Tritium breeder and neutron multiplier as functional materials play an important role not only in ITER test blanket module （TBM） but also in fusion reactor. The paper describes the status of the fabrication of the t...Tritium breeder and neutron multiplier as functional materials play an important role not only in ITER test blanket module （TBM） but also in fusion reactor. The paper describes the status of the fabrication of the two materials in Southwestern Institute of Physics （SWIP）. Li4SiO4 pebbles were fabricated by melt-spraying method. Most of the pebbles with the diazneter of 1.0 mm are well spherically shaped. The properties of the pebbles have been investigated. The results show that the pebbles produced by this method have a high density of 93% TD （theoretical density）. It was also found that the open/closed porosity will be decreased after thermal treatment, but the average crush load will be increased to 7 N. The rotating electrode process （REP） has been adopted to produce beryllium pebble for impurity control and mass production. The pebbles with the diameter of 1.0 mm were produced by REP. The beryllium pebbles produced by REP look almost perfectly spherical with a very smooth surface and a high density of 98% TD. The test results indicate that REP method has excellent prospects for the fabrication of beryllium pebbles and the attractiveness of their properties.展开更多
Most of the foreign bodies detected in adult gastroin- testinal systems are accidentally swallowed pins. In this study, we presented a case with intracolonic multiple pebbles. A 20-year-old man was admitted to emergen...Most of the foreign bodies detected in adult gastroin- testinal systems are accidentally swallowed pins. In this study, we presented a case with intracolonic multiple pebbles. A 20-year-old man was admitted to emergency surgery policlinic for abdominal pain for 2 d without any alleviation or aggravation. His upright plain abdominal radiographic imaging revealed about 30-40 overt dense opacities in lumen of colonic segments, with oval and well shaped contours, each approximately 1 cm × 1 cm in size. The multiplanar reconstructions and three- dimensional images combined with sectional screening showed that all pebbles had passed completely into the colon and no foreign bodies had remained in the ileal segments. On psychiatric assessment, he was found to have immature personality features, difficulty in over- coming stressors and adaptation disorder. He recovered by conservative management and radiographic monitoring applied during his follow-up. Thus, it can be concluded that, in differential diagnosis of abdominal pain in adult ages, though less frequently seen than in children, gastrointestinal system foreign bodies should always be kept in mind and it should be considered that ingestion of pebbles may be one of the factors contributing to abdominal pain particularly in young adults with psychiatric problems. In such cases suspected of having foreign bodies which cannot be detected by plain films, abdominal tomography can be an alternative for diagnostic imaging.展开更多
Eclogite pebbles are first discovered in late Jurassic conglomerates of the Fenghuangtai Formation from the northern foot of the Dabie Mountains, eastern China. The eclogite shows relatively strong retrograde metamor-...Eclogite pebbles are first discovered in late Jurassic conglomerates of the Fenghuangtai Formation from the northern foot of the Dabie Mountains, eastern China. The eclogite shows relatively strong retrograde metamor-phism. The major remnant minerals are garnet, phengite, quartz, rutile, clinozoisite, fingerprint(or worm)-form sym-plectite and pseudomorphic enclosure of coesite in garnet. End-member components of the garnet mainly made up of grossular (27.7%-37.8%), almandinc (45.5%-49.0%) and pyrope (12.3%-25.7%). End-member components of the pyrope is less than 30%, i.e. equivalent to C type eclogite. Si-cations of the phengite are 3.44-3.54 p.f.u. (taking O=11as standard). It is estimated that the pressures are 2.5-3.2 GPa, the temperatures are 600-900℃. Discovery of the eclogite pebbles in the late Jurassic conglomerates from the northern foot of the Dabie Mountains suggests that the HP-UHP metamorphic rocks of the Dabie Mountains, which were formed in Triassic, had been exposed to the surface in展开更多
