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A force transfer mechanism for triggering landslides during rainfall infiltration 被引量:6
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作者 LIU Gang TONG Fu-guo +1 位作者 ZHAO Yi-tong TIAN Bin 《Journal of Mountain Science》 SCIE CSCD 2018年第11期2480-2491,共12页
Shallow slope failures induced by rainfall infiltration occur frequently, and the relevant triggering mechanisms have been widely studied.Rainfall-induced landslides are widely recognized to be caused by increases in ... Shallow slope failures induced by rainfall infiltration occur frequently, and the relevant triggering mechanisms have been widely studied.Rainfall-induced landslides are widely recognized to be caused by increases in soil weight, seepage force and pore water pressure or decreases in soil mechanical properties. However, even when all these factors are considered, some landslides still cannot be explained well. The increased pore water pressure in a slope reduces the effective stress of the soil and may trigger slope failure. Similarly, the pore gas pressure in a slope also reduces the effective stress of the soil but has been neglected in previous studies. As the viscosity of air is nearly negligible when compared with that of water, the pore gas pressure spreads faster, and its influence is wider, which is harmful for the stability of the slope. In this paper, the effects of pore gas pressure are considered in a shallow slope stability analysis, and a self-designed experiment is conducted to validate the force transfer mechanism.Numerical simulation results show that the pore gas pressure in the slope increases sharply at different locations under heavy rainfall conditions and that the pore gas pressure causes a rapid decrease in the slope safety factor. Laboratory experimental results show that the pore gas pressure throughout the whole unsaturated zone has the same value, which indicates that the gas pressure could spread quickly to the whole sample. 展开更多
关键词 LANDSLIDE Force transfer mechanism Rainfall infiltration Water-air two-phase flow
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Mass transfer mechanism and relationship of gas–liquid annular flow in a microfluidic cross-junction device 被引量:1
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作者 Xin Xu Na Xu +3 位作者 Wei Zhang Junwen Wang Yao Li Chen Yang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第12期37-48,共12页
Mass transfer performance of gas–liquid two-phase flow at microscale is the basis of application of microreactor in gas–liquid reaction systems.At present,few researches on the mass transfer property of annular flow... Mass transfer performance of gas–liquid two-phase flow at microscale is the basis of application of microreactor in gas–liquid reaction systems.At present,few researches on the mass transfer property of annular flow have been reported.Therefore,the mass transfer mechanism and relationship of gas–liquid annular flow in a microfluidic cross-junction device are studied in the present study.We find that the main factors,i.e.,flow pattern,liquid film thickness,liquid hydraulic retention time,phase interface fluctuation,and gas flow vorticity,which influence the flow mass transfer property,are directly affected both by gas and liquid flow velocities.But the influences of gas and liquid velocities on different mass transfer influencing factors are different.Thereout,the fitting relationships between gas and liquid flow velocities and mass transfer influencing factors are established.By comparing the results from calculations using fitting equations and simulations,it shows that the fitting equations have relatively high degrees of accuracy.Finally,the Pareto front,namely the Pareto optimal solution set,of gas and liquid velocity conditions for the best flow mass transfer property is obtained using the method of multi-objective particle swarm optimization.It is proved that the mass transfer property of the gas–liquid two-phase flow can be obviously enhanced under the guidance of the obtained Pareto optimal solution set through experimental verification. 展开更多
关键词 Gas-liquid microreactor Annular flow Mass transfer mechanism Mass transfer relationship Multi-objective particle swarm optimization
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Energy transfer mechanism of Sr_4Al_(14)O_(25):Eu^(2+) phosphor 被引量:1
