富水岩溶地层三车道公路隧道二次衬砌受荷特征研究

施工质量差造成二衬背后排水系统效率低下,遇突发性降水则会造成二衬背后水头高度增加,二衬实际受荷为初支、二衬接触压力与二衬背后外水压力。以某三车道公路隧道为依托,对多个断面初支、二衬接触压力进行现场测试并回归分析,运用荷载结构模型计算二衬在实测接触压力、外水压力共同作用下的内力分布规律,并与实测数据进行对比,结果如下:初支、二衬间接触压力分布较为均匀,量值小于设计荷载;二衬背后水头高度增加将显著增大墙角、仰拱处弯矩,水头高度大于6 m时,弯矩增大更为明显;二衬各测点处轴力随背后水头高度增加整体呈增大趋势,水头大于6 m时,二衬下半断面轴力变化速度明显增大;大于8 m时,上半断面轴力变化速度明显增大。采用换算后接触压力、外水压力计算得到二衬内力与实际二衬内力量值、分布规律基本一致。

蠕变作用下埋深对结构受荷特征影响分析--以广佛环线东环隧道工程为例

为研究在围岩蠕变作用下不同埋深软岩盾构隧道管片结构的受荷特性,以广佛环线东环隧道工程为背景,利用FLAC3D(fast lagrangian analysis of continua in 3 dimensions)有限差分软件建立了数值分析模型,采用改进的黏弹塑性蠕变本构(burgers-creep viscoplastic model, CVISC),分析了埋深对管片的位移、内力及与围岩的接触压力影响。结果表明:隧道初期开挖之后,顶部围岩沉降,底部发生隆起,考虑围岩蠕变效应后,管片衬砌发生整体沉降,隧道埋深越大,管片体整体沉降越发显著;随隧道埋深的增大,弯矩、轴力与接触压力均逐渐增大。围岩未考虑加速蠕变下,蠕变过程中管片衬砌的内力和接触压力的变化规律基本相同,有衰减蠕变和稳定蠕变两个阶段。

基于荷特征的概念车仿生设计研究

目的荷在开花与结果的生长过程中,呈现出不同的特征,挖掘各个生长阶段的特征,使其应用在概念车创新性设计中,为概念车仿生设计开辟新思维。方法利用仿生设计原理,从形态仿生、功能仿生、结构仿生、色彩仿生四方面,对荷与荷之关联的荷花、荷叶、藕进行形态、功能、结构、色彩的特征分析,让荷花、荷叶、藕的特征与概念车各部位的设计进行对比、分析与糅合。结论对荷的仿生特征进行分析,让其合理运用于概念车的形态、功能、结构、色彩创新设计中,提出了以荷特征为基础的概念车仿生设计方法,为创造出更具有自然特征的概念车提供了途径,为完善概念车仿生设计方法提供了思路。

硅纳米晶粒基MOSFET存储器的荷电特征研究

本文研究了硅纳米晶粒MOSFET存储器的荷电特征 .器件阈值电压偏移达 1 8V以上 ,并随着沟道宽度的变窄而增加 ,而与沟道长度基本无关 .同时 ,阈值涨落也随宽度的变窄而增大 .在 2 0～ 30 0K测量温度范围内 ,器件阈值偏移和电荷的存储特性几乎不随温度变化 ,说明荷电过程主要由直接隧穿决定 .进一步 ,在最窄沟道器件中观察到单电荷的荷电过程 .

考虑源–荷随机–模糊特征的配电网潮流不确定性量化方法

分布式可再生能源发电在配电网中的比例逐年提高,其不确定性给配电网的安全运行带来了挑战,量化研究源–荷不确定性对配电网潮流的影响具有重要意义。计及源–荷的随机–模糊特征,该文建立随机源–荷模糊参数模型,提出考虑源–荷随机–模糊特征的配电网潮流不确定性量化方法,包括不确定性表征和灵敏度分析两个阶段。在不确定性表征阶段,提出基于多项式混沌克里金方法(polynomial-chaosbased Kriging,PCK)的配电网随机–模糊潮流高效计算方法。在灵敏度分析阶段,提出基于隶属函数的全局灵敏度分析(global sensitivity analysis,GSA)方法,用于定量评估随机源–荷模糊参数对配电网潮流的影响,准确辨识关键随机源–荷模糊参数。将所提方法应用于含分布式可再生能源的33节点和123节点配电网系统进行仿真计算,验证了所提方法的有效性。

