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Periodic atomization characteristics of an impinging jet injector element modulated by Klystron effect

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Chinese Journal of Aeronautics 2018年第10期31卷 1973-1984页

作者： Anlong yang Bin LI shangrong yang Yunfei XU Longfei LI Science and Technology on Liquid Rocket Engine Laboratory Xi'an Aerospace Propulsion Institute

An experimental study on the Klystron effect of periodic injection modulated by pressure drop fluctuations on subsequent atomization is conducted. Time-resolved atomization backlit images and atomization Mie scatter images are captured by using the high speed camera. It is found that periodicity of forced atomization relies on pressure drop fluctuation amplitude and phase differences between atomization and pressure drop fluctuations relate to fluctuation frequencies. This feature of periodic atomization induced by Klystron effect corresponds to periodicities and high amplitudes of pressure fluctuations in unstable combustion chambers and chaos and low amplitudes of pressure fluctuations in stable combustions chambers. Drastically periodic varying of gross surface area of droplets with time was shown in Mie scatter images. The importance of periodic impinging jet atomization modulated by pressure drop fluctuations for acoustic liquid propellant combustion instabilities is illustrated.

关键词： Atomization Combustion stability Impinging jet injector Klystron effect Liquid rocket engine Mie scatter

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缩进长度对同轴离心式喷嘴燃烧稳定性的影响

推进技术 2024年第7期45卷 135-143页

作者：杨尚荣吴林龙李娜王勇杨宝娥西安航天动力研究所液体火箭发动机技术重点实验室陕西西安710100

针对缩进长度对气体中心液体离心式同轴(GCLSC)喷嘴(简称同轴离心式喷嘴)燃烧稳定性的影响,开展富氧气/煤油同轴离心式单喷嘴燃烧稳定性实验研究。通过改变燃料和氧化剂喷射速度,获得了三种缩进长度喷嘴(8,10,12 mm)的稳定性图或稳定性... 详细信息

针对缩进长度对气体中心液体离心式同轴(GCLSC)喷嘴(简称同轴离心式喷嘴)燃烧稳定性的影响,开展富氧气/煤油同轴离心式单喷嘴燃烧稳定性实验研究。通过改变燃料和氧化剂喷射速度,获得了三种缩进长度喷嘴(8,10,12 mm)的稳定性图或稳定性边界。利用高速相机拍摄了火焰的CH*自发光图像,通过动力学模态分解(DMD)方法分析了燃烧流场的空间结构。研究发现:当氧化剂速度足够高时,三种缩进长度喷嘴均出现了不稳定燃烧。燃料速度≤11 m/s时,滞后区域较窄或不存在,燃料速度>11 m/s,滞后区域变宽。10 mm缩进长度喷嘴的稳定性边界最大,滞后边界在燃料速度≤11 m/s时最大。相比稳定燃烧状态火焰长度,发生不稳定后,火焰长度显著缩短,且在横向扩展。三种缩进长度喷嘴在稳定和不稳定燃烧状态下,CH*自发光均紧贴喷嘴出口,说明燃烧在缩进室内部便已开始。一阶切向不稳定对应的DMD模态应为流向涡和角向涡耦合产生的螺旋形不稳定涡结构。

关键词：同轴离心式喷嘴缩进长度燃烧稳定性动力学模态分解螺旋形涡

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同轴离心式喷嘴火焰结构的转变和迟滞

燃烧科学与技术 2024年第3期30卷 255-264页

作者：杨尚荣李娜吴林龙王勇杨宝娥连俊凯西安航天动力研究所液体火箭发动机技术重点实验室西安710100

针对气体中心液体离心式同轴(GCLSC)喷嘴(简称为同轴离心式喷嘴)的燃烧动力学特性,开展富氧气/煤油蒸气同轴离心式单喷嘴实验研究.通过改变氧化剂喷射速度,分别获得了稳定和自发激励条件下的火焰结构、相互转变和迟滞过程.利用高速相机... 详细信息

