期刊文献+
共找到7篇文章
< 1 >
每页显示 20 50 100
Influence of the position relationship between gas–liquid interface and laser focus on plasma evolution characteristics in jet LIBS technology
1
作者 薛媛媛 隋明达 +7 位作者 刘润泽 王一平 郭金家 田野 李佳珉 刘眉洁 钟石磊 薛塨译 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第8期103-112,共10页
In order to understand the characteristics of breakdown process,plasma evolution and spectral emission in liquid jets laser-induced breakdown spectroscopy methods under the influence of the position variation between ... In order to understand the characteristics of breakdown process,plasma evolution and spectral emission in liquid jets laser-induced breakdown spectroscopy methods under the influence of the position variation between laser focus and gas–liquid interface,this work takes the plasma generated by laser-induced liquid jets as the object of study and discusses the changes in the spatial and temporal evolution characteristics and spectral radiation of the plasma when the position parameters between the laser focal point and the gas–liquid interface are different.The initial breakdown position is always between the front interface and the focus when the laser focus moves along the vertical direction of the interface,forming a phenomenon like’interface effect’.The relationship between laser pulse energy and breakdown probability exhibits a law similar to a‘hysteresis curve’in the study of breakdown threshold.In this work,plasma with smaller size,rounder shape,stronger radiation,higher temperature,and higher density can be produced when the focus position is in the liquid column 0.2 mm away from the front interface.Simultaneously,the spectral signal intensity and signal-to-back ratio of the characteristic peaks of target elements in water reach maximum values,and the spectral signal becomes more stable(relative standard deviation value reaches 2%).The Ca element’s ion radiation at 393.366 nm and atomic radiation at 422.673 nm are studied using narrow-band filtering imaging and time-space resolution spectroscopy.The findings demonstrate that the laws of ion and atomic radiation are not perfectly consistent in space and time. 展开更多
关键词 laser spectroscopy plasma-material interactions boundary layer effects particle and heat loss energy balance field structure plasma temperature and density
下载PDF
In-situ detection equipment for radon-in-water:unattended operation and monthly investigations
2
作者 Chunqian Li Meng Li +11 位作者 Guangquan Chen Huaming Yu Chenglun Zhang Wen Liu jinjia guo Shibin Zhao Lijun Song Xiliang Cui Ying Chai Lu Cao Diansheng Ji Bochao Xu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第8期178-184,共7页
Radon is recognized as a powerful tracer of certain geophysical processes in marine and aquatic environments.In the past few decades,the instruments and methods for measuring radon concentration in water have been dev... Radon is recognized as a powerful tracer of certain geophysical processes in marine and aquatic environments.In the past few decades,the instruments and methods for measuring radon concentration in water have been developed to some extent but still lack underwater in-situ measurements.Here we present an in-situ detection equipment for radon-in-water(pulsed ionization chamber(PIC)-radon)to measure dissolved radon in ocean and groundwater settings.The equipment has been successfully deployed in the Jiaozhou Bay in July 2022 and has achieved 14 d of unattended underwater in-situ observation.Then it was successfully placed in a groundwater monitoring well in the Laizhou Bay in November 2022 and monitored radon activities for over 30 d.The results showed that this instrument had a good indication of submarine groundwater discharge.The PIC-radon detector takes advantage of smaller size,lower power consumption,and is barely influenced by humidity,making it particularly suitable for long-term in-situ measurement,especially in harsh environments with limited human care or deployment spaces. 展开更多
关键词 RADON pulsed ionization chamber(PIC) in-situ measurement membrane GROUNDWATER OCEAN
下载PDF
Measuring^(222)Rn in aquatic environment via Pulsed Ionization Chamber Radon Detector
3
作者 Lijun Song Wen Liu +4 位作者 Shibin Zhao Chunqian Li jinjia guo Natasha Dimova Bochao Xu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第8期185-189,I0001-I0006,共11页
