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Phase composition,conductivity,and sensor properties of cerium-doped indium oxide
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作者 M.I.Ikim G.N.Gerasimov +2 位作者 V.F.Gromov O.J.Ilegbusi L.I.Trakhtenberg 《Nano Materials Science》 EI CAS CSCD 2024年第2期193-200,共8页
The hydrothermal synthesis of In_(2)O_(3)and CeO_(2)–In_(2)O_(3)is investigated as well as the properties of sensor layers based on these compounds.During the synthesis of In_(2)O_(3),intermediate products In(OH)_(3)... The hydrothermal synthesis of In_(2)O_(3)and CeO_(2)–In_(2)O_(3)is investigated as well as the properties of sensor layers based on these compounds.During the synthesis of In_(2)O_(3),intermediate products In(OH)_(3)and InOOH are formed,which are the precursors of stable cubic(c-In_(2)O_(3))and metastable rhombohedral(rh-In_(2)O_(3))phases,respectively.A transition from c-In_(2)O_(3)to rh-In_(2)O_(3)is observed with the addition of CeO_(2).The introduction of cerium into rh-In_(2)O_(3)results in a decrease in the sensor response to hydrogen,while it increases in composites based on c-In_(2)O_(3).The data on the sensor activity of the composites correlate with XPS results in which CeO_(2)causes a decrease in the concentrations of chemisorbed oxygen and oxygen vacancies in rh-In_(2)O_(3).The reverse situation is observed in composites based on c-In_(2)O_(3).Compared to In_(2)O_(3)and CeO_(2)–In_(2)O_(3)obtained by other methods,the synthesized composites demonstrate maximum response to H_(2)at low temperatures by 70–100℃,and have short response time(0.2–0.5 s),short recovery time(6–7 s),and long-term stability.A model is proposed for the dependence of sensitivity on the direction of electron transfer between In_(2)O_(3)and CeO_(2). 展开更多
关键词 Cerium oxide Indium oxide NANOCOMPOSITE Hydrothermal method Cubic phase Rhombohedral phase Sensor response CONDUCTIVITY HYDROGEN Response/recovery time
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Numerical Simulation Study of Oil-Water Emulsion Separation in an Ultrasonic Field:Effect of Coupling between Acoustic and Flow Field Parameters
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作者 Wang Heping Lin Yinchao +2 位作者 Li Yanggui Zhang Xiaohang Wu Yi 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS CSCD 2024年第1期116-125,共10页
In this study,the separation and coalescence of oil-in-water emulsions are explored in an ultrasonic field using the lattice Boltzmann method.By simulating the propagation of ultrasonic waves,this study focuses on exa... In this study,the separation and coalescence of oil-in-water emulsions are explored in an ultrasonic field using the lattice Boltzmann method.By simulating the propagation of ultrasonic waves,this study focuses on examining the effects of acoustic wave frequency,the ratio of oil to water components,and the aspect ratio of the boundary on the emulsification and separation processes of oil-water mixtures.The following conclusions are drawn.①Frequency affects the speed of oil droplet separation,leading to an increase in droplet size over time.Larger droplets are found near the source,while smaller droplets are distributed throughout the wave web.②As the boundary aspect ratio increases,the emulsification efficiency of the droplets weakens,and the system takes longer to stabilize.③Emulsions with a higher component of oil can better resist acoustic waves.④At the same acoustic frequency,longer wavelength ultrasonic fields promote the formation of uniformly distributed,smaller oil droplets,which is beneficial to the storage of emulsions.These numerical simulation results offer insights for optimizing conditions for oil-in-water separation and serve as a numerical reference for the study of oil-in-water emulsion separation in ultrasonic environments. 展开更多
关键词 lattice Boltzmann method phase separation ultrasound field
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Phase behavior and percolation in an equilibrium system of symmetrically interacting Janus disks on the triangular lattice
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作者 张希贤 胡皓 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第8期216-225,共10页
