期刊文献+
共找到36,848篇文章
< 1 2 250 >
每页显示 20 50 100
Genesis of the Jiuqu gold deposit, Jiaodong gold province, China: Constraints on the texture, mineral geochemistry, and sulfur isotope of pyrite
1
作者 Senmiao Xue Yayun Liang +6 位作者 Lei Shu Wenhao Xue Chenxi Zhang Chonghui Shen Bi He Haiyi Wang Yayi Fang 《Acta Geochimica》 2025年第3期631-647,共17页
The Linglong gold ore field is situated in the northwestern region of the Jiaodong gold province,China,with over 1000 tons of gold resources.Although the metallogenic mechanism and fluid sources of the Linglong gold d... The Linglong gold ore field is situated in the northwestern region of the Jiaodong gold province,China,with over 1000 tons of gold resources.Although the metallogenic mechanism and fluid sources of the Linglong gold deposit have been the subject of extensive discussion and analyzed by numerous scholars,a definitive conclusion remains elusive.The Jiuqu Au deposit is a significant metallogenic area in the eastern part of the Linglong gold ore field,characterized as a quartz vein-type gold deposit.Gold mineralization in the Jiuqu gold deposit is classified into four stages,primarily occurring within the Late Jurassic Linglong granite and Early Cretaceous Guojialing granodiorite.Pyrite,the primary gold-bearing mineral at the Jiuqu Gold Mine,has been present throughout the metallogenic period,is rich in a variety of trace elements and is closely related to the formation of gold ore.This study focused on evaluating pyrite from the essential metallogenic stages(Stages Ⅰ-Ⅲ)of the Jiuqu gold deposit using scanning electron microscopy(SEM),electron microprobe analysis(EMPA),laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS) and laser ablation multi-collector inductively coupled plasma mass spectrometry(LA-MC-ICP-MS) sulfur isotope analysis and detection.The work aimed to reconstruct the origin of metallogenic materials and the evolution of ore-forming fluids and to restrict the genesis of the deposit.Pyrite exhibits discernible alterations in both shape and crystal structure as it progresses through its ore-forming stages.The aforementioned stages can be delineated as follows:type 1 pyrite(PyⅠ),developed in the initial ore stage,is characterized by coarse-to-medium-grained euhedral pyrite in Stage Ⅰ;type 2 pyrite(PyⅡ),developed in the second ore stage,appears during the middle stage of mineralization and is characterized by subhedral or anhedral pyrite;type 3 pyrite(PyⅢ),developed in the third ore stage,primarily occurred in the late-middle stages of mineralization.It is fragmented and coexists with various metal sulfides,including chalcopyrite,sphalerite and galena.The in situ major and elemental compositions of pyrites at Jiuqu indicate that Au,in the form of visible gold,exists in pyrites with low Au and Ag contents throughout all stages.PyⅠ had lower Pb,Bi,Co and Ni contents than those of PyⅡ.PyⅢ displayed decreased Pb,Bi,Co and Ni levels compared with PyⅡ.The δ34S values of the PyⅠ,PyⅡ and PyⅢ pyrite stages ranged from 7.19% to 8.71%,6.24% to 7.68% and 7.66% to 8.07%,respectively.According to the structural and geochemical analysis of pyrite,the ore-forming fluid of the Jiuqu gold deposit was derived from a magmatic-hydrothermal formation created by enriched lithospheric mantle-derived magma,mixing S from Precambrian metamorphic rocks.Previous studies on the H-O isotopes of quartz in the region's ores have indicated the presence of primary magma water.Additionally,studies concerning the C-O isotopes of carbonate minerals in ores have suggested that C may have originated from the mantle.Fluid migration and water-rock interaction resulted in sulfide and gold precipitation.In the Late Meosozoic,lithospheric thinning of eastern North China Craton led to up welling of astheno spheric mantle and partial melting of lithospheric mantle in the Jiaodong area.Under tectonic changes,magmatic-hydro thermal fluid migrated upward along fault structures to form a gold province. 展开更多
关键词 Jiaodong gold province Linglong gold ore fi eld PYRITE Source of ore-forming fl uids gold precipitation
在线阅读 下载PDF
2025版GOLD解读 被引量:2
2
作者 何权瀛 《中国医药导刊》 2025年第1期58-63,共6页
