期刊文献+
共找到338篇文章
< 1 2 17 >
每页显示 20 50 100
Flexible Gd‑MOF@PMMA/BMA composite film fluorescent sensor for highly sensitive detection of tyramine in bananas
1
作者 ZHANG Xin JIAO Xinyi +4 位作者 BAI Wanqiao SUN Xuehua CUI Huali REN Yixia CHAI Hongmei 《无机化学学报》 北大核心 2026年第2期217-226,共10页
In this study,using 3,5‑di(3′,5′‑dicarboxylphenyl)‑1H‑1,2,4‑triazole(H4L)as ligands,a gadolinia‑based organic framework complex{[GdNa(L)(H_(2)O)3]·2H_(2)O}_(n)(Gd‑Na‑MOF)was successfully designed and synthesize... In this study,using 3,5‑di(3′,5′‑dicarboxylphenyl)‑1H‑1,2,4‑triazole(H4L)as ligands,a gadolinia‑based organic framework complex{[GdNa(L)(H_(2)O)3]·2H_(2)O}_(n)(Gd‑Na‑MOF)was successfully designed and synthesized by hydrothermal method.The structure and properties were systematically characterized and tested by techniques such as single‑crystal X‑ray diffraction,powder X‑ray diffraction,thermogravimetric analysis,infrared spectroscopy,and fluorescence spectroscopy.The results indicate that this complex has a unique 3D structure,excellent thermal stability,and outstanding luminescent performance.Based on its luminescent properties,a polymer‑embedding method was employed to fabricate the Gd‑Na‑MOF into a flexible,washable composite fluorescent film,Gd‑Na‑MOF@PMMA/BMA(PMMA=polymethyl methacrylate,BMA=butyl methacrylate).This fluorescent film exhibited highly sensitive recognition capability for tyramine,with a low detection limit of 1.66μmol·L^(-1).It was used for the detection of tyramine in bananas,with a recovery rate of 96.92%‑100.26%.CCDC:2466949. 展开更多
关键词 metal‑organic frameworks Gd‑Na‑MOF@PMMA/BMA composite fluorescent film fluorescent sensing TYRAMINE
在线阅读 下载PDF
A three-dimensional zinc(Ⅱ)metal-organic framework based on nitrogen-containing ligands for the detection of 2,4-dinitrophenylhydrazine and tetracycline
2
作者 WANG Xuetian WANG Jijiang +3 位作者 TANG Long YUE Erlin WANG Xiao ZHANG Yuqi 《无机化学学报》 北大核心 2026年第4期861-871,共11页
A metal-organic framework{[Zn(L)_(0.5)(1,2,4,5-tpb)_(0.5)]·DMF·3H_(2)O}_(n)(1)was synthesized by solvothermal reaction,where H4L=5,5'-(ethane-1,2-diyl)diisophthalic acid,and 1,2,4,5-tpb=1,2,4,5-tetra(pyr... A metal-organic framework{[Zn(L)_(0.5)(1,2,4,5-tpb)_(0.5)]·DMF·3H_(2)O}_(n)(1)was synthesized by solvothermal reaction,where H4L=5,5'-(ethane-1,2-diyl)diisophthalic acid,and 1,2,4,5-tpb=1,2,4,5-tetra(pyridin-4-yl)benzene.The analysis of the single crystal structure indicates that L^(4-)and 1,2,4,5-tpb are connected with Zn(Ⅱ)to form a 2D layered structure,and the layers are linked by 1,2,4,5-tpb to form a 3D structure.1 can be used as a highly selective fluorescent probe for the detection of 2,4-dinitrophenylhydrazine(DNP)and tetracycline(TET),and the detection limits were 0.013 and 0.31μmol·L^(-1),respectively.1 was applied successfully to the determination of TET content in the Yanhe River water sample.CCDC:2466221. 展开更多
关键词 metal-organic frameworks Zn(Ⅱ) crystal structure fluorescent sensing
在线阅读 下载PDF
Status and Development of Rapid Detection Technology for Tunnel Structural Defects 被引量:6
3
