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Time-frequency analysis of internal waves generated by a towed and self-propelled submerged body model

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Journal of Hydrodynamics 2023年第6期35卷 1191-1207页

作者： Yu-hang Li Fei-yu Chen Li-ping qin Ke Chen Yun-xiang you Zhengzhou Electromechanical Engineering Research Institute Zhengzhou450015China Henan Key Laboratory of Underwater Intelligence Equipment Zhengzhou450015China State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai200240China Yazhou Bay Institute of Deepsea Technology Shanghai Jiao Tong UniversityShanghai200240China

The spectrogram,based on a short-time Fourier transform,can visualize the time-dependent frequency spectrum of waves and is easy to *** time-frequency analysis method provides crucial information about waves generated by moving vessels and has been utilized to analyze Kelvin ship waves and internal *** further study the internal waves induced by a submerged body,an experiment is conducted for the towed and self-propelled SUBOFF model in a stratified *** internal wave elevation signals are captured using electronic conductivity *** with the calculation results of theoretical model,the high-frequency component of internal waves is *** high-frequency component has the exact same characteristics in both the towed and self-propelled model experiment and is consistent with the theoretical results for all Froude ***,this component is composed mainly of lee *** spectral characteristics identification,a low-frequency component is discovered in the spectrogram in addition to the lee wave *** intensity of the low-frequency component is tightly related to the vortex structure behind the submerged *** vortex structure depends on the net momentum imparted by the submerged ***,this component is composed mainly of wake waves induced by the vortex structure.

关键词： Stratified fluid internal waves submerged body experimental study time-frequency analysis

Dietary seaweed-derived polysaccharides improve growth performance of weaned pigs through maintaining intestinal barrier function and modulating gut microbial populations

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Journal of Animal Science and Biotechnology 2021年第3期12卷 1184-1195页

作者： Tiande Zou Jin Yang Xiaobo Guo qin He Zirui Wang Jinming you Jiangxi Province Key Laboratory of Animal Nutrition College of Animal Science and TechnologyJiangxi Agricultural UniversityNanchang 330045JiangxiChina Jiangxi Province Key Innovation Center for Industry-Education Integration of High-Quality and Safety Livestock Production Nanchang 330045China

Background:Seaweed-derived polysaccharides(SDP)represent an attractive source of prebiotic nutraceuticals for the food and animal husbandry ***,the mechanism by which SDP from Enteromorpha mediates pig growth are not fully *** study aimed to investigate how SDP supplementation influences the growth performance and intestinal health in weaned ***:In Exp.1,240 weaned pigs were randomly assigned to four dietary treatments and fed with a basal diet or a basal diet containing 200,400 or 800 mg/kg SDP,respectively,in a 21-day *** on the 400 or 800 mg/kg SDP-supplemented group had greater ADG and lower F/G ratio than those on the control group(P<0.05).In Exp.2,20 male weaned pigs were randomly assigned to two treatments and fed with a basal diet(CON group)or a basal diet supplemented with 400 mg/kg SDP(the optimum does from Exp.1),in a 21-day *** fed the SDP diet had greater ADG,the concentrations of serum IL-6 and TNF-αand the activities of glutathione peroxidase,superoxide dismutase and catalase(P<0.05),and lower F/G,diarrhea rate,as well as serum D-lactate concentrations and diamine oxidase activity(P<0.05).Moreover,dietary SDP supplementation enhanced secretory immunoglobulin A content,villus height and villous height:crypt depth ratio in small intestine,as well as the lactase and maltase activities in jejunum mucosa(P<0.05).SDP supplementation elevated the mRNA levels of inflammatory responserelated genes(IL-6,TNF-α,TLR4,TLR6 and MyD88),and the mRNA and protein levels of ZO-1,claudin-1 and occludin in jejunum mucosa(P<0.05).Importantly,SDP not only increased the Lactobacillus population but also reduced the Escherichia coli population in cecum(P<0.05).Furthermore,SDP increased acetic acid and butyric acid concentrations in cecum(P<0.05).Conclusions:These results not only suggest a beneficial effect of SDP on growth performance and intestinal barrier functions,but also offer potential mechanisms behind SDP-facilitated int