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作者 李群 赵军武 孙飞龙 《Journal of Rare Earths》 SCIE EI CAS CSCD 2010年第1期26-29,共4页
Long lasting blue-green-emitting Sr4Al14O25:Eu2+ phosphors were synthesized by solid-state reactions.The phosphors were investigated by X-ray diffraction(XRD) and fluorescence spectrophotometer.A pure phase of Sr4Al14... Long lasting blue-green-emitting Sr4Al14O25:Eu2+ phosphors were synthesized by solid-state reactions.The phosphors were investigated by X-ray diffraction(XRD) and fluorescence spectrophotometer.A pure phase of Sr4Al14O25:Eu2+ phosphor was obtained at 1250 °C.There are two different types of Eu emission centers in Sr4Al14O25:Eu2+ phosphor.The effects of the Eu2+ concentration and the reducing temperature on the distribution of Eu2+ among different sites were investigated.The energy transfer mechanism between... 展开更多
关键词 Sr4Al14O25:Eu2+ PHOSPHOR phase transition energy transfer mechanism rare earths
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Uplift behavior and load transfer mechanism of prestressed high-strength concrete piles 被引量:1
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作者 赖颖 金国芳 《Journal of Central South University》 SCIE EI CAS 2010年第1期136-141,共6页
Prestressed high-strength-concrete (PHC) tube-shaped pile is one of the recently used foundations for soft soil. The research on uplift resistance of PHC pile is helpful to the design of pile foundations. A field-scal... Prestressed high-strength-concrete (PHC) tube-shaped pile is one of the recently used foundations for soft soil. The research on uplift resistance of PHC pile is helpful to the design of pile foundations. A field-scale test program was conducted to study the uplift behavior and load transfer mechanism of PHC piles in soft soil. The pullout load tests were divided into two groups with different diameters, and there were three piles in each group. A detailed discussion of the axial load transfer and pile skin resistance distribution was also included. It is found from the tests that the uplift capacity increases with increasing the diameter of pile. When the diameter of piles increases from 500 to 600 mm, the uplift load is increased by 51.2%. According to the load-displacement (Q-S) curves, all the piles do not reach the ultimate state at the maximum load. The experimental results show that the piles still have uplift bearing capacity. 展开更多
关键词 prestresed high-strength concrete piles full-scale test uplift capacity load transfer mechanism
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Mass and heat transfer mechanism in wood during radio frequency/vacuum drying and numerical analysis
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作者 Xiaoran Jia Jingyao Zhao Yingchun Cai 《Journal of Forestry Research》 SCIE CAS CSCD 2017年第1期205-213,共9页
The mass and heat transfer mechanisms during radio frequency/vacuum (RF/V) drying of square-edged timber were analyzed and discussed in detail, and a new one-dimensional mathematical model to describe the transport ... The mass and heat transfer mechanisms during radio frequency/vacuum (RF/V) drying of square-edged timber were analyzed and discussed in detail, and a new one-dimensional mathematical model to describe the transport phenomena of mass and heat during continuous RF/V drying was derived from conservation equations based on the mass and heat transfer theory of porous materials The new model provided a relatively fast and efficient way to simulate vacuum drying behavior assisted by dielectric heating. Its advantages compared with the conventional models include: (1) Each independent vari- able has a separate control equation and is solved inde- pendently by converting the partial differential equation into a difference equation with the finite volume method; (2) The calculated data from different parts of the specimen can be displayed in the evolution curves, and the change law of the,parameters can be better described. After analyzing the calculated results, most of the important phenomena observed during RF/V drying were adequately described by this model. 展开更多
关键词 Bulk flow Mathematical model Numerical analysis RF/V drying transfer mechanism
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THE STUDY ON THE MASS TRANSFER MECHANISM OF EUROPIUM ION THROUGH LIQUID SURFACTANT MEMBRANES
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作者 姜长印 郁建涵 朱永(贝睿) 《Chinese Journal of Chemical Engineering》 SCIE EI CAS 1985年第1期11-19,共9页
