Formation and control of the surface defect in hypo-peritectic steel during continuous casting:A review

Hypo-peritectic steels are widely used in various industrial fields because of their high strength,high toughness,high processability,high weldability,and low material cost.However,surface defects are liable to occur during continuous casting,which includes depression,longitudinal cracks,deep oscillation marks,and severe level fluctuation with slag entrapment.The high-efficiency production of hypo-peritectic steels by continuous casting is still a great challenge due to the limited understanding of the mechanism of peritectic solidification.This work reviews the definition and classification of hypo-peritectic steels and introduces the formation tendency of common surface defects related to peritectic solidification.New achievements in the mechanism of peritectic reaction and transformation have been listed.Finally,countermeasures to avoiding surface defects of hypo-peritectic steels duiring continuous casting are summarized.Enlightening certain points in the continuous casting of hypo-peritectic steels and the development of new techniques to overcome the present problems will be a great aid to researchers.

Three-dimensional stereotactic surface projection in the statistical analysis of single photon emission computed tomography data for distinguishing between Alzheimer's disease and depression

AIM To evaluate usefulness of single photon emission computed tomography(SPECT) with three-dimensional stereotactic surface projection(3D-SSP) in distinguishing between Alzheimer's disease(AD) and depression.METHODS We studied 43 patients who presented with both depressive symptoms and memory disturbance. Each subject was evaluated using the following:(1) the Minimal Mental State Examination;(2) the Hamilton Rating Scale for Depression;(3) Clinical Global Impression-Severity scale(CGI-S); and(4) SPECT imaging with 3D-SSP.RESULTS The MMSE scores correlated significantly with the maximum Z-scores of AD-associated regions. CGI-S scores correlated significantly with the maximum Z-scores of depression-associated regions. Factor analysis identified three significant factors. Of these, Factor 1 could be interpreted as favouring a tendency for AD, Factor 2 as favouring a tendency for pseudo-dementia, and Factor 3 as favouring a depressive tendency.CONCLUSION We investigated whether these patients could be categorized as types: Type A(true AD), Type B(pseudodementia), Type C(occult AD), and Type D(true depression). The factor scores in factor analysis supported the validity of this classification. Our results suggest that SPECT with 3D-SSP is highly useful for distinguishing between depression and depressed mood in the early stage of AD.

Mechanism of Surface Depression on Foam Glass

The mechanism of the surface depression of the foam glass was studied. A method of powder sintering with plate glass as the raw material and carbon black as the foaming agent was adopted to investigate the influences of foaming temperature, soaking time, moisture content in the release agent, and flame preheating temperature on the surface depression of a foam glass blank. The results indicated that insufficient cooling rate and rapid foaming process that could not react synergistically with the surface tension and viscosity of the glass melt aroused the mismatching between the glass melt and the expansion or contraction of gas, resulting in upper surface depression of foam glass. Besides, the batch carbon black at high temperature reacted with residual water in advance to generate large amounts of gas and form the air space which could expand inside, leading to lower surface depression of foam glass.

A STRATIGRAPHIC UNCONFORMITY SURFACE BETWEEN THE NEOGENE AND THE PALEOGENE IN THE JIYANG DEPRESSION,BOHAI BAY BASIN, EASTERN CHINA:GEOLOGIC CHARACTERISTICS, FORMATIONPROCESS AND GEODYNAMIC ORIGIN

Regional stratigraphic unconformity surfaces are commonly observed in both orogenic beltsand sedimentary basins. They have superficially simple features, but in fact contain abundant geo-logic and geodynamic in formation on basin evolution, which was rarely systematically studied.Based on the elaborate research on geologic characteristics of the stratigraphic unconformity sur-face between the Neogene and the Paleogene in the Jiyang depression, Bohai Bay basin, EasternChina, this paper reconstructed its formation process and paleotopography in the late Oligocene. ltis the most interesting that this stratigraphic uncon formity surface represents the transiton of theJiyang depression evolution from rifting extension to thermal down-warping and also implies an u-plift process during the transition. This paper thought it worthy to study the origin of thisstratigraphic uncohformity surface and its relation to the stage transition of basin evolution. ThenpossibIe influences of regional stress field and deep dynamic process variations on the stratigraphicunconforrnity surface formation were anaIyzed. The stratigraphic unconformity surface betweenthe Neogene and the Paleogene in the Jiyang depression should be the direct result of extremestretching of llthosphere and diapirism of hot upper mantle, which can also possibly explain the co-incidence of the unconformity surface formation with the stage transition of basin evolution. Fur-thermore. the influences of the stratigraphic unconformity surface formation on oil and gas accu-mulation, the erosion amount calculation, and the elaborate time structure recorded by thestratigraphic unconformity surface were discussed.

