期刊文献+
共找到134篇文章
< 1 2 7 >
每页显示 20 50 100
Effect of CO_2 partial pressure on SCC behavior of welded X80 pipeline in simulated soil solution 被引量:3
1
作者 Ming WU Xu CHEN Chuan HE Jun XIAO 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2011年第1期65-74,共10页
The stress corrosion cracking (SCC) behavior of welded X80 pipeline steel in simulated Ku'erle soil solution was studied by means of electrochemical impedance spectroscopy (EIS) and slow strain rate tests (SSRT... The stress corrosion cracking (SCC) behavior of welded X80 pipeline steel in simulated Ku'erle soil solution was studied by means of electrochemical impedance spectroscopy (EIS) and slow strain rate tests (SSRT). The microstructure of the welded steel was observed by optical microscopy (OM). It is demonstrated that the microstructure of the weld metal consists of acicular ferrite and grain boundary ferrite, while that of heat affected zone (HAZ) is a mixture of acicular ferrite and bainitic ferrite micro- constituents. The microstructure of the base steel is composed of ferrite and pearlite. The anodic dissolution of X80 pipeline steel in simulated Ku'erle soil solution could be enhanced and the SCC sensitivity increased with the increase of CO2 partial pressure. The SCC mechanism of X80 pipeline is a mixing mechanism of hydrogen embrittlement combined with anodic dissolution, and the hydrogen embrittlement plays a leading role. The higher SCC sensitivity of the weld metal was attributed to the metallurgical transformation, local hardening and residual stress. 展开更多
关键词 X80 steel Weld metal co2 partial pressure SCC
原文传递
Response of sea-surface partial pressure of CO_(2)to ENSO events over the Taiwan Strait
2
作者 Keyu Hu Qiong Wu +4 位作者 Tianqi Xiong Bo Li Peng Bai Zhenxin Ruan Chengcheng Yu 《Acta Oceanologica Sinica》 2025年第6期42-53,共12页
El Niño-Southern Oscillation(ENSO)affects the changes in ocean physical elements in Taiwan Strait(TWS)primarily by regulating the strength of the East Asian Winter Monsoon(EAWM)and the intrusion of the Kuroshio.A... El Niño-Southern Oscillation(ENSO)affects the changes in ocean physical elements in Taiwan Strait(TWS)primarily by regulating the strength of the East Asian Winter Monsoon(EAWM)and the intrusion of the Kuroshio.Additionally,the fluctuating impact between nutrient-poor seawater with high dissolved inorganic carbon(DIC)that infiltrates owing to the Kuroshio during El Niño phases and nutrient-rich seawater with low DIC from the South China Sea(SCS)carried by the EAWM during La Niña phases determines the nutrient content in TWS,thereby sculpting appropriate or unsuitable biochemical environment.In this study,based on high-resolution sea-surface partial pressure of carbon dioxide(pCO_(2))data,we investigate the relationship between pCO_(2)level of TWS and ENSO events in winter.The physical mechanisms affecting the anomalous distribution of pCO_(2)level during ENSO are also explored.Stepwise regression was employed to identify the optimal influencing factors for modeling pCO_(2).Results indicate a significant positive correlation between Niño3.4 index and pCO_(2),which is significantly influenced by factors such as sea-surface temperature(SST),chlorophyll-a(Chl a),and DIC.These are related to the anomalously strong Kuroshio intrusion and weaker EAWM during El Niño years.It brings a large amount of high SST water with low nutrient concentration and high DIC,which is detrimental to CO_(2)dissolution and phytoplankton growth over the TWS,leading to an increase in pCO_(2).Conversely,pCO_(2)level is significantly low under the influence of SCS seawater during La Niña years.Based on the characterization of the pCO_(2)level response to ENSO,the carbon balance at TWS can be explored. 展开更多