作者 LIU Xuezeng FANG Maoliu +3 位作者 WU Dexing LI Yinping LIU Xingen LI Gang 《隧道建设(中英文)》 北大核心 2025年第4期657-676,I0005-I0024,共40页
Based on inspection data,the authors analyze and summarize the main types and distribution characteristics of tunnel structural defects.These defects are classified into three types:surface defects,internal defects,an... Based on inspection data,the authors analyze and summarize the main types and distribution characteristics of tunnel structural defects.These defects are classified into three types:surface defects,internal defects,and defects behind the structure.To address the need for rapid detection of different defect types,the current state of rapid detection technologies and equipment,both domestically and internationally,is systematically reviewed.The research reveals that surface defect detection technologies and equipment have developed rapidly in recent years.Notably,the integration of machine vision and laser scanning technologies have significantly improved detection efficiency and accuracy,achieving crack detection precision of up to 0.1 mm.However,the non-contact rapid detection of internal and behind-the-structure defects remains constrained by hardware limitations,with traditional detection remaining dominant.Nevertheless,phased array radar,ultrasonic,and acoustic vibration detection technologies have become research hotspots in recent years,offering promising directions for detecting these challenging defect types.Additionally,the application of multisensor fusion technology in rapid detection equipment has further enhanced detection capabilities.Devices such as cameras,3D laser scanners,infrared thermal imagers,and radar demonstrate significant advantages in rapid detection.Future research in tunnel inspection should prioritize breakthroughs in rapid detection technologies for internal and behind-the-structure defects.Efforts should also focus on developing multifunctional integrated detection vehicles that can simultaneously inspect both surface and internal structures.Furthermore,progress in fully automated,intelligent systems with precise defect identification and real-time reporting will be essential to significantly improve the efficiency and accuracy of tunnel inspection. 展开更多
关键词 TUNNEL structural defect inspection techniques inspection equipment rapid inspection
在线阅读 下载PDF
利用Zn掺杂制备高效稳定工业级电解水的NiBP微球催化剂研究
4
作者 Sumiya Akter Dristy Md Ahasan Habib +5 位作者 Shusen Lin Mehedi Hasan Joni Rutuja Mandavkar Young-Uk Chung Md Najibullah Jihoon Lee 《物理化学学报》 北大核心 2025年第7期125-138,共14页
在未来的能源系统中,绿氢具有巨大的应用潜力。设计非贵金属电催化剂对于电解水制氢至关重要,尤其是对于工业级电流密度电解水的实际应用。本文通过水热和电化学方法以及焙烧相结合的多步制备方法,制备得到Zn掺杂的NiBP微球电催化剂(Zn/... 在未来的能源系统中,绿氢具有巨大的应用潜力。设计非贵金属电催化剂对于电解水制氢至关重要,尤其是对于工业级电流密度电解水的实际应用。本文通过水热和电化学方法以及焙烧相结合的多步制备方法,制备得到Zn掺杂的NiBP微球电催化剂(Zn/NiBP)。该催化剂在1 mol·L^(−1)KOH电解质溶液中,电流密度为100 mA·cm^(−2),析氢反应(HER)和析氧反应(OER)的过电位分别为95 mV和280 mV,性能优于之前报道的大多数催化剂。当Zn/NiBP为双功能的阴极和阳极催化剂,在1 mol·L^(−1)KOH溶液中,电流密度达到2000 mA·cm^(−2),电解电压为3.10 V,优于Pt/C||RuO_(2)催化剂体系的电解性能。对于Pt/C||Zn/NiBP组成的电解池体系,在1和6 mol·L^(−1)KOH中,当电解电流密度达到2000 mA·cm^(−2)时,电解电压分别仅为2.50和2.30 V,表明该催化剂在实际的工业条件下具有优异的电解水性能。 展开更多