A Janus particle has two distinct areas on its surface.Denoting the two areas as P(patch)and N(nonpatch),when two particles come close to each other,the strength of the PP interaction is usually different from that of... A Janus particle has two distinct areas on its surface.Denoting the two areas as P(patch)and N(nonpatch),when two particles come close to each other,the strength of the PP interaction is usually different from that of the NN interaction.Recently the interplay between a rotational-symmetry-breaking continuous phase transition and percolation has been explored for an equilibrium system of asymmetrically interacting(i.e.,attractive PP interaction,zero NN and PN interactions)Janus disks on the triangular lattice.By Monte Carlo simulation and finite-size scaling analysis,in this work we study an equilibrium system of symmetrically interacting(i.e.,attractive PP and NN interactions with the same strength,zero PN interaction)Janus disks on the same lattice.By definition,the phase diagram in the T-θplane is symmetric for systems with patch sizesθbelow and above 90°.We determine the phase diagram and compare it with that of the asymmetric system.Similar to the latter system,for 60°<θ<90°,a rotational-symmetry-breaking continuous phase transition and an anisotropic percolation transition are found in the symmetric system,though the transition points in the two systems are quite different.Phase crossover curves are found to be different,e.g.,a continuous varying crossover line extends betweenθ=0°and 90°for the symmetric model;and in the range 0°<θ≤30°,along the crossover lines of the two models,the trends of 1/T vs.θare opposite in the two systems.We understand the latter by analytically solving the models with two particles in 0°<θ≤30°.These results are helpful for understanding close-packed systems of Janus disks with more complex interactions. 展开更多
关键词 Janus particles phase transitions PERCOLATION Monte Carlo methods
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Enhancement of MAD/MIR phasing at low resolution and a new procedure for automatic phase extension
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作者 韩普 古元新 +1 位作者 丁玮 范海福 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第7期389-395,共7页
To achieve de novo protein structure determination of challenging cases, multi-wavelength anomalous diffraction(MAD) and multiple isomorphous replacement(MIR) phasing can be powerful tools to obtain low-resolution ini... To achieve de novo protein structure determination of challenging cases, multi-wavelength anomalous diffraction(MAD) and multiple isomorphous replacement(MIR) phasing can be powerful tools to obtain low-resolution initial phases from heavy-atom derivative datasets, then phase extension is needed against high-resolution data to obtain accurate structures.In this context, we propose a direct-methods procedure here that could improve the initial low-resolution MAD/MIR phase quality.And accordingly, an automated process for extending initial phases to high resolution is also described.These two procedures are both implanted in the newly released IPCAS pipeline.Three cases are used to perform the test, including one set of 4.17 ? MAD data from a membrane protein and two sets of MAD/MIR data with derivatives truncated down to 6.80 ? and 6.90 ?, respectively.All the results have shown that the initial phases generated from the direct-methods procedure are better than that from the conventional MAD/MIR methods.The automated phase extensions for the latter two cases starting from 6.80 ? to 3.00 ? and 6.90 ? to 2.80 ? are proved to be successful, leading to complete models.This may provide convenient and reliable tools for phase improvement and phase extension in difficult low-resolution tasks. 展开更多
关键词 direct methods MULTI-WAVELENGTH anomalous diffraction(MAD)/multiple isomorphous replacement(MIR) PHASING phase EXtenSION low-resolution
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Data-driven optimization study of the multi-relaxation-time lattice Boltzmann method for solid-liquid phase change 被引量:1
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作者 Yanlin REN Zhaomiao LIU +1 位作者 Zixiao KANG Yan PANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第1期159-172,共14页
Sharp phase interfaces and accurate temperature distributions are important criteria in the simulation of solid-liquid phase changes.The multi-relaxation-time lattice Boltzmann method(MRT-LBM)shows great numerical per... Sharp phase interfaces and accurate temperature distributions are important criteria in the simulation of solid-liquid phase changes.The multi-relaxation-time lattice Boltzmann method(MRT-LBM)shows great numerical performance during simulation;however,the value method of the relaxation parameters needs to be specified.Therefore,in this study,a random forest(RF)model is used to discriminate the importance of different relaxation parameters to the convergence,and a support vector machine(SVM)is used to explore the decision boundary of the convergent samples in each dimensional model.The results show that the convergence of the samples is consistent with the sign of the decision number,and two types of the numerical deviations appear,i.e.,the phase mushy zone and the non-physical heat transfer.The relaxation parameters chosen on the decision boundary can further suppress the numerical bias and improve numerical accuracy. 展开更多