“双碳”目标下新型电力系统典型特征与发展挑战综述

构建新型电力系统是实现“碳达峰、碳中和”目标的重要举措。为了更好地开展新型电力系统的规划发展研究工作,从多个角度阐述了对新型电力系统的认识,提出了新型电力系统的典型特征;并进一步从管理与体制机制、经济性、技术性3个方面,剖析了当前构建新型电力系统面临的主要挑战。

基于改进加权距离的建成区布线及供电范围调整

针对建成区源荷空间发展与配电网供电范围调整及其建设改造之间的复杂耦合关系,提出一种基于改进加权距离的建成区布线及供电范围调整方法。首先,结合建成区与新建区自动布线的技术差异性,建立建成区配电网供电范围调整及其自动布线一体化优化框架;其次,提出考虑新增源荷归属动态调整的新建线路待选条数区间计算方法;然后,综合考虑负载率越限改进效果和源荷距离特征,提出基于改进加权距离的新建线路供电范围划分和基于混合整数线性优化的网架布局方法;最后,通过所提实例验证模型和方法的经济性与实用性。

深埋软岩盾构隧道围岩压力控制方法研究

以广佛环线东环隧道工程为背景,从盾构隧道动态施工全过程出发,参考考虑开挖面空间效应的二阶段分析方法,拓展盾构隧道施工全过程的两阶段分析方法,以此分别建立盾构隧道施工第一阶段和第二阶段分析模型,研究围岩蠕变过程中围岩应力释放率、填充层厚度、填充层弹性模量对大埋深软岩盾构隧道围岩和支护结构相互作用规律的影响。结果表明:(1)施工过程中可从两方面控制围岩压力,分别为第一阶段中围岩的应力(位移)释放率及第二阶段中管片和填充层的联合支护效果;(2)第一阶段,超挖量、盾壳长度及填充层滞后距离越大,围岩传递到管片衬砌上的荷载越小;(3)壁后填充层在管片衬砌与其的联合支护体系中能起到缓冲作用,使围岩传递到管片衬砌上的荷载更均匀;(4)壁后填充层的弹性模量存在临界值,其值在50~200 MPa范围内,当壁后填充层的弹性模量远大于此临界值时,能分担较多围岩压力,当其弹性模量小于临界值时,围岩能释放一定的围岩应力,以此减小管片衬砌所受围岩压力;(5)第一阶段应力释放率对管片衬砌变形和内力的影响程度在围岩的蠕变作用下有所减小,但填充层厚度及其弹性模量对管片结构的作用规律几乎不受围岩蠕变的影响。

Effect of induction unloading on weakening of rock mechanics properties

The effects of induction unloading such as drilling, blasting, lancing and water-infusion softening on weakening of rock mechanics properties were investigated. Three stress paths were chosen as test schemes corresponding to the triaxial compressive test, pre-peak and post-peak unloading the confining pressure tests. The results show that compression deformation is the main cause of rock failure under loading condition. However, the strong dilatation leads to the rock failure along unloading direction. Rock failure happens even under little axial stress with confining pressure unloading. Poisson ratio increases with the decrease of confining pressure during the process of unloading. Elastic modulus increases slowly along with the decline of confining pressure, but decreases rapidly when unloaded to yielding strength. It shows that the weakening rate of rock intensity tends to be faster with easily failure under the unloading condition.

铁锰复合氧化物混凝除微污染效能与机理

研究了铁锰复合氧化物(FeMnO)的界面特性、荷电特征及结构形貌,考察了FeMnO混凝效能,探讨了除污染机理.结果表明,FeMnO以δ-MnO2和氢氧化铁为主要成分,含有丰富的表面羟基,比表面积达146.22m2/g;在纯水体系中的零电荷点pH值约为8.0;FeMnO为尺寸不均的准球型微小颗粒,相互黏附成网状结构.FeMnO混凝使滤后浊度、TOC和UV254的去除率分别达到99.99%、42.25%和68.91%.其混凝除浊、除有机物的机制为吸附架桥、电性中和及网捕卷扫等共同作用的结果.

