Full 2D Hydrodynamic Modelling of Rainfall-induced Flash Floods

Mountain catchments are prone to flash flooding due to heavy rainfall. Enhanced understanding of the generation and evolution processes of flash floods is essential for effective flood risk management. However, traditional distributed hydrological models based on kinematic and diffusion wave approximations ignore certain physical mechanisms of flash floods and thus bear excessive uncertainty. Here a hydrodynamic model is presented for flash floods based on the full two-dimensional shallow water equations incorporating rainfall and infiltration. Laboratory experiments of overland flows were modelled to illustrate the capability of the model. Then the model was applied to resolve two observed flash floods of distinct magnitudes in the Lengkou catchment in Shanxi Province, China. The present model is shown to be able to reproduce the flood flows fairly well compared to the observed data. The spatial distribution of rainfall is shown to be crucial for the modelling of flash floods. Sensitivity analyses of the model parameters reveal that the stage and discharge hydrographs are more sensitive to the Manning roughness and initial water content in the catchment than to the Green-Ampt head. Most notably, as the flash flood augments due to heavier rainfall, the modelling results agree with observed data better, which clearly characterizes the paramount role of rainfall in dictating the floods. From practical perspectives, the proposed model is more appropriate for modelling large flash floods.

Low-thrust trajectory optimization in a full ephemeris model

The low-thrust trajectory optimization with complicated constraints must be considered in practical engineering. In most literature, this problem is simplified into a two-body model in which the spacecraft is subject to the gravitational force at the center of mass and the spacecraft＇s own electric propulsion only, and the gravity assist （GA） is modeled as an instantaneous velocity increment. This paper presents a method to solve the fuel-optimal problem of low-thrust trajectory with complicated constraints in a full ephemeris model, which is closer to practical engineering conditions. First, it introduces various perturbations, including a third body＇s gravity, the nonspherical perturbation and the solar radiation pressure in a dynamic equation. Second, it builds two types of equivalent inner constraints to describe the GA. At the same time, the present paper applies a series of techniques, such as a homotopic approach, to enhance the possibility of convergence of the global optimal solution.

Full feature data model for spatial information network integration

In allusion to the difficulty of integrating data with different models in integrating spatial information, the characteristics of raster structure, vector structure and mixed model were analyzed, and a hierarchical vector-raster integrative full feature model was put forward by integrating the advantage of vector and raster model and using the object-oriented method. The data structures of the four basic features, i.e. point, line, surface and solid, were described. An application was analyzed and described, and the characteristics of this model were described. In this model, all objects in the real world are divided into and described as features with hierarchy, and all the data are organized in vector. This model can describe data based on feature, field, network and other models, and avoid the disadvantage of inability to integrate data based on different models and perform spatial analysis on them in spatial information integration.

Keladi candik(Alocasia longiloba Miq.) petiole extracts promote wound healing in a full thickness excision wound model in rats

Objective: To investigate the wound-healing effect of Alocasia longiloba(A. longiloba) petiole extract on wounds in rats.Methods: Twenty-two male Sprague-dawley rats were randomly assigned to receive 10% solcoseryl gel, phosphate buffer saline, 50% ethanol, 95% ethanol and hexane extracts of A. longiloba at 1.5%, 3% and 6% doses, respectively. A full thicknesses wound(6 mm) was created on the dorsal of the rat; and all rats were applied with the extract solutions, 10% solcoseryl gel and phosphate buffer saline once a day topically until day 12. The wound was photographed on day 1, 6 and 12, and the percentage of wound contraction was calculated. On day 12, rats were sacrificed and histological examination of granulation tissue was carried out using haematoxylin & eosin and Masson's Trichrome stain to determine the wound healing effect.Results: In this study, 6% of 50% and 95% ethanol extracts of A. longiloba showed 82.50% and 82.32% wound contraction, respectively, and were comparable with 10% solcoseryl gel(82.30%). Meanwhile, phosphate buffer saline treated group showed the lowest wound contraction(69.86%). Histological assessment of wound treated with 6% of 95% ethanol extract of A. longiloba showed distinct epidermal and dermal layer, higher proliferation of fibroblast and more angiogenesis with collagen compared to other wound treated groups.Conclusions: A. longiloba petiole extracts have a wound healing potential and 6% of 95% ethanol extract of A. longiloba is more effective. Further studies are required to understand the wound healing mechanism of action of the extract.

