Investigating the Effect of Relative Width on Momentum Transfer between Main Channel and Floodplain in Rough Rectangular Compound Channel Sunder Varius Relative Depth Condition

Compound section is referred to a section the surface of which is made of several sub-sections with different flow characteristics. The difference in the hydraulic and geometry characteristics causes a complexity in flow hydraulic and creates an interaction between the main channel and floodplains, resulting in an apparent shear stress and a transverse momentum transfer. The amount of such a stress plays an important role in many river engineering measures [1]. Due to the flow complexity, the common approximate analytical methods are not enough to identify the flow profile. The FLOW3D Software with its great features in three-dimensional analysis of flow field is used as a tool to investigate the shear stress in a direct symmetrical compound rectangular channel. After the simulation of models, it is found that an increase in the relative width and relative depth parameters decreases the percentage of apparent shear stress and an increase in the relative roughness causes it to be increased [2].

基于冲刷指数的雨水管渠冲刷淤积分析

流速、雷诺数、充满度等单因素指标虽然与雨水管渠的冲刷和淤积量有一定的关联,但是通过单因素指标不足以全面地判断雨水管道的冲刷和淤积。在起动流速和止动流速的基础上,提出了冲刷指数的概念。结合连续非恒定流不同工况下冲刷和淤积量模拟,计算了流速、雷诺数、充满度、冲刷指数4个因素与冲刷量的灰色关联度,其关联度大小依次为:冲刷指数>雷诺数>充满度>流速。根据不同工况的恒定流模型实验的结果,其关联度大小依次为:冲刷指数>>流速>雷诺数>充满度。可以认为,在恒定流与非恒定流工况下,冲刷量和冲刷指数有显著的强相关性,冲刷指数能代替具体的冲刷量计算实现对冲刷程度和趋势的合理判断。

基于高分一号遥感数据的张家口地区植被分布影响因素研究

研究基于高分一号遥感影像数据,对张家口地区的植被分布规律进行了深度分析,并探讨了其与水资源之间的关系。使用归一化公式计算出植被覆盖度,运用聚类自相关分析揭示了植被分布的空间正相关性。结合降雨量数据和张家口地区2 046个地下水埋深实测数据,利用GIS空间分析方法,探讨了植被覆盖度、植被分布与降雨量和地下水位埋深的关系。结果显示,张家口地区的植被覆盖度与降雨量显著正相关,相关系数高达0.88;地下水与植被覆盖度的关系曲线呈双峰形态,在地下水埋深7.1 m和12.7 m时达到峰值;当地下水位埋深在4~8 m范围内时,各类植被的分布面积均显著增加。

藏族年龄相关性白内障患者眼球生物学参数特征分析

目的:比较藏族与汉族年龄相关性白内障患者眼球生物学参数的差异,分析藏族患者眼球生物学参数的分布特征。方法:回顾性队列研究。收集2019-01/2020-12就诊于我院的年龄相关性白内障患者661例1 030眼,其中藏族患者483例739眼,汉族患者178例291眼。术前所有患者均采用IOL Master 500测量眼轴长度、前房深度、角膜曲率、散光及散光轴向。结果:藏族年龄相关性白内障患者眼轴长度为23.33(22.81,23.86)mm,前房深度为3.04(2.79,3.30)mm,散光度为0.73(0.47,1.07)D,平均角膜曲率为43.89±1.35 D,较汉族患者眼轴短,角膜曲率小(均P<0.05)。藏族患者的年龄与眼轴长度和前房深度均呈负相关,而与平均角膜曲率呈正相关(均P<0.05)。藏族患者中男性患者较女性患者眼轴更长、前房更深、角膜更平坦(均P<0.05)。结论:藏族与汉族年龄相关性白内障患者的眼球生物学参数存在差异,不同年龄和性别藏族患者眼球生物学参数的分布有所变化。

混凝土粗糙表观对DIC测量误差的影响研究

混凝土构件在长期服役过程中受到风浪、温度应力、腐蚀等外部环境侵蚀,导致混凝土表观粗糙不平。采用数字图像相关技术(DIC)计算力学响应下的混凝土表面应变场时,粗糙表观超过相机景深会引起离焦现象致使散斑退相关,使得DIC测量误差增大。针对此问题,基于3D-DIC系统计算物体表面三维形貌并以Z轴高度极差与平均灰度共同表征混凝土表面粗糙度,结合DIC成像规律与混凝土表面粗糙度的大小预留足够的景深并通过混凝土三点弯实验验证。结果表明:对于粗糙度R_(S)(4.37mm,139)的混凝土,预留景深0.81mm,DIC数据平均偏差高达42%;预留景深4.48mm,DIC数据平均偏差仅12%。

