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Analysis of the Pump-turbine S Characteristics Using the Detached Eddy Simulation Method

Chinese Journal of Mechanical Engineering 2015年第1期28卷 115-122页

作者： SUN Hui XIAO Ruofu WANG Fujun XIAO Yexiang liu weichao College of Water Resources and Civil Engineering China Agricultural University State Key Laboratory of Hydroscience and Engineering & Department of Thermal Engineering Tsinghua University Dongfang Electric Machinery Co. Ltd

Current research on pump-turbine units is focused on the unstable operation at off-design conditions, with the characteristic curves in generating mode being S-shaped. Unlike in the traditional water turbines, pump-turbine operation along the S-shaped curve can lead to difficulties during load rejection with unusual increases in the water pressure, which leads to machine vibrations. This paper describes both model tests and numerical simulations. A reduced scale model of a low specific speed pump-turbine was used for the performance tests, with comparisons to computational fluid dynamics（CFD） results. Predictions using the detached eddy simulation（DES） turbulence model, which is a combined Reynolds averaged Naviers-Stokes（RANS） and large eddy simulation（LES） model, are compared with the two-equation turbulence mode results. The external characteristics as well as the internal flow are for various guide vane openings to understand the unsteady flow along the so called S characteristics of a pump-turbine. Comparison of the experimental data with the CFD results for various conditions and times shows that DES model gives better agreement with experimental data than the two-equation turbulence model. For low flow conditions, the centrifugal forces and the large incident angle create large vortices between the guide vanes and the runner inlet in the runner passage, which is the main factor leading to the S-shaped characteristics. The turbulence model used here gives more accurate simulations of the internal flow characteristics of the pump-turbine and a more detailed force analysis which shows the mechanisms controlling of the S characteristics.

关键词： pump-turbine S-shaped characteristics detached eddy simulation(DES) numerical analysis

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胸腔镜治疗原发性纵隔肿瘤及对T淋巴细胞因子的影响

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实用肿瘤杂志 2019年第1期34卷 47-51页

作者：刘伟超河南大学淮河医院胸心血管外科河南开封475000

目的研究电视胸腔镜手术(videoassisted thoracoscopic surgery,VATS)治疗原发性纵隔肿瘤(primary mediastinal tumor,PMT)及其对T淋巴细胞因子的影响。方法选择90例PMT患者按照手术方式分为VATS组(n=45)与开胸组(n=45)。VATS组行VATS治疗,开胸组行开胸切除术。观察指标为:术中失血量、手术时间、镇痛药物使用时间、引流时间及住院时间等手术指标,术前与术后7 d血清白介素-6(interleukin-6,IL-6)、IL-1β、肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)和C反应蛋白(C-reactive protein,CRP)等炎性因子,术前与术后7 d血清CD3^+、CD4^+、CD8^+和CD4^+/CD8^+等T淋巴细胞因子,术后并发症等。结果VATS组术中出血量、手术时间、镇痛药物使用时间、引流时间及住院时间等均小于开胸组,差异均具有统计学意义(均P<0.05)。术后3 d,VATS组IL-6、IL-1β、TNF-α和CRP水平均低于开胸组,组间差异均具有统计学意义(均P<0.05)。术后7 d,VATS组CD3^+、CD4^+和CD4^+/CD8^+高于开胸组,CD8^+低于开胸组,差异均具有统计学意义(均P<0.05)。VATS组术后并发症发病率(4.4%)低于开胸组(20.0%),差异具有统计学意义(P<0.05)。结论VATS治疗PMT可有效切除病灶,有利于免疫机制恢复,炎性反应小,术后并发症发生率低。

关键词：纵隔肿瘤/外科学胸腔镜检查 T淋巴细胞/免疫学细胞因子类/代谢

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Adsorption of acid fuchsin onto LTA-type zeolite derived from fly ash

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Science China(Technological Sciences) 2014年第6期57卷 1127-1134页

作者： XU HuanYan WU LiCheng SHI TianNuo liu weichao QI ShuYan School of Materials Science and Engineering Harbin University of Science and Technology

A facile strategy without organic template was developed for the conversion of fly ash to LTA-type zeolite(LTA-Z),which could be used as a good adsorbent for the removal of acid fuchsin(AF).XRD results indicated that the pure crystalline product was obtained with the structure of LTA-type *** investigations showed that the well-defined LTA-Z crystals exhibited uniform size with the same cubic *** maximum AF adsorption amount was observed at pH=5,slightly lower than pHPZC of *** temperature favored AF adsorption onto LTA-Z and it was an endothermic ***,AF adsorption amount increased with initial AF concentration increasing and LTA-Z dosage *** sorption governed this process at the initial 120 min period,followed by the internal diffusion of AF molecules between porous *** Langmuir model was determined as the adsorption isothermal,suggesting that the monolayer coverage of AF on LTA-Z surface was involved.

