随着欧盟RoHS(the Restriction of the use of certain hazardous substances in electrical and electronic equipment)指令的正式实施,挪威的PoHS(Prohibition on Certain Hazardous Substances in Consumer Products)禁令也计划于今...随着欧盟RoHS(the Restriction of the use of certain hazardous substances in electrical and electronic equipment)指令的正式实施,挪威的PoHS(Prohibition on Certain Hazardous Substances in Consumer Products)禁令也计划于今年实施。为了能更好的理解这一新禁令,本文将对PoHS禁令进行解读。展开更多
The localized molecular orbital (LMO) theory is used to study the reaction mechanism of the isomerization reaction: H3PO→H2POH. The energy transition state (TS) of the reaction is also obtained by Powell’s mehtod us...The localized molecular orbital (LMO) theory is used to study the reaction mechanism of the isomerization reaction: H3PO→H2POH. The energy transition state (TS) of the reaction is also obtained by Powell’s mehtod using 6-31G basis set. The resluts show that the lone pair electrons of oxygen atom play an forortant role in this reaction.展开更多
文摘随着欧盟RoHS(the Restriction of the use of certain hazardous substances in electrical and electronic equipment)指令的正式实施,挪威的PoHS(Prohibition on Certain Hazardous Substances in Consumer Products)禁令也计划于今年实施。为了能更好的理解这一新禁令,本文将对PoHS禁令进行解读。
文摘利用多普勒雷达资料,结合探空和常规资料,对2 0 1 1年4月1 7日一次超级单体雹暴的流场和回波结构演变特征进行了详细研究,主要结果:该雹暴是在条件性不稳定和垂直风切变较大的环境条件下产生的右移风暴。雹云初生发展阶段,垂直剖面显示逐渐形成有组织化的斜上升气流促进雹云发展。成熟降雹阶段,雹云内形成一支强的斜上升气流和深厚的中气旋,主上升气流对应雹云的弱回波区。雹云维持典型的弱回波区—悬挂回波—回波墙特征结构。根据雷达径向速度和雹云移速订正得出的"零线"演变发现,随着雹云的发展,"零线"逐渐向悬挂回波靠近,并穿过悬挂回波,"零线"的走向为上翘式,附近"穴道"的汇集力较强,有利于降雹。通过对"零线"位置的判断可分析有利成雹的区域。根据高低空两层强回波的水平错位,利用两高度强中心连线所作剖面能快速准确得出特征剖面,并将0°C层以上6 k m高度处降雹潜势达到1 0 0%的4 5 d B Z的区域识别为成雹区,与降雹实况对比发现识别效果良好。
文摘The localized molecular orbital (LMO) theory is used to study the reaction mechanism of the isomerization reaction: H3PO→H2POH. The energy transition state (TS) of the reaction is also obtained by Powell’s mehtod using 6-31G basis set. The resluts show that the lone pair electrons of oxygen atom play an forortant role in this reaction.
