检索结果-南通市图书馆

Effects of argon blowing at tundish upper nozzle on multiphase flow behavior in nozzle

Journal of Iron and Steel Research(International) 2022年第4期29卷 588-600页

作者： Xu-feng Qin Chang-gui Cheng Yang Li Wei-li Wu Yan Jin The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking Wuhan University of Science and TechnologyWuhan 430081HubeiChina

In continuous casting,the argon blowing at the tundish upper nozzle is usually used to prevent nozzle clogging,whose effect is closely related to the migration of argon bubbles and the flow behavior of the liquid steel in the nozzle.Here,to investigate the effects of argon blowing at the tundish upper nozzle on multiphase flow behavior in nozzle,a threedimensional model of the tundish–nozzle–mold was established for numerical simulation.The results indicate that the argon bubbles injected from the inner wall of the tundish upper nozzle first move downward along the nozzle wall under the action of the liquid steel.As the distance from the tundish upper nozzle increases,the argon bubbles gradually diffuse to the center of the nozzle.Compared with no argon blowing,the liquid steel velocity increases in the center of the nozzle and decreases near the wall with argon blowing.With increasing the argon flow rate,the concentration of bubbles in the nozzle increases,and the process of bubble group diffusion to the center region of the nozzle speeds up.This in turn increases the liquid steel velocity at the center of the nozzle but reduces near the wall.With increasing the casting speed,the concentration of bubbles in the nozzle decreases,the length of the bubble group near the nozzle wall is extended,and the liquid steel velocity at the center region and near-wall region of the nozzle increases.The mechanism of argon blowing at the tundish upper nozzle to prevent nozzle clogging is mainly realized by the isolation effect of the argon bubble group on the inner wall of the nozzle.

关键词： argon blowing Tundish upper nozzle Nozzle clogging Numerical simulation

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

argon mitigates post-stroke neuroinflammation by regulating M1/M2 polarization and inhibiting NF-κB/NLRP3 inflammasome signaling

引用

Journal of Molecular Cell Biology 2022年第12期14卷 31-45页

作者： Ke Xue Mian Qi Tongping She Zhenglin Jiang Yunfeng Zhang Xueting Wang Guohua Wang Lihua Xu Bin Peng Jiayi Liu Xinjian Song Yuan Yuan Xia Li Institute of Special Environmental Medicine Co-innovation Center of NeuroregenerationNantong UniversityNantong 226001China Stroke Center&Department of Neurology Affiliated Hospital of Nantong UniversityNantong 226001China Department of Rehabilitation Medicine Affiliated Nantong Rehabilitation Hospital of Nantong UniversityNantong 226002China

Neuroinflammation plays a vital role in cerebral ischemic stroke(IS).In the acute phase of IS,microglia are activated toward the pro-inflammatory(M1)and anti-inflammatory(M2)phenotypes.argon,an inert gas,can reduce neuroinflammation and alleviate ischemia/reperfusion(I/R)injury.However,whether argon regulates M1/M2 polarization to protect against I/R injury as well as the underlying mechanism has not been reported.In this study,we analyzed the activation and polarization of microglia after I/R injury with or without argon administration and explored the effects of argon on NLRP3 inflammasome-mediated inflammation in microglia in vitro and in vivo.The results showed that argon application inhibited the activation of M1 microglia/macrophage in the ischemic penumbra and the expression of proteins related to NLRP3 inflammasome and pyroptosis in microglia.argon administration also inhibited the expression and processing of IL-1β,a primary pro-inflammatory cytokine.Thus,argon alleviates I/R injury by inhibiting pro-inflammatory reactions via suppressing microglial polarization toward M1 phenotype and inhibiting the NF-κB/NLRP3 inflammasome signaling pathway.More importantly,we showed that argon worked better than the specific NLRP3 inflammasome inhibitor MCC950 in suppressing neuroinflammation and protecting against cerebral I/R injury,suggesting the therapeutic potential of argon in neuroinflammation-related neurodegeneration diseases as a potent gas inhibitor of the NLRP3 inflammasome signaling pathway.