关键词 sea-surface partial pressure of CO_(2) El Niño-Southern Oscillation Taiwan Strait East Asian Winter Monsoon KUROSHIO
在线阅读 下载PDF
Effect of sliding-cup along governor vessel on tcpO_2 and tapCO_2 in Mìngmén(命门 GV 4) point of sub-healthy humans: observation on different cupping pressure 被引量:1
3
作者 赵义静 陈泽林 +1 位作者 周丹 郭义 《World Journal of Acupuncture-Moxibustion》 CSCD 2015年第3期11-16,共6页
Objective To explore the effects of sliding-cup with different parameters on energy metabolism in the body by observing the effect of sliding-cup along the governor vessel on transcutaneous partial pressures of oxygen... Objective To explore the effects of sliding-cup with different parameters on energy metabolism in the body by observing the effect of sliding-cup along the governor vessel on transcutaneous partial pressures of oxygen and carbon dioxide in Mìngmén(命门 GV 4) in sub-healthy people. Methods A total of 10 sub-healthy adults at rest were observed and sliding-cup along the governor vessel were conducted with three different parameters, jar-pressure of –0.01~ –0.02 MPa with sliding-cup for 5 min, jar-pressure of –0.02~ –0.03 MPa with sliding-cup for 5 min and jar-pressure of –0.02~ –0.03 MPa with slidingcup for 3 min. Peri Flux System5000 PF5040 module was employed to monitor the changes of transcutaneous partial pressures of oxygen(tcp O2) and carbon dioxide(tcp CO2) in GV 4 at 0 min, 5 min, 10 min, 15 min, 20 min, 25 min and 30 min after sliding-cup with above different interventions in sub-healthy subjects. Results After sliding-cup, tcp O2 increased at first and then decreased over time; there was no difference in tcp O2 after sliding-cupping with different parameters(all P0.05). After sliding-cup, tcp CO2 decreased; there was no difference in tcp CO2 after sliding-cup with different parameters(all P0.05). Conclusion Sliding-cup has a sustained effect on the body and can speed up the energy metabolism in the body. 展开更多
关键词 governor vessel sliding-cup Mingmen(命门GV 4) transcutaneous partial pressure of oxygen(tcpO_2) transcutaneous partial pressure of carbon dioxide(tcpCO_2)
原文传递
Effect of Oxygen Partial Pressure on Phase Equilibria and Liquidus in CaO-Al_2O_3-FeO_x System 被引量:1
4
作者 WANG Nan HUANG Wei-jun CHEN Shuai-chao CHEN Min 《Journal of Iron and Steel Research International》 SCIE EI CAS CSCD 2012年第11期8-12,共5页
A high temperature equilibration experiment was carried out to investigate the effect of oxygen partial pres- sure on the phase equilibria and liquidus in CaO-Al2O3- FeOx system with the intermediate oxygen partial pr... A high temperature equilibration experiment was carried out to investigate the effect of oxygen partial pres- sure on the phase equilibria and liquidus in CaO-Al2O3- FeOx system with the intermediate oxygen partial pressures of 10.13 Pa and 1.01 × 10^-3 Pa. The equilibrated phases and their compositions of the quenched samples were analyzed by using SEM/EPMA (Scanning Electron Microscope/Electron Probe Micro Analysis) and XRD (X Ray Diffraction). The phase equilibrium results include two cases, the two phase coexistence and the three-phase coexistence in the high Al2O3 region with oxygen partial pressure of either 10.13 Pa or 1.01 × 10^-3 Pa. Effects