Home Journals Articles Updates About
CN
image
收藏切换
Measuring 222Rn in aquatic environment via Pulsed Ionization Chamber Radon Detector
收藏切换
PDF
Lijun Song1, 2, 3, Wen Liu1, 2, 3, Shibin Zhao1, 2, 3, Chunqian Li4, 5, Jinjia Guo4, Natasha Dimova6, Bochao Xu1, 2, *
Acta Oceanologica Sinica | 2023, 42(8) : 185 - 189
Less
收藏切换
Acta Oceanologica Sinica | 2023, 42(8): 185-189
• Articles •
Measuring 222Rn in aquatic environment via Pulsed Ionization Chamber Radon Detector
Full
Lijun Song1, 2, 3, Wen Liu1, 2, 3, Shibin Zhao1, 2, 3, Chunqian Li4, 5, Jinjia Guo4, Natasha Dimova6, Bochao Xu1, 2, *
Affiliations
  • 1 Frontiers Science Center for Deep Ocean Multispheres and Earth System/Key Laboratory of Marine Chemistry Theory and Technology of Ministry of Education, Ocean University of China, Qingdao 266100, China
  • 2 Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
  • 3 College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
  • 4 College of Information Science and Engineering, Ocean University of China, Qingdao 266100, China
  • 5 R & D Center for Marine Instruments and Apparatuses, Qingdao Marine Science and Technology Center, Qingdao 266200, China
  • 6 Department of Geological Sciences, College of Arts and Sciences, University of Alabama, Tuscaloosa 35487, USA
Published: 2023-08-25 doi: 10.1007/s13131-023-2183-9
Outline
收藏切换

Radon (Rn) is a naturally occurring radioactive inert gas in nature, and 222Rn 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 222Rn in discrete water samples with a wide range of 222Rn 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.

222Rn  /  radon measurement  /  Pulsed Ionization Chamber Radon Detector  /  radon in discrete water samples  /  submarine groundwater discharge
Lijun Song, Wen Liu, Shibin Zhao, Chunqian Li, Jinjia Guo, Natasha Dimova, Bochao Xu. Measuring 222Rn in aquatic environment via Pulsed Ionization Chamber Radon Detector[J]. Acta Oceanologica Sinica, 2023 , 42 (8) : 185 -189 . DOI: 10.1007/s13131-023-2183-9
Full Text
Less
1 Introduction
Less
Radon (Rn) is a naturally occurring radioactive inert gas in nature. Inhalation or intake of radon will cause harm to human body. Radon accumulation in groundwater in high levels is an essential concern and it requires comprehensive monitoring in the environment (Zhao, 1993). According to published literature, the concentration range of 222Rn in natural waters is significant (between 10−5 Bq/L and 20 Bq/L) with groundwater’s levels 3−4 orders of magnitude higher than that of typical surface water (Broecker et al., 1967; Burnett et al., 2001; Cook et al., 2003; D’Alessandro and Vita, 2003; Guo et al., 2020). On the other hand, 222Rn, with a half-life of 3.82 d, has been widely used as a robust tracer for assessing natural processes on time scales of 20 d, such as submarine groundwater discharge (SGD) and air-sea gas exchange fluxes, to mention a few (Baskaran, 2016; Cable et al., 1996; Lambert and Burnett, 2003; Savatier and Rocha, 2021; Seo and Kim, 2021; Yu et al., 2020; Zhang et al., 2016).
Currently, the most utilized instruments used to evaluate 222Rn in natural waters include radon line emanation counter, RAD7 radon analyzer, and Pulsed Ionization Chamber (PIC) Radon Detector, etc. The “radon line emanation” technique was widely used in the 70s and 80s, 20th century. The background of the system is relatively low and the counting efficiency is high (theoretically to be 300%). This allowed using it for radon investigations in the open ocean since the GEOSECS era (Key et al., 1979). However, this system requires liquid nitrogen for concentrating the radon gas and high-purity helium as the carrier gas, which would often limit its on-site application. At the beginning of this century, a new automated radon-in-air analyzer called RAD7 was assembled with grab water samples and has been widely used currently to test the radon activities in discrete groundwater samples (Kim et al., 2001). The same radon detector can also be equipped with proper accessories and adopted to measure radon activities continuously in large variety of aquatic environments such as rivers and streams, estuaries, bays and other coastal settings (Baskaran, 2016; Burnett et al., 2001; Schmidt et al, 2008). However, the RAD7 has some limitations, one being maintaining relatively low humidity (RH%) inside the chamber (<10%) to ensure higher test efficiency (Kim et al., 2001). This could be often limiting when processing large number of samples. Another disadvantage is the relatively high price of the RAD7 unit, especially for developing countries. The later had limited groundwater explorations using radon and a tracer in these parts of the world.