针对气体中心液体离心式同轴(GCLSC)喷嘴(简称为同轴离心式喷嘴)的燃烧动力学特性,开展富氧气/煤油蒸气同轴离心式单喷嘴实验研究.通过改变氧化剂喷射速度,分别获得了稳定和自发激励条件下的火焰结构、相互转变和迟滞过程.利用高速相机拍摄了火焰的CH^(*)自发光图像,通过离散傅里叶变换(DFT)和动力学模态分解(DMD)方法分析了燃烧流场的空间结构.研究发现:稳定燃烧时,火焰长度较长,CH^(*)自发光紧贴喷嘴出口,火焰结构受反应混合层流动不稳定控制.迟滞区域内,火焰出现抬升,CH^(*)自发光强度沿流向存在两个峰值,主导的不稳定频率较高.不稳定燃烧时,火焰长度显著缩短,且在横向扩展,沿喷嘴周向有部分火焰紧贴喷嘴出口.3种燃烧状态下,DFT和DMD方法得到的空间模态均很相近.发现了螺旋形结构的低频火焰模态,某些工况下会发生对流形式的燃烧不稳定.一阶切向不稳定的火焰模态表现为速度耦合产生的螺旋形不稳定涡结构,二阶切向不稳定的火焰模态表现为压力耦合产生的对称涡结构.

关键词：同轴离心式喷嘴燃烧稳定性火焰结构迟滞模态分解

Risk of gestational diabetes recurrence and the development of type 2 diabetes among women with a history of gestational diabetes and risk factors: a study among 18 clinical centers in China

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Chinese Medical Journal 2022年第6期135卷 665-671页

作者： Yumei Wei Juan Juan Rina Su Geng Song Xu Chen Ruiqin Shan Ying Li Shihong Cui shangrong Fan Ling Feng Zishan You Haixia Meng Yan Cai Cuilin Zhang Huixia yang Department of Obstetrics and Gynecology Peking University First HospitalBeijing 100034China Department of Obstetrics Tianjin Central Obstetrics and Gynecology HospitalTianjin 300199China Department of Obstetrics Jinan Maternal and Child Health HospitalJinanShandong 250000China Department of Obstetrics Dalian Maternity HospitalDalianLiaoning 116033China Department of Obstetrics and Gynecology The Third Affiliated Hospital of Zhengzhou UniversityZhengzhouHenan 450052China Department of Obstetrics Shenzhen Peking University HospitalShenzhenGuangdong 518036China Department of Obstetrics and Gynecology Tongji Hospital Affiliated to Huazhong University of Science and TechnologyWuhanHubei 430030China Department of Obstetrics and Gynecology Suzhou Jiulong Hospital Affiliated to Shanghai Jiaotong UniversitySuzhouJiangsu 320571China Department of Obstetrics Affiliated Hospital of Inner Mongolia Medical UniversityHuhhotInner Mongolia 010050China Department of Obstetrics and Gynecology The Fourth Affiliated Hospital of Harbin Medical UniversityHarbinHeilongjiang 150001China Epidemiology Branch Division of Intramural Population Health ResearchEunice Kennedy Shriver National Institute of Child Health and Human DevelopmentNational Institutes of HealthBethesdaMD 20817USA

Background:Gestational diabetes mellitus(GDM)brings health issues for both mothers and offspring,and GDM prevention is as important as GDM management.It was shown that a history of GDM was significantly associated with a higher maternal risk for GDM recurrence.The incidence of GDM recurrence was unclear because of the incidence of second-child was low before 2016 in China.We aim to investigate the prevalence of GDM recurrence and its associated high-risk factors which may be useful for the prediction of GDM recurrence in China.Methods:A retrospective study was conducted which enrolled participants who underwent regular prenatal examination and delivered twice in the same hospital of 18 research centers.All participants were enrolled from January 2018 to October 2018,where they delivered the second baby during this period.A total of 6204 women were enrolled in this study,and 1002 women with a history of GDM were analyzed further.All participants enrolled in the study had an oral glucose tolerance test(OGTT)result at 24 to 28 weeks and were diagnosed as GDM in the first pregnancy according to the OGTT value(when any one of the following values is met or exceeded to the 75-g OGTT:0 h[fasting],≥5.10 mmol/L;1 h,≥10.00 mmol/L;and 2 h,≥8.50 mmol/L).The prevalence of GDM recurrence and development of type 2 diabetes mellitus were calculated,and its related risk factors were analyzed.Results:In 6204 participants,there are 1002 women(1002/6204,16.15%)with a history of GDM and 5202 women(5202/6204,83.85%)without a history of GDM.There are significant differences in age(32.43±4.03 years vs.33.00±3.34 years vs.32.19±3.37 years,P<0.001),pregnancy interval(4.06±1.44 years vs.3.52±1.43 years vs.3.38±1.35 years,P=0.004),prepregnancy body mass index(BMI)(27.40±4.62 kg/m^(2)vs.23.50±3.52 kg/m^(2)vs.22.55±3.47 kg/m^(2),P<0.001),history of delivered macrosomia(22.7%vs.11.0%vs.6.2%,P<0.001)among the development of diabetes mellitus(DM),recurrence of GDM,and normal women.Moreover,it seems so important in the degree of abnormal glucose