of oxygen partial pressure and temperature on the liquidus along the primary phase fields of CaO · Al2O3 and CaO · 2Al2O3 were nota hle. With the decrease of oxygen partial pressure, the liquid area expands and the liquidus of CaO · Al2O3 and CaO · 2Al2O3 primary fields moves to the Al2O3-FeOx region. On the other hand, the liquid area of CaO Al2O3-FeOx sys tem extends extremely to the high Al2O3 region with the temperature increasing from 1 400 to 1 500℃, especially at lower oxygen partial pressure. The present experiment results are in good agreement with the calculated ones by FactSage. 展开更多
关键词 oxygen partial pressure LIQUIDUS phase equilibrium CaO-Al2O3 FeOx system
原文传递
Effect of N_(2) partial pressure on comprehensive properties of antibacterial TiN/Cu nanocomposite coating 被引量:1
5
作者 Hui Liu Yanhui Zhao +10 位作者 Chuanshi Sui Yi Li Muhammad Ali Siddiqui Susu Li Tong Li Shuyuan Zhang Hai Wang Tao Jin Ling Ren Ke Yang Ning Zhang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第1期131-143,共13页
Foreign body reactions to the wear debris and corrosion products from the implants,and bacterial infections are the main factors leading to the implant failures.In order to resolve these problems,the antibacterial TiN... Foreign body reactions to the wear debris and corrosion products from the implants,and bacterial infections are the main factors leading to the implant failures.In order to resolve these problems,the antibacterial TiN/Cu nanocomposite coatings with various N_(2) partial pressures were deposited on 304 stainless steels(SS)using an arc ion plating(AIP)system,named TiN/Cu-x(x=0.5,1.0,1.5 Pa).The results of X-ray diffraction analysis,energy-dispersive X-ray spectroscopy,and scanning electron microscopy showed that the N_(2) partial pressures determined the Cu contents,surface defects,and crystallite sizes of TiN/Cu nanocomposite coatings,which further influenced the comprehensive abilities.And the hardness and wear resistances of TiN/Cu coatings were enhanced with increase of the crystallite sizes.Under the co-actions of surface defects,crystallite sizes,and Cu content,TiN/Cu-1.0 and TiN/Cu-1.5 coatings possessed excellent corrosion resistance.Besides,the biological tests proved that all the TiN/Cu coatings showed no cytotoxicity with strong antibacterial ability.Among them,TiN/Cu-1.5 coating significantly promoted the cell proliferation,which is expected to be a novel antibacterial,corrosion-resistant,and wear-resistant coating on the surfaces of medical implants. 展开更多
关键词 N_(2)partial pressure TiN/Cu coating wear resistance corrosion behavior antibacterial ability CYTOCOMpATIBILITY
在线阅读 下载PDF
夏季东海西部表层海水中的pCO_2及海-气界面通量 被引量:34
6
作者 谭燕 张龙军 +1 位作者 王凡 胡敦欣 《海洋与湖沼》 CAS CSCD 北大核心 2004年第3期239-245,共7页
根据 2 0 0 1年夏季长江口及东海西部海域表层海水pCO2 的实测数据 ,结合水文、化学和生物等要素的同步观测资料 ,对该海域pCO2 分布和变化的重要影响因素进行了探讨。结果表明 ,长江冲淡水是造成东海西部海域表层海水pCO2 分布不均匀... 根据 2 0 0 1年夏季长江口及东海西部海域表层海水pCO2 的实测数据 ,结合水文、化学和生物等要素的同步观测资料 ,对该海域pCO2 分布和变化的重要影响因素进行了探讨。结果表明 ,长江冲淡水是造成东海西部海域表层海水pCO2 分布不均匀的主要原因。利用Wan ninkhof( 1 992 )提出的通量模式计算 ,长江口口门附近海域和浙江近岸海域为CO2 的源区 ,1 2 3°E以东的调查海域表现为大气CO2 的汇 ,尤其是以 1 2 3°E ,32°N为中心 ,存在着一个极强的大气CO2 汇区。就整个东海西部海域而言 ,夏季可从大气净吸收 1 5 3× 1 0 4 tC。 展开更多
关键词 东海 二氧化碳分压(pco2) 碳通量
在线阅读 下载PDF
Thermokinetic and conductivity analyzes of the high CO2 chemisorption on Li5AlO4 and alkaline carbonate impregnated Li5AlO4 samples:Effects produced by the use of CO2 partial pressures and oxygen addition
7
