期刊文献+
共找到151篇文章
< 1 2 8 >
每页显示 20 50 100
Superior adsorption performance of graphitic carbon nitride nanosheets for both cationic and anionic heavy metals from wastewater 被引量:6
1
作者 Gang Xiao Yaoqiang Wang +5 位作者 Shengnan Xu Peifeng Li Chen Yang Yu Jin Qiufeng Sun Haijia Su 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2019年第2期305-313,共9页
Water pollution caused by highly toxic Cd(II), Pb(II), and Cr(VI) is a serious problem. In the present work,a green and low-cost adsorbent of g-C_3N_4 nanosheets was developed with superior capacity for both cationic ... Water pollution caused by highly toxic Cd(II), Pb(II), and Cr(VI) is a serious problem. In the present work,a green and low-cost adsorbent of g-C_3N_4 nanosheets was developed with superior capacity for both cationic and anionic heavy metals. The adsorbent was easily fabricated through one-step calcination of guanidine hydrochloride with thickness less than 1.6 nm and specific surface area of 111.2 m^2·g^(-1). Kinetic and isotherm studies suggest that the adsorption is an endothermic chemisorption process, occurring on the energetically heterogeneous surface based on a hybrid mechanism of multilayer and monolayer adsorption. The tri-s-triazine units and surface N-containing groups of g-C_3N_4 nanosheets are proposed to be responsible for the adsorption process.Further study on pH demonstrates that electrostatic interaction plays an important role. The maximum adsorption capacity of Cd(II), Pb(II), and Cr(VI) on g-C_3N_4 nanosheets is 123.205 mg·g^(-1), 136.571 mg·g^(-1),and 684.451 mg·g^(-1), respectively. The better adsorption performance of the adsorbent than that of the recently reported nanomaterials and low-cost adsorbents proves its great application potential in the removal of heavy metal contaminants from wastewater. The present paper developed a promising adsorbent which will certainly find applications in wastewater treatment and also provides guiding significance in designing adsorption processes. 展开更多
关键词 g-C3n4 nAnOSHEETS nAnOMATERIALS Adsorption heavy metals WASTEWATER
下载PDF
Determination of Inorganic Elements in Paris daliensis H.Li et V.G.Souku and Paris dulongensis H.Li et S.Kuritap by ICP-OES 被引量:1
2
作者 Jixiu SHEN Zhongjie HUANG +3 位作者 Risha WEIZE Xuexue LI Yunzhang XU Yuan LIU 《Medicinal Plant》 CAS 2019年第1期37-39,共3页
[Objectives] To determine 29 kinds of inorganic elements in samples of Paris daliensis H.Li et V.G.Souku and P. dulongensis H.Li et S.Kuritap produced in different regions, and to measure the content of 10 key inorgan... [Objectives] To determine 29 kinds of inorganic elements in samples of Paris daliensis H.Li et V.G.Souku and P. dulongensis H.Li et S.Kuritap produced in different regions, and to measure the content of 10 key inorganic elements: chromium(Cr), manganese(Mn), iron(Fe), copper(Cu), mercury(Hg), zinc(Zn), arsenic(As), antimony(Sr), cadmium(Cd) and lead(Pb). [Methods] The wet digestion and technique of inductively coupled plasma optical emission spectrometry(ICP-OES) were employed. [Results] Under the experimental conditions, elements were not related to each other, and many kinds of elements could be measured at the same time; toxic and heavy metals in samples of P. daliensis H.Li et V.G.Souku and P. dulongensis H.Li et S.Kuritap did not exceed the limit; Hg was not detected in all samples. [Conclusions] This method is simple, easy to operate and reproducible. It can be used for the detection of inorganic elements in P. daliensis H.Li et V.G.Souku and P. dulongensis H.Li et S.Kuritap; the heavy metals and Hg of the rhizome meet the requirements of the limit of medicinal materials. 展开更多