2025版慢性阻塞性肺疾病全球创议(GOLD)已发布,包括五章,第一章定义和概述,第二章诊断和评估,第三章慢阻肺的预防和管理,第四章慢阻肺急性加重的管理,第五章慢阻肺合并症。较以往版本,2025版GOLD在许多方面做出重大更新,删除了2024版GOL... 2025版慢性阻塞性肺疾病全球创议(GOLD)已发布,包括五章,第一章定义和概述,第二章诊断和评估,第三章慢阻肺的预防和管理,第四章慢阻肺急性加重的管理,第五章慢阻肺合并症。较以往版本,2025版GOLD在许多方面做出重大更新,删除了2024版GOLD中“第六章COVID-19与慢阻肺”,新增并扩充修订了人体肺功能变化轨迹、微生态失衡、肺功能检查、慢阻肺CT影像学检查、慢阻肺患者心血管病风险、气候变化对慢阻肺患者的相应影响、对慢阻肺患者的推荐疫苗、肺康复治疗的线上、线下及远程随访、随访期治疗药物、LABA+ICS患者停用ICS、肺动脉高压等有关内容。基于此,本研究针对2025版GOLD主要更新内容进行分析解读,并基于慢阻肺发病率问题、肺气肿问题、慢阻肺和肺结核关系问题、慢阻肺患者多种共存疾病的综合评估问题、稳定期慢阻肺的病情评估问题、不应推荐肺去神经靶向治疗问题、慢阻肺患者共存病问题、慢阻肺合并贫血问题、慢阻肺患者合并红细胞增多症问题、慢阻肺合并心力衰竭问题、PRISm的临床意义阐释问题、肺的过度充气问题、慢阻肺患者吸入ICS后是否会发生肺癌问题等进行讨论,以期为临床实践提供理论参考。 展开更多
关键词 慢性阻塞性肺疾病全球创议(gold) 慢性阻塞性肺疾病(慢阻肺) 肺功能 解读
暂未订购
一种面向卫星物联网的ZC‑Gold组合前导序列
3
作者 王文鼐 刘雨露 +1 位作者 陈睿 吴炜 《南京邮电大学学报(自然科学版)》 北大核心 2025年第3期1-7,共7页
低轨(Low Earth Orbit,LEO)卫星物联网的覆盖范围广,并发终端数众多,如果沿用非地面网络(Non‑terrestrial Network,NTN)现有规范下的Zadoff‑Chu(ZC)前导序列,共享信道高移动性产生的争用与接入时延问题较为突出。文中给出ZC和Gold两种... 低轨(Low Earth Orbit,LEO)卫星物联网的覆盖范围广,并发终端数众多,如果沿用非地面网络(Non‑terrestrial Network,NTN)现有规范下的Zadoff‑Chu(ZC)前导序列,共享信道高移动性产生的争用与接入时延问题较为突出。文中给出ZC和Gold两种序列逐元相乘的序列组合方案,得到一种新型前导码,称作ZGC。分析发现ZGC的扩容比达到ZC序列长度的平方,对周期139的前导码,扩容比的理论值超过一万倍。进一步就周期相关性、峰均比、立方度量和载波频偏(Carrier Fre‑quency Offset,CFO)相关性等前导序列的检验参数,对比计算了ZGC相较于ZC、Gold和部分改进方案的性能。使用多信道时隙Aloha模型分析了多并发争用的接入时延。结果表明,ZGC在实现更高前导容量的同时,可显著降低接入时延,并具更强的CFO免疫能力。 展开更多
关键词 卫星物联网 非地面网络 前导容量 ZC组合gold
在线阅读 下载PDF
Remote Sensing-based Machine Learning Techniques for Mapping Gold-Mineralized Alteration Zones in the Fatira Mine Area,Egypt
4
作者 Refaey EL-WARDANY JIAO Jiangang +7 位作者 Basem ZOHEIR Lobna KHEDR Mustafa KUMRAL LIU Lei Ibrahem ABU EL-LEIL Ahmed ORABI Lotfy ABD EL-SALAM Amr ABDELNASSER 《Acta Geologica Sinica(English Edition)》 2025年第4期1196-1223,共28页
In the Fatira(Abu Zawal)mine area,located in the northern Eastern Desert of Egypt,fieldwork and mineralogical analysis,integrated with machine learning techniques applied to Landsat-8 OLI,ASTER,and Sentinel-2 multi-sp... In the Fatira(Abu Zawal)mine area,located in the northern Eastern Desert of Egypt,fieldwork and mineralogical analysis,integrated with machine learning techniques applied to Landsat-8 OLI,ASTER,and Sentinel-2 multi-spectral imagery(MSI)data delineate gold-sulfide mineralization in altered rocks.Gold(Au)anomalies in hydrothermal breccias and quartz veins are associated with NE-oriented felsite dykes and silicified granitic rocks.Two main alteration types are identified:a pyrite-sericite-quartz and a sulfide-chlorite-carbonate assemblage,locally with dispersed free-milling Au specks.Dimensionality reduction techniques,including principal component analysis(PCA)and independent component analysis(ICA),enabled mapping of alteration types.Sentinel-2 PC125 composite images offered efficient lithological differentiation,while supervised classifications,i.e.,the support vector machine(SVM)of Landsat-8 yielded an accuracy of 88.55%and a Kappa value of 0.86.ASTER mineral indices contributed to map hydrothermal alteration mineral phases,including sericite,muscovite,kaolinite,and iron oxides.Results indicate that post-magmatic epigenetic hydrothermal activity significantly contributed to the Au-sulfide mineralization in the Fatira area,distinguishing it from the more prevalent orogenic gold deposits in the region. 展开更多
关键词 MINERALOGY gold exploration hydrothermal alteration Au-sulfide mineralization remote sensing machine learning Fatira gold mine EGYPT
在线阅读 下载PDF
Effect of antimony and arsenic on gold enhancement capture during iron matte smelting of refractory gold concentrate by exclusion method
5
作者 Bai-qi SUN Wei-feng LIU +3 位作者 Du-chao ZHANG Lin CHEN Xu-heng LIU Tian-zu YANG 《Transactions of Nonferrous Metals Society of China》 2025年第9期3134-3146,共13页
Based on the properties of antimony(Sb)and arsenic(As),a method was proposed to enhance gold recovery during iron matte smelting.The impact of Sb and As on gold enhancement capture was investigated using an exclusion ... Based on the properties of antimony(Sb)and arsenic(As),a method was proposed to enhance gold recovery during iron matte smelting.The impact of Sb and As on gold enhancement capture was investigated using an exclusion method.The results demonstrated that both Sb and As significantly improved the gold recovery rate.As the Sb or As content increased,the gold recovery rate increased.The enhancement effect of Sb was better than that of As,and the optimal results were achieved through the synergistic effects of Sb and As.Under optimized conditions,the gold recovery rate reached 97.12%,whereas the gold content in the slag decreased to 1.70 g/t.Sb captured and aggregated free gold as an Au-Sb alloy,whereas As-Fe alloy also captured free gold.The growth of the gold-captured phase size enhanced the settling velocity,thereby promoting gold recovery. 展开更多
