期刊文献+
共找到681篇文章
< 1 2 35 >
每页显示 20 50 100
激光原位Rb-Sr年代学定年原理、分析方法和地学应用
1
作者 于鹏岳 李超 +7 位作者 张基昊 章浩 任竑宇 左鹏飞 张苏坤 冯绍平 于皓丞 邱昆峰 《地学前缘》 北大核心 2026年第2期1-26,共26页
Rb-Sr放射性衰变广泛应用于岩石矿物年代学中,由于87 Sr同位素在质谱测量过程中会受到87 Rb的同质异位素的干扰,传统的方法只能通过化学前处理分离Rb和Sr元素,导致流程繁琐、实验周期较长、化学试剂消耗量大。此外,整体分析很难将不同... Rb-Sr放射性衰变广泛应用于岩石矿物年代学中,由于87 Sr同位素在质谱测量过程中会受到87 Rb的同质异位素的干扰,传统的方法只能通过化学前处理分离Rb和Sr元素,导致流程繁琐、实验周期较长、化学试剂消耗量大。此外,整体分析很难将不同期次、不同阶段矿物分离。近年来,激光剥蚀电感耦合等离子体串联质谱仪(laser ablation triple quadrupole inductively coupled plasma mass spectrometry,LA-ICP-MS/MS)的发展使原位Rb-Sr定年成为可能。LA-ICP-MS/MS在碰撞反应池中通入反应气体,通过测量Sr与N_(2)O或者SF_(6)等气体反应转换的SrO^(+)或SrF^(+),实现^(87)Rb和^(87)Sr的在线分离。原位Rb-Sr定年具有高效、低成本和原位分析等显著优势,被初步应用于地学研究中。本文介绍了原位Rb-Sr定年原理及方法,并梳理了该方法在微区原位定年中存在的元素分馏和基体效应等问题。回顾了近年来LA-ICP-MS/MS Rb-Sr年代学应用的研究进展,重点论述了该方法在沉积岩地层时代的直接厘定、基性岩浆岩和伟晶岩中精确定年、多期变质事件识别、断层活动的时代限定以及金矿成矿时代确定等方面的应用,包括在月球样品中原位Rb-Sr定年也呈现出较大的潜力。LA-ICP-MS/MS Rb-Sr定年技术的发展和应用,为未来地质年代学的研究提供了新思路,在地球科学研究中具有重要的发展前景。 展开更多
关键词 LA-ICP-MS/MS 原位Rb-Sr定年 三重四极杆质谱仪 基体效应激光微区分析 同位素定年
在线阅读 下载PDF
南秦岭老君庙金矿床载金含砷黄铁矿矿物学研究及其地质意义
2
作者 贾彬 张振 +5 位作者 魏立勇 吴欢欢 唐明锋 孟五一 田映天 王鑫 《西北地质》 北大核心 2026年第1期110-129,共20页
老君庙金矿床是南秦岭造山带中近年新发现的一个中型金矿床,位于公馆和青铜沟两个超大型汞锑矿床之间。金矿化主要赋存于上泥盆统西岔河组碎屑岩-碳酸盐岩中,受地层和构造控制,矿体沿EW向构造破碎带分布,在断裂交汇部位矿化相对集中。... 老君庙金矿床是南秦岭造山带中近年新发现的一个中型金矿床,位于公馆和青铜沟两个超大型汞锑矿床之间。金矿化主要赋存于上泥盆统西岔河组碎屑岩-碳酸盐岩中,受地层和构造控制,矿体沿EW向构造破碎带分布,在断裂交汇部位矿化相对集中。关于金在矿物中的分布规律及矿床类型尚缺乏系统研究。基于野外地质调查、矿相学观察、背散射电子图像(BSE)及电子探针分析(EPMA)等方法,查明老君庙金矿载金矿物的组分特征,判断Au的赋存状态,进而探讨矿床成因类型。研究结果显示,老君庙金矿成矿过程分为沉积成岩期、热液成矿期、表生氧化期等3个期次。热液成矿期的金矿化以微细浸染型为主,可划分为石英+含砷黄铁矿阶段(Ⅰ);石英+含砷黄铁矿+毒砂+闪锌矿阶段(Ⅱ)和石英+方解石阶段(Ⅲ)等3个成矿阶段。含砷黄铁矿和毒砂都是载金矿物,但黄铁矿是主要的载金矿物,沉积成岩期黄铁矿(Py1、Py2)和热液成矿期黄铁矿(Py3、Py4)均含金,热液成矿期黄铁矿含金性明显优于沉积成岩期黄铁矿,且Au、As具有正相关关系。金主要以不可见金形式存在,沉积成岩期黄铁矿中(Py1、Py2)Au主要以纳米金粒(Au^(0))形式赋存;而热液成矿期黄铁矿(Py3、Py4)和毒砂(Apy)中的金以晶格金(Au^(+))的形式赋存。老君庙金矿床的地质特征、成矿地质条件及金的赋存状态等与典型的卡林型金矿床相似,与中国各成因类型金矿的δFe-δS、δFe/δS-As、(Fe+S)-As体系对比,成矿期黄铁矿均落在在卡林型金矿床区域内,其成因类型应归属于卡林型金矿床。 展开更多
关键词 南秦岭 老君庙金矿 金的赋存状态 电子探针 载金硫化物 卡林型金矿
在线阅读 下载PDF
Effect of Beam Current and Diameter on Electron Probe Microanalysis of Carbonate Minerals 被引量:7
3
作者 Xing Zhang Shuiyuan Yang +3 位作者 He Zhao Shaoyong Jiang Ruoxi Zhang Jing Xie 《Journal of Earth Science》 SCIE CAS CSCD 2019年第4期834-842,共9页
The effect of operating conditions on the time-dependent X-ray intensity variation is of great importance for the optimal EPMA conditions for accurate determinations of various elements in carbonate minerals. Beam dia... The effect of operating conditions on the time-dependent X-ray intensity variation is of great importance for the optimal EPMA conditions for accurate determinations of various elements in carbonate minerals. Beam diameters of 0, 1, 2, 5, 10, 15, and 20 μm, and beam currents of 3, 5, 10, 20,and 50 nA were tested. Ca, Mg, Zn, and Sr were found to be more sensitive to electron beam irradiation as compared to other elements, and small currents and large beam diameters minimized the timedependent X-ray intensity variations. We determined the optimal EPMA operating conditions for elements in carbonate: 10 μm and 5 nA for calcite;10 μm and 10 nA for dolomite;5 μm and 10 nA or 10 μm and 20 nA for strontianite;and 20 nA and 5 μm for other carbonate. Elements sensitive to electron beam irradiation should be determined first. In addition, silicate minerals are preferred as standards rather than carbonate minerals. 展开更多