Radon(Rn)is a naturally occurring radioactive inert gas in nature,and^(222)Rn has been routinely used as a powerful tracer in various aquatic environmental research on timescales of hours to days,such as submarine gro... Radon(Rn)is a naturally occurring radioactive inert gas in nature,and^(222)Rn has been routinely used as a powerful tracer in various aquatic environmental research on timescales of hours to days,such as submarine groundwater discharge.Here we developed a new approach to measure^(222)Rn in discrete water samples with a wide range of^(222)Rn concentrations using a Pulsed Ionization Chamber(PIC)Radon Detector.The sensitivity of the new PIC system is evaluated at 6.06 counts per minute for 1 Bq/L when a 500 mL water sample volume is used.A robust logarithmic correlation between sample volumes,ranging from 250 mL to 5000 mL,and system sensitivity obtained in this study strongly suggests that this approach is suitable for measuring radon concentration levels in various natural waters.Compared to the currently available methods for measuring radon in grab samples,the PIC system is cheaper,easier to operate and does not require extra accessories(e.g.,drying tubes etc.)to maintain stable measurements throughout the counting procedure. 展开更多
关键词 ^(222)Rn radon measurement Pulsed Ionization Chamber Radon Detector radon in discrete water samples submarine groundwater discharge
下载PDF
Spectra-assisted laser focusing in quantitative analysis of laser-induced breakdown spectroscopy for copper alloys
4
作者 李守杰 郑荣儿 +5 位作者 出口祥啓 叶旺全 田野 郭金家 李颖 卢渊 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第4期204-209,共6页
Laser-induced breakdown spectroscopy(LIBS)is a capable technique for elementary analysis,while LIBS quantitation is still under development.In quantitation,precise laser focusing plays an important role because it ens... Laser-induced breakdown spectroscopy(LIBS)is a capable technique for elementary analysis,while LIBS quantitation is still under development.In quantitation,precise laser focusing plays an important role because it ensures the distance between the laser and samples.In the present work,we employed spectral intensity as a direct way to assist laser focusing in LIBS quantitation for copper alloys.It is found that both the air emission and the copper line could be used to determine the position of the sample surface by referencing the intensity maximum.Nevertheless,the fine quantitation was only realized at the position where the air emission(e.g.O(I)777.4 nm)reached intensity maximum,and also in this way,a repeatable quantitation was successfully achieved even after 120 days.The results suggested that the LIBS quantitation was highly dependent on the focusing position of the laser,and spectra-assisted focusing could be a simple way to find the identical condition for different samples’detection.In the future,this method might be applicable in field measurements for LIBS analysis of solids. 展开更多
关键词 LIBS laser focusing spectra assistance quantitative analysis copper alloys
下载PDF
Study of pressure effects on ocean in-situ detection using laser-induced breakdown spectroscopy 被引量:3
5
作者 jinjia guo Nan LI +1 位作者 Jiaojian SONG Ronger ZHENG 《Plasma Science and Technology》 SCIE EI CAS CSCD 2019年第3期182-187,共6页
Laser-induced breakdown spectroscopy(LIBS) has attracted extensive attention as a new technique for in-situ marine application. In this work, the influence of deep-sea high pressure environment on LIBS signals was inv... Laser-induced breakdown spectroscopy(LIBS) has attracted extensive attention as a new technique for in-situ marine application. In this work, the influence of deep-sea high pressure environment on LIBS signals was investigated by using a compact LIBS-sea system developed by Ocean University of China for the in-situ chemical analysis of seawater. The results from the field measurements show that the liquid pressure has a significant effect on the LIBS signals. Higher peak intensity and larger line broadening were obtained as the pressure increases. By comparing the variations of the temperature and salinity with the LIBS signals, a weak correlation between them can be observed. Under high pressure conditions, the optimal laser energy was higher than that in air environment. When the laser energy exceeded 17 mJ, the effect of laser energy on the signal intensity weakened. The signal intensity decreases gradually at larger delays. The obtained results verified the feasibility of the LIBS technique for the deep-sea in-situ detection, and we hope this technology can contribute to surveying more deep-sea environments such as the hydrothermal vent regions. 展开更多