The transfer of trivalent europium ion in a liquid surfactant membrane system is investigated in order toclarify the characteristics of liquid membrane separation process and the availability of this technique forreco... The transfer of trivalent europium ion in a liquid surfactant membrane system is investigated in order toclarify the characteristics of liquid membrane separation process and the availability of this technique forrecovering trivalent lanthanides and actinides.A layered structure model for the emulsion globule is sug-gested.The equations describing the relationship among the effective membrane thickness,the time andother factors are derived and verified experimentally.Results show that under certain conditions the decreas-ing concentration of europium ion in the external phase is proportional to the square root of the time,the acidity of the internal phase and the carrier concentration in the membrane phase.The membrane phase consists of kerosene(solvent),Span-80(surfactant)and di-(2-ethylhexyl) phosphoricacid(HDEHP,carrier).The internal phase is dilute nitric acid and the external phase is aqueous solu-tion containing Eu(NO3)3.The mass transfer rate of europium in this system is high and the recovery ofeuropium may be more than 99%. 展开更多
关键词 FIGURE show Eu HAZ THE STUDY ON THE MASS transfer mechanism OF EUROPIUM ION THROUGH LIQUID SURFACTANT MEMBRANES
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Synthesis,characteristic and intramolecular energy transfer mechanism of reactive terbium complex in white light emitting diode 被引量:6
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作者 张爱琴 潘启亮 +2 位作者 贾虎生 刘旭光 许并社 《Journal of Rare Earths》 SCIE EI CAS CSCD 2012年第1期10-16,共7页
A reactive Tb(III) complex with 2-aminobenzoic acid(2-ABAH) and acrylonitrile(AN) as ligands was synthesized.The structure of the complex was characterized by elemental analysis and Fourier transform infrared sp... A reactive Tb(III) complex with 2-aminobenzoic acid(2-ABAH) and acrylonitrile(AN) as ligands was synthesized.The structure of the complex was characterized by elemental analysis and Fourier transform infrared spectrometry(FT-IR).The results indicated that the ligands were coordinated with Tb(III) ion.Thermal gravity-derivative thermogravimetric(TG-DTG) analysis indicated that the complex kept stable up to 198 oC.Luminescence properties were investigated by UV-vis absorption spectra and fluorescence spectra.The results suggested that being excited at 361 nm,the complex exhibited characteristic emission of Tb(III) ion,revealing that the complex could be excited by 365 nm ultraviolet chip.The HOMO and LUMO,ΔE(HOMO-LUMO),molecular frontier orbital,and the singlet state and triplet energy state levels of the ligands were calculated at the B3LYP/6-31+G(d) level.The results indicated that intramolecular energy transfer mechanism followed Dexter exchange energy transfer theory.Both the calculation for excited state of ligand and energy transfer mechanism could provide the theoretical basis for the design of high luminescent materials of rare earth complexes with organic ligands. 展开更多
关键词 terbium complex FLUORESCENCE quantum chemistry calculation energy transfer mechanism rare earths
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Energy transfer mechanism in Er^(3+) doped fluoride glass sensitized by Tm^(3+) or Ho^(3+) for 2.7-μm emission 被引量:2
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作者 黄飞飞 刘雪强 +2 位作者 李韦韦 胡丽丽 陈丹平 《Chinese Optics Letters》 SCIE EI CAS CSCD 2014年第5期33-36,共4页
Enhanced 2.7 μm emission is obtained in Er3+/Tma+ and Era+/Ho3+ codoped ZBYA glasses. Absorp- tion and emission spectra are tested to characterize the 2.7 μm emission properties of Era+/Tm3+ and Era+/Ho3+ do... Enhanced 2.7 μm emission is obtained in Er3+/Tma+ and Era+/Ho3+ codoped ZBYA glasses. Absorp- tion and emission spectra are tested to characterize the 2.7 μm emission properties of Era+/Tm3+ and Era+/Ho3+ doped ZBYA glasses and a reasonable energy transfer mechanism of 2.7 μm emission between Er3+ and Tm3+Ho3+) ion is proposed. Codoping of Tm3+ or Ho3+ significantly reduces the lifetime of the Era+: 4I13/2 level due to the energy transfer of Er3+:4I13/2 →Tm3+:3F4 or Er3+:4I13/2 →Ho3+: 5I7. Thus, the 2.7μm emission is strengthened and the 1,5μm emission is decreased accordingly especially in the Era+/Tma+ sample. The upconversion effects between the Er3+/Tm3+ and Er3+/Ho3+ doped ZBYA glasses are different attribute to the different energy transfer efficiencies. Both of the two codoped samples possess nearly equal large emission cross section (16.6 × 10 -21 cm-2) around 2.7 μm. The results indicate that this Er3+/Tm3+ or Er3+/Ho3+ doped ZBYA glass has potential applications in 2.7 μm laser. 展开更多
