Size-dependent ignition temperature of metallic compounds fabricated by self-propagating high-temperature synthesis

Considering the diffusion reaction at solid interfaces, the ignition temperature of compounds fabricated by self-propagating high-temperature synthesis (SHS) is modelled with the help of size-dependent activation energy. As reactant size decreases, ignition temperature also decreases. This is because of increased contact areas between the reactants and the lowered diffusion barrier, both of which must be calculated specifically for reactants in nanoscale. The model predictions and experimental results are consistent for some metallic compounds.     

银杏叶化学组分群动态FTIR指纹图谱研究

比较了相同产地不同月份与相同月份不同产地银杏叶的FTIR图谱,研究了银杏叶化学组分群随气候、季节、地域等的差异而呈现出的动态分布规律。结果表明,从4月份到10月份,银杏叶内化学组分群呈现动态分布与变化,其变化在6月16日,9月1日,10月4日3个时段。5月份所采集的不同产地银杏叶的化学组分群分布基本一致。这在银杏叶药材种植质量管理规范(GAP)基地的建设、确保银杏叶原料的稳定性以及其后各类相关指纹图谱的研究及制定等方面具有重要意义。     

Centrally controlled quantum teleportation

Through designing a quantum communication network, we propose a protocol for the teleportation between multiple senders and multiple receivers via only one controller. In order to rationally employ the quantum entanglement resources, the controller shares the entangled state with every sender, while there is no directly shared entanglement link between sender and receiver. The security is analyzed in detail. Moreover, this protocol reduces the classical communication cost in the public channel by means of the coding.     

Extended Bose-Hubbard model with pair hopping on triangular lattice

We study systematically an extended Bose-Hubbard model on the triangular lattice by means of a meanfield method based on the Gutzwiller ansatz. Pair hopping terms are explicitly included and a three-body constraint is applied. The zero-temperature phase diagram and a variety of quantum phase transitions are investigated in great detail. In particular, we show the existence and the stability of the pair supersolid phase.     

焦化区土壤苯并（a）芘的污染状况

采用同步荧光光谱法对焦化厂附近不同距离采集的土壤样品中苯并（a）芘含量进行了检测。结果表明,苯并（a）芘的含量在距离焦化厂200m左右处出现最大值,检测结果与当地风向具有相关性。采用大气污染扩散模型对焦化厂焦炉无组织烟气中苯并（a）芘扩散浓度和距离进行了计算,结果与土壤中苯并（a）芘的检出规律具有一致性。     

Periodic intensity variations on the pulse-train of a passively mode-locked fiber ring laser

We investigate the evolvement of the periodic intensity variations of the pulse-train in a fiber ring laser mode-locked by the nonlinear polarization rotation technique. It is found that the phenomenon of such intensity fluctuations is related to the orientation of the polarization controllers when the pump power is fixed. The numerical results show that the mechanism of the periodic intensity variations is caused by the interaction of the nonlinear polarization rotation and the passive polarizer in the cavity.     

In-situ thermal crosslinked PA66/β-cyclodextrin/PA66 nanofibrous membranes with high mechanical strength for removal of heavy metal ions by flow through adsorption

β-cyclodextrin (β-CD) based materials have been studied widely as adsorbents and filter membranes for removing pollutants in air or water applications. The present study aimed to develop a sandwich structure of eletrospun nanofibrous membrane based on β-cyclodextrin and PA66 to achieve the high mechanical strength and flow-through adsorption of heavy metal ions in water. The surface and cross section morphology of PA66/β-cyclodextrin/PA66 nanofibrous membranes (PA66/β-CD/PA66 NMs) were examined using scanning electron microscopy (SEM). The physicochemical and mechanical properties of PA66/β-CD/PA66 NMs were analyzed by differential scanning calorimetry (DSC), thermogravimetric (TG) analysis and universal testing machine. The diameter of β-CD and PA66 electrospun fibers are 300–400 nm and 20–40 nm respectively. PA66/β-CD/PA66 NMs show a loosely arranged fibers and layer by layer structure. The tensile strength increases remarkably for PA66/β-CD/PA66 NMs, from 1.33 MPa of β-CD NMs to 23.17 MPa and the Young's modulus increases from 34.8 MPa to 253.3 MPa. The mechanical behavior of PA66/β-CD/PA66 NMs is a typical brittle fracture, and its microcosmic fracture diagrams are also involved. TGA/DSC results confirm the thermal crosslinking reaction is effective and complete. On the basis of SEM, DSC, TG and mechanical behavior analysis results, the molecular mechanism of in situ thermal crosslinking reaction is discussed. Fe³⁺、Ni²⁺ were used to confirm the ability to absorb heavy metal ions of PA66/β-CD/PA66 NMs. In conclusion, PA66/β-CD/PA66 NMs could be a promising solution for removal of metal ions by flow-through adsorption.