CONVERSE REASONING FOR FULL DEPRESSION-FEATURE MODEL AND PROCESS

A new approach, namely, 'defining protrusion-feature withdepression-parameter' is advanced, which focuses on the shortcomings of protrusion-featurealteration method; The full depression-feature model is built up, and a basic converse reasoningiterative algorithm for machining process is given. The detailed examination has been implemented onthe feature-based modeling system for light industry product (QJFMS) and the converse reasoning onfixture-based machining process is achieved.

Full-scale model tests and nonlinear analysis of prestressed concrete simply supported box girders

Full-scale model tests were carried out on a 30 m span prestressed concrete box girder and a 20 m span prestressed concrete hollow slab. Failure models were prestressed reinforcement tensile failure and crushing of roof concrete,respectively. The ductility indexes of the box girder and hollow slab were 1.99 and 1.23, respectively,according to the energy viewpoint. Based on the horizontal section hypothesis,the nonlinear computation procedure was established using the limited banding law,and it could carry out the entire performance analysis including the unloading,mainly focusing on the ways to achieve the unloading curves computation through stress-strain,moment-curvature and load-displacement curves. Through the procedure,parameters that influence on the bearing capacity,deformation performance and ductility of the structures were analyzed. Those parameters were quantity of prestressed reinforcement and tension coefficients of prestressed reinforcement. From the analysis,some useful conclusions can be obtained.

Monte Carlo study of single-barrier structure based on exclusion model full counting statistics

Different from the usual full counting statistics theoretical work that focuses on the higher order cumulants computation by using cumulant generating function in electrical structures, Monte Carlo simulation of single-barrier structure is performed to obtain time series for two types of widely applicable exclusion models, counter-flows model, and tunnel model. With high-order spectrum analysis of Matlab, the validation of Monte Carlo methods is shown through the extracted first four cumulants from the time series, which are in agreement with those from cumulant generating function. After the comparison between the counter-flows model and the tunnel model in a single barrier structure, it is found that the essential difference between them consists in the strictly holding of Pauli principle in the former and in the statistical consideration of Pauli principle in the latter.

Active suspension with optimal control based on a full vehicle model

The 7-DOF model of a full vehicle with an active suspension is developed in this paper.The model is written into the state equation style.Actuator forces are treated as inputs in the state equations.Based on the basic optimal control theory,the optimal gains for the control system are figured out.So an optimal controller is developed and implemented using Matlab/Simulink,where the Riccati equation with coupling terms is deduced using the Hamilton equation.The all state feedback is chosen for the controller.The gains for all vehicle variables are traded off so that majority of indexes were up to optimal.The active suspension with optimal control is simulated in frequency domain and time domain separately,and compared with a passive suspension.Throughout all the simulation results,the optimal controller developed in this paper works well in the majority of instances.In all,the comfort and ride performance of the vehicle are improved under the active suspension with optimal control.

Modeling and Current Programmed Control of a Bidirectional Full Bridge DC-DC Converter

Modelling of bidirectional full bridge DC-DC converter as one of the most applicable converters has received significant attention. Mathematical modelling reduces the simulation time in comparison with detailed circuit response;moreover it is convenient for controller design purpose. Due to simple and effective methodology, average state space is the most common method among the modelling methods. In this paper a bidirectional full bridge converter is modelled by average state space and for each mode of operations a controller is designed. Attained mathematical model results are in a close agreement with detailed circuit simulation.

A Non-geometrically Similar Model for Predicting the Wake Field of Full-scale Ships

规模效果导致在模型规模和实际轮船的 wake 地之间的大差异，并且在在预言实际轮船的表演的成穴性能和令人激动的力量测试引起差别。因此，从轮船模型的测试数据是什么时候，直接使用了预言实际轮船的表演，测试结果必须受到实验修正。这研究为壳模型的反向的设计建议一个方法。比作一个几何上类似的壳模型，修改模型产生的 wake 地接近一艘实际轮船的。一非 -- 轮船和海洋工程(KRISO ) s 容器轮船(KCS ) 的一个朝鲜研究院的几何上类似的模型被设计。数字模拟用这个模型被执行，并且它的结果与照原尺寸的计算结果相比。由非几何上类似的模型得到照原尺寸的轮船的 wake 领域的变丑方法成功地被用于 KCS。

KT形钢管相贯节点受力性能试验研究

依托某户外剧场钢结构顶棚结构设计,首先对其管桁架关键KT形钢管相贯节点进行了足尺模型试验,测试分析了该节点相贯线、主管及支管应变分布规律。试验结果显示,在最大荷载作用下,相贯节点因支管相贯线附近部分屈服而不能继续承载,其余位置未屈服,表明支管相贯线附近位置是该相贯节点最薄弱位置。然后运用ANSYS有限元软件建立KT形钢管相贯节点有限元模型,将试验结果与有限元分析结果作对比,验证了有限元模型的准确性。最后通过有限元模拟探讨了增大支管厚度以及增设加劲肋对节点受力性能的影响。有限元分析结果显示,增大支管厚度对其受力性能影响较小;增设加劲肋可以有效降低支管相贯线附近位置的最大应力水平,能有效延缓支管屈服,明显提高管桁架节点的承载力。