Recently, a new cheaper and more robust method for measuring radon in water using a PIC was proposed (Seo and Kim, 2021). The PIC technique offers high detection efficiency and sensitivity to radon variations. Since PIC counts electrons produced by air ionization, detection efficiency will not be affected by humidity (Gavrilyuk et al., 2015; Seo and Kim, 2021).
In this work, we further investigate the performance of the PIC technique under large range of 222Rn activities that are observed in natural groundwater and seawater. This piece of knowledge will highly benefit not only the groundwater research community, but also government institutions who monitor radon activities in natural waters with radiological health protection purposes.
2 Method
Less
2.1 Instrument and principle
The principle of detection of radon in gas phase has been described elsewhere (http://www.radonftlab.com). Briefly, a PIC Radon Detector is comprised a stainless chamber and a counting probe installed beneath the center of the top cover, which are negatively charged and positively charged respectively. Alpha (α) particles produced by radon radioactive decay ionize air in the ionization chamber to form electron ion pairs, which are gathered and counted by the PIC counter. The pulse electrical signal is converted into digital signal which is proportionally correlated with radon concentration (Seo and Kim, 2021).
More specifically, the experimental device in this study includes (1) an ionization chamber (200 mL), (2) air pump, and (3) the sample bottle (Fig. 1). If the inlet and outlet of the PIC counter are closed, the system will be sealed as a closed loop. When testing samples, a micro filtration membrane (0.45 μm) is placed in the upper stream of the PIC counter to prevent dust entering the chamber. We obtained the data using a self-designed software. Details about the software could be found in Li et al. (2022).
Theoretically, PIC Radon Detector measures the activities of all radon isotopes, including 222Rn, 220Rn and 219Rn. However, the natural abundance of 219Rn is very low because of its very short half-life of 3.96 s, so contribution from 219Rn counting should be negligible to the total counts. The half-life of 220Rn is 55.6 s, and it can decay completely in 5 min when unsupported. The half-life of 222Rn is 3.82 d, which is longer than that of the other two radon isotopes. Hence, the activity of 222Rn can be distinguished based on the difference of half-lives among the three radon nuclides.
2.2 Preparation of standard and blank samples
To evaluate the overall sensitivity of the system, describing in Fig. 1, we prepared several standard solutions with known amount of radon in the water. We used a standard solution of 226Ra with traceable activity concentration 1 000 Bq/L. Since the half-life of 226Ra (T1/2=1 600 a) is much longer than the half-life of 222Rn, the activity of the parent equals its daughter after five times of daughter’s half-life according to the principle of secular equilibrium. Therefore, the concentration of dissolved 222Rn in the standard solution equals the concentration of 226Ra.
For these standards, we used natural seawaters which was filtered through Mn-fibers to remove naturally dissolved 226Ra (Moore, 1976). A known amount of 226Ra standard solution was then added to the radium free seawater to produce a series of standard samples, with volumes of 250 mL, 500 mL and 5 L, based on the size of the bottles. For the bottle with volume of 500 mL, six sub-samples were prepared with activity gradient of 0.04−0.8 Bq to evaluate the counting efficiency of the method. The pH of the standard seawater sample was adjusted to about 8 with ammonia solution. Before testing, water samples were purged with high-purity helium gas to remove any residual dissolved radon in the prepared solutions. One blank sample was also prepared following the same procedure but without the radium spike added. All the samples were then sealed for 7−10 d to allow the radon ingrowth to levels that would be detectable by the system.
2.3 Protocol of water sample analysis
Before each sample (or standard) test, the PIC counter was purged with helium gas to remove residual radon in the instrument. The bottles filled with water sample were then connected in the loop as shown in Fig. 1. We let the air pump turned on and run for 2 h to ensure radon was degassed completely from water and homogenously distributed in the system. The water samples were then removed, and the PIC counter was sealed for 5 min to let 220Rn in the enclosed volume completely decay. The PIC counter was then reset and measured the activity of 222Rn continuously for 2−3 h with 10 min data reporting interval. An experiment was considered completed when total counts were higher than 1 000, resulting in a counting error of <3%. If the sample activity is relatively low, the counting time was extended accordingly.