关键词 or Ho doped fluoride glass sensitized by Tm Energy transfer mechanism in Er for 2.7
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Mass transfer mechanisms in fixed-bed adsorption of erythromycin 被引量:2
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作者 Ying SUN Jiawen ZHU +2 位作者 Kui CHEN Sheng ZHU Jie XU 《Frontiers of Chemical Science and Engineering》 SCIE EI CSCD 2008年第4期353-360,共8页
The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performa... The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performance was investigated in a fixed-bed system with respect to the adsorption superficial velocity,ionic strength and pH.A mathematical model was used to simulate the mass transfer mechanism,taking film mass transfer,pore diffusion and axial dispersion into account.The model predictions were consistent with the experi-mental data and were consequently used to determine the mass transfer coefficients. 展开更多
关键词 fixed-bed adsorption superficial velocity ionic strength erythromycin However investigations on the parameters governing the performance of this technology are still scarce.In the present work a polymeric and porous resin Sepabeads SP825 resin was used for its higher adsorption efficiency compared with the resins reported.The equilib-rium capacity of Sepabeads SP825 for EM in a batch system was established using a Langmuir isotherm.The effects of superficial velocity ionic strength and pH on the adsorption process were determined from the results of fixed bed experiments.And a model of the purification process was used to simulate the mass transfer mechanism which has taken film mass transfer pore diffusion and axial dispersion into account.The experimental adsorp-tion measurements were compared to the results calcu-lated from the model.The completion of these studies provide some essential parameters which are required in order to design a successful purification process and better understand the fundamentals of these process.
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The phase transfer mechanism of 18-molybdophosphate anion at the water/nitrobenzene interface
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作者 WANG Er-Kang LIU Yu-Qing 《Acta Chimica Sinica English Edition》 SCIE CAS CSCD 1989年第2期115-121,共1页
The phase transfer mechanism of 18-molybdophosphate anion at the water/nitrobenzene interfaca has been investigated by chronopotentiometry with cyclic linear current-scanning (CLC) and cyclic voltammetry (CV). The tra... The phase transfer mechanism of 18-molybdophosphate anion at the water/nitrobenzene interfaca has been investigated by chronopotentiometry with cyclic linear current-scanning (CLC) and cyclic voltammetry (CV). The transfer species is 18-molybdophosphtae anion with a charge number of-4, H_2[P_2Mo_(18)O_(62)]^(4-). The transfer process is controlled by diffusion at a slow polarization rate and considerably influenced by pH of the aqueous phase. The stable forms and pH range of the heteropoly anion in the aqueous solution can be directly confirmed through voltammetric behavior. The theoretical analysis of the relationship between the transfer potential and solution pH is identical to the experimental results. The linear concentration relationship with the transfer peak current is suggested to be used in the determination of heteropoly acids(salts). 展开更多
关键词 The phase transfer mechanism of 18-molybdophosphate anion at the water/nitrobenzene interface
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Mechanism of Excited State Double Proton Transfer in 2-Amino-3-Methoxypyridine and Acetic Acid Complex
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作者 Qing-Chi Meng Guang-Hua Ren, +1 位作者 Song-Qiu Yang Tian-Shu Chu 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第9期87-89,共3页