关键词 CARBONATE minerals:electron probe microanalysis characteristic X-ray TIME-DEPENDENT intensity BEAM current BEAM DIAMETER
原文传递
Electron probe microanalysis for revealing occurrence mode of scandium in Bayer red mud 被引量:7
4
作者 Na Zhang Hong-Xu Li +1 位作者 Hui-Jing Cheng Xiao-Ming Liu 《Rare Metals》 SCIE EI CAS CSCD 2017年第4期295-303,共9页
Red mud is a bauxite residue generated during the process of alumina production. In this research, the occur- rence mode of scandium in the Bayer red mud was investi- gated mainly by electron probe microanalysis (EPM... Red mud is a bauxite residue generated during the process of alumina production. In this research, the occur- rence mode of scandium in the Bayer red mud was investi- gated mainly by electron probe microanalysis (EPMA). The Bayer red mud used in this work is composed of 21.47 wt% hematite, 12.13 wt% goethite, 8.86 wt% gibbsite, 5.02 wt% perovskite, 9.70 wt% quartz, 3.23 wt% anhydrite, 29.92 wt% Na_2Al_2Si_5O_14 and 9.67 wt% Al_3Fe_5O_12. Besides, the scandium content in the Bayer red mud is 84.32 × 10-6, indicating that this Bayer red mud is an important scandium resource deserving exploitation. The EPMA results show that the scandium within the Bayer red mud is mainly occurring in the iron minerals of hematite and goethite with the isomorphism form, but its distribution is not homogeneous in these iron minerals with the Sc_2O_3 content between 330 × 10-6 and 2040 × 10-6. This study provides a theoretical base for the further experimental work on the scandium extraction from this Bayer red mud. 展开更多
关键词 SCANDIUM Occurrence mode Bayer red mud Electron probe microanalysis
原文传递
Microanalysis and preliminary pharmacokinetic studies of a sulfated polysaccharide from Laminariajaponica 被引量:4
5
作者 张文静 孙德林 +3 位作者 赵峡 金维华 王晶 张全斌 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2016年第1期177-185,共9页
A rapid, sensitive and reproducible high performance liquid chromatography (HPLC) method with post-column fluorescence derivatization has been developed to determine the amount of low-molecular- weight sulfated poly... A rapid, sensitive and reproducible high performance liquid chromatography (HPLC) method with post-column fluorescence derivatization has been developed to determine the amount of low-molecular- weight sulfated polysaccharide (GFS) in vivo. The metabolism of GFS has been shown to fit a two component model following its administration by intravenous injection, and its pharmacokinetic parameters were determined to be as follows: half-time of distribution phase (t1/2α)=11.2±2.93 min, half-time of elimination phase (tl/2α)=98.20±25.78 min, maximum concentration (Cmax)=110.53 gg/mL and peak time (Tmax)=5 min. The pharmacokinetic behavior of GFS was also investigated following intragastric administration. However, the concentration of GFS found in serum was too low for detection, and GFS could only be detected for up to 2 h after intragastric administration (200 mg/kg body weight). Thus, the bioavailability of GFS was low following intragastric administration because of the metabolism of GFS. In conclusion, HPLC with post-column derivatization could be used for quantitative microanalysis and pharmacokinetic studies to determine the presence of polysaccharides in the serum following intravenous injection. 展开更多
