期刊文献+
共找到43篇文章
< 1 2 3 >
每页显示 20 50 100
A process-oriented approach for identifying potential landslides considering time-dependent behaviors beyond geomorphological features
1
作者 xiang sun Guoqing Chen +4 位作者 Xing Yang Zhengxuan Xu Jingxi Yang Zhiheng Lin Yunpeng Liu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第3期961-978,共18页
Geomorphological features are commonly used to identify potential landslides.Nevertheless,overemphasis on these features could lead to misjudgment.This research proposes a process-oriented approach for potential lands... Geomorphological features are commonly used to identify potential landslides.Nevertheless,overemphasis on these features could lead to misjudgment.This research proposes a process-oriented approach for potential landslide identification that considers time-dependent behaviors.The method integrates comprehensive remote sensing and geological analysis to qualitatively assess slope stability,and employs numerical analysis to quantitatively calculate aging stability.Specifically,a time-dependent stability calculation method for anticlinal slopes is developed and implemented in discrete element software,incorporating time-dependent mechanical and strength reduction calculations.By considering the time-dependent evolution of slopes,this method highlights the importance of both geomorphological features and time-dependent behaviors in landslide identification.This method has been applied to the Jiarishan slope(JRS)on the Qinghai-Tibet Plateau as a case study.The results show that the JRS,despite having landslide geomorphology,is a stable slope,highlighting the risk of misjudgment when relying solely on geomorphological features.This work provides insights into the geomorphological characterization and evolution history of the JRS and offers valuable guidance for studying slopes with similar landslide geomorphology.Furthermore,the process-oriented method incorporating timedependent evolution provides a means to evaluate potential landslides,reducing misjudgment due to excessive reliance on geomorphological features. 展开更多
关键词 Geomorphological features Evolution history Time-dependent stability calculation Landslides identification Qinghai-Tibet Plateau
下载PDF
Numerical study on gas production via a horizontal well from hydrate reservoirs with different slope angles in the South China Sea
2
作者 Tingting Luo Jianlin Song +5 位作者 xiang sun Fanbao Cheng Madhusudhan Bangalore Narasimha Murthy Yulu Chen Yi Zhao Yongchen Song 《Deep Underground Science and Engineering》 2024年第2期171-181,共11页
It is important to study the effect of hydrate production on the physical and mechanical properties of low-permeability clayey–silty reservoirs for the largescale exploitation of hydrate reservoirs in the South China... It is important to study the effect of hydrate production on the physical and mechanical properties of low-permeability clayey–silty reservoirs for the largescale exploitation of hydrate reservoirs in the South China Sea.In this study,a multiphysical-field coupling model,combined with actual exploration drilling data and the mechanical experimental data of hydrate cores in the laboratory,was established to investigate the physical and mechanical properties of low-permeability reservoirs with different slope angles during 5-year hydrate production by the depressurization method via a horizontal well.The result shows that the permeability of reservoirs severely affects gas production rate,and the maximum gas production amount of a 20-m-long horizontal well can reach186.8 m3/day during the 5-year hydrate production.Reservoirs with smaller slope angles show higher gas production rates.The depressurization propagation and hydrate dissociation mainly develop along the direction parallel to the slope.Besides,the mean effective stress of reservoirs is concentrated in the near-wellbore area with the on-going hydrate production,and gradually decreases with the increase of the slope angle.Different from the effective stress distribution law,the total reservoir settlement amount first decreases and then increases with the increase of the slope angle.The maximum settlement of reservoirs with a 0°slope angle is up to 3.4 m,and the displacement in the near-wellbore area is as high as2.2 m after 5 years of hydrate production.It is concluded that the pore pressure drop region of low-permeability reservoirs in the South China Sea is limited,and various slope angles further lead to differences in effective stress and strain of reservoirs during hydrate production,resulting in severe uneven settlement of reservoirs. 展开更多
关键词 effective stress low‐permeability reservoirs natural gas hydrate production numerical simulation SETTLEMENT slope angle the South China
下载PDF
