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Analysis of the Efficacy of High-Flow Nasal Cannula Oxygen Therapy and Non-Invasive Ventilation in COPD Patients
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作者 Xue Yin Yan Li +6 位作者 Yan Ma Yue Sun Li Li Wenmei Yan Jianhua Zhang He Zhang Haisheng Yang 《Journal of Clinical and Nursing Research》 2025年第11期307-315,共9页
Patients with acute exacerbation of chronic obstructive pulmonary disease(COPD)often suffer from respiratory failure and require respiratory support therapy.High-flow nasal cannula oxygen therapy(HFNC)and non-invasive... Patients with acute exacerbation of chronic obstructive pulmonary disease(COPD)often suffer from respiratory failure and require respiratory support therapy.High-flow nasal cannula oxygen therapy(HFNC)and non-invasive positive pressure ventilation(NIPPV)are commonly used non-invasive respiratory support methods.HFNC can provide precisely heated and humidified high-flow oxygen,reducing dead space and increasing alveolar ventilation.NIPPV can supply stable high-concentration oxygen and improve gas exchange.This article reviews the application of HFNC and NIPPV in the acute exacerbation stage of COPD,aiming to provide references for reasonable clinical selection. 展开更多
关键词 Chronic obstructive pulmonary disease high-flow nasal cannula oxygen therapy Non-invasive ventilation Acute exacerbation stage
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High-flow nasal cannula oxygen therapy and noninvasive ventilation for preventing extubation failure during weaning from mechanical ventilation assessed by lung ultrasound score: A single-center randomized study 被引量:12
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作者 Shan-xiang Xu Chun-shuang Wu +1 位作者 Shao-yun Liu Xiao Lu 《World Journal of Emergency Medicine》 SCIE CAS CSCD 2021年第4期274-280,共7页
BACKGROUND: We sought to demonstrate the superiority of a targeted therapy strategy involving high-flow nasal cannula oxygen(HFNCO_(2)) therapy and noninvasive ventilation(NIV) using lung ultrasound score(LUS) in comp... BACKGROUND: We sought to demonstrate the superiority of a targeted therapy strategy involving high-flow nasal cannula oxygen(HFNCO_(2)) therapy and noninvasive ventilation(NIV) using lung ultrasound score(LUS) in comparison with standard care among patients in the intensive care unit(ICU) who undergo successful weaning to decrease the incidence of extubation failure at both 48 hours and seven days.METHODS: During the study period, 98 patients were enrolled in the study, including 49 in the control group and 49 in the treatment group. Patients in the control group and patients with an LUS score <14 points(at low risk of extubation failure) in the treatment group were extubated and received standard preventive care without NIV or HFNCO_(2). Patients with an LUS score ≥14 points(at high risk of extubation failure) in the treatment group were extubated with a second review of the therapeutic optimization to identify and address any persisting risk factors for postextubation respiratory distress;patients received HFNCO2 therapy combined with sessions of preventive NIV(4-8 hours per day for 4-8 sessions total) for the first 48 hours after extubation.RESULTS: In the control group, 13 patients had the LUS scores ≥14 points, while 36 patients had scores <14 points. In the treatment group, 16 patients had the LUS scores ≥14 points, while 33 patients had scores <14 points. Among patients with the LUS score ≥14 points, the extubation failure rate within 48 hours was 30.8% in the control group and 12.5% in the treatment group, constituting a statistically significant