The excited-state double-proton transfer (ESDPT) mechanism of 2-amino-3-methoxypyridine and acetic acid com- plex is studied by the density functional theory (DFT) and time-dependent DFT with CAM-B3LYP functional.... The excited-state double-proton transfer (ESDPT) mechanism of 2-amino-3-methoxypyridine and acetic acid com- plex is studied by the density functional theory (DFT) and time-dependent DFT with CAM-B3LYP functional. The complex is connected through two different types of inter-molecular hydrogen bonds. After photo-excitation, both hydrogen bonds get strengthened, which can facilitate the ESDPT reaction. The scanned potential energy curve along the proton transfer coordinate indicates that the ESDPT reaction proceeds in a stepwise pattern. 展开更多
关键词 LYP CAM PT MOP mechanism of Excited State Double Proton transfer in 2-Amino-3-Methoxypyridine and Acetic Acid Complex
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Emerging Flexible Thermally Conductive Films:Mechanism,Fabrication,Application 被引量:11
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作者 Chang‑Ping Feng Fang Wei +7 位作者 Kai‑Yin Sun Yan Wang Hong‑Bo Lan Hong‑Jing Shang Fa‑Zhu Ding Lu Bai Jie Yang Wei Yang 《Nano-Micro Letters》 SCIE EI CAS CSCD 2022年第8期24-57,共34页
Effective thermal management is quite urgent for electronics owing to their ever-growing integration degree,operation frequency and power density,and the main strategy of thermal management is to remove excess energy ... Effective thermal management is quite urgent for electronics owing to their ever-growing integration degree,operation frequency and power density,and the main strategy of thermal management is to remove excess energy from electronics to outside by thermal conductive materials.Compared to the conventional thermal management materials,flexible thermally conductive films with high in-plane thermal conductivity,as emerging candidates,have aroused greater interest in the last decade,which show great potential in thermal management applications of next-generation devices.However,a comprehensive review of flexible thermally conductive films is rarely reported.Thus,we review recent advances of both intrinsic polymer films and polymer-based composite films with ultrahigh in-plane thermal conductivity,with deep understandings of heat transfer mechanism,processing methods to enhance thermal conductivity,optimization strategies to reduce interface thermal resistance and their potential applications.Lastly,challenges and opportunities for the future development of flexible thermally conductive films are also discussed. 展开更多
关键词 Thermal conductivity Flexible thermally conductive films Heat transfer mechanism Interface thermal resistance Thermal management applications
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Research on Coupling Transfer Characteristics of Vibration Energy of Free Piston Linear Generator 被引量:1
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作者 Jingyi Tian Huihua Feng +1 位作者 Yifan Chen Shuochun Wang 《Journal of Beijing Institute of Technology》 EI CAS 2020年第4期556-567,共12页
In order to clarify the mechanism and main influencing factors of the vibration energy coupling transmission with a dual-piston structure,a thermodynamic and dynamic coupling model of the free piston linear generator(... In order to clarify the mechanism and main influencing factors of the vibration energy coupling transmission with a dual-piston structure,a thermodynamic and dynamic coupling model of the free piston linear generator(FPLG)was established.The system energy conversion,vibration energy coupling transmission,and influencing factors were studied in detail.The coupling transmission paths and the secondary influence mechanism from in-cylinder combustion on vibration energy transmission were obtained.In addition,the influence of the movement characteristics of the dual-piston on the vibration energy transmission was studied,and the typical parameter variation law was obtained,which provides theoretical guidance for the subsequent vibration reduction design of the FPLG. 展开更多
关键词 free piston linear generator(FPLG) coupled motion of dual-piston vibration energy transfer mechanism analysis of influencing factors
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MECHANISM FOR THE INITIATION OF ACRYLONITRILE POLYMERIZATION BY POLYPROPYLENE-BASED POLYAMIDOXIME-THIOUREA COMBINATION
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作者 吴锦远 张广照 杨超雄 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1992年第1期61-69,共9页