关键词 solid-liquid phase change lattice Boltzmann method(LBM) relaxation parameter random forest(RF) support vector machine(SVM)
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RESEARCH ON METHOD TO CALCULATE VELOCITIES OF SOLID PHASE AND LIQUID PHASE IN DEBRIS FLOW 被引量:4
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作者 陈洪凯 唐红梅 陈野鹰 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2006年第3期399-408,共10页
Velocities of solid phase and liquid phase in debris flow are one key problem to research on impact and abrasion mechanism of banks and control structures under action of debris flow. Debris flow was simplified as two... Velocities of solid phase and liquid phase in debris flow are one key problem to research on impact and abrasion mechanism of banks and control structures under action of debris flow. Debris flow was simplified as two-phase liquid composed of solid phase with the same diameter particles and liquid phase with the same mechanical features. Assume debris flow was one-dimension two-phase liquid moving to one direction, then general equations of velocities of solid phase and liquid phase were founded in two-phase theory. Methods to calculate average pressures, volume forces and surface forces of debris flow control volume were established. Specially, surface forces were ascertained using Bingham's rheology equation of liquid phase and Bagnold's testing results about interaction between particles of solid phase. Proportional coefficient of velocities between liquid phase and solid phase was put forward, meanwhile, divergent coefficient between theoretical velocity and real velocity of solid phase was provided too. To state succinctly before, method to calculate velocities of solid phase and liquid phase was obtained through solution to general equations. The method is suitable for both viscous debris flow and thin debris flow. Additionally, velocities every phase can be identified through analyzing deposits in-situ after occurring of debris flow. It is obvious from engineering case the result in the method is consistent to that in real-time field observation. 展开更多
关键词 debris flow two-phase fluid velocities of solid phase and liquid phase calculation method VERIFICATION
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Extraction of pipeline defect feature based on variational mode and optimal singular value decomposition
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作者 Min Zhang Yan-Bao Guo +4 位作者 Zheng Zhang Ren-Bi He De-Guo Wang Jin-Zhong Chen Tie Yin 《Petroleum Science》 SCIE EI CAS CSCD 2023年第2期1200-1216,共17页
Because the magnetic signal information of pipeline defects obtained by magnetic flux leakage detection contains interference signals, it is difficult to accurately extract the features. Therefore, a novel pipeline de... Because the magnetic signal information of pipeline defects obtained by magnetic flux leakage detection contains interference signals, it is difficult to accurately extract the features. Therefore, a novel pipeline defect feature extraction method based on VMD-OSVD (variational modal decomposition - optimal singular value decomposition) is proposed to promote the signal to noise ratio (SNR) and reduce aliasing in the frequency domain. By using the VMD method, the sampled magnetic signal is decomposed, and the optimal variational mode is selected according to the rate of relative change (VMK) of Shannon entropy (SE) to reconstruct the signal. After that, SVD algorithm is used to filter the reconstructed signal again, in which the H-matrix is optimized with the phase-space matrix to enhance SNR and decrease the frequency domain aliasing. The results show that the method has excellent denoising ability for defect magnetic signals, and SNR is increased by 21.01%, 24.04%, 0.96%, 32.14%, and 20.91%, respectively. The improved method has the best denoising effect on transverse mechanical scratches, but a poor denoising effect on spiral welding position. In the frequency domain, the characteristics of different defects are varied, and their corresponding frequency responses are spiral weld corrosion > transverse mechanical cracking > girth weld > deep hole > normal pipe. The high-frequency band is the spiral weld corrosion with f1 = 153.37 Hz. The low-frequency band is normal with f2 = 1 Hz. In general, the VMD-OSVD method is able to improve the SNR of the signal and characterize different pipe defects. And it has a certain guiding significance to the application of pipeline inspection in the field of safety in the future. 展开更多
