Experimental study on the movement of oil spill under freeze-thaw action

Oil leakages cause environmental pollution,economic losses,and even engineering safety accidents.In cold regions,researchers urgently investigate the movement of oil spill in soils exposed to freeze-thaw cycles.In this study,a series of laboratory model experiments were carried out on the migration of oil leakage under freeze-thaw action,and the distributions of the soil temperature,unfrozen water content,and displacement were analyzed.The results showed that under freeze-thaw action,liquid water in soils migrated to the freezing front and accumulated.After the pipe cracked,oil pollutants first gathered at one side of the leak hole,and then moved around.The pipe wall temperature affected the soil temperature field,and the thermal influence range below and transverse the pipe wall(35–40 cm)was larger than that above the pipe wall(8 cm)owing to the soil surface temperature.The leaked oil's temperature would make the temperature of the surrounding soil rise.Oil would inhibit the cooling of the soils.Besides,oil migration was significantly affected by the gravity and water flow patterns.The freeze-thaw action would affect the migration of the oil,which was mainly manifested as inhibiting the diffusion and movement of oil when soils were frozen.Unfrozen water transport caused by freeze-thaw cycles would also inhibit oil migration.The research results would provide a scientific reference for understanding the relationship between the movement of oil pollutants,water,and soil temperature,and for establishing a waterheat-mass transport model in frozen soils.

Inaccuracy of Self-reported Low Sodium Diet among Chinese: Findings from Baseline Survey for Shandong & Ministry of Health Action on Salt and Hypertension(SMASH) Project

This study was aimed to evaluate the agreement between the self-reported sodium intake level and 24-h urine sodium excretion level in Chinese. The 24-h urine collection was conducted among 2112 adults aged 18-69 years randomly selected in Shandong Province, China. The subjects were asked whether their sodium intake was low, moderate, or high. The weighted kappa statistics was calculated to assess the agreement between 24-h urine sodium excretion level and self-reported sodium intake level. One third of the subjects reported low sodium intake level. About 70% of the subjects had mean 24-h sodium excretion 〉9 g/d, but reported low or moderate sodium intake.

冻融和盐作用对糯米粉的结构和糊化特性的影响

糯米浆是我国古代应用最广泛的建筑胶凝材料,可显著提高三合土和灰浆的强度特性、抗渗特性和粘结特性.挖掘糯米浆的科学价值,对于传统技术的科学利用,特别是对古建筑的修复具有十分重要的意义.文中用石油醚对糯米粉进行脱脂,采用双波长法对糯米粉中的直链淀粉和支链淀粉进行测定,用FT-IR,XRD,TG/DTG和SEM分析了糯米粉脱脂前后的结构和形貌,同时用XRD和SEM分析了冻融循环、Na 2SO 4加入对糯米淀粉结构、晶型和形貌的改变,用Brabender粘度仪研究了不同条件下的糊化特性.结果表明,糯米粉中直链淀粉和支链淀粉的含量分别为9.16%和78.56%,糯米粉和脱脂糯米粉的糊化温度基本相同,但峰值粘度、崩解值和回升值下降.冻融循环不会改变糯米粉中淀粉颗粒的结构和晶型,但峰值粘度、谷值粘度、终值粘度、崩解值和回升值均有降低趋势;加入4%的Na 2SO 4后,会使糊化温度升高,崩解值升高,回升值下降.本研究对糯米粉的科学认知具有重要的意义,期望为针对性地提高糯米浆的胶凝品质提供理论参考.