Polymerization of acrylonitrile (AN) in aqueous nitric acid initiated by polypropylene-based polyamidoxime (PPAO)-thiourea (TU) combination has been investigated. The overall rate of polymerization (R_p) under the con... Polymerization of acrylonitrile (AN) in aqueous nitric acid initiated by polypropylene-based polyamidoxime (PPAO)-thiourea (TU) combination has been investigated. The overall rate of polymerization (R_p) under the conditions of [TU]/[PPAO]<0.5 molar ratio isThe molecular weights of the polymers were found to be inversely proportional to 3/2-power of nitric acid concentration and 1-power of thiourea concentration. In addition, it is independent with the concentrations of monomer and PPAO, and decreases with increasing temperature.On the basis of these experimental results, a coordination-proton transfer mechanism for the initiation was proposed and discussed. 展开更多
关键词 ACRYLONITRILE Polymerization kinetics Polyamidoxime-thiourea combination Coordination-proton transfer mechanism
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Tiêu Equation Experimentation of Understanding by Energy Transfer Quantum Mechanics
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作者 Huu S. Tieu Martin F. Loeffler 《Natural Science》 CAS 2023年第3期91-102,共12页
Background: The Tiêu equation has a ground roots approach to the process of Quantum Biology and goes deeper through the incorporation of Quantum Mechanics. The process can be measured in plant, animal, and human ... Background: The Tiêu equation has a ground roots approach to the process of Quantum Biology and goes deeper through the incorporation of Quantum Mechanics. The process can be measured in plant, animal, and human usage through a variety of experimental or testing forms. Animal studies were conducted for which, in the first day of the study all the animals consistently gained dramatic weight, even as a toxic substance was introduced as described in the introduction of the paper to harm animal subjects which induced weight loss through toxicity. Tests can be made by incorporating blood report results. Human patients were also observed to show improvement to their health as administration of the substance was introduced to the biological mechanism and plants were initially exposed to the substance to observe results. This is consistent with the Tiêu equation which provides that wave function is created as the introduction of the substance to the biological mechanism which supports Quantum Mechanics. The Tiêu equation demonstrates that Quantum Mechanics moves a particle by temperature producing energy thru the blood-brain barrier for example. Methods: The methods for the Tiêu equation incorporate animal studies to include the substance administered through laboratory standards using Good Laboratory Practices under Title 40 C.F.R. § 158. Human patients were treated with the substance by medical professionals who are experts in their field and have knowledge to the response of patients. Plant applications were acquired for observation and guidance of ongoing experiments of animals’ representative for the biologics mechanism. Results: The animal studies along with patient blood testing results have been an impressive line that has followed the Tiêu equation to consistently show improvement in the introduction of the innovation to biologic mechanisms. The mechanism responds to the substance by producing energy to the mechanism with efficient effect. For plant observations, plant organisms responded, and were seen as showing improvement thru visual observation. 展开更多
关键词 Tiêu Equation Experimentation of Understanding by Energy transfer Quantum Mechanics Golden Sunrise Nutraceutical Huu S. TIȆu Schrödinger Equation Quantum Mechanics Life Is Quantum Biology
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Beyond p-y method:A review of artificial intelligence approaches for predicting lateral capacity of drilled shafts in clayey soils
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作者 M.E.Al-Atroush A.E.Aboelela Ezz El-Din Hemdan 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第9期3812-3840,共29页