关键词 高电流 锌掺杂 产氢 电催化剂 混合电催化剂
在线阅读 下载PDF
Coal gasification fine slag and nitrogen-containing waste co-hydrothermal preparation of porous materials for CO_(2)adsorption
5
作者 WANG Qingyun LIU Xiaqing +2 位作者 MA Li LÜPeng BAI Yonghui 《燃料化学学报(中英文)》 北大核心 2025年第10期1553-1568,共16页
A new adsorbent was successfully prepared by hydrothermal treatment and chemical activation through coal gasification fine slag(CGFS)and blue algae(BA)as raw materials and used for CO_(2)capture.The CO_(2)chemisorptio... A new adsorbent was successfully prepared by hydrothermal treatment and chemical activation through coal gasification fine slag(CGFS)and blue algae(BA)as raw materials and used for CO_(2)capture.The CO_(2)chemisorption capacity of the adsorbent was further enhanced by taking advantage of the nitrogenous bases contained in the BA.In the hydrothermal process,the addition of BA significantly increased the content of pyrrole nitrogen in the adsorbent.In the activation process,pyrrole nitrogen gradually changed into pyridine nitrogen and graphite nitrogen.Increased BA addition result in a higher specific surface area and microporosity of the adsorbent.The CO_(2)adsorption performance test proved that the CGFS-50%-CA sample has the strongest CO_(2)adsorption capacity at low temperature,up to 15.59 cm^(3)/g,which is mainly through physical adsorption,and the CGFS-10%-CA sample has the strongest CO_(2)adsorption capacity at high temperature,up to 7.31 cm^(3)/g,which is mainly through chemical adsorption.CO_(2)uptake of the CGFS-10%-CA sample was well maintained after 10 cycles,with regeneration efficiencies above 99%.The results indicate that the novel adsorbents with coexistence of physical and chemical adsorption have great potential for CO_(2)adsorption applications. 展开更多
关键词 coal gasification fine slag nitrogen-containing waste hydrothermal porous materials CO_(2)adsorption
在线阅读 下载PDF
WGM Lasing from Toroid-shaped ZnO Microdisk Pivoted on Si
6
作者 ZHU Gangyi YAN Xinyue +6 位作者 YE Peng QIN Feifei WANG Zixuan LI Binghui LU Junfeng WANG Xiaoxuan XU Chunxiang 《发光学报》 北大核心 2025年第1期12-22,共11页
Although it has a significant advantage in gain properties,the lack of selective etching processes hinders ZnO lasing in on-chip applications.Herein,the circular ZnO microdisk pivoted on Si substrate is fabricated thr... Although it has a significant advantage in gain properties,the lack of selective etching processes hinders ZnO lasing in on-chip applications.Herein,the circular ZnO microdisk pivoted on Si substrate is fabricated through depositing ZnO on patterned silicon on an insulator(SOI)substrate.The cavity structure,morphology,and photoluminescence(PL)properties are studied systematically.The cavity shows a well-defined circular structure with oxygen vacancies.Under the synergistic action of surface tension and stress,the ZnO microdisk shows a unique toroid structure with a high sidewall surface finish.The ZnO microcavity(8μm in diameter)shows optically pumped whispering gallery modes(WGMs)lasing in the ultraviolet region with a Q factor exceeding 1300.More interestingly,the quality of the toroid ZnO microdisk cavity is high enough to support the bandgap renormalization(BGR)phenomenon.With the increasing pumping power,the lasing spectra will be modulated.The lasing spectrum undergoes a Burstein-Moss(BM)effect-induced blueshift and an electron-hole plasma(EHP)effect-induced redshift. 展开更多
