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Macroscopic environmental heterogeneity and corrosion behavior derived from in vitro degradation of pure magnesium and their in vivo investigation
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作者 Lulu Zhang Kotaro Hanada Kazuhiro Kumagai 《Journal of Magnesium and Alloys》 2025年第7期3186-3197,共12页
Magnesium(Mg)alloys have attracted considerable attention as promising implant materials for biodegradable medical devices.In this study,we focused on investigating the effect of macroscopic environmental heterogeneit... Magnesium(Mg)alloys have attracted considerable attention as promising implant materials for biodegradable medical devices.In this study,we focused on investigating the effect of macroscopic environmental heterogeneity due to the degradation of Mg on its corrosion behavior.The immersion experiments using pure Mg plates,which were placed vertically in a culture medium(Dulbecco’s Modified Eagle’s Medium(DEME)+10%fetal bovine serum(FBS))for 1,5,and 10 days,were conducted.Surface analyses for the corrosion product layers and the measurements of the pH values and concentrations of eluted ions in the immersion medium around the upper and lower areas of the Mg plate were performed.The significant effect of the macroscopic environmental heterogeneity derived from Mg degradation on the corrosion behavior was demonstrated by in vitro tests.Additionally,the in vivo tests were carried out by implanting the pure Mg plates in the femur of rabbits.The in vivo results exhibited macroscopically heterogeneous Mg degradation,with areas of more severe corrosion compared to the in vitro test;it is especially noticeable during the early stage of degradation,even though the average corrosion rate was lower. 展开更多
关键词 Biodegradable Mg Corrosion behavior In vitro In vivo Environmental heterogeneity Corrosion product X-ray photoelectron spectroscopy MICRO-CT
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富血小板血浆联合射频微针治疗高原地区面部光老化的临床效果
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作者 廖程琦 张敏 郑波 《临床医学研究与实践》 2025年第28期105-108,共4页
目的观察富血小板血浆(PRP)联合射频微针治疗高原地区面部光老化的临床效果。方法选取2023年10月至2024年12月在拉萨爱思特医疗美容医院接受治疗的40例高原地区面部光老化患者,按治疗方式将其分为对照组和治疗组,每组20例。对照组采用... 目的观察富血小板血浆(PRP)联合射频微针治疗高原地区面部光老化的临床效果。方法选取2023年10月至2024年12月在拉萨爱思特医疗美容医院接受治疗的40例高原地区面部光老化患者,按治疗方式将其分为对照组和治疗组,每组20例。对照组采用射频微针治疗,治疗组采用PRP联合射频微针治疗。采集治疗前及治疗后6周的面部光谱图像,以光老化整体评分、整体美学改善量表(GAIS)来评估患者治疗前后皮肤质地、细纹、色素等综合改善情况,并记录患者满意度和不良反应。结果治疗前,两组的光老化整体评分比较,差异无统计学意义(P>0.05);治疗后,两组的光老化整体评分均低于治疗前,差异具有统计学意义(P<0.05);治疗后,治疗组的光老化整体评分低于对照组,差异具有统计学意义(P<0.05)。治疗组的可观改善率明显高于对照组,差异具有统计学意义(P<0.05)。治疗组的满意度为80.00%,对照组的满意度为60.00%。观察到的术后不良反应有红斑、肿胀、紫癜、瘀青,均在数日内自行消退。结论PRP联合射频微针治疗高原地区面部光老化安全有效。 展开更多
关键词 射频微针 富血小板血浆 高原地区 面部光老化
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注射型富血小板纤维蛋白联合超完美脉冲光治疗西藏高原地区敏感性皮肤的效果
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作者 郑波 张敏 +4 位作者 魏国祥 廖程琦 李梦琴 邓雍 李林 《临床医学研究与实践》 2025年第34期110-113,共4页
目的观察注射型富血小板纤维蛋白(i-PRF)联合超完美脉冲光(AOPT)治疗西藏高原地区敏感性皮肤的有效性及安全性。方法选取西藏高原地区敏感性皮肤患者50例,根据治疗方案差异将其分为对照组和观察组,每组25例。对照组采用单纯AOPT治疗,观... 目的观察注射型富血小板纤维蛋白(i-PRF)联合超完美脉冲光(AOPT)治疗西藏高原地区敏感性皮肤的有效性及安全性。方法选取西藏高原地区敏感性皮肤患者50例,根据治疗方案差异将其分为对照组和观察组,每组25例。对照组采用单纯AOPT治疗,观察组采用AOPT治疗后行i-PRF真皮内注射。每间隔4周治疗1次,共3次。治疗结束后对比两组患者的临床效果。结果治疗后,两组的主观症状、客观症状评分均明显降低,且观察组低于对照组(P<0.05)。观察组的治疗总有效率为96.00%,高于对照组的72.00%(P<0.05)。结论i-PRF联合AOPT能改善西藏高原地区敏感性皮肤患者的临床症状,修复皮肤屏障功能,提升治疗效果。 展开更多
关键词 注射型富血小板纤维蛋白 超完美脉冲光 敏感性皮肤 皮肤屏障 西藏 高原地区
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Unexpected structural scaling and predictability in carbon nanotubes
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作者 Guohai Chen Kazufumi Kobashi Don N.Futaba 《Journal of Materials Science & Technology》 2025年第28期30-35,共6页