预装式疏水性丙烯酸酯类人工晶体和同轴微切口对年龄相关性白内障疗效分析

目的探讨与分析预装式疏水性丙烯酸酯类人工晶体和同轴微切口对年龄相关性白内障的疗效影响。方法选择2020年8月—2023年5月在蓝田华阳眼科医院诊治的80例年龄相关性白内障患者作为研究对象,根据随机数表法将其分为对照组和研究组,每组40例。所有手术均由同一位医师完成,都采用预装式疏水性丙烯酸酯类人工晶体植入,研究组行2.2 mm同轴透明角膜隧道微切口,对照组行3.0 mm透明角膜隧道切口,比较两组的最佳矫正、并发症发生情况、角膜散光度与前房深度变化情况。结果研究组术后1周与术后1个月的最佳矫正视力都高于对照组,差异有统计学意义(P<0.05);两组术后1个月的最高矫正视力与术后1周相比都升高,差异有统计学意义(P<0.05)。研究组术后1个月的角膜水肿、眼内炎、晶体混浊、囊膜破损等并发症发生率显著低于对照组,差异有统计学意义(P<0.05)。研究组术后1周与术后1个月的角膜散光度都低于对照组,差异有统计学意义(P<0.05);两组术后1个月的角膜散光度与术后1周相比都降低,差异有统计学意义(P<0.05)。研究组术后1周与术后1个月的前房深度都高于对照组,差异有统计学意义(P<0.05);研究组与对照组术后1个月与术后1周的前房深度比较,差异无统计学意义(P>0.05)。结论预装式疏水性丙烯酸酯类人工晶体联合同轴微切口在年龄相关性白内障患者的应用并不会影响患者的前房深度,能减少角膜散光度,提高患者的术后视力,减少并发症的发生。

Depth inversion in coastal water based on SAR image of waves

Wave-number spectrum technique is proposed to retrieve coastal water depths by means of Synthetic Aperture Radar （SAR） image of waves. Based on the general dispersion relation of ocean waves the wavelength changes of a surface wave over varying water depths can be derived from SAR. Approaching the analysis of SAR images of waves and using the general dispersion relation of ocean waves, this indirect technique of remote sensing bathymetry has been applied to a coastal region of Xiapu in Fujian Province, China. Results show that this technique is suitable for the coastal waters especially for the near-shore regions with variable water depths.

Evaluation of EEG β2/θ -ratio and channel locations in measuring anesthesia depth

In this paper, the ratio of powers in the frequency bands of β2 and θ waves in EEG signals (termed as the β2/θ -ratio) was introduced as a potential enhancement in measuring anesthesia depth. The β2/θ -ratio was compared to the relative β-ratio which had been commercially used in the BIS monitor. Sensitivity and reliability of the β2/θ -ratio and EEG measurement locations were analyzed for their effectiveness in measuring anesthesia depth during different stages of propofol induced anesthesia (awake, induction, maintenance, and emergence). The analysis indicated that 1) the relative β -ratio and β2/θ-ratio derived from the prefrontal, frontal, and the central cortex EEG signals were of substantial sensitivity for capturing anesthesia depth changes. 2) Certain channel positions in the frontal part of the cortex, such as , had the combined benefits of substantial sensitivity and noise resistance. 3) The β2/θ-ratio captured the initial excitation, while the relative β -ratio did not. 4) In the maintenance and emergence stages, the β2/θ -ratio showed improved reliability. Implications: The ratio of powers in EEG frequency bands and derived from the frontal cortex EEG channels has combined benefits of substantial sensitivity and noise resistance in measuring anesthesia depth.

Probabilistic Analysis of Reinforced Concrete Carbonation Depth

Concrete carbonation relates to the diffusion of CO2 inthe atmosphere through the concrete pores and to the dissolution of the hydrates. A great deal of uncertainty still remains in this subject as a result of the random nature of the infiltration of these aggressive agents as well as the material and structural properties of reinforced concrete. Consequently, in order to determine the degradation of these structures with time, it is necessary to approach the subject from a probabilistic point of view that it considers the uncertainties involved with the geometrical dimensions of these structures, with the material characteristics and with the environment and the subsequent deterioration that it provokes. The aim of this paper is the evaluation of carbonation depth (Xc) from a probabilistic analysis, focusing specifically on the study of the randomness of the most influential parameters on the reinforced concrete carbonation.