Corrosion resistance of Mg-Al-LDH steam coating on AZ80 Mg alloy:Effects of citric acid pretreatment and intermetallic compounds 被引量:2
3
作者 Jin-Meng Wang xiang sun +6 位作者 Liang Song M.Bobby Kannan Fen Zhang Lan-Yue Cui Yu-Hong Zou Shuo-Qi Li Rong-Chang Zeng 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第8期2967-2979,共13页
In this study,the effects of intermetallic compounds(Mg_(17)Al_(12)and Al_(8)Mn_(5))on the Mg-Al layered double hydroxide(LDH)formation mechanism and corrosion behavior of an in-situ LDH/Mg(OH)_(2)steam coatings on AZ... In this study,the effects of intermetallic compounds(Mg_(17)Al_(12)and Al_(8)Mn_(5))on the Mg-Al layered double hydroxide(LDH)formation mechanism and corrosion behavior of an in-situ LDH/Mg(OH)_(2)steam coatings on AZ80 Mg alloy were investigated.Citric acid(CA)was used to activate the alloy surface during the pretreatment process.The alloy was first pretreated with CA and then subjected to a hydrothermal process using ultrapure water to produce Mg-Al-LDH/Mg(OH)_(2)steam coating.The effect of different time of acid pretreatment on the activation of the intermetallic compounds was investigated.The microstructure and elemental composition of the obtained coatings were analyzed using FE-SEM,EDS,XRD and FT-IR.The corrosion resistance of the coated samples was evaluated using different techniques,i.e.,potentiodynamic polarization(PDP),electrochemical impedance spectrum(EIS)and hydrogen evolution test.The results indicated that the CA pretreatment significantly influenced the activity of the alloy surface by exposing the intermetallic compounds.The surface area fraction of Mg_(17)Al_(12)and Al_(8)Mn_(5)phases on the surface of the alloy was significantly higher after the CA pretreatment,and thus promoted the growth of the subsequent Mg-Al-LDH coatings.The CA pretreatment for 30 s resulted in a denser and thicker LDH coating.Increase in the CA pretreatment time significantly led to the improvement in corrosion resistance of the coated AZ80 alloy.The corrosion current density of the coated alloy was lower by three orders of magnitude as compared to the uncoated alloy. 展开更多
关键词 Magnesium alloy Citric acid pretreatment Steam coating Layered double hydroxide Intermetallic compounds Corrosion resistance
下载PDF
“互联网+”背景下智慧教学模式设计与实践 被引量:3
4
作者 孙翔 罗巾 +2 位作者 林海英 冯庆革 梁艳 《中国教育信息化》 2023年第10期93-101,共9页
智慧教育是一种基于新兴信息技术的教育模式,它将互联网、大数据、人工智能等技术应用于教学中,旨在实现教育的个性化、智能化和互动化。随着技术的不断发展,智慧教育正逐渐成为高等教育领域改革的重要方向。智慧教学快速发展主要体现... 智慧教育是一种基于新兴信息技术的教育模式,它将互联网、大数据、人工智能等技术应用于教学中,旨在实现教育的个性化、智能化和互动化。随着技术的不断发展,智慧教育正逐渐成为高等教育领域改革的重要方向。智慧教学快速发展主要体现在智慧教育理论内涵的丰富、智慧教学平台与关键技术的创新、智慧教学主体的变革、智慧教学模式的设计和多维评价体系的构建。为顺应时代的发展,智慧教学产生线上智慧教学模式和混合教学模式(轻型智慧教学、深度智慧教学),混合教学模式结合线上和线下教学的优势,更好地实现教学的互动性和实效性。从多角度阐述智慧教育内涵、智慧教学平台,以及智慧教学要素的发展,设计出适应高等教育教学实情的教学模式和评价体系,为积极推进高等教育改革、打造新型智慧教学整体提供建议。 展开更多
关键词 互联网+ 智慧教学 网络学习 高等教育 多维评价
下载PDF
Molecular dynamics study of thermal conductivities of cubic diamond,lonsdaleite,and nanotwinned diamond via machine-learned potential
5
作者 熊佳豪 戚梓俊 +6 位作者 梁康 孙祥 孙展鹏 汪启军 陈黎玮 吴改 沈威 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第12期594-601,共8页
Diamond is a wide-bandgap semiconductor with a variety of crystal configurations,and has the potential applications in the field of high-frequency,radiation-hardened,and high-power devices.There are several important ... Diamond is a wide-bandgap semiconductor with a variety of crystal configurations,and has the potential applications in the field of high-frequency,radiation-hardened,and high-power devices.There are several important polytypes of diamonds,such as cubic diamond,lonsdaleite,and nanotwinned diamond(NTD).The thermal conductivities of semiconductors in high-power devices at different temperatures should be calculated.However,there has been no reports about thermal conductivities of cubic diamond and its polytypes both efficiently and accurately based on molecular dynamics(MD).Here,using interatomic potential of neural networks can provide obvious advantages.For example,comparing with the use of density functional theory(DFT),the calculation time is reduced,while maintaining high accuracy in predicting the thermal conductivities of the above-mentioned three diamond polytypes.Based on the neuroevolution potential(NEP),the thermal conductivities of cubic diamond,lonsdaleite,and NTD at 300 K are respectively 2507.3 W·m^(-1)·K^(-1),1557.2 W·m^(-1)·K^(-1),and 985.6 W·m^(-1)·K^(-1),which are higher than the calculation results based on Tersoff-1989 potential(1508 W·m^(-1)·K^(-1),1178 W·m^(-1)·K^(-1),and 794 W·m^(-1)·K^(-1),respectively).The thermal conductivities of cubic diamond and lonsdaleite,obtained by using the NEP,are closer to the experimental data or DFT data than those from Tersoff-potential.The molecular dynamics simulations are performed by using NEP to calculate the phonon dispersions,in order to explain the possible reasons for discrepancies among the cubic diamond,lonsdaleite,and NTD.In this work,we propose a scheme to predict the thermal conductivity of cubic diamond,lonsdaleite,and NTD precisely and efficiently,and explain the differences in thermal conductivity among cubic diamond,lonsdaleite,and NTD. 展开更多
