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Effect of three-electrode plasma synthetic jet actuator on shock wave control

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Science China(Technological Sciences) 2017年第1期60卷 146-152页

作者： ZHOU Yan xia ZhiXun luo ZhenBing WANG Lin Science and Technology on Scramjet Laboratory National University of Defense Technology Changsha 410073 China

A three-electrode high-energy plasma synthetic jet(PSJ) actuator was used for shock wave control. This actuator is an enhanced version of the two-electrode actuator as a high-voltage trigger electrode is added to increase the cavity volume and the input energy while retaining a relatively low disruptive voltage. The electrical properties were studied using current-voltage measurements, and the energy consumption was calculated. To assess the jet strength, the penetration of PSJ was compared with empirical values, and the results show that the momentum flux ratio of PSJ for a capacitance of 0.96, 1.6, and 3 μF was approximately equal to 0.6, 1.0, and 1.3, respectively. The interaction of PSJ with shock waves was acquired using high-speed shadowgraph imaging. The shock was generated by a 25° compression ramp in Mach 2 flow, and PSJ actuator was placed up-stream of the compression ramp. Under the action of PSJ, the strength of the shock was notably weakened, and the near-wall part of the shock was entirely eliminated. The results show the good control effect of the three-electrode high-energy PSJ in high-speed flow.

关键词： plasma synthetic jet three-electrode shock wave active flow control

Multi-Factor Intensity Estimation for Tropical Cyclones in the Western North Pacific Based on the Deviation Angle Variance Technique

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Journal of Meteorological Research 2020年第5期34卷 1038-1051页

作者： Wei ZHONG Meng YUAN Hexin YE xia luo College of Meteorology and Oceanology National University of Defense TechnologyNanjing 211101 Submarine College of Navy Qingdao 266199

In this paper, the infrared cloud images from Fengyun series geostationary satellites and the best track data from the China Meteorological Administration(CMA-BST) in 2015–2017 are used to investigate the effects of two multifactor models, generalized linear model(GLM) and long short-term memory(LSTM) model, for tropical cyclone(TC) intensity estimation based on the deviation angle variance(DAV) technique. For comparison, the typical singlefactor Sigmoid function model(SFM) with the map minimum value of DAV is also used to produce TC intensity estimation. Sensitivity experiments regarding the DAV calculation radius and different training data groups are conducted, and the estimation precision and optimum calculation radius for DAV in the western North Pacific(WNP) are analyzed. The results show that the root-mean-square-error(RMSE) of the single-factor SFM is 8.79–13.91 m s^-1 by using the individual years as test sets and the remaining two years as training sets with the optimum calculation radius of 550 km. However, after selecting and using the high-correlation multiple factors from the same test and training data, the RMSEs of GLM and LSTM models decrease to 5.93–8.68 and 4.99–7.00 m s^-1 respectively, with their own optimum calculation radii of 350 and 400 km. All the sensitivity experiments indicate that the SFM results are significantly influenced by the DAV calculation radius and characteristics of the training set data, while the results of multi-factor models appear more stable. Furthermore, the multi-factor models reduce the optimum radius within the process of DAV calculation and improve the precision of TC intensity estimation in the WNP, which can be chosen as an effective approach for TC intensity estimation in marine areas.

关键词： deviation angle variance(DAV)technique tropical cyclone(TC) intensity estimation

The electrochemical behavior of N-n-undecy1-N＇-（sodium-p- amino-benzenesulfonate） thiourea and its interaction with bovine serum albumin

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Chinese Chemical Letters 2008年第5期19卷 581-584页

作者： Hong xia luo Yang Du Zhi Xin Guo Department of Chemistry Renmin University of China Beijing 100872 China

In pH 5.5 phosphate buffer solution, N-n-undecyl-N＇-（sodium-p-amino-benzenesulfonate） thiourea （UPT） produced a pair of redox peaks on the bare glassy carbon electrode. At the multi-walled carbon nanotube （MWNT） modified electrode, the electrochemical behavior of UPT enhanced greatly. In the presence of bovine serum albumin （BSA）, the peak currents of UPT decreased linearly due to the formation of a super-molecular complex. This method was successfully applied to the determination of BSA in a bovine serum sample.

