浅议现有变电站备用电源自投装置

采用现场统计数据分析目前备用电源自动化投入装置存在的问题,并探讨解决方向.     

出口纺织服装安全卫生项目抽查结果分析与思考

通过出口服装及其面料安全卫生项目抽查结果，分析其存在的问题，提出应对国际市场绿色技术壁垒的措施。     

l‐Citrulline Supplementation‐Increased Skeletal Muscle PGC‐1α Expression Is Associated with Exercise Performance and Increased Skeletal Muscle Weight

<section class="article-section__content" id="mnfr3251-sec-0010"> <h3> Scope</h3> l ‐citrulline has recently been reported as a more effective supplement for promoting intracellular nitric oxide (NO) production compared to l ‐arginine. Here, the effect of l ‐citrulline on skeletal muscle and its influence on exercise performance were investigated. The underlying mechanism of its effect, specifically on the expression of skeletal muscle peroxisome proliferator‐activated receptor‐gamma coactivator‐1α (PGC‐1α), was also elucidated. </section> <section class="article-section__content" id="mnfr3251-sec-0020"> <h3> Methods and results</h3> Six‐week‐old ICR mice were orally supplemented with l ‐citrulline (250 mg kg<sup>?1</sup>) daily, and their performance in weight‐loaded swimming exercise every other day for 15 days, was evaluated. In addition, mice muscles were weighed and evaluated for the expression of PGC‐1α and PGC‐1α‐regulated genes. Mice orally supplemented with l ‐citrulline had significantly higher gastrocnemius and biceps femoris muscle mass. Although not statistically significant, l ‐citrulline prolonged the swimming time to exhaustion. PGC‐1α upregulation was associated with vascular endothelial growth factor α (<i>VEGFα</i>) and insulin‐like growth factor 1 (<i>IGF‐1</i>) upregulation. <i>VEGFα</i> and <i>IGF‐1</i> are important for angiogenesis and muscle growth, respectively, and are regulated by PGC‐1α. Treatment with NG‐nitro‐l ‐arginine methyl ester hydrochloride (l ‐NAME), a nitric oxide synthesis inhibitor, suppressed the l ‐citrulline‐induced <i>PGC‐1α</i> upregulation in vitro. </section> <section class="article-section__content" id="mnfr3251-sec-0030"> <h3> Conclusion</h3> Supplementation with l ‐citrulline upregulates skeletal muscle PGC‐1α levels resulting in higher skeletal muscle weight that improves time to exhaustion during exercise. </section>     

行星锥盘无级变速器滑动率的数值计算

推导了行星锥盘无级变速器几何滑动率的计算公式,提出了一种求解其滑动率的数值计算方法,在此基础上编制了自动求解程序,并给出了计算实例。     

Enzymatic Synthesis of l‐Ascorbyl Fatty Acid Esters Under Ultrasonic Irradiation and Comparison of Their Antioxidant Activity and Stability

A series of novel l ‐ascorbyl fatty acid esters were synthesized by catalization of <i>Novozym<sup>®</sup> 435</i> under ultrasonic irradiation and characterized by infrared spectroscopy, electrospray ionization mass spectra, and nuclear magnetic resonance. Their properties especially antioxidant activity and stability were investigated. The results showed that the reducing power, the scavenging activity of hydroxyl radical and 2,2‐diphenyl‐1‐picrylhydrazyl radical were decreased with the increase of the number of carbon atoms in fatty acid. The hydroxyl radical scavenging activity and reducing power of l ‐ascorbyl saturated fatty acid esters were better than that of tert‐butylhydroquinone. The induction period in lipid oxidation of l ‐ascorbyl saturated fatty acid esters and tert‐butylhydroquinone were longer than that of l ‐ascorbyl unsaturated fatty acid esters and l ‐ascorbic acid both in soybean oil and lard. Besides, the l ‐ascorbyl fatty acid esters showed different stabilities in different conditions by comparing with l ‐ascorbic acid, and the l ‐ascorbyl saturated fatty acid esters were more stable than l ‐ascorbyl unsaturated fatty acid esters in ethanol solution.