作者 Pedro Sánchez-Camacho J.Francisco Gómez-García Heriberto Pfeiffer 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2017年第5期919-926,共8页
The effect of COpartial pressure was evaluated during the COchemisorption in penta lithium aluminate(LiAlO), using different COand Opartial pressures in the presence or absence of alkaline carbonates. Results showed... The effect of COpartial pressure was evaluated during the COchemisorption in penta lithium aluminate(LiAlO), using different COand Opartial pressures in the presence or absence of alkaline carbonates. Results showed that using low PO(0.1) did not affect the kinetic and final COchemisorption process. Moreover, small additions of oxygen(PO= 0.05) into the mixture flue gas, seemed to increase the COchemisorption. Additionally, the presence of alkaline carbonates modified the COcapture temperature range. COchemisorption kinetic parameters were determined assuming a double exponential model where direct COchemisorption and COchemisorption controlled by diffusion processes are considered.Finally, ionic diffusion was analyzed by ionic conduction analysis, where all the gravimetric and ionic measurements were in good agreement showing different diffusion processes depending on temperature.Finally, the oxygen and alkaline carbonate additions have positive effects during the COchemisorption process in LiAlO, and a possible reaction mechanism is presented. 展开更多
关键词 co2 capture Thermogravimetric analysis partial pressure Ionic conduction
在线阅读 下载PDF
Effect of N_2-Gas Partial Pressure on the Structure and Properties of Copper Nitride Films by DC Reactive Magnetron Sputtering
8
作者 刘祖黎 李兴鳌 +3 位作者 左安友 袁作彬 杨建平 姚凯伦 《Plasma Science and Technology》 SCIE EI CAS CSCD 2007年第2期147-151,共5页
Copper nitride thin films were deposited on glass substrates by reactive direct current (DC) magnetron sputtering at various N2-gas partial pressures and room temperature. Xray diffraction measurements showed that t... Copper nitride thin films were deposited on glass substrates by reactive direct current (DC) magnetron sputtering at various N2-gas partial pressures and room temperature. Xray diffraction measurements showed that the films were composed of Cu3N crystallites and exhibited a preferential orientation of the [111] direction at a low nitrogen gas (N2) partial pressure. The film growth preferred the [111] and the [100] direction at a high N2 partial pressure. Such preferential film growth is interpreted as being due to the variation in the Copper (Cu) nitrification rate with the N2 pressure. The N2 partial pressure affects not only the crystal structure of the film but also the deposition rate and the resistivity of the Cu3N film. In our experiment, the deposition rate of Cu3N films was 18 nm/min to 30 nm/min and increased with the N2 partial pressure. The resistivity of the Cu3N films increased sharply with the increasing N2 partial pressure. At a low N2 partial pressure, the Cu3N films showed a metallic conduction mechanism through the Cu path, and at a high N2 partial pressure, the conductivity of the Cu3N films showed a semiconductor conduction mechanism. 展开更多
关键词 Cu3N film DC magnetron sputtering N2-gas partial pressure RESISTIVITY
在线阅读 下载PDF
FiO_2及PEEP对腹腔镜行下宫颈癌根治术全麻患者P_(a-ET)CO_2的影响 被引量:1
9
作者 王瑚 曹奕 华晓君 《实用癌症杂志》 2014年第1期62-65,共4页
