闽西晚中生代基性脉岩稀土元素地球化学特征

利用稀土元素特征对闽西基性脉岩的成岩方式和岩浆演化机制进行探讨. 闽西基性岩脉的稀土元素参数与常量元素的协变关系表明岩浆在上升侵入过程中可能没有发生地壳混染作用,在成岩过程中结晶分异作用可能不明显;多种稀土元素协变关系表明闽西基性脉岩的成岩机制可能为上地幔部分熔融作用,基性脉岩的地幔源区可能曾经遭受过俯冲流体交代富集作用,这种交代可能与古太平洋板块俯冲密切相关,软流圈地幔上涌导致地壳拉张作用的发育.     

The effect of MWS polarisation on the morphology and electro-optical behaviour of normal-mode polymer-stabilised cholesteric textures

We investigate the process and the resulting properties of the curing electric-field-induced segregation of reactive monomers (containing polar groups) in a host liquid crystal. The obtained dielectric spectrum of these cholesteric liquid crystals (CLCs) reveals polarisation at low frequencies. This is a strong indication that charge carriers accumulate at the interface between the sample and the electrodes in these compounds and consistent with Maxwell–Wagner–Sillars (MWS) polarisation. A polymer film forms on the substrate with its thickness determined by the MWS polarisation strength. The SEM images show that the polymer network becomes less dense when MWS polarisation increases. The results are a higher operating voltage and faster response time.     

AO-resistant properties of polyimide fibers containing phosphorous groups in main chains

A series of polyimide fibers containing phosphorus element derived from (3-aminophenyl) methyl phosphine oxide (DAMPO) diamine was exposed to an artificial atomic oxygen environment which simulated the space environment in low earth orbit (LEO). The mass loss, surface morphology, chemical composition, and mechanical properties of the fibers before and after atomic oxygen (AO) exposure were compared in detail with a blank sample. Results showed that the phosphor-containing fibers demonstrated lower mass change and less tensile strength reduction. SEM results showed that the fibers with phosphorous element had relatively dense surface after AO exposure. Meanwhile, XPS results indicated that a passivated phosphate layer, which could protect the following under-layer from attacking by AO, was formed on the surface of the fibers. These results indicated that the incorporation of diamine (DAMPO) into the main chains could protect the fibers for avoiding further erosion from AO exposure. Hence, the phosphor-containing PI fibers exhibits potential application in space fields.     

Reaction kinetics in anionic copolymerization: A revisit on Mayo-Lewis equation

Reactivity ratio is a traditional parameter quantifying the reaction kinetics in copolymerization, which is important for potentially controlling microstructures of polymers and guiding the copolymerization process. Our recent experiments using tube-NMR technique enable us to in situ monitor the concentration profiles of the co-monomers during the anionic copolymerization process. This motivates us to revisit the Mayo-Lewis(ML) equation, which is the basis for derivation of reactivity ratio and has been extensively utilized in addition copolymerization. We found that although an explicit ML expression is desirable for ease of calculation and correlation with experimental data, it fails in our anionic copolymerization experiment as well as some data available in the literature. The origin is ascribed to the validity of the steady state assumption which is essential in the ML equation. This assumption can be released in anionic copolymerization and replaced by the fact that the overall concentration of the living chain ends keeps constant throughout the copolymerization. Alternative numerical method has been utilized to obtain the rate constants and consequently the reactivity ratios. Our work suggests that the ML equation should be applied with caution.     

Research on Optical Transmitter and Receiver Module Used for High-Speed Interconnection between CPU and Memory

With the development of the multicore processor, the bandwidth and capacity of the memory, rather than the memory area, are the key factors in server performance. At present, however, the new architectures, such as fully buffered DIMM (FBDIMM), hybrid memory cube (HMC), and high bandwidth memory (HBM), cannot be commercially applied in the server. Therefore, a new architecture for the server is proposed. CPU and memory are separated onto different boards, and optical interconnection is used for the communication between them. Each optical module corresponds to each dual inline memory module (DIMM) with 64 channels. Compared to the previous technology, not only can the architecture realize high-capacity and wide-bandwidth memory, it also can reduce power consumption and cost, and be compatible with the existing dynamic random access memory (DRAM). In this article, the proposed module with system-in-package (SiP) integration is demonstrated. In the optical module, the silicon photonic chip is included, which is a promising technology to be applied in the next-generation data exchanging centers. And due to the bandwidth–distance performance of the optical interconnection, SerDes chips are introduced to convert the 64-bit data at 800 Mbps from/to 4-channel data at 12.8 Gbps after/before they are transmitted though optical fiber. All the devices are packaged on cheap organic substrates. To ensure the performance of the whole system, several optimization efforts have been performed on the two modules. High-speed interconnection traces have been designed and simulated with electromagnetic simulation software. Steady-state thermal characteristics of the transceiver module have been evaluated by ANSYS APLD based on finite-element methodology (FEM). Heat sinks are placed at the hotspot area to ensure the reliability of all working chips. Finally, this transceiver system based on silicon photonics is measured, and the eye diagrams of data and clock signals are verified.     