关键词 DIAMOND neuroevolution potential molecular dynamics thermal conductivity phonon transport
下载PDF
A Cooperative Security Monitoring Mechanism Aided by Optimal Multiple Slave Cluster Heads for UASNs
6
作者 Yougan Chen Wei Wang +3 位作者 xiang sun Yi Tao Zhenwen Liu Xiaomei Xu 《China Communications》 SCIE CSCD 2023年第5期148-169,共22页
As each cluster head(CH)sensor node is used to aggregate,fuse,and forward data from different sensor nodes in an underwater acoustic sensor network(UASN),guaranteeing the data security in a CH is very critical.In this... As each cluster head(CH)sensor node is used to aggregate,fuse,and forward data from different sensor nodes in an underwater acoustic sensor network(UASN),guaranteeing the data security in a CH is very critical.In this paper,a cooperative security monitoring mechanism aided by multiple slave cluster heads(SCHs)is proposed to keep track of the data security of a CH.By designing a low complexity“equilateral triangle algorithm(ETA)”,the optimal SCHs(named as ETA-based multiple SCHs)are selected from the candidate SCHs so as to improve the dispersion and coverage of SCHs and achieve largescale data security monitoring.In addition,by analyzing the entire monitoring process,the close form expression of the probability of the failure attack identification for the SCHs with respect to the probability of attack launched by ordinary nodes is deduced.The simulation results show that the proposed optimal ETA-based multiple SCH cooperation scheme has lower probability of the failure attack identification than that of the existing schemes.In addition,the numerical simulation results are consistent with the theoretical analysis results,thus verifying the effectiveness of the proposed scheme. 展开更多
关键词 underwater acoustic sensor networks data security cluster head nodes optimal location distribution of multiple slave cluster head nodes
下载PDF
A Study on Computer Consciousness on Intuitive Geometry Based on Mathematics Experiments and Statistical Analysis 被引量:1
7
作者 xiang sun Zhenbing Zeng 《Advances in Pure Mathematics》 2021年第8期671-686,共16页
In this paper, we present our research on building computing machines consciousness about intuitive geometry based on mathematics experiments and statistical inference. The investigation consists of the following five... In this paper, we present our research on building computing machines consciousness about intuitive geometry based on mathematics experiments and statistical inference. The investigation consists of the following five steps. At first, we select a set of geometric configurations and for each configuration we construct a large amount of geometric data as observation data using dynamic geometry programs together with the pseudo-random number generator. Secondly, we refer to the geometric predicates in the algebraic method of machine proof of geometric theorems to construct statistics suitable for measuring the approximate geometric relationships in the observation data. In the third step, we propose a geometric relationship detection method based on the similarity of data distribution, where the search space has been reduced into small batches of data by pre-searching for efficiency, and the hypothetical test of the possible geometric relationships in the search results has be performed. In the fourth step, we explore the integer relation of the line segment lengths in the geometric configuration in addition. At the final step, we do numerical experiments for the pre-selected geometric configurations to verify the effectiveness of our method. The results show that computer equipped with the above procedures can find out the hidden geometric relations from the randomly generated data of related geometric configurations, and in this sense, computing machines can actually attain certain consciousness of intuitive geometry as early civilized humans in ancient Mesopotamia. 展开更多
关键词 Intuitive Geometry Distribution Similarity Wasserstein Distance Mechanical Geometry Theorem-Proving
下载PDF
Fourier Locally Linear Soft Constrained MACE for facial landmark localization 被引量:1
8
作者 Wenming Yang xiang sun +2 位作者 Weihong Deng Chi Zhang Qingmin Liao 《CAAI Transactions on Intelligence Technology》 2016年第3期241-248,共8页
