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Design and analysis of a mode-hop-free tunable laser based on etched diffraction grating

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Journal of Zhejiang University-Science C(Computers and Electronics) 2010年第10期11卷 793-797页

作者： Rui-xing ZENG Lei WANG Jian-jun he Center for Integrated Optoelectronics State Key Lab of Modern Optical Instrumentation Zhejiang University Hangzhou 310027 China

A novel semiconductor laser which can achieve mode-hop-free tuning is proposed. The device consists of an etched diffraction grating （EDG） as a dispersive element to provide the mode selection function and an active waveguide to provide optical gain for the laser. The slab waveguide region of the EDG contains a tuning section covered by an electrode to inject a tuning current, and thus changes the refractive index. Mode-hop-free tuning is achieved by specially designing the shape of the tuning section, so that the tuning rate of the central wavelength reflected by the EDG and the tuning rate of the resonant wavelength of the laser cavity are equal. An optimized tuning section shape is designed to obtain the largest tuning range within a limited current range. Numerical simulation is presented to demonstTate the mode-hop-free tuning operation.

关键词： Semiconductor laser Integrated optics Etched diffraction grating

Effects and Mechanisms of RE on Impact Toughness and Fracture Toughness of Clean heavy Rail Steel

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Journal of Iron and Steel Research International 2011年第3期18卷 52-58页

作者： LIU Cheng-jun HUANG Ya-he JIANG Mao-fa School of Materials and Metallurgy Northeastern UniversityShenyang 110004LiaoningChina

Clean high carbon heavy rail steel was prepared by the process of vacuum induction furnace smelting,forging and *** of RE on the impact toughness and fracture toughness for clean high carbon steel were *** addition,the appropriate range of RE content for clean high carbon steel was *** the austenite grain size and pearlite lamellar spacing decreased due to small amount of RE,consequently the impact toughness and fracture toughness were improved *** the RE content exceeded a critical value,the pearlite lamellar spacing was increased,because RE was segregated on the austenite grain boundaries,damaged the orientation relationship of pearlite transformation,caused the disorder growth and morphology degenerating of *** the increasing of RE content,both the impact toughness and fracture toughness of clean high carbon steel were gradually increased at first and then *** was found that when the RE content was between 0.0081% and 0.0088%,both the impact toughness and fracture toughness of clean high carbon heavy rail steel were the *** maximum ballistic work was 21.2 J（20 ℃） and 12.2 J（-20 ℃）,*** maximum plane-strain fracture toughness was 45.67 MPa·m1/2（20 ℃） and 37.04 MPa·m1/2（-20 ℃）,respectively.

关键词： rare earth high carbon steel heavy rail steel clean steel impact toughness fracture toughness

Enhancement of Formation of Polar Microenvironment in Polymer by Compressed CO_(2)

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Chinese Chemical Letters 2002年第9期13卷 901-902页

作者： Rui ZHANG jun he jun LIU Bu Xing HAN Guan Ying YANG The Center for Molecular Sciences Institute of ChemistryChinese Academy of SciencesBeijing 100080

The copolymer (EO)22(PO)52(EO)22 in p-xylene can solubilize much more water in the presence of compressed CO2 than the case without CO2.

关键词： Reverse micelles polymer surfactant carbon dioxide.

Kinetic study on co-combustion of pulverized anthracite and bituminite for blast furnace injection

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Journal of Iron and Steel Research International 2021年第8期28卷 949-964页

作者： Li-chun Yang Qing-hai Pang Zhi-jun he jun-hong Zhang Wen-long Zhan Nan Lü School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051LiaoningChina

Combustion behavior of single pulverized coals(PCs)and co-combustion characteristics of anthracite(AT)and bituminite(BT)blends with 20 wt.%volatile were studied by thermogravimetric *** results indicated that reaction characteristics of PCs were closely related to their functional group structure and consequently,the pyrolysis of PCs with highly active functional groups initiated at lower *** was also noticed that the discrepancy of functional group structures between AT and BT might impair their interaction during *** early exhaust of BT at low temperatures would possibly lead to an independent combustion of volatile and residual carbon and eventually the inefficient combustion of their ***,the mixing of AT and BT with similar functional group structures was more likely to achieve blends with superior combustion ***,non-isothermal kinetic analysis mani-fested that the combustion of blends followed random pore model(RPM),and therefore,the parameters calculated by RPM were more accurate to describe their combustion *** kinetic calculation results showed that the activation energy required for decomposition of blends in early combustion stage was much lower owing to the excellent activity of volatile,while residual carbon with stable aromatic hydrocarbon demanded more energy to initiate its combustion.

关键词： Blast furnace Pulverized coal Coal blend Non-isothermal combustion Kinetic analysis

Effect of Calix[4]pyrrole as Addition Reagent on Anions Separation in Capillary Zone Electrophoresis (CZE)

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Chinese Chemical Letters 2001年第6期12卷 511-512页

作者： Li jun he Qing Song CAI Shi jun SHAO Sheng Xiang JIANG Lanzhou Institute of Chemical Physics Chinese Academy of sciencesLanzhou 730000

Supramolecular interaction of calix[4]pyrroles with several inorganic anions is reported by addition of calix[4]pyrroles to background electrolyte (BGE) in CZE. The retention time (t(R)) of all anions increased with i... 详细信息

关键词： Supramolecular interaction calixpyrroles CZE retention time.