关键词 sulfated polysaccharide HPLC post-column derivatization microanalysis PHARMACOKINETICS
原文传递
Microanalysis of Multi-Element in Juncus effusus L. by LIBS Technique 被引量:3
6
作者 刘晓娜 黄建梅 +5 位作者 吴志生 张乔 史新元 赵娜 贾帅芸 乔延江 《Plasma Science and Technology》 SCIE EI CAS CSCD 2015年第11期904-908,共5页
Laser-induced breakdown spectroscopy (LIBS) was used to decipher the unique multi-elemental characteristics of Juncus effusus L. The spectral fingerprints of Juncus effusus L. were established based on elemental mic... Laser-induced breakdown spectroscopy (LIBS) was used to decipher the unique multi-elemental characteristics of Juncus effusus L. The spectral fingerprints of Juncus effusus L. were established based on elemental microanalysis via LIBS. Microanalysis and multimode sampling methodologies were designed in this study. The relative standard deviation (RSD) approach was performed to optimize the multi-shot measurements. Taking advantage of the capability with no or minimal sample pre-treatment of LIBS, a thermodynamic chart of four elements (Mg, Ca, Ba, and Na) was created from twelve collection regions. The diagram of elemental distribution on a micro-scale was generated to explore the nature of Juncus effusus L. by LIBS. The results demon- strated that LIBS is a promising technique for rapid elemental microanalysis of heterogeneous samples. 展开更多
关键词 LIBS Juncus effusus L. RSD approach thermodynamic chart elemental microanalysis MICRO-SCALE
在线阅读 下载PDF
Microanalysis on the Hydrogen Ion Irradiated 50 wt pct TiC-C Films 被引量:1
7
作者 Hui JIANG Yaoguang LIU Ningkang HUANG 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2007年第1期127-130,共4页
The 50 wt pct TiC-C films were prepared on stainless steel substrates by using a technique of ion beam mixing. These films were irradiated by hydrogen ion beam with a dose of 1×10^18 ions/cm^2 and an energy of 5 ... The 50 wt pct TiC-C films were prepared on stainless steel substrates by using a technique of ion beam mixing. These films were irradiated by hydrogen ion beam with a dose of 1×10^18 ions/cm^2 and an energy of 5 keV. Microanalysis of X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS) were used to analyze the films before and after hydrogen ion irradiation and to study the mechanism of hydrogen resistance. 展开更多
关键词 Titanium carbide Hydrogen ion irradiation microanalysis
在线阅读 下载PDF
Ore Microscopy and Microanalysis of the Nickeliferous Iron Ores from Komnina Vermion Area (N.W. Greece) 被引量:3
8
作者 Georgios Alevizos Eftychia Repouskou 《Geomaterials》 2011年第2期46-50,共5页
