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Research on mold flux for hypo-peritectic steel at high casting speed

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Journal of University of Science and Technology Beijing 2007年第3期14卷 219-224页

作者： heming zhao Xinhua Wang Jiongming Zhang Metallurgical and Ecological Engineering School University of Science and Technology Beijing Beijing 100083 China

Mold fluxes having adaptable properties were developed in the laboratory to solve quality defects, such as depressions and longitudinal cracks when casting hypo-peritectic steel at high casting speed. Firstly, the effect of components on the high basicity mold flux properties was first studied using the orthogonal method. In the scope of the studied content, Li2O has the largest effect on the melting temperature, and the least effect on the viscosity; CaF2 has the largest effect on the viscosity, and the least effect on the melting temperature; Na2O and CaO/SiO2 have no obvious influence on the melting temperature and viscosity. Secondly, two powders （Z1 and Z6） have reasonable viscosity-temperature curves, higher solidification temperatures, and porous structure after solidification, but the crystal property of Z6 is worse than that of Z1, and thus Z1 is more suitable for continuous casting hypo-peritectic steel at high casting speed. Thirdly, a higher basicity of powder, a less free enthalpy of crystal compound, and a lower baffle energy are good for a higher tendentiousness of crystal.

关键词： hypo-peritectic steel mold flux crystal property heat flux

Heterogeneous Microstructure-Induced Mechanical Responses in Various Sub-Zones of EH420 Shipbuilding Steel Welded Joint Under High Heat Input Electro-Gas Welding

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Acta Metallurgica Sinica(English Letters) 2021年第10期34卷 1427-1433页

作者： Xu Xie Tan zhao heming zhao Song Li Cong Wang School of Metallurgy Northeastern UniversityShenyang 110819China State Key Laboratory of Metal Material for Marine Equipment and Application Angang Steel Co.Ltd.Anshan 114021China Minmetals Yingkou Medium Plate Co. Ltd.Yingkou 115005China Nanjing Steel Co. Ltd.Nanjing 210035China State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China

Heterogeneous microstructure-induced mechanical responses in EH420 shipbuilding steel welded joint by electro-gas welding processed have been systematically studied by scanning electron microscopy,electron backscatter diffraction and mechanical *** with the coarse-grained heat-affected zone(CGHAZ),the weld metal presents higher toughness(129.3 J vs.37.3 J)as it contains a large number of acicular ferrites with high-angle grain boundaries(frequency 79.2%)and special grain boundary∑3(frequency 55.3%).Moreover,coarse austenite grains in CGHAZ and slender martensite–austenite constituents between bainite laths may likely facilitate crack *** ferrites and tempered pearlites formed at the junction of the fine-grained heat-affected zone and the intercritical heat-affected zone induced a softened zone with an average hardness of 185 HV0.5,which is the main reason for the occurrence of tensile fracture.

关键词： Heterogeneous microstructure Mechanical properties Electro-gas welding High heat input Shipbuilding steel

Effect of SEN structure on the mold level fluctuation and heat transfer for a medium thin slab caster

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Journal of University of Science and Technology Beijing 2008年第2期15卷 120-124页

作者： heming zhao Xinhua Wang Jiongming Zhang Wanjun Wang School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China

It is important to select suitable parameters of a submerged entry nozzle （SEN） for optimizing the flow and temperature patterns in a mold. The effect of SEN design on the mould level stability, meniscus steel flow velocity, and heat transfer of the mold of a medium thin slab caster was studied by means of 1：1 water modeling and industrial testing. The advantages of a 2-port SEN compared with a 3-port SEN are the following： more optimal flow patterns with a lower mold level fluctuation and a lower meniscus steel flow velocity; proper powder consumption without slag bears due to a reasonable liquid powder thickness. The argon flow rate can be reduced and the mold average heat flux and temperature near the edges of the copper plate are reduced. At a casting speed of 2.5 m·min^-1, the mold level fluctuation lies within ＋5 mm. In addition, soft cooling of the steel shell in the mold is realized, which is suitable for casting crack susceptible steel grades.

关键词： submerged entry nozzle mold level fluctuation heat transfer water model

Speech enhancement method combining amplitude spectrum and power spectrum dictionaries

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Chinese Journal of Acoustics 2021年第4期40卷 611-626页

作者： NIE Lingzi CHEN Xueqin zhao heming School of Electronic and Information Engineering Soochow UniversitySuzhou215006

An improved speech enhancement method based on sparse representation of spec-tral features is proposed from the perspective of dual dictionary learning,noise power spectrum estimation and speech amplitude spectrun *** the dictionary learning stage,the power spectrun and amplitude spectrum features are combined,and the discriminative dictionary learning method is used to reduce the coherence of the spech dictionary and the noise *** the speech enhancement stage,a noise power spectrum estimation method is proposed to track and estimate the nonstationary *** the inconsistency be-tween the amplitude spectrum and the power spectrum characteristics for different noises,the corresponding reconstruction weight cofficient is *** two-channel signals recovered from the amplitude spectrum and the power spectrum are adaptively weighted,and the en-hanced speech signal is obtained by combining the phase compensation *** shown in experimental results,compared with the single spectral feature speech enhancement method,the proposed method improves the performance of speech enhancement method by 31.6%on average under stationary and nonstationary noise environments.