油菜素内酯调控植物耐盐机理研究进展

油菜素内酯(brassinosteroid,BR)作为新型、高效的植物激素,广泛参与植物的各种生理过程,可以缓解多种非生物胁迫。阐述了BR处理缓解盐胁迫的生物学功能,总结了拟南芥、农作物水稻以及多种园艺植物的BR信号通路,并通过介绍BR的耐盐机理,进一步分析了植物遭受盐胁迫时的应答信号转导通路,旨在为加强BR在提高植物耐盐方面的应用提供理论依据。

冻融循环作用下粉砂质硫酸盐渍土变形特性研究

【目的】为探究南疆地区粉砂质硫酸盐渍土的变形特性,【方法】在封闭系统条件下对粉砂土进行冻融循环试验,利用扫描电镜对土体结构进行表征分析。【结果】结果显示:粉砂质硫酸盐渍土硫酸钠含量为0和1.0%时变形以融沉为主,5次循环后变形量分别为-1.30 mm、-1.02 mm;硫酸钠含量为2.0%、5.0%、8.0%时变形表现为盐胀-冻胀变形,5次循环后变形量分别为2.46 mm、8.53 mm、3.43 mm。【结论】结果表明:粉砂质硫酸盐渍土在冻融循环作用下温度和硫酸钠含量是影响土体发生冻融变形的主要因素。在低温区间土体的变形随温度的降低表现为盐胀-冻胀,在升温过程中土体先后出现冰融和盐溶变形;土体的最终变形量与硫酸钠含量的变化表现为先增后减,当硫酸钠含量为5.0%时,土体的盐-冻胀率达到最大为2.5%。运用扫描电镜可发现粉砂质硫酸盐渍土经冻融循环后在自重作用下会产生沉降,内部盐分重结晶是抑制沉降甚至造成土体膨胀的主要原因。

非饱和盐渍黏土物理化学作用的应力依赖特性

为了揭示物理化学作用对含盐溶液非饱和黏土压缩行为的影响及其与应力水平的依赖特性,对孔隙含蒸馏水、氯化钠和硫酸钠溶液及控制基质吸力条件下的试样进行了一维压缩试验。然后,根据试验结果测定了不同条件下黏土的压缩指数、次固结系数和屈服应力,并标定了它们随基质吸力和渗透吸力的变化规律。此外,对不同基质吸力和渗透吸力下非饱和盐渍黏土主、次固结行为展开了深入分析,明确了非饱和盐渍黏土物理化学作用的应力依赖特征,并对非饱和盐渍黏土的LC屈服行为进行了探索。结果表明:不同物理化学力下非饱和盐渍黏土的次固结系数与压缩指数的比值C_(a)/C_(c)以及屈服应力可以使用基质吸力和渗透吸力来统一描述;由塑性加载区压缩曲线斜率以及特征参量、C_(a)/C_(c)与竖向应力的相关性指出非饱和盐渍黏土物理化学作用与应力水平息息相关;此外,化学-水力-力学耦合作用下非饱和盐渍黏土的LC屈服曲线是由MLC屈服曲线和OLC屈服曲线组成的一条光滑曲线。

The Influence of CO_(2) Cured Manganese Slag on the Performance and Mechanical Properties of Ultra-High Performance Concrete

The presence of toxic elements in manganese slag(MSG)poses a threat to the environment due to potential pollution.Utilizing CO_(2) curing on MS offers a promising approach to immobilize toxic substances within this material,thereby mitigating their release into the natural surroundings.This study investigates the impact of CO_(2) cured MS on various rheological parameters,including slump flow,plastic viscosity(η),and yield shear stress(τ).Additionally,it assesses flexural and compressive strengths(f_(t) and f_(cu)),drying shrinkage rates(DSR),durability indicators(chloride ion migration coefficient(CMC),carbonization depth(CD)),and the leaching behavior of heavy metal elements.Microscopic examination via scanning electron microscopy(SEM)is employed to elucidate the underlying mechanisms.The results indicate that CO_(2) curing significantly enhances the slump flow of ultra-high performance concrete(UHPC)by up to 51.2%.Moreover,it reduces UHPC’sηandτby rates ranging from 0%to 52.7%and 0%to 40.2%,respectively.The DSR exhibits a linear increase corresponding to the mass ratio of CO_(2) cured MS.Furthermore,CO_(2) curing enhances both f_(t) and f_(cu) of UHPC by up to 28.7%and 17.6%,respectively.The electrical resistance is also improved,showing an increase of up to 53.7%.The relationship between mechanical strengths and electrical resistance follows a cubic relationship.The CO_(2) cured MS demonstrates a notable decrease in the CMC and CD by rates ranging from 0%to 52.6%and 0%to 26.1%,respectively.The reductions of leached chromium(Cr)and manganese(Mn)are up to 576.3%and 1312.7%,respectively.Overall,CO_(2) curing also enhances the compactness of UHPC,thereby demonstrating its potential to improve both mechanical and durability properties.