关键词 ZNO MICRODISK tunable lasing molecular beam epitaxy
在线阅读 下载PDF
Simultaneous influences of nanomaterial and fiber reinforcement on enhancing the mechanical performance of geopolymer stabilized soft clayey soils
7
作者 KHOSRAVI Hassan GOODARZI Amir Reza LAJEVARDI Seyed Hamid 《Journal of Central South University》 2025年第2期597-623,共27页
This study was designed to enhance the soft clayey soil treatment effects using an innovative mechanochemically activated geopolymer(GP)through the optimized inclusion of nano-metakaolin(NM)and polypropylene fiber.The... This study was designed to enhance the soft clayey soil treatment effects using an innovative mechanochemically activated geopolymer(GP)through the optimized inclusion of nano-metakaolin(NM)and polypropylene fiber.The study also investigated the possible improvements in the binding ability of GP stabilization under different curing regimes.To this end,binders including lime alone,LG(slag-based geopolymer),LGNM(nano-modified LG with NM)and LGNMF(LGNM/fiber)mixture were separately added to soft soil samples.The fabricated composites were then subjected to a set of macro and micro level tests.The results indicated that,adding LG binary with a 20%NM replacement can lead to a significant increase(by nearly 21 times)in soil strength and a remarkable decline(about 70%)in the compression index.In fact,NM can play a great role in accelerating the rate of hydration reactions and forming a densely packed fabric,which staggeringly improve the soil hydromechanical attributes.It was also observed that raising the curing temperature will effectively augment the polymerization kinetics,leading to a substantial increase(~2 times)in the soil solidification process.However,the stabilized composites containing NM may reveal a brittle nature under more intense stress.Such a potential drawback seems to be resolved by the integration of fibers within the matrix.LGNM combined with fiber would boost(≥10 times)the energy absorption capacity of the soil,notably enhancing its residual strength.Overall,LGNMF may not only feature a broader range of benefits(inc.economic,technical,environmental)compared to traditional binders but also promote the ductility of the GP materials. 展开更多
关键词 soft clayey soil LIME slag-based geopolymer nano-metakaolin(NM) fiber enhanced nanomodification
在线阅读 下载PDF
Study on the characteristics of crack initiation in deep dense shale containing circular hole under varying stress conditions
8
作者 XIE Hong-qiang FENG Gan +4 位作者 LIU Huai-zhong HE Qiang XIAO Ming-li PEI Jian-liang TAHERDANGKOO Reza 《Journal of Central South University》 2025年第1期244-261,共18页