This paper proposes a novel nonlinear correlation filter for facial landmark localization. Firstly, we prove that SVM as a classifier can also be used for localization. Then, soft constrained Minimum Average Correlati... This paper proposes a novel nonlinear correlation filter for facial landmark localization. Firstly, we prove that SVM as a classifier can also be used for localization. Then, soft constrained Minimum Average Correlation Energy filter (soft constrained MACE) is proposed, which is more resistent to overfittings to training set than other variants of correlation filter. In order to improve the performance for the multi-mode of the targets, locally linear framework is introduced to our model, which results in Fourier Locally Linear Soft Constraint MACE (FL^2 SC-MACE). Furthermore, we formulate the fast implementation and show that the time consumption in test process is independent of the number of training samples. The merits of our method include accurate localization performance, desiring generalization capability to the variance of objects, fast testing speed and insensitivity to parameter settings. We conduct the cross-set eye localization experiments on challenging FRGC, FERET and BioID datasets. Our method surpasses the state-of-arts especially in pixelwise accuracy. 展开更多
关键词 Facial landmark localization OVERFITTING MULTIMODE FL^2 SC-MACE
下载PDF
Toxoplasmosis-Associated Secondary Hemophagocytic Syndrome: A Case Report and Literature Review
9
作者 xiang sun Jiakui Zhang +8 位作者 Qianling Ye Fan Wu Yinwei Li Qianshan Tao Qing Zhang Weiwei Zhu Huiping Wang Jinli Zhu Zhimin Zhai 《Open Journal of Blood Diseases》 2020年第3期61-70,共10页
<b style="line-height:1.5;"><span style="font-family:Verdana;">Background</span><span style="font-family:Verdana;">:</span></b><span style="fon... <b style="line-height:1.5;"><span style="font-family:Verdana;">Background</span><span style="font-family:Verdana;">:</span></b><span style="font-family:'';line-height:1.5;"><span style="font-family:Verdana;"> Toxoplasmosis is an extremely rare disease that occurs in the hosts contact with cat and dog frequently. Most human acute infections go unnoticed in immunocompetent individuals, and gradually transformed into chronic infection. However, while host immunity significantly waned, the risk of reactivation of chronic toxoplasma infection is greatly increased. Reactivation of latent toxoplasmic infection often presents with fever, leukopenia, thrombocytopenia, neurological signs and pneumonia. However, for the non-specific clinical and biological signs and its fetal outcome, toxoplasmosis is often misdiagnosed and only revealed at autopsy. </span><b><span style="font-family:Verdana;">Case Presenation</span></b></span><b style="line-height:1.5;"><span style="font-family:Verdana;">:</span></b><span style="line-height:1.5;font-family:Verdana;"> We report a case hospitalized for a week history of cough, anorexia and fatigue with nasal bleeding for a day. After hospitalization, broad-spectrum antibiotherapy was started without a clear diagnosis of infection. Then the patient did a lot of investigation</span><span style="line-height:1.5;font-family:Verdana;">s</span><span style="line-height:1.5;font-family:Verdana;"> to search the cause of infection, but there were no positive findings. However, an unexpected discovery was detected from peripheral blood smears, shows 1</span><span style="font-family:'';line-height:1.5;"> </span><span style="line-height:1.5;font-family:Verdana;">-</span><span style="font-family:'';line-height:1.5;"> </span><span style="line-height:1.5;font-family:Verdana;">3</span><span style="font-family:'';line-height:1.5;"> </span><span style="font-family:'';line-height:1.5;"><span style="font-family:Verdana;">μm in diameter, scattered, short and bow like microorganisms on Day 39 of hospitalization. Combined with the medical history and clinical manifestation, toxoplasmosis was diagnosed finally. Unfortunately, secondary hemophagocytic syndrome (HPS) was diagnosed only two days after targeted anti-infection therapy, and the patient died on Day 45 of hospitalization. </span><b><span style="font-family:Verdana;">Conclusions</span></b></span><b style="line-height:1.5;"><span style="font-family:Verdana;">:</span><span style="font-family:'';"> </span></b><span style="line-height:1.5;font-family:Verdana;">Patient with unexplained long-term fever and neurological symptoms, interstitial pneumonitis or myocarditis, toxoplasmosis should be positively considered. Only early diagnosis and treatment can increase the possibility of a successful cure and avoid other secondary diseases. 展开更多
关键词 TOXOPLASMOSIS INFECTION REACTIVATION Hemophagocytic Syndrome
下载PDF
青龙矿田兰旗组火山岩岩石学、地球化学特征及成因探讨
10
作者 李国臣 孙祥 +1 位作者 罗毅 谷勇 《自然科学》 2015年第2期40-48,共9页
