Improvement of Temperature Drop Model Parameters for 4200mm/3500mm Rolling of Baosteel Medium and Thick Plate

Based on the temperature situation during the rolling process of 4200 mm/3500 mm medium and thick plates at Baosteel,this article analyzes the influencing factors of temperature changes during the rolling process from the perspective of heat transfer theory and the temperature change law during the rolling process.The temperature loss during the four rolling processes is tracked on site,and the temperature drop model parameters during the rolling process of 4200mm/3500mm medium and thick plates at Baosteel are quantitatively provided.It is applied to actual rolling production and has achieved good results.

An Improved Level Set Approach to the Simulation of Drop and Bubble Motion

An improved level set approach for computing the incompressibletwo-phase flow with significantly de- formed free interface ispresented. The control volume formulation with the semi-implicitmethod for pressure-linked equations consistent (SIMPLEC) algorithmincorporated is used to solve the governing equations on a staggeredgrid. Several improvements concerning the computational grid,interface update, reinitialization procedure etc. are tested Andfound to be effective in promoting the convergence and numericalstability.

Quantitative Evaluation of the Sea-level Drop at the End-Permian: Based on Reefs

The amplitude of pre-Quaternary sea level drop, H, can be calculated by usingthe formula H = D + To, where To is the original thickness from the top of the tidal deposits onthe reef core to the bottom of the tidal deposits on the reef front, or to the bottom of the ancientmeteoric vadose zone, or to the edge of the mixed-water dolostone zone. The identity and similaritybetween the sea-level drop amplitudes calculated from different reefs far away from each otherindicates that such sea-level changes are eustatic rather than relative changes. Evidence of anend-Permian sea-level drop has been found on the Changxingian (i.e. the end of the Palaeofusulinazone) reefs at Ziyun in South China, including algal laminated deposits, sabkha-related dolostone,desiccation cracks, dissolution collapse breccia. According to calculation based on the meteoricdissolution zone of the reef-core sequence at Ziyun, Guizhou province, the amplitude of thesea-level drop at the end-Permian is about 89.3 m. Calculation via the dolomitized upper part of theChangxingian reef in Lichuan, Hubei Province, yields an 88.9 m amplitude of the sea-level drop atthe end-Permian. Comparison shows that the sea-level drop recorded in the two distantly locatedreefs may be of eustatic type. So the amplitude of the sea level drop of the Tethys Sea at theend-Permian might be at least 89.3 m.

Study on determination of stress level by seismic stress drops and the stress axis de-flections before and after large earthquakes

To obtain the stress level at the earthquake source, this paper sets forth the solution of the stress magnitude at the earthquake source by seismic stress drop and the stress axis deflections before and after large earthquakes. The pre-seismic and post-seismic stress direction can be statistically determined by a large collection of foreshock and aftershock focal mechanism data while the stress drop can be determined through the source fracture inversion from seismic wave data or crust deformation data. The paper attempts to make a fundamental contribution to seismic dynamics.

Drop failure modes of Sn-3.0Ag-0.5Cu solder joints in wafer level chip scale package

To reveal the drop failure modes of the wafer level chip scale packages （WLCSPs） with Sn-3.0Ag-0.5Cu solder joints, board level drop tests were performed according to the JEDEC standard. Six failure modes were identified, i.e., short FR-4 cracks and complete FR-4 cracks at the printing circuit board （PCB） side, split between redistribution layer （RDL） and Cu under bump metallization （UBM）, RDL fracture, bulk cracks and partial bulk and intermetallic compound （IMC） cracks at the chip side. For the outmost solder joints, complete FR-4 cracks tended to occur, due to large deformation of PCB and low strength of FR-4 dielectric layer. The formation of complete FR-4 cracks largely absorbed the impact energy, resulting in the absence of other failure modes. For the inner solder joints, the absorption of impact energy by the short FR-4 cracks was limited, resulting in other failure modes at the chip side.

