聚变等离子体中的离散阿尔芬波本征模

聚变等离子体中存在负磁剪切的情况下,研究发现在α(α=-q2Rdβ/dr,q是安全因子,β是等离子体压力与磁压力之比,R和r分别代表托卡马克的大半径和小半径)引起的第二个势井里面存在αTAEs(α-induced Alfvén eigenmodes)。这些模式是一种很危险的本征模,容易被激发从而破坏聚变等离子体的稳定状态。对该本征模的研究,为该领域的研究提供了一些参考。     

一种基于频率补偿的GPS位同步方法

针对GPS接收机在跟踪过程中由频率误差引起的位同步概率下降问题,提出了一种基于频率补偿的GPS位同步方法.分析了环路中频率误差引起相干积分累加值衰减的机理,利用不同频率的复信号分别对相干积分结果进行补偿,计算出20个候选位置的值,最大值对应的位置即为数据边界位置.该方法有效减少了由频率误差导致的相干累加损耗,提高了位同步的概率.在弱信号情况下,使用非相干积分方法可进一步提高信号增益和位同步概率.与其他位同步方法相比,所提方法可容忍更大的频率误差,即使跟踪环路处于失锁状态也能准确实现位同步,且在频率误差小于25 Hz的情况下表现出更优的位同步性能.     

Association analyses identify multiple new lung cancer susceptibility loci and their interactions with smoking in the Chinese population

To find additional susceptibility loci for lung cancer, we tested promising associations from our previous genome-wide association study (GWAS) of lung cancer in the Chinese population in an extended validation sample size of 7,436 individuals with lung cancer (cases) and 7,483 controls. We found genome-wide significant (P < 5.0 × 10(-8)) evidence for three additional lung cancer susceptibility loci at 10p14 (rs1663689, close to GATA3, P = 2.84 × 10(-10)), 5q32 (rs2895680 in PPP2R2B-STK32A-DPYSL3, P = 6.60 × 10(-9)) and 20q13.2 (rs4809957 in CYP24A1, P = 1.20 × 10(-8)). We also found consistent associations for rs247008 at 5q31.1 (IL3-CSF2-P4HA2, P = 7.68 × 10(-8)) and rs9439519 at 1p36.32 (AJAP1-NPHP4, P = 3.65 × 10(-6)). Four of these loci showed evidence for interactions with smoking dose (P = 1.72 × 10(-10), P = 5.07 × 10(-3), P = 6.77 × 10(-3) and P = 4.49 × 10(-2) for rs2895680, rs4809957, rs247008 and rs9439519, respectively). These results advance our understanding of lung cancer susceptibility and highlight potential pathways that integrate genetic variants and smoking in the development of lung cancer.     

园林绿化工程苗木移植技术浅析

改善城市居住环境,在较短时间内改善城市景观,需要进行苗木移植.在苗木移植时不采用任何技术措施,种植后只按常规进行淋水管理,树木的成活率就很低.该文概述了苗木栽植原则,分析、归纳了园林建设过程中影响苗木移栽成活率的根系因素和环境因素,并提出了提高园林苗木栽植成活率的对策:(1)做好土壤处理、场地平整及把好苗木质量关等前期准备工作;(2)苗木适时假植;(3)定植前适当修剪与科学定植;(4)分级管养.上述移栽技术经过多年的工程实践证明,能保证树种的成活率在80%以上.     