In 2023,pivotal advancements in artificial intelligence(AI)have significantly experienced.With that in mind,traditional methodologies,notably the p-y approach,have struggled to accurately model the complex,nonlinear s... In 2023,pivotal advancements in artificial intelligence(AI)have significantly experienced.With that in mind,traditional methodologies,notably the p-y approach,have struggled to accurately model the complex,nonlinear soil-structure interactions of laterally loaded large-diameter drilled shafts.This study undertakes a rigorous evaluation of machine learning(ML)and deep learning(DL)techniques,offering a comprehensive review of their application in addressing this geotechnical challenge.A thorough review and comparative analysis have been carried out to investigate various AI models such as artificial neural networks(ANNs),relevance vector machines(RVMs),and least squares support vector machines(LSSVMs).It was found that despite ML approaches outperforming classic methods in predicting the lateral behavior of piles,their‘black box'nature and reliance only on a data-driven approach made their results showcase statistical robustness rather than clear geotechnical insights,a fact underscored by the mathematical equations derived from these studies.Furthermore,the research identified a gap in the availability of drilled shaft datasets,limiting the extendibility of current findings to large-diameter piles.An extensive dataset,compiled from a series of lateral loading tests on free-head drilled shaft with varying properties and geometries,was introduced to bridge this gap.The paper concluded with a direction for future research,proposes the integration of physics-informed neural networks(PINNs),combining data-driven models with fundamental geotechnical principles to improve both the interpretability and predictive accuracy of AI applications in geotechnical engineering,marking a novel contribution to the field. 展开更多
关键词 Laterally loaded drilled shaft load transfer and failure mechanisms Physics-informed neural networks(PINNs) P-y curves Artificial intelligence(AI) DATASET
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Decomposition of a β-O-4 lignin model compound over solid Cs-substituted polyoxometalates in anhydrous ethanol: acidity or redox property dependence? 被引量:1
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作者 吴学众 焦文千 +4 位作者 李秉正 黎演明 张亚红 王全瑞 唐颐 《Chinese Journal of Catalysis》 CSCD 北大核心 2017年第7期1216-1228,共13页
Production o f aromatics from lignin has attracted much attention. Because of the coexistence of C-O and C-C bonds and their complex combinations in the lignin macromolecular network, a plausible roadmap for de... Production o f aromatics from lignin has attracted much attention. Because of the coexistence of C-O and C-C bonds and their complex combinations in the lignin macromolecular network, a plausible roadmap for developing a lignin catalytic decomposition process could be developed by exploring the transformation mechanisms of various model compounds. Herein, decomposition of a lignin model compound, 2-phenoxyacetophenone (2-PAP), was investigated over several ce-sium-exchanged polyoxometalate (Cs-POM) catalysts. Decomposition of 2-PAP can follow two dif-ferent mechanisms: an active hydrogen transfer mechanism or an oxonium cation mechanism. The mechanism for most reactions depends on the competition between the acidity and redox proper-ties of the catalysts. The catalysts of POMs perform the following functions: promoting active hy-drogen liberated from ethanol and causing formation of and then temporarily stabilizing oxonium cations from 2-PAP. The use of Cs-PMo, which with strong redox ability, enhances hydrogen libera-tion and promotes liberated hydrogen transfer to the reaction intermediates. As a consequence, complete conversion of 2-PAP (〉99%) with excellent selectivities to the desired products (98.6% for phenol and 91.1% for acetophenone) can be achieved. 展开更多
关键词 Lignin model compound β-O-4 ether bond POLYOXOMETALATE Hydrogen transfer mechanism Oxonium cation mechanism Anhydrous ethanol
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Formation of BiOI/g-C_3N_4 nanosheet composites with high visible-light-driven photocatalytic activity 被引量:16
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作者 Hua An Bo Lin +4 位作者 Chao Xue Xiaoqing Yan Yanzhu Dai JinJia Wei Guidong Yang 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第4期654-663,共10页