关键词 LASER-INDUCED BREAKDOWN spectroscopy DEEP-SEA IN-SITU detection pressure effect plasma EMISSION
下载PDF
A low-cost in-situ CO_(2) sensor based on a membrane and NDIR for long-term measurement in seawater 被引量:2
6
作者 Meng LI Baolu DU +3 位作者 jinjia guo Zhihao ZHANG Zeyu LU Rong’er ZHENG 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2022年第3期986-998,共13页
The multi-point simultaneous long-term measurement of CO_(2) concentration in seawater can provide more-valuable data for further understanding of the spatial and temporal distribution of CO_(2).Thus,the requirement f... The multi-point simultaneous long-term measurement of CO_(2) concentration in seawater can provide more-valuable data for further understanding of the spatial and temporal distribution of CO_(2).Thus,the requirement for a low-cost sensor with high precision,low power consumption,and a small size is becoming urgent.In this work,an in-situ sensor for CO_(2) detection in seawater,based on a permeable membrane and non-dispersive infrared(NDIR)technology,is developed.The sensor has a small size(Ф66 mm×124 mm),light weight(0.7 kg in air),low power consumption(<0.9 W),low cost(<US$1000),and high-pressure tolerance(<200 m).After laboratory performance tests,the sensor was found to have a measurement range of(0–2000)×10^(-6),and the gas linear correlation R^(2) is 0.99,with a precision of about 0.98%at a sampling rate of 1 s.A comparison measurement was carried out with a commercial sensor in a pool for 7 days,and the results showed a consistent trend.Further,the newly developed sensor was deployed in Qingdao nearshore water for 35 days.The results proved that the sensor could measure the dynamic changes of CO_(2) concentration in seawater continuously,and had the potential to carry out long-term observations on an oceanic platform.It is hoped that the sensor could be applied to field ocean observations in near future. 展开更多
关键词 in-situ sensor dissolved CO_(2) long-term measurement permeable membrane non-dispersive infrared(NDIR) LOW-COST
下载PDF
Spectral characteristics of underwater laser-induced breakdown spectroscopy under high-pressure conditions
7
作者 Lintao WANG Ye TIAN +4 位作者 Ying LI Yuan LU jinjia guo Wangquan YE Ronger ZHENG 《Plasma Science and Technology》 SCIE EI CAS CSCD 2020年第7期28-35,共8页
Laser-induced breakdown spectroscopy(LIBS) has been proven to be an attractive technique for in situ oceanic applications.However,when applying LIBS into deep-sea,the pressure effect caused by different ocean depths i... Laser-induced breakdown spectroscopy(LIBS) has been proven to be an attractive technique for in situ oceanic applications.However,when applying LIBS into deep-sea,the pressure effect caused by different ocean depths is inescapable and could have great influence on the LIBS signals.In this work,spectral characteristics of underwater LIBS were investigated as a function of pressure in the range of 0.1-45 MPa.A high-pressure chamber built in the laboratory was used to simulate the high-pressure deep-sea environment.Optimal laser energy and detection delay were first determined under different pressure conditions and were shown to be independent of the external pressure.The increase in pressure has a significant impact both on the peak intensity and line broadening of the observed spectra.The peak intensity of Na,Li and K lines increases with the increasing pressure until a maximum intensity is reached at 12.5 MPa.Above this value,the peak intensity decreases gradually up to 45 MPa.For Ca line,the maximum intensity was observed at 30 MPa.The line broadening keeps constant at low pressures from 0.1-10 MPa,while it increases linearly at higher pressures,indicating a higher electron density caused by the compression effect of the high external pressure.We also compared the spectral data obtained from the high-pressure chamber and from the field sea trials,and the good consistency between the laboratory data and sea-trial data suggested the key role of pressure effect on underwater LIBS signals for practical deep-sea applications. 展开更多
关键词 underwater laser-induced breakdown spectroscopy spectral characteristics high-pressure chamber pressure effect deep-sea application
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部