关键词： Gestational diabetes mellitus Recurrence Risk factors Multipara Primipara

Rationale and design of a randomised double-blind 2×2 factorial trial comparing the effect of a 3-month intensive statin and antiplatelet therapy for patients with acute mild ischaemic stroke or high-risk TIA with intracranial or extracranial atherosclerosis(INSPIRES)

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Stroke & Vascular Neurology 2023年第3期8卷 249-258,I0096-I0110页

作者： Ying Gao Yuesong Pan shangrong Han Weiqi Chen Jing Jing Chunjuan Wang Yingying yang Tingting Wang Xia Meng Xingquan Zhao Liping Liu Hao Li S Claiborne Johnston Pierre Amarenco Philip M Bath Yongjun Wang Yilong Wang Department of Neurology Beijing Tiantan HospitalCapital Medical UniversityBeijingChina China National Clinical Research Center for Neurological Diseases Beijing Tiantan HospitalCapital Medical UniversityBeijingChina Dean's Office Dell Medical SchoolUniversity of Texas at AustinAustinTexasUSA Department of Neurology and Stroke Center Assistance Publique-Hôpitaux de Paris(APHP)Bichat HospitalINSERM LVTS-U1148University of ParisParisFrance Population Health Research Institute McMaster UniversityHamiltonOntarioCanada Stroke Trials Unit Mental Health&Clinical NeuroscienceUniversity of NottinghamNottinghamUK Advanced Innovation Center for Human Brain Protection Capital Medical UniversityBeijingChina National Center for Neurological Diseases BeijingChina Research Unit of Artificial Intelligence in Cerebrovascular Disease Chinese Academy of Medical SciencesBeijingChina Chinese Institute for Brain Research BeijingChina

Background It remains unclear if intensive antiplatelet and statin treatments begun within 24-72 hours of cerebral ischaemic events from intracranial or extracranial atherosclerosis is effective or safe.Methods The Intensive Statin and Antiplatelet Therapy for High-risk Intracranial or Extracranial Atherosclerosis(INSPIRES)trial is a randomised,double-blind,placebo-controlled,multicentre and 2×2 factorial trial.6100 individuals between the ages of 35 and 80 who have experienced a mild ischaemic stroke or high-risk transient ischaemic attack(TIA)within the previous 72 hours that is attributed to≥50%atherosclerotic stenosis of a major intracranial or extracranial artery or multiple infarctions of atherosclerotic origin will be enrolled in the trial.Eligible subjects will be randomised 1:1:1:1 to one of four groups:(1)intensive antiplatelet therapy(combined clopidogrel and aspirin for days 1-21,then aspirin placebo and clopidogrel for days 22-90)plus immediate intensive statin therapy(atorvastatin at a dose of 80 mg daily for the first 21 days,then 40 mg daily for days 22-90);(2)intensive antiplatelet therapy plus delayed intensive statin therapy(atorvastatin placebo for days 1-3,followed by 40 mg per day of atorvastatin for days 4-90);(3)standard antiplatelet therapy(combination of clopidogrel placebo with aspirin for 90 days)plus immediate intensive statin therapy and(4)standard antiplatelet therapy plus delayed intensive statin therapy.The primary efficacy endpoint is any new stroke(ischaemic or haemorrhagic)within 90 days after randomisation.The primary safety endpoint is moderate to severe bleeding at 90 days.Conclusion The INSPIRES trial will assess the efficacy and safety of intensive antiplatelet therapy and immediate intensive statin therapy begun within 72 hours of onset in decreasing the recurrent stroke at 90 days in patients with acute mild ischaemic stroke or high-risk TIA of intracranial or extracranial atherosclerosis origin.