Recently, there has been a growing interest in gait retraining to alter the gait parameters of different populations.In these gait retraining, peak plantar pressure (PPP) was considered as an important parameter of th...Recently, there has been a growing interest in gait retraining to alter the gait parameters of different populations.In these gait retraining, peak plantar pressure (PPP) was considered as an important parameter of the footbiomechanics. It has been found that high PPP correlates to the common foot deformities including pes planus/cavus. However, previous studies utilized excessive electronics in gait retraining, which is challenging toimplement daily especially when device cleaning, flexibility and portability are considered. Therefore, this studyinvestigated feasibility of a novel unpowered gait retraining for reducing high PPP. Twelve potential participantsidentified for investigation through a baseline PPP evaluation with Novel Pedar-x system. Participants received asingle session for the gait retraining with pebbles in the form of rigid spherical inserts (RSI) placed in locations ofhigh PPP inside the deformable insole. This provides tactile cues alerting the participants to alter their gait toreduce excess PPP. The PPP values were tracked in weekly follow-up sessions for 6 weeks. The results demonstrated that participants responded to RSI altering their gait to reduce PPP and maximum force by 14% and 10.5%after six weeks respectively. This study is valuable for physicians in reducing PPP when non-electronics arerequired.展开更多
To elucidate the wear mechanisms of the scraper in shield tunneling through sandy pebble strata,this study aims to achieve high efficiency and low wear during the tunneling process.We evaluate the operational paramete...To elucidate the wear mechanisms of the scraper in shield tunneling through sandy pebble strata,this study aims to achieve high efficiency and low wear during the tunneling process.We evaluate the operational parameters and tool wear characteristics of a 9-m diameter spoke-type shield machine used on the Beijing Daxing Airport Line.The analysis focuses on the wear values of the scrapers and rippers,wear of the scraper in different wear forms,and scraper wear relative to the position of the rippers obtained from the field.The study yielded the following conclusions.The wear values of scrapers on different spokes vary significantly owing to ripper protection.The wear of the scrapers can be categorized into six types:tooth chipping,local damage of teeth,wear of side teeth,wave-type of wear,wear on intermediate teeth,and flat wear,with the majority exhibiting wear on the side and intermediate teeth.The 0°spoke maintained the initial shape of the scrapers,making it more suitable for tunneling in sandy pebble strata.Based on the differences in the relative positions of the ripper and scraper,a model is proposed to determine the ripper plowing influence area.It was found that this area depends on the geological conditions of the soil;thus,the influence angle of ripper plowing in the considered sandy pebble strata is determined to be between 35°and 50°.The results obtained in this study provide a theoretical reference for optimizing scraper layouts in shield construction,even when operating under varying geological conditions.展开更多
X-ray fluorescence(XRF)sensor-based ore sorting enables efficient beneficiation of heterogeneous ores,while intraparticle heterogeneity can cause significant grade detection errors,leading to misclassifications and hi...X-ray fluorescence(XRF)sensor-based ore sorting enables efficient beneficiation of heterogeneous ores,while intraparticle heterogeneity can cause significant grade detection errors,leading to misclassifications and hindering widespread technology adoption.Accurate classification models are crucial to determine if actual grade exceeds the sorting threshold using localized XRF signals.Previous studies mainly used linear regression(LR)algorithms including simple linear regression(SLR),multivariable linear regression(MLR),and multivariable linear regression with interaction(MLRI)but often fell short attaining satisfactory results.This study employed the particle swarm optimization support vector machine(PSO-SVM)algorithm for sorting porphyritic copper ore pebble.Lab-scale results showed PSO-SVM out-performed LR and raw data(RD)models and the significant interaction effects among input features was observed.Despite poor input data quality,PSO-SVM demonstrated exceptional capabilities.Lab-scale sorting achieved 93.0%accuracy,0.24%grade increase,84.94%recovery rate,57.02%discard rate,and a remarkable 39.62 yuan/t net smelter return(NSR)increase compared to no sorting.These improvements were achieved by the PSO-SVM model with optimized input combinations and highest data quality(T=10,T is XRF testing times).The unsuitability of LR methods for XRF sensor-based sorting of investigated sample is illustrated.Input element selection and mineral association analysis elucidate element importance and influence mechanisms.展开更多