Co-seismic Water Level and Temperature Responses of Some Wells to Far-Field Strong Earthquakes and Their Mechanisms

The observation of water temperature in deep wells has been carried out for more than 20 years in China.However,study on the mechanism of water temperature response to earthquakes is inadequate.During the study of the co-seismic response characteristics of water level and temperature in 121 wells within the China subsurface fluid monitoring network at the time of the December 26,2004,M-S8.7 Indonesia earthquake,we found regular response characteristics,that is,when the water level in a deep well oscillates,the water temperature in the same well will mostly experience a cycle from dropping to restoration at the same time.The process will continue for dozens of minutes to several hours.In order to confirm the observed phenomenon,we collected the digital water level and temperature observation data for 39 far-field strong earthquakes from the Tangshan well in Hebei Province(with the data set beginning in 2001).The same response characteristics were observed.Based on the analysis of the influencing factors that may cause the water temperature drop,the authors suggest the gas escape mechanism for co-seismic water temperature drop and posit two main factors that influence the water temperature drop during the process of gas escape.Finally,the authors provide a rational explanation of some observed phenomena based on the mechanism.

Case analysis of water exchange between the Bohai and Yellow Seas in response to high winds in winter

Based on the data from a special project titled China's Offshore Marine Integrated Investigation and Evaluation as well as Regional Ocean Modeling Systems(ROMS)diagnostic numerical model,we studied the influence of high wind processes on the circulation and water exchange between the Bohai and Yellow Seas(BYS)in winter.The results show that the vertical structure of the Yellow Sea Warm Current(YSWC)is relatively uniform under condition of high winds,showing obvious barotropic features.However,this flow is not a stable mean flow,showing strong paroxysmal and reciprocating characteristics.A comparison of the changes in sea level suggests that the intensity of the northwards upwind flow is consistent with the abnormal fluctuations in the sea level.It indicates that the upwind flow is closely related to the water exchange between the BYS.The impact of high wind processes on the water exchange between the BYS is enormous.It can make the flux through the Bohai Strait,as well as that through the mouth of each constituent bay(i.e.,Liaodong Bay,Bohai Bay,and Laizhou Bay)far greater than usual,resulting in a significant increase in the water exchange rate.The exchange capacity,which is about 8%of the total volume of the Bohai Sea,can be completed in a few days.Therefore,the water exchange of the Bohai Sea may be completed by only a few occasional high wind processes in winter.

THE HYDROLOGICAL CHARACTERISTICS AND WATER BUDGET OF QINGHAI LAKE DRAINAGE BASIN

The rapid shrinkage of the surface area reflects the long-term deficit water budget of Qinghai Lake. Study of the yearly hydrology and meteorology in the lake catchment basin and the hydrologic factors as well as water budget led to the conclusion that evaporation exceeding the water input resulted in the drop of lake level, thai the obvious decrease of runoff to the lake and precipitation on the catchment accelerated the falling of lake level before 1987. and that increase of about 6.7% in rainfall on the whole basin will balance the lake’s water budget.

Effect of viscosity on motion of splashing crown in high speed drop impact

A splashing crown is commonly observed when a high-speed drop impacts a liquid film. The influence of the liquid viscosity on the crown＇s evolution is not yet clear. We review several existing theories of this problem, and carry out a series of numerical simulations. We find that a three-segment model can describe the crown＇s motion. In the very early stage when the crown is barely visible, the influence of viscosity is small. Later, a shallow water approach used in most existing models is applicable as long as the initial conditions are formulated properly. They depend on viscous dissipation in the intermediate period. Preliminary estimation based on a dissipation function is proposed to characterize the influence of viscosity in this problem.

On the Conduction Mechanism of Silicate Glass Doped by Oxide Compounds of Ruthenium (Thick Film Resistors)

The results of the investigation of conduction mechanism of silicate glass doped by oxide compounds of ruthenium (thick film resistor) are reported. The formation of diffusion zones in the softened glass during firing process of the mixture of the glass and the dopant powders is considered. As the result the doping glass becomes conductive. These diffusion zones have higher conductivity and act as percolation levels for the free charge carriers. The effect of tem-perature and duration of firing process on the conductivity of doped glass is considered. Experimental results are in a good agreement with the model.