关键词 VMD method VMK SVD algorithm phase space matrix Signal characteristics Pipeline defect Reconstruct
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A framework for identifying the onset of landslide acceleration based on the exponential moving average(EMA)
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作者 WANG Jia-zhu JU Neng-pan +2 位作者 TIE Yong-bo BAI Yong-jian GE Hua 《Journal of Mountain Science》 SCIE CSCD 2023年第6期1639-1649,共11页
Predicting the failure time of a landslide is considered as challenging work in the field of landslide research,and inverse velocity is proved to be an effective and convenient method.The onset of acceleration(OOA)has... Predicting the failure time of a landslide is considered as challenging work in the field of landslide research,and inverse velocity is proved to be an effective and convenient method.The onset of acceleration(OOA)has a crucial effect on the prediction failure time from the inverse velocity method.However,a simple method to identify OOA points is lacked,and most of the identifications rely on expert experience.Therefore,this study presents an application of a simple framework developed to identify the OOA by analyzing monitoring velocity data in three steps,including selection of the absolute value of velocity,reliable area identification and OOA identification.A new parameter based on exponential moving average(EMA)is developed to identify the landslide OOA.The framework is applied to three historical case studies to test its practicability and effectiveness.The forecasting results show a good correspondence between the accuracy rate and the coefficient of determination(R2).The predicted failure time according to the linear extrapolation starting from the identified OOA points is acceptable with a high R2 and high accuracy. 展开更多
关键词 Landslides failure time ACCELERATION Inverse velocity method Monitoring Tertiary creep phase
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Appraisal of Engineering Phases of a Mineral Asset: From Exploration to Mine Approval
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作者 Edmundo Tulcanaza 《Journal of Minerals and Materials Characterization and Engineering》 CAS 2023年第3期69-79,共11页
It is well known that the most common methodology for evaluating a mineral asset is the NPV. Most of the mining companies employ this technique for evaluating the expected economic benefits provided by the exploration... It is well known that the most common methodology for evaluating a mineral asset is the NPV. Most of the mining companies employ this technique for evaluating the expected economic benefits provided by the exploration and exploitation of a mineral deposit. However, companies also wish to know how their assets are creating value through the several exploration and development phases. The purpose being to assess the progressive value of the mineral asset in agreement with the information and data cumulated through the different steps from exploration to project approval. This paper establishes the value of a copper mineral deposit through their successive phases from exploration to feasibility and approval using the options’ binomial nodes framework. Results are applied to two copper negotiations for method validation. 展开更多
关键词 Mine Value Exploration phases Binomial Nodes Copper Deposits Method Validation
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Analysis on high-temperature oxidation and growth stress of iron-based alloy using phase field method 被引量:1
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作者 杨帆 刘彬 方岱宁 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2011年第6期757-764,共8页
