OMEGA算法在导弹振动工程中的应用

目的研究位移、速度和加速度谱之间的转换关系,给出三者功率谱密度之间的转换公式,进而用于导弹运输振动环境的设计。同时,研究加速度信号转换为振动位移的方法,并应用于导弹舱内单机设备安全间隙的设计。方法利用OMEGA算法,首先将加速度传感器测得的加速度时域信号转换成加速度频域信号,随后将加速度谱转换成位移谱,并计算位移谱中每个谱线对应的幅值、相位和圆频率,最后将各位移分量简单叠加得到振动位移的时间历程。结果采用该方法计算了高速公路上导弹的运输振动位移功率谱,并得到垂向、横向和纵向的峰-峰位移分别为3.32,0.46,2.14 mm。同时,计算了飞行环境下导弹舱内单机设备的振动位移,与所测得位移在幅值上相当,时域曲线形态一致。结论该方法能够很好地应用于导弹振动工程设计。     

Green research and development (R&D) investment and its impact on the market value of firms: evidence from South African mining firms

The importance of global corporate green research and development (R&D) investment is gaining momentum and South Africa is no exception. This paper examines growing economic perceptions that green financial and stock-market systems result in heightened corporate hyperopia and therefore increase long-term and future green investment associated with R&D. It reports on the findings of a survey of 14 South African mining firms listed on the Johannesburg Stock Exchange SRI index. The study found, that, these firms’ market value showed a positive association with Green R&D. It also revealed increased Green R&D activity among large mining firms in the country and that they are highly likely to maintain their level of such investment in the coming years. The study's outcomes thus add to the body of empirical knowledge on firm hyperopia in relation to corporate greening initiatives.     

Heat loss analysis: An approach toward the revival of parabolic dish type solar cooker

Present work investigates a noble approach toward the heat loss analysis of parabolic dish type solar cooker. Various experiments have been done on cooking pot to get the input parameter for calculation purposes. Cooking pot was kept at the focus of a parabolic dish type concentrator and repeated experiments have been done to measure solar radiation intensity (direct and Indirect) using a pyrometer, temperature at the focus of parabolic dish using a thermocouple and air velocity using hot wire anemometer to investigate the heat losses from the cooking pot. In the present article, a numerical approach has been performed to define the new parameter called performance index of the cooking pot which decides how the useful energy of working fluid inside the cooking pot approaches concentration ratio of the parabolic dish type solar cooker. The present analysis shows that the performance index varies from 15.45 to 17.66 and efficiency varies from 85.83% to 98.10% with the time of the day.     

Thermally chargeable supercapacitor based on nickel-coated nanoporous carbon

Nanoporous carbon is coated by pure nickel via an electroless plating method. The nanoporous carbon provides a high-surface-area substrate, leading to a large capacitance; the nickel surface layer is of a high work function, resulting in a thermally sensitive electrode potential. Such a system is ideal for thermally chargeable supercapacitor (TCS) system, which converts low-grade heat (LGH) to electrical energy. The specific energy per thermal cycle per gram of electrode mass is ~1.8 mJ, with a temperature difference of 50°C.     

长江中下游地区21世纪气候变化情景预测

利用IPCC数据分发中心提供的7个模式的模拟结果,分析了由于人类活动影响,温室气体(GG)增加以及温室气体和硫化物气溶胶(GS)共同增加时,长江中下游地区未来50～100年的气候变化情景.结果表明,长江中下游地区21世纪的未来温度变化与全球和全国一样,都将呈增加的趋势.GG作用下,2050年和2100年长江中下游地区的变暖幅度分别为2.2℃和4.5℃左右,比全国以及东部和西部地区的变暖幅度小;GS作用下2050年和2100年,其分别为1.2℃和3.9℃,总体上,长江中下游地区的变暖幅度低于全球与全国的变暖幅度.各个季节相比,春季和冬季的增温幅度最大,夏季最小,在两种情形下,长江中下游地区21世纪中期夏季温度将分别增加2.3和0.8℃,2100年将分别增加4.1和3.1℃.对降水变化的分析表明,GG作用下,长江中下游地区与全球、全国以及中国西部和东部地区相比,降水增加的幅度最大;GS作用下,降水增加趋势不明显;综合7个模式的模拟结果,GG作用下,春季和秋季降水增加最明显,夏季次之;GS作用下,长江中下游地区的年平均降水变化不明显,夏季降水增加.同时,本文还对长江中下游地区21世纪中期和末期的温度和降水变化的地理分布进行了分析,两种情形下,都是长江以北的增温幅度大于长江以南.GG作用下,春季长江中下游地区21世纪中期降水将增加5%～7.5%,夏季则是长江下游地区降水增加较大,将增加10%,而长江中游地区降水增加不明显;21世纪末,春季和夏季长江中下游地区的降水增加幅度都将加大,尤其是长江以南地区的降水增加最明显;考虑GG和GS的共同影响后,长江以南的地区降水增加,长江以北地区降水减少.     

水污染损失估算与治理水污染生态效益实例分析

企业排放污染物使其周围环境受到损失，根据环境所损失的价值与污染治理的费用，可以提出污染治理的生态效益，本文以沈阳某大型企业排放污水为例，主要运用了模糊数学法以及间接定价法和生态价值法对水资源价值进行核算，然后再进行费用——效益分析评价．结果表明对污水治理是具有明显生态效益的．     

浙江紫金牛属植物资源研究

对浙江境内原生分布的紫金牛属植物资源进行了调查和分析.在紫金牛属植物13个种类的引种驯化栽培、生物制药与园林花卉企业紫金牛属植物产业化开发调研的基础上,对其主要种类的药用价值和园林应用进行了评价,对该属植物的资源保护和开发利用提出了相应的对策.     

模拟环境传热性能试验室的研制

试验室由室外、室内构成,外室由空气处理机组模拟户外气候环境,内室配置温度、湿度、风速、热流计等传感器,测量由模拟空气调节器发出的热量,以对流和辐射的方式通过被测件传递到室外的能力。适用欧标、美标和国标试验要求。试验室用于测试各种部件和整体构件的环境传热性能,以减少空调能耗,提高节能水平。     

器件温度测试的影响因素

本文从器件用热像仪的测温过程、常用公式出发,针对测温条件进行了探讨,对公式里面的指数n的取值进行了推算。认为n可取4,但常数C和指数n的取值与波长范围和温度范围有关,要匹配。同时对IC温度分布的精确测量条件也进行了总结。