单液滴撞击平面液膜飞溅过程的CLSVOF模拟

采用CLSVOF(coupled level set and volume of fluid)方法对单液滴撞击平面液膜初期的飞溅过程进行了数值模拟,探讨了撞击速度和液膜厚度对撞击后形成冠状水花形态及扩展直径的影响。结果显示,扩展直径随撞击速度的增大而增大,随液膜厚度的增大而减小,CLSVOF方法可较好地用于液滴撞击过程的数值计算。

Comprehensive Analysis and Artificial Intelligent Simulation of Land Subsidence of Beijing, China

Mechanism and modeling of the land subsidence are complex because of the complicate geological background in Beijing, China. This paper analyzed the spatial relationship between land subsidence and three factors, including the change of groundwater level, the thickness of compressible sediments and the building area by using remote sensing and GIS tools in the upper-middle part of alluvial-proluvial plain fan of the Chaobai River in Beijing. Based on the spatial analysis of the land subsidence and three factors, there exist significant non-linear relationship between the vertical displacement and three factors. The Back Propagation Neural Network (BPN) model combined with Genetic Algorithm (GA) was used to simulate regional distribution of the land subsidence. Results showed that at field scale, the groundwater level and land subsidence showed a significant linear relationship. However, at regional scale, the spatial distribution of groundwater depletion funnel did not overlap with the land subsidence funnel. As to the factor of compressible strata, the places with the biggest compressible strata thickness did not have the largest vertical displacement. The distributions of building area and land subsidence have no obvious spatial relationships. The BPN-GA model simulation results illustrated that the accuracy of the trained model during fifty years is acceptable with an error of 51% of verification data less than 20 mm and the average of the absolute error about 32 mm. The BPN model could be utilized to simulate the general distribution of land subsidence in the study area. Overall, this work contributes to better understand the complex relationship between the land subsidence and three influencing factors. And the distribution of the land subsidence can be simulated by the trained BPN-GA model with the limited available dada and acceptable accuracy.

Analytical and Experimental Studies on Wave Scattering by a Horizontal Perforated Plate at the Still Water Level

This research investigates water-wave scattering via a horizontal perforated plate fixed at the still water level through analytical studies and physical model tests.The velocity potential decomposition method is combined with an efficient iterative algorithm to develop an analytical solution in which the quadratic pressure drop condition is imposed on the horizontal perforated plate.The analytical results are in good agreement with the results of an independently developed iterative boundary element method(BEM)solution.Experimental tests are carried out in a wave flume to measure the reflection coefficient and transmission coefficient of the horizontal perforated plate,and the analytical results agree reasonably well with the experimental data.The influence of various structural parameters of the horizontal perforated plate on the hydrodynamic parameters of reflection coefficient,transmission coefficient,energy-loss coefficient,and wave force are analyzed on the basis of the analytical solution.Useful results for the practical engineering application of horizontal perforated plates are also presented.

Combined Bearing Capacity of Spudcans on a Double Layer Deposit of Strong-Over-Weak Clays

An extreme sea storm process can lead to a jack-up rig under the combined loading condition of vertical load(V), horizontal load(H), and moment(M) to have stability problems. This paper presents the analysis of combined bearing capacities of a circular spudcan on layered clays with a strong layer overlying a comparatively weaker layer. Numerical models combined with displacement-based load tests, swipe tests, and constant ratio displacement probe tests are adopted to calculate the uniaxial bearing capacities, failure envelopes in combined V-H, V-M planes, and failure envelopes in a combined V-H-M load space, respectively. A parametric study on the effects of vertical load level V, the layer strength ratio s_(u,t)/s_(u,b), and the hard layer thickness t_1 on the bearing capacities is then performed. Results show that the vertical load level is a key factor that influences the values of H and M and the size of the H-M failure envelope. The existence of the underlying weak clay decreases the bearing capacities in all directions, and the vertical capacity Vult is affected more than the horizontal(H_(ult)) and moment(M_(ult)) capacities based on a single uniform deposit. The influence of the underlying weak clay on H-M failure envelope is mainly shown where H and M are coupled in the same direction. In contrast, little difference is observed when H and M are coupled in opposite directions.

