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Effects of the extrusion parameters on microstructure,texture and room temperature mechanical properties of extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 136-146页

作者： Chenjin Zhang Guangyu Yang Lei Xiao Zhiyong Kan Jing Guo Qiang Li Wanqi Jie State key laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China College of Materials Science and Engineering Fuzhou UniversityFuzhou 350108China College of Chemistry and environmental Science Qujing Normal UniversityQujing 655011China

Microstructure,texture,and mechanical properties of the extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy were investigated at different extrusion temperatures(260 and 320℃),extrusion ratios(10:1,15:1,and 30:1),and extrusion speeds(3 and 6 mm/s).The experimental results exhibited that the grain sizes after extrusion were much finer than that of the homogenized alloy,and the second phase showed streamline distribution along the extrusion direction(ED).With extrusion temperature increased from 260 to 320℃,the microstructure,texture,and mechanical properties of alloys changed *** dynamic recrystallization(DRX)degree and grain sizes enhanced as the extrusion ratio increased from 10:1 to 30:1,and the strength gradually decreased but elongation(EL)*** the extrusion speed increased from 3 to 6 mm/s,the grain sizes and DRX degree increased significantly,and the samples presented the typical-rare-earth(RE)*** alloy extruded at 260℃ with extrusion ratio of 10:1 and extrusion speed of 3 mm/s showed the tensile yield strength(TYS)of 213 MPa and EL of 30.6%.After quantitatively analyzing the contribution of strengthening mechanisms,it was found that the grain boundary strengthening and dislocation strengthening played major roles among strengthening *** results provide some guidelines for enlarging the industrial application of extruded Mg-RE alloy.

关键词： Mg-rare earth alloys extrusion temperature extrusion ratio extrusion speed strengthening mechanisms

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1D Acoustic Velocity-Independent DOA Estimation Method with Arbitrary Arrays

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Journal of Communications and Information Networks 2020年第2期5卷 121-129页

作者： Gengxin Ning Liang Xie Xiaopeng Li Jun Zhang School of Electronic Information South China University of TechnologyGuangzhou 510000China key laboratory of Marine environmental survey technology and application Ministry of Natural ResourcesGuangzhou 510300China

The performance of conventional direction of arrival(DOA)method is greatly affected by the uncertainty of wave velocity in underwater *** solve this problem,an acoustic velocity-independent method is proposed to estimate the underwater DOA using two arbitrary intersecting uniform linear arrays in this *** introducing the additional array compared to the conventional DOA methods,the proposed algorithm can make its performance independent of the acoustic velocity through the geometric relationship between those two *** simulation results demonstrate that the proposed method is more accurate and robust than other methods in an unknown sound velocity.

关键词： underwater DOA estimation arbitrary intersecting uniform linear array acoustic velocityindependent method

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Acoustic Velocity-Independent 2-D DOA Estimation for Underwater application

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Journal of Communications and Information Networks 2022年第4期7卷 457-466页

作者： Gengxin Ning Zhenfeng Liao Xiaopeng Li Cui Yang School of Electronic and Information Engineering South China University of TechnologyGuangzhou 510641China key laboratory of Marine environmental survey technology and application Ministry of Natural ResourcesGuangzhou 510300China

In this paper,an acoustic velocityindependent two-dimensional direction of arrival(2-D DOA)estimation for underwater application is presented to eliminate the effect of the inaccurate acoustic velocity *** to the geometric relationship between the linear arrays,the proposed method employs the cross correlation matrix(CCM)of the data received by three crossed linear arrays to remove the acoustic velocity *** simulation results demonstrate that the proposed method is not susceptible to the acoustic *** a single source,the proposed method outperforms the conventional method in all *** multiple sources,there is a little performance degradation for the proposed method compared with the conventional ***,the proposed method displays a better performance than the conventional method in situations where the signal to noise ratio(SNR)is extremely low or the acoustic velocity estimation error is ***,the computational complexity of the proposed method is lower than that of the conventional method using the same amount of sensors in total,while the performance is still acceptable.

关键词： velocity-independent underwater 2-D DOA

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Aerobic N_2O emission for activated sludge acclimated under different aeration rates in the multiple anoxic and aerobic process

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Journal of environmental Sciences 2016年第5期28卷 70-79页

作者： Huoqing Wang Yuntao Guan Min Pan Guangxue Wu key laboratory of Microorganism application and Risk Control of Shenzhen Graduate School at Shenzhen Tsinghua University environmental Science and technology Xiamen University of Technology

Nitrous oxide（N_2O） is a potent greenhouse gas that can be emitted during biological nitrogen removal. N_2O emission was examined in a multiple anoxic and aerobic process at the aeration rates of 600 m L/min sequencing batch reactor（SBRL） and 1200 m L/min（SBRH）.The nitrogen removal percentage was 89% in SBRLand 71% in SBRH, respectively. N_2O emission mainly occurred during the aerobic phase, and the N_2O emission factor was 10.1%in SBRLand 2.3% in SBRH, respectively. In all batch experiments, the N_2O emission potential was high in SBRLcompared with SBRH. In SBRL, with increasing aeration rates, the N_2O emission factor decreased during nitrification, while it increased during denitrification and simultaneous nitrification and denitrification（SND）. By contrast, in SBRHthe N_2O emission factor during nitrification, denitrification and SND was relatively low and changed little with increasing aeration rates. The microbial competition affected the N_2O emission during biological nitrogen removal.