地铁衬砌结构实施可靠度设计的探讨

介绍了浅埋地铁整体式衬砌采用可靠度设计的背景和目前可供引用的成果,建议按不同结构类型分阶段实施,要做的工作主要是补充和完善各种荷载的统计特征。

硅量子点中电子的荷电动力学特征

利用频率依赖电容谱的测量 ,对于SiO2 /硅量子点 /SiO2 /硅衬底隧穿电容中硅量子点的荷电特征进行了研究 .由于量子点的极小尺寸和良好的均匀性 ,室温下在强反型区成功地观察到了与单电子隧穿相关的两个电容和电导共振峰 ,它们分别对应于硅衬底导带上的电子与量子点中第一与第二个基态之间直接隧穿过程 .实验数据分析给出了量子点中的库仑荷电能 ,并进行了讨论 .

绿色低碳能源转型背景下的新型乡村能源体系形态特征与关键技术

随着“双碳”目标和乡村振兴战略的推进,乡村能源体系正面临着绿色低碳转型的新局面。由于多元源荷规模化接入配电网和用户侧柔性调节能力增强,乡村能源体系的形态特征发生了巨大改变,对规划配置、运行管控等提出了新的挑战。针对绿色低碳能源转型背景下的政策要求和发展目标,分析了新型乡村能源体系源侧、荷侧新形态,明确了当前乡村能源体系面临的主要问题,提出了新型乡村能源体系发展需要突破的关键技术。进一步对新型乡村能源体系相关问题的解决思路进行了探讨。

一种100V分离栅沟槽MOSFET的优化设计

把多个侧壁阶梯氧化层应用于分离栅沟槽MOSFET(Split-Gate Trench MOSFET,SGT结构),并把改进的结构称为多阶梯侧壁氧化层分离栅沟槽MOSFET(Multi-Step Sidewall Oxides Split-Gate Trench MOSFET,MSO结构),之后介绍了MSO结构的器件结构和制备工艺,重点借助TCAD仿真软件对MSO结构的外延层掺杂浓度、顶部侧氧厚度与底部侧氧厚度进行优化,最终仿真得到击穿电压为126V,特征导通电阻为30.76mΩ·mm^2和特征栅漏电荷为0.351nC·mm^(-2)的MSO结构.在近似相等的击穿电压下,与传统SGT结构相比,MSO结构的特征导通电阻及特征栅漏电荷均有所降低,这两项参数综合反映器件的优值(FOM=Qgd,sp×RonA)降低了39.6%.

Charge Properties and Clay Mineral Composition of Tianbao Mountains Soils

The clay mineral association, oxides of clay fraction and surface charge properties of 7 soils, which are developed from granite, located at different altitudes of the Tianbao Mountains were studied. Results indicate that with the increase in altitude, 1) the weathering process and desilicification of soil clay minerals became weaker, whereas the leaching depotassication and the formation process of hydroxy-aluminum interlayer got stronger; 2) the contents of amorphous and complex aluminum and iron, and the activity of aluminum and iron oxides for soil clay fraction increased; and 3) the amount of variable negative charge, anion exchange capacity and the values of PZC and PZNC also increased. The activity of aluminum and iron oxides, the accumulation of aluminum, and surface charge characteristics and their relation to clay oxides of the vertical zone soils were observed and recorded.

Effects of axial cyclic loading at constant confining pressures on deformational characteristics of anisotropic argillite

Triaxial cyclic loading tests have been performed to assess the influence of plastic deformation on inelastic deformational properties of anisotropic argillite with bedding planes which is regarded as a kind of transversely isotropic media.Considering argillite's anisotropy and inelastic deformational properties,theoretical formulae for calculating oriented elastic parameters were deduced by the unloading curves,which can be better fitted for the description of its elasticity than loading curves.Test results indicate that with the growth of accumulated plastic,strain,the apparent elastic modulus of argillite decreases in a form of exponential decay function,whereas the apparent Poisson ratio increase in a form of power equation.A ratio of unloading recoverable strain to the total strain increment occurred during a loading cycle is defined to illustrate the characteristic relations between anisotropic coupled elasto-plastic deformation and plastic strain.It is significant to observe that high stress level and plastic history have an inhibiting effect on argillite anisotropy.