关键词 pARIS daliensis H.Li ET V.G.Souku p.dulongensis H.Li ET S.Kuritap Inorganic element Wet DIGESTIOn Inductively coupled plasma optical emission spectrometry(ICp-OES) heavy metals
下载PDF
Concentration and Biomagnification of Heavy Metals in Biota of the Coastal Marine Areas of Tanzania
3
作者 Sharifa Omar Bungala, John Ferdinand Machiwa and Daniel Abel Shilla 《Journal of Environmental Science and Engineering(B)》 2017年第8期406-424,共19页
The concentrations of heavy metals (As, Hg, Cr, Pb and Zn) were measured in the macroalgae, macrobenthos and fish from the Tanzanian coastal marine environment in order to ascertain the biomagnification using stable... The concentrations of heavy metals (As, Hg, Cr, Pb and Zn) were measured in the macroalgae, macrobenthos and fish from the Tanzanian coastal marine environment in order to ascertain the biomagnification using stable isotopes of C and N. Macroalgae samples from the central marine areas of the Tanzanian coast had higher mean concentrations of Hg (0.17 ± 0.01 μg/g) and Cr (23.7 ± 4.15 μg/g) compared to other locations. Higher concentration of Hg (0.06 ±0.02 μg/g) was detected in the Ulva fasciata close to the Msimbazi Creek in Dares Salaam, whereas the highest concentration of Cr (45.5 ± 6.83 μg/g) was found in Ulva petrusa near Dares Salaam port. The crab Portunus pelagicus collected from Pangani river estuary contained 411.5 ± 13.04 μg/g of Zn. The other metals were uniformly distributed in macrobenthos from the entire coast. Mercury and lead in the biota were found to biomagnify along the Arius dussumieri and Lethrinus lentjan food chains as suggested by the significant positive relationships between log-pollutant concentrations in fish muscle tissues vs. 615N signatures. Zinc in muscle tissues was found to be transferred along the food webs although no biomagnification was observed. Arsenic and chromium were found to decrease with the rise of the trophic position. Metal concentrations in macroalgae, macrobenthos and fish were compared with quality guidelines values by FAO (Food and Agricultural Organization) in 1983 and they all were below permissible limits for human consumption.δ 展开更多
关键词 heavy metals food chains BIOCOnCEnTRATIOn BIOMAGnIFICATIOn stable isotope ratios δ13C δ15n TL (Trophic Level).
下载PDF
p-Si/n-Ga_(2)O_(3)异质结制备与特性研究
4
作者 陈沛然 焦腾 +6 位作者 陈威 党新明 刁肇悌 李政达 韩宇 于含 董鑫 《人工晶体学报》 北大核心 2024年第1期73-81,共9页
本实验采用金属有机化学气相沉积(MOCVD)工艺,在p(111)型Si衬底上制备了p-Si/n-Ga_(2)O_(3)结构的PN结。通过X射线衍射仪、原子力显微镜等对样品进行了晶体结构、表面形貌、表面粗糙度等的表征分析;通过磁控溅射与蒸镀方法在样品上生长T... 本实验采用金属有机化学气相沉积(MOCVD)工艺,在p(111)型Si衬底上制备了p-Si/n-Ga_(2)O_(3)结构的PN结。通过X射线衍射仪、原子力显微镜等对样品进行了晶体结构、表面形貌、表面粗糙度等的表征分析;通过磁控溅射与蒸镀方法在样品上生长Ti/Au电极并进行I-V特性曲线、开启电压、开关电流比、反向饱和电流、理想因子、零偏压下的势垒高度等结特性测试,研究了掺杂浓度与薄膜厚度对PN结特性的影响,并对其原因进行了分析;通过二步生长法和缓冲层温度优化实验,减少了Si衬底与β-Ga_(2)O_(3)之间的晶格失配与热失配带来的影响,对薄膜与器件特性进行了优化。最终获得了表面粗糙度最低可达到4.21 nm的高质量n型β-Ga_(2)O_(3)薄膜,以及具有较低理想因子(42.1)的PN结。 展开更多
关键词 β-Ga_(2)O_(3)薄膜 金属有机化学气相沉积 p-Si/n-Ga_(2)O_(3) pn 晶体质量 电学特性
下载PDF
Effect of Combined Heavy Metal Pollution on Nitrogen Mineralization Potential,Urease and Phosphatase Activities in a Typic Udic Ferrisol 被引量:13
5
作者 ZHENG CHUNRONG TU CONG and CHEN HUAIMAN(Laboratory of Material Cycling in Pedosphere, Institute of Soil Science, the Chinese Academy of Sciences,Nanjing 210008 (China))(Received April 20, 1999 revised June 2, 1999) 《Pedosphere》 SCIE CAS CSCD 1999年第3期251-258,共8页