Sedimentary process research is of great significance for understanding the distribution and characteristics of sediments.Through the detailed observation and measurement of the Sangyuan outcrop in Luanping Basin,this...Sedimentary process research is of great significance for understanding the distribution and characteristics of sediments.Through the detailed observation and measurement of the Sangyuan outcrop in Luanping Basin,this paper studies the depositional process of the hyperpycnal flow deposits,and divides their depositional process into three phases,namely,acceleration,erosion and deceleration.In the acceleration phase,hyperpycnal flow begins to enter the basin nearby,and then speeds up gradually.Deposits developed in the acceleration phase are reverse.In addition,the original deposits become unstable and are taken away by hyperpycnal flows under the eroding force.As a result,there are a lot of mixture of red mud pebbles outside the basin and gray mud pebbles within the basin.In the erosion phase,the reverse deposits are eroded and become thinner or even disappear.Therefore,no reverse grading characteristic is found in the proximal major channel that is closer to the source,but it is still preserved in the middle branch channel that is far from the source.After entering the deceleration phase,normally grading deposits appear and cover previous deposits.The final deposits in the basin are special.Some are reverse,and others are normal.They are superimposed with each other under the action of hyperpycnal flow.The analysis of the Sangyuan outcrop demonstrates the sedimentary process and distribution of hyperpycnites,and reasonably explain the sedimentary characteristics of hyperpycnites.It is helpful to the prediction of oil and gas exploration targets in gravity flow deposits.展开更多
基于计算流体力学(Computational Fluid Dynamics,CFD)通用计算程序Fluent,研究了模块化熔盐冷却球床堆(Pebble Bed Advanced High Temperature Reactor,PB-AHTR)中心热通道稳态热工水力行为。利用已开发的多孔介质流固两相局域非热平...基于计算流体力学(Computational Fluid Dynamics,CFD)通用计算程序Fluent,研究了模块化熔盐冷却球床堆(Pebble Bed Advanced High Temperature Reactor,PB-AHTR)中心热通道稳态热工水力行为。利用已开发的多孔介质流固两相局域非热平衡模型计算了球床堆中的压降、冷却剂的温场分布以及固相球床的温场分布,计算并比较了不同的多孔介质阻力因子(Ergun与KTA)对通道内的冷却剂流动以及温场分布的影响,并对丧失部分冷却剂情况下通道内的冷却剂及燃料温度进行了计算分析。结果表明使用不同的阻力因子对堆芯压降计算结果和流场的分布影响较大;而冷却剂温场及固相球床温场和球心的温度分布在不同的阻力因子下的差别较小,在PB-AHTR的设计参数下堆芯产生的热量能够被有效的输出,设计具有较大的安全裕度。计算结果对于球床堆的优化设计提供了一定的参考价值。展开更多
The Gan-Hang Belt in Southeast China is characterized by several igneous and siliciclastic basins associated with crustal extension during Late Mesozoic. The sedimentary evolution of the red basins is still poorly und...The Gan-Hang Belt in Southeast China is characterized by several igneous and siliciclastic basins associated with crustal extension during Late Mesozoic. The sedimentary evolution of the red basins is still poorly understood. In this study, sedimentary fades analysis and pebble counting were performed on outcrop sections of the Late Cretaceous Guifeng Group in the Yongfeng-Chongren Basin in central Jiangxi Province. Thirty-five conglomerate outcrops were chosen to measure pebble lithology, size, roundness, weathering degree and preferred orientation. Results show that gravels are mostly fine to coarse pebbles and comprise dominantly quartzites, metamorphic rocks, granitoids and sandstones. Rose diagrams based on imbricated pebbles indicate variable paleocurrent directions. Combining with typical sedimentary structures and vertical successions, we suggest that the Guifeng Group were deposited in alluvial fan, river and playa lake depositional systems. The proposed depositional model indicates that the Hekou Formation represents the start-up stage of the faulted basin, accompanied by sedimentation in alluvial fan and braided river environments. Then this basin turned into a stable expansion stage during the deposition of the Tangbian Formation. Except for minor coarse sediments at the basin margin, the other area is covered with fine-grained sediments of lake and river environments. The Lianhe Formation, however, is once again featured by conglomerates, suggesting a probable tectonic event. Therefore, the study region possibly suffered two tectonic events represented by the conglomerates of the Hekou and Lianhe formations in the context of the crustal extension in Southeast China.展开更多