2.4 Instrument background test
To assess the detection limit of the system, the instrument background was tested. Immediately before this test, the system was purged with high-purity helium gas for about 1 min to remove the residual air in the PIC Radon Detector. The PIC was then sealed by quickly closing the inlet and outlet valves of the chamber (Fig. 1). The background of the instrument was then counted continuously for 24 h at an interval of 10 min to get a good understand of instrument background, which standard deviation could be used to calculate the detection limit.
2.5 Aeration time test
The required time for complete degassing of radon from water (i.e., the sparging times) is an important parameter when evaluating the efficiency of the method. We tested four different aeration times, 1 h, 1.5 h, 2 h and 3 h. Count rates were recorded while pump was optional in a certain sparging times condition. Counting statistics were obtained after 400 min counting time at an interval of 10 min.
2.6 Sample collection and measurement
To test the system, on a monthly basis form October 2021 to December 2021, we collected a total of 7 shallow groundwater samples (250 mL) and 2 seawater samples (500 mL) from the tidal flat of the west bank of Jiaozhou Bay, China. To compare the performance of our new system duplicates of groundwater samples was simultaneously measured by both PIC and RAD7-H2O. The PIC method was developed by this study with details described in Section 2.4. The RAD7 method is combined with its H2O accessory, with more details reported by Lee and Kim (2006).
To verify the test precision of the PIC method, a standard sample with volume of 500 mL and activity of 0.4 Bq/L were prepared in the laboratory based on the method described in Section 2.2. The sample was repeatedly measured for eleven times and the method precision was evaluated based on the standard deviation.
3 Results
Less
3.1 Instrument background
Within 24 h counting, the instrument background value range of 0−0.08 cpm (counts per minute) as shown in Fig. 2, with an average of (0.04±0.02) cpm (n=143). The detection limit of the instrument is considered as three times of standard deviation, so the detection limit of the PIC method established in this study is 0.07 cpm.
3.2 Sparging times
The results based on different sparging times are shown in Fig. 3. The results show that radon degassing benefits from longer sparging times up to 2 h. We found that there was no statistical difference between sparging times of 2 h and 3 h. By averaging the count rates of the platform period, the average value was (2.1±0.3) cpm (n=39) when the sparging time was 1 h, (2.5±0.2) cpm (n=39) for a sparging time of 1.5 h, (3.1±0.2) cpm (n=39) and (3.0±0.2) cpm (n=39) when the sparging times were 2 h and 3 h, respectively. When we compared the data from the three experiments lower degassing efficiency and greater variation were found when the sparging time was shorter. Longer than 2 h sparging times did not contribute to significant radon degassing. Based on these results, we suggest that 2 h is an optimum sparging time for this method.
3.3 Method efficiency and precision
The result from counting the blank sample, (0.04±0.03) cpm, indicated that it was consistent with the instrument background value ((0.04±0.02) cpm), i.e., the blank sample had no radium and radon.
The results from analyzing the system efficiency using the prepared standard samples with a volume of 500 mL are presented in Fig. 4. Each standard was measured twice. Based to the slope of the linear fitting line, the efficiency of this particular PIC and sample of 500 mL water sample is 6.06 cpm for 1 Bq/L. We recommend that users conduct similar experiments when determine the efficiency of their own equipment.
To evaluate the relationship between the overall system efficiency with sample volumes, the same PIC system was used to test the efficiency of sample volumes of 250 mL, 500 mL and 5 L samples. Each sample was measured twice, and results are shown in Fig. 5. It can be seen from the figure that with the increase of sample bottle volume, the test efficiency of the instrument also increases following a good logarithmic relationship (R2=0.994).
In order to evaluate the test precision of the method, with a sample total activity of 0.2 Bq of 226Ra was tested 11 times, and the results are shown in Fig. 6. The average activity of the 11 tests is (2.1±0.1) cpm, and the relative standard deviation is 6%. The test precision of the method is 6%, which is feasible for determining 222Rn activity in aquatic environment.