Individual and combined effects of Cu, Pb, Zn and Cd on N mineralization, urease and phosphatase were examined in a Typic Udic Ferrisol in laboratory by employing an uniform design and a single factor design.Soil poll... Individual and combined effects of Cu, Pb, Zn and Cd on N mineralization, urease and phosphatase were examined in a Typic Udic Ferrisol in laboratory by employing an uniform design and a single factor design.Soil pollution caused by heavy metals inhibited N mineralization (No value) and urease and phosphatase activities. The combined pollution of metals alleviated their toxicity to N mineralization to some extent,whereas aggravated the toxicity to urease and phosphatase. Phosphorous application could mitigate the toxic effect of heavy metals on phosphatase activities, while alleviating effect of N application on the toxicity of heavy metals to urease was inconsistent. However, the mitigating effect of the fertilizers was limited in heavily polluted soils. 展开更多
关键词 heavy metal pollution n mineralization pHOSpHATASE UREASE
下载PDF
A New Thioamide Derivative for Separation and Preconcentration of Multi Elements in Aquatic Environment by Cloud Point Extraction 被引量:1
6
作者 Mohamed M. Hassanien Ali M. Hassan +1 位作者 Wael I. Mortada Ahmed A. El-Asmy 《American Journal of Analytical Chemistry》 2011年第6期697-709,共13页
2-(pyridine-2-yl)-N-p-chlorohydrazinecarbothioamide (HCPTS) was synthesized, characterized and successfully applied for the preconcentration of Cu(II), Ni(II), Zn(II), Cd(II), Co(II), Pb(II), Fe(II), and Hg(II) in wat... 2-(pyridine-2-yl)-N-p-chlorohydrazinecarbothioamide (HCPTS) was synthesized, characterized and successfully applied for the preconcentration of Cu(II), Ni(II), Zn(II), Cd(II), Co(II), Pb(II), Fe(II), and Hg(II) in water, blood, and urine samples prior to graphite furnace atomic absorption determination (GFAAS);Hg was determined by cold vapor technique. Under the optimum experimental conditions (i.e. pH = 8, 10–4 M of HCPTS, 0.05% w/v of Triton X-114), calibration graphs were linear in the range of 0.02 to 200 ng?mL–1 for Co(II), Cd(II), Pb(II) and Ni(II);0.03 to 200 ng?mL–1 for Cu(II);0.07 to 200 ng?mL–1 for Fe(II) and Zn(II) and 0.02 to 150 ng?mL–1 for Hg(II). The enrichment factors were 43, 51, 41, 46, 54, 40, 45 and 52 for Cu(II), Ni(II),Zn (II), Cd(II), Co(II), Pb(II), Fe(II), and Hg(II), respectively. The limit of detection were found to be 0.019, 0.094, 0.0514, 0.052, 0.0165, 0.047, 0.068 and 0.041 ng?mL–1 for Cu(II), Ni(II), Zn(II), Cd(II), Co(II), Pb(II), Fe(II), and Hg(II), respectively. The developed method was applied to the determination of these metal ions in water, blood and urine samples with satisfactory results. 展开更多
关键词 heavy metals pRECOnCEnTRATIOn Cloud point Extraction 2-(pyridine-2-Yl)-n-p-Chlorohydrazinecarbothioamide
下载PDF
Effects of metal lead on growth and mycorrhizae of an invasive plant species (Solidago canadensis L.) 被引量:14
7
作者 YANG Ruyi YU Guodong +1 位作者 TANG Jianjun CHEN Xin 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2008年第6期739-744,共6页