关键词： N-n-Undecyl-N'-(sodium-p-amino-benzenesulfonate) thiourea Carbon nanotube Electrocatalysis Bovine serum albumin

Reversible electrochemistry of DNA on multi-walled carbon nanotube modified electrode

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Chinese Chemical Letters 2007年第7期18卷 861-864页

作者： Hong xia luo Zhi Xin Guo Nan He Department of Chemistry Renmin University of China Beijing 100872 China

Calf thymus DNA was electrochemically oxidized at a multi-walled carbon nanotube modified electrode. The potentials for DNA oxidation at pH 7.0 were 0.71 and 0.81 V versus SCE, corresponding to the oxidation of guanine and adenine residues,respectively. The initial 6e-oxidation of adenine, observed in the first scan, resulted a quasi-reversible 2e-redox process of the oxidation product in the following scans.

关键词： Carbon nanotube DNA Cyclic voltammetry Reversible

Remote Impact of Blocking Highs on the Sudden Track Reversal of Tropical Cyclones

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Advances in Atmospheric Sciences 2015年第11期32卷 1517-1532页

作者： luo xia FEI Jianfang HUANG xiaogang CHENG xiaoping YU Kun College of Meteorology and Oceanography PLA University of Science and Technology

Previous work showed that some tropical cyclones （TCs） in the western Pacific Ocean undergo sudden track reversal, and the onset, maintenance and decay of blocking highs （BHs） coexisted with 19 of the studied TCs with sudden track reversal. In these cases, the phase relations between the BH, the continental high （CH）, the subtropical high （SH） and the suddenly reversed TCs could be classified into types A, B, C and D. Types C and D were the focal point of this follow-up study, in which Typhoon Pabuk （2007） and Lupit （2009） were employed to conduct numerical simulations. The results showed that the reversed tracks of Pabuk （2007） and Lupit （2009） could have been affected by the BH, particularly in terms of the turning location and the trend of movement after turning. Specifically, the two main features for Pabuk （2007） in the BH perturbations were the deflection of its turning point and a distinct anticlockwise rotation. Lupit （2009） deviated to the southwest and finally made landfall in the Philippines, or experienced further eastward movement, in the perturbed BH. The impact mechanisms can be attributed to the change in the vorticity field transported from the BH, leading to an intensity variation of midlatitude systems. BHs may have a positive feedback effect on the strength of the westerly trough （TR）, as indicated by a weakened and strengthened TR corresponding to negative and positive BH perturbations, respectively.

关键词： blocking high tropical cyclone suddenly reversed track numerical simulation

Energy transfer,luminescence properties,and thermal stability of color tunable barium pyrophosphate phosphors

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Chinese Physics B 2020年第6期29卷 153-158页

作者： Meng-Jiao Xu Su-xia Li Chen-Chen Ji Wan-xia luo Lu-xiang Wang Key Laboratory of Energy Materials Chemistry of Ministry of Education Key Laboratory of Advanced Functional Materials of Xingjiang Uygur Autonomous RegionInstitute of Applied ChemistryXinjiang UniversityUrumqi 830046China College of Chemistry and Chemical Engineering Xinjiang UniversityUrumqi 830046China

A series of barium pyrophosphate Ba2P2O7(BPO)phosphors doped with Ce3+or Tb3+ions is synthesized via a co-precipitation method under reducing *** phase structures,photoluminescence(PL)properties,and thermal stabilities of the samples are characterized by using powder x-ray diffraction(PXRD)and PL *** emission colors of samples can be tuned from blue(0.1544,0.0310)to green(0.2302,0.4229)by changing the doping concentrations of Tb3+under ultraviolet *** energy transfer mechanism between Ce3+and Tb3+in the BPO is dipole–dipole interaction with a critical distance of 25.86°A and an energy transfer efficiency of about 85%,which are determined through the PL spectrum and the decay ***,the Ce3+/Tb3+co-doped sample has good thermal stability for temperature quenching,and the emission intensity at 423 K is maintained at 95%measured at 298 *** above results show that the BPO:Ce3+,Tb3+can serve as a promising candidate of green emitting phosphor for solid-state lighting.