Carbon nanotubes(CNTs)hold immense promise for a wide array of applications due to their exceptional physical and chemical properties.Understanding and controlling their structural characteristics,particu-larly the di... Carbon nanotubes(CNTs)hold immense promise for a wide array of applications due to their exceptional physical and chemical properties.Understanding and controlling their structural characteristics,particu-larly the diameter and number of walls,is crucial for harnessing their full potential.We investigated the relationship between these parameters for both commercially available and lab-scale CNTs,spanning a wide range of outer diameters(1-13 nm)and numbers of walls(1-13).Our findings revealed a com-monality among the structural diversity,rather than a random distribution,as evidenced by a piecewise linear relationship between the outer diameter and number of walls,with an inflection point occurring at approximately 4 nm in diameter.This observation is unexpected,as the CNTs were synthesized using different approaches and growth conditions;yet,as a group,they exhibit a“structural scaling”.Addi-tionally,we made an intriguing observation:despite increases in outer diameter and number of walls,the inner diameters remained relatively constant(4-5 nm)for thicker CNTs with more than three walls.These results suggest that structural properties can be estimated based on diameter,which not only ad-vances our fundamental understanding of CNT synthesis but also provides practical insights for tailoring CNT properties for various applications. 展开更多
关键词 Carbon nanotube Outer diameter Wall number Inner diameter Chemical vapor deposition
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Effects of batch and continuous-flow operation on biotreatment of Mn(II)-containing mine drainage
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作者 Obey Gotore Miho Watanabe +5 位作者 Kunihiro Okano Naoyuki Miyata Taiki Katayama Tetsuo Yasutaka Yuki Semoto Takaya Hamai 《Journal of Environmental Sciences》 2025年第6期401-415,共15页
The biotreatment of mine drainage containing dissolved manganese(Mn)using Mn(II)-oxidizing bacteria is challenging.Sequencing-batch(SBRs)and continuous-flow reactors(CFRs)packed with limestones and inoculated with the... The biotreatment of mine drainage containing dissolved manganese(Mn)using Mn(II)-oxidizing bacteria is challenging.Sequencing-batch(SBRs)and continuous-flow reactors(CFRs)packed with limestones and inoculated with the mine-drainage microbial communitywere compared to determine the removal efficiency of Mn(II)from mine drainage.Mn(II)removal in CFRs was 11.4%±0.0%(mean±standard deviation)in the first two weeks and;it slightly increased to 13.6%±0.0%after four weeks,and more than 94%of Mn(II)was removed under the steady-state treatment phase.The performance of SBRs was more effective,wherein 24.4%±0.1%of Mn was removed in the first two weeks,and in four weeks,surpassed 66.6%±0.2%.Rapid Mn(II)removal observed in the start-up of SBR resulted from higher microbial metabolic activities.The adenosine triphosphate(ATP)content of the microbial community was four-fold more than in CFR,but comparable during the steady-state phase.The Mn-oxide deposits occurring in the SBR and CFR at steady-state were mixed phases of birnessite and woodruffite,and the average Mn oxidation valence in the SBR(+3.73)was slightly higher than that in the CFR(+3.54).During the start-up treatment,the closest relatives of Methyloversatilis,Methylibium,and Curvibacter dominated the SBR,whereas putative Mn oxidizers were associated with Hyphomicrobium,Pedobacter,Pedomicrobium,Terricaulis sp.,Sulfuritalea,and Terrimonas organisms.The growth of potential Mnoxidizing genera,including Mesorhizobium,Rhodococcus,Hydrogenophaga,Terricaulis sp.,and‘Candidatus Manganitrophus-noduliformans’was observed under the steady state.The SBR operation was effective as a prior start-up treatment for mine drainage-containing Mn(II),through which the CFR performed well as posterior bio-treatment. 展开更多
关键词 Start-up bioreactor Woodruffite-like Mn(III/VI)oxides Bacterial communities Mine drainage Manganese oxidation BIOTREATMENT