Variation characteristics of aquifer parameters induced by groundwater source heat pump operation under variable flow

The variation characteristics of aquifer parameters,induced by groundwater source heat pump(GWSHP) operation under variable flow,were theoretically analyzed through a case study,in which the characteristics of building air conditioning load were considered.The results,compared with the constant flow operation,indicate that the influence on the variations of porosity,hydraulic conductivity and confined water head is decreased by 48%,51% and 71%,respectively,under variable flow operation.The security of variable flow operation is superior to that of constant flow.It is also concluded that the climate region and function of the buildings are primary factors which affect the suitability of variable flow operation in GWSHP.

A novel quantificational assessment method of frothers effect on bubble characteristics

A new visual method for quantitative measurement of frothers effect and flotation efficiency was presented. A self-designed electrolytic cell was chosen as the reaction environment with sodium chloride (NaCl) as the electrolyte. Constant current, supplied by a self-designed power supplier and fixed cathode and anode equipment, guaranteed the constant bubble volume per unit time. Even aperture of the cathode material guaranteed the original bubbles size to be uniform. Bubble generating equipment was connected with a microscopical camera. Statistic data collected by high speed charge-coupled device (CCD) and processed by software Sigmascan and Matlab could reflect bubble characteristics. The efficiency of dipropylene glycol monomethyl ether (DPM) and tripropylene glycol n-butyl ethel (TPnB) were measured at the same condition, and 2×10-4 mol/L and 5×10-2 mol/L were found to be the inflexions of bubble size changes.

Calculation of Ground Vertical Displacements,Tilts and Their Distribution Characteristics around an Irregular Load

Based on the load model of a uniform isotropic semi-infinite elastic medium,we deduced a calculation of vertical displacement and tilt and proposed a method of calculation of vertical displacements and tilts caused by irregular load on the ground or underground at a certain point with two-dimensional and three-dimensional shapes. We compared the difference between the simplified model and the irregular model. Finally,the vertical displacements near the irregular load and the distribution of horizontal tilt are presented.The results show that,compared with the point simplified model,the irregular load model has certain advantages for describing the near field. The establishment of a twodimensional irregular load model can help with the calculation of the modal vector superposition after load scattering. The three-dimensional irregular load model can redistribute load through different weights given to the scattered points after the load scattering,and then obtain displacement with the vector calculation method. The results of vector superposition calculation from the scattered irregular load both in two-dimensions and three-dimensions are all convergent obviously as grids become denser,and it is shown that the calculation method is correct and feasible.

THE CORRELATIONS OF CLINICOPATHOLOGIC FEATURES, HORMONE RECEPTOR LEVEL WITH THE PROGNOSIS OF BREAST CANCER: REPORT OF 308 CASES IN ELDERLY WOMEN

Objective. This study analyses the clincopathologic features and hormone receptor level of breast cancer in aged patients(≥60 years) and explores the related factors of the prognosis.Methnds. For all patients,the clinical data and pathologic data were reviewed retrospectively. Followup data were available. Of the 308 cases,tumor specimens in 130 patients were subjected to hormone receptor analysis by a dextran-coated charcoal technique.Results’ Of the 308 cases, 82 cases were in stage I, 147 cases in stage II, 66 cases in stage III,and 13 cases in stage IV. Metastatic rate (axillary lymph nedes) was 35. 7%. The overall postoperative 5 and 10-year survival rates were 70. 8 % and 50. 5 %,respectively. Estrogen receptor and progesterone receptor positive rates were 66. 9 % and 40.0%,respectively. The survival rate was decreased with the increasing grade of TNM(P<0.01). The mortality rate of the breast cancer was related to the clinical stage and the hormone receptor level (P<0. 05 ).Conclusbos. There was a relatively gdri prognosis in this series. The size of tumor, number of metastatic nedes and hormone receptor level were related to the prognosis.