陕北榆林地区植被好转背景下面临的生态环境新挑战

近几十年来,随着退耕还林还草等政策的实施,榆林地区植被覆盖度明显提高,生态环境明显好转。但与此同时,河流流量减少,地下水位下降等问题也逐渐凸显,对其进行梳理总结并提出针对性的对策建议对榆林地区可持续发展具有重要意义。笔者在充分收集前人资料的基础上,全面梳理了榆林地区近年来出现的各种问题,并分析了可能的原因,最后提出对策建议。通过研究发现,近20年以来榆林地区植被指数呈现明显增加的趋势,林草地面积大幅度增加,荒漠化土地面积显著减少。同时,榆林地区较大的河流径流量近50年来普遍减少,尤其以无定河、秃尾河、窟野河最为明显。区域地下水位普遍下降,降幅2~10 m不等。近年来,在西北部毛乌素沙地,出现了大规模开垦耕地的现象。针对前述的问题,建议榆林地区坚决落实以水定产的政策,加强区内水资源优化配置,加大矿井水和黄河水的利用,以灌木林和草本为主进行植被恢复,加强耕地开垦区地下水位和土地沙化的监测。研究榆林地区在新时期出现的生态环境问题及对策建议对于黄河中游生态脆弱区的资源型城市的可持续发展有一定的借鉴意义。

Angio-OCT引导IQ577TMIRIDEX微脉冲激光联合抗新生血管药物治疗糖尿病性黄斑水肿的临床效果

目的探究Angio-OCT引导IQ577TMIRIDEX微脉冲激光联合抗新生血管药物治疗糖尿病性黄斑水肿的临床效果。方法回顾性分析2019年1月至2021年1月乐平市人民医院眼科收治的60例糖尿病黄斑水肿患者的临床资料,按照不同治疗方案将其分为联合治疗组(30例)与单纯抗血管内皮生长因子(VEGF)组(30例),联合治疗组患者采用Angio-OCT引导IQ577TMIRIDEX微脉冲激光联合抗VEGF药物进行治疗,单纯抗VEGF组采用抗VEGF药物进行玻璃体腔注射治疗,比较两组患者的最佳矫正视力(BCVA)、黄斑中心凹厚度(CMT)、黄斑中心凹无血管区面积(FAZ)、浅层毛细血管丛(SCP)、深层毛细血管丛(DCP)的平均血流密度(VD)的变化,并评估治疗安全性。结果两组患者治疗1、2、3个月时的BCVA均高于本组治疗前,治疗2、3个月时的BCVA均高于治疗1个月时,治疗3个月时的BCVA高于治疗2个月时,差异有统计学意义(P<0.05)。治疗2、3个月时,单纯抗VEGF组的BCVA均低于同时刻联合治疗组,差异有统计学意义(P<0.05)。两组患者治疗1、2、3个月时的CMT均低于本组治疗前,治疗2、3个月时的CMT均低于治疗1个月时,治疗3个月时的CMT低于治疗2个月时,差异有统计学意义(P<0.05)。治疗1、2、3个月时,单纯抗VEGF组的CMT均高于同时刻联合治疗组,差异有统计学意义(P<0.05)。两组患者治疗前后的FAZ、SCP VD、DCP VD比较,差异无统计学意义(P>0.05);两组患者均未出现明显眼部或全身性不良反应。结论在糖尿病黄斑水肿患者的治疗中,采用Angio-OCT引导IQ577TMIRIDEX微脉冲激光联合抗VEGF药物能够有效地改善患者的视力水平,降低黄斑中心凹厚度,提升患者的治疗效果,方法操作简便,安全性较高,值得临床应用与推广。