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Robust Load Frequency Control in Hybrid Power Systems Using QOSCA-Tuned PID with EV Loads
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作者 Pralay Roy Pabitra Kumar Biswas +1 位作者 Chiranjit Sain Taha Selim Ustun 《Energy Engineering》 2025年第10期4035-4060,共26页
This study presents the use of an innovative population-based algorithm called the Sine Cosine Algorithm and its metaheuristic form,Quasi Oppositional Sine Cosine Algorithm,to automatic generation control of a multipl... This study presents the use of an innovative population-based algorithm called the Sine Cosine Algorithm and its metaheuristic form,Quasi Oppositional Sine Cosine Algorithm,to automatic generation control of a multiple-source-based interconnected power system that consists of thermal,gas,and hydro power plants.The Proportional-Integral-Derivative controller,which is utilized for automated generation control in an interconnected hybrid power systemwith aDClink connecting two regions,has been tuned using the proposed optimization technique.An Electric Vehicle is taken into consideration only as an electrical load.The Quasi Oppositional Sine Cosinemethod’s performance and efficacy have been compared to the Sine Cosine Algorithm and optimal output feedback controller tuning performance.Applying the QOSCA optimization technique,which has only been shown in this study in the context of an LFC research thus far,makes this paper unique.The main objective has been used to assess and compare the dynamic performances of the recommended controller along with QOSCA optimisation technic.The resilience of the controller is examined using two different system parameters:B(frequency bias parameter)and R(governor speed regulation).The sensitivity analysis results demonstrate the high reliability of the QOSCA algorithm-based controller.Once optimal controller gains are established for nominal conditions,step load perturbations up to±10%&±25%in the nominal values of the systemparameters and operational load condition do not require adjustment of the controller.Ultimately,a scenario is examined whereby EVs are used for area 1,and a single PID controller is used rather than three. 展开更多
关键词 Automatic generation control multi-source interconnected power system electric vehicle
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Hybrid Forecasting Techniques for Renewable Energy Integration in Electricity Markets Using Fractional and Fractal Approach
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作者 Tariq Ali Muhammad Ayaz +3 位作者 Mohammad Hijji Imran Baig MI Mohamed Ershath Saleh Albelwi 《Computer Modeling in Engineering & Sciences》 2025年第12期3839-3858,共20页
The integration of renewable energy sources into electricity markets presents significant challenges due to the inherent variability and uncertainty of power generation from wind,solar,and other renewables.Accurate fo... The integration of renewable energy sources into electricity markets presents significant challenges due to the inherent variability and uncertainty of power generation from wind,solar,and other renewables.Accurate forecasting is crucial for ensuring grid stability,optimizing market operations,and minimizing economic risks.This paper introduces a hybrid forecasting framework incorporating fractional-order statistical models,fractal-based feature enginering,and deep learning architectures to improve renewable energy forecasting accuracy.Fractional autoregressive integrated moving average(FARIMA)and fractional exponential smoothing(FETS)models are explored for capturing long-memory dependencies in energy time-series data.Additionally,multifractal detrended fluctuation analysis(MFDFA)is used to analyze the intermittency of renewable energy generation.The hybrid approach further integrates wavelet transforms and convolutional long short-term memory(CNN-LSTM)networks to model shortand long-term dependencies effectively.Experimental results demonstrate that fractional and fractal-based hybrid forecasting techniques significantly outperform traditional models in terms of accuracy,reliability,and adaptability to energy market dynamics.This research provides insights for market participants,policymakers,and grid operators to develop more robust forecasting frameworks,ensuring a more sustainable and resilient electricity market. 展开更多