The evolution of cracks in shale directly affects the efficient production of shale gas.However,there is a lack of research on the characteristics of crack initiation in deep dense shale under different stress conditi... The evolution of cracks in shale directly affects the efficient production of shale gas.However,there is a lack of research on the characteristics of crack initiation in deep dense shale under different stress conditions.In this work,considering the different combinations of confining pressure and bedding plane inclination angle(α),biaxial mechanical loading experiments were conducted on shale containing circular holes.The research results indicate that the confining pressure and inclination angle of the bedding planes significantly influence the failure patterns of shale containing circular holes.The instability of shale containing circular holes can be classified into five types:tensile failure along the bedding planes,tensile failure through the bedding planes,shear slip along the bedding planes,shear failure through the bedding planes,and block instability failure.Furthermore,the evolution of strain and stress fields around the circular holes was found to be the fundamental cause of variations in the initiation characteristics and locations of shale cracks.The crack initiation criterion for shale containing circular hole was established,providing a new method for evaluating the trajectory of shale hole wall fractures.This study holds significant importance for evaluating the evolution and stability of fracture networks within shale reservoirs. 展开更多
关键词 shale gas deep dense shale crack initiate characteristics failure modes
在线阅读 下载PDF
Linear WDE for performance enhancement of MIMO-OFDM system in the presence of Co-CFO
9
作者 Khaled Ramadan Emad S.Hassan 《Defence Technology(防务技术)》 2025年第9期51-66,共16页
The Discrete Walsh Hadamard Transform(DWHT)has emerged as an efficient alternative to the Discrete Fourier Transform(DFT)for Orthogonal Frequency Division Multiplexing(OFDM)implementations,particularly in handling cha... The Discrete Walsh Hadamard Transform(DWHT)has emerged as an efficient alternative to the Discrete Fourier Transform(DFT)for Orthogonal Frequency Division Multiplexing(OFDM)implementations,particularly in handling channel impairments.In this article,we proposed an efficient Joint Low Complexity Regularized Zero Forcing-Wavelet Domain Equalizer(JLCRLZF-WDE)to replace the traditional Frequency Domain Equalizer(FDE)in DWHT-OFDM systems.Unlike FDE,which requires additional DFT and Inverse DFT(IDFT)computations,the proposed JLCRLZF-WDE directly operates in the Walsh domain,effectively mitigating the computational overhead.The derivation of the proposed JLCRLZF-WDE equations take the effect of the channel,Co-Carrier Frequency Offset(Co-CFO),as well as the noise into account.During the derivation of the system model equations,we assume a MultipleInput-Multiple-Output(MIMO)-OFDM communication system through a Rayleigh fading channel.The Bit Error Rate(BER)performance and computational complexity of