关键词 refractory gold concentrate Au-Sb alloy As-Fe alloy enhancement effect iron matte capture gold
在线阅读 下载PDF
Development of a gold leaching reagent as an alternative to cyanide: Synthesis and performance evaluation
6
作者 Jinlin Li Chunbao Sun +2 位作者 Jue Kou Peilong Wang Xinyu Liu 《International Journal of Minerals,Metallurgy and Materials》 2025年第4期835-850,共16页
Cyanide is the most widely used reagent in gold production processes. However, cyanide is highly toxic and poses safety haz-ards during transportation and use. Therefore, it is necessary to develop gold leaching reage... Cyanide is the most widely used reagent in gold production processes. However, cyanide is highly toxic and poses safety haz-ards during transportation and use. Therefore, it is necessary to develop gold leaching reagents that can replace cyanide. This paper intro-duces a method for synthesizing a gold leaching reagent. Sodium cyanate is used as the main raw material, with sodium hydroxide and so-dium ferrocyanide used as additives. The gold leaching reagent can be obtained under the conditions of a mass ratio of sodium cyanate,sodium hydroxide, and sodium ferrocyanide of 15:3:1, synthesis temperature of 600℃, and synthesis time of 1 h. This reagent has a goodrecovery effect on gold concentrate and gold-containing electronic waste. The gold leaching rate of roasted desulfurized gold concentratecan reach 87.56%. For the extraction experiments of three types of gold-containing electronic waste, the gold leaching rate can reach over90% after 2 h. Furthermore, the reagent exhibits good selectivity towards gold. Component analysis indicates that the effective compon-ent in the reagent could be sodium isocyanate. 展开更多
关键词 gold leaching reagent sodium isocyanate electronic waste gold leaching rate SELECTIVITY
在线阅读 下载PDF
Gold Cross Oil Sells Out at CAEXPO
7
《China Report ASEAN》 2025年第9期59-59,共1页
Gold Cross,a Thai company specializing in herbal oils,has long combined Thailand’s traditional medicine with modern technology to deliver highquality health products.Invited by the China-ASEAN Expo(CAEXPO),the head o... Gold Cross,a Thai company specializing in herbal oils,has long combined Thailand’s traditional medicine with modern technology to deliver highquality health products.Invited by the China-ASEAN Expo(CAEXPO),the head of Gold Cross arrived at the exhibition hall with a mix of anticipation and slight anxiety and the company’s signature product in tow—Gold Cross yellow oil.Made with a unique Golden Cross traditional formula and infused with natural herbal extracts,the oil relieves muscle aches,insect bites,and dizziness.In Thailand,it is a household name and widely regarded as an all-purpose herbal remedy.At the expo booth,a Chinese buyer was pleasantly surprised after trying it. 展开更多
关键词 Herbal Oils golden cross traditional formula herbal oilshas natural herbal extractsthe traditional medicine Thai Company modern technology gold cross
在线阅读 下载PDF
基于Mi-Gold算法的γ能谱重构分析
8
作者 梁文超 张江梅 王嘉麒 《原子能科学技术》 北大核心 2025年第5期1126-1134,共9页
针对Gold算法在重构低能量分辨率γ能谱时面临的迭代次数多、弱峰计数率低等挑战,本文提出了一种基于Gold重构算法的迭代算法框架,并扩展出3种新型迭代算法。通过实验对新型迭代算法在γ能谱上的重构能力进行了分析研究。本文基于自研Na... 针对Gold算法在重构低能量分辨率γ能谱时面临的迭代次数多、弱峰计数率低等挑战,本文提出了一种基于Gold重构算法的迭代算法框架,并扩展出3种新型迭代算法。通过实验对新型迭代算法在γ能谱上的重构能力进行了分析研究。本文基于自研NaI(Tl)探测器通过蒙特卡罗仿真和实际测量,获得了低能量分辨率γ能谱。采用提出的3种新型算法,结合非负响应矩阵对γ能谱进行重构分析,并将结果与传统Gold算法进行对比。实验结果表明,Mi-Gold(比例因子m=1.9)算法在收敛速率和重构精度上均显著优于Gold算法,重构后的能谱特征峰更尖锐明确,峰位相对误差小于1%,有效提升了低能量段特征峰的重构效果。 展开更多
关键词 NAI(TL)探测器 gold算法 Γ能谱 能谱重构
在线阅读 下载PDF
Nanobubble-enhanced flotation of auriferous pyrite in gold ore: Behavior and mechanisms 被引量:1
9
作者 Zhongxian Wu Youjun Tao +2 位作者 Jincheng Ran Hongliang Dong Dongping Tao 《International Journal of Minerals,Metallurgy and Materials》 2025年第8期1826-1837,共12页