目的评价不同吸入氧浓度(FiO2)和呼气末正压(PEEP)对腹腔镜下行宫颈癌根治术全麻患者动脉血-呼气末二氧化碳分压差[P(a-ET)CO2]的影响。方法将108例腹腔镜下行根治术的宫颈癌患者分为4组,每组27例:第1组给予FiO2(100%的纯氧)和0 mmHg的P... 目的评价不同吸入氧浓度(FiO2)和呼气末正压(PEEP)对腹腔镜下行宫颈癌根治术全麻患者动脉血-呼气末二氧化碳分压差[P(a-ET)CO2]的影响。方法将108例腹腔镜下行根治术的宫颈癌患者分为4组,每组27例:第1组给予FiO2(100%的纯氧)和0 mmHg的PEEP;第2组给予FiO2(100%的纯氧)和7.0 mmHg的PEEP;第3组给予FiO2(50%的纯氧)和0 mmHg的PEEP;第4组给予FiO2(50%的纯氧)和7.0 mmHg的PEEP,均在即时(T1)和30 min(T2)和60 min(T3)三个时间点时分别检测动脉血二氧化碳分压(PaCO2),呼气末二氧化碳分压(P ET CO2),P(a-ET)CO2。结果不同时间点组间比较:T1时1、2、3、4组间PaCO2、和P(a-ET)CO2相互比较差异无统计学意义(P>0.05);T2和T3时,1组与2组比较、3组与4组比较、1组与3组比较、2组与4组比较PaCO2和P(a-ET)CO2差异均有统计学意义(P<0.05)。结论 FiO2浓度较高时,同时一定要相应提高PEEP,则可以有效降低P(a-ET)CO2;PEEP较低时,同时一定要降低FiO2浓度,这样可以有效降低P(a-ET)CO2。 展开更多
关键词 收入氧浓度 呼气末正压 动脉血二氧化碳分压差 气末二氧化碳分压
暂未订购
Evaluation of the net CO_2 uptake in the Canada Basin in the summer of 2008 被引量:2
10
作者 SUN Heng GAO Zhongyong +2 位作者 LU Peng XIU Peng CHEN Liqi 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2017年第8期94-100,共7页
The third Chinese National Arctic Research Expedition (CHINARE) was conducted in the summer of 2008. During the survey, the surface seawater partial pressure of CO2 (pCO2) was measured, and sea water samples were ... The third Chinese National Arctic Research Expedition (CHINARE) was conducted in the summer of 2008. During the survey, the surface seawater partial pressure of CO2 (pCO2) was measured, and sea water samples were collected for CO2 measurement in the Canada Basin. The distribution of pCO2 in the Canada Basin was determined, the influencing factors were addressed, and the air-sea CO2 flux in the Canada Basin was evaluated. The Canada Basin was divided into three regions: the ice-free zone (south of 77°N), the partially ice-covered zone (77°-80°N), and the heavily ice-covered zone (north of 80°N). In the ice-free zone, pCO2 was high (320 to 368 patm, 1 patm=0.101 325 Pa), primarily due to rapid equilibration with atmospheric CO2 over a short time. In the partially ice-covered zone, the surface pCOs was relatively low (250 to 270 patm) due to ice-edge blooms and icemelt water dilution. In the heavily ice-covered zone, the seawater pCO2 varied between 270 and 300 laatm due to biological COs removal, the transportation of low pCOs water northward, and heavy ice cover. The surface seawater pCO2 during the survey was undersaturated with respect to the atmosphere in the Canada Basin, and it was a net sink for atmospheric CO2. The summertime net CO2 uptake of the ice-free zone, the partially ice-covered zone and the heavily ice-covered zone was (4.14±1.08), (1.79±0.19), and (0.57±0.03) Tg/a (calculated by carbon, 1 Tg=10^12 g), respectively. Overall, the net COs sink of the Canada Basin in the summer of 2008 was (6.5+1.3) Tg/a, which accounted for 4%-10% of the Arctic Ocean COs sink. 展开更多
关键词 Canada Basin net co2 uptake partial pressure of co2
在线阅读 下载PDF
Distributions and Relationships of CO_2,O_2,and Dimethylsulfide in the Changjiang(Yangtze) Estuary and Its Adjacent Waters in Summer
11
作者 WU Xi TAN Tingting +3 位作者 LIU Chunying LI Tie LIU Xiaoshou YANG Guipeng 《Journal of Ocean University of China》 SCIE CAS CSCD 2018年第2期320-334,共15页
The distributions and relationships of O_2, CO_2, and dimethylsulfide (DMS) in the Changjiang (Yangtze) Estuary and its adjacent waters were investigated in June 2014. In surface water, mean O_2 saturation level, part... The distributions and relationships of O_2, CO_2, and dimethylsulfide (DMS) in the Changjiang (Yangtze) Estuary and its adjacent waters were investigated in June 2014. In surface water, mean O_2 saturation level, partial pressure of CO_2 (pCO_2), and DMS concentrations (and ranges) were 110% (89%–167%), 374μatm (91–640 μatm), and 8.53 nmol L^(-1) (1.10–27.50 nmol L^(-1)), respectively. The