关键词 Hybrid forecasting fractional calculus fractal time-series analysis renewable energy integration electricity markets deep learning statistical models management
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Graph-Embedded Neural Architecture Search: A Variational Approach for Optimized Model Design
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作者 Kazuki Hemmi Yuki Tanigaki +1 位作者 Kaisei Hara Masaki Onishi 《Computers, Materials & Continua》 2025年第8期2245-2271,共27页
Neural architecture search(NAS)optimizes neural network architectures to align with specific data and objectives,thereby enabling the design of high-performance models without specialized expertise.However,a significa... Neural architecture search(NAS)optimizes neural network architectures to align with specific data and objectives,thereby enabling the design of high-performance models without specialized expertise.However,a significant limitation of NAS is that it requires extensive computational resources and time.Consequently,performing a comprehensive architectural search for each new dataset is inefficient.Given the continuous expansion of available datasets,there is an urgent need to predict the optimal architecture for the previously unknown datasets.This study proposes a novel framework that generates architectures tailored to unknown datasets by mapping architectures that have demonstrated effectiveness on the existing dataset into a latent feature space.As NAS is inherently represented as graph structures,we employed an encoder-decoder transformation model based on variational graph auto-encoders to perform this latent feature mapping.The encoder-decoder transformation model demonstrates strong capability in extracting features from graph structures,making it particularly well-suited for mapping NAS architectures.By training variational graph auto-encoders on existing high-quality architectures,the proposed method constructs a latent space and facilitates the design of optimal architectures for diverse datasets.Furthermore,to effectively define similarity amongarchitectures,wepropose constructing the latent spaceby incorporatingbothdataset andtaskfeatures.Experimental results indicate that our approach significantly enhances search efficiency and outperforms conventional methods in terms of model performance. 展开更多
关键词 Neural architecture search automated machine learning artificial intelligence deep learning graph neural network
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Amorphous-to-crystalline transition-induced two-step thin film growth of quasi-one-dimensional penta-telluride ZrTe_(5)
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作者 Yi Shuang Yuta Saito +3 位作者 Shogo Hatayama Paul Fons Ando Daisuke Yuji Sutou 《Journal of Materials Science & Technology》 2025年第7期246-253,共8页
Quasi-one-dimensional(quasi-1D)van der Waals(vdWs)materials,such as ZrTe_(5),exhibit unique elec-trical properties and quantum phenomena,making them attractive for advanced electronic applications.However,large-scale ... Quasi-one-dimensional(quasi-1D)van der Waals(vdWs)materials,such as ZrTe_(5),exhibit unique elec-trical properties and quantum phenomena,making them attractive for advanced electronic applications.However,large-scale growth of ZrTe_(5) thin films presents challenges.We address this by employing sput-tering,a common semiconductor industry technique.The as-deposited ZrTe_(5) film is amorphous,and post-annealing induces a crystallization process akin to transition-metal dichalcogenides.Our study in-vestigates the electrical and optical properties during this amorphous-to-crystalline transition,reveal-ing insights into the underlying mechanism.This work contributes to the fundamental understanding of quasi-1D materials and introduces a scalable fabrication method for ZrTe_(5) which offers the possibility of fabricating unique future electronic and optical devices. 展开更多