the proposed and the conventional algorithms are compared,indicating the significance of the proposed algorithm.Simulation results confirm the superiority of the proposed equalizer,demonstrating a 23.68%±28.4%reduction in computational complexity compared to Minimum Mean Square Error(LMMSE)-FDE based on DFT,while maintaining comparable BER performance at various MIMO configuration.Furthermore,at a BER of 10^(-4),the JLCRLZF-WDE achieves performance parity with conventional Walsh domain LMMSE equalizers,whereas other equalizers require an additional Signal-to-Noise Ratio(SNR)of 3.06 d B to achieve the same performance. 展开更多
关键词 DWHT WDE FDE OFDM Co-CFO
在线阅读 下载PDF
A general viscoelastic foundation model for vibration analysis of functionally graded sandwich plate with auxetic core
10
作者 Mofareh Hassan Ghazwani Ali Alnujaie Pham Van Vinh 《Defence Technology(防务技术)》 2025年第4期40-58,共19页
This study presents a significant advancement in the vibration analysis of functionally graded sandwich plates with auxetic cores by introducing a general viscoelastic foundation model that more accurately reflects th... This study presents a significant advancement in the vibration analysis of functionally graded sandwich plates with auxetic cores by introducing a general viscoelastic foundation model that more accurately reflects the complex interactions between the plate and the foundation.The novelty of this study is that the proposed viscoelastic foundation model incorporates elastic and damping effects in both the Winkler and Pasternak layers.To develop the theoretical framework for this analysis,the higher-order shear deformation theory is employed,while Hamilton's principle is used to derive the governing equations of motion.The closed-form solution is used to determine the damped vibration behaviors of the sandwich plates.The precision and robustness of the proposed mathematical model are validated through several comparison studies with existing numerical results.A detailed parametric study is conducted to investigate the influence of various parameters,including the elastic and damping coefficients of the foundation,the material gradation,and the properties of the auxetic core on the vibration behavior of the plates.The numerical results provide new insights into the vibration characteristics of sandwich plates with auxetic cores resting on viscoelastic foundation,highlighting the significant role of the two damping coefficients and auxetic cores in the visco-vibration behavior of the plates. 展开更多
关键词 Damped vibration Viscoelastic foundation Sandwich plates Auxetic core Honeycomb core Negative Poisson's ratio
在线阅读 下载PDF
Nonlinear asymmetric thermomechanical buckling of shallow nanoscale arches having dissimilar end conditions embracing nonlocality and strain gradient size dependencies
11
作者 Saeid Sahmani Kamila Kotrasova +2 位作者 Mona Zareichian Jian Sun Babak Safaei 《Defence Technology(防务技术)》 2025年第5期67-82,共16页