Nickel laterites are considerable sources of nickel. To be successfully exploited it is important to know the mineralogical and microstructural characteristics of the ore. Besides, the identification of the mineralogi... Nickel laterites are considerable sources of nickel. To be successfully exploited it is important to know the mineralogical and microstructural characteristics of the ore. Besides, the identification of the mineralogical components as well as the fabric description, can lead to the interpretation of the mechanism of deposit genesis. The aim of the present study is the microscopic and microanalytical investigation of the Fe-Ni ores from Komnina Vermion area (N.W. Greece). The mineralogical composition of the ore is mainly hematite, quartz, chromite and chlorite, while in minor quantities goethite, nickeliferous chlorite, serpentine, talc and calcite are also present. The ore structure is allotriomorphic inequigranular and the texture is oolitic-pisolitic. According to microscopic examination the deposit can be registered as a secondary pseudo-autochthonous. 展开更多
关键词 ORE MICROSCOPY microanalysis Fe-Ni-Ores Komnina-Vermion (Greece).
暂未订购
Detection of distribution of copper inside and outside of lysosomes in cultured hepatolenticular degeneration fibroblasts by electron probe X-ray microanalysis
9
作者 Wen Liu Jin-Yan Li +1 位作者 Ji Jin Ji Zuo the Department of Medical Genetics, Scholl of Medicine, Fudan University, Shanghai 200032, China Department of Biology, Zhenjiang Medical College, Zhenjiang 212000, China 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS 2003年第2期586-589,共4页
OBJECTIVE: To observe the distribution of copper in the subcellular structure for the understanding of primary pathogenesis of hepatolenticular degeneration (HLD). METHODS: Skin fibroblasts taken from HLD patients wer... OBJECTIVE: To observe the distribution of copper in the subcellular structure for the understanding of primary pathogenesis of hepatolenticular degeneration (HLD). METHODS: Skin fibroblasts taken from HLD patients were cultured as an in vitro model of HLD, and the control cells taken from healthy volunteers were clutured in the same way. The distribution of copper inside and outside of lysosomes in fibroblasts was detected by quantitative electron probe X-ray microanalysis. The relationship between the subcellular location of copper and the genotype of the patients, and relationship between the distribution of copper and the course of the disease were analyzed. RESULTS: The content of Cu^(2+) inside lysosomes of HLD cells (14.6±2.1 mmol/kg) and of heterozygote cells (11.6±0.6 mmol/kg) was higher than that of normal cells (4.5±1.2 mmol/kg) (P<0.01). The content of Cu^(2+) outside lysosomes of HLD cells (17.5±4.2 mmol/kg) and of heterozygote cells (12.0±0.9 mmol/kg) was higher than that of normal cells (4.7±1.2 mmol/kg) (P<0.01). The distribution of copper in the subcellular structure was correlated with disease courses of HLD patients. With the progression of the disease, more copper was deposited in lysosomes (r=0.85, P<0.01). The content of copper in the diffused cytoplasmic compartment in HLD cells was correlated with that of sulfur (r=0.86, P<0.05), but not in heterozygote and normal cells. CONCLUSIONS: In the early stage of HLD, copper is accumulated outside lysosome, which is paralleled with increase of metallothionein-like proteins (copper and sulfur-binding proteins). With the development of the disease, more copper is deposited inside lysosome than outside lysosome. We conclude that the up-regulation expression of copper and sulfur-binding proteins and copper accumulation in lysosomes may play an important role in lowering the ATP7B gene mutation-induced toxic effects of free copper on the cell. 展开更多