Constructing binary heterojunctions is an important strategy to improve the photocatalytic performance of graphitic carbon nitride(g‐C3N4).In this paper,a novel g‐C3N4 nanosheet‐based composite was constructed via ... Constructing binary heterojunctions is an important strategy to improve the photocatalytic performance of graphitic carbon nitride(g‐C3N4).In this paper,a novel g‐C3N4 nanosheet‐based composite was constructed via in situ growth of bismuth oxyiodide(BiOI)nanoplates on the surface of g‐C3N4 nanosheets.The crystal phase,microstructure,optical absorption and textural properties of the synthesized photocatalysts were analyzed by X‐ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),ultraviolet‐visible(UV‐vis)diffuse reflectance spectroscopy(DRS),and nitrogen adsorption‐desorption isotherm measurements.The BiOI/g‐C3N4 nanosheet composite showed high activity and recyclability for the photodegradation of the target pollutant rhodamine B(RhB).The conversion of RhB(20 mg L?1)by the photocatalyst was nearly 100%after 50 min under visible‐light irradiation.The high photoactivity of the BiOI/g‐C3N4 nanosheet composite can be attributed to the enhanced visible‐light absorption of the g‐C3N4 nanosheets sensitized by BiOI nanoplates as well as the high charge separation efficiency obtained by the establishment of an internal electric field between the n‐type g‐C3N4 and p‐type BiOI.Based on the characterization and experimental results,a double‐transfer mechanism of the photoinduced electrons in the BiOI/g‐C3N4 nanosheet composite was proposed to explain its activity.This work represents a new strategy to understand and realize the design and synthesis of g‐C3N4 nanosheet‐based heterojunctions that display highly efficient charge separation and transfer. 展开更多
关键词 g‐C3N4 BiOI NANOSHEET PHOTODEGRADATION Double‐transfer mechanism Visible light
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Displacement and deformation analysis for uplift piles 被引量:7
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作者 杨小礼 邹金锋 《Journal of Central South University of Technology》 EI 2008年第6期906-910,共5页
On the assumptions that the shear resistance increases linearly with increasing shear displacement between the uplift pile and surrounding soil, that the axis force is distributed as parabola along the pile length, th... On the assumptions that the shear resistance increases linearly with increasing shear displacement between the uplift pile and surrounding soil, that the axis force is distributed as parabola along the pile length, that elastic distortion occurs when the pile is loaded, that the displacement of pile is in accord with that of the soil, and that the uplift pile failure is regarded as the soil failure, a rational calculation method was proposed for calculating the deformation, ultimate displacement and shear resistance of piles. The distributions of frictional resistance and the shear displacement along the pile length were obtained with the method. The comparisons were made between the measurement results and the present results. The present theoretical results agree well with the measurement results, with the average difference being less than 12% before failure. The comparisons show that the proposed method is reasonable for uplift design and engineering construction of piles. 展开更多
关键词 uplift pile load transfer mechanism DISPLACEMENT DEFORMATION
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Characterization of Low Pressure RF Plasma Heating 被引量:2
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作者 Wenxia Pan Fanxiu Lu Toyonobu Yoshida (Materials Science and Engineering School, University of Science and Technology Beijing, Beijing 100083, China)(Department of Metallurgy, The University of Tokyo, Tokyo 113, Japan) 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 1998年第1期31-35,共5页
Compacts of a-Al2O3 and Mo powder were heated in radio-frequency (RF) induced low pressure N2, H2,Ar, and their mixture plasma. An optical pyrometer, a radiation pyrometer, and a system called Accufiber Model310 we... Compacts of a-Al2O3 and Mo powder were heated in radio-frequency (RF) induced low pressure N2, H2,Ar, and their mixture plasma. An optical pyrometer, a radiation pyrometer, and a system called Accufiber Model310 were used to measure the temperature of compacts heated in the plasma. The results indicate that there are different heat transfer mechanisms from plasma to specimens of different physical properties. The Ar plasma showed thehighest heating ability among N2, H2, and Ar plasma for Al2O3 specimens, whereas the H2 plasma could heat Mospecimens to a higher temperature than the Ar plasma did, even under the same generating conditions. 展开更多
关键词 plasma heating temperature measurement heat transfer mechanism
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