difference(P<0.05). Conversely, among patients with an LUS score <14 points, 13.9% in the control group and 9.1% in the treatment group experienced extubation failure(P=0.61). The length of ICU stay(9.4±3.1 days vs. 7.2±2.4 days) was significantly different and the re-intubation rate(at 48 hours: 18.4% vs. 10.2%;seven days: 22.4% vs. 12.2%) significantly varied between the two groups(P<0.05). There was no significant difference in the 28-day mortality rate(6.1% vs. 8.2%) between the control and treatment groups.CONCLUSIONS: Among high-risk adults being weaned from mechanical ventilation and assessed by LUS, the NIV+HFNCO_(2) protocol does not lessen the mortality rate but reduce the length of ICU stay, the rate of extubation failure at both 48 hours and seven days. 展开更多
关键词 high-flow nasal cannula oxygen Noninvasive ventilation Lung ultrasound EXTUBATION
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Statistical modelling for effect of mix-parameters on properties of high-flowing sand-concrete 被引量:7
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作者 T.BOUZIANI A.BENMOUNAH M.BDRINA 《Journal of Central South University》 SCIE EI CAS 2012年第10期2966-2975,共10页
The high-flowing sand-concrete (HFSC) containing natural sands as aggregate was carried out. The high fluidity and stability of HFSC can be achieved by tailoring the mix design parameters, such as fine to coarse san... The high-flowing sand-concrete (HFSC) containing natural sands as aggregate was carried out. The high fluidity and stability of HFSC can be achieved by tailoring the mix design parameters, such as fine to coarse sand ratio, dosage of additions, water to binder ratio and dosage of admixtures. Mini-cone slump test, v-fl.mnel time test and viscosity model parameters were used to characterize the behaviour of HFSC in fresh state. The mechanical compressive strength in 28 d was also determined. A factorial design approach was used to establish models highlighting the effect of each mix-parameter on measured properties of HFSC. The derived models are valid for mixtures made with 0 to 0.3 of dune sand to total sand ratio, 82 to 418 kg/m3 of marble powder, 0.42 to 0.46 of water/binder ratio and 1.3% to 1.9% of superplasticizer high water-reducer. The results show that the derived models constitute very efficient means for understanding the influence of key mix-parameters on HFSC properties and are useful in selecting the optimum mix proportions, by simulating their impact on fluidity, stability and compressive strength. 展开更多
关键词 high-flowing sand-concrete factorial design FLUIDITY VISCOSITY mix-design parameters
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Influence of fly ash on early-age cracking behavior of high-flowing concrete 被引量:5
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作者 郑建岚 王雪芳 《Journal of Central South University》 SCIE EI CAS 2009年第2期312-319,共8页
The effects of quality and content of fly ash on the early-age cracking behavior of high-flowing concrete (HFC) were investigated. The early-age cracking behavior of the HFC was analyzed by combining the tests of ev... The effects of quality and content of fly ash on the early-age cracking behavior of high-flowing concrete (HFC) were investigated. The early-age cracking behavior of the HFC was analyzed by combining the tests of evaporation capacity and electrical resistivity of the HFC. In these tests, a modified flat-type specimen was adopted. The results show that the HFC will have a lower evaporation capacity when it is mixed with fine fly ash, while it will have a higher evaporation capacity when grade II! fly ash is used as mineral admixture. And the electrical