基于网络药理学探究盐敷方治疗膝骨关节炎的作用机制

目的:探讨盐敷方组方治疗膝骨关节炎可能的作用机制。方法:运用中药系统药理学数据库与分析平台(TCMSP)筛选盐敷方的活性成分及其对应的靶点基因,并用UniProt数据库对基因名进行校正,通过Disgenet和Drugbank数据库获取膝骨关节炎的疾病靶点,并得到盐敷方与膝骨关节炎的共同靶点,利用Cytoscape3.10.0软件绘制“盐敷方成分靶点网络图”,利用String数据库构建盐敷方与膝骨关节炎共同靶点PPI网络,利用Cytoscape数据库进行GO及KEGG富集分析。结果:(1)共筛选出盐敷方活性成分86个及活性成分作用靶点255个;(2)与疾病的交集靶点共有51个,核心靶点为TNF、IL-6、IL-1β、ALB、PTGS2等;(3)GO分析结果共涉及882个生物学过程(BP)、26种细胞成分(CC)、78个分子功能(MF);(4)KEGG分析结果显示,盐敷方治疗膝骨关节炎的信号通路主要有IL-17、肿瘤坏死因子、类风湿关节炎、核因子κB等信号通路。结论:盐敷方可通过下调细胞因子表达、抑制炎症反应、减慢软骨降解退变等途径来延缓膝骨关节炎的发展。

热-盐作用下水稳碎石强度变化规律及破坏特征研究

水泥稳定碎石材料在热-盐作用下发生物理和化学侵蚀反应,使得试件强度变化规律和破坏特征发生变化。文章采用无侧限抗压强度试验和数码相机图像采集技术,分析了硫酸钠含量、成型温度、水泥含量对水稳碎石材料强度变化规律和试件破坏特征的影响。结果表明:随着硫酸钠含量增加,无侧限抗压强度先增大后减小,峰值点在2.5%,试件破坏形式由龟裂破坏转变为主裂缝破坏,再转变为多裂缝破坏;无侧限抗压强度随着成型温度、水泥含量的升高逐渐增大,且试件由龟裂破坏转变为主裂缝破坏;当试件强度强化,其破坏形式以主裂缝破坏为主;基于强度变化规律,采用最小二乘法和归一化法,建立了热-盐作用下水稳碎石无侧限抗压强度变化预测模型。

Application of annexation principle to the study of thermodynamic properties of ternary molten salts CaCl_2-MgC_2-NaCl

Based on the practical basis of measured activities and phase diagrams aswell as in the light of the mass action law. the model of inseparable cations and anions of moltensalts and mattes, and the annexation principle of two kinds of solutions in binary melts, thecalculating model of mass action concentrations of molten salts CaCl_2-MgCl_2-NaCl was formulated.The results of calculation not only agree with experimental values, but also obey the mass actionlaw, testifying that the model formulated can embody the structural characteristics of these ternarysalts, and that the model of inseparable cations and anions as well as the annexation principle oftwo kinds of solutions in binary melts are also applicable to these ternary salts.