关键词： Intestinal health Microflora Pigs Seaweed-derived polysaccharides

Liquefaction susceptibility and deformation characteristics of saturated coral sandy soils subjected to cyclic loadings-a critical review

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 261-296页

作者： Chen Guoxing qin you Ma Weijia Liang Ke Wu Qi C.Hsein Juang Institute of Geotechnical Engineering Nanjing Tech UniversityNanjing 210009China Civil Engineering and Earthquake Disaster Prevention Center of Jiangsu Province Nanjing 210009China School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China College of Civil Aviation Nanjing University of Aeronautics and AstronauticsNanjing 210016China Glenn Department of Civil Engineering Clemson UniversityClemsonSC 29634USA

Coral sandy soils widely exist in coral island reefs and seashores in tropical and subtropical *** to the unique marine depositional environment of coral sandy soils,the engineering characteristics and responses of these soils subjected to monotonic and cyclic loadings have been a subject of intense interest among the geotechnical and earthquake engineering *** paper critically reviews the progress of experimental investigations on the undrained behavior of coral sandy soils under monotonic and cyclic loadings over the last three *** focus of coverage includes the contractive-dilative behavior,the pattern of excess pore-water pressure(EPWP)generation and the liquefaction mechanism and liquefaction resistance,the small-strain shear modulus and strain-dependent shear modulus and damping,the cyclic softening feature,and the anisotropic characteristics of undrained responses of saturated coral sandy *** particular,the advances made in the past decades are reviewed from the following aspects:(1)the characterization of factors that impact the mechanism and patterns of EPWP build-up;(2)the identification of liquefaction triggering in terms of the apparent viscosity and the average flow coefficient;(3)the establishment of the invariable form of strain-based,stress-based,or energy-based EPWP ratio formulas and the unique relationship between the new proxy of liquefaction resistance and the number of cycles required to reach liquefaction;(4)the establishment of the invariable form of the predictive formulas of small strain modulus and strain-dependent shear modulus;and(5)the investigation on the effects of stress-induced anisotropy on liquefaction susceptibility and dynamic deformation *** gained through the critical review of these advances in the past decades offer a perspective for future research to further resolve the fundamental issues concerning the liquefaction mechanism and responses of coral sandy sites subjecte

关键词： liquefaction susceptibility dynamic deformation characteristics coral sandy soil cyclic loading review and prospect

Pho to luminescence and Photoluminescence Excitation of Si Aerogels Prepared by Supercritical Drying

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Chinese Physics Letters 1996年第1期13卷 62-64页

作者： GUO Guo-lin XU Dong-sheng YAO guang-qing TANG you-qi ZHANG Li-dong LIN Jun MA Shu-yi DUAN Jia-qi ZHANG Bo-rui qin Guo-gang Department of Chemistry Peking UniversityBeijing 100871 Department of Physics Peking UniversityBeijing 100871

Si aerogel,the porous silicon with ultra high porosity,has been prepared by the technique of anodization followed by supercritical *** photoluminescence,photoluminescence excitation and morphological features exhibit novel characteristics from those of the conventionally anodized porous *** observed the differences between the Si aerogels made&om(100)and(111)crystalline Si.

关键词： porous excitation porosity

Mechanical Property of M40J_f/5A06Al Composite at Elevated Temperatures

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Acta Metallurgica Sinica(English Letters) 2015年第9期28卷 1175-1182页

作者： Da-guang Li Guo-qin Chen Long-Tao Jiang Xiu Lin Gao-Hui Wu School of Materials Science and Engineering Harbin Institute of Technology State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology Heilongjiang Academy of Industrial Technology

