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3-D tunnel seismic advance prediction method with wide illumination and high-precision

Journal of Earth Science 2021年

作者： Peng Guan cui–fa shao Yu–Yong Jiao Guo–Hua Zhang Jun–Peng Zou Fei Tan faculty of Engineering， China University of Geosciences

Tunnel seismic advance prediction can effectively reduce the construction risk during tunnel excavation. Compared with the 2-D method， the 3-D method is more conducive to describing the spatial characteristics of the geological body by adding the seismic data in the vertical direction. However， some drawbacks still need improvement in the current 3-D tunnel seismic prediction method. 1) The geometry is complex， which is destructiveness， high cost， and time-consuming， and will delay the tunnel construction schedule. 2) Illumination of the anomalous body is insufficient， and the precision of migration imaging is low. 3) Shot points are far away from the tunnel face，the energy loss at the shot points is more serious. 4) The received signals at the tunnel wall have the surface wave with strong energy when the shot points are placed on the tunnel wall. 5) The geometry is notlinear， so the directional filtering method cannot be used to extract the reflection wave. To overcome the drawbacks of the current prediction method， this paper proposes a new 3-D symmetrical tunnel seismic prediction method. Six geophones are installed on the tunnel wall， two on the left side， two on the right side， and two on the top side. Twenty-four shot points are placed on the tunnel face and near both sides of the tunnel wall， twelve shot points on the left side and twelve shot points on the right side. The shot points will move along with the forward excavation of the tunnel. The wavefield analysis， illumination statistics， and 3-D reverse time migration imaging are used to evaluate the proposed method. The result of modeled data indicates that the proposed 3-D geometry has some advantages as following: 1) The geometry is simple and the geophone installation time is short. 2) It has high illumination energy， wide illumination range， and can improve the prediction distance and imaging accuracy. 3) The proposed 3-D method can better estimate the velocity of surrounding rock and is more conduciv

关键词： Geometry Illumination Migration Tunnel seismic advance prediction

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3-D tunnel seismic advance prediction method with wide illumination and high-precision

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Journal of Earth Science 2021年

作者： Peng Guan cui–fa shao Yu–Yong Jiao Guo–Hua Zhang Jun–Peng Zou Fei Tan faculty of Engineering， China University of Geosciences

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Multi-objective optimization of cooling air distribution of grate cooler with different inlet temperatures by using genetic algorithm

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Science China(Technological Sciences) 2017年第3期60卷 345-354页

作者： shao Wei cui Zheng CHENG Lin Institute of Thermal Science and Technology Shandong University Jinan 250061 China

The paper discussed a multi-objective optimization model of the cooling air distribution of a grate cooler according to the analogy

关键词： cooling air distribution grate cooler multi-objective genetic algorithm entropy generation

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Recent advances in metal-organic frameworks for catalytic CO_(2) hydrogenation to diverse products

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Nano Research 2022年第12期15卷 10110-10133页

作者： Shengxian shao Chengqian cui Zhiyong Tang Guodong Li CAS Key Laboratory of Nanosystem and Hierarchical fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing100190China School of Nanoscience and Technology University of Chinese Academy of SciencesBeijing100049China

Selective hydrogenation of CO_(2) to high value-added chemicals,not only gives an effective way to reduce the concentration of CO_(2),but also provides the precursors to advance the industrial manufacturing of chemicals and *** the well-defined reticular frameworks and flexible modifiability,metal-organic frameworks(MOFs)can be the ideal platform to construct the enabled catalysts for CO_(2) hydrogenation,because they have shown the great potential for the enhancement of catalytic activity,the precise control of selectivity,and the excellent *** this review,we systematically summarize the recent advances in MOFs based catalysts for CO_(2) hydrogenation towards diverse ***,synthesis strategies for different kinds of MOFs based catalysts are ***,selective hydrogenation of CO_(2) towards CO and methane is discussed over various metal nanoparticles/MOFs ***,heterogenization and isolation of molecular catalysts by MOFs are elaborated for producing formic ***,selective hydrogenation of CO_(2) toward methanol is discussed in terms of interface structures of Cu,Zn,and metal nodes of MOFs,the synergy between auxiliary sites and noble metal,and tandem catalytic systems of molecular catalysts and Lewis acid ***,the integration of multiple metal sites,promoters,and cocatalysts into MOFs is described for the selective hydrogenation of CO_(2) to C2+*** those,the key issue about the stability of MOFs based catalysts for CO_(2) hydrogenation reaction is ***,the summary and perspective about MOFs based catalysts for selective CO_(2) hydrogenation and mechanism research are proposed.