关键词 hepatolenticular degeneration FIBROBLAST LYSOSOME electron probe X-ray microanalysis copper-binding protein
暂未订购
Electron probe microanalysis оf experimentally stimulated osteoarthrosis in dogs
10
作者 Tatyana Stupina Michael Shchudlo Michael Stepanov 《World Journal of Orthopedics》 2017年第9期681-687,共7页
AIM To develop methods of articular cartilage preparation for X-ray-electron probe microanalysis and to study its elements content in experimental osteoarthrosis.METHODS Twenty dogs aged 2-8 years were divided in rese... AIM To develop methods of articular cartilage preparation for X-ray-electron probe microanalysis and to study its elements content in experimental osteoarthrosis.METHODS Twenty dogs aged 2-8 years were divided in research(aged 2 years, induction of osteoarthrosis-IOA) and intact group. Intact group included three subgroups(aged 2, 5 and 8 years). Samples of cartilage after araldite saturation and pouring were partially cut into semithin sections stained with methylene blue and with methylene blue-basic fuchsin. Their smooth surfaces were investigated by X-ray-electron probe microanalysis. Spatial distribution of sulfur, calcium and phosphorus and their concentrations(weight %) were investigated.RESULTS X-ray electron probe microanalysis revealed non-uniformsulfur distribution in cartilage of intact animals: Its content increases from superficial zone to deep one, this regularity was preserved in animals with IOA. Differences of IOA with spontaneous chondropathy were revealed. Spontaneous aging was characterized by calcium and phosphorus storage in deep and calcified zones and compensatory increase of sulfated glycosaminoglycans in intermediate and deep cartilage zones as evidenced by the metachromatic reaction and microanalysis data. Unlike spontaneous chondropathy connected with aging in experimentally stimulated osteoarthrosis more intensive storage of calcium but minor phosphorus in intermediate zone were marked. In IOA the calcified cartilage thinning and osteoclastic resorption are apparent with few changes of elements composition; the only difference from control is minority phosphorus content.CONCLUSION The obtained results demonstrate specific tricks of X-ray electron probe microanalysis and its possibility in the research of mechanisms of articular cartilage alterations in osteoarthrosis. 展开更多
关键词 OSTEOARTHROSIS ARTICULAR CARTILAGE DOG X-ray electron probe microanalysis
暂未订购
Multielemental Microanalysis in Root and Leaves, Growth and Biomass in Tomato Seedling in Response to Ca Levels and Induction of Stress: Non-Destructive Spectroscopy
11
作者 Omar A. Pérez-Dueñas Fanny Hernández-Mendoza +1 位作者 Víctor García-Gaytán Soledad García-Morales 《Open Journal of Applied Sciences》 2021年第6期672-683,共12页