关键词： argon neuroinflammation ischemia/reperfusion injury microglial polarization NLRP3 inflammasome pyroptosis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

argon reduces microglial activation and inflammatory cytokine expression in retinal ischemia/reperfusion injury

引用

Neural Regeneration Research 2021年第1期16卷 192-198页

作者： Ulrich Goebel Stefanie Scheid Sashko Spassov Nils Schallner Jakob Wollborn Hartmut Buerkle Felix Ulbrich Department of Anesthesiology and Critical Care Medical Center–University of FreiburgFaculty of MedicineUniversity of FreiburgFreiburgGermany

We previously found that argon exerts its neuroprotective effect in part by inhibition of the toll-like receptors(TLR)2 and 4.The downstream transcription factors signal transducer and activator of transcription 3(STAT3)and nuclear factor kappa B(NF-κB)are also affected by argon and may play a role in neuroprotection.It also has been demonstrated that argon treatment could mitigate brain damage,reduce excessive microglial activation,and subsequently attenuate brain inflammation.Despite intensive research,the further exact mechanism remains unclear.In this study,human neuroblastoma cells were damaged in vitro with rotenone over a period of 4 hours(to mimic cerebral ischemia and reperfusion damage),followed by a 2-hour post-conditioning with argon(75%).In a separate in vivo experiment,retinal ischemia/reperfusion injury was induced in rats by increasing intraocular pressure for 1 hour.Upon reperfusion,argon was administered by inhalation for 2 hours.argon reduced the binding of the transcription factors signal transducer and activator of transcription 3,nuclear factor kappa B,activator protein 1,and nuclear factor erythroid 2-related factor 2,which are involved in regulation of neuronal damage.Flow cytometry analysis showed that argon downregulated the Fas ligand.Some transcription factors were regulated by toll-like receptors;therefore,their effects could be eliminated,at least in part,by the TLR2 and TLR4 inhibitor oxidized phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine(OxPAPC).argon treatment reduced microglial activation after retinal ischemia/reperfusion injury.Subsequent quantitative polymerase chain reaction analysis revealed a reduction in the pro-inflammatory cytokines interleukin(IL-1α),IL-1β,IL-6,tumor necrosis factorα,and inducible nitric oxide synthase.Our results suggest that argon reduced the extent of inflammation in retinal neurons after ischemia/reperfusion injury by suppression of transcription factors crucial for microglial activation.argon has no known side effects or na

关键词： argon ischemia/reperfusion injury microglia neuroinflammation neuroprotection noble gas SH-SY5Y toll-like receptor transcription factor

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Characteristics of emissive spectrum and the removal of nitric oxide in N_2/O_2/NO plasma with argon additive

引用

Journal of Environmental Sciences 2009年第6期21卷 790-794页

作者： LIN Wenfeng,ZHANG Bin,HOU Wenhui,LI Dawei,YANG Hongmin School of Power Engineering,Nanjing Normal University,Nanjing 210042,China School of Power Engineering Nanjing Normal University Nanjing 210042 China. E-mail: booboo.ai@***

Although the approach using non-thermal plasma（NTP） for deNOx has been studied for over 15 years,how to achieve higher removal effciency with lower cost is still a barrier for its industrial application.In order to investigate the impact of the argon additive on electron density,energy and nitric oxide reduction process in plasma,the spectrum of the dielectric barrier discharge at atmospheric pressure in a coaxial reactor was measured using the monochromater with high resolution.The comparative experiments for NO reduction were carried out simultaneously in N2/O2/NO plasma stream with and without argon,respectively.The nitrogen molecular spectrum which is attributed to the energy level transition（C^3πu→ B^3πg） was compared in the wavelength range 300-480 nm and the electron density and temperature were determined based on the relative intensities and Stark broadening width of spectral lines.The spectrum results indicated that the argon additive could enhance the intensity of emissive spectrum of plasma,thus the electron concentration as well as the energy was increased,and finally prompted the ionization rate to produce active N,O and O3.The results of NO reduction showed that NO conversion effciency increased in the range of 10%-30% with 5% addition of argon in stream comparing with the condition without argon additive.This study will play a positive role in the industrial application of dielectric barrier discharge deNOx reactor.

关键词： argon emissive spectrum nitric oxide non-thermal plasma

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Saturation characteristics of low voltage ionization chamber filled with argon or xenon

引用

Plasma Science and Technology 2022年第6期24卷 57-64页

作者：李超智胡立群张继宗陈开云 Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031People's Republic of China University of Science and Technology of China Hefei 230026People's Republic of China

argon and xenon are both attractive working gas for low voltage ionization chamber(LVIC),which is a promising candidate for ITER X-ray detectors.In this work,the performances of Arfilling LVIC(Ar-LVIC)and Xe-filling LVIC(Xe-LVIC)as well as the impacts of operation parameters were investigated.Saturation curves of Ar-LVIC and Xe-LVIC with pressure from 0.4 to 1.2 bar were measured with a tungsten X-ray source.The minimum voltage of saturation region(V_(min))of Ar-LVIC and Xe-LVIC,the relationship between V_(min)and saturation current,the ideal operating voltage in ITER and impacts of pressure on saturation current were studied.It was found that Ar-LVIC had smaller V_(min)and saturation currents which decreased with the drop of pressure from 1.2 to 0.4 bar;Xe-LVIC had larger V_(min)and saturation currents which did not obviously decrease with the same pressure drop.It is envisaged that ITER can take advantage of the larger saturation current and lower pressure of Xe-LVIC in the non-nuclear operation phase,and flexibility of pressure and low sensitivity to neutron/gamma radiation of Ar-LVIC in the nuclear operation phase.