Gold ores in the Jiaozhou region of China are characterized by their abundant reserves,low grade,fine dissemination,and chal-lenges in upgrading.Froth flotation,with xanthate as the collector,is a commonly employed me... Gold ores in the Jiaozhou region of China are characterized by their abundant reserves,low grade,fine dissemination,and chal-lenges in upgrading.Froth flotation,with xanthate as the collector,is a commonly employed method for enriching auriferous pyrite from these ores.This study aimed to develop a more efficient flotation process by utilizing cavitation nanobubbles for a low-grade gold ore.Batch flotation tests demonstrated that nanobubbles significantly enhanced the flotation performance of auriferous pyrite,as evidenced by improved concentrate S and Au grades and their recoveries.The mechanisms underlying this enhancement were explored by investigat-ing surface nanobubble(SNB)formation,bulk nanobubble(BNB)attachment to hydrophobic pyrite surfaces,and nanobubble-induced agglomeration using atomic force microscopy(AFM)and focused beam reflectance measurement(FBRM).The results revealed that nan-obubble coverage on the pyrite surface is a critical factor influencing surface hydrophobicity and agglomeration.SNBs exhibited higher coverage on pyrite surfaces with increased surface hydrophobicity,flow rate,and cavitation time.Similarly,BNB attachment on pyrite surfaces was significantly increased with surface hydrophobicity and cavitation time.Enhanced surface hydrophobicity,along with higher flow rates and cavitation times,promoted pyrite particle agglomeration owing to the increased nanobubble coverage,ultimately leading to improved flotation performance. 展开更多
关键词 gold PYRITE FLOTATION cavitation nanobubble AGGLOMERATION mechanism
在线阅读 下载PDF
Study on Gold Self-Relay Catalytic Annulation/Nucleophilic Substitu-tion of 1,3-Enyne Acetates with Cyclic Ether Acetals
10
作者 Zhang Congyu Chen Xiaoqi +3 位作者 Meng Fantao Wang Haiying Hao Wen-Juan Jiang Bo 《有机化学》 北大核心 2025年第6期2199-2207,共9页
A new gold self-relay catalytic annulation/nucleophilic substitution cascade of 1,3-enyne acetates with cyclic ether acetals is reported,enabling highly diastereoselective access to cyclic etherified cyclopentenones w... A new gold self-relay catalytic annulation/nucleophilic substitution cascade of 1,3-enyne acetates with cyclic ether acetals is reported,enabling highly diastereoselective access to cyclic etherified cyclopentenones with cyclic quaternary centers in moderate to good yields and>19∶1 dr.This catalysis enables the direct construction of two types of carboncyclic skeletons by adjusting the olefin types of 1,3-enyne acetates.When 1,3-enyne acetates bearing a cyclic alkene unit were used,5~6 fused bicarbocyclic products were diastereoselectively synthesized,whereas the reaction of acyclic 1,3-enyne acetates resulted in five-memebered carbocyclic framework.Notably,cyclic ether acetals are commonly used as protecting groups in traditional multistep organic syntheses,and in this reaction,such reagents serve as electrophilic cyclic ether precursors,achieving new uses for old reagents.The current method demonstrates good functional group compatibility,a broad substrate scope and high diastereoselectivity,providing a new synthetic strategy toward functionalized cyclopentenones. 展开更多
关键词 gold self-relay catalysis Nazarov cyclization nucleophilic substitution 1 3-enyne acetates cyclic ether acetals
原文传递
Gold-catalyzed intermolecular amination of allyl azides with ynamides:Efficient construction of 3-azabicyclo[3.1.0]scaffold
11
作者 Chong-Yang Shi Jian-Xing Gong +5 位作者 Zhen Li Chao Shu Long-Wu Ye Qing Sun Bo Zhou Xin-Qi Zhu 《Chinese Chemical Letters》 2025年第2期356-360,共5页
Gold-catalyzed amination reactions based on azides viaα-imino gold carbene intermediates have attracted extensive attention in the past decades because this methodology leads to the facile and efficient construction ... Gold-catalyzed amination reactions based on azides viaα-imino gold carbene intermediates have attracted extensive attention in the past decades because this methodology leads to the facile and efficient construction of synthetically useful N-containing molecules,especially valuable N-heterocycles.However,successful examples of intermolecular generation ofα-imino gold carbenes by using azides as amination reagents are rarely explored probably due to the weak nucleophilicity of azides.Herein,we disclose an efficient gold-catalyzed intermolecular aminative cyclopropanation of ynamides with the allyl azides,enabling flexible synthesis of a wide range of valuable 3-azabicyclo[3.1.0]hex-2-ene derivatives in good to excellent yields with excellent diastereoselectivities.Importantly,this protocol represents the first use of allyl azide as an efficient amination reagent in gold-catalyzed alkyne amination reactions. 展开更多
关键词 gold AZIDES Alkynes AMINATION HETEROCYCLES
原文传递
Geological Characteristics and Preliminary Genesis Exploration of the Sakay Gold Deposit in Vientiane,Laos
