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EXPERIMENT STUDY ON SEDIMENT INCIPIENCE IN BACKWARD-FACING STEP FLOW

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Journal of Hydrodynamics 2007年第2期19卷 173-179页

作者： LIU chun-rong Huhe Aode tao Long-bin Department of-Engineering Mechanics Hunan University Changsha 410082 China Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China School of Engineering Griffith University PMB50 GCMC Qld9726 Australia

Flow over a backward-facing step was studied to investigate the effect of large-scale vortex structures on sediment incipience. The transient flow velocity field at the downstream of the backward-facing step was obtained using the technique of Particle Tracking Velocimetry （PTV）. The optical amplification technique was employed to measure the instantaneous flow velocities near the bed and the instantaneous bed shear stress was given. The experimental observations revealed a new insight into the oscillation of the large-scale structure and the three-dimensional characteristics of the flow. In particular, very high turbulence intensity, instantaneous horizontal velocity near the bed and the bed shear stress near the reattachment point were observed. The sediment incipient probability obtained from the sequent images of sediment particles near the bed indicates that the critical instantaneous shear stress of the sediment incipience is independent of flow conditions.

关键词： backward-facing step flow coherent structure,sediment incipience Particle Tracking Velocimetry (PTV)

Photolysis of chlortetracycline in aqueous solution:Kinetics,toxicity and products

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Journal of Environmental Sciences 2012年第2期24卷 254-260页

作者： Yong Chen Hua Li Zongping Wang tao tao Dongbin Wei chun Hu State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China School of Environmental Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China.

The aqueous photodegradation of the widely used antibiotic chlortetracycline（CTC） was investigated under simulated *** quantum yield of photodegradation increased from 3.3 × 10-4 to 8.5 × 10-3 within the pH range of 6.0 to *** presence of Ca2＋,Fe3＋,and NO3-enhanced the photodegradation of CTC,whereas Mg2＋,Mn2＋,and Zn2＋ inhibited the degradation with the order Mn2＋ Zn2＋ Mg2＋ at pH *** monovalent cations（Na＋ and K＋） had negligible effect on the photolysis of *** acid（FA） decreased the photodegradation of CTC due to light screening *** peroxide（H2O2） was formed concurrently with direct photodegradation of *** generation rate of H2O2 increased from 0.027 to 0.086 μmol/（***） when the pH ranged from 6.0 to *** CTC solution was about three-fold more toxic to the Photobacterium phosphoreum bacteria after irradiation,suggesting that the photoproducts and H2O2 formed in the CTC solution exhibited high risk on the *** LC-ESI（＋）-MS,the photoproducts of CTC were *** direct photodegradation of CTC was involved in hydroxylation and N-demethyl/dedismethyl *** main photoproducts included the iso-CTC analog containing hydroxyl groups（m/z 511.4 and 495.4）,and the N-demethyl/dedismethyl products of the photoproduct m/z 495.4（m/z 481.3 and 467.4）.In addition,the photochemical dechlorination of CTC led to tetracycline（m/z 445.5）.

关键词： chlortetracycline direct photodegradation phototoxicity photoproducts

An air cavity method for increasing the underwater acoustic targets strength of corner reflector

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Defence Technology（防务技术） 2020年第2期16卷 493-501页

作者： Yi luo Xin Chen Da-wei Xiao Wu-di Wen tao-tao Xie Dept.of Weaponry Eng Naval University of EngineeringWuhan 430033China

In order to improve the underwater acoustic target strength of comer reflectors,according to the principle of acoustic impedance mismatch of the boundary layer,the method of using air cavity to increase the underwater acoustic target strength of corner reflectors is *** acoustic reflection coefficients of underwater air layer and single layer metal sheet are calculated and *** results show that the reflection coefficient of single layer metal sheet is greatly affected by frequency and incidence angle,and the reflection coefficient of air layer in water is large and little affected by frequency and incidence *** this basis,a new kind of airfilled cavity corner reflector is *** acoustic scattering characteristics of underwater airfilled cavity comer reflector are calculated cumulatively,and the results are compared with the monolayer metal sheet corner *** simulation results show that the acoustic reflection effect of the airfilled cavity corner reflector is *** order to verify the correctness of the method,the test was carried out in the silencing *** experimental results show that the simulation results are in good agreement with the experimental results,and the airfilled cavity can improve on acoustic reflection performance of the underwater corner reflector.