It is less known whether and how soil metal lead (Pb) impacts the invasion of exotic plants. A greenhouse experiment was conducted to estimate the effects of lead on the growth and mycorrhizae of an invasive species... It is less known whether and how soil metal lead (Pb) impacts the invasion of exotic plants. A greenhouse experiment was conducted to estimate the effects of lead on the growth and mycorrhizae of an invasive species (Solidago canadensis L.) in a microcosm system. Each microcosm unit was separated into HOST and TEST compartments by a replaceable mesh screen that allowed arbuscular mycorrhizal (AM) fungal hyphae rather than plant roots to grow into the TEST compartments. Three Pb levels (control, 300, and 600 mg/kg soil) were used in this study to simulate ambient soil and two pollution sites where S. canadensis grows. Mycorrhizal inoculum comprised five indigenous arbuscular mycorrhizal fungal species ( Glomus mosseae, Glomus versiform, Glomus diaphanum, Glomus geosporum, and Glomus etunicatum). The ^15N isotope tracer was used to quantify the mycorrhizally mediated nitrogen acquisition of plants. The results showed that S. canadensis was highly dependent on mycorrhizae. The Pb additions significantly decreased biomass and arbuscular mycorrhizal colonization (root length colonized, RLC%) but did not affect spore numbers, N (including total N and ^15N) and P uptake. The facilitating efficiency of mycorrhizae on nutrient acquisition was promoted by Pb treatments. The Pb was mostly sequestered in belowground of plant (root and rhizome). The results suggest that the high efficiency of mycorrhizae on nutrient uptake might give S. canadensis a great advantage over native species in Pb polluted soils. 展开更多
关键词 Solidago canadensis L. metal lead MYCORRHIZAE n and p uptake pb accumulation
下载PDF
Effects of the heavy metal cadmium on photosynthetic activity and the xanthophyll cycle in Phaeodactylum tricornutum
8
作者 JI Yan XIE Xiujun WANG Guangce 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2018年第6期2194-2201,共8页
A bstract Cadmium(Cd) is one of the most common and widespread heavy metals in the environment. Cd has adverse effects on photosynthesis that are countered by photosystem I(PSI) and photosystem II(PSII); however, the ... A bstract Cadmium(Cd) is one of the most common and widespread heavy metals in the environment. Cd has adverse effects on photosynthesis that are countered by photosystem I(PSI) and photosystem II(PSII); however, the protective responses of these photosystems to heavy metal stress remain unclear. Using the model diatom P haeodactylum tricornutum, a biological indicator that is widely used to assess the impact of environmental toxins, we simultaneously measured the effects of Cd on PSI and PSII and examined the levels of pigments in response to high light treatments before and after Cd exposure. Cd significantly reduced the quantum yield and electron transport rates of PSI and PSII. The quantum yield of non-photochemical energy dissipation in PSI due to donor side limitation increased faster than the quantum yield due to acceptor side limitation. The Cd treatment activated the P. tricornutum xanthophyll cycle under artificial light conditions, as indicated by an increased diatoxanthin content. Xanthophyll is important for photoprotection; therefore, the accumulation of diatoxanthin may down-regulate PSII activities to reduce oxidative damage. Together, our results suggest that the rapid reduction in PSII activities following Cd exposure is an adaptive response to heavy metal stress that reflects the variable exposure to external stressors in the native P. tricornutum environment. 展开更多
关键词 heavy metal CADMIUM photosystemⅠ photosystemⅡ pHAEODACTYLUM TRICORnUTUM
下载PDF
MnO_(2) nanosheet modified N, P co-doping carbon nanofibers on carbon cloth as lithiophilic host to construct high-performance anodes for Li metal batteries
9