Numerical simulation of Marangoni effects of single drops induced by interphase mass transfer in liquid-liquid extraction systems by the level set method

The mathematical model of mass transfer-induced Marangoni effect is formulated. The drop surface evolution is captured by the level set method, in which the interface is represented by the embedded set of zero level of a scalar distance function defined in the whole computational domain. Numerical simulation of the Marangoni effect induced by interphase mass transfer to/from deformable single drops in unsteady motion in liquid-liquid extraction systems is performed in a Eulerian axisymmetric reference frame. The occurrence and development of the Marangoni effect are simulated, and the re- sults are in good agreement with the classical theoretical analysis and previous simulation.

极端生态环境水循环关键参量监测技术研究现状与进展

针对高寒和干旱极端生态环境水循环变化对国家生态安全的重要性,需要开展水循环关键参量监测设备与技术研究。本文重点围绕水循环关键参量野外原位/移动/非接触式、自动、稳定监测等技术难点,开展了一系列监测生态系统水-土-气-冰-雪的关键参量的新技术设备研究。通过构建基于物联网的天地一体化生态系统监测体系,打破行业技术壁垒,促进工程技术、地质学、计算机科学等不同领域的跨学科合作,共同开展极端生态环境水循环关键参量监测技术研究与创新,并将实现对重要生态功能区的大范围、全天候、立体化监测,对推进我国生态文明建设具有重要支撑作用,促进并实现我国生态监测技术的综合应用和发展。

水位骤降作用下浔江岸堤滑坡稳定性分析及治理方案研究

为研究水位骤降对滑坡稳定性的影响,以浔江三布堤滑坡为例,根据详细的现场勘察及水库运营资料,利用FLAC 3D有限差分岩土分析软件,对水位骤降条件下堤岸滑坡的稳定性进行模拟计算,从滑坡稳定性系数、滑动面及滑坡位移等方面分析,并结合现场勘察对该滑坡治理方案进行模拟。结果表明浔江水位从十年一遇洪水位(37.2 m)骤降至正常水位22.3 m后,堤岸滑坡稳定性系数从1.60降至0.81,由于水位快速持续下降引、诱发滑体失稳破坏;进行压石护坡治理后,水位骤降工况下堤岸滑坡稳定性系数从0.81增加到1.20,为滑坡治理提供了高效且低成本的治理方案。

三种干预方法对隐匿性近视儿童相关眼部生物学参数的影响

目的:观察三种不同干预方法对隐匿性近视儿童相关眼部生物学参数的影响,探究其对隐匿性近视儿童的不同控制作用。方法:前瞻性队列同期对照试验研究。选取2021-12/2022-05在承德医学院附属医院眼科门诊初次诊断为隐匿性近视且未经过任何相应近视控制训练的患儿60例120眼。随机分为3组,A组20例40眼给予0.01%阿托品滴眼液,B组20例40眼接受翻转拍视力训练,C组20例40眼给予七叶洋地黄双苷滴眼液。随访12 mo,观察三组患儿初诊,干预后6、12 mo时等效球镜度数(SE)、眼轴长度(AL)、角膜曲率(CC)、调节灵敏度(AF)、黄斑区视网膜厚度的变化情况。结果:干预后6、12 mo,三组患儿AL、SE和AF较初诊有差异(均P<0.05),干预后6 mo与12 mo比较均有差异(均P<0.05),B组和C组SE和AF均高于A组(均P<0.05),干预前后CC比较无差异(均P>0.05)。三组患儿干预后6、12 mo外环颞侧、鼻侧、下方、黄斑中心凹视网膜厚度与初诊比较均有差异(均P<0.05),干预后6 mo与12 mo比较均有差异(均P<0.05)。三组患儿干预前后其余黄斑区视网膜厚度比较均无差异(均P>0.05)。结论:0.01%阿托品滴眼液防控近视作用优于翻转拍视力训练及七叶洋地黄双苷滴眼液。应用0.01%阿托品滴眼液及接受翻转拍训练可延缓隐匿性近视的进展。