12
作者 Demin Yang Chenming Liu +4 位作者 Yuan Qin Wei Huang Nan Yang Zheng Wang Yungang Xiang 《Journal of Environmental & Earth Sciences》 2025年第5期233-243,共11页
The Sakay gold deposit in Vientiane,Laos,is located in the Indochina landmass of the southeastern segment of the Tethys orogenic belt,specifically within the Vientiane-Pakse micro-landmass and the Vientiane-Pakse meta... The Sakay gold deposit in Vientiane,Laos,is located in the Indochina landmass of the southeastern segment of the Tethys orogenic belt,specifically within the Vientiane-Pakse micro-landmass and the Vientiane-Pakse metallogenic belt.This area is regionally significant for the concentration of minerals such as gold,copper,and tin.The host rocks of the deposit are intermediate volcanic lavas and volcanic tuffs,occurring in near-east-west brittle shear structural fractures through hydrothermal filling and metasomatism.The ore exhibits granular texture,subhedral texture,porphyritic texture,and oriented polycrystalline texture,with structural features such as disseminated,vein-like,and cataclastic breccia.The main ore minerals are pyrite,sphalerite,galena,and chalcopyrite,while the gangue minerals are primarily quartz,calcite,and dolomite.Gold is mainly present as included gold or fissure gold within the crystal lattices and microfractures of minerals such as pyrite and sphalerite.Based on mineral assemblages and generation timing,the mineralization can be divided into three stages:arsenopyrite-pyrite-dolomite-quartz(Ⅰ),sphalerite-galena-chalcopyrite-calcite(Ⅱ),and siderite(Ⅲ),with the latter stages often overlaying the former,showing evident cross-cutting and metasomatic phenomena.The surrounding rocks in the mining area are altered,mainly showing silicification,carbonatization,limonitization,sericitization,and chloritization.Preliminary studies suggest that this deposit is a low-temperature hydrothermal gold deposit within a brittle shear zone. 展开更多
关键词 Laos gold Deposit HYDROTHERMAL PORPHYRY Brittle Shear
在线阅读 下载PDF
Gold Nanoparticle-Incorporated Polyurethane/Collagen Nanofibrous Scaffold as a Potential Cardiac Patch
13
作者 Hadiyeh Mozaffari Parisa Javadi +1 位作者 Reza Faridi-Majidi Mohammad Ali Derakhshan 《Journal of Bionic Engineering》 2025年第4期1910-1925,共16页
Due to the limited regeneration capacity of myocardial tissue after infarction,designing tissue engineering scaffolds are in demand.In the present study,electrospun nanofibrous scaffolds were made out of polyurethane,... Due to the limited regeneration capacity of myocardial tissue after infarction,designing tissue engineering scaffolds are in demand.In the present study,electrospun nanofibrous scaffolds were made out of polyurethane,collagen and gold nanoparticles with random and aligned nanofiber morphologies.The nanoparticles were green-synthesized using saffron extract.Nanoparticle characterizations with UV-Vis.spectroscopy and DLS illustrated theoretical and hydrodynamic diameters of around 7 and 13 nm,respectively,having zeta potential of−37 mV.SEM and TEM micrographs showed the morphology and diameters of obtained nanofibers.Also,further characterization were done by ATR-FTIR,XRD and TGA investigations and degradation studies.Contact angle measurements showed hydrophilic nature of the scaffolds(59±0.6°for aligned PU/Col/Au50 nanofibers compared to 120±2.6°for random PU nanofibers).Mechanical testing demonstrated appropriate tensile properties of the scaffolds for cardiac tissue engineering(Young’s modulus:1.53±0.07 MPa for aligned PU/Col/Au50 nanofibers compared to 0.4±0.05 MPa for random PU nanofibers).Finally,alamar blue assay revealed proper survival of the cells of HUVEC cell line on the prepared scaffolds,where the highest percentages were observed for random and aligned PU/Col/Au50 nanofibers.According to the findings,the fabricated PU/Col/AuNPs nanofibrous scaffolds could be considered as potential cardiac patches. 展开更多
关键词 Electrospun nanofiber POLYURETHANE COLLAGEN gold nanoparticles Cardiac patch
暂未订购
Geochemical analysis of organic matter associated with gold in ore deposits:A study of Kazakhstan and Hungary
14
作者 Medet Junussov Asif Mohammad Sotirios Longinos 《Acta Geochimica》 2025年第1期23-35,共13页