LINEAR GRAVITY WAVES ON MAXWELL FLUIDS OF FINITE DEPTH

Linear surface gravity waves on Maxwell viscoelastic fluids with finite depth are studied in this paper.A dispersion equation describing the spatial decay of the gravity wave in finite depth is derived.A dimensionless memory(time)number θ is introduced.The dispersion equation for the pure viscous fluid will be a specific case of the dispersion equation for the viscoelastic fluid as θ=0.The complex dispersion equation is numerically solved to investigate the dispersion relation.The influences of θ and water depth on the dispersion characteristics and wave decay are discussed.It is found that the role of elasticity for the Maxwell fluid is to make the surface gravity wave on the Maxwell fluid behave more like the surface gravity wave on the inviscid fluid.

Effect of model errors in ambient air humidity on the aerosol optical depth obtained via aerosol hygroscopicity in eastern China in the Atmospheric Chemistry and Climate Model Intercomparison Project datasets

This analysis of the multi-model aerosol optical depth (AOD) in eastern China using the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) datasets shows that the global models underestimate the AOD by 33% and 44% in southern and northern China, respectively, and decrease the relative humidity (RH) of the air in the surface layer to 71%–80%, which is less than the RH of 77%–92% in reanalysis meteorological datasets. This indicates that the low biases in the RH partially account for the errors in the AOD. The AOD is recalculated based on the model aerosol concentrations and the reanalysis humidity data. Improving the mean value of the RH increases the multi-model annual mean AOD by 45% in southern China and by 33% in June–August in northern China. This method of improving the AOD is successful in most of the ACCMIP models, but it is unlikely to be successful in GISS-E2-R, in which the plot of its AOD efficiency against RH strongly deviates from the rest of the models. The effect of the improvement in the modeled RH on the AOD depends on the concentration of aerosols. The shape error in the frequency distribution of the RH is likely to be more important than the error in the mean value of the RH, but this requires further research.

A Study on Constructing Sense Relations

An empirical study is conducted to examine the effect of constructing sense relations in vocabulary teaching. Fifty subjects are divided into two groups： the controlled group which was taught with traditional method, and the experimental group to which sense relation strategy was applied in vocabulary instruction. At the end of the experiment instruction, a test （depth of vocabulary knowledge measure） was given to examine the teaching effects of the two vocabulary teaching strategies. The target words in the tests were selected from the word list that had been taught during the experiment time. A delayed vocabulary posttest was given to the subjects two weeks after examining the long-term retention effect. The third test was administered with different targets words which were selected from a different intensive reading material which wass new to the subjects. The experiment proves that constructing sense relations in vocabulary teaching could produce satisfactory results by enhancing students＇ lexical capacity and long-term retention.

Comparison of Depth Dose Distributions Using Cerenkov Fiber-Optic Dosimeter and Monte Carlo Simulation for HDR Brachytherapy

In this study, we fabricated a Cerenkov fiber-optic dosimeter (CFOD) without any scintillator to measure Cerenkov radiation signals owing to gamma-rays. The relative depth dose (RDD) distributions of Ir-192 HDR brachytherapy source were obtained by using the CFOD based on a subtraction method and the RDD curve was compared with the simulation result of Monte Carlo N-particle extended transport code (MCNPX). Finally, we demonstrated that the CFOD can be used to measure real-time dose information for HDR brachytherapy.

与花岗岩有关金属成矿系统的时-空-物结构初探

与花岗岩有关的矿床是金属矿产资源的重要来源,对该类矿床成矿作用的持续时间、成矿深度、成矿规模的研究等鲜有报道,但这些科学问题的解决却对找矿预测具有重要参考价值。本文对前人相关研究成果进行了初步总结认为:与花岗岩有关的成矿作用持续时间一般约为1 Ma,但也可持续更长时间;成矿深度一般不超过5~10 km;成矿系统的垂向延深一般5~10 km,水平延伸一般不超过10~30 km;热液矿化蚀变空间分带的内因可能主要是离子电位和离子半径的差异,围岩的热导率可能是矿化蚀变空间分带的主要外因之一。