Effects of freeze-thaw cycle and dry-wet alternation on slope stability

The typical loess on high slopes along the BaoLan High-speed Rail, China, was selected as the research object. The influence of the freeze-thaw cycle and dry-wet alternation on the shear-strength parameters of the unsaturated loess was investigated by laboratory experimental methods. Moreover, the temperature field, seepage field, and stability of slopes with different gradients were simulated under the effect of the freeze-thaw cycle and dry-wet alternation by using the geotechnical analysis software Geo-Studio. The research results showed(1) when the freeze-thaw cycle was repeated on the slope, with the frozen depth increasing, the melted depth did the same; besides, the closed loop of isotherms formed on the slope;(2) under the action of dry-wet circulation, the negative pore-water pressure and volumetric water content showed an upward tendency. However, owing to the different slope gradients, rainfall infiltration was not the same. As time went by, the differences of the negative pore-water pressure and volumetric water content between the slopes of different gradients continued to increase;(3) with the freeze-thaw cycle and dry-wet alternation increasing, the slope-safety factor decreased. Especially in the early period, the slope-safety factor changed remarkably. For slopes undergoing freeze-thaw action, the slope-safety factor was negatively correlated with the gradient. However, with regard to slopes undergoing dry-wet alternation, the result became more complex because the slope-safety factor was related to both seepage strength and slope grade. Accordingly, further research is needed to study the effect of seepage strength and slope grade on the stability of loess slopes.

Analyses on Temporal and Spatial Variation Characteristics of Erosion and Deposition in the Front Edge of Salt Marsh Wetland

Taking Yancheng Nature Reserve Salt Marsh as the research object,the remote sensing images from 2005 to 2020 were interpreted by using remote sensing and geographic information system technology.In this paper,the temporal and spatial variation characteristics of erosion and deposition in the front edge of salt marsh wetland were analyzed.The influence of sea level rise on the annual change of salt marsh area was analyzed.The characteristics of flow and sediment movement in salt marsh and the causes of erosion and deposition in front of salt marsh were analyzed.The results showed that:(1)During 2005-2007,the sea level was relatively low,and Spartina alterniflora in salt marsh expanded to the sea.Since 2007,the front edge of salt marsh wetland has coexisted with erosion and deposition.From 2008 to 2010,the front edge of salt marsh wetland once again showed a trend of comprehensive deposition to the sea side.From 2010 to 2012,the erosion of salt marsh wetland was serious.From 2012 to 2020,the front edge of salt marsh wetland in the range of 9 km south of Xinyang estuary was eroded.(2)The correlation analysis was carried out between the area of salt marsh wetland and sea level rise.Spartina alterniflora is easily affected by sea level change,owing to it having a low ecological niche.With the rise of sea level,the area of salt marsh has been decreasing since 2013.(3)In the front sea area of salt marsh wetland,the maximum velocity of the ebb and flood can reach the threshold velocity during the spring tide.The sediment starts to move at water depth of 10 m under wave actions.Owing to wave stirs up sediment and current transports the sediment,resuspended sediment causes the erosion of marsh-edge scarps.

冻融与氯盐侵蚀耦合作用下GO-RAC的耐久性能

通过混凝土抗冻性快冻法试验,研究了氧化石墨烯再生粗骨料混凝土(GO-RAC)在冻融循环与氯盐侵蚀耦合作用下的耐久性能,测试分析了GO-RAC的相对动弹性模量、质量损失率、抗压强度及氯离子侵蚀情况.结果表明:冻融循环与氯盐侵蚀的耦合作用加速了再生粗骨料混凝土(RAC)的劣化损伤,经历72次冻融循环后不同GO掺量GO-RAC的相对动弹性模量均降至其初始值的60%以下,宏观劣化程度较普通RAC有不同程度的降低;由于耦合初期侵蚀产物的填充致密效应,GO-RAC的抗压强度呈现先增大后减小的趋势;GO-RAC在冻融循环与氯盐侵蚀耦合作用下的Cl-分布符合Fick第二定律,表面的Cl-质量比随着耦合次数的增加呈指数形式增大,扩散系数随着耦合次数的增加先减小后增大.

高盐食品脱盐技术研究进展

食盐能够通过增加香气化合物的挥发性和影响唾液的润滑性能,提高食物的香气特征和口感。人体日常过量摄入食盐会引起高血压、心脏病等疾病,同时降低人体免疫力。针对高盐食品探索开发高效、稳定、经济的脱盐技术格外重要。文章综述了电渗析法、超声波等不同脱盐技术在食品领域的最新研究进展,为未来脱盐技术的开发研究提供了参考。