关键词： intracranial atherosclerosis random

Gene expression dynamics during the gonocyte to spermatogonia transition and spermatogenesis in the domestic yak

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Journal of Animal Science and Biotechnology 2019年第4期10卷 907-918页

作者： Guowen Wang Yongchang Li Qilin yang shangrong Xu Shike Ma Rongge Yan Ruina Zhang Gongxue Jia Deqiang Ai Qi’en yang Key Laboratory of Adaptation and Evolution of Plateau Biota Northwest Institute of Plateau BiologyChinese Academy of SciencesXining 810000QinghaiChina University of Chinese Academy of Sciences Beijing 100049China Department of Veterinary Sciences Qinghai Vocational and Technical Institute of Animal Husbandry and VeterinaryQinghai UniversityXining 810016China Qinghai Academy of Animal Science and Veterinary Medicine Qinghai UniversityXining 810016China Animal Husbandry Technology Extension Station of Qinghai Province Xining 810001QinghaiChina Qinghai Key Laboratory of Animal Ecological Genomics Northwest Institute of Plateau BiologyChinese Academy of SciencesXining 810001QinghaiChina CAS Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing 100101China

Background:Spermatogenesis is a cellular differentiation process that includes three major events:mitosis of spermatogonia,meiosis of spermatocytes and spermiogenesis.Steady-state spermatogenesis relies on functions of spermatogonial stem cells(SSCs).Establishing and maintaining a foundational SSC pool is essential for continued spermatogenesis in mammals.Currently,our knowledge about SSC and spermatogenesis is severely limited in domestic animals.Results:In the present study,we examined transcriptomes of testes from domestic yaks at four different stages(3,5,8 and 24 months of age)and attempted to identify genes that are associated with key developmental events of spermatogenesis.Histological analyses showed that the most advanced germ cells within seminiferous tubules of testes from 3,5,8 and 24 months old yaks were gonocytes,spermatogonia,spermatocytes and elongated spermatids,respectively.RNA-sequencing(RNA-seq)analyses revealed that 11904,4381 and 2459 genes were differentially expressed during the gonocyte to spermatogonia transition,the mitosis to meiosis transition and the meiosis to post-meiosis transition.Further analyses identified a list of candidate genes than may regulate these important cellular processes.CXCR4,a previously identified SSC niche factor in mouse,was one of the up-regulated genes in the 5 months old yak testis.Results of immunohistochemical staining confirmed that CXCR4 was exclusively expressed in gonocytes and a subpopulation of spermatogonia in the yak testis.Conclusions:Together,these findings demonstrated histological changes of postnatal testis development in the domestic yak.During development of spermatogonial lineage,meiotic and haploid germ cells are supported by dynamic transcriptional regulation of gene expression.Our transcriptomic analyses provided a list of candidate genes that potentially play crucial roles in directing the establishment of SSC and spermatogenesis in yak.

关键词： Gonocyte Meiosis Spermatogenesis Spermatogonia Transcriptome

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同轴离心式喷嘴燃烧稳定性增长率识别

振动与冲击 2023年第18期42卷 332-337页

作者：杨尚荣吴林龙于涵杨宝娥西安航天动力研究所液体火箭发动机技术重点实验室西安710100

为确定同轴离心式喷嘴燃烧不稳定的线性增长率,基于随机动力学Fokker-Planck体系系统识别方法,利用脉动压力时间序列识别喷嘴4种工况下的增长率,并分析了结果的不确定性和参数敏感性。结果表明:变换脉动压力的单位进行识别,增长率不变,... 详细信息

为确定同轴离心式喷嘴燃烧不稳定的线性增长率,基于随机动力学Fokker-Planck体系系统识别方法,利用脉动压力时间序列识别喷嘴4种工况下的增长率,并分析了结果的不确定性和参数敏感性。结果表明:变换脉动压力的单位进行识别,增长率不变,饱和系数和噪声强度存在确定的变换关系,且三者的识别精度不变;负增长率的声模态在噪声作用下也可能发生较大幅值的压力振荡;增加脉动压力采样时间可以提高增长率的识别精度,不同工况下存在各自较优的采样率。从脉动压力时间序列线性增长阶段识别增长率同样需要考虑噪声导致的不确定性。

