盾构隧道纵向结构变形模式及理论模型#br#

盾构隧道在长期运营中极易发生不均匀沉降及纵向结构变形，因而有必要建立隧道纵向结构计算模型，分析隧道纵向变形及内力特征。首先探讨隧道纵向变形模式，将隧道变形归纳为两种模式：①弯曲变形模式；②错台变形模式。其次针对现有纵向结构计算模型进行总结并分析其优缺点，根据模型的简化过程将现有模型归纳为两类：①纵向管片环-接头模型；②纵向等效连续化模型。针对隧道实际剪切错台变形的特点，重点介绍一种基于铁木辛柯梁理论的隧道纵向连续化模型，并通过实例分析其优越性。     

Coupling analysis and optimization of commercial vehicles cab comfort with multi-platform integrated calculation

Journal of Mechanical Science and Technology - This article introduces a rigid-flexible coupling calculation model based on a multi-platform integrated method to analyze and optimize the cab...     

吉林铜钴镍多金属硫化矿的生物浸出试验研究

吉林某铜钴镍多金属硫化矿品位低,成分复杂,对其开展了生物摇瓶浸出与柱浸试验研究,结果表明:浸出温度对铜钴镍浸出率的影响显著,生物摇瓶浸出的适宜条件为矿浆浓度15%,初始pH值1.5,浸出温度30℃,不添加Fe~(2+);酸浸预处理7d后进行生物柱浸试验,矿石粒度为-10 mm,接菌浸出60 d后,铜、钴、镍的浸出率分别为7.32%、27.47%和27.08%,与矿石粒度-20 mm无菌浸出的条件相比,钴镍浸出率提高了近8个百分点,说明细粒有菌条件有利于金属的浸出;分析浸矿菌群组成,优势菌主要为嗜酸硫杆菌属(Acidithiobacillus)和钩端螺旋菌属(Leptospirillum)。     

基于MIKE URBAN的西安市中心城区雨洪过程模拟

城市排水管网的分布与建设是城市基础设施建设的重要组成部分,城市的排水能力关系到城市服务功能的正常运转。通过城市雨洪过程的分析,可以评价城市洪涝灾害。以西安市中心城区为研究对象,利用MIKE URBAN构建排水管网模型,根据模拟结果对研究区管网排水能力进行评估,分析易涝成因。结果表明:MIKE URBAN能够较好地模拟城市管网水位、流量变化及易涝点的分布情况。根据西安市暴雨强度公式,设计不同重现期(1、2、3、5a)的降雨过程,在1a降雨过程下,研究区90%以上管道处于满流状态,60%以上的检查井发生溢流,满流管段数和溢流井个数会随着降雨频率的增加而增加,但增幅相对减少;管道设计标准普遍偏低、下垫面不透水率增大、地形等因素是导致地面积水的主要原因。研究成果可为城市内涝防治及海绵城市建设提供理论基础和技术支撑。     

Vacuum-drain consolidation induced pressure distribution and ground deformation

The method of using a surface or subsurface soil layer as an air-sealing layer to carry out vacuum consolidation is referred to as the vacuum-drain method. A method of determining the vacuum-drain consolidation induced vacuum pressure distribution in the ground has been proposed based on unit cell finite element analysis results. With the calculated vacuum pressure distribution, a method for calculating the settlement–time curve and the lateral displacement profile at the edge of the vacuum consolidation area has been established. Finally, the proposed methods were applied to a project using the vacuum-drain method at Tokyo Bay in Japan. Comparing the calculated results with the measured field values indicates that the methods can be a useful tool for designing vacuum consolidation project.     

适用于中国超宽带标准的0.18μm-CMOS单边带混频器设计

基于0.18 μm-CMOS工艺设计了一款适用于中国超宽带(UWB)标准的单边带(SSB)混频器.对电流换向型混频器进行分析,提出折叠PMOS跨导级结构使线性度和转换增益得以同时提升,并应用并联峰化技术扩展电路带宽,满足了系统超宽带、高线性度和增益适中的要求.结果表明,在6 GHz～9 GHz范围内,转换增益大于-2 dB且增益平坦,镜像抑制约为90dB,IP-1dB大于0 dBm,ⅡP3大于10 dBm.电路核心面积0.35mm×0.65 mm,工作电压为1.8 V,直流电流10.6 mA.     

环锭纺纱企业减少用工与提升产品档次途径的探析

针对纺纱企业当前面临的严峻形势,分析走出困境的途径。文章结合春江轻纺集团面对严峻形势采取的必要措施及取得的成绩,认为通过技术创新与管理创新、减少劳动用工与产品结构调整、不断开发市场需求的产品等方面入手,降低工费成本、提升产品附加值,能使企业走出困境,走上持续发展之路。     

An improved charge-averaging charge-pump scheme

An improved charge-averaging charge-pump scheme is described in the paper. The circuit mainly includes four pairs of switches and four sampling capacitors. Two operation modes (normal/charge-averaging) are achieved by switching on/off. SpectreVerilog simulation results show the proposed scheme can strongly reduce the energy of spurs, and could be applied to high performance frequency synthesizers.     

电力变压器改造方案与经济分析

通过对变压器各种改造方案的分析比较得出 ,不同状态时的最佳改造方案。     

Comparison in Undrained Shear Strength between Undisturbed and Remolded Ariake Clays

Triaxial consolidation undrained shear tests are performed on both undisturbed and remolded Ariake clays to investigate the undrained shear strength behavior. When the applied confining stress is larger than the triaxial consolidation yield stress, the strength envelopes expressed in the plot of undrained shear strength versus confining stress of both the undisturbed and the remolded Ariake clays are straight lines through the origin. The strength envelope of the remolded Ariake clays lies above that of the undisturbed Ariake clays when the applied confining stress is larger than the consolidation yield stress. This difference is caused by the difference in water content between undisturbed and remolded states. When the data obtained from triaxial consolidation undrained shear tests of both the undisturbed and the remolded Ariake clays are plotted in the plot of undrained shear strength versus water content, it is found that the undrained shear strength decreases uniquely with the increase in water content.