不同引气剂掺量早冻混凝土力学性能及孔结构分形特征

为研究水工混凝土材料在冻融循环与盐侵蚀耦合作用下构件性能演变规律,选取不同引气剂掺量(0、0.005%、0.01%)的早期受冻试件,置于质量分数为3.5%氯化钠+5%硫酸钠复合溶液内进行冻融循环试验,并基于核磁共振技术(NMR)—分形理论,构建混凝土孔体积分形维数与试件抗压强度间的耦联关系。结果表明,在混凝土材料中适量加入引气剂,可有效提高盐冻作用下构件的弹性模量、抗压强度等力学性能,并可改善孔结构,提高抗冻性;核磁共振测试的混凝土孔体积分形维数随着冻融循环次数的增加逐渐减小,表明引气剂的加入可改变初始状态下混凝土内部孔隙结构,且随着引气剂掺量的增加效果更为明显;结合分形理论建立的孔体积分形维数与抗压强度关联模型,发现分形维数DMAX与抗压强度的最佳函数关系近似指数函数,回归系数R2均大于0.85,拟合效果良好,可为混凝土结构的耐久性评估提供参考。

煤制天然气盐泥入气化炉掺烧的试验研究与分析探讨

为解决煤制天然气工艺过程中多效蒸发产生的盐泥的出路及利用问题,研究了盐泥入气化炉掺烧的可行性。采用干混法,将盐泥与块煤以0.3:100的质量比掺混入炉燃烧的试验。一周的试验结果表明,将盐泥均匀掺入气化炉内,变换入口合成气中甲烷体积分数提高了1个百分点以上,初步推断盐泥对气化炉内的甲烷化反应有催化作用;通过对渣水、煤气水、酚氨回收、污水处理系统相关指标分析,推断盐泥中的大部分盐以熔融态进入渣池系统,小部分盐可能随粗煤气带出,并随煤气水进入后续水系统。

克拉苏构造带博孜段古隆起及盐层对盐下冲断带的控制

克拉苏构造带是库车坳陷油气勘探的主要区带。以克拉苏构造带博孜段三维地震资料为基础,进行一体化建模,明确盐下冲断带构造变形差异及古隆起、盐层分布特征;基于物理模拟实验,分析古隆起、盐层对盐下冲断带的控制作用。结果表明:研究区薄盐层分层作用差,断裂数少,规模大,易传递至盐上层;厚盐层易形成盐背斜和盐焊接等构造,盐下层多排逆冲断裂向盆地内部传递;古隆起发育区北翼断裂表现为倾角小、水平断距大和沿斜坡滑脱等特征,古隆起不发育区断裂表现为倾角陡、断距大且断裂数多的特征。古隆起发育区易形成滑脱冲断和盐背斜构造,古隆起不发育区易形成阶梯冲断和盐焊接构造;古隆起与盐层的双重叠加是影响盐下冲断带复杂变形的主要因素,古隆起限制冲断体系变形空间,盐层缓冲应力传递,起调节作用。该结果对研究区下一步天然气勘探开发具有指导意义。

蜡油加氢热高分气/混合氢换热器腐蚀泄漏分析及防护

某公司蜡油加氢装置热高分气/混合氢换热器E5102在运行9 a后发生内漏,导致装置被迫紧急停工检修。检修结束后,对管束的腐蚀泄漏原因进行分析。通过宏观观察、管束测厚、元素分析及离子分析,结合工艺模拟计算、腐蚀机理分析和注水情况分析,认为管程NH_(4)Cl结盐导致垢下腐蚀、注水冲洗不彻底及注水方式不合理是引起换热器腐蚀泄漏的主要原因,并提出了改进措施及建议,希望对各企业预防加氢装置热高分气/混合氢换热器的腐蚀泄漏有一定帮助。

锂盐的临床应用进展

锂盐是精神疾病临床使用的所有药物中唯一一种非人造药物。锂盐用于临床已超过70年,现仍是双相障碍治疗的基础药物。锂盐在一定程度上改变了精神疾病的发展进程,但其治疗窗口较窄,治疗效果及安全性个体差异较大。本文就锂盐在临床应用中的相关问题及进展进行综述,以期为锂盐的临床应用提供参考。

基于可靠性的钢筋混凝土结构服役寿命研究

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