3.4 Natural waters sample measurements
For groundwater samples and surface seawater samples collected from the Jiaozhou Bay, the activity of 222Rn in the parallel samples was tested with the PIC Radon Detector and a RAD7. The test results are shown in Table 1. Because 222Rn concentration in groundwater is high, bottle volume size of 250 mL was used for groundwater sample analysis. Results of the PIC on the two parallel sample 222Rn in groundwater were consistent with the RAD7 result but with lower uncertainty. In another occasion, two months later, we collected a second set of groundwater samples, and the test results of PIC were consistent with those of RAD7.
For surface seawater, considering low 222Rn concentration and sufficient water volume for collection, water volume of 500 mL was used for sample collection and analysis. The 222Rn concentration in the seawater sample collected in November 2021 measured by PIC and RAD7, and the result matched well with each other.
4 Discussion
Less
We found that the detection limit of PIC Radon Detector used in this study is 0.07 cpm. According to the detection limit of the instrument and the efficiency value of the instrument under different volumes, when the sample volume is 250 mL, the detection limit of the measured aquatic 222Rn concentration would be 0.021 Bq/L, which is feasible for almost all groundwater samples. In the case of sample volume of 500 mL, the detection limit of the instrument is 0.012 Bq/L, which could be used for groundwater 226Ra measurement after secular equilibrium. If the sample volume increased to 5 L, the detection limit of the instrument would decrease to 0.005 2 Bq/L, which will be valid for most of the river, estuary and coastal sea settings. Therefore, when the PIC method applied to the actual sample in different 222Rn concentration scenarios, the appropriate sample volume can be selected according to the approximate activity of the sample. Radon activity in groundwater is relatively high, ranging from a few to hundreds of Becquerel per litre. For example, radon concentration in groundwater of the lower Huanghe River ranges from 0.14−11.67 Bq/L (Zhang et al., 2018). In Tuticorin District of Tamil Nadu, the activity of radon concentration in groundwater in India ranges from 0.070−40.7 Bq/L (Singaraja et al., 2016). When testing such groundwater with high radon activity, the system with 250 mL sample volume can be selected for testing. Estuarine areas or inshore sea areas with low radon activity, such as the coastal areas of Vizhinjam, Thiruvananthapuram and Kerala, have a radon activity of (0.0120±0.001 7) Bq/L (Jacob et al, 2009). The radon activity in the bottom water of the Changjiang River Estuary is 0.008 2−0.15 Bq/L (Guo et al., 2020). In the Yellow-Bohai Sea, the activity of surface water is 0.005 5−0.077 Bq/L, and that of bottom water is 0.005 7−0.062 Bq/L (Wang et al., 2021). A sample volume of 500 mL or 5 L can be selected for testing according to the radon activity in natural water. If the radon activity in water is very low, larger sample volumes can be selected for testing.
Drinking water is a fundamental resource for human life. 222Rn is the most dangerous radon isotope due to its relatively long half-life and more quantity of radioactive decay products. Moreover, 222Rn has long-lived decay products 210Pb (22.3 a) and 210Po (138.4 d) possessing long elimination periods in human body (Cantaluppi et al., 2021; Kelleher et al., 2017). The relationship between different volume efficiency of the PIC Radon Detector can be used to monitor 222Rn in drinking water, which is of great significance for us to test the activities of radioactive radon in drinking water, avoid human exposure to radiation due to inhalation or intake of excessive radioactive substances, and protect people’s health.
5 Conclusions
Less
In this study, the PIC Radon Detector used has a low background value, and the radon in the gas path reaches equilibrium after 2 h of aeration. Through efficiency correction, the efficiency of the test system with water volume of 500 mL is 6.06 cpm for 1 Bq/L. The efficiency is related to the volume of the system volume, the counting efficiency of PIC and other factors. There will be differences in the test efficiency between different systems. Therefore, each set of the test system needs to be calibrated before testing samples.
Good logarithmic correlations were found between sample volume and efficiency. Water volume of 250 mL would be sufficient for analysis of most of groundwater samples. If the sample volume increased to 5 L, the PIC method will be valid for most of the river, estuary and coastal sea settings. According to the comparison analysis, there is no significant difference between PIC Radon Detector and RAD7 in sample test. Considering not affected by humidity and easy to operate, PIC Radon Detector is recommended to be used as the analysis instrument of 222Rn in aquatic settings.