关键词： LTA-type zeolite fly ash acid fuchsin kinetics isotherms

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Probiotic properties of Lactobacillus paraplantarum LS-5 and its effect on antioxidant activity of fermented sauerkraut

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Food Bioscience 2023年第2期52卷 1303-1313页

作者： Hongchi Zhou Sixuan Wang weichao liu Lixuan Chang Xuemei Zhu Guangqing Mu Fang Qian School of Food Science and Technology Dalian Polytechnic UniversityLiaoning116000China

This study aimed to investigate the safety and probiotic properties of Lactobacillus paraplantarum LS-5 isolated from traditional northeastern sauerkraut,and to assess the antioxidant capacity of different solvent extracts(ethanol,water,and hot water)of *** LS-5-inoculated *** LS-5 was shown to have various probiotic characteristics,such as good survival ability under artificial gastrointestinal conditions,antagonistic activity of various pathogens,non-biogenic amines,antibiotic susceptibility,and *** 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonate(ABTS)radical scavenging activity of the *** LS-5-inoculated sauerkraut alcohol extract(71.13%)was significantly higher than water extract(59.59%)(p<0.05).The ferric reducing antioxidant power(FRAP)of sauerkraut alcohol extract(614.93 Troloxμmol L^(-1))exhibited a slightly stronger ability compared to water extract(388.53 Troloxμmol L^(-1))and the heated sauerkraut water extract(383.20 Troloxμmol L^(-1))at extract concentrations of 5.0 mg mL^(-1).Its 1,1-diphenyl1-2-picrylhydrazyl(DPPH)radical scavenging activity was also *** was found by principal component analysis(PCA)and Pearson that the DPPH radical-scavenging activities of sauerkraut extracts were significantly correlated with the content of polyphenols and flavonoids(p<0.05).Unlike kimchi,Northeastern sauerkraut is consumed mainly by heating,so this study could contribute to understanding the antioxidant capacity of different solvent extracts of sauerkraut,and before and after heating water extracts.

关键词： Lactobacillus paraplantarum Probiotic properties Fermentation vegetable Radical-scavenging

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Responses of plant community to the linkages in plant-soil C:N:P stoichiometry during secondary succession of abandoned farmlands,China

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Journal of Arid Land 2020年第2期12卷 215-226页

作者： liu weichao FU Shuyue YAN Shengji REN Chengjie WU Shaojun DENG Jian LI Boyong HAN Xinhui YANG Gaihe College of Agronomy Northwest A&F UniversityYangling 712100China Research Center of Recycle Agricultural Engineering and Technology of Shaanxi Province Yangling 712100China School of Life Science Yan'an UniversityYan'an 716000China

Succession is one of the central themes of ecology;however,the relationship between aboveground plant communities and underground soils during secondary succession remains *** this study,we investigated the composition of plant community,plant-soil C:N:P stoichiometry and their relationships during secondary succession after the abandonment of farmlands for 0,10,20,30,40 and 50 a in China,*** showed that the composition of plant communities was most diverse in the farmlands after secondary succession for 20 and 50 *** organic carbon and total nitrogen contents slightly decreased after secondary succession for 30 a,but both were significantly higher than those of control farmland(31.21%-139.10%and 24.24%-121.21%,respectively).Moreover,C:N ratios of soil and microbe greatly contributed to the changes in plant community composition during secondary succession of abandoned farmlands,explaining 35.70%of the total ***,soil C:N ratio was significantly and positively related with the Shannon-Wiener *** study provides the evidence of synchronous evolution between plant community and soil during secondary succession and C:N ratio is an important linkage between them.