作者 Xiaoqiang Liu Qian Zhang +6 位作者 Yiru Ma Zhenzhen Chi Huixiang Yin Jie Liu Junfei Huang Ziyang Guo Lei Wang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2022年第6期270-281,I0008,共13页
Lithium (Li) metal batteries have attracted much attention owing to its ultra-high energy density.However,as important part of Li metal batteries,Li anodes still face many challenges,mainly including uncontrolled dend... Lithium (Li) metal batteries have attracted much attention owing to its ultra-high energy density.However,as important part of Li metal batteries,Li anodes still face many challenges,mainly including uncontrolled dendritic Li formation,dramatical volume variation and serious pulverization.Herein,manganese dioxide (MnO_(2)) nanosheet modified nitrogen (N),phosphorus (P) co-doping carbon nanofibers(NPC) on carbon cloth (CC)(MnO_(2)@NPC-CC) is successfully fabricated through electrodeposition approach and further treated with Li by the molten-infusion method to prepare Li based Mn@NPC-CC(Li-Mn@NPC-CC) electrode.The synergy of MnO_(2) and NPC obviously increases the reaction rate between MnO_(2)@NPC-CC and Li and guides even Li distribution over infusion process.Additionally,theoretical calculation,simulation and experimental results further indicate that N,P,Mn multi-doping effectively improves the superior lithiophilicity of Li-Mn@NPC-CC,which induces uniform Li deposition/dissolution to suppress dendrite growth over cycles.Moreover,conductive and porous NPC matrix not only effectively improves the stability of Li-Mn@NPC-CC,but also provides abundant spaces to accelerate the transfer of ion/electron and buffer electrode dimension variation during cycling.Hence,Li-Mn@NPC-CC-based symmetric cells exhibit extra-long cycling life (over 2200 h) with small hysteresis of 20 mV.When the LiMn@NPC-CC anode couples with air,Li iron phosphate (LiFePO_(4)),or hard carbon (C) cathode,the assembled full cells exhibit outstanding performance with low hysteresis and stable cycling properties.Especially,the corresponding pouch-typed Li–air cells also exhibit good performance at different bending angles and even power a series of electronic devices. 展开更多
关键词 n p co-doped carbon nanofibers on carbon cloth MnO_(2)nanosheet coating Molten-infusion method Li metal anodes Li metal batteries
下载PDF
High-performance germanium n+/p junction by nickel-induced dopant activation of implanted phosphorus at low temperature
10
作者 黄巍 陆超 +9 位作者 余珏 魏江镔 陈超文 汪建元 徐剑芳 王尘 李成 陈松岩 刘春莉 赖虹凯 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第5期312-315,共4页
High-performance Ge n~+/p junctions were fabricated at a low formation temperature from 325℃ to 400℃ with a metal(nickel)-induced dopant activation technique. The obtained Ni Ge electroded Ge n+/p junction has a... High-performance Ge n~+/p junctions were fabricated at a low formation temperature from 325℃ to 400℃ with a metal(nickel)-induced dopant activation technique. The obtained Ni Ge electroded Ge n+/p junction has a rectification ratio of 5.6×10~4 and a forward current of 387 A/cm^2at -1 V bias. The Ni-based metal-induced dopant activation technique is expected to meet the requirement of the shallow junction of Ge MOSFET. 展开更多
关键词 GERMAnIUM metal-induced dopant activation niGe n+/p junction
下载PDF
The Growth Characteristics of Three Terrestrial Plants Cultivated with Biogas Slurry as a Hydroponic Medium
11
作者 Qun Kang Jinhui Zhao +3 位作者 Pan Zhu Qin Gong Ling Wang Zhaohua Li 《American Journal of Plant Sciences》 2020年第6期819-831,共13页
