一种考虑静水压力和偏应力共同作用的相变临界准则

同时考虑静水压力和偏应力的影响,分别建立了“应力诱发”和“形变诱发”相变的临界准则．准则在主应力空间中给出的相变临界曲面呈现明显的拉压不对称性．在弹性阶段,偏应力对相变总是起促进作用．塑性屈服后,偏应力通过塑性功产生的温升影响相变临界面,从而对高温相到低温相转变起阻碍作用,反之起促进作用．静水压力对相变可能起促进作用,也可能起阻碍作用,取决于相变时材料的体积是膨胀还是收缩．建立的相变临界准则对准静态加载条件下的Fe-20％Ni-0．5％合金和Fe-30％Ni合金和一维应变冲击条件下的Fe-32％Ni-0．035％。C合金中的γ-α相变进行了拟合和预测,预测与实验结果有较好的吻合。在主应力空间中柱形屈服面可能与锥形相变临界面相交,从而在一定条件下将发生“形变诱发”相变和“应力诱发”相变间的转变,这一推论有待实验的验证。     

用于费-托合成的高分散型钴基催化剂*

负载型钴基催化剂是天然气基费托合成的一种重要催化剂,其金属分散度和活性位密度是决定费托合成反应活性和产物选择性（CH4%, C5+%）的关键因素。因此,提高金属钴的分散度和催化剂的还原度是提高金属钴的原子利用率、降低催化剂成本的一条有效途径。本文综述了近年来高分散型钴基催化剂的研究进展,重点探讨了催化剂制备方法、载体类型及贵金属助剂对催化剂分散度和还原性的影响,以及影响高分散型钴基催化剂的费托合成反应活性、产物选择性和反应稳定性的因素,并对负载型钴基催化剂今后的研究发展提出了一些建议。     

A Kuznetsov Formula for Kloosterman Sums on GLn

We prove a Kuznetsov sum formula for Kloosterman sums on GL _n corresponding to the big Bruhat cell. Using this formula, a weighted sum of Kloosterman sums can be expressed in spectral decomposition. A non-trivial estimate of the spectral side might lead to a proof of cancellations in sums of Kloosterman sums on GL _n.     

Holey Lamellar High-Entropy Oxide as an Ultra-High-Activity Heterogeneous Catalyst for Solvent-free Aerobic Oxidation of Benzyl Alcohol

The development of noble-metal-free heterogeneous catalysts is promising for selective oxidation of aromatic alcohols; however, the relatively low conversion of non-noble metal catalysts under solvent-free atmospheric conditions hinders their industrial application. Now, a holey lamellar high entropy oxide (HEO) Co_0.2Ni_0.2Cu_0.2Mg_0.2Zn_0.2O material with mesoporous structure is prepared by an anchoring and merging process. The HEO has ultra-high catalytic activity for the solvent-free aerobic oxidation of benzyl alcohol. Up to 98 % conversion can be achieved in only 2 h, to our knowledge, the highest conversion of benzyl alcohol by oxidation to date. By regulating the catalytic reaction parameters, benzoic acid or benzaldehyde can be selectively optimized as the main product. Analytical characterizations and calculations provide a deeper insight into the catalysis mechanism, revealing abundant oxygen vacancies and holey lamellar framework contribute to the ultra-high catalytic activity.     

基于RFID和指静脉识别的化学药品智能管理柜设计

为保障实验室中存放的药品安全, 提出一种基于射频识别(RFID)和指静脉识别的化学药品智能管理柜. 智能柜采用RFID、指静脉识别等物联网技术, 通过用户身份认证, 化学药品的自动识别、记录以及存储空间的智能控制, 实现实验室化学药品的高效安全管理. 样机实际测试结果表明, 系统可以较好地通过指静脉识别对使用者的身份进行认证, 也能够通过RFID快速识别化学药品; 系统智能化程度高, 各项功能完备, 可显著提高实验室化学药品管理能力.     

四苯基卟吩激发—重态衰变的“外部重原子效应”的研究

考查了在有芳烃卤代物RX(如氯苯、溴苯和碘苯)存在时,四苯基卟吩TPP的荧光衰变现象。基于荧光衰变动力学分析,发现:在RX和TPP之间生成复合物是引起重原子效应的一个基本步骤。荧光衰变的动力学参数则进一步表明:可观察的外部重原子效应主要是由于发生分子间电荷转移相互作用而引起的。     

Be(d,n)反应中子源能谱测量及应用

 利用中子飞行时间技术和BC501A液体闪烁探测器的粒子分辨特性,测量了0°方向、20 MeV氘束轰击厚金属铍靶反应产生的中子源能谱,测量的中子能谱范围为0.7～25.0 MeV。在60°方向放置芪晶体闪烁探测器,由刻度好的BC501A液体闪烁探测器归一校正后,用于中子源强度监测。利用Be(d, n) 反应中子源,采用单粒子灵敏度标定方法,实验标定了0.75~15.75 MeV能量范围内的薄膜闪烁探测器中子能量响应曲线,实验结果与蒙特卡罗模拟计算结果在8%的不确定度范围内一致。     

被动谐波锁模Er3+/Yb3+共掺双包层光纤环形腔激光器

 为了实现高重复频率和高功率的光脉冲,实验采用Er³⁺/Yb³⁺共掺双包层光纤作为增益介质,稳定的中心波长为976 nm的高功率半导体激光器作为泵浦源,利用非线性偏振旋转锁模技术,得到稳定的自起振锁模光脉冲。当泵浦功率为2.4 W时,激光器输出重复频率为8.829 MHz的连续锁模光脉冲,平均输出功率为52.5 mW,自起振锁模泵浦阈值功率为0.6 W,并观测到了稳定的高阶谐波锁模、调Q和调Q-锁模光脉冲输出。     

A proof of Selberg's orthogonality for automorphic L-functions

Let π and π′ be automorphic irreducible cuspidal representations of GL_m(Q_A) and GL_m′(Q_A), respectively. Assume that π and π′ are unitary and at least one of them is self-contragredient. In this article we will give an unconditional proof of an orthogonality for π and π′, weighted by the von Mangoldt function Λ(n) and 1−n/x. We then remove the weighting factor 1−n/x and prove the Selberg orthogonality conjecture for automorphic L-functions L(s,π) and L(s,π′), unconditionally for m≤4 and m′≤4, and under the Hypothesis H of Rudnick and Sarnak [20] in other cases. This proof of Selberg's orthogonality removes such an assumption in the computation of superposition distribution of normalized nontrivial zeros of distinct automorphic L-functions by Liu and Ye [12].     

Subconvexity bounds for Rankin–Selberg L-functions for congruence subgroups

Estimation of shifted sums of Fourier coefficients of cusp forms plays crucial roles in analytic number theory. Its known region of holomorphy and bounds, however, depend on bounds toward the general Ramanujan conjecture. In this article, we extended such a shifted sum meromorphically to a larger half plane Res>1/2 and proved a better bound. As an application, we then proved a subconvexity bound for Rankin–Selberg L-functions which does not rely on bounds toward the Ramanujan conjecture: Let f be either a holomorphic cusp form of weight k, or a Maass cusp form with Laplace eigenvalue 1/4+k², for . Let g be a fixed holomorphic or Maass cusp form. What we obtained is the following bound for the L-function L(s,fg) in the k aspect:

L(1/2+it,fg)k^{1−1/(8+4θ)+ε},