HADAR实验对活动星系核伽马射线辐射观测的预期研究

HADAR (High Altitude Detection of Astronomical Radiation)是一个基于大气切伦科夫成像技术的地面望远镜阵列,其采用大口径折射式水透镜系统来收集大气切伦科夫光,以实现对10 GeV—10 TeV能量段的伽马射线和宇宙线的探测.HADAR具有低阈能和大视场的优势,因此可以对天区进行连续扫描和观测,在观测活动星系核(Active Galactic Nuclei,AGN)等银河系外伽马射线源方面具有明显优势.本文研究了HADAR实验对AGN的探测能力.基于费米望远镜(Fermi Large Area Telescope,Fermi-LAT)的AGN源能谱信息,将观测能量外推至甚高能能段,同时加入河外背景光的吸收效应,以计算HADAR对AGN源观测的统计显著性.研究结果显示,HADAR运行一年时间,预计将有31个Fermi-LAT AGN源以高于5倍显著性被观测到,其中大部分为蝎虎状天体类型.     

Photoproduction of J/ψ in non-single-diffractive p+p collisions

Significant enhancements of J/ψ production at very low transverse momenta were recently observed by the ALICE and STAR collaborations in peripheral hadronic A+A collisions. The anomalous excess points to coherent photon-nucleus interactions in violent hadronic heavy-ion collisions, which were conventionally studied only in ultra-peripheral collisions. Assuming that the coherent photoproduction is the underlying mechanism responsible for the excess observed in peripheral A+A collisions, its contribution in p+p collisions with nuclear overlap, i.e. nonsingle-diffractive collisions, is of particular interest. In this paper, we perform a calculation of exclusive J/ψ photoproduction in non-single-diffractive p+p collisions at the RHIC and LHC energies based on the pQCD motivated parametrization using the world-wide experimental data, which could be further employed to improve the precision of the phenomenological calculations for photoproduction in A+A collisions. The differential rapidity and transverse momentum distributions of J/ψ from photoproduction are presented. In comparison with the J/ψ production from hadronic interactions, we find that the contribution of photoproduction is negligible.     

乙酸异丙酯的合成

以乙酸和异丙醇为原料,硫酸氢钠为催化剂,合成了乙酸异丙酯;考察了反应时间、酸醇比、催化剂用量、带水剂用量对酯化率的影响,确定了最佳酯化反应条件:反应时间60min,酸醇的物质的量的比1∶0.8,催化剂用量0.8g,带水剂用量8mL.在最佳反应条件下,酯化率最高可达84.3%.     

Rapidity dependence of global polarization in heavy ion collisions

We use a geometric model for hadron polarization in heavy ion collisions with an emphasis on the rapidity dependence.The model is based on the model of Brodsky,Gunion,and Kuhn,as well as the Bjorken scaling model.We make predictions regarding the rapidity dependence of global Λ polarization in the collision energy range of 7.7-200 GeV by assuming the rapidity dependence of two parameters,κ and <ρτ>. The predictions can be tested by future beam-energy-scan experiments at the Relativistic Heavy Ion Collider of Brookhaven National Lab.     

利用H3PO4液层侧面红外热像研究YBCO高温超导薄膜的激光辅助刻蚀特性

利用红外热像实时监测系统,获取钇钡铜氧激光辅助化学刻蚀中H₃PO₄液层的侧面红外热像,研究了其溶液温度分布与热对流特性,并对红外监测数据与钇钡铜氧薄膜激光化学刻蚀特性的关系进行了分析.主要实验结论包括:红外灰度图可真实反映溶液的温度分布和热对流情况,为激光化学刻蚀的热环境分析提供有价值的红外监测数据;通过任意时刻钇钡铜氧表面生成热流所到达高度的分布情况和该时刻的红外灰度图,分析出钇钡铜氧薄膜表面各区域的腐蚀启动先后和刻蚀程度差异等重要信息,为钇钡铜氧及其它材料的激光化学刻蚀特性的实时监测提供了一种新的技术手段.     

教书育人 重在培养学生的能力

本文阐述了教书育人，重在培养学生能力的重要性，介绍了在数学课程的教学中培养学生的各种能力的具体做法。     

Flow Structures Around Micro-bubbles During Subcooled Nucleate Boiling

The flow structures were investigated around micro bubbles on extremely thin wires during subcooled nucleate boiling.Jet flows emanating from the bubbles were observed visually with the fluid field measurement using high-speed photography and a PIV system.The jet flows induced a strong pumping effect around a bubble.The multi-jet structure was further observed experimentally, indicating the evolution of flow structure around micro bubbles.Numerical simulations explore that the jet flows were induced by a strong Marangoni effect due to high temperature gradients near the wire.The bubble interface with multi-jet structure has abnormal temperature distribution such that the coolest parts were observed at two sides of a bubble extending into the subcooled bulk liquid rather than at the top.Evaporation and condensation on the bubble interface play important roles not only in controlling the intensity of the jet flow,but also in bringing out the multi-jet structure.     

高温超导窄带广义切比雪夫函数滤波器

提出了一种用于高温超导滤波器制作的新结构窄带广义切比雪夫函数高、低通滤波器级联方式.该方式利用高温超导低插损特性,可以有效地降低极陡峭广义切比雪夫函数低通、高通滤波器的带边频滚降.依靠高、低通滤波器级联方式构建新形式的窄带极陡峭低插损高温超导滤波器,并与已有高温超导滤波器进行了比较分析.     

微波促进下6,7-二氢-5H-环戊二烯并[4,5]噻吩并[2,3-d]嘧啶-4-胺的简便合成（英文）

微波辐射条件下,以乙醇作溶剂,环戊酮、丙二腈与单质硫反应得到2-氨基-5,6-二氢-4H-环戊二烯[b]噻吩-3-腈(1),1与N,N-二甲基甲酰胺二甲基缩醛在微波辐射条件下反应得到N-(3-氰基-5,6-二氢-4H-环戊二烯[b]-硫基-2-基)-N,N-二甲基亚甲基酰胺(2),进一步在微波辐射条件下由N-(3-氰基-5,6-二氢-4H-环戊二烯[b]-硫基-2-基)-N,N-二甲基亚甲基酰胺(2)与取代芳香胺反应制得目标化合物.合成的25个目标化合物通过熔点测定和核磁共振氢谱分析、红外光谱、高分辨质谱对其结构进行确证.     

微波促进的Dimroth重排反应合成吡啶并[2,3-d]嘧啶-4-胺衍生物（英文）

研究了N-(3,5-二氯苯基)吡啶并[2,3-d]嘧啶-4-胺的合成新方法.在微波辐射条件下,以2-氨基-3-氰基吡啶为原料,依次通过缩合、环化和Dimroth重排两步反应,得到目标产物N-(3,5-二氯苯基)吡啶并[2,3-d]嘧啶-4-胺,总收率90%.并应用该方法,合成了20个吡啶并[2,3-d]嘧啶-4-胺类化合物.同时,比较了微波辐射和传统油浴加热条件下的反应结果.结果表明,微波辐射条件下,反应时间短,产率高.此方法有望成为一种高效、温和、对环境友好的合成吡啶并[2,3-d]嘧啶-4-胺的方法.