浅海内波与声场起伏

本文对存在于尖锐负跃层浅海中的内波,及其引起的声场起伏进行了初步的实验研究,在3.6公里上测得的声场振幅起伏与内波活动有明显的关联性,但其统计特性不完全一致,所测内波温度谱接近于ω~(-3)而振幅起伏谱接近于ω~(-2),对引起振幅起伏之机制我们倾向于Desaubies的看法。     

空间过滤简正波的模拟实验研究

在侧壁无消声的波浪槽(70×2×0.6m~3)内,利用9根有水平指向性的长圆管换能器作阵元,实现了前四号简正波的空间过滤,定性地研究了简正波过滤阵抑制近场点源干扰的理论概念,并对起伏波浪表面对各号简正波振幅起伏的影响作了初步观察。     

掺Ti对ZnO纳米颗粒的微观结构与光学特性的影响

本研究利用溶胶凝胶法制备了Ti_xZn_(1-x)O纳米粒子,并且分析了Ti掺杂对ZnO纳米粒子晶体结构与光学特性的影响.微观结构分析得知Ti掺杂会使ZnO结晶较差,晶格常数与压缩应力增大,但可使晶粒缩小至5 nm左右.光致发光(PL)光谱分析得出Ti掺杂会造成氧空位缺陷减少,近带边发光(NBE)峰值蓝移,但NBE峰值强度增幅变化却不大.拉曼光谱分析表明Ti_xZn_(1-x)O的结晶品质不佳且NBE峰值强度的增幅未完全依循多声子模态信号减弱而增强的规律,其原因是NBE峰值强度除受多声子模态信号影响外还受其它因素的影响.TC(002)值越高时样品的多声子模态信号会越弱,而NBE峰值强度增幅越大.     

Pure spin-current diode based on interacting quantum dot tunneling junction

A magnetic field-controlled spin-current diode is theoretically proposed, which consists of a junction with an interacting quantum dot sandwiched between a pair of nonmagnetic electrodes. By applying a spin bias V_S across the junction, a pure spin current can be obtained in a certain gate voltage regime,regardless of whether the Coulomb repulsion energy exists. More interestingly, if we applied an external magnetic field on the quantum dot, we observed a clear asymmetry in the spectrum of spin current I_S as a function of spin bias, while the charge current always decays to zero in the Coulomb blockade regime. Such asymmetry in the current profile suggests a spin diode-like behavior with respect to the spin bias, while the net charge through the device is almost zero. Different from the traditional charge current diode, this design can change the polarity direction and rectifying ability by adjusting the external magnetic field, which is very convenient. This device scheme can be compatible with current technologies and has potential applications in spintronics or quantum processing.     

All-electric-controlled spin current switching in single-molecule magnet-tunnel junctions

A single-molecule magnet (SMM) coupled to two normal metallic electrodes can both switch spin-up and spin-down electronic currents within two different windows of SMM gate voltage. Such spin current switching in the SMM tunnel junction arises from spin-selected single electron resonant tunneling via the lowest unoccupied molecular orbit of the SMM. Since it is not magnetically controlled but all-electrically controlled,the proposed spin current switching effect may have potential applications in future spintronics.     

微波诱导组装CuS@MoS2核壳纳米管及其光催化类芬顿反应研究

采用微波诱导组装,先将Cu纳米线硫化成空心CuS纳米管,再将片状MoS₂均匀插层并组装在CuS纳米管表面上,形成CuS@MoS₂核壳纳米管,用于可见光（λ>420 nm）催化类芬顿反应降解高浓度污染物罗丹明B（RhB）,30 min内降解率达100%.高活性归因于MoS₂独特的多层次结构增加了催化剂对光的吸收,提高了光利用率.同时,MoS₂与CuS之间形成的异质结结构有利于光生电子的转移,抑制了光生载流子的复合.更为重要的是构建了光催化与类芬顿反应的协同作用机制,光催化组分CuS中的铜离子与双氧水作用构成类芬顿循环体系并生成羟基自由基（·OH）,光生电子一方面与双氧水反应生成·OH,另一方面与MoS₂活化的分子氧反应产生超氧自由基（·O₂^-）,·OH和·O₂^-协同氧化污染物,可大幅度提高污染物去除效率.本工作开发的可循环光催化-芬顿反应体系,为实际污染治理开辟了新途径.