This study comprises the relationship between organic matter(OM)and gold occurrence using two distinctive ore deposits of the Bakyrchik gold-sulfide deposit(Kazakhstan)and Western Mecsek uranium ore deposit(Hungary).T... This study comprises the relationship between organic matter(OM)and gold occurrence using two distinctive ore deposits of the Bakyrchik gold-sulfide deposit(Kazakhstan)and Western Mecsek uranium ore deposit(Hungary).The two ore deposits are identified as organicrich sedimentary formations linked to the Variscan gold cycle globally.Characterizing OM is essential because it can act as a carrier for gold,influencing its distribution and behavior within the deposit.Understanding the nature and distribution of OM can provide insights into the processes of gold deposition and help optimize exploration and extraction strategies in mining operations.The primary objective is to characterize OM by identifying its elemental composition,thermal maturity,functional groups,and soluble fractions;and extract gold from OM using a two-step sequential extraction method(hydrogen peroxide and aqua regia)combined with geochemical techniques.Analytical and experimental results from samples of both ore deposits indicate the presence of finely disseminated solid bitumen and reworked vitrinite,originating from thermally matured(RmcRo%—3.76 in Bakyrchik;Ro%—2.25 in W-Mecsek)terrigenous high plants.Both deposits exhibit extremely low extractable bitumen yield and TOC(0.34%in Bakyrchik;0.25 wt%in W-Mecsek),characterized by an aromatic carboxylic acid organic structure and a composition rich in sulfur-containing(1.17%in Bakyrchik;5.81%in W-Mecsek)aromatic hydrocarbons.Gold occurrence and enrichment within OM were confi rmed through the sequential extraction method employing ICP-OES and LA-ICP-MS techniques.The sequentially extracted gold content from OM reached up to 3 ppm in Bakyrchik and up to 3.28 ppm in Western Mecsek,accompanied by Ag(ranging from 0.01 to 0.32 ppm).Higher concentrations of Au(4 ppm)and Ag(27 ppm)were extracted from residue materials,which are likely associated with sulfide minerals.The presence of gold in OM was further validated using LA-ICP-MS.Gold bonding within OM structure,gold is preserved in the form of lattice gold or structurally bonded metal most likely within the aromatic hydrocarbon fractions of the OM in both the W-Mecsek and Bakyrchik deposits.These findings underscore the profound potential of ongoing exploration endeavors,off ering pivotal revelations regarding the extraction and practical application of Au and Ag derived from OM within the geochemical framework of both ore deposits. 展开更多
关键词 Bakyrchik Western Mecsek Solid bitumen Reworked vitrinite gold
在线阅读 下载PDF
Catalytic effect of nano-thick gold electrodes on p-doping of diselenides during annealing process
15
作者 Yan Wang Yang Sun Jing Liu 《Nanotechnology and Precision Engineering》 2025年第3期66-73,共8页
Two-dimensional transition metal dichalcogenides(TMDs)show great promise for developing the next generation of electronic and optoelectronic devices.However,most TMDs have n-type or n-dominant bipolar characteristics,... Two-dimensional transition metal dichalcogenides(TMDs)show great promise for developing the next generation of electronic and optoelectronic devices.However,most TMDs have n-type or n-dominant bipolar characteristics,and this severely limits their potential for being designed as multi-functional heterostructures.Recently,thermal annealing has been reported as an easy means of p-doping TMDs,but the mechanism remains ambiguous,thereby preventing reliable outcomes and it becoming a mature doping technology for TMDs.Here,the mechanism of thermal annealing for p-doping a 2D selenide is investigated thoroughly,revealing the key role of the catalytic effect of nano-thick gold electrodes in achieving p-doping.As an example,2D SnSe_(2)with a fairly high electron density of∼10^(18)cm^(−3)is used,and its electrical performance is greatly enhanced after thermal annealing when 30-nm-thick gold electrodes are deposited.The results of performing XPS and Auger electron spectroscopy on samples before and after annealing show that the p-doping effect is due to the oxidation of selenide atoms,during which the gold acts as a critical catalytic element.This method is also shown to be valid for other 2D selenides including WSe_(2)and MoSe_(2),and the present findings offer new avenues for enriching the electrical properties of 2D selenides by means of annealing. 展开更多
关键词 DISELENIDE Annealing Field-effect transistor(FET) P-DOPING Nano-thick gold Catalytic