关键词： power spectrum noise

Exploring the feasibility of prestressed anchor cables as an alternative to temporary support in the excavation of super-large-span tunnel

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Railway Engineering Science 2024年第3期32卷 344-360页

作者： Shunhua Zhou Yuyin Jin Zhiyao Tian Chunhua Zou heming zhao Zengrun Miao Shanghai Key Laboratory of Rail Infrastructure Durability and System Safety Tongji UniversityShanghai 201804China Key Laboratory of Road and Traffic Engineering of the Ministry of Education Tongji UniversityShanghai 201804China China Railway Construction Corporation Limited Beijing 100855China The 2nd Engineering Co. Ltd.of China Railway Construction Bridge Engineering Bureau GroupShenzhen 518083China China Railway Construction Bridge Engineering Bureau Group Co. LtdTianjin 300300China

Excavating super-large-span tunnels in soft rock masses presents significant *** ensure safety,the sequential excavation method is commonly *** utilizes internal temporary supports to spatially partition the tunnel face and divide the excavation into multiple ***,these internal supports generally impose spatial constraints,limiting the use of large-scale excavation equipment and reducing construction *** address this constraint,this study adopts the“Shed-frame”principle to explore the feasibility of an innovative support system,which aims to replace internal supports with prestressed anchor cables and thus provide a more spacious working space with fewer internal *** evaluate its effectiveness,a field case involving the excavation of a 24-m span tunnel in soft rock is presented,and an analysis of extensive field data is conducted to study the deformation characteristics of the surrounding rock and the mechanical behavior of the support *** results revealed that prestressed anchor cables integrated the initial support with the shed,creating an effective“shed-frame”system,which successively maintained tunnel deformation and frame stress levels within safe regulatory ***,the prestressed anchor cables bolstered the surrounding rock effectively and reduced the excavation-induced disturbance zone *** summary,the proposed support system balances construction efficiency and *** field experiences may offer valuable insights into the popularization and further development of prestressed anchor cable support systems.

关键词： Super-large-span tunnel Construction safety Sequential excavation method Shed-frame principle Prestressed anchor cables

Deceptive Chinese speech detection based on sparse decomposition of cepstral feature

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Chinese Journal of Acoustics 2019年第1期38卷 99-112页

作者： FAN Xiaohe zhao heming CHEN Xueqin ZHOU Yan Electronic Information Institute of Soochow University College of Electronic Information Engineering Suzhou Vocational University

In order to improve the performance of deception detection based on Chinese speech signals, a method of sparse decomposition on spectral feature is proposed. First, the wavelet packet transform is applied to divide the speech signal into multiple sub-bands. Band cepstral features of wavelet packets are obtained by operating the discrete cosine transform on loga?rithmic energy of each sub-band. The cepstral feature is generated by combing Mel Frequency Cepstral Coefficient and Wavelet Packet Band Cepstral Coefficient. Second, K-singular value decomposition algorithm is employed to achieve the training of an over-complete mixture dictionary based on both the truth and deceptive feature sets, and an orthogonal matching pursuit algorithm is used for sparse coding according to the mixture dictionary to get sparse ***, recognition experiments axe performed with various classified modules. Experimental results show that the sparse decomposition method has better performance comparied with con?ventional dimension reduced methods. The recognition accuracy of the method proposed in this paper is 78.34%, which is higher than methods using other features, improving the recognition ability of deception detection system significantly.

关键词： Cepstrum features Voice detection Chinese speech signal

2009/2010 China Top 500 Textile & Apparel Competitiveness Enterprises Announced

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纺织服装周刊 2010年第37期 8-9页

作者： zhao heming

2009/2010 China Top 500 Tex-tile & Apparel Competitiveness Enterprises List was announced on Sept. 19th in Haining Zhejiang. The 2009/2010 China Textile & Apparel Enterprises Competitiveness Analysis Report, and the t... 详细信息

关键词： 2010 China Top 500 Textile Co Apparel Competitiveness Enterprises Announced

Application of improved U-Net network with attention mechanism in end-to-end speech enhancement

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Chinese Journal of Acoustics 2022年第4期41卷 390-403页

作者： WU Ruiqin CHEN Xueqin YU Jie WANG Lirong zhao heming School of Electronic and Information Engineering Soochow UniversitySuzhou 215006

An improved U-Net(Attention Dilated Convolution U-Net,ADC-U-Net)network model for end-to-end speech enhancement is designed based on the U-Net *** with the baseline U-Net network,the dilated convolution is added to reduce the loss of information caused by ***,the attention mechanism structure is introduced,which combines more contextual information of noisy speech to extract deeper and richer feature *** proposed model avoids the extraction of features with distinct step,so it does not need three steps of traditional methods,including feature extraction,feature denoising and waveform *** proposed network model obtains complex structural features to represent speech through multi-level and multi-scale *** quality and intelligibility of enhanced speech are evaluated by several subjective and objective *** data show that the proposed algorithm performs well in noise suppression and adaptability,and has advantage over baseline U-Net network and other models in speech quality and intelligibility.

关键词： network speech mechanism

Research advances in peptide-drug conjugates

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Acta Pharmaceutica Sinica B 2023年第9期13卷 3659-3677页

作者： Liming Gong heming zhao Yanhong Liu Hao Wu Chao Liu Shuangyan Chang Liqing Chen Mingji Jin Qiming Wang Zhonggao Gao Wei Huang State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100050China Beijing Key Laboratory of Drug Delivery Technology and Novel Formulations Department of PharmaceuticsInstitute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100050China Department of Pharmacy Yanbian UniversityYanji 133000China

Peptide-drug conjugates(PDCs)are drug delivery systems consisting of a drug covalently coupled to a multifunctional peptide via a cleavable *** an emerging prodrug strategy,PDCs not only preserve the function and bioactivity of the peptides but also release the drugs responsively with the cleavable property of the *** the ability to significantly improve the circulation stability and targeting of drugs in vivo and reduce the toxic side effects of drugs,PDCs have already been extensively applied in drug ***,we review the types and mechanisms of peptides,linkers and drugs used to construct PDCs,and summarize the clinical applications and challenges of PDC drugs.

关键词： Peptide-drug conjugates Peptides Linkers Drug delivery systems Prodrug strategy