Biogas slurry is a traditional high-quality organic liquid fertilizer. Three terrestrial plants with high economic value, fu </span><span style="font-family:Verdana;">gui</span> <span st... Biogas slurry is a traditional high-quality organic liquid fertilizer. Three terrestrial plants with high economic value, fu </span><span style="font-family:Verdana;">gui</span> <span style="font-family:Verdana;">cai</span><span style="font-family:Verdana;">, yang </span><span style="font-family:Verdana;">xin</span> <span style="font-family:Verdana;">cai</span> <span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> strawberry, were selected for hydroponic cultivation using an optimal dilution of biogas slurry. The results of the experiments showed that strawberries could bloom and bear fruit and fu </span><span style="font-family:Verdana;">gui</span> <span style="font-family:Verdana;">cai</span><span style="font-family:Verdana;"> and yang </span><span style="font-family:Verdana;">xin</span> <span style="font-family:Verdana;">cai</span><span style="font-family:Verdana;"> grew well. However, in comparison with the control groups planted in soil, all three crops were subject to a certain degree of environmental stress, as shown by changes in growth, biomass indicators, physiological indicators </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> morphological indicators. The leaves and stems of yang </span><span style="font-family:Verdana;">cai</span><span style="font-family:Verdana;"> and fu </span><span style="font-family:Verdana;">gui</span> <span style="font-family:Verdana;">cai</span><span style="font-family:Verdana;"> were tested for several types of heavy metals, and all met the requirements for human consumption. It is feasible to cultivate these three plants with biogas slurry. The results of this study can help guide hydroponic production practices and have practical significance and reference value. 展开更多
关键词 Biogas Slurry Fu Gui Cai Yang Xin Cai STRAWBERRY n/p/K Vitamin C CHLOROpHYLL heavy metals
下载PDF
半导体硅片的p-n结和铜沉积行为的电化学研究 被引量:9
12
作者 程璇 林昌健 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2000年第5期509-516,共8页
分别采用电化学直流极化和交流阻抗技术 ,通过控制光照和溶液化学组分 ,研究了半导体硅片 /氢氟酸体系的电化学特性和半导体性能 .对 p( 1 0 0 )和 n( 1 0 0 )两种硅片的研究结果均表明 ,有光照条件下硅 /氢氟酸界面上的电化学反应很容... 分别采用电化学直流极化和交流阻抗技术 ,通过控制光照和溶液化学组分 ,研究了半导体硅片 /氢氟酸体系的电化学特性和半导体性能 .对 p( 1 0 0 )和 n( 1 0 0 )两种硅片的研究结果均表明 ,有光照条件下硅 /氢氟酸界面上的电化学反应很容易发生且起着主导作用 ,而黑暗条件下硅片则处于消耗期 ,电化学反应难于发生 ,因而其半导体性能起着重要的作用 .当溶液中有微量铜存在时 ,硅 /溶液界面上的电化学反应将被加速 .通过单独研究两种硅片的电化学行为 ,讨论了半导体硅片在氢氟酸溶液中形成的 p- n接点行为 ,并通过考察溶液中的铜离子浓度、光照条件和沉积时间对铜在硅片上的沉积行为的影响 ,探讨了铜沉积机理 .研究结果表明 ,电化学交流阻抗法对研究稀释氢氟酸溶液中 ppb浓度水平的微量铜杂质对硅片表面的污染极为有效 。 展开更多
关键词 铜沉积 半导体硅片 p-n 电化学
下载PDF
小尺度下农田潮土Olsen-P的空间分布及其与重金属的关系 被引量:2
13
作者 邢维芹 李立平 +3 位作者 李红伟 周慧芳 白瑞 朱磊 《西北农业学报》 CAS CSCD 北大核心 2010年第2期122-126,共5页
玉米收获后以10 cm×10 cm网格采取1.0 m×1.0 m范围内0-20 cm土样,测定Olsen-P含量、DTPA提取态和全量Cu、Mn、Pb和Zn,并研究磷与重金属的相关性。结果表明,土壤Olsen-P的变化范围为3.3-38.5 mg/kg,平均值为9.6 mg/kg,变异系数... 玉米收获后以10 cm×10 cm网格采取1.0 m×1.0 m范围内0-20 cm土样,测定Olsen-P含量、DTPA提取态和全量Cu、Mn、Pb和Zn,并研究磷与重金属的相关性。结果表明,土壤Olsen-P的变化范围为3.3-38.5 mg/kg,平均值为9.6 mg/kg,变异系数为49.87%;Olsen-P在采样区的南北边缘含量较高,空间变异是结构性因素和随机因素共同作用的结果;Olsen-P与DTPA态Cu和Pb之间存在极显著负相关(P〈0.01),与DTPA态Mn和Zn的相关性不显著(P〉0.05),全量Mn、Pb和Zn与Olsen-P之间呈极显著正相关(P〈0.01)。以上结果说明,玉米生长期间追施水溶性磷肥导致土壤Olsen-P的空间变异发生变化,磷肥施用导致部分Cu和Pb有效性下降、全Mn、全Pb和全Zn含量上升。 展开更多
关键词 OLSEn-p 空间分布 重金属 潮土 小尺度 玉米 华北平原
下载PDF
高低周复合载荷下的P-S-N曲线研究 被引量:4
14
作者 王时越 李建云 刘其勇 《昆明理工大学学报(理工版)》 2006年第2期90-92,共3页
在高低周复合载荷作用下,对45钢进行了5级应力水平下的疲劳寿命试验,并对试验结果进行了统计分析,得出了P-N图和P-S-N曲线.结果表明:高低周复合疲劳寿命满足对数正态分布,每级应力水平下疲劳寿命的分散程度相同.