关键词： selective CO_(2)hydrogenation metal-organic frameworks(MOFs) noble metal nonnoble metal diverse products mechanism

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Snapshot boosting: a fast ensemble framework for deep neural networks

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Science China(Information Sciences) 2020年第1期63卷 77-88页

作者： Wentao ZHANG Jiawei JIANG Yingxia shao Bin cui Center for Data Science Peking University National Engineering Laboratory for Big Data Analysis and Applications Department of Computer Science Beijing Key Lab of Intelligent Telecommunications Software and Multimedia School of Computer ScienceBeijing University of Posts and Telecommunications Key Lab of High Confidence Software Technologies Department of Computer SciencePeking University

Boosting has been proven to be effective in improving the generalization of machine learning models in many fields. It is capable of getting high-diversity base learners and getting an accurate ensemble model by combining a sufficient number of weak learners. However, it is rarely used in deep learning due to the high training budget of the neural network. Another method named snapshot ensemble can significantly reduce the training budget, but it is hard to balance the tradeoff between training costs and diversity. Inspired by the ideas of snapshot ensemble and boosting, we propose a method named snapshot boosting. A series of operations are performed to get many base models with high diversity and accuracy, such as the use of the validation set, the boosting-based training framework, and the effective ensemble strategy. Last, we evaluate our method on the computer vision(CV) and the natural language processing(NLP) tasks, and the results show that snapshot boosting can get a more balanced trade-off between training expenses and ensemble accuracy than other well-known ensemble methods.

关键词： ensemble learning deep learning boosting neural network snapshot ensemble

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Effects of Lead on the Initial Corrosion Behavior of 316LN Stainless Steel in High-Temperature Alkaline Solution

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Acta Metallurgica Sinica(English Letters) 2019年第1期32卷 89-97页

作者： Jia-Min shao cui-Wei Du Xin Zhang Li-Ying cui Corrosion and Protection Center University of Science and Technology Beijing Nuclear and Radiation Safety Center Ministry of Environmental Protection of P.R.China

The effect of lead on the initial corrosion behavior of 316 LN stainless steel has been investigated by U-bend immersion experiments in 4 wt% NaOH solutions at 300 °C. Follow-up studies after soaking were carried out by scanning electron microscope, energy dispersive X-ray spectrometer, X-ray photoelectron spectrometer, Auger electron spectroscopy and Raman spectroscopy. The results show that lead affects the properties of the oxide film by changing the thickness and composition, which leads to an increase in the sensitivity of stress corrosion cracking of 316 LN stainless steel. Pits and cracks appeared on the surface of 316 LN stainless steel under both lead-free and lead-containing conditions. The corrosion products were oxides of Fe, Cr and Ni, and the main spinel structure on the surface of the film was NiCr_2O_4 under both conditions. However, in the presence of lead, the cracks and pits were more obvious, the thickness of the film increased from 50 to 200 nm, and the amount of protective NiCr_2O_4 decreased. Lead was concluded to be involved in the dehydration reactions in the form of Pb(OH)_2, which affected the normal dehydration process of the hydroxides and inhibited the formation of spinel structures. Because of the above characteristics of lead, the stability of the oxide film and its protection of 316 LN stainless steel were reduced.

关键词： PbSCC Oxide film 316LN High temperature

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Chemometric methods for extracting information from temperature-dependent near-infrared spectra

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Science China Chemistry 2019年第5期62卷 583-591页

作者： Xiaoyu cui Yan Sun Wensheng Cai Xueguang shao Research Center for Analytical Sciences College of ChemistryNankai University Tianjin Key Laboratory of Biosensing and Molecular Recognition State Key Laboratory of Medicinal Chemical Biology Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Xinjiang Laboratory of Native Medicinal and Edible Plant Resources Chemistry College of Chemistry and Environmental ScienceKashgar University

Temperature-dependent near-infrared(NIR) spectroscopy is a new technique for measuring the NIR spectra of a sample at different temperatures. Taking the advantage of the temperature effect, the technique has shown its potential in both quantitative and qualitative analysis. The technique has been proved to be powerful in determination of the analytes in complex samples,particularly in studying the functions of water in aqueous systems due to the significant effect of temperature on the NIR spectra of water. Because of the complicated interactions in the samples and the overlapping of the broad peaks in NIR spectra, it is difficult to extract the temperature-dependent information from the spectra. Chemometric methods, therefore, have been developed for improving the spectral resolution and extracting the temperature-induced spectral information. In this review, recent advances in the studies of chemometric methods and the applications in resolution, quantitative and structural analysis of temperature-dependent NIR spectra were summarized.