Tomatoes are one of the main vegetables in the food industry that are consumed fresh and processed. A multi-element microanalysis was performed with the use of scanning electron microscopy (SEM) in conjunction with en... Tomatoes are one of the main vegetables in the food industry that are consumed fresh and processed. A multi-element microanalysis was performed with the use of scanning electron microscopy (SEM) in conjunction with energy dispersion spectroscopy (EDS), to see changes in nutrient concentration in roots and leaves, as well as fresh and dry biomass in tomato seedlings. Exposed in nutrient solution (NS) with different levels of Ca (control, 25, 50 and 100 mM). The root was put in also<span lang="EN-US" style="font-size:10pt;font-family:;" "=""> </span><span lang="EN-US" style="font-size:10pt;font-family:;" "="">to H<sub>2</sub>O<sub>2</sub> for 8 hours to observe the changes that occurred. It was observed that NS with 100 mM Ca in fresh stem biomass and fresh leaf biomass increased by 25% and 38% compared to the control. It was observed that the NS with 100 and 50 mM of Ca, the content of Ca and Cl in foliar tissue increased by 34.50% and 13.15% compared to the control. Treatment with H<sub>2</sub>O<sub>2</sub> and with 25 and 100 mM of Ca at NS increased the height of the seedling and fresh leaf bio-mass by 19.75% and 60.80% compared to the control. The treatment with H<sub>2</sub>O<sub>2</sub> and with the different levels of Ca in the NS increased the content of C, P, K, Ca and Cl in the leaf tissue. Only S was significant for the control. Treatment with H<sub>2</sub>O<sub>2</sub> and 100 mM Ca in the NS increased Ca and Mg by 83.48% and 40.47% for the root compared to the control. The K and Cl in the root was higher in the control treatment by 47.61% and 55% respect to the highest level of Ca.</span><span lang="EN-US" style="font-size:10pt;font-family:;" "=""> </span><span lang="EN-US" style="font-size:10pt;font-family:;" "="">It is concluded that multielemental microanalysis is a powerful, non-destructive, fast and accurate tool for the determination of plant nutrients. Also, it is applicable for the areas like horticulture, physiology and agronomy.</span> 展开更多
关键词 microanalysis Nutrient Solution CALCIUM ROOT LEAVES Stem
在线阅读 下载PDF
高掺量胶粉改性沥青老化作用机理 被引量:3
12
作者 杨三强 高毅松 +2 位作者 刘琦 李成旺 刘娜 《科学技术与工程》 北大核心 2025年第15期6486-6492,共7页
为了探究高掺量胶粉改性沥青的老化作用机理,借助20%、25%和30%三种不同掺量的橡胶沥青,采用四组分分析实验和红外光谱实验,评价老化橡胶沥青的四组分指标变化,并分析老化前后的化学组成和官能团变化,通过对比研究,揭示高掺量胶粉改性... 为了探究高掺量胶粉改性沥青的老化作用机理,借助20%、25%和30%三种不同掺量的橡胶沥青,采用四组分分析实验和红外光谱实验,评价老化橡胶沥青的四组分指标变化,并分析老化前后的化学组成和官能团变化,通过对比研究,揭示高掺量胶粉改性沥青在不同老化条件下的老化机理。结果表明:老化对高掺量胶粉改性沥青的组分影响更显著。20%掺量时,饱和分、芳香分和胶质分别降4.4%、3.4%、4.3%,沥青质增117.7%;25%掺量橡胶沥青饱和分下降5.0%、芳香分下降8.4%、胶质下降4.9%、沥青质增加119.3%,30%掺量时,降幅更大,分别为7.4%、9.5%、6.0%,沥青质增至128.9%;老化过程中,高掺量胶粉改性沥青的质量损失较小,沥青中轻质组分结合与裂解橡胶结合减少了轻质组分活性并增强了抗老化性;高掺量改性沥青在老化条件下羰基与亚砜基指数增长更显著,可能导致性能下降,其橡胶与沥青的相容性在老化中更易受影响,表现为更剧烈的硫化现象和分子链交联的变化。研究成果为橡胶沥青老化作用机理提供了理论支撑,并为高掺量胶粉沥青路面的实际应用与养护提供了借鉴,对提升橡胶沥青路面性能具有重要意义。 展开更多
关键词 改性沥青 高掺量胶粉 老化机理 四组分 微观分析
在线阅读 下载PDF
岩溶地质高背景区土壤镉(Cd)富集机理研究现状
13
作者 李博 刘旭 +5 位作者 余涛 林坤 刘卫 师华定 何泽新 杨忠芳 《岩矿测试》 北大核心 2025年第5期937-951,共15页