关键词： C:N ratio soil nutrient plant community restoration loess hilly region

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Three new Cu(Ⅱ)-Ln(Ⅲ) heterometallic coordination polymers constructed from quinolinic acid and nicotinic acid: Synthesis, structures, and magnetic properties

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Science China Chemistry 2012年第6期55卷 1064-1072页

作者： liu SuiJun SONG weichao XUE Li HAN SongDe ZENG YongFei WANG LiFu BU XianHe Department of Chemistry Tianjin Key Laboratory of Metal & Molecule-based Material Chemistry Nankai University Tianjin 300071 China

Three new Cu（Ⅱ）-Ln（Ⅲ） heterometallic coordination polymers based on two N-heterocyclic carboxylic ligands, {[LnCu（LI）2（L2）（H2O）2]· mH20},, （Ln = La（1）, Nd（2）, Gd（3）, m = 2 （for 1）, 1 （for 2, 3）, H2L1 = quinolinic acid, HE2 = nico- tinic acid）, have been synthesized and characterized. 1 has a two-dimensional （2D） layer structure with a Schlifli symbol of （44.62）, while complexes 2 and 3 are isostructural and have three-dimensional （3D） structures with a Schlafli symbol of （3.4.5）2（32.***.52.6]4.***.83.9）（32.63.7） of 3-nodal net. Magnetic investigations suggest that antiferromagnetic coupling exists be- tween NdIn and Cun in 2, while weak ferromagnetic coupling between GdⅢ and CuⅡ in 3. The difference of magnetic properties between 2 and 3 has been discussed.

关键词： Cu(Ⅱ)-Ln(Ⅲ) coordination polymers metal oxides magnetic properties

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Thinking about Development of Blockchain

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China Economic Transition 2020年第2期3卷 45-59页

作者： HAN Junyan REN Siming liu weichao of China Union Pay Merchant Services Co. Ltd.

Understanding the blockchain The global enthusiasm for blockchain was sparked by Bitcoin,which has been the most successful application of this te-chnology to *** Nakamoto’s article,Bitcoin:A Peer-to-Peer Electronic Cash System,although specific to Bitcoin,remains the leading literature for the study of blockchain *** article therefore uses Nakamoto’s paper as the theoretical basis,and Bitcoin as a case study,for a new analysis in the nature of blockchain.

关键词： technology. has although

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A high-quality Bougainvillea genome provides new insights into evolutionary history and pigment biosynthetic pathways in the Caryophyllales

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Horticulture Research 2023年第8期10卷 85-96页

作者： Lan Lan Huiqi Zhao Suxia Xu Shenglong Kan Xiaoni Zhang weichao liu Xuezhu Liao Luke RTembrock Yonglin Ren Wayne Reeve Jun Yang Zhiqiang Wu Shenzhen Branch Guangdong Laboratory of Lingnan Modern AgricultureGenome Analysis Laboratory of the Ministry of Agriculture and Rural AffairsAgricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhen518120China School of Medical Molecularand Forensic SciencesMurdoch University6150Western Australia90 South StreetMurdochAustralia Kunpeng Institute of Modern Agriculture at Foshan Shenzhen BranchGuangdong Laboratory of Lingnan Modern AgricultureAgricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhen 518124China Sanya Institute Hainan Academy of Agricultural SciencesSanya572025China Institute of Tropical Horticulture Research Hainan Academy of Agricultural SciencesHaikou571100China Fujian Key Laboratory of Subtropical Plant Physiology&Biochemistry Fujian Institute of Subtropical BotanyXiamen361006China Key Laboratory of Horticultural Plant Biology College of Horticulture and Forestry SciencesHuazhong Agricultural UniversityWuhan430070China Department of Agricultural Biology Colorado State UniversityFort CollinsCO80523USA

