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Self-reduction Mechanism of Coal Composite Stainless Steel Dust Hot Briquette

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Journal of Iron and Steel Research International 2016年第4期23卷 314-321页

作者： Sok-chol RI Man-sheng CHU shuang-yin chen Zheng-gen LIU Hun HONG School of Metallurgy Northeastern University School of Metallurgical Engineering Kim Chaek University of Technology

To efficiently recycle valuable metals such as chromium and nickel in stainless steel dust, self-reduction ex- periments were carried out to study the reduction mechanism of metal oxides in coal composite stainless steel dust hot briquette, which is defined as a CCSB here. Self-reduction of CCSB is proceeded by volatile matter and fixed carbon contained within CCSB. Experiments were performed to study the effects of temperature and carbon to oxygen （C/OCoal） ratio on self reduction of CCSB. At 1400 and 1450℃, volatile matter in coal used for experiment could take the place of about 40℃ of fixed carbon in coal. Under the present experimental conditions, reduction product of chromium appears as FeCr2O2, Cr2O3, Cr7C3 , and [Cr] in turn during reduction. To evaluate the formation of met al nuggets in self reduction process of CCSB, metal nuggets containing chromium and nickel were observed in outside of reduction products under various conditions, and thermodynamic equilibrium calculation was carried out for possi hie products and formation of molten metal by fixed carbon. SEM and EDS analyses were made for metal nugget and slag in reduced product. The results reveal that it is reasonable to achieve the metal nuggets at 1450℃, 0.8 of C/OCoal ratio and 20 min of reduction time. The nugget formation can indicate one innovative process for comprehensive utilization of stainless steel dust.

关键词： stainless steel dust coal composite hot briquette self reduction metal nugget

Carbothermic Reduction Mechanism of Vanadium-titanium Magnetite

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Journal of Iron and Steel Research International 2016年第5期23卷 409-414页

作者： shuang-yin chen Xiao-jiao FU Man-sheng CHU Xi-zhe LI Zheng-gen LIU Jue TANG School of Metallurgy Northeastern University

To achieve the high-efficiency utilization of vanadium-titanium magnetite（ VTM）,reduction experiments were conducted to determine the carbothermic reduction mechanism of VTM. Effects of volatile matter,temperature,time,and carbon ratio（ molar ratio of fixed carbon in coal to oxygen in iron oxides of VTM） on reduction degree were *** show that reduction degree increases with increasing volatile matter in coal,temperature,time,and carbon *** transformation,microstructure,and reduction path were analyzed by X-ray diffraction,scanning electron microscopy,energy-dispersive X-ray spectroscopy,and Fact Sage 6. 0. The thermoravimetry-differential scanning calorimetry-quadrupole mass spectrometer method was used for kinetic analysis of the main reduction process. Results indicate that the kinetic mechanism follows the principle of random nucleation and growth（ n = 4）,and the activation energy values at 600-900 and 900-1 350 ℃ are 88. 7 and 295. 5 kJ / mol,respectively.

关键词： vanadium-titanium magnetite carbothermic reduction mechanism phase transformation kinetics

Optimization of BF Slag for High Cr_2O_3 Vanadium-titanium Magnetite

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Journal of Iron and Steel Research International 2014年第2期21卷 144-150页

作者： Yong ZHANG Jue TANG Man-sheng CHU Yang LIU shuang-yin chen Xiang-xin XUE School of Material and Metallurgy Northeastern University

In order to clarify the slag system of high Cr2O3 vanadium-titanium magnetite smelting in BF （blast furnace）, the melting properties of slag samples prepared by analytically pure reagents were measured. By means of orthogonal test synthetic weighted score method, the optimal slag for high Cr2O3 vanadium-titanium magnetite was obtained, which contained 10% MgO, 8% TiO2 and 15% Al2O3, with the binary basicity being 1.15. In addition, the effects of basicity, MgO, TiO2 and A12 03 on slag melting properties were investigated by single factor test, and the results showed that, with increasing the basicity or TiO2 content, melting temperature （Tin） increased, whereas initial vis- cosity （r/0） and high temperature viscosity （r/h） decreased. With increasing the MgO content, Tm decreased firstly and then increased. With increasing the Al2 O3 content, Tm increased, and η0 and r/h decreased firstly and then increased.