The interaction between multiple bubbles and the free surface

The flow is assumed to be potential, and a boundary integral method is used to solve the Laplace equation for the velocity potential to investigate the shape and the position of the bubble. A 3D code to study the bubble dynamics is developed, and the calculation results agree well with the experimental data. Numerical analyses are carried out for the interaction between multiple bubbles near the free surface including in-phase and out-of-phase bubbles. The calculation result shows that the bubble period increases with the decrease of the distance between bubble centres because of the depression effect between multiple bubbles. The depression has no relationship with the free surface and it is more apparent for out-of-phase bubbles. There are great differences in dynamic behaviour between the in-phase bubbles and the out-of-phase bubbles due to the depression effect. Furthermore, the interaction among eight bubbles is simulated with a three-dlmensional model, and the evolving process and the relevant physical phenomena are presented. These phenomena can give a reference to the future work on the power of bubbles induced by multiple charges exploding simultaneously or continuously.

Application of active-source surface waves in urban underground space detection: A case study of Rongcheng County, Hebei, China

Active-source surface wave exploration is advantageous because it has high imaging accuracy,is not affected by high-speed layers,and has a low cost;thus,it has unique advantages for investigating shallow surface structures.For the development and utilization of urban underground space,two parameters in the shallow surface are important,namely,the shear wave velocity(V_(S))and the predominant period of the site,which determine the elevation and aseismic grade of the building design.The traditional method is mainly to obtain the two above-mentioned parameters through testing and measuring drilling samples.However,this method is extremely expensive and time consuming.Therefore,in this research,we used the multichannel surface wave acquisition method to extract the fundamental dispersion curve of single-shot data by using the phase shift method and obtain the V_(S) characteristics in the uppermost 40 m by inversion.We arrived at the following two conclusions based on the V_(S) profile.First,the study area can be roughly divided into five layers,among which the layers 0−8 m,14−20 m,and 20−30 m are low-velocity layers,corresponding to miscellaneous fill,a water-bearing sand layer,and a sand layer;therefore,the V_(S) is relatively low.In contrast,the layers at 8−14 m and 30−40 m are high-velocity layers that are mainly composed of clay,with a relatively better compactness and relatively high V_(S) values.In addition,a low-speed anomaly appears abruptly in the high-speed area at 20−40 m.This anomaly,when combined with geological data,suggests that it is an ancient river channel.Second,from the V_(S) value,the V_(Se)(equivalent shear wave velocity)was calculated.The construction site soil was categorized as class III,with good conditions for engineering geology.In addition,we calculated the predominant period of the site to be 0.56-0.77 s based on the V_(S).Therefore,in the overall structural design of the foundation engineering,the natural vibration period of the structure should be strictly controlled to avoid the predominant period of the site.

Gravity Wave Generated by Initial Axisymmetric Disturbance at the Surface of an Ice‑covered Ocean with Porous Bed

This paper is concerned with the generation of gravity waves due to prescribed initial axisymmetric disturbances created at the surface of an ice sheet covering the ocean with a porous bottom.The ice cover is modeled as a thin elastic plate,and the bottom porosity is described by a real parameter.Using linear theory,the problem is formulated as an initial value problem for the velocity potential describing the motion.In the mathematical analysis,the Laplace and Hankel transform techniques have been used to obtain the depression of the ice-covered surface in the form of a multiple infnite integral.This integral is evaluated asymptotically by the method of stationary phase twice for a long time and a large distance from the origin.Simple numerical computations are performed to illustrate the efect of the ice-covered surface and bottom porosity on the surface elevation,phase velocity,and group velocity of the surface gravity waves.Mainly the far-feld behavior of the progressive waves is observed in two diferent cases,namely initial depression and an impulse concentrated at the origin.From graphical representations,it is clearly visible that the presence of ice cover and a porous bottom decreases the wave amplitude.Due to the porous bottom,the amplitude of phase velocity decreases,whereas the amplitude of group velocity increases.