关键词： low voltage ionization chamber argon xenon saturation curve ITER

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The Radiation Loss of a Cylindrical Methane-argon Plasma Arc

引用

Plasma Science and Technology 2010年第2期12卷 218-223页

作者： B.LIANI R.BENALLAL M.LEMERINI Theoretical Physics Laboratory Sciences Faculty University of Tlemcen

Calculation of the net radiation emitted by a CH4-Ar mixture, in a temperature range of 5,000-30,000 K with the assumption of local thermodynamic equilibrium （LTE）, is conducted. Continuum and line emissions are taken into account. The radiative transfer of each line is calculated by means of an escape factor depending on the shape and broadening of the line. Assuming a cylindrical, homogeneous, and isothermal plasma, the net emission coefficient is calculated for different pressures between 1 atm and 10 atm and arc radia of 0 mm to 1 mm. Results show that the argon presence in the CH4-Ar mixture has a significant effect on the total radiation emitted for the temperature above 17,000 K and the results for pure argon agree with those of BAUDER and EVANS.

关键词： thermal plasma methane argon radiation loss radiative transfer equation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Acute bleeding after argon plasma coagulation for weight regain after gastric bypass: A case report

引用

World Journal of Clinical Cases 2019年第15期7卷 2038-2043页

作者： Diogo Turiani Hourneaux de Moura Amit H Sachdev Po-Wen Lu Igor Braga Ribeiro Christopher C Thompson Division of Gastroenterology Hepatology and EndoscopyBrigham and Women’s HospitalHarvard Medical SchoolBostonMA 02115United States Department of Gastroenterology Clinics Hospital of Sao Paulo UniversitySao Paulo 05403-00Brazil Department of Gastroenterology and Hepatology Linkou Chang Gung Memorial HospitalTaoyuan City33305Taiwan

Roux-en-Y gastric bypass(RYGB)is the most commonly performed surgical procedure used to treat obesity worldwide.Despite satisfactory results in terms of weight loss,over time many patients experience weight regain.There are many factors that contribute to weight regain after RYGB,including the diameter of the gastric-jejunal anastomosis(GJA).One of the most commonly performed endoscopic procedures for weight regain after RYGB is argon plasma coagulation(APC).We report a case of hematemesis after outlet revision with APC.We highlight several treatment modalities that can be used to treat this complication.CASE SUMMARY A 45-year-old female with a history of weight regain after RYGB was referred for possible endoscopic treatment for weight regain.On endoscopic evaluation,the diameter of the GJA was 22 mm.Due to the dilated GJA,treatment with APC was performed.Several months later she reported a return of poor satiety and an increased appetite.A repeat endoscopy was then performed.The GJA was approximately 15 mm and was incompetent.APC was performed.One day post procedure she had four episodes of hematemesis.An endoscopy was performed and a large ulcer with a visible arterial vessel was visualized at the GJA.Coagulation was attempted using a Coagrasper and after initial contact with the vessel,the vessel started oozing.Due to fibrosis and the depth of ulceration in the area,clips and repeat APC could not be used.Therefore,an attempt to inject epinephrine injection was made.However,persistent oozing was noted.As a result,hemostatic powder was applied to the region of the bleeding vessel.Subsequently,no more bleeding was observed.On follow-up,the patient remained hemodynamically stable and a second look endoscopy was not performed.The patient was discharged three days later.CONCLUSION APC revision of the GJA is known to be a relatively safe and effective strategy to manage weight regain post RYGB.Anastomotic site bleeding is an infrequent and potentially life-threatening complication associated with this therapy.Endosc

关键词： Anastomosis Roux-en-Y argon plasma coagulation

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High-power microwave propagation properties in the argon plasma array

引用

Plasma Science and Technology 2019年第1期21卷 44-51页

作者：刘洋时家明程立汪家春袁忠才陈宗胜 State Key Laboratory of Pulsed Power Laser Technology National University of Defense Technology

The argon plasma induced by the L-/C-band high-power microwave(HPM) is investigated theoretically and experimentally. Influences of the microwave power, pulse width, polarization and the plasma electron density on the protection performance of the plasma array against HPM are studied. The results show that the effect of HPM is caused by energy accumulation, with the gas breakdown emerging only after a short time. The attenuation of the wave by the plasma array with the tubes off can reach approximately 23 dB at 1.3 GHz. It can also be obtained that the protection performance of the plasma array against the TE wave is better than that against the TM one. The plasma array shows better protection performance in the L-band than in the C-band. In addition,the attenuation of 5.6 GHz HPM can reach 30 dB when the tubes are turned on in the experiment.The research shows that the plasma array has protection ability against HPM.