关键词：同轴离心式喷嘴燃烧不稳定燃烧噪声增长率输出识别

Prevalence and characteristics of macrosomia in the first and subsequent pregnancy: a multi-center retrospective study

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Chinese Medical Journal 2022年第12期135卷 1492-1494页

作者： Juan Juan Huixia yang Yumei Wei Geng Song Rina Su Xu Chen Ruiqin Shan Jianying Yan Mei Xiao Ying Li Shihong Cui Xianlan Zhao shangrong Fan Ling Feng Meihua Zhang Yuyan Ma Zishan You Haixia Mengn Haiwei Liu Jingxia Sun Yan Cai Kejia Hu Department of Obstetrics and Gynecology Peking University First HospitalBeijing 100034China Department of Obstetrics Tianjin Central Obstetrics and Gynecology HospitalTianjin 300199China Department of Obstetrics Jinan Maternal and Child Health HospitalJinanShandong 250000China Department of Obstetrics Fujian Province Maternal and Child Health HospitalFuzhouFujian 350001China Department of Obstetrics Maternal and Child Hospital of Hubei ProvinceWuhanHubei 430070China Department of Obstetrics Dalian Maternity HospitalDalianLiaoning 116033China Department of Obstetrics and Gynecology The Third Affiliated Hospital of Zhengzhou UniversityZhengzhouHenan 450052China Department of Obstetrics and Gynecology The First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenan 450003China Department of Obstetrics Shenzhen Peking University HospitalShenzhenGuangdong 518036China Department of Obstetrics and Gynecology Tongji Hospital Affiliated to Huazhong University of Science and TechnologyWuhanHubei 430030China Department of Obstetrics Taiyuan Maternal and Child Health HospitalTaiyuanShanxi 030012China Department of Obstetrics and Gynecology Qilu Hospital of Shandong UniversityJinanShandong 250012China Department of Obstetrics and Gynecology Suzhou Jiulong Hospital Affiliated to Shanghai Jiaotong UniversitySuzhouJiangsu 320571China Department of Obstetrics Affiliated Hospital of Inner Mongolia Medical UniversityHuhhotInner Mongolia 010050China Department of Endocrinology Hainan General HospitalHaikouHainan 570311China Department of Obstetrics and Gynecology The First Affiliated Hospital of Harbin Medical UniversityHarbinHeilongjiang 150007China Department of Obstetrics and Gynecology The Fourth Affiliated Hospital of Harbin Medical UniversityHarbinHeilongjiang 150026China Department of Obstetrics The Hospital of Shunyi District BeijingBeijing 101312China

To the Editor:Macrosomia is of growing prevalence and concern worldwide.In China,there has been a marked increase in the prevalence of macrosomia over the past few decades as a result of economic development and impro... 详细信息

关键词： prevalence pregnancy subsequent

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同轴离心式喷嘴燃烧实验中的间歇性压力振荡

工程热物理学报 2022年第7期43卷 1986-1991页

作者：杨尚荣王勇张锋杨宝娥王牧昕西安航天动力研究所液体火箭发动机技术重点实验室西安710100 中国航天科工集团公司六院210所西安710065

为获得同轴离心式喷嘴燃烧动力学特性,开展了喷注单元燃烧实验研究。实验中增加混合比,燃烧室从燃烧噪声状态转变为规则的间歇性压力振荡状态。减小混合比,在稳定性边界附近出现了随机间歇性压力振荡。通过引入慢变量振荡,建立了燃烧系... 详细信息

为获得同轴离心式喷嘴燃烧动力学特性,开展了喷注单元燃烧实验研究。实验中增加混合比,燃烧室从燃烧噪声状态转变为规则的间歇性压力振荡状态。减小混合比,在稳定性边界附近出现了随机间歇性压力振荡。通过引入慢变量振荡,建立了燃烧系统的随机动力学模型,分析了系统线性衰减率、噪声强度和慢变量振荡耦合强度等参数对系统动力学的影响。结果表明,理论模型较好的描述了实验中出现的间歇性压力振荡现象,引入慢变量振荡使系统出现了较规则的间歇性压力振荡,规则程度与噪声强度有关。此外,高强度的噪声可以引发随机间歇性压力振荡。

关键词：同轴离心式喷嘴燃烧不稳定间歇性振荡快慢系统