平面KK型矩形钢管节点静力试验研究

依托某主题广场月牙形艺廊单层网壳钢屋架结构,选取其最不利受力节点,设计了中心插板节点和毂节点两种KK型矩形钢管节点,分别对其足尺模型进行静载试验,测试分析模型节点区域的应变及应力分布规律,对比分析支管端部的位移变化。结果表明:1)设计荷载水平下,两个节点均满足受力要求;毂节点和中心插板节点的最大试验荷载约为等效设计荷载的2.85倍和3.25倍,节点安全储备较高;2)在最大试验荷载作用下,两个节点支管根部与中心构件相贯焊缝附近部分均不同程度地屈服,毂节点圆筒内加劲肋焊缝局部出现开裂;3)相同荷载作用下,中心插板节点相应位置应力应变水平相对较低,故中心插板节点的承载强度较高;4)由试验荷载-位移曲线分析得出毂节点的各肢平均位移比中心插板节点约大13.3%,表明中心插板节点弹性刚度较大。

全程麻醉护理一体化模式联合预见性护理对小儿麻醉复苏期的影响

目的 探讨全程麻醉护理一体化模式联合预见性护理对小儿麻醉复苏期的影响。方法 前瞻性纳入湖南省儿童医院2021年9月至2022年8月收治的116例拟行心脏手术治疗的患儿进行随机对照研究,通过随机双盲抽签法将其分为对照组与观察组,各58例。对照组接受全程麻醉护理一体化模式护理干预,观察组接受全程麻醉护理一体化模式联合预见性护理干预。比较两组手术结束即刻(L1)、入复苏室即刻(L2)、麻醉清醒时(L3)患者麻醉复苏期体征水平;两组麻醉复苏情况及复苏期间并发症发生情况。结果 整体分析发现,两组心率、平均动脉压时间、组间、交互作用比较,差异有统计学意义(P<0.05),进一步两两比较:组内比较,两组组内各时点麻醉复苏期体征水平比较,差异有统计学意义(P<0.05);组间比较,观察组各时点心率、平均动脉压均高于对照组,差异有统计学意义(P<0.05)。观察组自主呼吸恢复时间、自主睁眼时间、拔管时间、出复苏室时间均短于对照组(P<0.05)。观察组并发症总发生率低于对照组,差异有统计学意义(P<0.05)。结论 全程麻醉护理一体化模式联合预见性护理有助于稳定小儿麻醉复苏期体征水平,促进小儿麻醉复苏期恢复,且可降低复苏期间并发症发生率。

基于全价值和全成本模型的农业水价方案及其可行性分析

针对现行农业水价标准过低的问题,选取粮食主产区——黑龙江省为研究区域,从农业用水全价值和全成本出发,利用能值理论分析确定农业用水价值,采用全成本水价法确定用水成本,结合现行水价制定不同情境下农业水资源定价方案;运用双对数模型建立农业用水需求价格函数,揭示水价提升带来的研究区域节水潜力,结合指数分析法确定农户可承受能力,从而判断所制定水价方案的可行性。结果表明:2020年,农业水资源全价值为0.594元/m^(3),地表水与地下水全成本分别为0.180元/m^(3)和0.355元/m^(3);针对设计的3种阶梯水价调整方案,利用2005、2010、2015、2020年进行实证分析,过渡期和长期水价方案平均年节水量分别可达2.72×10^(9)、4.45×10^(9)m^(3),平均年节水潜力分别为12.74%、19.48%,且一阶水价均在农户可承受能力范围,确定为可行方案。本文为研究区农业水价综合改革提供了支持,可结合实际情况逐步提高农业水价到合理水平。