在线阅读 下载PDF
Visible-light responsive gold nanoparticle and nano-sized Bi_(2)O_(3-x) sheet heterozygote structure for efficient photocatalytic conversion of N_(2)to NH_(3)
16
作者 Jijoe Samuel Prabagar Kumbam Lingeshwar Reddy Dong-Kwon Lim 《Chinese Journal of Structural Chemistry》 2025年第4期69-79,共11页
The advancement in catalysis techniques for sustainable environmental applications,particularly an alternative to the current Haber-Bosch process for NH_(3),has recently gained widespread attention.Although photocatal... The advancement in catalysis techniques for sustainable environmental applications,particularly an alternative to the current Haber-Bosch process for NH_(3),has recently gained widespread attention.Although photocatalytic conversion of N_(2) to NH_(3) using solar energy is an eco-friendly method,it has the limitation of low quantum yield.Recently,2D Bi-based photocatalysts which exhibit higher visible light absorption than TiO_(2) and higher stability than MXene have been an active research topic,and their performance can be enhanced through improved visible light absorption properties by incorporating plasmonic gold nanoparticles while nitrogen adsorption could be enhanced through oxygen vacancy(OV)processes.In the present study,we explore the application of 2D nanosized Bi_(2)O_(3–x) and gold nanoparticles for visible light photo generation of NH_(3).HRTEM and XPS reveal that the formation of AuNP and nano-sized Bi_(2)O_(3–x) in AuNP/Bi_(2)O_(3–x) heterozygote structure promotes the charge carrier mobility and charge transport at the interface,resulting in a 2.6-fold increase in the photocatalytic activity compared to micro-sized Bi_(2)O_(3–x) with AuNP.The improved photocatalytic performance can be ascribed to significant enhancement of visible light absorption by plasmonic nanoparticles,fast charge transport and mobility(due to sheet morphology)and the N_(2) activation by OV in AuNP/Bi_(2)O_(3–x) heterozygote.Through a systematic experimental investigation involving catalysts,concentration,pH,and scavengers,the highest photocatalytic performance was achieved with the heterozygote structures of AuNP/n-Bi_(2)O_(3–x) under optimized conditions,yielding 432.5μmol gcat^(-1) h^(-1) of NH_(3). 展开更多
关键词 PHOTOCATALYST gold nanoparticle Bismuth oxide Oxygen vacancy Nitrogen fixation
原文传递
A large-scale study on solidification of gold tailings based on microbially induced carbonate precipitation(MICP)
17
作者 Yaoting Duan Qin Yuan +1 位作者 Caiqi Yu Chunli Zheng 《Biogeotechnics》 2025年第3期10-20,共11页
One of the major challenges in the application of microbially induced carbonate precipitation(MICP)is achieving"bacteria freedom",as it necessitates a substantial volume of bacterial solutions.Nevertheless,b... One of the major challenges in the application of microbially induced carbonate precipitation(MICP)is achieving"bacteria freedom",as it necessitates a substantial volume of bacterial solutions.Nevertheless,both insitu bacterial cultivation and transportation of bacterial solutions have proven to be inefficient.In this study,we suggested the utilization of bacteria in the form of dry powder,enabling easy on-site activation and achieving a relatively high urease activity.We conducted MICP curing experiments on gold mine tailings(GMT)using steel slag(SS)as an additive.The results showed that the average unconfined compressive strength(UCS)values of the tailings treated with MICP and MICP+SS reached 0.51 and 0.71 MPa,respectively.In addition,the average leaching reduction rates of Cu,Pb,Cr,Zn,and T-CN in GMT after MICP treatment reached 98.54%,100%,70.94%,59.25%,and 98.02%,respectively,and the average reduction rates after MICP+SS treatment reached 98.77%,100%,88.03%,72.59%,and 98.63%,respectively.SEM,XRD,FT-IR analyses,and ultra-deep field microscopy results confirmed that the MICP treatment produced calcite-based calcium carbonate that filled the inter-tailing pores and cemented them together,and the hydration mechanism was the main reason for the increased curing efficiency of SS.Our research findings demonstrate that bacterial powder can efficiently achieve the objectives of heavy metal removal and tailing solidification.This approach can substantially de-crease the expenses associated with bacterial cultivation and solution transportation,thereby playing a crucial role in advancing the practical implementation of MICP. 展开更多