In this work, aluminum alloy with a high concentration of magnesium （5A06） was reinforced with 55 vol% unidirectional ultra-high modulus and highly graphitized carbon fiber （M40J） using pressure infiltration method. The effect of temperature on the bending strength of the Cf/A1 composites was investigated from room temperature to 500 ℃. The experimental results showed that the strength of M40Jf/5A06A1 composites was not affected by temperature from room temperature to 200 ℃. The bending strength of the composite at 300 ℃ was decreased by 30% compared with that at room temperature. In order to evaluate the extent of interface weakening, the length of fiber pullout was measured. The results showed that the pullout length reached the maximum at 300 and 500 ℃, which indicated weak interface at the corre- sponding temperature. The DSC curve presented obvious heat absorption peak at around 300 ℃, which may be attributed to the dissolution of the interfacial product （A13Mg2） phases at the C/A1 interface. The bending fracture surfaces of the composites after three-point bending tests were observed by SEM, plastic-viscous flow of the matrix were observed at the samples tested at 500 ℃. The predominant mechanisms for high-temperature damage of M40Jf/5A06A1 composites are matrix softening caused by dislocation recovery and interface weakening caused by the dissolution of interfacial products.

关键词： Carbon fiber Aluminum Metal matrix composites High-temperature properties Fiberpullout length

Transjugular intrahepatic portosystemic shunt for the prevention of recurrent esophageal variceal bleeding in patients with cavernous transformation of portal vein

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Hepatobiliary & Pancreatic Diseases International 2018年第6期17卷 517-523页

作者： Zhao-Peng Li Sui-Sui Wang guang-Chuan Wang guang-Jun Huang Jing-qin Cao Chun-qing Zhang Department of Gastroenterology Shandong Provincial Hospital Affiliated to Shandong UniversityJinan 250021China Department of Interventional Radiology Jining No.1 People’s HospitalJining 272011China Department of Pediatrics The Affiliated Hospital of Jining Medical CollegeJining 272000China

Background: Treatment options for patients with cavernous transformation of portal vein(CTPV) are limited. This study aimed to evaluate the feasibility, efficacy and safety of transjugular intrahepatic portosystemic shunt(TIPS) to prevent recurrent esophageal variceal bleeding in patients with CTPV. Methods: We retrospectively analyzed 67 consecutive patients undergone TIPS from January 2011 to December 2016. All patients were diagnosed with CTPV. The indication for TIPS was a previous episode of variceal bleeding. The data on recurrent bleeding, stent patency, hepatic encephalopathy and survival were retrieved and analyzed. Results: TIPS procedure was successfully performed in 56 out of 67(83.6%) patients with CTPV. TIPS was performed via a transjugular approach alone( n = 15), a combined transjugular/transhepatic approach( n = 33) and a combined transjugular/transsplenic approach( n = 8). Mean portosystemic pressure gradient(PSG) decreased from 28.09 ± 7.28 mmHg to 17.53 ± 6.12 mmHg after TIPS( P < 0.01). The probability of the remaining free recurrent variceal bleeding was 87.0%. The probability of TIPS patency reached 81.5%. Hepatic encephalopathy occurrence was 27.8%, and survival rate was 88.9% until the end of follow-up. Four out of 11 patients who failed TIPS died, and 4 had recurrent bleeding. Conclusions: TIPS should be considered a safe and feasible alternative therapy to prevent recurrent esophageal variceal bleeding in patients with CTPV, and to achieve clinical improvement.

关键词： Cavernous transformation Portal vein Transjugular intrahepatic portosystemic shunt Variceal rebleeding Portal hypertension

Extraction and characterization of bound extracellular polymeric substances from cultured pure cyanobacterium(Microcystis wesenbergii)

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Journal of Environmental Sciences 2014年第8期26卷 1725-1732页

作者： Lizhen Liu Boqiang qin Yunlin Zhang guangwei Zhu guang Gao Qi Huang Xin Yao State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography & LimnologyChinese Academy of Sciences University of Chinese Academy of Sciences School of Environment and Planning Liaocheng University

Preliminary characterization of bound extracellular polymeric substances（bEPS） of cyanobacteria is crucial to obtain a better understanding of the formation mechanism of cyanobacterial bloom. However,the characterization of bEPS can be affected by extraction methods. Five sets（including the control） of bEPS from Microcystis extracted by different methods were characterized using three-dimensional excitation and emission matrix（3DEEM） fluorescence spectroscopy combined chemical spectrophotometry; and the characterization results of bEPS samples were further compared. The agents used for extraction were NaOH,pure water and phosphate buffered saline（PBS） containing cationic exchange resins,and hot water. Extraction methods affected the fluorescence signals and intensities in the bEPS. Five fluorescence peaks were observed in the excitation and emission matrix fluorescence spectra of bEPS samples. Two peaks（peaks T1 and T2） present in all extractions were identified as protein-like fluorophores,two（peaks A and C） as humic-like fluorophores,and one（peak E） as a fulvic-like *** these substances,the humic-like and fulvic-like fluorescences were only seen in the bEPS extracted with hot water. Also,NaOH solution extraction could result in strong fluorescence intensities compared to the other extraction methods. It was suggested that NaOH at pH 10.0 was the most appropriate method to extract bEPS from Microcystis. In addition,dialysis could affect the yields and characteristics of extracted bEPS during the determination process. These results will help us to explore the issues of cyanobacterial blooms.