关键词： high-power microwave plasma array argon breakdown protection performance experiment

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The dynamics of a nanosecond gas discharge development with an extended slot cathode in argon

引用

Plasma Science and Technology 2020年第12期22卷 78-88页

作者： N A ASHURBEKOV K O IMINOV G S SHAKHSINOV M Z ZAKARYAEVA K M RABADANOV Dagestan State University Faculty of PhysicsMakhachkala 367000Russia Institute of Physics DFRC of RASMakhachkala 367015Russia

The article presents the results of an experimental study and numerical modelling for the formation and development dynamics of a high-voltage transverse nanosecond discharge generated by a slot cathode in an argon medium at a pressure range of 1–10 Torr. Numerical modelling was carried out under similar experimental conditions for the processes of formation and propagation of ionisation waves, electron density distribution, excited atom and average electron energy in the discharge gap, including the cavity inside the cathode. At a pressure of p=1 Torr, a classical version of a high-voltage discharge is demonstrated to take place with no penetration of the plasma into the cathode cavity and no observed hollow cathode effect. An increase in gas pressure to 5 Torr leads to a penetration of plasma into the cathode cavity with the formation of a cathodic potential drop(CPD) region. Electrons emitted from the side surfaces of the cavity pass through the CPD region without collisions, oscillate inside the cathode cavity;the hollow cathode effect is fully manifested. At р=10 Torr, the modelling results qualitatively coincide with the results at р=5 Torr;in this case, however, hardly any accelerated electrons are observed in the gap between the electrodes, due to their energetic relaxation both inside the cathode cavity and when exiting from it. In both cases, the plasma structure formed at the exit of the cathode cavity involves a concentration of charged particles an order of magnitude higher than that in the rest of the gap, leading to a self-limiting discharge current effect. The results of the numerical modelling are in good agreement with experimental data.

关键词： nanosecond gas discharge numerical simulation argon excited atoms

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Efficacy and complications of argon plasma coagulation for hemorrhagic chronic radiation proctitis

引用

World Journal of Gastroenterology 2019年第13期25卷 1618-1627页

作者： Qing-Hua Zhong Zhan-Zhen Liu Zi-Xu Yuan Teng-Hui Ma Xiao-Yan Huang Huai-Ming Wang Dai-Ci Chen Jian-Ping Wang Lei Wang Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases Sun Yat-sen University Department of Colorectal Surgery the Sixth Affiliated Hospital Sun Yat-sen University Guangdong Institute of Gastroenterology

BACKGROUND Chronic radiation proctitis(CRP) is a complication which occurs in 1%-5% of patients who undergo radiotherapy for pelvic malignancies. Although a wide range of therapeutic modalities are available, there is no literature to date showing any particularly appropriate therapeutic modality for each disease stage. argon plasma coagulation(APC) is currently recommended as the firstchoice treatment for hemorrhagic CRP, however, its indication based on longterm follow-up is still unclear. On the hypothesis that the long-term efficacy and safety of APC are not fully understood, we reviewed APC treatment for patients with hemorrhagic CRP from a single center.AIM To assess the long-term efficacy and safety of APC for hemorrhagic CRP.METHODS This is a retrospective study of consecutive patients treated with APC for hemorrhagic CRP from January 2013 to October 2017. Demographics, clinical variables, and typical endoscopic features were recorded independently. Success was defined as either cessation of bleeding or only occasional traces of bloody stools with no further treatments for at least 12 mo after the last APC treatment.We performed univariate and multivariate analyses to identify factors associated with success and risk factors for fistulas.RESULTS Forty-five patients with a median follow-up period of 24 mo(range: 12-67 mo)were enrolled. Fifteen(33.3%) patients required blood transfusion before APC.Successful treatment with APC was achieved in 31(68.9%) patients. The mean number of APC sessions was 1.3(1-3). Multivariate analysis showed that APC failure was independently associated with telangiectasias present on more than50% of the surface area [odds ratio(OR) = 6.53, 95% confidence interval(CI): 1.09-39.19, P = 0.04] and ulcerated area greater than 1 cm^2(OR = 8.15, 95%CI: 1.63-40.88, P = 0.01). Six(13.3%) patients had severe complications involving rectal fistulation. The only factor significantly associated with severe complications was ulcerated area greater than 1 cm^2(P = 0.035).CONCLUSION The long-te

关键词： argon plasma coagulation Chronic radiation proctitis Radiation proctopathy Efficacy Safety

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：