关键词 p-S-n曲线 金属疲劳 疲劳断裂
下载PDF
Heavy metal contents in soil of major towns in the east coast of Peninsular Malaysia 被引量:1
15
作者 Seng Chee Poh Norhaxati Mohd Tahir +3 位作者 Hafiza Mohamed Zuki Mohd Izwadi Musa Khai Hock Ng Noor Azhar Mohamed Shazili 《Chinese Journal Of Geochemistry》 EI CAS 2006年第B08期56-56,共1页
关键词 城市土壤 重金属 环境污染 原子吸收光谱法
下载PDF
功率器件用n/p型4H-SiC同时形成欧姆接触工艺 被引量:2
16
作者 夏经华 桑玲 +7 位作者 杨香 郑柳 查祎英 田亮 田丽欣 张文婷 杨霏 吴军民 《微纳电子技术》 北大核心 2020年第7期568-576,共9页
综述了在n/p型4H-SiC上同时形成欧姆接触技术的研究进展,包括欧姆接触理论、欧姆接触工艺及其优缺点以及热稳定性/可靠性等方面。重点介绍了基于Ni基金属的n/p型4H-SiC同时形成欧姆接触的工艺,包括以金属Ni为基础并结合Ti和Al与W等金属... 综述了在n/p型4H-SiC上同时形成欧姆接触技术的研究进展,包括欧姆接触理论、欧姆接触工艺及其优缺点以及热稳定性/可靠性等方面。重点介绍了基于Ni基金属的n/p型4H-SiC同时形成欧姆接触的工艺,包括以金属Ni为基础并结合Ti和Al与W等金属所形成的各种复合接触材料、通过合适的合金化退火工艺后得到的合金相、形成欧姆接触后得到的比接触电阻率,讨论了可能的欧姆接触形成机理,评估了其热稳定性/可靠性。讨论了在工艺上增加保护层对Ni基n/p型4H-SiC欧姆接触的性能以及热稳定性/可靠性等性能的影响。最后,评估了该工艺的研发现状和存在的问题,并提出未来的展望。 展开更多
关键词 n/p型4H-SiC ni基金属 同时形成欧姆接触 欧姆接触机理 合金相
下载PDF
螺旋埋弧焊接X70钢管焊缝金属P-S-N曲线的建立 被引量:1
17
作者 郑新侠 雒设计 《机械工程材料》 CAS CSCD 北大核心 2016年第7期56-59,63,共5页
通过对螺旋埋弧焊接X70钢管焊缝金属进行疲劳试验,得到了不同应力幅和应力比下的疲劳寿命数据,对疲劳寿命的概率分布进行了分析;依据当量疲劳寿命公式,获得疲劳抗力系数和当量疲劳极限,并对其概率分布进行分析,进而建立了焊缝金属的P-S-... 通过对螺旋埋弧焊接X70钢管焊缝金属进行疲劳试验,得到了不同应力幅和应力比下的疲劳寿命数据,对疲劳寿命的概率分布进行了分析;依据当量疲劳寿命公式,获得疲劳抗力系数和当量疲劳极限,并对其概率分布进行分析,进而建立了焊缝金属的P-S-N曲线,给出了指定存活率下的疲劳寿命曲线。结果表明:焊缝金属的疲劳寿命服从对数正态分布,疲劳抗力系数服从对数正态分布,以当量应力表示的疲劳极限服从正态分布。 展开更多
关键词 疲劳寿命 概率分布 p-S-n曲线 焊缝金属 X70钢
下载PDF
Boron and nitrogen co-doped porous carbon derived from sodium alginate enhanced capacitive deionization for water purification
18
作者 Xiao Yong Pengfei Sha +5 位作者 Jinghui Peng Mengdi Liu Qian Zhang Jianhua Yu Liyan Yu Lifeng Dong 《Frontiers of Chemical Science and Engineering》 SCIE EI CSCD 2023年第12期2014-2024,共11页