青龙铀矿田中侏罗统兰旗组为一套较厚中性火山熔岩–火山碎屑岩,是含矿层上覆最重要保护层。基于火山岩相学特征将兰旗组划分为3段:下段安山集块岩、安山角砾岩、及碎斑安山岩、安山岩;中段紫红色凝灰质砂岩、砾岩;上段气孔状安山岩夹... 青龙铀矿田中侏罗统兰旗组为一套较厚中性火山熔岩–火山碎屑岩,是含矿层上覆最重要保护层。基于火山岩相学特征将兰旗组划分为3段:下段安山集块岩、安山角砾岩、及碎斑安山岩、安山岩;中段紫红色凝灰质砂岩、砾岩;上段气孔状安山岩夹薄层黑云母晶屑凝灰岩。对各层位的火山熔岩进行了岩石地球化学分析,结果显示总体具有低镁低钛高铝高钾特征,属准铝质系列和高钾钙碱性系列;稀土元素、相容元素、不相容元素等显示下地壳岩浆混入幔源特征,并显示了各阶段混染程度存在强–弱–强演化趋势;岩浆成因并非大规模结晶分异,可能主要为部分熔融;其形成构造背景为板内造山环境,处于地壳缩短加厚晚期向减薄转换阶段。 展开更多
关键词 兰旗组 中性火山岩 岩石学 地球化学 成因
下载PDF
Stress increases MHC-I expression in dopaminergic neurons and induces autoimmune activation in Parkinson’s disease 被引量:4
11
作者 Bao-Yan Wang Yong-Yi Ye +6 位作者 Chen Qian Hong-Bo Zhang Heng-Xu Mao Long-Ping Yao xiang sun Guo-Hui Lu Shi-Zhong Zhang 《Neural Regeneration Research》 SCIE CAS CSCD 2021年第12期2521-2527,共7页
The expression of major histocompatibility complex class I(MHC-I),a key antigen-presenting protein,can be induced in dopaminergic neurons in the substantia nigra,thus indicating its possible involvement in the occurre... The expression of major histocompatibility complex class I(MHC-I),a key antigen-presenting protein,can be induced in dopaminergic neurons in the substantia nigra,thus indicating its possible involvement in the occurrence and development of Parkinson’s disease.However,it remains unclear whether oxidative stress induces Parkinson’s disease through the MHC-I pathway.In the present study,polymerase chain reaction and western blot assays were used to determine the expression of MHC-I in 1-methyl-4-phenylpyridinium(MPP+)-treated SH-SY5Y cells and a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)-induced Parkinson’s disease mouse model.The findings revealed that MHC-I was expressed in both models.To detect whether the expression of MHC-I was able to trigger the infiltration of cytotoxic T cells,immunofluorescence staining was used to detect cytotoxic cluster of differentiation 8(CD8)+T cell infiltration in the substantia nigra of MPTP-treated mice.The results indicated that the presentation of MHC-I in dopaminergic neurons was indeed accompanied by an increase in the number of CD8+T cells.Moreover,in MPTP-induced Parkinson’s disease model mice,the genetic knockdown of endogenous MHC-I,which was caused by injecting specific adenovirus into the substantia nigra,led to a significant reduction in CD8+T cell infiltration and alleviated dopaminergic neuronal death.To further investigate the molecular mechanisms of oxidative stress-induced MHC-I presentation,the expression of PTEN-induced kinase 1(PINK1)was silenced in MPP+-treated SH-SY5Y cells using specific small interfering RNA(siRNA),and there was more presentation of MHC-I in these cells compared with control siRNA-treated cells.Taken together,MPP+-/MPTP-induced oxidative stress can trigger MHC-I presentation and autoimmune activation,thus rendering dopaminergic neurons susceptible to immune cells and degeneration.This may be one of the mechanisms of oxidative stress-induced Parkinson’s disease,and implies the potential neuroprotective role of PINK1 in oxidative stress-induced MHC-I presentation.All animal experiments were approved by the Southern Medical University Ethics Committee(No.81802040,approved on February 25,2018). 展开更多
关键词 antigen presentation AUTOIMMUNE CD8+T cell dopaminergic neuron major histocompatibility complex class I mitochondria NEUROINFLAMMATION oxidative stress Parkinson’s disease PINK1
下载PDF
Crucial control on magmatic-hydrothermal Sn deposit in the Tengchong block,SW China:Evidence from magma differentiation and zircon geochemistry 被引量:4
12
作者 Qiwei Zhang Qingfei Wang +3 位作者 Gongjian Li xiang sun Qihai Shu Jun Deng 《Geoscience Frontiers》 SCIE CAS CSCD 2022年第4期129-143,共15页
Magmatic-hydrothermal Sn deposits are commonly associated with high silica magmas,but why most global high silica granites do not bear economic Sn ore grades remains unclear.Two crucial factors controlling magmatic-hy... Magmatic-hydrothermal Sn deposits are commonly associated with high silica magmas,but why most global high silica granites do not bear economic Sn ore grades remains unclear.Two crucial factors controlling magmatic-hydrothermal Sn mineralization,including advanced fractionation and depressurization-induced rapid cooling,were revealed in the case study of the Guyong granitic pluton linked with the Xiaolonghe Sn deposit,in the Tengchong block,SW China.The Guyong granitic pluton comprises three petrological facies:less evolved biotite syenogranite,evolved alkali granite and leucogranite,and highly evolved facies(the protolith of greisenized granite).Similar crystallization ages(~77 Ma)and gradual contact between different petrological facies indicate the Guyong granitic pluton records a continuous fractionation process.Monte Carlo-revised Rayleigh fractionation model suggests the fractionation degree of the Guyong pluton is markedly high(>87 wt.%)that can only be achieved by a high initial water(≥4 wt.