基于改进DRRG的自然场景文本检测算法

随着人们对场景文本检测领域的探索,对于自然场景中较规则文本的检测结果较好,然而对于任意方向的文本和复杂背景图像文本检测结果依然不理想。基于此,提出了一种改进的深度关系推理图网络模型。模型通过不同于anchor思想的文本组件预测部分,直接预测文本行,然后利用深度关系推理网络,推理出待检测文本行。同时引入Resnet50和SENet网络,提高模型特征提取能力和模型鲁棒性。通过在CTW1500和ICDAR2015两个数据集上对改良的模型进行评价,证明了改进算法的可行性。

数字金融发展与区域创新绩效差距

伴随科技与金融市场的深度融合,数字金融对区域创新差距产生了巨大影响。利用2011—2018年中国278个城市样本,基于关系数据分析范式,采用二次指派程序,从全样本、分时期、分年度、分地区四个层面和数字金融覆盖广度、使用深度、数字化程度三个维度对数字金融发展与地区间创新的关系进行了考察。结果显示:数字金融的平衡发展有利于缩小我国地区间创新绩效差距,且作用逐年提升;覆盖广度比使用深度的贡献度大,数字化程度则不显著。从地区异质性视角看,数字金融缩小地区间创新差距的作用只在中、东部地区显著,且覆盖广度与使用深度的影响存在差异。我国现阶段应重视并充分发挥数字金融的潜力,缩小区域间创新水平差距,更好地实现包容性发展的政策目标。

混凝土搅拌站废水对不同等级混凝土碳化性能的影响

使用含固量为12%的搅拌站废水等质量替代饮用水拌制C20、C40、C60混凝土。研究了废水的物理化学性质及微观结构。分析了不同废水替代率(0、25%、50%、75%、100%)下混凝土的抗碳化性能及作用机理。利用灰色关联熵探讨了影响混凝土碳化深度的关键因素。研究结果表明,废水降低了混凝土的抗碳化能力。水胶比是影响混凝土碳化深度的最关键因素,废水是影响碳化深度的直接因素。废水粉末呈多孔颗粒状,主要由Ca(OH)_(2)、SiO_(2)、C-S-H组成。

潜艇运动激发的表面波

A moving submarine can generate internal waves,as well as extremely small free surface waves,in a fluid with density stratification.In this study,the internal and free surface wave wakes caused by a moving submarine in two layers of constant density fluid were studied numerically using the commercial software STAR-CCM+.The realizable k–εturbulence model was used to solve the Reynolds-averaged Navier–Stokes equation,and the volume of the fluid method was used to monitor the fluctuations of the internal interface and free surface.Different cases of a moving submarine with different cruising speeds and relative diving depths were studied.Results showed that the maximum fluctuation amplitude of the free surface increased as the speed of the submarine increased;however,the maximum fluctuation amplitude of the internal interface first decreased and then increased.When the submarine moved at the maximum cruising speed,the maximum fluctuation amplitude of the free surface decreased as the diving depth increased,while the wavelength of the free surface wave was basically the same.If the submarine moved at the minimum cruising speed,then the wave elevation in the free surface was extremely small,but the internal surface had obviously large-amplitude internal waves,and the relative diving depth had a great influence on internal waves.

府际理论视域下横琴粤澳深度合作区经济协作路径研究

非连续性社会制度背景下的社会经济体系为澳门特别行政区与横琴粤澳深度合作区的共商共建共管共用机制带来了巨大挑战。与传统的省际间的合作不同,横琴粤澳深度合作区的治理分属两种社会制度和三级政府合作,形成了具有纵向、横向和斜向三个维度的多级政府的复杂协调治理特例。对此,本文探讨总结了横琴粤澳深度合作区在多级政府背景下在经济领域协调治理的新路径与机制。

Monocular Vision-based Two-stage Iterative Algorithm for Relative Position and Attitude Estimation of Docking Spacecraft

Visual sensors are used to measure the relative state of the chaser spacecraft to the target spacecraft during close range ren- dezvous phases. This article proposes a two-stage iterative algorithm based on an inverse projection ray approach to address the relative position and attitude estimation by using feature points and monocular vision. It consists of two stages： absolute orienta- tion and depth recovery. In the first stage, Umeyama＇s algorithm is used to fit the three-dimensional （3D） model set and estimate the 3D point set while in the second stage, the depths of the observed feature points are estimated. This procedure is repeated until the result converges. Moreover, the effectiveness and convergence of the proposed algorithm are verified through theoreti- cal analysis and mathematical simulation.