resistivity rate of HFC reduces with the increase of the content of fly ash. A nonlinear relationship exists between the cracking time of HFC and the minimum electrical resistivity. The early-age cracking behavior of HFC with fly ash can be enhanced by appropriately increasing the fine particle content and MgO, K2O, and SO3 contents of fly ash. The optimal content of fly ash, which makes a satisfied early-age cracking behavior of HFC, is obtained. And when the content of fly ash exceeds a critical value, the early-age cracking behavior of HFC will rapidly decrease. 展开更多
关键词 high-flowing concrete fly ash cracking behavior electrical resistivity
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Design and Experiment-Based Optimization of High-Flow Hydraulic One-Way Valves 被引量:4
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作者 Lei Liu Ping Yu 《Fluid Dynamics & Materials Processing》 EI 2020年第2期211-224,共14页
High-flow hydraulic one-way valves in water pipes are typically used to mitigate conditions,which would otherwise cause vibration and cavitation erosion after long-term operation.To prevent cavitation and enhance the ... High-flow hydraulic one-way valves in water pipes are typically used to mitigate conditions,which would otherwise cause vibration and cavitation erosion after long-term operation.To prevent cavitation and enhance the performance of hydraulic one-way valves,in the present work a dedicated experimental study has been conducted.The structural parameters relating to the pilot valve core,the main valve core,and the through-flow section of the considered flow channel have been changed to analyse reverse impact,and cavitation,characteristics.The results show that the control pressure has a weak effect on the cavitation characteristics,while changes in the structural parameters can significantly affect them.In particular,the cavitation index,representing the extent of cavitation,has been found to display a linear correlation with the inlet pressure,but,not with the inlet flow rate.Most importantly,a stepped throttling structure can reduce the pressure oscillation,improve the response speed,enhance the impact characteristics,and decrease the likelihood and severity of cavitation.The larger the flow passage area,the shorter the unloading time.Cavitation mainly occurs when the pilot valve core is fully opened.The stepped main valve core throttling structure has been found to be an optimal option. 展开更多
关键词 high-flow structural design IMPACT CAVITATION
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Dynamic characteristics of the high-flow water three-way valve 被引量:2
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作者 Chuan-Li WANG Xia GAO Hai-Shun DENG Yu HUANG 《Journal of Coal Science & Engineering(China)》 2013年第3期392-395,共4页
Operating principle of water three-way valve with high flow for individual hydraulic prop in coal was presented in this paper, its strict and precise mathematical model was established, its flow field was simulated nu... Operating principle of water three-way valve with high flow for individual hydraulic prop in coal was presented in this paper, its strict and precise mathematical model was established, its flow field was simulated numerically by software Fluent, and its dynamic characteristics were analyzed during the work process such as raising leg, loading and overflow, the influence of the related parameters on high-flow water three-way valve was determined. The results as follows: during the raising leg stage and early raising leg stage, when the damping ratio increases, the overshoot of system decreases and the setting time reduces, and the dynamic response performance has a significant improvement. During the loading stage and the overflow stage, the pressure in plunger chamber of single hydraulic prop, the output flow and the displacement of the high-flow water three-way valve decrease with the decreasing of the external load. The spring stiffness of the safety valve directs the flow and the spool's displacement of the safety valve, and it can be used to control the high-flow three-way valve's sensitivity. 展开更多