关键词 QUASI-ONE-DIMENSIONAL ZrTe_(5) Large-scale Thin film PHASE-CHANGE
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Locally-doped MoS_(2) monolayer with in-plane bifunctional heterostructure toward overall water splitting
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作者 Zhuo-Jun Duan Hang Xia +10 位作者 Han-Ze Li Gong-Lei Shao Yi-Zhang Ren Xuan Tang Qiu-Nan Liu Jin-Hua Hong Sheng Dai Yung-Chang Lin Kazu Suenaga Yong-Min He Song Liu 《Rare Metals》 2025年第5期3130-3140,共11页
Exploring earth-abundant,highly active bifunctional electrocatalysts for efficient hydrogen and oxygen evolution is crucial for water splitting.However,due to their distinct free energies and conducting behaviors(elec... Exploring earth-abundant,highly active bifunctional electrocatalysts for efficient hydrogen and oxygen evolution is crucial for water splitting.However,due to their distinct free energies and conducting behaviors(electron/hole),balancing the catalytic efficiency between hydrogen and oxygen evolution remains challenging for achieving bifunctional electrocatalysts.Here,we report a locally-doped MoS_(2)monolayer with an in-plane heterostructure acting as a bifunctional electrocatalyst and apply it to the overall water splitting.In this heterostructure,the core region contains Mo/S vacancies,while the ring region was doped by Fe atoms(in two substitution configurations:1FeMo and 3FeMo-VS clusters)with a p-type conductive characteristic.Our micro-cell measurements,combined with density functional theory(DFT)calculations,reveal that the vacancies-rich core region presents remarkable hydrogen evolution reaction(HER)activity while the Fe-doped ring gives an excellent oxygen evolution reaction(OER)activity,thus forming an in-plane bifunctional electrocatalyst.Finally,as a proof-of-concept for overall water splitting,we constructed a full-cell configuration based on a locally-doped MoS_(2)monolayer,which achieved a cell voltage of 1.87 V at 10 mA·cm^(-2),demonstrating outstanding performance in strong acid electrolytes.Our work provides insight into the hetero-integration of bifunctional electrocatalysts at the atomic level,paving the way for designing transition metal dichalcogenide catalysts with activity-manipulated regions capable of multiple reactions. 展开更多
关键词 Locally-doped monolayer In-plane heterostructure MoS_(2) Bifunctional catalysts Overall water salitting
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A Hybrid CNN-Transformer Framework for Normal Blood Cell Classification:Towards Automated Hematological Analysis
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作者 Osama M.Alshehri Ahmad Shaf +7 位作者 Muhammad Irfan Mohammed M.Jalal Malik A.Altayar Mohammed H.Abu-Alghayth Humood Al Shmrany Tariq Ali Toufique A.Soomro Ali G.Alkhathami 《Computer Modeling in Engineering & Sciences》 2025年第7期1165-1196,共32页
Background:Accurate classification of normal blood cells is a critical foundation for automated hematological analysis,including the detection of pathological conditions like leukemia.While convolutional neural networ... Background:Accurate classification of normal blood cells is a critical foundation for automated hematological analysis,including the detection of pathological conditions like leukemia.While convolutional neural networks(CNNs)excel in local feature extraction,their ability to capture global contextual relationships in complex cellular morphologies is limited.This study introduces a hybrid CNN-Transformer framework to enhance normal blood cell classification,laying the groundwork for future