sea-to-air fluxes (and ranges) of DMS and CO_2 were 8.24 μmol m^(-2)d^(-1) (0.26–62.77 μmol m^(-2)d^(-1)), and -4.7 mmol m^(-2)d^(-1) (-110.8-31.7 mmol m^(-2)d^(-1)), respectively. Dissolved O_2 was oversaturated, DMS concentrations were relatively high, and this region served as a sink of atmospheric CO_2. The pCO_2 was significantly and negatively correlated with the O_2 saturation level, while the DMS concentration showed different positive relationships with the O_2 saturation level in different water masses. In vertical profiles, a hypoxic zone existed below 20 m at a longitude of 123?E. The stratification of temperature and salinity caused by the Taiwan Warm Current suppressed seawater exchange between upper and lower layers, resulting in the formation of a hypoxic zone. Oxidative de-composition of organic detritus carried by the Changjiang River Diluted Water (CRDW) consumed abundant O_2 and produced additional CO_2. The DMS concentrations decreased because of low phytoplankton biomass in the hypoxic zone. Strong correlations ap-peared between the O_2 saturation level, pCO_2 and DMS concentrations in vertical profiles. Our results strongly suggested that CRDW played an important role in the distributions and relationships of O_2, CO_2, and DMS. 展开更多
关键词 O2 partial pressure of co2(pco2) dimethylsulfide(DMS) CHANGJIANG ESTUARY distribution relationship
在线阅读 下载PDF
H_2S分压对油管钢CO_2/H_2S腐蚀的影响 被引量:46
12
作者 张清 李全安 +1 位作者 文九巴 白真权 《腐蚀科学与防护技术》 CAS CSCD 北大核心 2004年第6期395-397,共3页
采用高温高压釜 ,辅以失重法和扫描电镜 ,对不同H2 S分压下 (1 4kPa,2 0kPa ,6 0kPa ,12 0kPa)油管钢N80、P110的CO2 /H2 S腐蚀进行了研究 .结果表明 ,在试验H2 S分压范围内 ,随着H2 S分压的升高 ,两种钢的腐蚀速率先增后降 ,且都在H2 ... 采用高温高压釜 ,辅以失重法和扫描电镜 ,对不同H2 S分压下 (1 4kPa,2 0kPa ,6 0kPa ,12 0kPa)油管钢N80、P110的CO2 /H2 S腐蚀进行了研究 .结果表明 ,在试验H2 S分压范围内 ,随着H2 S分压的升高 ,两种钢的腐蚀速率先增后降 ,且都在H2 S分压为 2 0kPa时取得最大值 . 展开更多
关键词 油管钢 co2/H2S腐蚀 失重法 腐蚀速率 高温高压 扫描电镜 分压
在线阅读 下载PDF
Direct Measurement of CO_2 Retention in Arable Soils with pH Above 6.5 During Barometric Process Separation Incubation
13
作者 Hannah CONRADS Joachim INGWERSEN +1 位作者 JU Xiaotang Thilo STRECK 《Pedosphere》 SCIE CAS CSCD 2018年第5期726-738,共13页
The barometric process separation(BaPS)technique is a well-established incubation method to simultaneously measure gross nitrification and respiration rates in soil.Its application,however,is still critical in soils w... The barometric process separation(BaPS)technique is a well-established incubation method to simultaneously measure gross nitrification and respiration rates in soil.Its application,however,is still critical in soils with pH above 6.5.Here,a substantial part of microbial CO_2 production is retained in soil solution(CO_2,aq)due to shifts in the carbonate equilibrium.This may lead to substantial errors in gas balance calculation.Yet,utilization of the BaPS technique is only reliable if the critical term is adequately quantified.We present an easy,inexpensive,and direct method,the sterilization-CO_2-injection(SCI)method,to measure CO_2 retention during soil incubation.Sterilized soil was incubated in the BaPS system,and defined volumes of CO_2 were injected to stepwise increase CO_2partial pressure(p CO_2)inside the chamber and to analyse the physicochemical equilibration process.Five exemplary agricultural soils from Northeast China and Southwest Germany were used for method establishment,presenting pH values between 4.4 and 7.6 and carbonate contents between 0% and 3.9%.We observed that in soils with pH>6.5,70%–90% of the injected CO_2 was taken up by the soil until the equilibrium inside the chamber was re-established.As expected,in soils with low pH(<6.5),measured CO_2 retention was low.CO_2 retention patterns were sensitive to incubation temperature with tri-fold dissolution capacity at 5~?C compared to 25?C,but insensitive to variations in soil water content.The resulting soil-specific relationship between p CO_2 and CO_2,aq concentration allowed the quantification of CO_2,aq concentration as a function of headspace p CO_2. 展开更多