自然界中,碳酸盐岩为Cd等微量元素含量偏低的贫Cd成土母岩类型,但在岩溶出露区,土壤却普遍呈现Cd等微量元素富集的现象,具备典型的地质高背景特征,其中Cd来源不明,富集机理不清,引发了学术界的高度关注与系统研究。鉴于碳酸盐岩原位风... 自然界中,碳酸盐岩为Cd等微量元素含量偏低的贫Cd成土母岩类型,但在岩溶出露区,土壤却普遍呈现Cd等微量元素富集的现象,具备典型的地质高背景特征,其中Cd来源不明,富集机理不清,引发了学术界的高度关注与系统研究。鉴于碳酸盐岩原位风化成土的广谱性,多数研究以此为切入点,结合两阶段风化成土、交代溶蚀成土、等容置换成土等理论,运用成土剖面、淋滤溶解实验、天然母质研究等手段,揭示原生继承与次生吸附综合作用下岩溶区Cd的迁移转化规律。岩溶区土壤相对于原岩普遍富集Cd等元素,但是富集效应在整个风化过程中并非是持续性的:①成土母质的形成与演化阶段为Cd富集的主要阶段,这一阶段Cd的富集主要归因于成土母质为土壤形成初期提供的高Cd来源以及磷灰石、黏土矿物、Fe-Mn氧化物对Cd的吸附;②成土过程是Cd的淋失过程,载体矿物的淋失和水解是Cd淋失的主要驱动力,由此引发的Cd活化也给岩溶地质高背景区带来了潜在的环境风险。目前,岩溶区风化成土过程中Cd迁移宏观规律的研究相对较为完善,但在研究方法和分析测试的层面仍可以进一步优化。本文建议研究过程尽量确保风化过程的连续性和完整性,在把握宏观规律的基础上,进一步深入揭示微观机制,为构建岩溶区土壤Cd富集的理论框架提供科学依据,同时也为岩溶地质高背景区土地资源的分类管理及生态环境的科学管护提供新的思路与方法。 展开更多
关键词 岩溶区 地质高背景 土壤 CD 富集机制 微区原位分析
在线阅读 下载PDF
混掺再生粗骨料和再生微粉混凝土的早期力学性能 被引量:6
14
作者 毕钰 秦拥军 +3 位作者 罗玲 姚子祺 刘凤超 阳毅恒 《硅酸盐通报》 北大核心 2025年第2期623-633,共11页
针对建筑固废利用率较低的问题,本文对使用不同获取方式和取代方式的再生微粉与再生粗骨料制备的混凝土抗压强度进行了试验研究,并建立了同时掺入再生微粉和再生粗骨料混凝土的早期抗压强度时变规律预测模型,并分析了制备混凝土的碳足... 针对建筑固废利用率较低的问题,本文对使用不同获取方式和取代方式的再生微粉与再生粗骨料制备的混凝土抗压强度进行了试验研究,并建立了同时掺入再生微粉和再生粗骨料混凝土的早期抗压强度时变规律预测模型,并分析了制备混凝土的碳足迹。研究包括超量取代与常量取代的对比,以及研磨获取的再生微粉与筛分获取的再生微粉的对比。结合扫描电子显微镜和压汞法对混凝土试样进行了微观测试,分析了混凝土强度变化微观层面的原因。结果表明,再生微粉对混凝土力学性能的影响比再生粗骨料明显。随着再生微粉掺量从0%增加到30%(质量分数),试块早期抗压强度的发展逐渐减慢,孔隙率则迅速增加,且多害孔的占比也会增加。此外,以再生微粉和再生粗骨料取代率为参数建立的再生混凝土早期抗压强度时变规律预测模型拟合程度良好,可在工程实践中作为参考。 展开更多
关键词 再生微粉 再生粗骨料 抗压强度 碳足迹 预测模型 微观分析
在线阅读 下载PDF
基于机器学习的磷石膏轻骨料混凝土配合比设计与力学性能研究 被引量:2
15
作者 苏瑛 龚伟 +1 位作者 刘川北 张俊 《硅酸盐通报》 北大核心 2025年第5期1656-1665,共10页
采用磷石膏轻粗骨料替代天然碎石制备轻骨料混凝土,是实现磷石膏资源综合利用的有效技术。本文结合轻骨料混凝土的配合比设计原理与BP神经网络模型,提出了一种预测小粒径磷石膏轻骨料混凝土力学性能的方法。结果表明,混凝土的抗压强度... 采用磷石膏轻粗骨料替代天然碎石制备轻骨料混凝土,是实现磷石膏资源综合利用的有效技术。本文结合轻骨料混凝土的配合比设计原理与BP神经网络模型,提出了一种预测小粒径磷石膏轻骨料混凝土力学性能的方法。结果表明,混凝土的抗压强度和劈裂抗拉强度随着净水灰比升高而减小,随着砂率升高而增大,随着水泥用量升高略有降低,三种影响因素的显著程度次序为净水灰比、砂率、水泥用量。适当减小净水灰比,采用高砂率和低水泥用量可以减少界面过渡区孔隙和初始微裂纹的产生,并使整体力学强度提升。构建的BP神经网络模型对小粒径磷石膏轻骨料混凝土力学强度预测的准确度较高。本研究旨在为磷石膏轻骨料混凝土配合比设计优化和力学强度预测提供借鉴。 展开更多
关键词 磷石膏轻骨料 混凝土 抗压强度 劈裂抗拉强度 BP神经网络 微观分析
在线阅读 下载PDF
HNO_(3)和H_(2)SO_(4)侵蚀作用下地质聚合物固化软土的抗酸性能研究 被引量:1
16
作者 蒋新彧 征西遥 +2 位作者 吴俊 杨爱武 李博 《岩土力学》 北大核心 2025年第3期851-866,共16页
为解决水泥固化软土抗酸性能差及制备水泥时高污染、高能耗及高成本等问题,拟采用低成本的工业固体废弃物(不同矿渣(ground granulated blast furnace slag,简称GGBFS)与粉煤灰(fly ash,简称FA)比例)为前驱剂,固体氢氧化钠为激发剂,以... 为解决水泥固化软土抗酸性能差及制备水泥时高污染、高能耗及高成本等问题,拟采用低成本的工业固体废弃物(不同矿渣(ground granulated blast furnace slag,简称GGBFS)与粉煤灰(fly ash,简称FA)比例)为前驱剂,固体氢氧化钠为激发剂,以“一步法”制备地质聚合物浆料用以固化软土。继而将地质聚合物固化软土试样分别浸润在不同pH值(2、4、6)的HNO_(3)和H_(2)SO_(4)溶液中,以质量损失、无侧限抗压强度(unconfined compression strength,简称UCS)、中性化深度(neutralization depth,简称ND)和pH值等4个指标对固化软土在不同侵蚀龄期(30、60、120、240 d)下的抗酸性能进行评估。并通过扫描电子显微镜-能谱仪(scanning electron microscope-energy dispersive spectrometer,简称SEM-EDS)研究试样在不同酸性环境侵蚀下的微观结构和水化产物组成的变化,揭示其劣化机制。试验结果表明:相较于H^(2)SO_(4)溶液,HNO_(3)溶液对固化软土的酸侵蚀较为缓和,其主要是由于固化软土中Ca^(2+)、K^(+)和Na^(+)离子在水中形成硝酸盐,可中和NO_(3)^(-)离子的侵蚀,从而缓解固化软土性能的劣化;当GGBFS与FA质量比为80:20时,地质聚合物固化软土的抗酸侵蚀性能达到最优,表明适量掺入FA可使试样形成致密的微观结构,有效阻碍H^(+)、NO_(3)^(-)和SO_(4)^(2-)离子侵入。研究结果可拓展低成本工业固体废弃物的应用范围,为一步法地质聚合物固化软土的耐久性评估奠定理论基础。 展开更多
关键词 地质聚合物 抗酸性 固化软土 微观分析
原文传递
秸秆纤维增强镁渣固化锂渣力学性能与微观特征研究 被引量:1
17
作者 郭乔明 陈峰 +3 位作者 赵华 杨璐 陈慧 温久然 《混凝土》 北大核心 2025年第3期128-132,共5页
为有效解决海量锂渣、镁渣等大宗工业固废限制新能源及冶金行业发展的问题,实现锂渣、镁渣等固废在道路工程中的资源化.以镁渣作为主固化剂,采用秸秆纤维加筋的方法对锂渣进行固化处理并制备了适用于路面基层的秸秆纤维增强镁渣-锂渣复... 为有效解决海量锂渣、镁渣等大宗工业固废限制新能源及冶金行业发展的问题,实现锂渣、镁渣等固废在道路工程中的资源化.以镁渣作为主固化剂,采用秸秆纤维加筋的方法对锂渣进行固化处理并制备了适用于路面基层的秸秆纤维增强镁渣-锂渣复合固化材料(MS-LS).通过无侧限抗压强度测试研究了MS-LS的力学性能,结合XRD与SEM试验探究了MS-LS的微观结构特征以及固化机理.结果表明:MS-LS的抗压强度随着纤维掺量的增加呈现先增后减的趋势.当秸秆纤维掺量为0.2%、纤维长度为250μm的抗压强度峰值达到了4.25 MPa,相较于830μm-0.1%组(1.436 MPa)提高了1.96倍;强度的显著增大主要归因于水化硅酸钙(C-S-H)凝胶对LS颗粒的胶结固化作用以及秸秆纤维加筋增强作用.颗粒嵌挤填充作用及石膏相水化硬化作用也促进了结构强度的形成与发展;在镁渣掺量为6%的条件下,秸秆纤维对于MS-LS的增强作用存在的最佳掺量为0.2%,最佳纤维长度为250μm。 展开更多