关键词： Underwater corner reflector Acoustic target strength Air cavity Acoustic impedance mismatch

Aerosol flotation of low-grade refractory molybdenum ores

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International Journal of Minerals,Metallurgy and Materials 2012年第12期19卷 1077-1082页

作者： tao Xu chun-bao Sun Key Laboratory of the Ministry of Education of China for High-Efficient Mining and Safety of Metal Mines University of Science and Technology BeijingBeijing 100083China

The characteristics of aerosol flotation, which include the effect of the concentration and particle size of kerosene aerosol on the molybdenum （Mo） flotation index and the effect of kerosene aerosol dosing method on the kerosene dosage and flotation time, were studied in the flotation of low-grade refractory molybdenum ores using kerosene aerosol. The results revealed that the particle size and concentration of kerosene aerosol had little effect on the Mo grade but had significant effect on the Mo recovery. A smaller particle size and a lower con-centration of kerosene aerosol were beneficial to the Mo aerosol flotation. For the received Mo ore samples, the optimized particle size of kerosene aerosol was 0.3-2 μm and the optimized aerosol concentration was 14 mg/L. The compressed air atomizer had a more uniform dis-tribution of aerosol particles than the ultrasonic atomizer, and the aerosol concentration was controlled easily, so the compressed air atomizer was more suitable for the research of aerosol flotation. Compared with conventional flotation in which kerosene was directly added into the ore pulp, the flotation time was reduced by ~30%, and the dosage was decreased by ~20% in aerosol flotation, while the Mo flotation index was similar.

关键词： molybdenum ore treatment flotation kerosene aerosols particle size

Tp53 gene mediates distinct dopaminergic neuronal damage in different dopaminergic neurotoxicant models

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Neural Regeneration Research 2017年第9期12卷 1413-1417页

作者： tao Lu Paul Kim Yu luo Department of Neurological Surgery Case Western Reserve University Medical Faculty Kunming University of Science and Technology

Tp53, a stress response gene, is involved in diverse cell death pathways and its activation is implicated in the pathogenesis of Parkinson＇s disease. However, whether the neuronal Tp53 protein plays a direct role in regulating dopaminergic （DA） neuronal cell death or neuronal terminal damage in different neurotoxicant models is unknown. In our recent studies, in contrast to the global inhibition of Tp53 function by phar- macological inhibitors and in traditional Tp53 knock-out mice, we examined the effects of DA-specific Tp53 gene deletion after 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and methamphetamine exposure. Our data suggests that the Tp53 gene might be involved in both neuronal apoptosis and neuronal termi- nal damage caused by different neurotoxicants. Additional results from other studies also suggest that as a master regulator of many pathways that regulate apoptosis and synaptic terminal damage, it is possible that Tp53 may function as a signaling hub to integrate different signaling pathways to mediate distinctive target pathways. Tp53 protein as a signaling hub might be able to evaluate the microenvironment of neurons, assess the forms and severities of injury incurred, and determine whether apoptotic cell death or neuro- nal terminal degeneration occurs. Identification of the precise mechanisms activated in distinct neuronal damage caused by different forms and severities of injuries might allow for development of specific Tp53 inhibitors or ways to modulate distinct downstream target pathways involved.

关键词： Parkinson's disease Tp53 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine neurotoxicity apoptosis methamphetamine

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疲劳评价与食源性抗运动疲劳成分研究进展

食品工业科技 2025年第2期46卷 394-402页

作者：李梦民刘滔罗婷王豆欧昌荣杨桂玲宁波大学食品科学与工程学院省部共建农产品质量安全危害因子与风险防控国家重点实验室浙江省农业科学院农产品质量安全与营养研究所省部共建农产品质量安全危害因子与风险防控国家重点实验室湘湖实验室农业农村部农业转基因生物朔源重点实验室

运动性疲劳会导致机体产生体力匮乏、注意力下降、工作能力降低等现象，而食源性抗运动疲劳活性成分来源广泛并具有显著缓解效果，在功能食品开发、医疗保健应用等领域具备广阔发展前景。本文首先综述了机体内乳酸、糖原、乳酸脱氢酶、... 详细信息

运动性疲劳会导致机体产生体力匮乏、注意力下降、工作能力降低等现象，而食源性抗运动疲劳活性成分来源广泛并具有显著缓解效果，在功能食品开发、医疗保健应用等领域具备广阔发展前景。本文首先综述了机体内乳酸、糖原、乳酸脱氢酶、尿素氮等与运动性疲劳程度紧密相关的评价指标，其次，基于运动性疲劳的主要缓解途径包括提高机体能量储备、清除代谢产物、维持氧化还原平衡、抑制炎症反应、缓解神经中枢疲劳等方式，本文罗列了具有显著抗运动疲劳潜力的食源性活性成分，并总结了不同成分复合缓解疲劳的相互作用，以期为食源性复合抗疲劳功能食品和保健品的开发利用提供理论参考。

关键词：运动性疲劳食源性疲劳指标抗疲劳途径相互作用

来源：博看期刊

Coating of microbially produced calcium carbonate onto stone materials

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Science China(Technological Sciences) 2015年第2期58卷 266-272页