关键词 high-flow three-way valve water hydraulic structural design dynamic characteristics
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Sleep Quality for Patients Receiving Noninvasive Positive Pressure Ventilation and Nasal High-Flow Oxygen Therapy in an ICU: Two Case Studies 被引量:1
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作者 Hiroaki Murata Yoko Yamaguchi 《Open Journal of Nursing》 2018年第9期605-615,共11页
Aim: The purpose of this case study was to examine the sleep quality of patients receiving noninvasive positive pressure ventilation (NPPV) or nasal high-flow oxygen therapy (NHF) in an intensive care unit and to inve... Aim: The purpose of this case study was to examine the sleep quality of patients receiving noninvasive positive pressure ventilation (NPPV) or nasal high-flow oxygen therapy (NHF) in an intensive care unit and to investigate what types of nursing support are offered to such patients. Methods: We examined one patient each for NPPV and NHF. Polysomnography (PSG), review of the patient charts, and semi-structured interviews were used to collect the data for analysis. Results: Patients treated with NPPV or NHF demonstrated a noticeable reduction in deep sleep, with most of their sleep being shallow. Their sleep patterns varied greatly from those of healthy individuals. These results suggest that, in addition to experiencing extremely fragmented sleep, sleep in these patients was more likely to be interrupted by nursing interventions, such as during auscultation of breath sounds. Furthermore, it was revealed that “anxiety or discomfort that accompanies the mask or air pressure” in patients treated with NPPV and “discomfort that accompanies the nasal cannula or NHF circuit” in patients treated with NHF may be primary causes of disrupted sleep. Our results suggest a need for nursing care aimed at improving sleep quality in patients treated with NPPV or NHF. 展开更多
关键词 Noninvasive Positive Pressure Ventilation (NPPV) NASAL high-flow Oxygen Therapy (NHF) Sleep DEPRIVATION ICU Post Intensive Care Syndrome (PICS)
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Efficacy of high-flow nasal cannula on acute exacerbation of chronic obstructive pulmonary disease: A meta-analysis 被引量:1
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作者 Ying-Ming Sun Min Zhang +2 位作者 Na Sun Zhi Guan Ying Wang 《Medical Data Mining》 2019年第4期142-149,共8页
Objective:To systematically evaluate the efficacy and feasibility of high-flow nasal cannula(HFNC)on patients with acute exacerbation of chronic obstructive pulmonary disease(AECOPD).Methods:Systematic searches on Pub... Objective:To systematically evaluate the efficacy and feasibility of high-flow nasal cannula(HFNC)on patients with acute exacerbation of chronic obstructive pulmonary disease(AECOPD).Methods:Systematic searches on PubMed,Web of Science,the Cochrane Library,Embase,CBM(Chinese Biomedicine Database),CNKI(China National Knowledge Infrastructure),Wanfang Database and VIP were performed for randomized controlled trials(RCTs)which explored the effects of HFNC on patients with AECOPD.The retrieval time was from the establishment of each database to July 2019.RevMan5.3 software was used for statistical analysis.Results:A total of 12 articles were included,involving 812 patients.The results showed that:(1)Compared with conventional oxygen therapy,HFNC could improve patients'arterial partial oxygen pressure(PaO2)(MD=12.70,95%CI(7.00,18.40),Z=4.37,P<0.0001),reduce partial arterial blood carbon dioxide(PaCO2)(MD=-10.99,95%CI(-14.42,-7.55),Z=6.26,P<0.00001)and reduce endotracheal intubation rate(OR=0.19,95%CI(0.04,0.93),Z=2.05,P=0.04),shorten the hospitalization time(SMD=-0.74,95%CI(-1.11,-0.37),Z=3.95,P<0.0001).