposed structure with the calibration algorithm can evidently improve the linearity and resolution of the delay line. The delay resolution is 2 ps and the root mean square jitter of the delay is 4.71 ps, leading to an error vector magnitude enhancement of 1.32 dB.     

Estimating the Probability Density Function of Remaining Useful Life for Wiener Degradation Process with Uncertain Parameters

International Journal of Control, Automation and Systems - The effective prediction of remaining useful life is essential to realize system failure diagnosis and health management. The existing...