Cauchy-Poisson Problem for a Two-layer Fluid with an Inertial Surface

This paper is concerned with the generation of waves due to initial disturbances at the upper surface of a two-layer fluid, as the upper layer is covered by an inertial surface and the lower layer extends infinitely downwards. The inertial surface is composed of thin but uniform distribution of non-interacting material. In the mathematical analysis, the Fourier and Laplace transform techniques have been utilized to obtain the depressions of the inertial surface and the interface in the form of infinite integrals. For initial disturbances concentrated at a point, the inertial surface depression and the interface depression are evaluated asymptotically for large time and distance by using the method of stationary phase. They are also depicted graphically for two types of initial disturbances and appropriate conclusions are made.

页岩核磁共振横向弛豫时间与孔径分布量化关系及应用

核磁共振横向弛豫时间(T2)常用于表征页岩的全孔径分布特征。为确定T2谱与页岩孔径的量化关系,选取济阳坳陷沙河街组7块页岩样品进行低温氮吸附、核磁共振实验。利用T2几何平均值和孔隙比表面积、孔隙体积之间的关系式,获得T2谱计算孔径分布的关键参数——表面弛豫率。7块页岩样品的表面弛豫率为1.52~3.06 nm/ms,平均值为2.53 nm/ms。由表面弛豫率计算的孔径分布结果与低温氮吸附的NLDFT模型计算结果相似度高,证实了页岩表面弛豫率确定方法和取值的合理性。利用上述方法确定了济阳坳陷典型页岩薄层的孔径分布,结合储层物性和地球化学分析结果,认为页岩中泥质薄层主要起到生-储作用,而纤维状方解石薄层、粉晶方解石薄层和长英质薄层则可以作为储-渗通道。在研究页岩油微观富集、流动机制及评价页岩油“甜点”时,需细化分析不同薄层的孔径分布特征及其生-储-渗作用。

新型矿用EMI降尘剂对煤尘的润湿特性研究

随着矿井机械化开采程度的提高,煤尘产生量也随之增大。针对煤矿井下作业环境中的粉尘污染日益严重的问题,通过测定含不同质量分数绿色高效生物降尘剂(EMI)溶液的表面张力,并以不同粒径煤尘与EMI溶液的接触角、煤尘润湿速度、煤尘吸湿量及保水性为指标,研究了不同质量分数的EMI溶液对不同粒径煤尘的润湿效果。实验结果表明:随着溶液中EMI降尘剂的质量分数增大,煤尘的接触角逐渐减小,煤尘完全沉降所需时间逐渐下降,吸湿量逐渐增大,保水性逐渐增强,且失水后煤样的板结性较大。通过分析得出EMI润湿煤尘的作用机理:降低水的表面张力;增加溶液润湿性;减少水分流失;提高溶液的抗蒸发性。

NaClO和KMnO4协同氧化对黄铜矿与黄铁矿浮选分离的影响及其机理

通过浮选试验、吸附实验、红外光谱和XPS分析等研究了NaClO和KMnO_(4)单独使用以及组合使用对黄铜矿和黄铁矿浮选分离的影响。结果表明,在NaClO与KMnO_(4)质量比10∶1、总质量浓度70 mg/L,矿浆pH=10,氧化时间3 min条件下,黄铜矿回收率达到92%以上,黄铁矿回收率低于8%,较好地实现了黄铜矿与黄铁矿的选择性分离。红外光谱和XPS分析结果表明,组合药剂明显改变了黄铁矿的表面性质,使其表面氧化为氧化铁、氢氧化铁和硫酸铁等亲水性物质,并阻碍捕收剂的吸附,从而降低黄铁矿的可浮性。黄铜矿表面在一定处理条件下对NaClO和KMnO_(4)保持温和惰性,因此黄铜矿表面吸附的黄药量远大于黄铁矿表面,这有利于黄铜矿与黄铁矿的浮选分离。

