Emission of underwater acoustic orbital angular momentum and data transmission

Emission of underwater acoustic orbital angular momentum(OAM) is studied as well as underwater acoustic communications with OAM multiplexing. Theoretical acoustic properties for circular phased array are analyzed based on point source theory. We optimize and design an array prototype based on cymbal transducer. The diameter of array prototype is 180 mm, the number of array elements is 10, and the working frequency is 25 k Hz. It emits acoustic OAM with topological charges-3 to 3. The favorable results provide the theoretical basis for emitting acoustic OAM with different topological charges. We encode on-off states of acoustic OAM with different topological charges according to ASCII code to realize underwater acoustic communications. The transmission results suggest that acoustic OAM with various topological charges have intrinsically orthogonal properties. This research will offer potential applications in underwater acoustic communications.     

利用有理形式的指数函数法解决非线性Jaulent-Miodek方程的一系列复孤波解(英文)

本文研究了非线性Jaulent-Miodek方程的行波解.利用有理形式的指数函数法,得到了一系列包括由三角周期函数和有理函数组合而成的新复孤波解。     

The Distinguished Charge-Trapping Capability of the Memory Device with Al2O3-Cu2O Composite as the Charge Storage Layer

A memory device Si/Al2O3/Al2O3-Cu2O/Al2O3/Pt is fabricated by using atomic layer deposition and r~magnetron sputtering techniques. The memory device including the composite of Al2O3 and Cu2O as the charge storage layer shows a distinguished charge trapping capability. At a working voltage of ±11 V a memory window of 9.22 V is obtained. The x-ray photoelectron spectroscopic study shows a shoulder from Cu2＋ ions around the peak of Cu1＋ ions. It is suggested that the charge-trapping mechanism should be attributed to the defect states formed by the inter-diffusion at the interface of two oxides.     

例谈高等代数中抽象性问题的教学

针对高等代数课程中概念和代数运算的抽象性特点,通过教学实例展示如何引导学生将直观想象转化为抽象认识.     

铁(Ⅲ)催化氯代炔烃水化反应合成α-氯代甲基酮类化合物

研究了Fe(Ⅲ)催化氯代炔烃水化生成α-氯代甲基酮化合物的反应,考察了催化剂的种类、酸的种类、反应温度以及溶剂对反应的影响.结果表明,采用Fe Cl3·6H2O(摩尔分数5%)和甲基磺酸(摩尔分数20%),在1,2-二氯乙烷溶剂中,氯代炔烃于80℃进行水化反应3 h,可以高产率得到α-氯代甲基酮产物.所得化合物的结构采用IR,1H NMR,13C NMR及MS等方法进行了表征.该水化反应合成方法简单、条件温和且收率良好,为合成α-氯代甲基酮提供了一种简便途径.     

CTS/纳米SiO_2吸附剂对低浓度稀土离子的富集与回收

通过CTS/纳米Si O2吸附剂对低浓度稀土离子的吸附实验,研究了吸附剂的吸附-解吸性能。在吸附温度为25℃,p H=5,Gd3+、La3+和Y3+初始浓度分别为45mg/L、37.5mg/L和27.5mg/L,吸附剂加入量为40mg等条件下,CTS/纳米Si O2吸附剂对稀土离子Gd3+、La3+和Y3+的饱和吸附量分别为22.3mg/g、17.8mg/g和12.9mg/g。采用Langmuir模型对吸附平衡实验数据进行了线性模拟,并测定了吸附等温线。研究表明,CTS/纳米Si O2吸附剂对稀土离子有很强的吸附效果,吸附率高达98%,可用盐酸解吸回收稀土离子,并且吸附剂可再生利用。     

大型仪器的维护与维修(249~252)粉尘对ICP-OES运行的影响及解决方法

通过对电感耦合等离子体发射光谱仪(ICP-OES)外部和内部富集的粉尘进行分析,确定粉尘的形态和粒径,从而对ICP-OES的外部和内部系统进行了更新改造,大幅减少了粉尘对仪器运行的影响,降低了ICP-OES的维护频率和日常维护费用,延长了仪器的使用寿命,为其他大型精密仪器设备的防尘工作提供参考.     

Hydrothermal Synthesis, Crystal Structure and Fluorescent Property of a Novel Polyoxometalate [H6MoVI8O27]·3C4N2H10

A new infinite three-dimensional framework structure of the title compound [H6Mo^VI8O27]·3C4N2H10 has been synthesized under mild hydrothermal conditions and characterized by elemental analyses, IR, fluorescent spectra and single-crystal X-ray diffraction. C12H36Mo8N6O27 crystallizes in the triclinic system, space group P1^- with a = 8.820（3）, b = 9.534（3）, c = 10.993（4）A, α= 99.985（17）, β = 106.65（2）, γ= 101.650（14）°,V = 840.6（5）A^3, Mr = 1463.99, Z = 1, Dc = 2.892 g/cm^3,μ = 2.993 mm^-1, F（000） = 702, the final R = 0.0676, wR = 0.1920 and S = 1.074 for 2196 observed reflections with I 〉 2σ（I）. The title compound exhibits a novel infinite three-dimensional （3D） framework composed of a [H6Mo^VI8O27] subunit and three dissociated piperazine fragments. The complex exhibits two strong fluorescent emission bands at ca. 417 and 440 nm （λex = 378nm） in the solid state at room temperature.     

Hydrothermal Synthesis,Crystal Structure and Fluorescent Property of a Novel Polyoxometalate [H_6Mo_8~(VI)O_(27)]·3C_4N_2H_(10)

A new infinite three-dimensional framework structure of the title compound [H6MoVI8O27]·3C4N2H10 has been synthesized under mild hydrothermal conditions and charac-terized by elemental analyses,IR,fluorescent spectra and single-crystal X-ray diffraction.C12H36Mo8N6O27 crystallizes in the triclinic system,space group P 1 with a = 8.820(3),b = 9.534(3),c = 10.993(4) ,α = 99.985(17),β = 106.65(2),γ = 101.650(14)o,V = 840.6(5) 3,Mr = 1463.99,Z = 1,Dc = 2.892 g/cm3,μ = 2.993 mm-1,F(000) = 702,the final R = 0.0676,wR = 0.1920 and S = 1.074 for 2196 observed reflections with I > 2σ(I).The title compound exhibits a novel infinite three-dimensional(3D) framework composed of a [H6MoVI8O27] subunit and three dissociated piperazine fragments.The complex exhibits two strong fluorescent emission bands at ca.417 and 440 nm(λex = 378 nm) in the solid state at room temperature.     

CaF2对硅酸三钙的制备及其生物活性的影响

采用固相反应制备不同CaF掺量的生物活性硅酸三钙(3CaO·SiO22,C3S),并研究CaF2对C3S的制备及生物活性的影响.化学滴定、TGA/DTA、XRD、SEM和FTIR的分析结果表明,在煅烧过程中,CaF2有效的促进CaCO3的分解,并能形成低共熔化合物,促进C3S的形成;存急冷过程中,CaF2抑制CS晶型转变和分解,CaF2有效提高固相反应制备C§的纯度;模拟体液(SBD浸泡实验结果表明掺与小掺CaF2的C3s表面分别在1 d和3 d内诱导形成诱导磷厌石,这表明掺CaF2可以提高C3S的生物活性.