基于CA交通流模型的车辆停车次数及停车率的仿真研究

运用CA交通流仿真模型对路段上车辆的停车状况进行仿真研究,仿真了路段上车辆的停车次数及停车率与密度之间的关系。结果表明,用CA模型可以较好地模拟路段上车辆的停车情况,能较好地仿真出路段上车辆的停车次数及停车率与密度之间变化的定量关系。这一结果为根据交通流密度采取相应的交通管理措施提供了理论依据。     

钛碳化硅陶瓷制备方法综述

简述了钛碳化硅Ti3SiC2陶瓷的结构与性能,综述了国内外Ti3SiC2陶瓷的制备方法,并对Ti3SiC2陶瓷的应用前景进行了展望。     

“数字规划”的支撑技术与实践

为了迎接信息社会的挑战,必须实现“数字规划”,才能充分发挥城市规划的龙头作用,合理利用城市资源,有效指导建设、管理城市、实现可持续发展。探讨了“数字规划”建设的必要性、支撑技术、实践及体会。     

基于介质上电润湿原理的微液滴驱动芯片

为了实现对微尺度下流体的精确操控,提出一种基于介质上电润湿(e lectrow etting-on-d ie lectric,EW OD)的新型微液滴驱动芯片。研究了介质上电润湿原理及“三明治”结构驱动机制,并利用流体软件(CFD-ACE )数值模拟液滴在“三明治”结构中的驱动情况;分析了“三明治”结构液滴驱动芯片的工艺,并提出在重掺杂多晶硅电极阵列表面上热氧二氧化硅介质层来制备低驱动电压及高可靠性的新结构驱动芯片;在空气环境下,通过施加45V驱动电压成功实现了对去离子离散液滴的操作和控制。     

基于均匀相位采样提高阻抗谱测量精度的研究

周期性信号采样中,等效采样利用较低采样频率的A/D转换实现高频周期信号的采集,一定程度上弥补欠采样测量精度低的缺陷。本文提出一种基于等效采样思想的均匀相位采样的阻抗谱测量方法,有效地提高高频测量中阻抗谱测量精度与稳定性。在利用单片机共时钟基准的DAC与ADC模块,在完成激励信号产生、输入输出信号同步采集的基础上,合理设计激励信号频率、采集频率与信号重构方法,实现高频信号单周期内均匀相位分布的等效高频采样,同时为克服常规A/D转换速度条件下难以准确实现高频阻抗谱测量的问题提供了新思路。从误差假设与拟合算法的角度,理论上分析证明了该方法降低误差的原因;并通过两种等效电路模型的阻抗谱测量对比实验,表明该方法在所设计的20k-100kHz高频段上,阻抗测量精度与稳定性得到了显著的提高。     

一种可变直径软体机器人的设计

为了解决刚性机械手安全性低、适应性差的问题,设计一款具有抓取功能的软体机器人。该软体机器人由三个呈圆周 120°分布的软体驱动器和一个夹具组成,夹具可以实现自动化改变直径以适应不同大小物体的抓取,经测算软体机器人可以抓取直径范围为 45mm~97mm 的物体。夹具和软体驱动器都采用3D打印制造,具有成本低、制造简单、易于大规模生产的优点。软体机器人采用气压驱动,当给驱动器充气时,三手指同时弯曲抓取物体,具有很好的稳定性。对于软体驱动器建立了相应的力学模型,得到了弯曲角度与输入气压的关系,并利用ABAQUS 有限元仿真软件对驱动器弯曲特性进行仿真。对比发现,理论建模和仿真分析在驱动器弯曲角度具有很高的吻合性。     

基于无人机航摄的地质踏勘及风险评估

工程选址前进行的地质踏勘是保证大型基建工程顺利开展的重要环节。为探索成本低、易于操作的地质踏勘技术,本文以中南地区某矿区为例,利用无人机搭载高分辨率相机以“高密度网格成像”模式获取影像,并实现研究区域的三维重建;通过点云模型生成数字高程模型后提取相关地质信息,进行潜在地质风险的初步判定。结果表明基于无人机航摄进行地质踏勘效率相较于人工有了显著提升,三维模型清晰,很好地反映了试验区域实际状态。“高密度网格成像”模式操作方便,三维模型、点云模型与数字高程模型的结合分析结果与现实吻合良好,研究结果可为地质踏勘工作提供新思路。     

Meta-analyses identify 13 loci associated with age at menopause and highlight DNA repair and immune pathways

To newly identify loci for age at natural menopause, we carried out a meta-analysis of 22 genome-wide association studies (GWAS) in 38,968 women of European descent, with replication in up to 14,435 women. In addition to four known loci, we identified 13 loci newly associated with age at natural menopause (at P < 5 × 10(-8)). Candidate genes located at these newly associated loci include genes implicated in DNA repair (EXO1, HELQ, UIMC1, FAM175A, FANCI, TLK1, POLG and PRIM1) and immune function (IL11, NLRP11 and PRRC2A (also known as BAT2)). Gene-set enrichment pathway analyses using the full GWAS data set identified exoDNase, NF-κB signaling and mitochondrial dysfunction as biological processes related to timing of menopause.     

Genome-wide association study identifies five loci associated with susceptibility to pancreatic cancer in Chinese populations

Pancreatic cancer has the lowest survival rate among human cancers, and there are no effective markers for its screening and early diagnosis. To identify genetic susceptibility markers for this cancer, we carried out a genome-wide association study on 981 individuals with pancreatic cancer (cases) and 1,991 cancer-free controls of Chinese descent using 666,141 autosomal SNPs. Promising associations were replicated in an additional 2,603 pancreatic cancer cases and 2,877 controls recruited from 25 hospitals in 16 provinces or cities in China. We identified five new susceptibility loci at chromosomes 21q21.3, 5p13.1, 21q22.3, 22q13.32 and 10q26.11 (P = 2.24 × 10(-13) to P = 4.18 × 10(-10)) in addition to 13q22.1 previously reported in populations of European ancestry. These results advance our understanding of the development of pancreatic cancer and highlight potential targets for the prevention or treatment of this cancer.     

Genome-wide association study identifies three new susceptibility loci for esophageal squamous-cell carcinoma in Chinese populations

Esophageal squamous-cell carcinoma (ESCC) is one of the most prevalent cancers worldwide and occurs at a relatively high frequency in China. To identify genetic susceptibility loci for ESCC, we conducted a genome-wide association study on 2,031 individuals with ESCC (cases) and 2,044 controls of Chinese descent using 666,141 autosomal SNPs. We evaluated promising associations in an additional 6,276 cases and 6,165 controls of Chinese descent from different areas of China. We identified seven susceptibility loci on chromosomes 5q11, 6p21, 10q23, 12q24 and 21q22 (ranging from P = 7.48 × 10(-12) to P = 2.44 × 10(-31)); among these loci, 5q11, 6p21 and 21q22 were newly identified. Three variants in high linkage disequilibrium on 12q24 confer their risks to ESCC in a gene-lifestyle interaction manner, with more pronounced risk enhancement seen in tobacco and alcohol users. Furthermore, the identified variants had a cumulative association with ESCC risk (P(trend) = 7.92 × 10(-56)). These findings highlight the involvement of multiple genetic loci and gene-environment interaction in the development of esophageal cancer.