新型M-THGEM结构探测器的蒙特卡罗模拟研究

新型多层厚型气体电子倍增器（Multi-layers THick Gas Electron Multiplier，M-THGEM）和传统THGEM （厚型气体电子倍增器）相比，具有连续的雪崩区，能够在低气压和低电压下都有较高增益，结构更紧凑，易于大面积制作等优势。对M-THGEM探测器的工作原理及性能进行了模拟研究，首先通过有限元（ANSYS）软件对二层与三层结构的M-THGEM进行了建模，对电场和电势分布分别进行了模拟计算；再利用Garfield++程序包对M-THGEM探测器在不同低气压和不同工作电压下的增益、感生信号、正离子反馈率等性能进行了研究。模拟结果表明，三层结构M-THGEM在低气压（200 Torr）、纯He气体条件下，能够获得较稳定的增益（105），输出信号的宽度在12 ns左右；同时，为降低正离子反馈率，本工作提出并研究了一种非对称的电压施加方式，结果表明，这种施加方式能有效降低正离子的反馈率。Compared to THGEM (Thick Gas Electron Multiplier), the novel Multilayer Thick Gaseous Electron Multiplier (M-THGEM) has many advantages, such as continuous avalanche zone, more compact structure, high gain at low pressure and low operating voltage, and easy to make large-area production. In the presented work, two types of the M-THGEM detector (two or three layers) were modeled, and their main principle and performances were also studied by simulation. Two types of the detector were molded and simulated by using the finite element software (ANSYS), and the electric field distribution and nodes information lists were figured out. The effective gain and induced signal from M-THGEM detector at different gas pressures and operating voltages were studied with the Garfield++ package. The simulation results shown that M-THGEM can obtain a stable higher gain around 105 in an environment where has a low pressure even in 200 Torr and within a pure inertia gas such as He. At this condition, the width of the induced signal from the three-layers structure is around 120 ns. Additionally, an asymmetric way of the applied voltage was studied and aim to reduce the efficiency of ion feedback, and our results show that this method is effective.     

云南蕊木茎中的抗炎吲哚生物碱

应用多种色谱和波谱学方法,从云南蕊木(Kopsia officinalis)茎中分离鉴定了27个单萜吲哚生物碱,包括7个新化合物kopsiofficines A^G和20个已知化合物.此外,建立脂多糖(LPS)诱导的小鼠巨噬细胞RAW 264.7炎症模型,通过测定IL-1β,PGE2和TNF-α炎症因子释放评价生物碱的抗炎活性.结果表明,kopsiofficines A(1),kopsiofficines B(2),kopsiofficines D(4),kopsiofficines F(6),kopsiofficines G(7),12-methoxykopsine(11),kopsinoline(15),(-)-N-methoxycarbonyl-11,12-methylenedioxykopsinaline(16),kopsinine(18)和kopsinic acid(20)表现出显著的抗炎活性,与阳性对照(地塞米松)基本相当.研究发现C-5位丙酮基取代的单萜吲哚生物碱的抗炎活性明显强于原型生物碱,推测丙酮基可能是抗炎活性的药效促进基团,研究结果为进一步的结构修饰和药理学研究提供了线索.     

基于界面超分子主客体识别作用的仿生自修复水润滑研究

通过界面超分子主客体识别作用，成功地将端金刚烷基聚甲基丙烯酸3-磺酸丙酯钾分子组装到接枝环糊精分子的硅片表面；通过原子力显微镜，表面元素分析，膜厚变化，表面润湿特性等手段证实该聚合物的成功组装. 通过摩擦试验证实:表面组装端金刚烷基聚甲基丙烯酸3-磺酸丙酯钾分子后，在轻载条件下，具有极低的摩擦系数，呈现流体润滑状态；而在高载荷条件下，可能是由于表面组装的聚合物被部分剪切掉而呈现较高的摩擦系数. 更重要的是，基于这种超分子作用间的可逆的非共价相互作用，该表面可呈现一种自修复的润滑效果，即在部分端金刚烷基聚甲基丙烯酸3-磺酸丙酯钾分子被剪切掉后，在客体大分子稀溶液中自组装后可再次获得低摩擦系数状态。      

基于瓶颈模型的交通拥堵收费与补贴模式研究

为了既保证交通拥堵收费的效率又降低个人出行者的出行成本,使得社会和个人利益能有效统一并提高公众对拥堵收费的接受度,基于双通道瓶颈模型设立了拥堵收费与补贴相混合的模式,将收费路段的收费收入全部或部分补贴到免费路段上.进而我们对该模式的参数和效果进行算例分析,发现该模式可以有效地减缓交通拥堵.同时模式与一般动态单通道收费相比在社会成本缩减方面仅有微小劣势,但却使得小汽车出行者的成本大幅缩小,公平度有显著提升.最后根据算例分析结果的比较,给出了方法最适用的情况     

一道题的巧证

题目已知25cosA 5sinB tanC=0,且sin2B-4cosA·tanC=0, 求证:tanC=25cosA. 分析仔细观察题目,发现它与一元二次方程的联系,即得证法.     

Laser-modified luminescence for optical data storage

The yearly growing quantities of dataflow create a desired requirement for advanced data storage methods. Luminescent materials, which possess adjustable parameters such as intensity, emission center, lifetime, polarization, etc., can be used to enable multi-dimensional optical data storage (ODS) with higher capacity, longer lifetime and lower energy consumption. Multiplexed storage based on luminescent materials can be easily manipulated by lasers, and has been considered as a feasible option to break through the limits of ODS density. Substantial progresses in laser-modified luminescence based ODS have been made during the past decade. In this review, we recapitulated recent advancements in laser-modified luminescence based ODS, focusing on the defect-related regulation, nucleation, dissociation, photoreduction, ablation, etc. We conclude by discussing the current challenges in laser-modified luminescence based ODS and proposing the perspectives for future development.     

基于粒子群优化的核匹配追踪目标识别

提出了一种基于粒子群优化的用于目标识别的核匹配追踪算法.该算法用粒子群优化算法在基函数字典中选择最优的基函数,大大降低了基匹配追踪算法的计算复杂度.通过与标准核匹配追踪算法及基于遗传算法的核匹配追踪算法对UCI数据集及纹理图像的识别试验表明,核匹配追踪算法优良的分类性能以及粒子群优化算法高效的全局搜索能力使新算法能有效识别目标数据.     

基于Biolog-Eco法对鄱阳湖不同湿地类型下土壤微生物功能多样性

湖泊湿地在水情驱动下,形成了以湖泊湿地为核心的多种湿地类型,本研究选择鄱阳湖4种湿地（草洲、泥滩、河口和湖泊湿地）土壤作为研究对象。采用Biolog-Eco微平板法分析不同湿地土壤微生物的功能代谢特征。结果发现,草洲湿地土壤微生物代谢活性最高,其次是河口,最后是泥滩和湖泊湿地,同时草洲还表现出最高的功能多样性。此外,4种湿地土壤均表现出对羧酸类、氨基酸类和胺类碳源具有较强的代谢能力,但不同湿地土壤中的微生物对碳源利用能力也表现出显著差异:相较于其他湿地类型下土壤微生物,草洲对氨基酸类碳源具有更高的利用能力;泥滩湿地更倾向于利用氨基酸类碳源;河口湿地对酚酸类和胺类碳源具有更高的利用能力;湖泊湿地更倾向于利用羧酸类碳源。相关性分析发现,湿地土壤微生物对碳源的利用能力主要受含水量和pH的负向影响,可溶性有机碳和微生物生物量碳的正向影响。