一般依恋、父母依恋与青少年抑郁和问题行为的关系

依据依恋系统的层级模型,采用二次多项式回归与响应面分析方法,探究一般依恋与父母依恋如何共同作用于青少年的抑郁与问题行为。研究招募488名初高中生,采用关系结构问卷等工具进行相关变量测查。结果表明,一般依恋与父母依恋存在显著正相关;青少年一般依恋与父母依恋能负向预测抑郁和问题行为水平,且存在一般依恋与父母依恋的交互作用;在对问题行为的预测上,存在一般依恋与母亲依恋的匹配效应。

大径厚比导管全位置焊接分区段组织结构与力学性能分析

【目的】在大径厚比不锈钢导管全位置焊接工艺中,研究分区段焊缝的组织结构与力学性能的差异。【方法】对外径为52 mm、厚度为0.8 mm的不锈钢管材进行脉冲钨极氩弧(Tungsten inert gas,TIG)全位置焊接试验,采用分区段设置工艺参数的控制方法优化焊缝成形。通过分区段方法对焊缝宏观形貌、微观组织和抗拉强度进行分析,评定全位置焊接过程中熔池综合受力情况差异对焊缝宏观成形和力学性能的影响。【结果】结果表明,采用的分区段设置参数的焊接方法能够有效适用于大径厚比管材环缝焊接,得到的焊缝内外表面光泽度良好,无需进行打磨处理;焊缝内外表面凹陷均小于0.1 mm,分区段焊缝熔宽均匀度良好,上熔宽与下熔宽之比均在1.1左右;焊缝中心微观组织由细小柱状奥氏体枝晶和枝晶间铁素体组成,热影响区窄,在半熔化区域与柱状晶之间存在狭长的细小晶粒带;各区段抗拉强度差别较小,平均值为534 MPa,达到I级焊缝要求。【结论】分区段设置工艺参数对薄壁不锈钢管进行全位置焊接,外观成形和内部质量能够达到I级焊缝要求,可满足航天行业增压输送系统导管的生产要求。

疏干排水对临近铁路安全性影响研究

某矿开拓过程中需充分考虑对临近铁路的影响,分别从开拓系统疏干形成的降水漏斗影响范围及对地表和铁路的影响进行分析,通过库萨金公式计算降水漏斗影响半径,同时利用渗流分析法求解地表下沉位移,在此基础上利用FLAC3D分析疏干排水形成的降水漏斗对开拓巷道、地表及铁路稳定性的影响。得到如下结论:理论计算的矿区最大降水漏斗影响半径为1323.14 m,矿区临近铁路均在最大降水漏斗范围内,铁路线附近地表沉降为4.61 mm;-270、-230、-170 m和-120 m四个水平开拓巷道的孔隙水压下降最大值分别为2.74、2.34、1.73 MPa和1.21 MPa,最大沉降分别为0.53、0.74、1.01 mm和1.15 mm;降水漏斗引起地表最大沉降为1.62 mm,铁路干线上最大沉降为1.53 mm,均远小于Ⅰ级建、构筑物位移与变形的允许倾斜i=3 mm/m。理论计算和数值模拟结果表明,矿区开拓系统疏干排水形成的降水漏斗对开拓巷道、地表和铁路均无显著的影响。