leukemia diagnostics.Methods:The proposed architecture integrates pre-trained CNNs(ResNet50,EfficientNetB3,InceptionV3,CustomCNN)with Vision Transformer(ViT)layers to combine local and global feature modeling.Four hybrid models were evaluated on the publicly available Blood Cell Images dataset from Kaggle,comprising 17,092 annotated normal blood cell images across eight classes.The models were trained using transfer learning,fine-tuning,and computational optimizations,including cross-model parameter sharing to reduce redundancy by reusing weights across CNN backbones and attention-guided layer pruning to eliminate low-contribution layers based on attention scores,improving efficiency without sacrificing accuracy.Results:The InceptionV3-ViT model achieved a weighted accuracy of 97.66%(accounting for class imbalance by weighting each class’s contribution),a macro F1-score of 0.98,and a ROC-AUC of 0.998.The framework excelled in distinguishing morphologically similar cell types demonstrating robustness and reliable calibration(ECE of 0.019).The framework addresses generalization challenges,including class imbalance and morphological similarities,ensuring robust performance across diverse cell types.Conclusion:The hybrid CNN-Transformer framework significantly improves normal blood cell classification by capturing multi-scale features and long-range dependencies.Its high accuracy,efficiency,and generalization position it as a strong baseline for automated hematological analysis,with potential for extension to leukemia subtype classification through future validation on pathological samples. 展开更多
关键词 Acute leukemia automated diagnosis blood cell classification convolution neural networks deep learning fine-tuning hematologic malignancy hybrid deep learning architecture leukemia subtype classification medical image analysis transfer learning vision transformers
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二维纳米材料MXene的研究进展 被引量:38
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作者 郑伟 孙正明 +3 位作者 张培根 田无边 王英 张亚梅 《材料导报》 EI CAS CSCD 北大核心 2017年第9期1-14,共14页
MXene是一类新型碳/氮化物二维纳米层状材料,一般是利用化学刻蚀的手段通过选择性刻蚀掉前驱体MAX相中的A原子层而得到。其通式可表示为M_(n+1)X_nT_x,其中M代表早期过渡族金属,X代表碳和/或氮,T_x代表MXene在刻蚀过程中产生的附着在其... MXene是一类新型碳/氮化物二维纳米层状材料,一般是利用化学刻蚀的手段通过选择性刻蚀掉前驱体MAX相中的A原子层而得到。其通式可表示为M_(n+1)X_nT_x,其中M代表早期过渡族金属,X代表碳和/或氮,T_x代表MXene在刻蚀过程中产生的附着在其表面的官能团(-OH、-F、=O、等)。采用一定的手段将多层MXene剥落,可获得类石墨烯形貌的单层MXene。MXene除了具备传统二维材料的性能外,还兼具良好的导电性、亲水性、透光性、柔韧性以及能量储存性能,在复合材料、润滑剂、环境污染治理、电池、电容器、催化、传感器、抗菌等领域具有潜在的应用价值。文章总结了MXene的制备、结构、性能和应用等方面的最新成果,并展望了其今后的研究方向。 展开更多
关键词 MAX相 MXene 二维材料 刻蚀 制备 应用
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过渡金属催化磷—氢键的转化反应 被引量:7
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作者 徐清 赵长秋 +2 位作者 周永波 尹双凤 韩立彪 《有机化学》 SCIE CAS CSCD 北大核心 2012年第10期1761-1775,共15页
有机膦化合物在有机合成、催化、生化、医药以及材料等各个领域都起重要的作用.主要总结了本课题组近几年来在过渡金属催化磷—氢化合物的转化反应研究方面取得的进展,包括磷—氢化合物对各种碳—碳不饱和化合物的区域立体选择性加成反... 有机膦化合物在有机合成、催化、生化、医药以及材料等各个领域都起重要的作用.主要总结了本课题组近几年来在过渡金属催化磷—氢化合物的转化反应研究方面取得的进展,包括磷—氢化合物对各种碳—碳不饱和化合物的区域立体选择性加成反应、不对称磷—氢加成反应和磷—氢化合物与碳—氢和杂原子—氢化合物的氧化或脱氢偶联反应.我们开发的反应提供了一系列制备各类不同精细有机膦化合物的相对高效和高原子经济性的新方法,相关反应的机理也将做适当讨论. 展开更多
关键词 过渡金属催化剂 磷-氢化合物 区域立体选择加成反应 碳-碳不饱和化合物 氧化/脱氢偶联反应 碳-氢和杂原子-氢化合物 精细有机膦化合物
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关于2021年5月滇西漾濞M_(S)6.4地震序列特征及成因的初步研究 被引量:57
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作者 雷兴林 王志伟 +1 位作者 马胜利 何昌荣 《地震学报》 CSCD 北大核心 2021年第3期261-286,I0001,共27页