High-temperature oxidation is an important property to evaluate thermal protection materials. However, since oxidation is a complex process involving microstructure evolution, its quantitative analysis has always been... High-temperature oxidation is an important property to evaluate thermal protection materials. However, since oxidation is a complex process involving microstructure evolution, its quantitative analysis has always been a challenge. In this work, a phase field method (PFM) based on the thermodynamics theory is developed to simulate the oxidation behavior and oxidation induced growth stress. It involves microstructure evolution and solves the problem of quantitatively computational analysis for the oxidation behavior and growth stress. Employing this method, the diffusion process, oxidation performance, and stress evolution axe predicted for Fe-Cr-A1-Y alloys. The numerical results agree well with the experimental data. The linear relationship between the maximum growth stress and the environment oxygen concentration is found. PFM provides a powerful tool to investigate high-temperature oxidation in complex environments. 展开更多
关键词 high-temperature OXIDATION phase field method growth stress
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Controllable Synthesis of Mixed-Phase TiO_2 with Small Anatase and Rutile Particle and Its Enhanced Photocatalytic Activity 被引量:1
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作者 Bai Yu Li Kuan +1 位作者 Chen Xuebing Zhang Jing 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2018年第1期37-43,共7页
Mixed-phase TiO_2 photocatalysts with small particle size of anatase and rutile(~5 nm) have been successfully synthesized using hydrothermal method. The effects of curing temperature and curing time before the hydroth... Mixed-phase TiO_2 photocatalysts with small particle size of anatase and rutile(~5 nm) have been successfully synthesized using hydrothermal method. The effects of curing temperature and curing time before the hydrothermal treatment on the crystalline phase, the phase composition, and the particle size of TiO_2 were investigated by the X-ray diffraction spectroscopy(XRD) and the transmission electron microscopy(TEM), respectively. It was found that the anatase and rutile phase contents in the TiO_2 particles were successfully controlled by simply adjusting the curing temperature and the curing time. More importantly, the particle size of both anatase and rutile is small in the mixed-phase TiO_2 particles. The photocatalytic activity of TiO_2 was evaluated by the degradation of Rhodamine B(Rh B) in aqueous solution. The Ti O2 with phase junction formed by anatase and rutile exhibited higher separation rate between the photo-induced electrons and holes, which was confirmed by the surface photovoltage(SPV) spectra, and at the same time exhibited the higher photocatalytic degradation on Rh B than pure anatase-phase TiO_2. Moreover, it was found that TiO_2 with 83% of anatase and 17% of rutile showed a highest photocatalytic activity among the mixed-phase TiO_2 samples. 展开更多
关键词 TiO2 phase juction HYDROTHERMAL method photocatalytic degradation
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A Forecasting Model of Vector Similarity in Phase Space for Flood and Drought over the Huanghe-Huaihe-Haihe Plain in China 被引量:1
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作者 周家斌 王允宽 +1 位作者 杨桂英 吴津生 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1994年第2期224-229,共6页
To represent well the characteristics of temporal and spatial distributions, chart of 3-dekad moving total precipitation is proposed in this paper first. Then this kind of chart is expanded in terms of Chebyshev polyn... To represent well the characteristics of temporal and spatial distributions, chart of 3-dekad moving total precipitation is proposed in this paper first. Then this kind of chart is expanded in terms of Chebyshev polynomial at irregular grids, and the quantitative representation of precipitation is got. Finally the Chebyshev coefficients are forecasted by using the forecasting method of vector similarity in phase space proposed by Zhou (1992). Using above mentioned procedures temporal and spatial distributions of precipitation over the Huanghe-- Huaihe-- H aihe Plain in China are forecasted. 展开更多
关键词 3-dekad moving total precipitation Chebyshev expansion Forecasting method phase space
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HPLC Profiling for Quality Control of Secondary Metabolites of Aqueous and Hydroethanolic Extract of Gardenia aqualla Stapf &Hutch
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作者 Claude Bérenger Ngantchouko Ngalemo Jean Kisito Kouame +5 位作者 Gisele Laurel Tchiengang Tchoua Blondin Gatien Tsawo Patrick Yamen Mbopi Théophille Dimo Christophe N’cho Amin François Nicaise Bony 《American Journal of Analytical Chemistry》 CAS 2023年第1期1-11,共11页