(2)Compared with non-invasive positive pressure ventilation,it has fewer adverse reactions(OR=0.18,95%CI(0.09,0.35),Z=5.08,P<0.00001)and shorter hospital stay(SMD=-0.57,95%CI(-0.90,-0.23),Z=3.33,P=0.0009).Conclusion:HFNC can improve the patients’hypoxia symptoms and CO2 retention,reduce the rate of tracheal intubation,and alleviate adverse reactions.However,Limited by the quality and region of the included studies,more high-quality are needed to test it. 展开更多
关键词 high-flow nasal cannula AECOPD Non-invasive positive pressure ventilation Conventional oxygen therapy META-ANALYSIS
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Prone position combined with high-flow nasal oxygen could benefit spontaneously breathing, severe COVID-19 patients:A case report
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作者 Da-Wei Xu Guang-Liang Li +1 位作者 Jiong-Han Zhang Fei He 《World Journal of Clinical Cases》 SCIE 2021年第17期4381-4387,共7页
BACKGROUND Since the outbreak of coronavirus disease 2019(COVID-19)in Wuhan,China in December 2019,the overall fatality rate of severe and critical patients with COVID-19 is high and the effective therapy is limited.C... BACKGROUND Since the outbreak of coronavirus disease 2019(COVID-19)in Wuhan,China in December 2019,the overall fatality rate of severe and critical patients with COVID-19 is high and the effective therapy is limited.CASE SUMMARY In this case report,we describe a case of the successful combination of the prone position(PP)and high-flow nasal oxygen(HFNO)therapy in a spontaneously breathing,severe COVID-19 patient who presented with fever,fatigue and hypoxemia and was diagnosed by positive throat swab COVID-19 RNA testing.The therapy significantly improved the patient's clinical symptoms,oxygenation status,and radiological characteristics of lung injury during hospitalization,and the patient showed good tolerance and avoided intubation.Additionally,we did not find that medical staff wearing optimal airborne personal protective equipment(PPE)were infected by the new coronavirus in our institution.CONCLUSION We conclude that the combination of PP and HFNO could benefit spontaneously breathing,severe COVID-19 patients.The therapy does not increase risk of healthcare workers wearing optimal airborne PPE to become infected with virus particles. 展开更多
关键词 COVID-19 HYPOXEMIA high-flow nasal oxygen Intubation and prone position Case report
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Efficacy and Safety of Treatment of High-flow Priapism with Superselective Transcatheter Embolization
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作者 Tao QI Lei YE +5 位作者 Zheng CHEN Zhan-sen HUANG Bo WANG Hao LI Bin ZHANG Jun CHEN 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2018年第1期101-106,共6页