%)content in the parent granitic magma revealed by rhyolite-MELTS calculation.Advanced degree fractionation causes the first Sn enrichment but it also significantly increases the viscosity of evolved magmas,suppressing the exsolution and transport of hydrothermal fluids.Hence,it must be compensated by the second critical factor:depressurization-induced rapid cooling,reflected by the occurrence of highly metamict zircons in the greisenized granite.The highly metamict feature,indicated by the large full width at half maximum(FWHM)values of zirconν3(SiO_(4)) peak(>19.5 cm^(-1)),suggests these zircons do not experience thermal annealing but rapidly ascend into a shallow cooling environment.Depressurization-induced rapid cooling facilitates exsolution and transport of hydrothermal fluids,interacting with wall rocks and resulting in Sn mineralization. 展开更多
关键词 Magmatic-hydrothermal Sn deposits Metamict zircons Fractionation Raman spectra Thermodynamic modeling
下载PDF
A theoretical study of electrocatalytic ammonia synthesis on single metal atom/MXene 被引量:3
13
作者 Yijing Gao Han Zhuo +6 位作者 Yongyong Cao xiang sun Guilin Zhuang Shengwei Deng Xing Zhong Zhongzhe Wei Jianguo Wang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第2期152-159,共8页
Electrocatalytic ammonia synthesis under mild conditions is an attractive and challenging process in the earth’s nitrogen cycle,which requires efficient and stable catalysts to reduce the overpotential.The N2 activat... Electrocatalytic ammonia synthesis under mild conditions is an attractive and challenging process in the earth’s nitrogen cycle,which requires efficient and stable catalysts to reduce the overpotential.The N2 activation and reduction overpotential of different Ti3C2O2-supported transition metal(TM)(Sc,Ti,V,Cr,Mn,Fe,Co,Ni,Cu,Zn,Mo,Ru,Rh,Pd,Ag,Cd,and Au)single-atom catalysts have been analyzed in terms of the Gibbs free energies calculated using the density functional theory(DFT).The end-on N2 adsorption was more energetically favorable,and the negative free energies represented good N2 activation performance,especially in the presence Fe/Ti3C2O2(﹣0.75 eV).The overpotentials of Fe/Ti3C2O2,Co/Ti3C2O2,Ru/Ti3C2O2,and Rh/Ti3C2O2 were 0.92,0.89,1.16,and 0.84 eV,respectively.The potential required for ammonia synthesis was different for different TMs and ranged from 0.68 to 2.33 eV.Two possible potential-limiting steps may be involved in the process:(i)hydrogenation of N2 to*NNH and(ii)hydrogenation of*NH2 to ammonia.These catalysts can change the reaction pathway and avoid the traditional N–N bond-breaking barrier.It also simplifies the understanding of the relationship between the Gibbs free energy and overpotential,which is a significant factor in the rational designing and large-scale screening of catalysts for the electrocatalytic ammonia synthesis. 展开更多
关键词 Electrocatalytic ammonia synthesis Single atom catalyst MXene Transition metal Density functional theory OVERPOTENTIAL Gibbs free energy
下载PDF
Influence of intermetallic Al-Mn particles on in-situ steam Mg-Al-LDH coating on AZ31 magnesium alloy 被引量:3
14
作者 Feng LI xiang sun +7 位作者 Liang SONG M.Bobby KANNAN Fen ZHANG Lan-yue CUI Yu-hong ZOU Shuo-qi LI Cheng-bao LIU Rong-chang ZENG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第12期3926-3949,共24页
The influence of intermetallic Al-Mn particles on the corrosion behavior of in-situ formed Mg-Al layered double hydroxide(Mg-Al-CO32--LDH)steam coating on AZ31 Mg alloy was investigated.The alloy was pretreated with H... The influence of intermetallic Al-Mn particles on the corrosion behavior of in-situ formed Mg-Al layered double hydroxide(Mg-Al-CO32--LDH)steam coating on AZ31 Mg alloy was investigated.The alloy was pretreated with H3PO4,HCl,HNO3or citric acid(CA),followed by hydrothermal treatment,for the fabrication of Mg-Al-LDH coating.The microstructure,composition and corrosion resistance of the coated samples were investigated.The results showed that the surface area fraction of Al-Mn phase exposed on the surface of the alloy was significantly increased after CA pretreatment,which promotes the growth of the Mg-Al-LDH steam coating.Further,the LDH-coated alloy pretreated with CA possessed the most compact surface and the maximum coating thickness among all the coatings.The corrosion current density of the coated alloy was decreased by three orders of magnitude as compared to that of the bare alloy. 展开更多
关键词 magnesium alloy acid pretreatment layered double hydroxide intermetallic particles steam coating corrosion resistance
下载PDF
Computational screening of O‐functional MXenes for electrocatalytic ammonia synthesis 被引量:2
15
作者 Yijing Gao Shijie Zhang +9 位作者 xiang sun Wei Zhao Han Zhuo Guilin Zhuang Shibin Wang Zihao Yao Shengwei Deng Xing Zhong Zhongzhe Wei Jian‐guo Wang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2022年第7期1860-1869,共10页