关键词： Bound extracellular polymeric substances(bEPS) Extraction Fluorescence intensities Microcystis Three-dimensional excitation and emission matrix(3DEEM)

A Chandra study of the massive, distant galaxy cluster SDSS J0150–1005

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Research in Astronomy and Astrophysics 2013年第10期13卷 1155-1162页

作者： Zhen-Zhen qin Hai-guang Xu Jing-Ying Wang Jun-Hua Gu Department of Physics Shanghai Jiao Tong University National Astronomical Observatories Chinese Academy of Sciences

We present a study of a fossil cluster,SDSS J0150–1005（z 0.364）,with high spatial resolution based on the imaging spectroscopic analysis of Chandra *** Chandra X-ray image shows a relaxed and symmetric morphology,which indicates that SDSS J0150–1005 is a well-developed galaxy cluster with no sign of a recent *** to the isothermal model,its global gas temperature is 5.73±0.80 keV,and the virial mass is 6.23±1.34×1014M⊙.Compared with the polytropic temperature model,the mass calculated based on the isothermal model is overestimated by 49%±*** central gas entropy,S0.1 r200=143.9±18.3 keV cm2,is significantly lower than the average value of normal galaxy clusters with similar *** results indicate that SDSS J0150–1005 formed during an early epoch.

关键词： galaxies:clusters:general galaxies:evolution galaxies:halos—intergalactic medium X-rays:galaxies:clusters

Effects of UV-B radiation intensity and timing on epidemiological components of wheat stripe rust

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Journal of Integrative Agriculture 2018年第12期17卷 2704-2713页

作者： WANG Hui qin Feng CHENG Pei MA Zhan-hong WANG Hai-guang Department of Plant Pathology China Agricultural UniversityBeijing 100193P.R.China Rizhao Agricultural Bureau of Shandong Province Rizhao 276800P.R.China

Stripe rust caused by Puccinia striiformis f. sp. tritici is an important wheat disease worldwide that is greatly influenced by environmental conditions. Ultraviolet B(UV-B) radiation is one important environmental factor affecting the occurrence and epidemiology of wheat stripe rust. Investigating UV-B radiation effects on the epidemiology of stripe rust may be conducive to monitoring and predicting this disease. In this study, wheat seedlings were exposed to UV-B radiation during different periods under laboratory conditions and radiation effects on epidemiological components of wheat stripe rust were investigated. Results showed that incubation period was shortened, and the infection efficiency, sporulation quantity and disease index increased when UV-B radiation was performed only pre-inoculation. When the UV-B radiation was performed only postinoculation or both pre-and post-inoculation, the incubation period was prolonged, and the infection efficiency, sporulation quantity and disease index were reduced. When healthy wheat seedlings were inoculated using urediospores collected from wheat leaves irradiated by UV-B only post-inoculation or both pre-and post-inoculation, infection efficiency, sporulation quantity and disease index were also reduced. However, in the latter, the disease incubation period did not differ under varying UV-B radiation intensities compared to that when wheat leaves were not treated with UV-B radiation. Overall, the effects of direct exposure of wheat plants to UV-B radiation with different intensities in different periods on epidemiological components of wheat stripe rust were systematically explored, and the results suggest that the effects of UV-B radiation increased gradually with the increase of UV-B radiation intensity. This information provides a basis for monitoring and predicting this disease as well as for conducting further studies on pathogen virulence variation.

关键词： wheat stripe rust UV-B radiation epidemiological component Puccinia striiformis f.sp.tritici