The undercurrent research survey explores the roles of nonlocality and strain gradient size dependencies in nonlinear asymmetric buckling of shallow nanoscale arches having dissimilar end conditions through a numerica... The undercurrent research survey explores the roles of nonlocality and strain gradient size dependencies in nonlinear asymmetric buckling of shallow nanoscale arches having dissimilar end conditions through a numerical analysis.The arches,made from a functionally graded graphene nanofiller reinforced composite(FG-GNRC),are subjected to discretional radial concentrated loads along with converting of temperature.To account for the size dependencies,the exploration is carried out stemming from the nonlocal strain gradient theory(NSGT)in the sense of a quasi-2D parabolic shear flexible concept of curved beam.The material properties of the contemplated FG-GNRC sandwich are determined using the modified Halpin-Tsai micromechanics model.Subsequently,an extended isogeometric analysis(XIGA)is manipulated comprising insertion plus multiplication of knots to achieve the demanded lower continuity allocated to the integration between flexural and tangential reflexes.It is perceived that the both softening and stiffening concomitants assigned to the salient concentrated radial loads obtained by the developed NSGT-based XIGA diminish from the first upper limit to the second one,and then likewise from the first lower limit to the second one.Although,by becoming the upsurge in temperature higher,these softening and stiffening concomitants get more remarkable. 展开更多
关键词 Nanotechnology Size-dependent mechanical responses Sandwich composites Extended isogeometric analysis Curved beams
在线阅读 下载PDF
基于数据库的电力设备故障诊断模糊专家系统的设计与实现 被引量:8
12
作者 刘铭 SHI Xin +1 位作者 时昕 姚燕南 《计算机工程》 CAS CSCD 北大核心 2001年第3期75-77,共3页
采用SQL Anywhere 5.0设计知识库、 PowerBuilder6.5编程实现了电力设备故障诊断模糊专家系统,其知识的表示采用了模糊产生式表示法,引进了模糊匹配与加权模糊逻辑进行模糊推理,实现了一种较为理想的... 采用SQL Anywhere 5.0设计知识库、 PowerBuilder6.5编程实现了电力设备故障诊断模糊专家系统,其知识的表示采用了模糊产生式表示法,引进了模糊匹配与加权模糊逻辑进行模糊推理,实现了一种较为理想的非精确推理. 展开更多
关键词 模糊专家系统 故障诊断 模糊推理 电力设备 数据库
在线阅读 下载PDF
PMU准实时数据对主动配电网抗差估计的影响 被引量:16
13
作者 徐艳春 刘晓明 +1 位作者 李振华 吕密 《电力自动化设备》 EI CSCD 北大核心 2020年第10期15-22,共8页
由于相量测量单元(PMU)因成本问题无法在配电网中大规模配置,且不同设备向主站传输数据时存在客观的通信延迟、带宽限制等因素,因此状态估计器输入端存在不良数据。提出一种基于同步相量量测的主动配电网抗差估计方法,并提出以虚拟PMU... 由于相量测量单元(PMU)因成本问题无法在配电网中大规模配置,且不同设备向主站传输数据时存在客观的通信延迟、带宽限制等因素,因此状态估计器输入端存在不良数据。提出一种基于同步相量量测的主动配电网抗差估计方法,并提出以虚拟PMU量测模型补充大量的高精度冗余数据。将数据采集与监视控制(SCADA)量测系统、PMU量测和虚拟PMU量测构成的混合量测系统作为状态估计的输入端。考虑网络和量测数据不确定度对抗差M估计算法进行改进,避免了传统加权最小二乘估计中删除坏数据的残差判断和迭代过程,降低了估计耗时,提高了状态估计的可靠性和抗差性能。改进IEEE 14和IEEE 33节点配电网算例的仿真分析,验证了所提方法的有效性和普适性。 展开更多
关键词 相量测量单元 虚拟PMU量测 改进抗差M估计 量测不确定度 主动配电网
在线阅读 下载PDF
基于模型的构件软件修改影响分析 被引量:11
14
作者 陶传奇 李必信 +1 位作者 Jerry GAO 孙小兵 《软件学报》 EI CSCD 北大核心 2013年第5期942-960,共19页
基于构件的软件构建方法目前被广泛使用在软件开发中,用于减少软件开发的工程成本和加快软件开发进度.面向构件的系统主要由第三方提供的可重用构件或者内建的可重用构件组成,因此,系统的质量好坏和维护的难易程度依赖于构件的品质.一... 基于构件的软件构建方法目前被广泛使用在软件开发中,用于减少软件开发的工程成本和加快软件开发进度.面向构件的系统主要由第三方提供的可重用构件或者内建的可重用构件组成,因此,系统的质量好坏和维护的难易程度依赖于构件的品质.一个软件修改会给其他构件甚至整个系统带来影响,而修改影响分析是控制和消除这类影响的有效手段.然而,现有的研究很少涉及构件软件的修改影响分析,尤其缺少对系统层面的修改影响分析研究.提出了一种基于模型的系统化修改影响分析方法,该方法的基本思路是:首先提出构件及系统层面的修改影响分析模型,然后根据分析模型分别从构件和系统两个层面对构件软件修改前后的版本进行修改识别,并且利用"防火墙"方法进行影响分析.理论分析和实验结果表明,该方法是可行的,也是有效的. 展开更多