关键词： near-infrared spectroscopy temperature effect chemometrics water aquaphotomics

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A variable importance criterion for variable selection in near-infrared spectral analysis

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Science China Chemistry 2019年第2期62卷 271-279页

作者： Jin Zhang Xiaoyu cui Wensheng Cai Xueguang shao Research Center for Analytical Sciences College of Chemistry Nankai University Tianjin Key Laboratory of Biosensing and Molecular Recognition State Key Laboratory of Medicinal Chemical Biology Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) Xinjiang Laboratory of Native Medicinal and Edible Plant Resources Chemistry College of Chemistry and Environmental ScienceKashgar University

Variable selection is a universal problem in building multivariate calibration models, such as quantitative structure-activity relationship(QSAR) and quantitative relationships between quantity or property and spectral data. Significant improvement in the prediction ability of the models can be achieved by reducing the bias induced by the uninformative variables. A new criterion,named as C, is proposed in this study to evaluate the importance of the variables in a model. The value of C is defined as the average contribution of a variable to the model, which is calculated by the statistics of the models built with different combinations of the variables. In the calculation, a large number of partial least squares(PLS) models are built using a subset of variables selected by randomly re-sampling. Then, a vector of the prediction errors, in terms of root mean squared error of cross validation(RMSECV), and a matrix composed of 1 and 0 indicating the selected and unselected variables can be obtained. If multiple linear regression(MLR) is employed to model the relationship between the RMSECVs and the matrix, the coefficients of the MLR model can be used as a criterion to evaluate the contribution of a variable to the RMSECV. To enhance the efficiency of the method, a multi-step shrinkage strategy was used. Comparison with Monte Carlo-uninformative variables elimination(MC-UVE), randomization test(RT) and competitive adaptive reweighted sampling(CARS) was conducted using three NIR benchmark datasets. The results show that the proposed criterion is effective for selecting the informative variables from the spectra to improve the prediction ability of models.

关键词： near-infrared spectroscopy variable selection multivariate calibration multi-step strategy

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Numerical simulation of heat transfer process in cement grate cooler based on dynamic mesh technique

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Science China(Technological Sciences) 2016年第7期59卷 1065-1070页

作者： shao Wei cui Zheng WANG NaiHua CHENG Lin Institute of Thermal Science and Technology Shandong University

A grate cooler is key equipment in quenching clinker and recovering heat in cement production. A two-dimensional numerical model based on a 5000 t/d cement plant is proposed to for a study on the gas-solid coupled heat transfer process between the cooling air and clinker in a grate cooler. In this study, we use the Fluent dynamic mesh technique and porous media model through which the transient temperature distribution with the clinker motion process and steady temperature and pressure distribution are obtained. We validate the numerical model with the operating data of the cooling air outlet temperature. Then, we discuss the amount of mid-temperature air outlet and average diameter of clinker particles, which affect the heat effective utilization and cooling air pressure drop in clinker layer. We found that after adding one more mid-temperature air outlet, the average temperature of the air flowing into the heat recovery boiler increases by 29.04℃ and the ratio of heat effective utilization increases by 5.3%. This means heat recovery is more effective on adding one more mid-temperature air outlet. Further, the smaller the clinker particles, the more is the pressure drop in clinker layer; thus more power consumption is needed by the cooling fan.

关键词： grate cooler gas-solid heat transfer dynamic mesh numerical simulation

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Enhanced flow injection analysis for measurements of S-nitrosothiols species in biological samples using highly selective amperometric nitric oxide sensor

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Chinese Chemical Letters 2012年第2期23卷 229-232页

作者： Chun cui Huang Hui Bo shao Key Laboratory of Cluster Science Ministry of Education of ChinaSchool of ChemistryBeijing Institute of TechnologyBeijing 100081China

A highly selective nitric oxide（NO） sensor is fabricated and applied to devise an enhanced flow injection analysis（FIA） system for S-nitrosothiols（RSNOs） measurement in biological *** NO sensor is prepared using a polytetrafluoroethylene（PTFE） gas-permeable membrane loaded with Teflon AF？ solution,a copolymer of tetrafluoroethylene and 2,2-bis（trifluoroethylene）-4,5-difluoro -l,3-dioxole,to improve *** method is much simpler and possesses good performance over a wide range of RSNOs *** deviation for three parallel measurements of blood plasma is 4.0%.The use of the gas sensing configuration as the detector enhances selectivity of the FIA measurement *** less selective electrochemical detectors that do not use PTFE/Teflon type outer membranes.

关键词： Enhanced FIA method Plasma RSNOs Highly selective NO sensor

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