基于网络药理-分子对接-SPR技术研究甘麦大枣汤联合百合知母汤治疗抑郁症的分子机制

目的通过网络药理学探析甘麦大枣汤联合百合知母汤的活性成分及治疗抑郁症的潜在靶点,并通过分子对接、表面等离子共振(SPR)实验、热迁移实验对主要活性成分-关键靶点相互作用进行验证。方法运用中药系统药理学技术平台(TCMSP)、草本成分靶点平台(HIT)、中药分子机制生物信息学分析工具数据库(BATMAN-TCM)、中医百科全书数据库(ETCM)筛选甘麦大枣汤联合百合知母汤的有效成分。运用TCMSP数据库、比较毒理基因组学数据库(CTD)、PHARMAPPER药物靶点数据库获得甘麦大枣汤联合百合知母汤的潜在作用靶点,运用人类基因数据库(GeneCards)和基因表达数据库(GEO)获得抑郁症相关靶点,与上述药物作用靶点取交集后得到潜在治疗抑郁症靶点。运用String数据库构建靶点蛋白-蛋白相互作用(PPI)网络,运用DAVID数据库和京都基因与基因组百科全书(KEGG)数据库进行基因本体(GO)和KEGG富集分析,运用Cytoscape软件构建相应网络,筛选甘麦大枣汤联合百合知母汤抗抑郁的关键靶点和相应的活性成分。运用Discovery studio软件进行分子对接,运用SPR技术检测活性成分与靶点结合活性,运用热迁移实验检测主要活性成分与靶点的结合作用。结果经药物吸收-分配-代谢-排泄-毒性数据库(ADMET)筛选后获得甘麦大枣汤联合百合知母汤的有效成分160个,与抑郁症相关靶点、抑郁患者差异表达基因取交集后获得潜在抗抑郁靶点763个。经PPI网络分析、GO及KEGG富集分析发现,丝裂原活化蛋白激酶(MAPK)信号通路等10条信号转导通路可能发挥重要作用,其中MAPK14处于关键位置。分子对接和SPR实验结果显示,刺芒柄花素(formononetin)、甘草查尔酮A(licochalcone A)和维斯体素(vestitol)为甘麦大枣汤联合百合知母汤的主要活性成分,可与MAPK14蛋白结合,亲和力分别为2.36μmol/L、26.01μmol/L、11.30μmol/L。热迁移实验显示这3个成分与MAPK14结合后可显著提高MAPK14的热稳定性,表明这3个成分与MAPK14能发生相互作用。结论MAPK14是治疗抑郁症的潜在靶点,甘麦大枣汤联合百合知母汤通过其中3种活性成分与MAPK14结合,首次从活性分子直接作用靶点角度解释了甘麦大枣汤联合百合知母汤治疗抑郁的分子机制。

连铸坯窄面凹陷缺陷产生原因分析及预防

本文针对连铸坯窄面纵向凹陷缺陷,借助连铸坯缺陷宏观形貌分析、连铸坯低倍酸洗分析、金相组织分析和化学成分检测等手段,结合连铸坯生产工艺,分析了连铸坯窄面纵向凹陷缺陷产生原因。确定了连铸结晶器窄面冷却水量不合理造成的铸坯初生坯壳冷却不均,结晶器锥度过大对结晶器坯壳产生挤压是缺陷产生的主要原因。通过采取结晶器冷却水量优化、结晶器窄面锥度调整控制及保护渣性能优化等措施,有效提高了连铸板坯表面质量,杜绝了连铸坯窄面纵向凹陷缺陷发生。

A Preliminary Analysis of Relations Between Tectonic Deformation of Sedimentary Cover and Basement in Kuqa Depression

Study of seismic activity in the Kuqa area enables us to infer some possible active faults in basement from the epicentral distribution on different profiles. The relations between active faults in the basement and surface structures are analyzed and the difference between sedimentary cover and basement in their deformation characteristics and the genesis are discussed. The following conclusions have been drawn: (1) the epicentral distribution indicates that, the east Qiulitag and south and north Qiulitag deep faults in the basement correspond to the east and west Qiulitag anticlines, respectively. Moreover, deep faults also exist beneath the Yiqiklik and Yaken anticlines. It indicates that the formation of surface structures is controlled by deep structures; (2) A NE-trending strike-slip fault develops along the line from the western termination of Yiqiklik structure to Dongqiu Well 5 and a NW-trending active fault on the western side of Baicheng. The two active faults across the tectonic strike are the main causes for tectonic segmentation of the Kuqa depression and possibly the cause for the middle segment (Kuqa-Baicheng) of the depression to be more shortened than both its eastern and western terminations; (3) The difference between the sedimentary cover and basement in their deformation characteristics depends mainly on the different properties of media between them. The lithospheric strength of the basement in the basin is fairly high, which determines the basement deformation to be mainly of brittle fracture——seismic activity. While the strength of sedimentary cover is low, where there exist weak thin layers, such as coal and gyps. Under the effect of strong tectonic compression, the sedimentary rocks may undergo strong viscous or plastic flow deformation; meanwhile, an aseismic detachment may take place along the weak layers.