Chemical‐Bonding‐Directed Hierarchical Assembly of Nanoribbon‐Shaped Nanocomposites of Gold Nanorods and Poly(3‐hexylthiophene)

Nanoribbon‐shaped nanocomposites composed of conjugated polymer poly(3‐hexylthiophene) (P3HT) nanoribbons and plasmonic gold nanorods (AuNRs) were crafted by a co‐assembly of thiol‐terminated P3HT (P3HT‐SH) nanofibers with dodecanethiol‐coated AuNRs (AuNRs‐DDT). First, P3HT‐SH nanofibers were formed due to interchain π–π stacking. Upon the addition of AuNRs‐DDT, P3HT‐SH nanofibers were transformed into nanoribbons decorated with the aligned AuNRs on the surface (i.e., nanoribbon‐like P3HT/AuNRs nanocomposites). Depending on the surface coverage of the P3HT nanoribbons by AuNRs, these hierarchically assembled nanocomposites exhibited broadened and red‐shifted absorption bands of AuNRs in nIR region due to the plasmon coupling of adjacent aligned AuNRs and displayed quenched photoluminescence of P3HT. Such conjugated polymer/plasmonic nanorod nanocomposites may find applications in fields, such as building blocks for complex superstructures, optical biosensors, and optoelectronic devices.     

Synthesis,Crystal Structure,and Electrochemical Properties of a Simple Magnesium Electrolyte for Magnesium/Sulfur Batteries

Most simple magnesium salts tend to passivate the Mg metal surface too quickly to function as electrolytes for Mg batteries. In the present work, an electroactive salt [Mg(THF)₆][AlCl₄]₂ was synthesized and structurally characterized. The Mg electrolyte based on this simple mononuclear salt showed a high Mg cycling efficiency, good anodic stability (2.5 V vs. Mg), and high ionic conductivity (8.5 mS cm^?1). Magnesium/sulfur cells employing the as‐prepared electrolyte exhibited good cycling performance over 20 cycles in the range of 0.3–2.6 V, thus indicating an electrochemically reversible conversion of S to MgS without severe passivation of the Mg metal electrode surface.     

A study on the optimal English speech level for Chinese listeners in classrooms

Speech intelligibility in classrooms affects the learning efficiency of students directly, especially for the students who are using a second language. The speech intelligibility value is determined by many factors such as speech level, signal to noise ratio, and reverberation time in the rooms. This paper investigates the contributions of these factors with subjective tests, especially speech level, which is required for designing the optimal gain for sound amplification systems in classrooms. The test material was generated by mixing the convolution output of the English Coordinate Response Measure corpus and the room impulse responses with the background noise. The subjects are all Chinese students who use English as a second language. It is found that the speech intelligibility increases first and then decreases with the increase of speech level, and the optimal English speech level is about 71 dBA in classrooms for Chinese listeners when the signal to noise ratio and the reverberation time keep constant. Finally, a regression equation is proposed to predict the speech intelligibility based on speech level, signal to noise ratio, and reverberation time.     

共轭高分子链中电荷迁移的热效应

从理论上研究了共轭高聚物链中在电场作用下极化子运动的热效应.基于SSH模型以及通过绝热动力学演化的方法,模拟了共轭高聚物链中极化子在电场作用下从链左端向右端运动的过程.晶格受到的热扰动作用假设为通过局域的晶格范围内原子位移的随机涨落来实现.结果发现,晶格中的局域热涨落对于运动中的极化子而言等效于一个势垒.势垒高度由高分子中受到热扰动的区域的范围大小以及该区域与其周围环境的温差来决定.当分子中存在热吸收不均匀的现象时,链内极化子迁移率在低电场范围内随电场的变化遵循对数曲线变化规律.     

2,6-萘二甲酸构筑配合物的研究进展

2,6-萘二甲酸是一个具有多个配位原子的线性刚性配体,迄今,已报道的2,6-萘二甲酸构筑的配合物有100多个,它们展现了丰富的拓扑结构和潜在的应用价值。本文总结了2,6-萘二甲酸配体的结构特点以及配位模式,并按照金属离子的种类对2,6-萘二甲酸配合物进行分类归纳总结。着重介绍了2,6-萘二甲酸配合物在气体吸附分离、光致发光、磁性及多相催化方面的应用性质,对该类配合物的发展前景进行了展望。