This study is aimed to evaluate the effectiveness and safety of the treatment of highflow priapism with superselective transcatheter embolization.From Sep.1999 to Jan.2013,six patients with high-flow priapism underwen... This study is aimed to evaluate the effectiveness and safety of the treatment of highflow priapism with superselective transcatheter embolization.From Sep.1999 to Jan.2013,six patients with high-flow priapism underwent superselective transcatheter embolization of the cavernous artery.Recurrence of priapism,and change in erectile function detected by nocturnal penile tumescence and rigidity(NPTR)test and the International Index of Erectile Function 5-item questionnaire(IIEF-5)were evaluated during a mean follow-up of 12 months.A single superselective transcatheter embolization was sufficient for complete resolution of priapism in the six patients.None of the patients had a relapse of priapism after embolization,and all the patients who had premorbid normal erectile function showed maintained potency with normal results of NPTR and a mean postoperative IIEF-5 score of 23.5(range 23 to 24)during the follow-up period.In conclusion,superselective transcatheter embolization is an effective and safe treatment method for high-flow priapism,and it can ensure a high level of preservation of premorbid erectile function. 展开更多
关键词 high-flow priapism superselective transcatheter embolization
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Analysis of the Efficacy of Humidified High-Flow Nasal Oxygen Therapy Combined with Alveolar Lavage in the Treatment of Patients with Severe Pneumonia Complicated with Respiratory Failure
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作者 Lianyu Zhang 《Journal of Clinical and Nursing Research》 2023年第3期112-117,共6页
Objective:To analyze the curative effect of humidified high-flow nasal oxygen therapy combined with alveolar lavage in patients with severe pneumonia and respiratory failure.Methods:120 patients with severe pneumonia ... Objective:To analyze the curative effect of humidified high-flow nasal oxygen therapy combined with alveolar lavage in patients with severe pneumonia and respiratory failure.Methods:120 patients with severe pneumonia complicated with respiratory failure admitted to the Third People’s Hospital of Xining from July 2021 to December 2022 were randomly divided into two groups:group A and group B.The patients in group A were given humidified high-flow nasal oxygen therapy combined with alveolar lavage,whereas those in group B were given humidified high-flow nasal oxygen therapy.The treatment efficacy,blood gas analysis results,and differences in inflammatory mediators were compared between the two groups.Results:The curative effect in group A(96.67%)was significantly higher than that in group B(81.67%),P<0.05;the partial pressure of carbon dioxide(PaCO2),partial pressure of oxygen(PaO2),oxygen saturation(SpO2),and Horowitz index(P/F)of group A were significantly better than group B,P<0.05;the interleukin 6(IL-6),tumor necrosis factor alpha(TNF-α),and C-reactive protein(CRP)levels,white blood cell(WBC)count,serum procalcitonin(PCT),and neutrophil(N)percentage of group A were significantly lower than those of group B,P<0.05.Conclusion:For patients with severe pneumonia complicated with respiratory failure,alveolar lavage,on the basis of humidified high-flow oxygen therapy,can inhibit local inflammation,improve blood gas analysis results,promote disease recovery,and improve the clinical treatment effect。 展开更多
关键词 Alveolar lavage high-flow oxygen therapy Humidified nasal oxygen therapy Severe pneumonia Respiratory failure
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智能井流量控制系统高温电磁阀结构优化设计 被引量:5
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作者 郑严 顿志强 +3 位作者 王晓 王龙 钟俊宇 马传钦 《液压与气动》 北大核心 2025年第3期50-60,共11页