关键词 carbonate equilibrium co2 dissolution capacity CO_2 partial pressure microbial co2 production soil pH sterilization-co2-injection method volume of headspace air volume of soil solution
原文传递
Clinical Study of P_(ET)CO_2 in One-lung Ventilation
14
作者 张传汉 马自成 金士翱 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 1996年第3期179-182,共4页
Fourty-eight patients (ASA physical status Ⅰ - Ⅱ) undergoing selected thoracotomy and pulmonectomy were studied. They were divided into two groups according to different respiratory modes, two-lung ventilation (TLV)... Fourty-eight patients (ASA physical status Ⅰ - Ⅱ) undergoing selected thoracotomy and pulmonectomy were studied. They were divided into two groups according to different respiratory modes, two-lung ventilation (TLV) and onelung ventilation (OLV) or TLV and OLV with a Bain cyclic system for CPAP on the side of operated lung. PETCO2 and PaCO2 were measured after 30 min TLV,30 min and 60 min OLV, and repeated TLV (R-TLV) 30 min after pulmonectomy, to evaluate the difference between PETCO2 and PaCO2 in OLV and to observethe effect of abating hypoxemia and discharge of CO2 in OLV with Bain system.Our results showed that the PaCO2 and PETCO2 in different test groups were normal though the measured values in OLV were slightly higher than that in TLV (P<0. 05) , and then they were recovered after R-TLV (P>0. 05). There was nosignificant difference between group 1. and 2. in OLV (P>0. 05). There was aclose correlation between PETCO2 and PaCO2 (P<0. 05). The differences of the calculated P(a-ET)CO2 and radio of PETCO2/PaCO2 in different ventilation modes were not significant. Hypoxemia in OLV was corrected by Bain system, but the discharge of CO2 was not affected. The results showed that measurement of PET CO2 as a non-invasive procedure can be commonly used to monitor OLV. 展开更多
关键词 CO_2 partial pressure one-lung ventilation non-invasive monitoring
暂未订购
倍增CO_2分压对水稻和矶子草冠层光合潜力的影响 被引量:9
15
作者 孙谷畴 赵平 +1 位作者 曾小平 彭少麟 《生态学杂志》 CAS CSCD 北大核心 2003年第4期1-5,共5页
倍增CO2 分压增高水稻的光饱和光合速率、表观量子产率和光能转换效率 ,而在倍增CO2 分压下矶子草的相关光合参数降低 ,既水稻对高CO2 分压表现为正响应 ,而矶子草在高CO2 下光合作用下调。在倍增CO2 分压下 ,水稻的Rubisco羧化速率和... 倍增CO2 分压增高水稻的光饱和光合速率、表观量子产率和光能转换效率 ,而在倍增CO2 分压下矶子草的相关光合参数降低 ,既水稻对高CO2 分压表现为正响应 ,而矶子草在高CO2 下光合作用下调。在倍增CO2 分压下 ,水稻的Rubisco羧化速率和氧化速率均见增高 ,而矶子草在高CO2 分压下 ,Rubisco羧化速率降低 ,而氧化速率略见增高。倍增CO2 分压并不明显改变水稻的不包括光呼吸的CO2 补偿点Γ ,但矶子草Γ 略见增高。在高CO2 分压下可能改变矶子草Rubisco生化特性。倍增CO2 分压降低两种供试植物的光下呼吸速率。水稻在倍增CO2 分压下其Rubisco最大羧化速率 (Vcmax)和最大电子传递速率 (Jmax)分别增高 9 3%和 2 0 7% ,而矶子草在高CO2 分压下则分别降低 5 7%和 3%。在倍增CO2 分压下水稻的净光合量增高约 5 % ,而矶子草则降低 13% ,植物种的不同特性可能影响植物在倍增CO2 下的碳积累。随着全球气候变化和大气CO2 分压增高 ,将有利于发挥水稻高光合产率的优势 ,由于矶子草在高CO2 分压下碳积累减少 ,从而可能限制其生长。大气CO2 展开更多
关键词 倍增co2分压 水稻 矶子草 冠层光合潜力
在线阅读 下载PDF
CO_2分压对油管钢腐蚀产物膜的影响 被引量:8
16
作者 张清 李全安 +2 位作者 文九巴 林冠发 白真权 《石油机械》 北大核心 2004年第4期13-14,36,共3页
利用静态高压釜对 3种油管钢N80、P1 1 0和J5 5进行了CO2 腐蚀试验 ,通过扫描电镜(SEM)对比分析了腐蚀产物膜的厚度和表面晶粒尺寸的变化规律。结果表明 ,在试验条件下 ,3种钢的腐蚀产物膜均为双层结构 ;膜厚随CO2 分压变化情况比较相... 利用静态高压釜对 3种油管钢N80、P1 1 0和J5 5进行了CO2 腐蚀试验 ,通过扫描电镜(SEM)对比分析了腐蚀产物膜的厚度和表面晶粒尺寸的变化规律。结果表明 ,在试验条件下 ,3种钢的腐蚀产物膜均为双层结构 ;膜厚随CO2 分压变化情况比较相近 ,在CO2 分压为 6 90MPa时均达到最大 ,在超临界压力以上急剧减小 ;表面晶粒尺寸随CO2 分压变化出现 2峰 1谷 ,在超临界压力以上急剧减小。 展开更多