WHO strategy on traditional medicine is based on security and quality of phytomedicine. Commonly adulterated affecting mostly metabolic and sexual dysfunction drugs. Control quality of those phytomedicines requires de... WHO strategy on traditional medicine is based on security and quality of phytomedicine. Commonly adulterated affecting mostly metabolic and sexual dysfunction drugs. Control quality of those phytomedicines requires development of strategy and techniques applicable to them. Among the techniques, Reverse Phase Liquid Chromatography is the most used and has been developed in these studies to assess a protocol to characterize Gardenia aqualla leaves extract. The method consists in determining chromatographic conditions using organic and pH gradient models based on water and acetonitrile combined with pH modifiers made up of formic acid (AF) and ammonium hydroxide (NH<sub>3</sub>). Results show that extracts contain mainly acidic compounds quickly eluted by NH<sub>3</sub> and more retained by AF. Optimal pH range for separation is 3 - 7 corresponding to 1.59 mM of NH<sub>3</sub> and 6.55 mM of AF. In these conditions, elution of many polar compounds could be effective using a C18 based-deactivated column in a short period of time. 展开更多
关键词 Gardenia aqualla Extracts Quality Control Method Development Reverse phase Liquid Chromatography
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PHASE EXTENSION AND STRUCTURE ANALYSIS BY THE MAXIMUM ENTROPY METHOD 被引量:1
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作者 G.B.Hu and Q.B.Yang (Department of Physics, Xiangtan University, Xiangtan 411105, China)(Beijing Laboratory of Electron Microscopy, Center for Condensed Matter Physics, The Chinese Academy of Sciences, P. O. Box 2724, Beijing 100080, China) 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1998年第4期241-254,共14页
Excellent results are obtained in structure analysis with jew phases of structure factors by the maximum-entropy method (MEM) for CaGaN PbCO3 and ReBe22 single crystals. The computation time and memory space are minim... Excellent results are obtained in structure analysis with jew phases of structure factors by the maximum-entropy method (MEM) for CaGaN PbCO3 and ReBe22 single crystals. The computation time and memory space are minimized by symmetry operations so that structure analysis by the MEM can be carried out with a personal computer. 展开更多
关键词 maximum entropy method structure analysis phase extension symmetry
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A modified damage and fracture phase field model considering heterogeneity for rock‐like materials
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作者 Xuxin Chen Zhe Qin 《Deep Underground Science and Engineering》 2023年第3期286-294,共9页
Damage and fracture are the most extensive failure modes of rock materials,which may easily induce disaster and instability of engineering structures.This study developed a nonlocal damage fracture phase field model f... Damage and fracture are the most extensive failure modes of rock materials,which may easily induce disaster and instability of engineering structures.This study developed a nonlocal damage fracture phase field model for rocks considering the heterogeneity of rocks.The modified phase field model introduced the heterogeneity of fracture parameters and modified the governing equations.Meanwhile,the free energy was constructed by the elastic strain energy sphere‐bias decomposition and the plastic strain energy.As for the numerical implementation,the three layers finite elements method structure was used in the frame of the finite element method.The ability of the modified phase field model has been illustrated by reproducing the experiment results of rock samples with pre‐existing cracks under compression. 展开更多
关键词 crack propagation HETEROGENEITY numerical implementation phase field method rock‐like materials
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Transforming Molecules into Medicines: Role of CDMOS in Phase-Appropriate Technology Transfers in Advancing Pharmaceutical Innovation
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作者 Kishore Kumar Hotha 《Advances in Chemical Engineering and Science》 2023年第3期203-223,共21页