井下流量控制系统作为智能完井系统的核心部件,对井下智能开采至关重要,而井下高温电磁阀作为电控液驱流量控制系统的重要元件,对控制系统性能起到关键作用。介绍了电磁阀结构及工作原理,利用有限元仿真建立电磁铁模型,分析了电磁铁静... 井下流量控制系统作为智能完井系统的核心部件,对井下智能开采至关重要,而井下高温电磁阀作为电控液驱流量控制系统的重要元件,对控制系统性能起到关键作用。介绍了电磁阀结构及工作原理,利用有限元仿真建立电磁铁模型,分析了电磁铁静铁芯锥角、静铁芯凸台、线圈位置、隔磁环倾角、隔磁环长度对电磁力特性影响,并进行了电磁-热耦合仿真分析。采用正交试验设计研究影响电磁力结构参数之间的主次关系,并基于响应面法与改进粒子群算法结合的优化思路,对电磁铁结构参数进行优化设计。优化后0 mm处的电磁力提高了16.68%,0.5 mm处电磁力提高了29.62%,1 mm处电磁力提高了31.06%,为电控液驱型流量控制系统设计奠定了理论基础。 展开更多
关键词 智能井 流量控制系统 高温电磁阀 正交试验 改进粒子群算法
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油麦兼用高速播种机气送式排肥系统设计与试验
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作者 廖宜涛 武安阳 +3 位作者 廖庆喜 郑娟 王传奇 张青松 《农业机械学报》 北大核心 2025年第7期60-71,共12页
针对外槽轮排肥器在高速作业中存在肥料供应不足、脉动断条,造成肥料连续性、均匀性不足等问题,设计了一种叶轮供肥、离心分肥、辅以气流输送的气送式高速排肥系统。对叶轮供肥装置结构、离心分肥装置导流头和凹面圆盘进行设计;通过EDE... 针对外槽轮排肥器在高速作业中存在肥料供应不足、脉动断条,造成肥料连续性、均匀性不足等问题,设计了一种叶轮供肥、离心分肥、辅以气流输送的气送式高速排肥系统。对叶轮供肥装置结构、离心分肥装置导流头和凹面圆盘进行设计;通过EDEM仿真试验,验证了所设计的叶轮供肥装置供肥变异系数小于3.2%,明确了导流头曲线为带摩擦最速降线时肥料颗粒流速最快,确定了直线型、二次多项式曲线型、三次多项式曲线型3种凹面圆盘曲线的最优结构参数;开展3种曲线结构的凹面圆盘台架试验,确定直线型凹面圆盘作业效果最优。以仿真确定的供肥装置、带摩擦最速降线导流头和直线型凹面圆盘开展叶轮转速与离心圆盘转速工作参数匹配试验,结果表明,在各行排肥量一致性变异系数低于7%条件下,当叶轮转速为14.00~21.23 r/min即前进速度为9.00~10.24 km/h时,离心圆盘转速应大于168.2 r/min;当叶轮转速为21.23~25.00 r/min即前进速度为10.24~12.00 km/h时,离心圆盘转速应小于150 r/min。田间性能验证试验结果表明,在较优匹配工作参数下排肥系统总排肥量稳定性变异系数均不大于4.11%,各行排肥量稳定性变异系数均不大于6.94%。该研究为油麦兼用高速播种机高速施肥装置设计提供了参考。 展开更多
关键词 气送式排肥系统 油麦兼用高速播种机 导流头 离心分肥装置 EDEM
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油口串联式双输出动力源输出流量与能效特性仿真研究 被引量:1
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作者 潘之杰 武瀚文 +2 位作者 耿怀德 解松涛 权龙 《液压与气动》 北大核心 2025年第6期1-8,共8页
针对高压液压泵国产化替代难的技术难题,提出一种油口串联式双输出动力源的设计形式并开展研究。该方案通过在第一级泵的出油口处串联第二级泵,实现逐级加压,无需改造低性能泵即可实现高压需求。串联结构显著降低了单泵压差,延长使用寿... 针对高压液压泵国产化替代难的技术难题,提出一种油口串联式双输出动力源的设计形式并开展研究。该方案通过在第一级泵的出油口处串联第二级泵,实现逐级加压,无需改造低性能泵即可实现高压需求。串联结构显著降低了单泵压差,延长使用寿命,并通过蓄能器隔离负载冲击。通过SimulationX仿真,分析了油口串联式双输出动力源流量脉动性能和驱动高低压负载的能效性能,结果表明:在20 MPa、1500 r/min工况下,与单级齿轮泵相比,其流量脉动率降低37%;单级变量轴向柱塞泵驱动高低压负载液压缸的系统能效为36%,将动力源换为油口串联式双输出动力源后,系统能效提升到61%。研究结果为复杂高压液压系统的动力源设计提供了新思路。 展开更多
关键词 双液压泵油口串联 流量脉动 能效优化 高压液压系统
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高空台管网系统流动参数的变化规律与相关性分析
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作者 陈律江 张健平 +3 位作者 张松 但志宏 聂博文 杨豪 《大学物理实验》 2025年第2期80-91,共12页
针对目前高空台模拟系统将两调节阀间的管道作为1个控制模型致使控制精度低的问题,采用Fluent软件分析了管径、进口段长度、出口段长度和弯头类型对高空台管网系统流动参数的影响。结果表明:管径、进口段长度和弯头类型对流动参数影响较... 针对目前高空台模拟系统将两调节阀间的管道作为1个控制模型致使控制精度低的问题,采用Fluent软件分析了管径、进口段长度、出口段长度和弯头类型对高空台管网系统流动参数的影响。结果表明:管径、进口段长度和弯头类型对流动参数影响较大,管径和进口段长度增加,流动参数变化减小,且45°弯头流动参数变化大于90°弯头。此外,管径增加,进口段突变位置对应的管道长度系数为0.8~0.9,45°弯头出口段突变位置约为0.1,90°弯头出口段突变位置约为0.15~0.27。进口段长度增加,进口段突变位置约为0.35~0.95,45°弯头出口段突变位置约为0.05~0.084,90°弯头出口段突变位置约为0.1。而出口段长度增加,只会影响出口段突变位置,约为0.04~0.44。在此基础上,通过斯皮尔曼相关性分析获得影响进、出口段突变位置的主次顺序为进口段长度>管径>出口段长度>弯头类型,出口段长度>管径>弯头类型>进口段长度。 展开更多
关键词 高空台 管网系统 流动参数 变化规律 相关性分析
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高矿化度矿井水深井回灌驱动下地下水流场演化与突水风险模拟 被引量:1
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作者 刘琪 孙亚军 +5 位作者 范建国 谭现锋 肖圣新 杨传伟 陈炜阳 陈歌 《煤田地质与勘探》 北大核心 2025年第11期195-208,共14页
【目的】矿井水深井回灌会引起区域地下水水位不同程度抬升,可能诱发底板突水、断层突水等水文地质灾害,厘清矿井水长期回灌驱动下的地下水流场演化规律并开展安全性评价,是实现矿井水安全回灌与保水开采的重要保障。【方法】以华北巨... 【目的】矿井水深井回灌会引起区域地下水水位不同程度抬升,可能诱发底板突水、断层突水等水文地质灾害,厘清矿井水长期回灌驱动下的地下水流场演化规律并开展安全性评价,是实现矿井水安全回灌与保水开采的重要保障。【方法】以华北巨野煤田某矿矿井水为研究对象,在阐明研究区矿井水回灌背景条件下,以回灌安全、水质安全、水循环条件与开发利用、回灌潜力等指标筛选回灌目的层;采用地下水模拟系统(groundwater modeling system,GMS)建立奥陶系灰岩含水层三维数值模型,模拟预测矿井水长期回灌过程中区域地下水水位抬升、累计储水量与回灌效率,并判断水位抬升后可能诱发的主要突水模式。结合《煤矿防治水细则》规程公式与FLAC^(3D)数值模拟结果,评估长期回灌条件下最大水位抬升对安全开采的影响,最终构建矿井水深井回灌的安全评价体系。【结果和结论】(1)研究区矿井涌水量大、矿化度高、水处理成本高,筛选对比后提出深部奥陶系灰岩含水层适宜作为微处理后矿井水回灌目标层,并提出孔位选址依据;(2)GMS模拟结果显示单孔200 m^(3)/h回灌10 a最大水位抬升10.02 m,4孔400 m间距800 m^(3)/h最大水位抬升25.83 m,单孔年回灌量可达172万m^(3),储水潜力巨大且成本优势显著;(3)断层突水为水位抬升条件下研究区最易诱发的突水模式,根据规程公式与FLAC^(3D)模拟结果,在留设满足要求的煤(岩)柱条件下,回灌引起的水位抬升不会破坏隔水岩组的结构稳定性,正常采掘活动难以诱发回灌次生突水,可满足安全开采要求;(4)建立矿井水深井回灌安全评价技术体系,提出矿井水深井回灌技术满足水质安全与开采安全是技术实施的必要条件。研究成果对华北典型水文地质结构矿山开展矿井水回灌安全评价工作具有重要的理论和实践指导价值。 展开更多