Funding
Less
  • The National Natural Science Foundation of China under contract Nos 42130410, 41876075 and U1906210; the Fundamental Research Funds for the Central Universities under contract No. 201962003.
References
Less
Baskaran M. 2016. Radon: A Tracer for Geological, Geophysical and Geochemical Studies. Cham: Springer, 1–254
Broecker W S, Li Yuanhui, Cromwell J. 1967. Radium-226 and radon-222: concentration in Atlantic and Pacific Oceans. Science, 158(3806): 1307–1310, doi: 10.1126/science.158.3806.1307
Burnett W C, Kim G, Lane-Smith D. 2001. A continuous monitor for assessment of 222Rn in the coastal ocean. Journal of Radioanalytical and Nuclear Chemistry, 249(1): 167–172, doi: 10.1023/A:1013217821419
Cable J E, Burnett W C, Chanton J P, et al. 1996. Estimating groundwater discharge into the northeastern Gulf of Mexico using radon-222. Earth and Planetary Science Letters, 144(3–4): 591–604
Cantaluppi C, Zannoni D, Cianchi A, et al. 2021. Methods for radioactivity measurements in drinking water using gamma spectrometry. Journal of Environmental Radioactivity, 232: 106566, doi: 10.1016/j.jenvrad.2021.106566
Cook P G, Favreau G, Dighton J C, et al. 2003. Determining natural groundwater influx to a tropical river using radon, chlorofluorocarbons and ionic environmental tracers. Journal of Hydrology, 277(1–2): 74–88
D’Alessandro W, Vita F. 2003. Groundwater radon measurements in the Mt. Etna area. Journal of Environmental Radioactivity, 65(2): 187–201, doi: 10.1016/S0265-931X(02)00096-6
Gavrilyuk Y M, Gangapshev A M, Gezhaev A M, et al. 2015. High-resolution ion pulse ionization chamber with air filling for the 222Rn decays detection. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 801: 27–33
Guo Xiaoyi, Xu Bochao, Burnett W C, et al. 2020. Does submarine groundwater discharge contribute to summer hypoxia in the Changjiang (Yangtze) River Estuary?. Science of The Total Environment, 719: 137450
Jacob N, Babu D S D, Shivanna K. 2009. Radon as an indicator of submarine groundwater discharge in coastal regions. Current Science, 97(9): 1313–1320
Kelleher K, Wong J, León-Vintró L, et al. 2017. International Rn-222 in drinking water interlaboratory comparison. Applied Radiation and Isotopes, 126: 270–272, doi: 10.1016/j.apradiso.2017.01.036
Key R M, Guinasso N L Jr, Schink D R. 1979. Emanation of radon-222 from marine sediments. Marine Chemistry, 7(3): 221–250, doi: 10.1016/0304-4203(79)90041-0
Kim G, Burnett W C, Dulaiova H, et al. 2001. Measurement of 224Ra and 226Ra activities in natural waters using a radon-in-air monitor. Environmental Science & Technology, 35(23): 4680–4683
Lambert M J, Burnett W C. 2003. Submarine groundwater discharge estimates at a Florida coastal site based on continuous radon measurements. Biogeochemistry, 66(1–2): 55–73
Lee J M, Kim G. 2006. A simple and rapid method for analyzing radon in coastal and ground waters using a radon-in-air monitor. Journal of Environmental Radioactivity, 89(3): 219–228, doi: 10.1016/j.jenvrad.2006.05.006
Li Chunqian, Zhao Shibin, Zhang Chenglun, et al. 2022. Further refinements of a continuous radon monitor for surface ocean water measurements. Frontiers in Marine Science, 9:1047126
Moore W S. 1976. Sampling 228Ra in the deep ocean. Deep-Sea Research and Oceanographic Abstracts, 1976, 23(7): 647–651
Savatier M, Rocha C. 2021. Rethinking tracer-based (Ra, Rn, salinity) approaches to estimate point-source submarine groundwater discharge (SGD) into coastal systems. Journal of Hydrology, 598: 126247, doi: 10.1016/j.jhydrol.2021.126247
Schmidt A, Schlueter M, Melles M, et al. 2008. Continuous and discrete on-site detection of radon-222 in ground- and surface waters by means of an extraction module. Applied Radiation and Isotopes, 66(12): 1939–1944, doi: 10.1016/j.apradiso.2008.05.005