关键词： Aeration rate Nitrous oxide Biological nitrogen removal Multiple anoxic and aerobic Nitrite accumulation

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CVOCs elimination by catalytic combustion

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材料导报 2019年第18期33卷 3003-3004页

作者：郭利民 School of environmental Science and technology Huazhong University of Science and Technology Hubei key laboratory of Processing and application of Catalytic Materials Huanggang Normal University

Chlorinated volatile organic compounds(CVOCs)are widely used in industry as solvents intermediates,which are highly toxic and a contributor for secondary organic aerogels,tropospheric ozone and photochemical smog[1].Many technologies have been developed to eliminate CVOCs *** combustion is regarded as one of the most economical and reliable *** development of catalytic combustion system includes exploring reaction devices,reaction processes and catalysts,among which the key task is to develop highperformance catalysts.

关键词： CVOCs Elimination Catalytic Combustion highperformance catalysts

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Influence of heavy ion irradiation on DC and gate-lag performance of AlGaN/GaN HEMTs

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Chinese Physics B 2015年第5期24卷 433-437页

作者：雷志锋郭红霞曾畅陈辉王远声张战刚 key laboratory of Low Dimensional Materials & application technology of Ministry of Education Xiangtan University Science and technology on Reliability Physics and application of Electronic Component laboratory China Electronic Product Reliability and Environmental Testing Research Institute Northwest Institute of Nuclear technology

AlGaN/GaN high electron mobility transistors （HEMTs） were irradiated by 256 MeV 127I ions with a fluence up to 1 × 10^10 ions/cm2 at the HI-13 heavy ion accelerator of the China Institute of Atomic Energy. Both the drain current ld and the gate current Ig increased in off-state during irradiation. Post-irradiation measurement results show that the device output, transfer, and gate characteristics changed significantly. The saturation drain current, reverse gate leakage current, and the gate-lag all increased dramatically. By photo emission microscopy, electroluminescence hot spots were found in the gate area. All of the parameters were retested after one day and after one week, and no obvious annealing effect was observed under a temperature of 300 K. Further analysis demonstrates that swift heavy ions produced latent tracks along the ion trajectories through the hetero-junction. Radiation-induced defects in the latent tracks decreased the charges in the two-dimensional electron gas and reduced the carrier mobility, degrading device performance.

关键词： GaN HEMTs irradiation heavy ions

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Seasonal variation in the three-dimensional structures of coastal thermal front off western Guangdong

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Acta Oceanologica Sinica 2021年第7期40卷 88-99页

作者： Yan Zhang Lili Zeng Qiang Wang Bingxu Geng Changjian Liu Rui Shi Na Liu Weiping Wang Dongxiao Wang South China Sea Marine survey and technology Center Ministry of Natural ResourcesGuangzhou 510300China State key laboratory of Tropical Oceanography(LTO) South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China key laboratory of Marine environmental survey technology and application Ministry of Natural ResourcesGuangzhou 510300China

The seasonal structure and dynamic mechanism of oceanic surface thermal fronts(STFs)along the western Guangdong coast over the northern South China Sea shelf were analyzed using in situ observational data,remote sensing data,and numerical *** in situ and satellite observations show that the coastal thermal front exhibits substantial seasonal variability,being strongest in winter when it has the greatest extent and strongest sea surface temperature *** winter coastal thermal front begins to appear in November and disappears after the following *** runoff water is more plentiful in summer,the front is weak in the western part of *** frontal intensity has a significant positive correlation with the coastal wind speed,while the change of temperature gradient after September lags somewhat relative to the alongshore *** numerical simulation results accurately reflect the seasonal variation and annual cycle characteristics of the frontal structure in the simulated *** on vertical cross-section data,the different frontal lifecycles of the two sides of the Zhujiang(Pearl)River Estuary are analyzed.