Critical Systems Thinking on the Inefficiency in Post-Earthquake Relief: A Practice in Longmen Shan Fault Area

The Longmen Shan Fault area is one of the most active seismic zones in the world, has a relatively dense population and a low economic development level. Therefore, the provision of effective post-earthquake relief is very important for saving lives and restricting financial losses. However, providing urgent relief is a complex problem that requires efficient coordination between the organizations, and departments involved, and the specific environments, for the supply of urgent materials, energy and information. In practice, although there are sufficient relief supplies, because of the lack of systemic thinking, relief activities are often chaotic leading to inefficiencies and even increases in the damage and loss of life. In this study, a critical systems thinking approach is used to reflect on the system contexts, boundaries, structures and functions of the emergency relief systems. Using systems modeling we constructed simulations for different relief plans and their consequences, and a work shop of metasynthetic engineering was constructed to integrate the different views, knowledge and contexts. At the practical stage, after the model’s validity was verified from the 2008 Wenchuan earthquake data, based on the 2013 Lushan earthquake simulation results, some recommendations are made to improve future post-disaster relief operations. Finally, the significance of critical systems thinking is demonstrated to ensure effective and efficient of post-earthquake relief. Some limitations and future research also have been presented in conclusion.     

从王昌龄边塞诗看其对边塞战争的态度

王昌龄是唐代著名的边塞诗人,他对当时边塞战争的认识经历了一个不断深化的过程,从他的边塞诗中,我们可以清楚地看到其对当时边塞战争的态度。青年时代漫游边关,慷慨激昂,热情讴歌、积极支持保卫边关的战争;深入了解边塞和戍边士卒的现实情况后,他开始厌倦没完没了的开边战争;随着人生阅历的增加,他对边塞战争给人民带来的苦难有了更深的认识,到晚年他更是明确反对穷兵黩武的开边、扩边战争。     

周期性微结构的纳秒激光四光束干涉烧蚀研究

多光束干涉是一种快速制备大面积周期性微纳结构的简易方法.本文基于四光束干涉烧蚀技术,利用纳秒激光在硫化锌衬底上无掩模烧蚀制备大面积的结构阵列;并详细研究了结构形貌随曝光时间的演化规律;利用四光束干涉理论,重点研究了四光束干涉时角度误差引起的相移对于结构类型的影响;结合我们近几年的研究工作,讨论多光束干涉烧蚀面临的挑战及展望.     

Joint analysis of recurrent event data with a dependent terminal event

Recurrent event data frequently occur in many longitudinal studies, and the observation on recurrent events could be stopped by a terminal event such as death. This paper considers joint modeling and analysis of recurrent event and terminal event data through a common subject-specific frailty, in which the proportional intensity model is used for modeling the recurrent event process and the additive hazards model is used for modeling the terminal event time. Estimating equation approaches are developed for parameter estimation and asymptotic properties of the resulting estimators are established. In addition, some procedures are presented for model checking. The finite sample behavior of the proposed estimators is evaluated through simulation studies, and an application to a heart failure study is provided.     

对数线性模型的选择方法及其应用

为构造最佳对数线性模型,通过λ系数构造λ相关系数矩阵,将其作为对数线性模型中交互项选择的方法,并用于分析肺癌治疗数据。结果表明,选出的交互项可以构造最佳的模型对数据进行准确的分析,因此在应用对数线性模型分析前,先用相关系数矩阵进行探索性研究分析是很有必要的。     

Synthesis,characterization, and theoretical study of N,S-codoped nano-TiO<Subscript>2</Subscript> with photocatalytic activities

Nitrogen and sulfur doped titanium dioxide photocatalysts were prepared by the sol-gel method. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and UV-visible diffuse reflectance spectra (DRS). Photocatalytic activities of the samples were investigated on the degradation of methyl orange (MO). The effect of the dopants on the electronic structure of TiO₂ was studied by the first-principles calculations based on the density functional theory (DFT). The orbital hybridization resulted in energy gap narrowing and electronic delocalization in the crystal of doped TiO₂. Mobile electrons of varied energetic states could offer enhanced electron transfer, together with optical absorption improvement. The results show that the doping elements of N and S play a cooperative role in the modification of electronic structure, which enhances the photocatalytic performance. The experimentally observed absorption edges of N-doped TiO₂, S-doped TiO₂, and N, S-codoped TiO₂ are 420, 413, and 429 nm, respectively, which can be explained by the theoretical calculation results.