Seo J, Kim G. 2021. Rapid and precise measurements of radon in water using a pulsed ionization chamber. Limnology and Oceanography: Methods, 19(4): 245–252, doi: 10.1002/lom3.10419
Singaraja C, Chidambaram S, Jacob N, et al. 2016. Radon levels in groundwater in the Tuticorin district of Tamil Nadu, South India. Journal of Radioanalytical and Nuclear Chemistry, 307(2): 1165–1173, doi: 10.1007/s10967-015-4312-1
Wang Xiaoxiong, Chen Xiaogang, Liu Jianan, et al. 2021. Radon traced seasonal variations of water mixing and accompanying nutrient and carbon transport in the Yellow-Bohai Sea. Science of The Total Environment, 784: 147161, doi: 10.1016/j.scitotenv.2021.147161
Yu Zhongbo, Li Minjuan, Liu Yunchen, et al. 2020. Study on hydraulic exchange of river water and groundwater based on radon isotope. Journal of Hohai University: Natural Sciences (in Chinese), 48(1): 8–13
Zhang Xiaojie, Xu Bochao, Xia Dong, et al. 2016. Using natural radium and radon isotopes trace the water transport process and nutrients distribution in the Yellow River Estuary under the influence of the Water-Sediment Regulation Scheme. Haiyang Xuebao (in Chinese), 38(8): 36–43
Zhang Xiaojie, Xu Xiaohan, Xiang Zhanchang, et al. 2018. Distribution characteristics and influence factors of radium and radon isotopes in the lower reaches of the Yellow River. Marine Environmental Science (in Chinese), 37(1): 1–7
Zhao Chongde. 1993. Determination of 222Rn in the water. Atomic Energy Science and Technology (in Chinese), (1): 62–65
Appendix
Less
Year 2023 volume 42 Issue 8
PDF
49
27
Cite this Article
BibTeX
Article Info
doi: 10.1007/s13131-023-2183-9
  • Receive Date：2022-06-22
  • Online Date：2025-11-22
  • Published：2023-08-25
Article Data
Affiliations
History
  • Received：2022-06-22
  • Accepted：2022-08-15
Funding
The National Natural Science Foundation of China under contract Nos 42130410, 41876075 and U1906210; the Fundamental Research Funds for the Central Universities under contract No. 201962003.
Affiliations
    1 Frontiers Science Center for Deep Ocean Multispheres and Earth System/Key Laboratory of Marine Chemistry Theory and Technology of Ministry of Education, Ocean University of China, Qingdao 266100, China
    2 Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
    3 College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
    4 College of Information Science and Engineering, Ocean University of China, Qingdao 266100, China
    5 R & D Center for Marine Instruments and Apparatuses, Qingdao Marine Science and Technology Center, Qingdao 266200, China
    6 Department of Geological Sciences, College of Arts and Sciences, University of Alabama, Tuscaloosa 35487, USA

Corresponding:

* E-mail:
References
Share
https://castjournals.cast.org.cn/joweb/aos/EN/10.1007/s13131-023-2183-9
Share to
QR

Scan QR to access full text

Cite this article
BibTeX
Citations
表12种不同金属材料的力学参数
科
Family		 属数
Number of
genus		 种数
Number of
species		 占总种数比例
Percentage of
total species (%)		 属
Genus		 种数
Number of
species		 占总种数比例
Percentage of total
species (%)
鹅膏菌科Amanitaceae 2 11 5.26 鹅膏菌属 Amanita 10 4.78
小菇科 Mycenaceae 2 12 5.74 丝盖伞属 Inocybe 5 2.39
多孔菌科 Polyporaceae 8 14 6.70 蜡蘑属 Laccaria 5 2.39
红菇科 Russulaceae 3 23 11.00 小皮伞属 Marasmius 6 2.87
小菇属 Mycena 11 5.26
光柄菇属 Pluteus 5 2.39
红菇属 Russula 17 8.13
栓菌属 Trametes 5 2.39
关闭全屏
  • BibTeX
  • EndNote
  • RefWorks
  • TxT
Links
Articles
Latest Articles
Most Read
Collections
Updates
Events
News
Multimedia
About
About Us
Contact
No. 86 Xueyuan South Road, Haidian District, Beijing
100081
010-62199257
qkjq@cast.org.cn

Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House