2021年5月21日21时48分在滇西苍山西麓漾濞地区发生M_(S)6.4(MW6.1)强震,相关地震活动表现为一个典型的前震-主震-余震序列。本研究分别就该地震序列的构造背景、M1.0以上地震的双差定位、主要地震的矩张量反演和破裂传播方向、应力场... 2021年5月21日21时48分在滇西苍山西麓漾濞地区发生M_(S)6.4(MW6.1)强震,相关地震活动表现为一个典型的前震-主震-余震序列。本研究分别就该地震序列的构造背景、M1.0以上地震的双差定位、主要地震的矩张量反演和破裂传播方向、应力场反演及断层滑动趋势以及潮汐作用等方面进行了初步分析。矩张量反演结果表明,矩心深度为6.0 km。根据断层破裂传播方向分析结果及精定位余震分布判定,主震震源断层产状为走向137°,倾角75°,滑动角-167°,破裂沿南东向单侧扩展,右旋走滑含正断层分量。漾濞地震序列发生在红河断裂带北段延伸方向上的乔后—巍山断裂附近,但主震震源断层及主要余震的分布在走向和位置上均明显偏离已知的乔后—巍山断裂。地震序列受一个发育程度不高、含多级雁列构造的北西向为主、北东向为次的共轭走滑断层系统(本文称为"漾濞断层")所控制,整体上沿北西向断层展布,主震与部分强余震为北西向断层活动所致,但中强前震和多数余震为北东向断层活动所致。中强震的断层破裂均为单侧扩展,北西向断层主要表现为南东向破裂扩展,而北东向断层沿两个方向破裂扩展,相邻地震还存在往返破裂现象。对截至5月23日所发生的M>4.0前震和余震进行了全矩张量反演。利用漾濞地震震中15 km范围内20多个MW>3.4余震的比较可靠的震源机制解反演了该区的应力场,结果显示:主应力形状比φ=(σ_(2)-σ_(3))/(σ_(1)-σ_(3))为0.46±0.17;最大主应力轴的方位角为188.0°±9.0°,倾伏角为12.4°±7.0°;中间主应力轴近直立,倾伏角为72.1°±11.3°;最小主应力轴的方位角为280.3°±7.0°,倾伏角为10.4°±12.0°。本文还对理论潮汐应变及应力进行了分析,结果表明,该地震序列受潮汐调制作用十分明显。5月18日18时及19日20时开始的两组前震群的首个主要地震以及5月21日晚发生的主震均发生在潮汐体应变和库仑应力的峰值附近,余震活动也与潮汐有明显的相关性。综合主要地震震源机制解、前震及余震分布、潮汐调制特征、基于应力场反演的断层滑动趋势分析以及滇西北地区以往类似地震活动研究结果,本文初步推断:漾濞地震受深部流体作用的影响明显,5月18日18时开始的第一次前震活动高潮从北西向断层的一个拉张性断层阶区开始,最大前震的震源断层为北东向断层,随后向北西方向迁移;19日20时开始的第二次前震活动高潮集中在主震震源附近。这些地震的触发及深部流体作用共同促进了北西向断层的活动,但主震的发生受深部流体作用为主。 展开更多
关键词 矩张量反演 应力场反演 前震 破裂方向性 滑动趋势 地下流体 潮汐调制
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新型NbMoCrTiAl-1Si-xB(x=0、1)难熔高熵合金的微观组织及高温氧化行为研究 被引量:12
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作者 要玉宏 梁霄羽 +3 位作者 金耀华 王正品 刘江南 南條弘 《表面技术》 EI CAS CSCD 北大核心 2020年第6期224-235,共12页
目的进一步改善新型低密度难熔高熵合金NbMoCrTiAl-1Si的高温氧化能力。方法采用非自耗真空电弧熔炼技术配合水冷铜模制备了NbMoCrTiAl-1Si-xB(x=0、1)合金,于1173 K下,在TGA/DSC1型热重及同步热分析仪上进行了48 h高温氧化试验,通过XRD... 目的进一步改善新型低密度难熔高熵合金NbMoCrTiAl-1Si的高温氧化能力。方法采用非自耗真空电弧熔炼技术配合水冷铜模制备了NbMoCrTiAl-1Si-xB(x=0、1)合金,于1173 K下,在TGA/DSC1型热重及同步热分析仪上进行了48 h高温氧化试验,通过XRD、SEM及EDS分析了该合金的组织结构和高温氧化机制。结果铸态NbMoCrTiAl-1Si-xB(x=0、1)合金具有典型的枝晶状组织,1%B元素的添加不会改变合金枝晶的组织结构,但会使枝晶间组织形态由黑色纳米颗粒状转变为亮白色短棒状。NbMoCrTiAl-1Si合金的氧化过程由初期线性快速氧化阶段和后期抛物线慢速氧化阶段组成,氧化总增重为1.064 mg/cm^2,而NbMoCrTiAl-1Si-1B合金氧化过程则可分为具有两个不同氧化速率常数的抛物线氧化阶段,氧化总增重约为NbMoCrTiAl-1Si合金氧化总增重的1/2。经48 h高温氧化后,NbMoCrTiAl-1Si合金表面氧化膜凹凸不平,枝晶间发生了明显的内氧化现象,形成了枝晶内以片状和针状刚玉结构的Al2O3为主,枝晶间以团簇状金红石结构的TiO2为主的氧化膜,NbMoCrTiAl-1Si-1B合金表面氧化膜相对平坦,整个试样表面覆盖了一层由Al2O3、TiO2和Ti0.4Al0.3Nb0.3O2等组成的连续、致密的氧化膜。结论1%B元素的添加会促进NbMoCrTiAl-1Si-1B合金表面Al2O3和TiO2等致密氧化物的形成,抑制合金内氧化进程,显著提高合金抗高温氧化能力。 展开更多
关键词 新型难熔高熵合金 NbMoCrTiAl-1Si 电弧熔炼 组织结构 抗氧化性 氧化膜 金红石结构 刚玉结构
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Mo基分子筛催化剂及甲烷无氧芳构化 被引量:12
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作者 胥月兵 陆江银 +1 位作者 王吉德 张战国 《化学进展》 SCIE CAS CSCD 北大核心 2011年第1期90-106,共17页
本文综述了甲烷无氧芳构化反应及Mo基分子筛催化剂的研究进展。在众多的催化剂中以Mo基分子筛催化性能最佳。概括了催化剂中关于MoOx前躯体结构和其在分子筛中落位,Mo2C物种和诱导期等;讨论了反应中涉及的中间产物、双功能机理以及催化... 本文综述了甲烷无氧芳构化反应及Mo基分子筛催化剂的研究进展。在众多的催化剂中以Mo基分子筛催化性能最佳。概括了催化剂中关于MoOx前躯体结构和其在分子筛中落位,Mo2C物种和诱导期等;讨论了反应中涉及的中间产物、双功能机理以及催化剂失活等问题;归纳了催化剂制备过程中制备方法、焙烧温度与时间、Mo载量和分子筛硅铝比以及催化剂预处理对反应活性的影响;综述了提高催化剂催化性能和反应性能的各种方法,并对其分析,同时介绍了两种催化剂再生方法。最后,依据本实验室研究进展,对甲烷芳构化从工艺角度进行一些可行性讨论,并提出相关问题和展望。 展开更多
关键词 甲烷 无氧芳构化 芳烃 Mo基催化剂
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鄂尔多斯块体周缘地区近期地震活动性与汶川地震应力触发作用的关系 被引量:12
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作者 朱艾斓 解朝娣 +3 位作者 徐锡伟 周永胜 Lei Xinglin 王亚丽 《地学前缘》 EI CAS CSCD 北大核心 2010年第5期206-214,共9页
采用β统计对汶川地震前后鄂尔多斯块体周缘地区的地震活动率进行了空间扫描分析,并采用JiChen的震源破裂模型计算了汶川地震产生的库仑破裂应力变化,以研究鄂尔多斯块体周缘地区近期地震活动性与汶川地震应力触发作用的关系。结果发现... 采用β统计对汶川地震前后鄂尔多斯块体周缘地区的地震活动率进行了空间扫描分析,并采用JiChen的震源破裂模型计算了汶川地震产生的库仑破裂应力变化,以研究鄂尔多斯块体周缘地区近期地震活动性与汶川地震应力触发作用的关系。结果发现,鄂尔多斯块体西南缘弧形断裂束的南东段与南缘渭河盆地的地震活动率在汶川地震后提高显著,其他区域的地震活动率没有明显提高,库仑破裂应力计算得到两个区域的应力变化范围分别为0.005~0.02 MPa和0.001~0.01 MPa,表明汶川地震有可能触发了这两个区域的地震活动。鄂尔多斯块体东缘的山西断陷带处于库仑破裂应力计算的应力增加区,应力变化范围为0~0.012 MPa,2009年3月以来发生的4次ML4.5~5.2级强有感至微破坏地震有可能被汶川地震所延迟触发。b值、地震能量释放率与空间相关距离SCL等地震活动性参数随时间变化扫描结果显示,该区域可能处于不断趋近高应力累积的状态,其未来大震有可能提前发生。西缘地区为应力减小区,其目前的地震活动处于正常水平状态。 展开更多
关键词 地震活动性 β统计 汶川地震 应力触发 鄂尔多斯周缘地区
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Carbon fluxes and their response to environmental variables in a Dahurian larch forest ecosystem in northeast China 被引量:7
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作者 王辉民 三枝信子 +3 位作者 祖元刚 王文杰 山本晋 近藤裕昭 《Journal of Forestry Research》 SCIE CAS CSCD 2008年第1期1-10,共10页