Modified sewage sludge as temporary landfill cover material

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Water Science and Engineering 2015年第3期8卷 257-262页

作者： jun he Feng Li Yong Li Xi-lin Cui College of Civil and Architectural Engineering Hubei University of Technology

In order to study the feasibility of modified sewage sludge as landfill cover material and its performance in a complex landfill environment, strength and hydraulic conductivity tests were conducted. The permeability requirements for daily and interim covers were analyzed first. Based on saturated-unsaturated seepage calculations, it is suggested that approximately 1.0×10^-4 cm/s and 1.0 × 10^-5 cm/s are the appropriate values for the hydraulic conductivities of daily and interim covers, respectively. The strength and permeability requirements of the mixtures, when used as an interim cover, can be met at a sludge：lime：cement：silt：tire-derived aggregate （TDA） weight ratio of 100：15：5：70：15. Results also demonstrate that the solid content ratio of modified sewage sludge, which should be greater than 60% when modified sewage sludge is used as a temporary cover material, is crucial to both strength and hydraulic performance. In addition, as the duration of soaking of modified sewage sludge in synthetic leachate increases, the unconfined compressive strength increases, and the hydraulic conductivity decreases slightly or fluctuates between 1.0×10^-5 cm/s and 1.0 × 10^-6 cm/s, still meeting the requirements for an interim cover. The reduction in hydraulic conductivity of modified sewage sludge under the effect of synthetic leachate, as well as the long-term and environmental performance of the modified sewage sludge, should be examined in future studies.

关键词： Modified sewage sludge Temporary cover Hydraulic conductivity Unconfined compressive strength Soaking

Chemical synthesis and characterization of manganese oxide coated Ni particles

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Science China(Physics,Mechanics & Astronomy) 2013年第8期56卷 1508-1513页

作者： AN Jing XU LiHong he jun ZHAO DongLiang LIU ZhongYuan Department of Functional Material Research Central Iron and Steel Research Institute State Key Lab of Metastable Materials Science and Technology Yanshan University

Nanosized Ni particles with an average diameter of about 8 nm were prepared by reducing of NiCl 2 with sodium borohydride (NaBH 4 ) in aqueous solution. By moderate annealing in protective atmosphere, the composite grew up to be 15-20 nm particles. Both of the as-prepared and annealed Ni particles were coated by a layer of manganese oxide via decomposition reaction in aqueous KMnO4 solution. Hysteresis loops of as-prepared samples show a large increase in the magnetization with decreasing temperature and an unsaturated component at high magnetic field. In contrast, the ferromagnetic characteristics of annealed one are much stronger with large magnetization and coercivity. The thermomagnetic curves verified the coexistence of ferromagnetic Ni and antiferromangetic Mn oxide phases. But there exists no exchange bias behavior in the samples, even though the interface structure between the ferromagnetic Ni core and the antiferromagnetic manganese oxides has been distinctly formed. The absence of exchange bias probably originates from the weak ferromagnetic characteristic of Ni cores.

关键词： nanoparticles chemical reduction core-shell structure magnetic property

Effects of leachate infiltration and desiccation cracks on hydraulic conductivity of compacted clay

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Water Science and Engineering 2015年第2期8卷 151-157页

作者： jun he Yu Wang Yong Li Xiao-chen Ruan College of Civil and Architectural Engineering Hubei University of Technology

Both cracks in clay liner and the complex composition of landfill leachate might have effects on the hydraulic conductivity of a compacted clay liner. In this study, the hydraulic conductivities of natural clay and bentonite-modified clay with and without desiccation cracks were measured, respectively, using three types of liquids as permeating liquid： 2 500 mg/L acetic acid solution, 0.5 mol/L CaCl2 solution, and tap water. When tap water was adopted as the permeating liquid, desiccation cracks resulted in increases in the average value of hydraulic conductivity： a 25-fold increase for the natural clay and a 5.7-fold increase for the bentonite-modified clay. It was also found out that the strong selfhealing capability of bentonite helped to reduce the adverse impact of cracks on hydraulic performance. In contrast to tap water, simulated leachates（acetic acid and CaCl2 solutions） show no adverse effect on the hydraulic conductivities of natural and bentonite-modified clays. It is concluded that desiccation cracks and bentonite have more significant effects on hydraulic performance than simulated leachates.

关键词： Natural clay Bentonite-modified clay Hydraulic conductivity Solution Desiccation crack

Effect of matrix sub-layer interfacial fracture on residual strength improvement of the fatigued carbon/carbon composites

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Journal of Materials Science & Technology 2018年第7期34卷 1243-1249页

作者： Jing Cheng he-jun Li Shou-yang Zhang Li-zhen Xue state Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi'an 710072 China

In the present study, flexural behavior of carbon fber reinforced pyrolytic carbon matrix composites （C/C composites） before and after fatigue tests had been studied. The results showed that the residual flexural strengths of the samples had been improved after fatigue tests, and the fracture mechanisms of the original and post-fatigue specimens had some differences. Fracture mechanism of the original specimens could be described as fiber/matrix interfacial de-bonding, and the dominant damage of the post-fatigue specimens could be regarded as pyrolytic carbon sub-layers＇ step-delamination. The degradation of matrix sub-layer interfacial bonding strength was beneficial to improve the mechanical properties of C/C composites.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.

关键词： Carbon/carbon composites Fatigue behavior Interface Strengthening mechanism