CDMOs are emerging as critical drivers of innovation within the pharmaceutical and biotech industries. As the pharmaceutical industry continues to evolve, we can expect to see CDMOs play an increasingly important role... CDMOs are emerging as critical drivers of innovation within the pharmaceutical and biotech industries. As the pharmaceutical industry continues to evolve, we can expect to see CDMOs play an increasingly important role in drug development and manufacturing. Many companies within these sectors are now leveraging the expertise of CDMOs through technology transfers to foster innovation and enhance the development of new drug products. In the extensive field of drug development, technology transfer plays a crucial role at multiple stages, ranging from preclinical phases to commercialization. By working closely with drug developers, CDMOs can ensure that technologies are transferred seamlessly between phases of drug development, allowing for a more efficient and cost-effective development process. CDMOs also bring a wealth of experience in various areas of drug development, including process development, analytical testing, quality control, and manufacturing. This expertise, combined with a focus on innovation, can help drug developers to overcome technical challenges and optimize their drug development programs. CDMOs can provide drug developers with various manufacturing capabilities, from small-scale clinical trials to large-scale commercial production. This flexibility allows drug developers to focus on their core competencies while relying on CDMOs to provide the necessary infrastructure and support for drug manufacturing. The critical role of CDMOs in advancing pharmaceutical innovation in phase-appropriate technology transfer where there will be a lot of effort and patience with strong technical expertise is required. This article explores the various types of Technology transfer from preclinical to commercial stages and successful strategies to foster innovation. 展开更多
关键词 Technology Transfer CDMO INNOVATION PRECLINICAL GMP phase Appropriate Method Development phase-1 Commercial Manufacturing Continuous Improvement Lifecycle Management
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The efficiency and accuracy of probability diagram, spatial statistic and fractal methods in the identification of shear zone gold mineralization: a case study of the Saqqez gold ore district,NW Iran 被引量:1
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作者 Mirmahdi Seyedrahimi-Niaraq Amin Hekmatnejad 《Acta Geochimica》 EI CAS CSCD 2021年第1期78-88,共11页
In this study,geochemical anomaly separation was carried out with methods based on the distribution model,which includes probability diagram(MPD),fractal(concentration-area technique),and U-statistic methods.The main ... In this study,geochemical anomaly separation was carried out with methods based on the distribution model,which includes probability diagram(MPD),fractal(concentration-area technique),and U-statistic methods.The main objective is to evaluate the efficiency and accuracy of the methods in separation of anomalies on the shear zone gold mineralization.For this purpose,samples were taken from the secondary lithogeochemical environment(stream sediment samples)on the gold mineralization in Saqqez,NW of Iran.Interpretation of the histograms and diagrams showed that the MPD is capable of identifying two phases of mineralization.The fractal method could separate only one phase of change based on the fractal dimension with high concentration areas of the Au element.The spatial analysis showed two mixed subpopulations after U=0 and another subpopulation with very high U values.The MPD analysis followed spatial analysis,which shows the detail of the variations.Six mineralized zones detected from local geochemical exploration results were used for validating the methods mentioned above.The MPD method was able to identify the anomalous areas higher than 90%,whereas the two other methods identified 60%(maximum)of the anomalous areas.The raw data without any estimation for the concentration was used by the MPD method using aminimum of calculations to determine the threshold values.Therefore,the MPD method is more robust than the other methods.The spatial analysis identified the detail soft hegeological and mineralization events that were affected in the study area.MPD is recommended as the best,and the spatial U-analysis is the next reliable method to be used.The fractal method could show more detail of the events and variations in the area with asymmetrical grid net and a higher density of sampling or at the detailed exploration stage. 展开更多
关键词 Shear zone gold deposit Modeling of probability diagram method Concentration-area fractal method U-spatial statistics method phases of efficiency and accuracy mineralization