The Dahurian larch forest in northeast China is important due to its vastness and location within a transitional zone from boreal to temperate and at the southern distribution edge of the vast Siberian larch forest. T... The Dahurian larch forest in northeast China is important due to its vastness and location within a transitional zone from boreal to temperate and at the southern distribution edge of the vast Siberian larch forest. The continuous carbon fluxes were measured from May 2004 to April 2005 in the Dahurian larch forest in Northeast China using an eddy covariance method. The results showed that the ecosystem released carbon in the dormant season from mid-October 2004 to April 2005, while it assimilated CO2 from the atmosphere in the growing season from May to September 2004. The net carbon sequestration reached its peak of 112 g.m^-2.month ^-1 in June 2004 (simplified expression of g (carbon).m^-2.month^-1) and then gradually decreased. Annually, the larch forest was a carbon sink that sequestered carbon of 146 g-m^-2.a^-1 (simplified expression of g (carbon).m^-2.a^-1) during the measurements. The photosynthetic process of the larch forest ecosystem was largely affected by the vapor pressure deficit (VPD) and temperature. Under humid conditions (VPD 〈 1.0 kPa), the gross ecosystem production (GEP) increased with increasing temperature. But the net ecosystem production (NEP) showed almost no change with increasing temperature because the increment of GEP was counterbalanced by that of the ecosystem respiration. Under a dry environment (VPD 〉 1.0 kPa), the GEP decreased with the increasing VPD at a rate of 3.0 μmol.m^-2.s^-1kPa -1 and the ecosystem respiration was also enhanced simultaneously due to the increase of air temperature, which was linearly correlated with the VPD. As a result, the net ecosystem carbon sequestration rapidly decreased with the increasing VPD at a rate of 5.2 μmol.m^-2.s-1.kPa^-1. Under humid conditions (VPD 〈 1.0 kPa), both the GEP and NEP were obviously restricted by the low air temperature but were insensitive to the high temperature because the observed high temperature value comes within the category of the optimum range. 展开更多
关键词 carbon balance eddy covariance method environmental effect larch forest Larix gmelinii
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南黄海中部泥质区YE-2孔8.4kaBP来的沉积特征 被引量:29
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作者 王利波 杨作升 +4 位作者 赵晓辉 邢磊 赵美训 Yoshiki Saito 范德江 《海洋地质与第四纪地质》 CAS CSCD 北大核心 2009年第5期1-11,共11页
对取自南黄海中部泥质区YE-2钻孔的6.1m岩心进行了年代学、沉积学、微体古生物学和U3K7′海表温度分析,结果显示,该孔沉积物基本类型为黏土质粉砂,8400aBP来的沉积环境可分为3段:8.4~6.9kaBP为砂含量达13%的滨岸浅水环境;6.9~6.1kaBP... 对取自南黄海中部泥质区YE-2钻孔的6.1m岩心进行了年代学、沉积学、微体古生物学和U3K7′海表温度分析,结果显示,该孔沉积物基本类型为黏土质粉砂,8400aBP来的沉积环境可分为3段:8.4~6.9kaBP为砂含量达13%的滨岸浅水环境;6.9~6.1kaBP为砂含量8%的滨岸浅水向稳定浅海过渡的环境;6.1~0kaBP为基本不含砂的黏土质粉砂稳定浅海环境。表层海水温度(SST)在滨岸浅水阶段较低,平均约14.2℃;在第2阶段从6.9kaBP开始增加,最高达18.1℃,指示了黄海暖流的入侵;6.4kaBP增温结束后,浅海阶段SST稳定在15~16℃之间,同时有3个SST平均为13.9℃的短暂低温期,大致为5.7~5.2、3.7~3.2和2.3~1.8kaBP。在稳定浅海环境的黏土质粉砂地层中发现了罕见的3个砂质粉砂质粗粒级夹层,大致形成于6.0、3.9和2.5kaBP,其粒度具有风暴沉积特征,重矿物表现出变质岩特点,U3K7′-SST和黏土矿物指示其沉积环境的温度偏高。上述特征与岩心其他所有层位差异较大,显示了异地搬运的特征,可能为风暴沉积。根据AMS14C测年,不考虑风暴沉积,YE-2岩心的沉积速率在50.7~75.6cm/ka之间。 展开更多
关键词 泥质沉积 古环境 U37K′-SST 粗粒级夹层 南黄海
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硼对AlMo0.5NbTa0.5TiZr难熔高熵合金组织和高温氧化性能的影响 被引量:10
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作者 要玉宏 梁霄羽 +2 位作者 金耀华 王正品 南條弘 《表面技术》 EI CAS CSCD 北大核心 2020年第2期235-242,287,共9页
目的提高AlMo0.5NbTa0.5TiZr难熔高熵合金的抗氧化性能。方法采用非自耗真空电弧熔炼法制备了AlMo0.5NbTa0.5TiZrBx(x=0、0.02、0.06)难熔高熵合金,通过系列高温氧化试验、X射线衍射分析和扫描电镜及能谱分析,研究了微量B元素的添加对... 目的提高AlMo0.5NbTa0.5TiZr难熔高熵合金的抗氧化性能。方法采用非自耗真空电弧熔炼法制备了AlMo0.5NbTa0.5TiZrBx(x=0、0.02、0.06)难熔高熵合金,通过系列高温氧化试验、X射线衍射分析和扫描电镜及能谱分析,研究了微量B元素的添加对该合金组织结构和高温氧化性能的影响规律。结果铸态AlMo0.5NbTa0.5TiZr合金具有典型的枝晶状凝固组织,包括由黑色枝晶间区的富Al-Ti-Zr的BCC1相、明亮枝晶区的富Mo-Nb-Ta的BCC2相以及枝晶边缘灰色过渡区的富Al-Zr相。微量B的添加没有改变AlMo0.5NbTa0.5TiZr相组成,但使合金的枝晶组织明显细化。添加B以后,AlMo0.5NbTa0.5TiZrBx合金的放热峰强度由0.95 W/g降至0.05 W/g,氧化反应的峰值温度由880℃升至1020℃;添加适量的B可改善合金短时氧化过程中的氧化皮剥落现象,并可防止合金在长时氧化过程中出现灾难性氧化。由于B的添加,AlMo0.5NbTa0.5TiZrB0.06合金表面在800℃氧化50 h过程中形成了Nb4Ta2O15和AlNbO4等具有保护性的复杂氧化物。结论添加适量的B元素不仅可抑制AlMo0.5NbTa0.5TiZr合金在800~1200℃之间的氧化反应和氧化增重程度,而且可以大幅提高合金在800℃+3 h和800℃+50 h条件下的氧化抗力。 展开更多
关键词 难熔高熵合金 组织结构 抗氧化性 氧化膜 Nb4Ta2O15 AlNbO4
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