The nitrogen reduction reaction(NRR)using new and efficient electrocatalysts is a promising al‐ternative to the traditional Haber‐Bosch process.Nevertheless,it remains a challenge to design efficient catalysts with ... The nitrogen reduction reaction(NRR)using new and efficient electrocatalysts is a promising al‐ternative to the traditional Haber‐Bosch process.Nevertheless,it remains a challenge to design efficient catalysts with improved catalytic performance.Herein,various O‐functional MXenes were investigated as NRR catalysts by a combination of density functional theory calculations and least absolute shrinkage and selection operator(LASSO)regression.Nb_(3)C_(2)O_(X) has been regarded as a promising catalyst for the NRR because of its stability,activity,and selectivity.The poten‐tial‐determining step is*NH_(2) hydrogenation to*NH3 with a limiting potential of-0.45 V.Further‐more,via LASSO regression,the descriptors and equations fitting the relationship between the properties of O‐functional MXenes and NRR activity have been proposed.This work not only pro‐vides a rational design strategy for catalysts but also provides machine learning data for further investigation. 展开更多
关键词 Electrocatalytic ammonia synthesis O‐functional MXenes Density functional theory Least absolute shrinkage and selection operator regression Gibbs free energy
下载PDF
The Effect of Low Temperature and High Temperature on Flowering and Pollination of Red Cartridge Kiwifruit in Western Guizhou in Early Spring of 2021 被引量:4
16
作者 Tianfu HUANG Zaixiang CHI +2 位作者 Yue TIAN xiang sun Lijuan LIU 《Meteorological and Environmental Research》 CAS 2021年第3期89-93,共5页
Based on the daily average temperature from March 19 to April 2,2021 at three surface meteorological stations in western Guizhou and the daily average temperature,maximum temperature and minimum temperature from March... Based on the daily average temperature from March 19 to April 2,2021 at three surface meteorological stations in western Guizhou and the daily average temperature,maximum temperature and minimum temperature from March 19 to April 2,2021 at 12 main automatic meteorological stations of red cartridge kiwifruit base,the effects of low temperature and high temperature on flowering and pollination of red cartridge kiwifruit in early spring of 2021 were analyzed.The results showed that slight cold spell in later spring in western Guizhou occurred from March 21 to 23.The lower limit of the daily average temperature required for flowering period(12℃or below)appeared in each base of red cartridge kiwifruit during March 21-23,which affected the red cartridge kiwifruit trees in Faer,Houchang,Miluo,Shunchang,Panlong and Jichang bases flowering and pollinating before March 20.From March 29 to April 2,the daily maximum temperature of Faer and other eleven bases was 30℃or above,which caused the wilting and abscission of flowers and young fruits of of red cartridge kiwifruit trees in Faer,Houchang,Miluo,Shunchang,Panlong,shaomi,Jichang and Aga bases blooming and pollinating before March 24,but the flowers of red cartridge kiwifruit trees in Langdai,Longhe,Pugu and Shuangfeng bases blooming and pollinating after March 28 were not damaged. 展开更多
关键词 Flowering stage Pollination stage Cold temperature High temperature Influence
下载PDF
Enhanced oxygen reduction reaction performance over Pd catalysts by oxygen-surface-modified SiC 被引量:1
17
作者 Jing Li xiang sun +3 位作者 Yongzheng Duan Dongmei Jia Yuejin Li Jianguo Wang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第6期963-970,共8页
Obtaining a detailed understanding of the surface modification of supports is crucial;however,it is a challenging task for the development and large-scale fabrication of supported electrocatalysts that can be used as ... Obtaining a detailed understanding of the surface modification of supports is crucial;however,it is a challenging task for the development and large-scale fabrication of supported electrocatalysts that can be used as alternatives to Pt-based catalysts for the oxygen reduction reaction(ORR).In this study,commercial silicon carbide(SiC)was modified through surface oxidization(O-SiC)to support the use of Pd nanoparticles(Pd NPs)as electrocatalysts for ORR.The obtained Pd/O-SiC catalysts exhibited better ORR activity,stronger durability,and higher resistance to methanol poisoning than that exhibited by commercial Pt/C.The role of the support in enhancing the ORR performance,especially the oxidization of SiC surfaces,was discussed in detail based on the experimental characterizations and density functional theory calculations.The underlying mechanism of the superior ORR performance of Pd/O-SiC catalysts was attributed to the charge transfer from SiC_(x)O_(y)to Pd NPs on the surfaces of SiC and the strong metal–support interactions(SMSIs)between Pd and SiC_(x)O_(y).The charge transfer enhanced the ORR activity by inducing electron-rich Pd,increased the adsorption of the key intermediate OOH,and decreased the Gibbs free energy of the critical ORR step.Furthermore,SMSIs enhanced the ORR stability of the Pd/O-SiC catalyst.This study provided a facile route for designing and developing highly active Pd-based ORR electrocatalysts. 展开更多