百合地黄汤多糖提取工艺优化及抗焦虑抑郁药效评价

目的 优化百合地黄汤多糖提取工艺并初步评价其抗焦虑抑郁药效。方法 在Plackett-Burman实验基础上,以多糖得率与多糖含量的综合评分为评价指标,提取时间、加水量、醇沉浓度为考察因素,结合Box-Behnken响应面法优化百合地黄汤多糖提取工艺并验证。将40只ICR小鼠分为对照组、文法拉辛组[阳性对照,13.5 mg/(kg·d)]和百合地黄汤多糖高、低剂量组[5.28、2.64g/(kg·d),以生药量计],每组10只(雌雄各半)。药物组小鼠灌胃相应药液,对照组小鼠灌胃水10 mL/kg,每天1次,连续7 d。采用高架十字迷宫实验、旷场实验、强迫游泳实验、悬尾实验评价最优工艺所制提取物对小鼠焦虑抑郁样行为的改善情况,并采用酶联免疫吸附测定法检测其对小鼠脑组织中神经递质水平的影响。结果 百合地黄汤多糖的最优提取工艺为加25倍量水,提取1.5 h,醇沉浓度70%。3次验证实验的多糖得率、多糖含量平均值分别为33.10%、0.62 mg/mg,与预测值(36.14%、0.65 mg/mg)的相对偏差分别为8.40%、4.62%(RSD<2%,n=3)。所得百合地黄汤多糖提取物能显著增加小鼠进入开放臂的次数比例及开放臂停留时间比例、自主活动总距离及中心区域活动距离,并显著缩短其强迫游泳实验、悬尾实验不动时间(P<0.05或P<0.01);可显著升高小鼠脑组织中5-羟色胺、去甲肾上腺素(百合地黄汤多糖低剂量组除外)、γ氨基丁酸水平,并显著降低谷氨酸(百合地黄汤多糖低剂量组除外)水平(P<0.05或P<0.01)。结论 优化的百合地黄汤多糖提取工艺稳定、可行;所得多糖提取物具有明显的体内抗焦虑抑郁作用。

Use of brGDGTs in surface geochemical exploration for petroleum —A case study of oil and gas fields in the Jiyang depression

Branched glycerol dialkyl glycerol tetraethers(brGDGTs),likely produced by bacteria in soil and peat,are widely distributed,easily detected,newly adopted biomarker compounds.In this study,brGDGTs were used to explore the relationship between the absolute abundance of brGDGTs and the distribution of oil and gas fields in the Duoshiqiao area of the Jiyang depression.The results showed that the concentrations at the Xiakou fault and in the oil and gas fields were obviously higher than those in the contrast areas.The clear relationship among the concentration of brGDGTs,the distribution of oil and gas fields,and the acidolysis hydrocarbon(ethane)indicates that the concentration effectively responds to hydrocarbon seeps from the oil and gas field below.brGDGTs may become some of the most important indicators in surface geochemical prospecting for oil and gas.

齐齐哈尔两次暴雨天气过程对比分析

利用多种资料对发生在齐齐哈尔的两次暴雨进行对比分析。结果表明:(1)这两次暴雨都发生在副热带高压位置最北期间,都是副热带高压、高空冷涡和地面低压大尺度环流造成的;“8.3”暴雨比“8.6”暴雨副热带高压位置更偏西,地面低压中心值更低。(2)“8.6”暴雨过程齐齐哈尔地区水汽输送量更大、辐合更强、低层上升运动更明显、造成暴雨范围更大。(3)“8.3”暴雨雷达回波强度更强,55 dBz以上强回波排列紧密,呈现带状;“8.6”暴雨雷达回波,甘南县境内存在“列车效应”,且径向速度场零速度线呈“S”型结构,有明显的暖平流。