关键词： phosphor photoluminescence energy transfer thermal stability

Changes in the Chemical Components of Light Crude Oil During Simulated Short Term Weathering

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Journal of Ocean University of China 2007年第3期6卷 231-236页

作者： MA Qimin luo xia YU Zhigang College of Environmental Science and Engineering Ocean University of China Qingdao 266100 P. R. China College of Chemistry and Chemical Engineering Ocean University of China Qingdao 266100 P. R. China

To unambiguously identify spilled oils and to link them to the known sources are extremely important in settling ques-tions of environmental impact and legal liability. The fate and behavior of spilled oils in the environment depend on a number of physicochemical and biological factors. This paper presents the results regarding changes in chemical composition of light crude oil during simulated short-term weathering based on natural environmental conditions. The results show that the saturated hydrocarbons of the light crude oil mainly distribute between n-C8 and n-C23 and the most abundant n-alkanes are found in the n-C10 to n-C16. The main chemical components of the light crude oil are n-alkanes and isoprenoids. The aromatic compounds are subordinate chemical components. Under the conditions of the weathering simulation experiment,n-alkanes less than n-C12,toluene and 1,3-dimethyl ben-zene are lost after 1 d weathering,the n-C13,n-C14,naphthalene and 2-methyl-naphthalene are lost on the fifth day of weathering,and n-C15 alkane components show certain weatherproof capability. The ratios n-C17/pristane and n-C18/phytane are unaltered and can be used to identify the source of the light crude oil during the first 8 d of weathering. After 21 d,the ratio pristine/phytane can not pro-vide much information on the source of the spilled light crude oil. Triterpanes(m/z 191) as biomarker compounds of light crude oil are more valuable.

关键词： light crude oil weathering GC/MS oil fingerprints RNA thermosensor

A new member of the calix[4]crown family:Facile synthesis and characterization of a calix[4]crown-9 cone conformer

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Chinese Chemical Letters 2009年第2期20卷 143-146页

作者： Hao Hui Zhou xian Mei Shang Zhi luo Yu xiang xia Jun luo Guang Ya xiang Tongji School of Pharmacy Huazhong University of Science and Technology Wuhan 430030 China

25,27-Dipropoxy-p-tert-butylcalix[4]crown-9 cone conformer 5 was readily synthesized via an intramolecular cyclization strategy in good yields. The structures of all the new compounds involved were confirmed by NMR, E... 详细信息

关键词： Calixcrown-9 Cone conformation Synthesis Intramolecular cyclization

Statistical Characteristics and Mechanistic Analysis of Suddenly Reversed Tropical Cyclones over the Western North Pacific Ocean

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Advances in Atmospheric Sciences 2015年第4期32卷 565-576页

作者： luo xia FEI Jianfang HUANG xiaogang CHENG xiaoping DING Juli HE Yiqiang College of Meteorology and Oceanography PLA University of Science and Technology Beijing Aerospace Control Center

Based on best track data of tropical cyclones（TCs） from the Japan Meteorological Agency, the characteristics of suddenly reversed TCs（SRTCs）, which have turning angles usually approaching 180°, are statistically analyzed from 1949 to 2011 over the western North Pacific Ocean. The typical large-scale circulation patterns of SRTCs are investigated using reanalysis data and dynamical composite analysis. Results show that turnings mainly occur in low latitudes between 10°N and 20°N,and mainly west of 135°E. The majority of SRTCs reach their peak intensity at, or slightly before, the turning time and subsequently decrease at some variable rate. Specifically, SRTCs are divided into four types, each containing two groups（*** groups in total） in terms of the moving-direction changes. The moving speed of all SRTC types except the south–north type decreases to its lowest during the 24 h, corresponding to a significant reduction in the primary steering *** to the analysis of the 13 typical flow patterns found in this study, we suggest that sudden track changes are caused by the reversal steering flow. The original balance of the background flow patterns are broken up by new systems, e.g. binary TCs or dispersion-induced anticyclones. Additionally, sudden track changes are often due to double ridge variations of the subtropical high or weakened/strengthened high pressure in the east and west, respectively.

关键词： tropical cyclone suddenly reversed turning statistical analysis steering flow