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An improvement to the simulation of phase-change heat-transfer during soil freezing and thawing 被引量:6
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作者 YANG Tao ZHENG Mao-yu 《Mining Science and Technology》 EI CAS 2009年第2期262-268,共7页
A new variable time step method,which is called the backwards calculating time step method,is presented in this paper.It allows numerical simulation of soil freezing and thawing while avoiding "phase change missi... A new variable time step method,which is called the backwards calculating time step method,is presented in this paper.It allows numerical simulation of soil freezing and thawing while avoiding "phase change missing and overflowing".A sensitive heat capacity model is introduced through which the calculation errors are analyzed.Then the equation using the self-adjusted time step is presented and solved using finite differences.Through this equation,the time needed for a space cell to reach the phase change point temperature is calculated.Using this time allows the time step to be adjusted so that errors caused by "phase change missing and overflowing" are successfully eliminated.Above all,the obvious features of this method are an accelerated rate for adjusting the time step and simplifing the computations.An actual example proves that this method can accurately calculate the temperature fields during soil freezing and thawing.It is an improvement over traditional methods and can be widely used on complicated multi-dimensional phase change problems. 展开更多
关键词 相变传热 土壤冻融 数值模拟 时间步长 计算错误 传统方法 温度场 热容量
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Sm^(3+)掺杂LaOF荧光粉的制备及光学性能
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作者 贾宇盟 史忠祥 +1 位作者 王晶 李翔 《材料导报》 EI CAS CSCD 北大核心 2024年第3期13-19,共7页
以LaOF晶体为基质,利用水热辅助固相法制备出一系列Sm^(3+)掺杂LaOF荧光粉。采用XRD、TEM、荧光光谱仪等测试手段对所制得的样品的相结构、微观形貌及光学性能进行表征。结果表明,LaOF在不同煅烧温度下会产生四方相和斜方六面体两种不... 以LaOF晶体为基质,利用水热辅助固相法制备出一系列Sm^(3+)掺杂LaOF荧光粉。采用XRD、TEM、荧光光谱仪等测试手段对所制得的样品的相结构、微观形貌及光学性能进行表征。结果表明,LaOF在不同煅烧温度下会产生四方相和斜方六面体两种不同晶相。此外,由于受跃迁概率和局域对称性的影响,Sm^(3+)掺杂四方相LaOF发光强度更大,其各浓度样品在405 nm光激发下,于567 nm、605 nm、651 nm和710 nm等处均出现了Sm^(3+)的特征发射峰,并且随着Sm^(3+)掺杂量的增加,其发光强度呈现先增大后减小的趋势,且当Sm^(3+)掺杂量为3.0%(摩尔分数,下同)时,La_(1-x)Sm_(x)OF样品发光强度达最大值。此外,所得样品的色纯度极高,其多个激发峰均位于商用近紫外和蓝光LED芯片的发射波长附近,可实现多种波长激发下的可见橙光发射。 展开更多
关键词 水热辅助固相法 稀土元素 钐掺杂 光学性能
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A feedback control method for phase signal demodulation in fber-optic hydrophones
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作者 Zhiqiang LIU Lei XIA +3 位作者 Qiangfeng LYU Bin WU Ronghua HUAN Zhilong HUANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第3期515-528,共14页
In the realm of acoustic signal detection,the identification of weak signals,particularly in the presence of negative signal-to-noise ratios,poses a significant challenge.This challenge is further heightened when sign... In the realm of acoustic signal detection,the identification of weak signals,particularly in the presence of negative signal-to-noise ratios,poses a significant challenge.This challenge is further heightened when signals are acquired through fiber-optic hydrophones,as these signals often lack physical significance and resist clear systematic modeling.Conventional processing methods,e.g.,low-pass filter(LPF),require a thorough understanding of the effective signal bandwidth for noise reduction,and may introduce undesirable time lags.This paper introduces an innovative feedback control method with dual Kalman filters for the demodulation of phase signals with noises in fiber-optic hydrophones.A mathematical model of the closed-loop system is established to guide the design of the feedback control,aiming to achieve a balance with the input phase signal.The dual Kalman filters are instrumental in mitigating the effects of signal noise,observation noise,and control execution noise,thereby enabling precise estimation for the input phase signals.The effectiveness of this feedback control method is demonstrated through examples,showcasing the restoration of low-noise signals,negative signal-to-noise ratio signals,and multi-frequency signals.This research contributes to the technical advancement of high-performance devices,including fiber-optic hydrophones and phase-locked amplifiers. 展开更多
关键词 feedback control method fiber-optic hydrophone acoustic signal detection phase signal
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