关键词 油管 腐蚀作用 co2 超临界压力 石油 天然气
在线阅读 下载PDF
血清AQP4、HMGB1、FGL2水平联合颅内压和脑组织氧分压监测在创伤性脑损伤患者预后中的价值
17
作者 王文 郑从波 +3 位作者 胡芳宝 窦红杰 凌林 王德强 《疑难病杂志》 2025年第1期29-34,共6页
目的探讨血清通道蛋白4(AQP4)、高迁移率族蛋白B1(HMGB1)、纤维蛋白原样蛋白2(FGL2)水平联合颅内压和脑组织氧分压(PbtO_(2))监测在创伤性脑损伤(TBI)患者预后中的价值。方法选取2022年5月—2024年5月上海交通大学附属第六人民医院南院... 目的探讨血清通道蛋白4(AQP4)、高迁移率族蛋白B1(HMGB1)、纤维蛋白原样蛋白2(FGL2)水平联合颅内压和脑组织氧分压(PbtO_(2))监测在创伤性脑损伤(TBI)患者预后中的价值。方法选取2022年5月—2024年5月上海交通大学附属第六人民医院南院/上海市奉贤区中心医院重症医学科诊治的TBI患者128例为研究对象,根据患者治疗后随访3个月预后情况,将其分为预后不良组(n=38)、预后良好组(n=90)。采用ELISA法检测血清AQP4、HMGB1、FGL2水平;Spearman法分析TBI不同预后患者颅内压、PbtO_(2)、血清AQP4、HMGB1、FGL2与格拉斯哥昏迷量表(GCS)评分的相关性;运用ROC曲线分析颅内压、PbtO_(2)联合血清AQP4、HMGB1、FGL2对TBI患者预后的预测价值。结果预后不良组患者颅内压高于预后良好组,GCS评分、PbtO_(2)值显著低于预后良好组(t/P=7.491/<0.001、9.882/<0.001、7.215/<0.001)。预后不良组血清AQP4、HMGB1、FGL2水平明显高于预后良好组(t/P=7.106/<0.001、7.642/<0.001、7.383/<0.001);患者PbtO_(2)与GCS评分呈显著正相关(r/P=0.523/<0.001),而颅内压、血清AQP4、HMGB1、FGL2与GCS评分呈显著负相关(r/P=-0.515/<0.001、-0.492/<0.001、-0.617/<0.001、-0.569/<0.001);血清AQP4、HMGB1、FGL2、颅内压、PbtO_(2)及五者联合预测TBI患者预后的曲线下面积(AUC)分别为0.882、0.876、0.817、0.825、0.756、0.969,五者联合优于各自单独预测TBI患者预后的价值(Z/P=2.803/0.005、2.769/0.006、3.543/<0.001、3.269/0.001、3.956/<0.001)。结论TBI患者颅内压、血清AQP4、HMGB1、FGL2水平显著升高,PbtO_(2)显著降低,与患者预后有着紧密联系,联合检测对TBI患者预后有更高的预测价值。 展开更多
关键词 创伤性脑损伤 脑组织氧分压 通道蛋白4 高迁移率族蛋白B1 纤维蛋白原样蛋白2 预后
暂未订购
电针在术中改善CO_2气腹应激损伤的临床研究 被引量:1
18
作者 张翮 王兰 +5 位作者 张敏 陈彤宇 吴晓珲 陈静 鲍丹 沈卫东 《针灸临床杂志》 2013年第8期30-35,共6页
目的:通过检测术中胃粘膜CO2分压、胃粘膜ph值、白介素-2和表皮生长因子的变化,观察电针对术中CO2气腹应激损伤的改善效果。方法:收治妇科腹腔镜手术病人60例,行随机、单盲、对照的临床试验。病人分为两组,I组30例,施以常规全身麻醉;Ⅱ... 目的:通过检测术中胃粘膜CO2分压、胃粘膜ph值、白介素-2和表皮生长因子的变化,观察电针对术中CO2气腹应激损伤的改善效果。方法:收治妇科腹腔镜手术病人60例,行随机、单盲、对照的临床试验。病人分为两组,I组30例,施以常规全身麻醉;Ⅱ组30例,在常规全身麻醉基础上,复合穴位电针,从进入手术室开始一直持续到手术结束。在不同时间点获取反映CO2气腹应激损伤的相关数据,以备评价所用。结果:胃粘膜CO2分压、胃粘膜ph值、白介素-2和表皮生长因子的组间、组内数值变化均存在显著差异(P<0.01)。结论:电针应用在全麻妇科腹腔镜手术中,能够保证胃粘膜的血氧供应,防止胃粘膜局部缺血或低灌注,维持胃黏膜屏障的生理功能,达到减轻CO2气腹对机体应激损伤的临床效果。 展开更多
关键词 电针 co2气腹 胃粘膜co2分压 胃粘膜pH值 白介素-2 表皮生长因子
暂未订购
载人航天器组合体CO_2分压控制策略分析 被引量:1
19
作者 靳健 陈伯翰 《系统工程与电子技术》 EI CSCD 北大核心 2018年第6期1351-1357,共7页
随着载人航天技术的发展,载人航天器由单舱段构型逐渐发展成为多舱段组合体构型,其中一个或若干个舱段在舱间通风的支持下对组合体密封舱内空气环境进行集中控制。利用多学科建模工具Ecosimpro建立了载人航天器组合体CO_2分压控制计算模... 随着载人航天技术的发展,载人航天器由单舱段构型逐渐发展成为多舱段组合体构型,其中一个或若干个舱段在舱间通风的支持下对组合体密封舱内空气环境进行集中控制。利用多学科建模工具Ecosimpro建立了载人航天器组合体CO_2分压控制计算模型,对载人航天器组合体组建过程中,各舱CO_2分压水平进行了分析。当舱段数达到3个以上,将会出现非主控舱CO_2分压超标现象。针对CO_2分压超标现象,提出了3种控制策略:提高全部舱间通风量、更改CO_2控制系统位置、提高部分舱间通风量+更改CO_2控制系统位置,并对3种控制策略的效果进行了仿真分析。结果表明,更改CO_2控制系统位置并提高部分舱间通风量是最有效的载人航天器组合体CO_2分压控制策略。 展开更多
关键词 载人航天器组合体 co2分压 舱间通风 仿真分析 控制策略
在线阅读 下载PDF
春季典型亚热带珊瑚礁海域海水pCO_(2)的变化特征及其调控机制
20
作者 杨波 张卓 +5 位作者 周进 林子燚 谢子强 郑惠娜 廖宝林 肖宝华 《海洋学研究》 北大核心 2025年第1期90-106,共17页
由于存在极高的初级生产和高效的碳代谢速率,珊瑚礁海域二氧化碳(CO_(2))的汇源属性仍存有争议。为了明晰我国亚热带珊瑚礁海域CO_(2)的源、汇特征及驱动因素,基于2023年5月的海上调查结果并结合室内培养实验数据,本文探究了春季大澳湾... 由于存在极高的初级生产和高效的碳代谢速率,珊瑚礁海域二氧化碳(CO_(2))的汇源属性仍存有争议。为了明晰我国亚热带珊瑚礁海域CO_(2)的源、汇特征及驱动因素,基于2023年5月的海上调查结果并结合室内培养实验数据,本文探究了春季大澳湾(珊瑚礁海域)海水CO_(2)分压(pCO_(2))的分布特征及主要控制机制。结果表明:春季大澳湾海水pCO_(2)的范围为412.9~555.7μatm,主要表现为大气CO_(2)的源,平均释放通量为0.53±0.90 mmol·m^(-2)·d^(-1)。调查期间,pCO_(2)整体呈现近岸高于远岸的分布特征,这主要受到生物活动(净呼吸)和陆源淡水输入的共同控制。此外,海水pCO_(2)的日周期变化显著,其差值最高可达168μatm。生物活动(光合和呼吸作用)的昼夜差异是导致pCO_(2)日变化的主要因素,在礁区和非礁区对pCO_(2)日变化的贡献分别为89.4%和66.4%。物理过程(温度和潮汐作用)对pCO_(2)昼夜变化的影响较小,其中温度变化在礁区和非礁区的贡献分别为12.7%和21.5%,其作用远低于生物过程。此外,近岸珊瑚的代谢过程可能会显著提升大澳湾局部(礁区)的pCO_(2),增强海域的CO_(2)源属性。 展开更多
关键词 珊瑚礁 pCO_(2) 海-气CO_(2)通量 源汇特征 大澳湾 钙化作用 呼吸作用 光合作用
在线阅读 下载PDF
上一页 1 2 7 下一页 到第
使用帮助 返回顶部