关键词 修改影响分析 修改影响分析模型 基于构件的软件 软件维护
在线阅读 下载PDF
N2气氛下煅烧的黄铁矿对As(Ⅲ)的吸附作用 被引量:3
15
作者 史亚丹 陈天虎 +2 位作者 李平 杨燕 彭书传 《岩石矿物学杂志》 CAS CSCD 北大核心 2016年第2期363-370,共8页
微量As(Ⅲ)是水中较难去除的毒性物质,天然黄铁矿对水中As(Ⅲ)的去除能力低于磁黄铁矿.将黄铁矿在氮气下高温煅烧使其转变为由磁黄铁矿构成的多孔结构化材料,具有较高的比表面积和表面化学反应活性,在地下水As(Ⅲ)去除方面具有潜... 微量As(Ⅲ)是水中较难去除的毒性物质,天然黄铁矿对水中As(Ⅲ)的去除能力低于磁黄铁矿.将黄铁矿在氮气下高温煅烧使其转变为由磁黄铁矿构成的多孔结构化材料,具有较高的比表面积和表面化学反应活性,在地下水As(Ⅲ)去除方面具有潜在的应用前景.考察了煅烧温度、煅烧时间、pH值以及溶解氧对去除水中As(Ⅲ)的影响.结果表明黄铁矿煅烧生成的单斜磁黄铁矿对As(Ⅲ)具有最佳去除效果,最佳煅烧条件为600℃煅烧1 h;在水溶液有溶解氧条件下煅烧黄铁矿去除As(Ⅲ)的适宜p H值范围较宽(4~10),而在水溶液缺少溶解氧条件下适宜pH值则变为7~10;煅烧黄铁矿在有氧水溶液中对As(Ⅲ)的吸附比缺氧水溶液中的吸附效果好. 展开更多
关键词 煅烧黄铁矿 As(Ⅲ) 除砷
在线阅读 下载PDF
苹果擦伤拉曼光谱无损检测虚拟系统研究 被引量:15
16
作者 高晓阳 Paul Heinemann Joseph Irudayaraj 《农业工程学报》 EI CAS CSCD 北大核心 2005年第3期130-133,共4页
为检测苹果品质并依据擦伤进行分级,研发了一个基于拉曼光谱的实时无损自动检测分类虚拟仪器分级系统样机。采用一台Nicolet傅氏变换拉曼光谱仪进行苹果擦伤光谱检测。测试集和训练集的苹果光谱用WinDAS的典型变量分析(CVA)和主成分分析... 为检测苹果品质并依据擦伤进行分级,研发了一个基于拉曼光谱的实时无损自动检测分类虚拟仪器分级系统样机。采用一台Nicolet傅氏变换拉曼光谱仪进行苹果擦伤光谱检测。测试集和训练集的苹果光谱用WinDAS的典型变量分析(CVA)和主成分分析法(PCA)进行分类处理。分析得出的模型经UNEQ分类检验,'马氏平方图'和χ2检验结果该分类模型。其次,应用LabVIEW设计苹果虚拟仪器分级控制系统,并制作了样机。试验结果表明拉曼光谱分析能用于苹果擦伤无损检测和类别确定;虚拟仪器分级系统能对苹果进行准确分级处理。 展开更多
关键词 苹果 拉曼光谱 擦伤检测 典型变量分析 不等离中趋势分类 虚拟仪器
在线阅读 下载PDF
自清洗网式过滤器排污系统数值模拟及结构优化 被引量:6
17
作者 吴玉秀 刘贞姬 +2 位作者 谢炎 Seyed Farshid Chini 刘冬冬 《中国农村水利水电》 北大核心 2023年第1期128-133,共6页
自清洗网式过滤器是一种新型过滤器,为提高其排污系统的排污效率,建立了自清洗网式过滤器排污系统旋喷动力和吸附吸力理论表达式,确定旋喷动力和吸附吸力影响因素;利用CFD方法对自清洗网式过滤器排污过程进行数值模拟,分别得到速度云图... 自清洗网式过滤器是一种新型过滤器,为提高其排污系统的排污效率,建立了自清洗网式过滤器排污系统旋喷动力和吸附吸力理论表达式,确定旋喷动力和吸附吸力影响因素;利用CFD方法对自清洗网式过滤器排污过程进行数值模拟,分别得到速度云图和压强云图,结果表明,排污系统吸嘴1~4最大流速差为2.96 m/s,最大压强差为3.65 kPa,排污系统泥沙吸附不均匀,降低了过滤器排污效率;结合理论分析和数值模拟结果设计6组优化方案,对比可知吸沙组件吸嘴1~4开口宽度分别为0.2、0.4、0.6、2 cm,旋喷管开口直径为2 cm的方案,各吸嘴流速分布更加均匀,流速得到明显提高,过滤器进出口压强差增大,有利于提高排污效率。 展开更多
关键词 排污系统 理论分析 数值模拟 结构优化 流速 压强
在线阅读 下载PDF
氮气气氛下黄铁矿热分解的矿物相变研究 被引量:14
18
作者 史亚丹 陈天虎 +2 位作者 李平 朱晓 杨燕 《高校地质学报》 CAS CSCD 北大核心 2015年第4期577-583,共7页
通过差热-热重分析、X射线粉末衍射(XRD)及磁化率分析等手段,对天然黄铁矿样品在氮气中受热发生的矿物相变过程进行了综合研究。不同温度下黄铁矿煅烧产物的XRD物相分析结果显示,低于500℃时,黄铁矿无显著变化;随着温度的升高(500~600... 通过差热-热重分析、X射线粉末衍射(XRD)及磁化率分析等手段,对天然黄铁矿样品在氮气中受热发生的矿物相变过程进行了综合研究。不同温度下黄铁矿煅烧产物的XRD物相分析结果显示,低于500℃时,黄铁矿无显著变化;随着温度的升高(500~600℃),黄铁矿开始转变为单斜磁黄铁矿,进而生成六方磁黄铁矿,磁化率显著升高;700℃~800℃的煅烧产物主要为六方磁黄铁矿,磁化率明显下降,直至900℃进一步形成更稳定的陨硫铁(Fe S),磁化率接近于零。在黄铁矿物相开始转变的温度(500~600℃)区间,黄铁矿生成单斜磁黄铁矿的速率大于单斜磁黄铁矿转化为六方磁黄铁矿的速率;高温(700~900℃)时,黄铁矿转化为单斜磁黄铁矿的速率低于单斜磁黄铁矿转化为六方磁黄铁矿的速率,表现为黄铁矿直接生成六方磁黄铁矿。 展开更多
关键词 黄铁矿 相变 单斜磁黄铁矿 六方磁黄铁矿 磁化率
在线阅读 下载PDF
地道桥竖向自振频率研究 被引量:2
19
作者 周智辉 Wen Yu-song 《铁道学报》 EI CAS CSCD 北大核心 2001年第2期116-119,共4页
结合现场实测资料,提出了地道桥动力特性分析的有限元模型。运用有限元计算模型。计算了各种类型地道桥的竖向基频,并提出正常状态地道桥竖向基频的经验表达式,为估算正常状态地道桥基频提供一种参考方法。
关键词 地道桥 基频 有限元法 竖向自振频率 动力特性分析 计算模型
在线阅读 下载PDF
用V(z)曲线分析压电陶瓷表面的声学特性
20
作者 章德 吴文虬 M.G.Somekh 《应用声学》 CSCD 1990年第4期5-9,共5页
本文利用超声显微镜技术中的V(z)曲线,无损伤地测量了压电陶瓷表面上不同点声表面波(瑞利波)速度,定量地分析了陶瓷的一致性。同时又根据V(z)曲线中周期的起伏,定性地给出了表面颗粒均匀性及缺陷存在的可能性。文中给出了几种不同陶瓷... 本文利用超声显微镜技术中的V(z)曲线,无损伤地测量了压电陶瓷表面上不同点声表面波(瑞利波)速度,定量地分析了陶瓷的一致性。同时又根据V(z)曲线中周期的起伏,定性地给出了表面颗粒均匀性及缺陷存在的可能性。文中给出了几种不同陶瓷材料的实验数据及分析结果,并简单地描述了V(z)曲线的理论与声表面波(瑞利波)速度的计算公式、测试方法。 展开更多
关键词 压电陶瓷 V(Z)曲线 测试 声学特性
在线阅读 下载PDF
上一页 1 2 17 下一页 到第
使用帮助 返回顶部