关键词 固废处置 秸秆纤维 抗压强度 微观分析
在线阅读 下载PDF
锆石激光原位微区U-Th-Pb-He双定年分析方法进展 被引量:1
18
作者 刘文博 陶霓 +1 位作者 孙敬博 温汉捷 《矿物岩石地球化学通报》 北大核心 2025年第1期162-177,共16页
锆石激光原位微区U-Th-Pb-He双定年方法是一项结合锆石激光原位微区(U-Th)/He和U-Pb定年技术的前沿方法,该方法能够实现同时在锆石矿物微区上获得(U-Th)/He和U-Pb两种同位素体系年龄数据。U-Th-Pb-He双定年技术不仅显著提高了(U-Th)/He... 锆石激光原位微区U-Th-Pb-He双定年方法是一项结合锆石激光原位微区(U-Th)/He和U-Pb定年技术的前沿方法,该方法能够实现同时在锆石矿物微区上获得(U-Th)/He和U-Pb两种同位素体系年龄数据。U-Th-Pb-He双定年技术不仅显著提高了(U-Th)/He定年的分析效率,而且使得(U-Th)/He和U-Pb两种年龄数据更为紧密地耦合起来,从而揭示矿物及其赋存岩石地层丰富的热演化历史,增强了这两种同位素年代学体系年龄数据解释的有效性与可靠性。本文系统梳理了锆石激光原位微区U-Th-Pb-He双定年方法的发展历程与现状,收集了已发表的相关标准样品与自然样品数据,并尝试分析已有测试数据中可能存在的技术难点与挑战。目前,U-Th-Pb-He双定年方法及其技术流程已能提供一定精准度与空间分辨率的同位素和年龄数据,尽管仍然存在着一些技术困难,包括^(4)He含量的精准测量、U-Th微区不均一和含U-Th显微包裹体对U-Th同位素含量定量分析的影响等,已有相应的解决方法。国内外相关实验室针对U-Th-Pb-He双定年方法的上述技术问题正在持续开展深入的理论与实验研究,相关进展有望促进锆石U-Th-Pb-He双定年分析数据精准度、可靠性与可解释性,为地球科学相关领域的研究提供更为准确可靠的技术支撑。 展开更多
关键词 (U-Th)/He U-PB 双定年 锆石 激光原位微区
原文传递
辉钼矿激光微区Re-Os同位素定年进展
19
作者 王邑嘉 杨岳衡 +5 位作者 储著银 吴石头 王浩 谢烈文 杨进辉 许继峰 《岩石学报》 北大核心 2025年第12期4288-4304,共17页
辉钼矿作为一种重要的金属硫化物广泛存在于热液矿床中,它是稀有金属钼和铼的主要赋存矿物,其Re-Os同位素定年是金属矿床经典的定年方法。辉钼矿Re-Os法可以直接测定金属矿床的成矿年代,是直接获取金属硫化物矿床形成时代最有效的手段... 辉钼矿作为一种重要的金属硫化物广泛存在于热液矿床中,它是稀有金属钼和铼的主要赋存矿物,其Re-Os同位素定年是金属矿床经典的定年方法。辉钼矿Re-Os法可以直接测定金属矿床的成矿年代,是直接获取金属硫化物矿床形成时代最有效的手段。同位素稀释法辉钼矿Re-Os同位素定年(ID-NTIMS或ID-ICP-MS)经历了三十余年发展,已经非常成熟。但是整体分析需要较大的样品量,涉及冗长的化学分离纯化过程,也掩盖了精细的空间变化信息。近年来,辉钼矿激光微区Re-Os定年发展迅速,它不仅能够避免整体分析的不足,而且可以实现薄片中辉钼矿原位测年,具有广泛的应用前景。本文综述了辉钼矿激光微区Re-Os定年方法最新进展,总结了其发展的两个主要阶段,指出了当前的难点问题与应对策略,展望了辉钼矿和黄铁矿等矿物激光微区Re-Os定年的广阔前景,获得如下认识:(1)等离子串联质谱,大大降低了^(187)Re对^(187)Os的干扰,对高Re含量(>10×10^(-6)Re)辉钼矿、黄铁矿等硫化物可以进行激光微区187 Re-187 Os定年。元素成像技术不但能揭示辉钼矿微量元素之间关系,而且快速锁定矿物高Re/Os区域,提高硫化物^(187)Re-^(187)Os定年成功率。(2)选择性活性气体,笑气与Re反应效率低于甲烷,其干扰消除能力优于甲烷。甲烷能够提高Os产物反应效率,但是其与Re反应效率也高于笑气,因此,笑气更加适合年轻辉钼矿激光微区^(187)Re-^(187)Os定年,结合高灵敏多接收磁式串联质谱(MC-ICP-MS/MS)有望实现硫化物激光微区高精度^(187)Re-^(187)Os定年。(3)^(187)Re与^(187)Os干扰并未彻底消除,仍然需要进行干扰校正,探寻合适的活性气体,尽量降低甚至消除Re反应产物,同时提高Os灵敏度与反应效率,是当前辉钼矿激光微区Re-Os定年难点,也是未来硫化物激光微区Re-Os定年的前沿领域与发展方向。(4)实验方法与标准物质研发相辅相成、相互促进,硫化物激光微区Re-Os定年标准物质的严重缺乏仍是当前迫切需要解决的关键难题。可以相信,随着技术不断进步,硫化物激光微区Re-Os定年有可能像锆石等副矿物激光微区U-Pb定年一样,变得简便、快捷和高效,为金属矿床成矿年代学的研究打开一扇新窗口,提供一种新手段。 展开更多
关键词 辉钼矿 激光微区分析 同位素定年 Re-Os年代学
在线阅读 下载PDF
椰壳纤维加筋石灰改良土力学性能试验研究
20
作者 李丽华 刘文 +2 位作者 李玉涛 王翠英 叶治 《工程科学与技术》 北大核心 2025年第6期131-141,共11页
为进一步提高石灰土在工程中的适用性,解决植物椰壳纤维合理利用的问题,对椰壳纤维改性石灰土进行试验研究。通过开展无侧限抗压强度试验、干湿循环试验,核磁共振(NMR)试验和扫描电镜(SEM)试验,分析不同养护龄期、椰壳纤维掺量及干湿循... 为进一步提高石灰土在工程中的适用性,解决植物椰壳纤维合理利用的问题,对椰壳纤维改性石灰土进行试验研究。通过开展无侧限抗压强度试验、干湿循环试验,核磁共振(NMR)试验和扫描电镜(SEM)试验,分析不同养护龄期、椰壳纤维掺量及干湿循环次数对改性石灰土力学性能的影响规律,揭示纤维加筋石灰土力学性能改善的内在机理。结果表明:纤维的掺入改善了石灰土性质,随着椰壳纤维的增加,抗压强度呈现先增大后减小的趋势,但掺入纤维的石灰土强度比石灰土高;加入纤维后试样破坏形式由脆性变为塑性,纤维最优掺量为0.75%。养护龄期越长,椰壳纤维石灰土抗压强度越大,在破坏应变时抵抗变形需要吸收的能量越多。随着干湿循环次数增加,土体质量损失率逐渐增加;压实度相同时,纤维石灰土抗压强度随干湿循环次数的增加先上升后下降,在第1次循环时抗压强度最大;循环次数与纤维掺量一定时,压实度越大试样抗压强度越大。微观试验显示:随着干湿循环次数增加,土体孔隙呈现先减小后增大的趋势;椰壳纤维的加入虽然使石灰土中孔隙显著增多,但椰壳纤维可以引导水化物分布,产生黏结力,且受力时与土体产生较大摩擦力,限制土体变形,从而有效抑制破坏面的扩展。研究结果可为椰壳纤维石灰土在实际工程中的应用提供参考。 展开更多
关键词 椰壳纤维 石灰 无侧限抗压强度 干湿循环 微观分析
在线阅读 下载PDF
上一页 1 2 35 下一页 到第
使用帮助 返回顶部