关键词： high Cr2 03 vanadium-titanium magnetite melting property slag optimization synthetic weighted scoremethod

Comprehensive Utilization of Ludwigite Ore Based on Metallizing Reduction and Magnetic Separation

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Journal of Iron and Steel Research International 2015年第8期22卷 672-680页

作者： Xiao-jiao FU Jia-qi ZHAO shuang-yin chen Zheng-gen LIU Tong-lai GUO Man-sheng CHU School of Materials and Metallurgy Northeastern University

With the aim of high-efficiency utilization of Dandong ludwigite ore, a new process of metallizing reduction and mag- netic separation was proposed, and the effects of reduction temperature, reduction time, carbon ratio, ore size and coal size on the efficiency of the process were investigated in details, and relevant mechanisms were elucidated by SEM and EDS. The optimum technological parameters for metallizing reduction and magnetic separation on ludwigite ore were obtained as reduction tempera- ture of 1 250 ℃, reduction time of 60 min, carbon ratio of 1.4, ore size of 0.500-2.000 mm, and coal size of 0.50-1.50 mm. After adopting the optimum parameters, the iron content and recovery ratio of iron in magnetic substance are 87.78% and 88.02%, re- spectively, while the recovery ratios of boron, magnesium and silicon in non-magnetic substance are 88.86%, 94.60% and 98.66%, respectively. After metallizing reduction and magnetic separation, valuable elements of ludwigite ore could be separated and uti- lized in subsequent steelmaking process and hydrometallurgy process.

关键词： ludwigite ore metallizing reduction magnetic separation valuable element comprehensive utilization

Self-assembly Induced by Complexation of Diblock Copolyelectrolytes and Oppositely Charged Homopolymers

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Chinese Journal of Polymer Science 2024年第9期42卷 1321-1332,I0006页

作者： Ling Zhao Zhi-Yuan yin Jia-Di Jiang Er-Qiang chen shuang Yang Beijing National Laboratory for Molecular Sciences Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationCenter for Soft Mater Science and EngineeringCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China

We investigate the solution self-assembly of a mixture of positively charged homopolymers and AB diblock copolymers,in which the A blocks are negatively charged,and the B blocks are *** electrostatic complexation between oppositely charged polymers drives the formation of many ordered *** microstructures and phase diagrams are calculated using self-consistent field theory(SCFT)based on an ion-pair model with an equilibrium constant K to characterize the strength of binding between positively and negatively charged *** effects of the charge ratio,representing the ratio of charges from the homopolymer over all charges from polymers in the system,on the ordered structure are systematically studied,both for hydrophobic and hydrophilic A *** charge ratio plays an important role in determining the phase boundaries in the phase diagram of salt concentration versus polymer *** also provide information about the varying tendency of the domain spacing and core size of the spherical phase when the charge ratio is changed,and the results are in good agreement with *** studies provide a deep understanding of the self-assembled microstructures of oppositely charged diblock copolymer-homopolymer systems.

关键词： Self-assembly Polyelectrolyte complexation Self-consistent field theory Ion-pair

Lipase and photodecarboxylase coexpression: A potential strategy for alkane-based biodiesel production from natural triglycerides

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Chinese Journal of Chemical Engineering 2024年第3期67卷 238-246页

作者： Yong-Yi Zeng Xin-Yi Xu Jin-Xuan Xie Wen-Li chen Lan Liu Xin-Jian yin Bi-shuang chen School of Marine Sciences Sun Yat-Sen UniversityZhuhai 519080China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519080China

Alkane-based biodiesel is considered the next generation of biodiesel owing to its potential environmental benefits and the fact that it exhibits much higher specific caloric values than traditional ***,the formidable obstacle impeding the commercialization of this cutting-edge fuel alternative lies in the cost associated with its *** this study,an engineered strain Escherichia coli(***)showcasing harmonized coexpression of a lipase(from Thermomyces lanuginosus lipase,TLL)and a fatty acid photodecarboxylase(from Chlorella variabilis,CvFAP)was first constructed to transform triglycerides into *** potential of *** BL21(DE3)/pRSFDuet-1-TLL-CvFAP for alkane synthesis was evaluated with tripalmitin as a model substrate under various process *** a comprehensive examination of the reaction parameters,the scope of the biotransformation was expanded to‘real’substrates(vegetable oils).The results showed that bioderived oils can be transformed into alkanes with high yields(0.80-10.20 mmol·L^(-1))under mild conditions(35℃,pH 8.0,and 36 h)and blue light *** selected processes were performed on an increased lab scale(up to 100 ml)with up to 24.77 mmol·L^(-1) tripalmitin,leading to a yield of 18.89 mmol·L^(-1) *** the employment of a method for efficiently producing alkanes under mild conditions and a simple procedure to isolate alkanes from the reaction system,the utilization of sustainable biomass as a fundamental feedstock emerges as the primary solution to lower the cost of alkane-based ***,this study proposes a readily implementable and highly effective approach for alkane-based biodiesel production.