关键词 gold mine tailings MICP SOLIDIFICATION Bacterial powder
暂未订购
2024 Annual Report of China Mineral Resources (copper, gold, coal, etc.)
18
作者 Li-qiong Jia Xi-jie Chen Zi-guo Hao 《China Geology》 2025年第1期235-236,共2页
In October 2024,the Ministry of Natural Resources of PRC released the 2024 China Mineral Resources Report,which focuses on new progress since 2023 in the geological and mineral survey and evaluation,mineral resource e... In October 2024,the Ministry of Natural Resources of PRC released the 2024 China Mineral Resources Report,which focuses on new progress since 2023 in the geological and mineral survey and evaluation,mineral resource exploration and development,mine ecological restoration,green mine construction,new changes in mineral resource policies and regulations,new measures in mineral resource management,new situations in scientific and technological innovation,as well as the new achievements of the international geological and mineral cooperation. 展开更多
关键词 gold COPPER RESOURCE
在线阅读 下载PDF
Role of Gold Nanorods Functionalized by Nucleic Acid Nanostructures Carrying Doxorubicin in Synergistic Anti-Cancer Therapy
19
作者 Hao Wu Huangshui Ma +5 位作者 Xinghan Wu Qiang Sun Lin Feng Ruifang Jiang Yanhong Li Quan Shi 《Biomedical and Environmental Sciences》 2025年第4期403-415,共13页
Objective Cancer remains a significant global health challenge, necessitating the development of effective treatment approaches. Developing synergistic therapy can provide a highly promising strategy for anti-cancer t... Objective Cancer remains a significant global health challenge, necessitating the development of effective treatment approaches. Developing synergistic therapy can provide a highly promising strategy for anti-cancer treatment through combining the benefits of various mechanisms.Methods In this study, we developed a synergistic strategy for chemo-photothermal therapy by constructing nanocomposites using gold nanorods(GNRs) and tetrahedral framework nucleic acids(tFNA) loaded with the anti-tumor drug doxorubicin(DOX).Results Our in vitro studies have systematically clarified the anti-cancer behaviors of tFNA-DOX@GNR nanocomposites, characterized by their enhanced cellular uptake and proficient lysosomal escape capabilities. It was found that the key role of tFNA-DOX@GNR nanocomposites in tumor ablation is primarily due to their capacity to induce cytotoxicity in tumor cells via a photothermal effect, which generates instantaneous high temperatures. This mechanism introduces various responses in tumor cells, facilitated by the thermal effect and the integrated chemotherapeutic action of DOX. These reactions include the induction of endoplasmic reticulum stress, characterized by elevated reactive oxygen species levels, the promotion of apoptotic cell death, and the suppression of tumor cell proliferation.Conclusion This work exhibits the potential of synergistic therapy utilizing nanocomposites for cancer treatment and offers a promising avenue for future therapeutic strategies. 展开更多
关键词 gold Nanorods Synergistic therapy NANOMATERIALS Anti-tumor therapy
暂未订购
Controllable synthesis of selenolate ligand-costabilized water-soluble near-infrared fluorescent gold nanoclusters for cell imaging
20
作者 Wanxin Li Wenxing Gao +2 位作者 Mengyao Wen Zecheng He Li Shang 《Chinese Chemical Letters》 2025年第10期431-435,共5页
Selenolate ligands are expected to endow fluorescent gold nanoclusters(AuNCs)with better stability and more bioactivity than thiolate ligands,making them promising in the biological field.However,there are few studies... Selenolate ligands are expected to endow fluorescent gold nanoclusters(AuNCs)with better stability and more bioactivity than thiolate ligands,making them promising in the biological field.However,there are few studies on the synthesis of water-soluble selenolate-protected AuNCs,and the impact of selenolate ligands on the optical properties of AuNCs is still unclear.In this study,we synthesized selenolatecostabilized water-soluble,near-infrared fluorescent AuNCs with four different amounts of benzeneselenol(PhSeH),and systematically investigated the role of PhSeH on their optical properties.It is discovered that an appropriate PhSeH content is favorable for the fluorescence enhancement of AuNCs due to the ligand to metal charge transfer effect.Moreover,AuNCs co-stabilized by selenolate ligands exhibit better photostability and long-term stability compared with AuNCs stabilized by thiolate ligands,owing to the introduction of Au-Se bond on their surfaces.Further cellular experiments revealed that selenolate ligands can also affect the cellular uptake efficiency of AuNCs and their imaging property.These results provide important knowledges for further development of new,robust selenolate-stabilized metal NCs for biological application. 展开更多
关键词 gold nanoclusters Fluorescence probes Surface ligands Selenolate ligands Cell imaging
原文传递
上一页 1 2 250 下一页 到第
使用帮助 返回顶部