关键词 Silicon carbide Surface oxidization Oxygen reduction reaction Density functional theory Charge transfer Electron-rich Pd
下载PDF
Synergistic effect of size-dependent PtZn nanoparticles and zinc single-atom sites for electrochemical ozone production in neutral media 被引量:1
18
作者 Bowen Yuan Zihao Yao +7 位作者 Chenlong Qiu Haiyang Zheng Yilong Yan Qiaoqiao Zhang xiang sun Yu Gu Xing Zhong Jianguo Wang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2020年第12期312-322,共11页
Electrochemical ozone production(EOP) via water electrolysis represents an attractive method for the generation of high-purity O3. Herein, the X-PtZn/Zn-N-C electrocatalysts show a strong structural sensitive behavior... Electrochemical ozone production(EOP) via water electrolysis represents an attractive method for the generation of high-purity O3. Herein, the X-PtZn/Zn-N-C electrocatalysts show a strong structural sensitive behavior depends on the size of the PtZn nanoparticles and their EOP activity exhibits a volcano-type dependence for the O3 performance in neutral media. The 7.7-PtZn/Zn-N-C exhibits EOP current efficiency of 4.2%, and shows the prominent performance in the production of gaseous O3 with a value of 1647 ppb at 30 min, which is almost 4-fold compared to 2.2-Pt Zn/Zn-N-C. Based on the experiments and theoretical calculations, the performance of the EOP process was determined by the nanoparticle size-effect and the synergistic effect between the PtZn nanoparticles and atomically dispersed Zn-N-C. Furthermore, the fivemembered cyclic structure of O3 can be stabilized between the PtZn nanoparticle and the Zn-N-C support,indicating that O3 is produced at the interface. 展开更多
关键词 Electrochemical ozone production PtZn Single-atom catalysts Size effect Synergistic effect
下载PDF
ED-SWE:Event detection based on scoring and word embedding in online social networks for the internet of people 被引量:1
19
作者 xiang sun Lu Liu +1 位作者 Ayodeji Ayorinde John Panneerselvam 《Digital Communications and Networks》 SCIE CSCD 2021年第4期559-569,共11页
Online social media networks are gaining attention worldwide,with an increasing number of people relying on them to connect,communicate and share their daily pertinent event-related information.Event detection is now ... Online social media networks are gaining attention worldwide,with an increasing number of people relying on them to connect,communicate and share their daily pertinent event-related information.Event detection is now increasingly leveraging online social networks for highlighting events happening around the world via the Internet of People.In this paper,a novel Event Detection model based on Scoring and Word Embedding(ED-SWE)is proposed for discovering key events from a large volume of data streams of tweets and for generating an event summary using keywords and top-k tweets.The proposed ED-SWE model can distill high-quality tweets,reduce the negative impact of the advent of spam,and identify latent events in the data streams automatically.Moreover,a word embedding algorithm is used to learn a real-valued vector representation for a predefined fixed-sized vocabulary from a corpus of Twitter data.In order to further improve the performance of the Expectation-Maximization(EM)iteration algorithm,a novel initialization method based on the authority values of the tweets is also proposed in this paper to detect live events efficiently and precisely.Finally,a novel automatic identification method based on the cosine measure is used to automatically evaluate whether a given topic can form a live event.Experiments conducted on a real-world dataset demonstrate that the ED-SWE model exhibits better efficiency and accuracy than several state-of-art event detection models. 展开更多
关键词 Internet of people Hyperlink-induced topic search Event detection Online social networks
下载PDF
传统孝文化对城市家庭养老的启示 被引量:2
20
作者 孙翔 孟瑞霞 雒季 《西北成人教育学院学报》 2020年第5期53-56,共4页
家庭养老作为中国最古老、最基本、最人性化的的养老方式,其赖以存在的思想基础就是传统孝文化。但随着现代家庭结构的变化、人口老龄化的加剧等,我国传统的家庭养老尤其是城市家庭养老面临着严峻的挑战,城市家庭养老的困境主要表现在... 家庭养老作为中国最古老、最基本、最人性化的的养老方式,其赖以存在的思想基础就是传统孝文化。但随着现代家庭结构的变化、人口老龄化的加剧等,我国传统的家庭养老尤其是城市家庭养老面临着严峻的挑战,城市家庭养老的困境主要表现在精神慰藉、生活照料以及经济供养方面,而消解这一困境,以养老、尊老、敬老作为其基本含义的传统孝文化无疑具有重要的启示,可以为当前城市家庭养老提供可选择的思想资源。 展开更多
关键词 传统孝文化 城市家庭 养老
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部