关键词： Alkane-based biodiesel Renewable biomass Co-overexpression Lipase Photodecarboxylase

Electronic structure engineering of single atomic sites by plasmoninduced hot electrons for highly efficient and selective photocatalysis

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Nano Research 2024年第8期17卷 6960-6967页

作者： Xiaoya Huang Xinyuan Li Akang chen Hongfei Gu Shouyuan Li Tailei Hou Shuwen Zhu shuang Yu yin Song Jiatao Zhang Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications MIIT Key Laboratory of Medical Molecule Science and Pharmaceutical EngineeringMOE Key Laboratory of Cluster ScienceSchool of Chemistry and Chemical EngineeringSchool of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China MIIT Key Laboratory of Complex-field Intelligent Exploration School of Optics and PhotonicsBeijing Institute of TechnologyBeijing 100081China

Single atom(SA)catalysts have achieved great success on highly selective heterogeneous catalysis due to their abundant and homogeneous active *** electronic structures of these active sites,restrained by their localized coordination environments,significantly determine their catalytic performances,which are difficult to ***,we investigated the effect of localized surface plasmon resonance(LSPR)on engineering the electronic structures of single atomic ***,core–shell structures consisted of Au core and transition metal SAs loaded N-doped carbon(CN)shell were constructed,namely Au@M-SA/CN(M=Ni,Fe,and Co).It was demonstrated that plasmon-induced hot electrons originated from Au were directionally injected to the M-SAs under visible light irradiation,which significantly changed their electronic structures and meanwhile facilitated improved overall charge separation *** as-prepared Au@Ni-SA/CN exhibited highly efficient and selective photocatalytic CO_(2) reduction to CO performance,which is 20.8,17.5,and 6.9 times those of Au nanoparticles,Au@CN,and Ni-SA/CN,*** spectroscopy analysis and theoretical calculations confirmed that the plasmon enhanced Ni-SA/CN sites featured increased charge density for efficient intermediate activation,contributing to the superb photocatalytic *** work provides a new insight on plasmon and atomic site engineering for efficient and selective catalysis.

关键词： single atom catalysts plasmon enhancement coupling effect photocatalysis CO_(2) reduction

Quantum key distribution over a mimicked dynamic-scattering channel

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Science China(Information Sciences) 2024年第4期67卷 323-330页

作者： Qi-Hang LU Fang-Xiang WANG Wei chen Hai-Yang FU yin-Jie LU shuang WANG De-Yong HE Zhen-Qiang yin Guang-Can GUO Zheng-Fu HAN CAS Key Laboratory of Quantum Information University of Science and Technology of China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei National Laboratory University of Science and Technology of China

Free-space quantum key distribution(QKD) plays an important role in the global quantum network. However, free space channels suffer from the atmospheric turbulence and scattering effects of haze,fog, and dust, which significantly weaken the performance of QKD or even block the secure quantum ***, we prove the performance of QKD over a dynamic scattering channel can be enhanced significantly using a fast wavefront shaping technique. The system achieves on average 10-dB enhancement of quantum transmission efficiency and establishes a secure quantum link for QKD. Our work demonstrates the feasibility of QKD through free-space dynamic scattering channels and enhances the deployment capability of complex-channel QKD system.

关键词： quantum key distribution free space channel channel turbulence channel scattering wavefront shaping

Anti-saturation fault-tolerant adaptive torsional vibration control with fixed-time prescribed performance for rolling mill main drive system

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Journal of Iron and Steel Research International 2024年第3期31卷 660-669页

作者： shuang Liu chen Du Cong Zhang Zhen-hua Bai Key Lab of Industrial Computer Control Engineering of Hebei Province Yanshan UniversityQinhuangdao 066004HebeiChina National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao 066004HebeiChina

An anti-saturation fault-tolerant adaptive torsional vibration control method with fixed-time prescribed performance for the rolling mill main drive system(RMMDS)was investigated,which is affected by control input saturation,actuator faults,sensor measurement errors,and parameter ***,we gave a continuously differentiable saturation function to approximate the control input saturation characteristic of the RMMDS,translating the saturation characteristic into the matched uncertainty and unknown time-varying gain in the ***,an RMMDS mathematical model with unmatched uncertainty and unknown time-varying gain was developed,taking into account the presence of control input saturation,actuator faults,sensor measurement errors,and parameter *** on the established mathematical model,an error transformation model of the roll speed tracking was constructed by the equivalent error transformation *** to the error transformation model,a barrier Lyapunov function and a novel adaptive controller were studied to ensure that the roll speed tracking error always evolves inside a fixed-time asymmetric ***,numerical simulations were performed in Matlab/Simulink to verify the effectiveness and superiority of the proposed control method in suppressing the RMMDS torsional vibration.

关键词： Fixed-time prescribed performance Control input saturation Actuator fault Unknown time-varying gain Adaptive control Asymmetric constraint