常泰长江大桥组合索塔锚固结构钢-混传剪构造足尺模型试验研究

常泰长江大桥索塔锚固结构采用钢箱-核芯混凝土组合结构,为研究该新型组合索塔锚固结构钢-混传剪构造的受力特性,进行钢-混传剪构造足尺模型试验研究。制作2个锚固结构足尺节段试验模型,通过压剪试验研究锚固结构的荷载~滑移曲线及应力、应变分布等受力特性,并通过有限元模型分析锚固结构的传力机理和各组件的内力分配比例,推导剪力钉剪力计算方法。结果表明:在2.14倍单索最大索力荷载作用下,锚固结构保持弹性状态,钢壁板未产生明显滑移,钢-混界面最大滑移不超过0.25 mm,该锚固结构中钢-混传剪构造至少具有2.14倍的安全系数;荷载作用下,剪力钉剪力从上至下逐渐增大,锚腹板附近底部3排剪力钉剪力较大,钢-混传剪构造至少存在剪力钉和界面摩擦力2种传剪机制,钢-混传剪构造的承载能力显著提高;钢-混传剪构造受力过程分为粘结力传力阶段和局部滑移阶段,剪力钉剪力分布不仅与沿剪切方向长度分布有关,也与荷载的大小线性相关。

全波形发射电流激发下地面瞬变电磁法磁场特征

在过去四十年,大部分关于瞬变电磁法的三维建模和反演研究都聚焦于磁场时间导数,而对于磁场数据研究并不多见.如今,随着超导量子干涉仪(SQUID)技术日益成熟,基于磁场数据的瞬变电磁法探测案例逐渐增多.基于矢量有限单元法,采用频谱法和时步法分别实现了适用于瞬变电磁法磁场数据的三维正演.以低阻覆盖层下的良导体和均匀半空间中板状良导体模型为例,研究了全波形发射电流激发的瞬变电磁法磁场及其时间导数特征,并探讨了二者对深部良导体的探测能力.正演计算结果表明:由于受发射电流全波形效应影响,晚延时磁场随目标体电导率增大而先增强、后减弱,然而即使不考虑全波形效应,磁场时间导数也呈现上述规律;在高阻和低阻围岩情形中,磁场比其时间导数对深部良导体反映更加灵敏,并且晚延时磁场比其时间导数更不易受地磁场背景噪声干扰,说明磁场比其时间导数更适合于深部良导体探测.需要注意的是,发射电流全波形效应降低了瞬变电磁法对深部良导体的识别能力,建议在瞬变电磁法对块状或脉状金属硫化物矿床探测时,尽量采用低基频发射电流波形.

基于KANO模型的门诊患者全方位全流程服务管理可行性分析

目的选取青岛大学附属医院门诊患者作为调查对象,验证使用KANO模型分析门诊全方位全流程服务内容的可行性及应用效果,以期完善门诊服务质量、提高管理水平及患者满意度。方法应用自行设计的基于KANO模型包含诊前、诊中、诊后3个流程的调查问卷,2023年9月1—25日对青岛大学附属医院336例门诊患者进行全方位全流程的调查,并通过质量属性分类法将全部门诊服务内容分类。结果依照KANO模型,全方位全流程服务内容中期望型需求17项、魅力型需求5项、必备型需求6项、无差异型需求11项。结论在门诊全方位全流程服务过程中,应在确保必备型需求的同时,注重期望型需求的改善,致力于魅力型需求的提升,有助于针对性地改进门诊护理服务过程中的不足,从而更好地满足门诊患者多方面的服务需求,提高患者的满意度,实现门诊医疗服务质量的提升。

海上风电低频输电系统快速母线保护

海上风电低频输电系统母线故障后,换流器型电源等效电势与阻抗因控制的切换与调整过程,不再像传统电网可视为恒定。文中理论分析了母线电流差动保护适应性,明确故障控制策略对差动保护灵敏度的影响方式。利用母线区内外故障所对应的故障等效模型不同,提出基于时域全量模型识别的母线保护。该保护原理反映被保护元件自身拓扑的变化,理论上具有不受电源特性影响的优势,同样适用于其他换流器型电网。同时,所提保护在时域中实现,不存在相量提取问题,动作速度快。最后,在PSCAD/EMTDC中搭建了仿真模型,验证了所提母线保护的可靠性和快速性。

基于全范围头部姿态估计的教师注意力识别算法

探究教师注意力对于评估课堂教师行为具有极其重要的研究价值。然而,现有的教师注意力识别算法存在无法应对极端头部姿态角度等问题。为此,提出一种基于6DRep Net360模型的教师注意力状态识别算法,提升极端角度中头部姿态估计算法的准确性。相较于传统的依赖条件判断来分类教师注意力状态的方法,设计一种基于支持向量机(SVM)的教师注意力分类模型,对复杂头部姿态角度进行注意力状态的精准识别。为进一步解决算法稳定性和准确性带来的误差数据,提出基于滑动窗口的数据清洗算法,有效提高整体识别结果的真实性和可靠性。通过在构建的CCNUTeacherS tat e数据集上进行一系列的算法评估,实验结果表明,所提出的教师注意力识别算法在CCNUTeacherS tate数据集上达到了90.67%的准确率。