作者： ZHU Wen Kun MU tao ZHANG You Kui DUAN tao luo Xue Gang Engineering Research Center of Biomass Materials Ministry of Education Southwest University of Science and Technology China Academy of Engineering Physics Joint Laboratory for Extreme Conditions Matter Properties Southwest University of Science and Technology and Research Center of Laser FusionCAEP

The coatings of microorganism-induced calcium carbonate onto the stone surface carried out by using both of the immersion method and coating method were investigated. Various analysis and testing techniques such as scanning electron micrograph （SEM） and X-ray diffraction （XRD） were used to characterize the deposited mineral layer. The adhesive property, acid re- sistance, frost resistance, light and aging resistance, water adsorption and permeability were investigated in detail. The results showed that both immersion method and coating method could produce calcium carbonate granules with sizes ranging from 1 to 10 pm and form a layer of dense mineralization membrane which is about 50 to 100 pm thick. Immersion method was more efficient than coating method. The large cohesive force between calcium carbonate layer and stone materials could improve the acid rain resistance as well as excellent heat tolerance, frost resistance and light aging resistance. The coating process could not only help the stone materials maintain its original permeability with the aid of calcium carbonate layers but also improve the penetration resistance significantly. Therefore, this type of technology shows a great potential in the protection of stone relics.

关键词： microorganism microbially induced deposited-layer stone materials

Dynamic subcarrier and power allocation based on cooperative game theory in symmetric cooperative OFDMA networks

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The Journal of China Universities of Posts and Telecommunications 2011年第2期18卷 9-16页

作者： LIU Wei luo tao YUE Guang-xin Key Laboratory of Universal Wireless Communication Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

In order to improve the efficiency and fairness of radio resource utilization,a scheme of dynamic cooperative subcarrier and power allocation based on Nash bargaining solution（NBS-DCSPA） is proposed in the uplink of a three-node symmetric cooperative orthogonal frequency division multiple access（OFDMA） *** the proposed NBS-DCSPA scheme,resource allocation problem is formulated as a two-person subcarrier and power allocation bargaining game（SPABG） to maximize the system utility,under the constraints of each user＇s maximal power and minimal rate,while considering the fairness between the two ***,the equivalent direct channel gain of the relay link is introduced to decide the transmission mode of each ***,all subcarriers can be dynamically allocated to the two users in terms of their selected transmission *** that,the adaptive power allocation scheme combined with dynamic subcarrier allocation is optimized according to ***,computer simulation is conducted to show the efficiency and fairness performance of the proposed NBS-DCSPA scheme.

关键词： cooperative relay OFDMA radio resource allocation NBS fairness

Key machining characteristics in ultrasonic vibration cutting of single crystal silicon for micro grooves

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Advances in Manufacturing 2019年第3期7卷 303-314页

作者： Jun-Yun Chen Tian-Ye Jin Xi-chun luo College of Vehicles and Energy Yanshan UniversityQinhuangdao 066004HebeiPeople's Republic of China Department of Design Manufacture and Engineering ManagementFaculty of EngineeringUniversity of StrathclydeGlasgow G11XJUK Center for Precision Engineering Harbin Institute of TechnologyHarbin 150001People's Republic of China

Structured complex silicon components have been widely used in solar cells,biomedical engineering and other industrial *** silicon is a typical brittle material,ultrasonic vibration cutting(UVC)is a promising method to achieve better cutting performance than conventional ***-frequency ID UVC possesses higher nominal cutting speed and material removal rate than many 2D/3D UVC systems,and thus,it has great development potential in industrial applications of structured silicon ***,few researchers have applied ID UVC to the cutting of structured silicon surfaces,since its main drawback is tool marks imprinted by the vibration on machined *** this study,to uncover the key machining characteristics under the condition of ID UVC,a series of tests involving diamond cutting grooves were first performed on the silicon *** machined surface and chips were subsequently measured and analyzed to evaluate the critical undeformed chip thickness,surface characteristics,and chip *** the main drawback of ID UVC,a novel theoretical model was developed for predicting the length of tool marks and evaluating the impact of tool marks on the surface *** results demonstrated that the critical undeformed chip thickness of silicon reached 1030 nm under a certain vibration amplitude and that an array of micro grooves was generated at the plastic region with a surface roughness(7?a)as low as 1.11 ***,the micro topography of the continuous chips exhibited discontinuous clusters of lines with diameters of dozens of nanometers,only composed of *** novel theoretical model was able to predict the length of tool marks with low ***,the impact of tool marks on the surface finish can be reduced and even eliminated with help of the model.

关键词： Ultrasonic vibration cutting(UVC) Single crystal Silicon Micro groove Chip Tool vibration mark