Capacitive deionization can alleviate water shortage and water environmental pollution, but performances are greatly determined by the electrochemical and desalination properties of its electrode materials. In this wo... Capacitive deionization can alleviate water shortage and water environmental pollution, but performances are greatly determined by the electrochemical and desalination properties of its electrode materials. In this work, B and N co-doped porous carbon with micro-mesoporous structures is derived from sodium alginate by a carbonization, activation, and hydrothermal doping process, which exhibits large specific surface area (2587 m^(2)·g^(‒1)) and high specific capacitance (190.7 F·g^(‒1)) for adsorption of salt ions and heavy metal ions. Furthermore, the materials provide a desalination capacity of 26.9 mg·g−1 at 1.2 V in 500 mg·L^(‒1) NaCl solution as well as a high removal capacity (239.6 mg·g^(‒1)) and adsorption rate (7.99 mg·g^(‒1)·min^(‒1)) for Pb2+ with an excellent cycle stability. This work can pave the way to design low-cost porous carbon with high-performances for removal of salt ions and heavy metal ions. 展开更多
关键词 capacitance deionization porous carbon B n co-doping heavy metal ions water purification
原文传递
紫外光控制的金属硫化物/聚苯胺p-n结及其在光敏传感器中的应用 被引量:3
19
作者 杨圣雪 龚剑 +1 位作者 李京波 夏建白 《发光学报》 EI CAS CSCD 北大核心 2013年第11期1413-1418,共6页
设计了由金属硫化物/聚苯胺p-n异质结和紫外光敏材料氧化锌所组成的光敏传感器,通过紫外光照外接氧化锌层来控制金属硫化物/聚苯胺p-n结的耗尽区厚度。与其他报道的光敏材料不同的是,其他光敏材料在紫外光照射下光电导会增加,而该光敏... 设计了由金属硫化物/聚苯胺p-n异质结和紫外光敏材料氧化锌所组成的光敏传感器,通过紫外光照外接氧化锌层来控制金属硫化物/聚苯胺p-n结的耗尽区厚度。与其他报道的光敏材料不同的是,其他光敏材料在紫外光照射下光电导会增加,而该光敏传感器在紫外光照射下光电导会减少。 展开更多
关键词 紫外光控制 金属硫化物 聚苯胺 p-n 光敏传感器
下载PDF
p-n型CuO/α-Fe_2O_3复合半导体材料的制备与气敏性能研究 被引量:2
20
作者 秦聪 王燕 +1 位作者 陈泽华 孙广 《郑州大学学报(工学版)》 CAS 北大核心 2017年第1期87-91,共5页
采用化学沉淀法制备了纯态CuO和α-Fe_2O_3颗粒,并采用沉积-沉淀法将p型半导体CuO负载到n型半导体α-Fe_2O_3表面,制备了p-n型复合半导体氧化物气体敏感材料CuO/α-Fe_2O_3.对所合成的材料进行了XRD、SEM、TEM和XPS表征.结果显示:负载... 采用化学沉淀法制备了纯态CuO和α-Fe_2O_3颗粒,并采用沉积-沉淀法将p型半导体CuO负载到n型半导体α-Fe_2O_3表面,制备了p-n型复合半导体氧化物气体敏感材料CuO/α-Fe_2O_3.对所合成的材料进行了XRD、SEM、TEM和XPS表征.结果显示:负载量较低时,CuO高分散在α-Fe_2O_3载体表面,当负载量达到30%时,形成了新的CuFe_2O_4晶相;所合成的样品由粒径大小约10 nm的纳米颗粒组成.气敏性能测试结果显示:该材料在100℃的较低温度下,对CO的灵敏度相对纯α-Fe_2O_3提高了几十倍. 展开更多
关键词 p-n CuO/α-Fe2O3 复合氧化物 CO 气敏材料
下载PDF
上一页 1 2 8 下一页 到第
使用帮助 返回顶部