Bougainvillea is a perennial ornamental shrub that is highly regarded in ornamental horticulture around the ***,the absence of genome data limits our understanding of the pathways involved in bract coloration and ***,we report a chromosome-level assembly of the giga-genome of Bougainvillea×buttiana‘Mrs Butt’,a cultivar thought to be the origin of many other Bougainvillea *** assembled genome is∼5 Gb with a scaffold N50 of 151756278 bp and contains 86572 genes which have undergone recent whole-genome *** confirmed that multiple rounds of whole-genome multiplication have occurred in the evolutionary history of the Caryophyllales,reconstructed the relationship in the Caryophyllales at whole genome level,and found discordance between species and gene trees as the result of complex introgression *** investigated betalain and anthocyanin biosynthetic pathways and found instances of independent evolutionary innovations in the nine different Caryophyllales *** explore the potential formation mechanism of diverse bract colors in Bougainvillea,we analyzed the genes involved in betalain and anthocyanin biosynthesis and found extremely low expression of ANS and DFR genes in all cultivars,which may limit anthocyanin *** findings indicate that the expression pattern of the betalain biosynthetic pathway did not directly correlate with bract color,and a higher expression level in the betalain biosynthetic pathway is required for colored *** improved understanding of the correlation between gene expression and bract color allows plant breeding outcomes to be predicted with greater certainty.

关键词： evolutionary insight breeding

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飞行模拟器洗出算法多重滤波信号补偿优化研究

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系统仿真学报 2023年第1期35卷 137-145页

作者：刘伟超王辉中国民航大学航空工程学院天津300300

针对经典洗出算法在应用于飞行模拟器时存在的信号丢失以及适应性不强的缺陷,提出一种多重滤波信号补偿的洗出算法优化方案。分析经典洗出算法中信号丢失的环节,截取丢失信号并采取深度滤波策略进行深度滤波,依据人体感知误差与运动平... 详细信息

针对经典洗出算法在应用于飞行模拟器时存在的信号丢失以及适应性不强的缺陷,提出一种多重滤波信号补偿的洗出算法优化方案。分析经典洗出算法中信号丢失的环节,截取丢失信号并采取深度滤波策略进行深度滤波,依据人体感知误差与运动平台的动作余量,将多重滤波后的信号以自适应的比例分别补偿到洗出算法3个通道中,实现最大程度上减小信号损失,从而减少人体感知误差。对经典洗出算法和改进洗出算法进行对比仿真和试验,结果表明改进洗出算法有效降低了人体感知误差,减少了信号丢失,改善了相位延迟,同时充分利用了运动平台的工作空间,增加了动感逼真度。

关键词：洗出算法飞行模拟器多重滤波人体感知动感逼真度

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Perioperative dexmedetomidine administration does not reduce the risk of acute kidney injury after non-cardiac surgery:a meta-analysis

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Chinese Medical Journal 2022年第23期135卷 2798-2804页

作者： Bin Hu Tian Tian Xintao Li weichao liu Yinggui Chen Tianyu Jiang Peishan Chen Fushan Xue Department of Anesthesiology Beijing Friendship HospitalCapital Medical UniversityBeijing 100050China

Background:Post-operative acute kidney injury(AKI)is one of the most common and serious complications after major surgery and is significantly associated with increased risks of morbidity and *** meta-analysis was conducted to evaluate the effects of perioperative dexmedetomidine(Dex)administration on the occurrence of AKI and the outcomes of recovery after non-cardiac ***:The PubMed,Embase,Web of Science,and Cochrane Library databases were systematically searched for studies comparing the effects of *** on kidney function after non-cardiac surgery,and a pooled fixed-effect meta-analysis of the included studies was *** primary outcome was the occurence of post-operative *** secondary outcomes included the occurence of intra-operative hypotension and bradycardia,intensive care unit(ICU)admission,duration of ICU stay,and hospital length of stay(LOS).Results:Six studies,including four randomized controlled trials(RCTs)and two observational studies,with a total of 2586 patients were *** with placebo,Dex administration could not reduce the odds of post-operative AKI(odds ratio[OR],0.44;95%confidence interval(CI),0.18-1.06;P=0.07;I^(2)=0.00%,P=0.72)in RCTs,but it showed a significant renoprotective effect(OR,0.67;95%CI,0.48-0.95;P=0.02;I^(2)=0.00%,P=0.36)in observational ***,Dex administration significantly increased the odds of intra-operative bradycardia and shortened the duration of ICU ***,there was no significant difference in the odds of intra-operative hypotension,ICU admission,and hospital ***:This meta-analysis suggests that perioperative Dex administration does not reduce the risk of AKI after non-cardiac ***,the quality of evidence for this result is low due to imprecision and inconsistent types of non-cardiac ***,large and high-quality RCTs are needed to verify the real effects of perioperative Dex administration on the occurrence of AKI and th

关键词： Dexmedetomidine Non-cardiac surgery Acute kidney injury Meta-analysis

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