关键词： oceanic thermal fronts South China Sea seasonal dynamics

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Formation and control of disinfection byproducts and toxicity during reclaimed water chlorination： A review

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Journal of environmental Sciences 2017年第8期29卷 51-63页

作者： Ye Du Xiao-Tong Lv Qian-Yuan Wu Da-Yin Zhang Yu-Ting Zhou Lu Peng Hong-Ying Hu environmental Simulation and Pollution Control State key Joint laboratory State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC) School of Environment Tsinghua University Beijing 100084 China key laboratory of Microorganism application and Risk Control of Shenzhen Graduate School at Shenzhen Tsinghua University Shenzhen 518055 China Shenzhen environmental Science and New Energy technology Engineering laboratory Tsinghua-Berkeley Shenzhen Institute Shenzhen518055 China

Chlorination is essential to the safety of reclaimed water; however, this process leads to concern regarding the formation of disinfection byproducts（DBPs） and toxicity. This study reviewed the formation and control strategies for DBPs and toxicity in reclaimed water during *** regulated and emerging DBPs have been frequently detected in reclaimed water during chlorination at a higher level than those in drinking water, indicating they pose a greater risk to humans. Luminescent bacteria and Daphnia magna acute toxicity, anti-estrogenic activity and cytotoxicity generally increased after chlorination because of the formation of DBPs. Genotoxicity by umu-test and estrogenic activity were decreased after chlorination because of destruction of toxic chemicals. During chlorination, water quality significantly impacted changes in *** tended to attenuate toxicity changes by reacting with chlorine to form chloramine,while bromide tended to aggravate toxicity changes by forming hypobromous acid. During pretreatment by ozonation and coagulation, disinfection byproduct formation potential（DBPFP）and toxicity formation potential（TFP） occasionally increase, which is accompanied by DOC removal; thus, the decrease of DOC was limited to indicate the decrease of DBPFP and TFP. It is more important to eliminate the key fraction of precursors such as hydrophobic acid and hydrophilic neutrals. During chlorination, toxicities can increase with the increasing chlorine dose and contact time. To control the excessive toxicity formation, a relatively low chlorine dose and short contact time were required. Quenching chlorine residual with reductive reagents also effectively abated the formation of toxic compounds.

关键词： Reclaimed water Chlorination Disinfection byproducts Toxicity Precursor

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Mechanisms of atmospheric neutron-induced single event upsets in nanometric SOI and bulk SRAM devices based on experiment-verified simulation tool

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Chinese Physics B 2018年第6期27卷 336-340页

作者： Zhi-Feng Lei Zhan-Gang Zhang Yun-Fei En Yun Huang key laboratory of Low Dimensional Materials ＆ application technology of Ministry of Education Xiangtan University Xiangtan 411100 China Science and technology on Reliability Physics and application of Electronic Component laboratory China Electronic Product Reliability and Environmental Testing Research Institute Guangzhou 510610 China

In this paper, a simulation tool named the neutron-induced single event effect predictive platform（NSEEP^2） is proposed to reveal the mechanism of atmospheric neutron-induced single event effect（SEE） in an electronic device, based on heavy-ion data and Monte-Carlo neutron transport simulation. The detailed metallization architecture and sensitive volume topology of a nanometric static random access memory（SRAM） device can be considered to calculate the real-time soft error rate（RTSER） in the applied environment accurately. The validity of this tool is verified by real-time experimental results. In addition, based on the NSEEP^2, RTSERs of 90 nm–32 nm silicon on insulator（SOI） and bulk SRAM device under various ambient conditions are predicted and analyzed to evaluate the neutron SEE sensitivity and reveal the underlying mechanism. It is found that as the feature size shrinks, the change trends of neutron SEE sensitivity of bulk and SOI technologies are opposite, which can be attributed to the different MBU performances. The RTSER of bulk technology is always 2.8–64 times higher than that of SOI technology, depending on the technology node, solar activity, and flight height.

关键词： atmospheric neutron single event effects soft error rate Monte-Carlo simulation

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Attached cultivation of Scenedesmus ***1 on selected solids and the effect of surface properties on attachment

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Frontiers of environmental Science & Engineering 2019年第4期13卷 113-121页

作者： Hong-Ying Hu Tian-Yuan Zhang Xiao-Xiong Wang Yinhu Wu Guo-Hua Dao environmental Simulation and Pollution Control State key Joint laboratory State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (MARC)School of EnvironmentTsinghua UniversityBeijing 100084China Shenzhen environmental Science and New Energy technology Engineering laboratory Tsinghua-Berkeley Shenzhen InstituteShenzhen 518055China

Attached cultivation systems in the literature do not present a methodology to screen materials for microalgal growth. Hence, a method is needed to find suitable materials for attached cultivation that may enhance attachment of microalgae. In this paper, we have tested seven materials culturing Scenedesmus sp. LX1 (S. sp. LX1)to evaluate the attachment of microalgae on the material surface, its growth in suspension phase and the properties of the materials. Two materials showed attachment of S. sp. LX1, polyurethane foam and loofah sponge, and allowed microalgae to grow both in the surface of the material and suspended phase. Polyurethane foam proved to be a good material for attachment of S. sp. LX1 and the amount of attached microalgae obtained was 51.73 mg/L when adding 100 pieces/L. SEM images showed that the surface and the pore size of the materials affected the attachment of the microalgae, increasing its attachment in scaffold-like materials. Furthermore, the hydrophilic and hydrophobic properties of the materials also affected the attachment of microalgae. This research can be used as a methodology to search for the assessment of a material suitable for attachment of microalgae.

关键词： Attached cultivation Microalgae Material properties Polyurethane Scenedesmus

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