关键词 巨野煤田 矿井水回灌 回灌目的层筛选 流场演化 安全性评价体系 高TDS矿井水
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冠状动脉慢血流患者MHR和SII水平变化及诊断意义
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作者 房志琴 马逸平 +6 位作者 梁惠清 李珺 赵坤 张鹏祥 王亚玲 李方江 李萍萍 《中国分子心脏病学杂志》 2025年第1期6602-6607,共6页
目的探讨冠状动脉慢血流(coronary slow flow,CSF)患者和冠状动脉血流正常(normal coronary flow,NCF)患者中单核细胞/高密度脂蛋白胆固醇比(monocyte/high-density lipoprotein cholesterol ratio,MHR)和全身免疫炎症指标(systemic imm... 目的探讨冠状动脉慢血流(coronary slow flow,CSF)患者和冠状动脉血流正常(normal coronary flow,NCF)患者中单核细胞/高密度脂蛋白胆固醇比(monocyte/high-density lipoprotein cholesterol ratio,MHR)和全身免疫炎症指标(systemic immune inflammation index,SII)水平的差异,明确MHR和SII对CSF患者诊断的预测价值。方法随机选取2023年1月至2024年3月因胸痛或胸闷症状于河北北方学院附属第一医院心内科行冠状动脉造影的患者,CSF组40例,NCF组40例。比较两组患者病史及化验指标等基本临床资料。采用二元logistic回归分析研究MHR、SII与CSF患病的关系,采用Pearson相关分析研究MHR、SII与平均心肌梗死溶栓后血流计帧数(mean thrombolysis in myocardial infarction frame count,mTFC)相关性,利用受试者操作特征(receiver operating characteristic,ROC)曲线评估MHR、SII及两者联合对CSF的预测价值。结果与NCF组相比,CSF组MHR[(3.80±1.79)×10^(8)/mmol比(1.28±0.80)×10^(8)/mmol]、SII[(411.6±15.2)×10^(9)/L比(392.7±13.7)×10^(9)/L]及mTFC[(48.03±5.03)帧比(25.83±6.32)帧]均升高(P均<0.05)。Logistic多因素分析提示MHR和SII均为CSF的独立危险因素(OR=4.201,95%CI:1.749~10.092,P=0.001;OR=1.089,95%CI:1.024~1.158,P=0.007)。MHR、SII均与mTFC显著正相关(r=0.407,r=0.445,P均<0.05)。MHR预测CSF的ROC曲线下面积(area under the curve,AUC)为0.901(P<0.001),灵敏度为82.5%,特异度为90.0%,95%CI为0.833~0.969;SII预测CSF的AUC为0.844(P<0.001),灵敏度为82.5%,特异度为77.5%,95%CI为0.757~0.932;两者联合诊断CSF的AUC为0.932(P<0.001),灵敏度为87.5%,特异度为95.0%,95%CI为0.875~0.990。结论与NCF组相比,CSF组MHR和SII水平显著升高,MHR、SII及二者联合对冠状动脉慢血流有较好的预测价值。 展开更多
关键词 冠状动脉慢血流 单核细胞/高密度脂蛋白胆固醇比值 全身免疫炎症指标 诊断价值
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多联机室外机在超高层受限空间布置的散热模拟分析与优化
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作者 江宋标 郭勇 +1 位作者 范济荣 施时雨 《制冷》 2025年第5期40-45,共6页
以广州某超高层建筑为研究对象,通过数值模拟分析风冷变制冷剂流量系统室外机设置于建筑凹槽式受限空间的散热性能。研究模拟了三种典型形式(平台1-E、2-W、2-S),重点分析回风温度、局部热积效应及外部建筑构件对气流组织的影响。结果表... 以广州某超高层建筑为研究对象,通过数值模拟分析风冷变制冷剂流量系统室外机设置于建筑凹槽式受限空间的散热性能。研究模拟了三种典型形式(平台1-E、2-W、2-S),重点分析回风温度、局部热积效应及外部建筑构件对气流组织的影响。结果表明,通过建筑风场和设备散热模型的模拟,分析了不同室外机平台的散热效果,并提出了优化建议。研究结果表明,合理设计室外机平台的进深、优化新风补进路径和选用高停机保护温度的设备,可以有效改善散热效果,确保空调系统的可靠运行。 展开更多
关键词 风冷变制冷剂流量系统 超高层建筑 散热模拟 受限空间优化
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宽温高湿环境下油水两相O形液压杆封性能分析 被引量:2
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作者 王冰清 李晓暄 +3 位作者 彭旭东 李运堂 陈源 金杰 《润滑与密封》 北大核心 2025年第1期1-10,共10页
针对宽温高湿环境下液压油受水污染而使密封处于油包水两相润滑状态,建立油包水流型下油水两相液压杆封热弹流混合润滑模型,探究宽温环境和含水率对油水两相O形液压杆封静力学特性、密封行为及密封性能的影响机制与规律。研究结果表明:... 针对宽温高湿环境下液压油受水污染而使密封处于油包水两相润滑状态,建立油包水流型下油水两相液压杆封热弹流混合润滑模型,探究宽温环境和含水率对油水两相O形液压杆封静力学特性、密封行为及密封性能的影响机制与规律。研究结果表明:在油包水流型下,含水率增大时,油水混合物黏度略增大,流体动压效应增强,净泄漏率减小,摩擦力减小,密封润滑特性及性能均提升;低温环境下,密封挤压变形小,液膜黏度大,流体动压效应强,净泄漏率虽小但摩擦力大;高温环境下,密封挤压变形大,诱发局部应力集中,液膜黏度小,流体动压效应弱,净泄漏率大;环境温度对密封性能影响十分显著,特别是高温高速或高温高压工况下,净泄漏率明显增大。 展开更多
关键词 液压杆封 油水两相流 液压系统 宽温高湿环境 密封性能 静力学特性
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基于高功率密度电动潜水泵的大流量高效移动排涝系统装置设计与验证
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作者 谢德华 陈晓清 +5 位作者 陈东 陈云 杨远见 刘仲秋 王朝 周子阳 《机电工程技术》 2025年第15期175-181,共7页
为解决无固定泵站淹没区及大水域应急排涝场景中设备部署慢、效率低的问题,提出一种基于高功率密度电动潜水泵的大流量高效移动排涝系统。基于高功率密度永磁电机技术(效率97%)、采用轻量化永磁电机结构以及铝合金泵体、泵组结构拓扑优... 为解决无固定泵站淹没区及大水域应急排涝场景中设备部署慢、效率低的问题,提出一种基于高功率密度电动潜水泵的大流量高效移动排涝系统。基于高功率密度永磁电机技术(效率97%)、采用轻量化永磁电机结构以及铝合金泵体、泵组结构拓扑优化技术,设计一种流量大于或等于10 000 m^(3)/h、扬程大于或等于10 m、质量小于或等于3 t、效率大于或等于80%的高效轻量化自浮式泵组;开发专用多功能转移装置实现30°坡道泵组无吊机转运及上下水;通过模块化方舱集成供配电、管路系统(聚氨酯水带加专用轻质化低流阻弯头)及智能监控系统实现了应急排涝的高效作业以及快速部署。通过理论设计分析和样机研制与实地测试,验证了预期的设计目标。实地测试表明:系统流量10 005 m^(3)/h时扬程达10.12 m,管网损耗6.48%,6 h完成部署,满足复杂地形快速响应需求。 展开更多
关键词 高功率密度电动潜水泵 大流量高效移动排涝系统 专用多功能转移装置 方舱
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