基金supported by the Major State Basic Research Development Program of China (973 Program) (No.2009GB108000)
文摘Tritium breeder and neutron multiplier as functional materials play an important role not only in ITER test blanket module （TBM） but also in fusion reactor. The paper describes the status of the fabrication of the two materials in Southwestern Institute of Physics （SWIP）. Li4SiO4 pebbles were fabricated by melt-spraying method. Most of the pebbles with the diazneter of 1.0 mm are well spherically shaped. The properties of the pebbles have been investigated. The results show that the pebbles produced by this method have a high density of 93% TD （theoretical density）. It was also found that the open/closed porosity will be decreased after thermal treatment, but the average crush load will be increased to 7 N. The rotating electrode process （REP） has been adopted to produce beryllium pebble for impurity control and mass production. The pebbles with the diameter of 1.0 mm were produced by REP. The beryllium pebbles produced by REP look almost perfectly spherical with a very smooth surface and a high density of 98% TD. The test results indicate that REP method has excellent prospects for the fabrication of beryllium pebbles and the attractiveness of their properties.
文摘Most of the foreign bodies detected in adult gastroin- testinal systems are accidentally swallowed pins. In this study, we presented a case with intracolonic multiple pebbles. A 20-year-old man was admitted to emergency surgery policlinic for abdominal pain for 2 d without any alleviation or aggravation. His upright plain abdominal radiographic imaging revealed about 30-40 overt dense opacities in lumen of colonic segments, with oval and well shaped contours, each approximately 1 cm × 1 cm in size. The multiplanar reconstructions and three- dimensional images combined with sectional screening showed that all pebbles had passed completely into the colon and no foreign bodies had remained in the ileal segments. On psychiatric assessment, he was found to have immature personality features, difficulty in over- coming stressors and adaptation disorder. He recovered by conservative management and radiographic monitoring applied during his follow-up. Thus, it can be concluded that, in differential diagnosis of abdominal pain in adult ages, though less frequently seen than in children, gastrointestinal system foreign bodies should always be kept in mind and it should be considered that ingestion of pebbles may be one of the factors contributing to abdominal pain particularly in young adults with psychiatric problems. In such cases suspected of having foreign bodies which cannot be detected by plain films, abdominal tomography can be an alternative for diagnostic imaging.
基金This work was supported by a project (Grant No. KZ951-A1-401-07) of the Chinese Academy of Sciences.
文摘Eclogite pebbles are first discovered in late Jurassic conglomerates of the Fenghuangtai Formation from the northern foot of the Dabie Mountains, eastern China. The eclogite shows relatively strong retrograde metamor-phism. The major remnant minerals are garnet, phengite, quartz, rutile, clinozoisite, fingerprint(or worm)-form sym-plectite and pseudomorphic enclosure of coesite in garnet. End-member components of the garnet mainly made up of grossular (27.7%-37.8%), almandinc (45.5%-49.0%) and pyrope (12.3%-25.7%). End-member components of the pyrope is less than 30%, i.e. equivalent to C type eclogite. Si-cations of the phengite are 3.44-3.54 p.f.u. (taking O=11as standard). It is estimated that the pressures are 2.5-3.2 GPa, the temperatures are 600-900℃. Discovery of the eclogite pebbles in the late Jurassic conglomerates from the northern foot of the Dabie Mountains suggests that the HP-UHP metamorphic rocks of the Dabie Mountains, which were formed in Triassic, had been exposed to the surface in
文摘Recently, there has been a growing interest in gait retraining to alter the gait parameters of different populations.In these gait retraining, peak plantar pressure (PPP) was considered as an important parameter of the footbiomechanics. It has been found that high PPP correlates to the common foot deformities including pes planus/cavus. However, previous studies utilized excessive electronics in gait retraining, which is challenging toimplement daily especially when device cleaning, flexibility and portability are considered. Therefore, this studyinvestigated feasibility of a novel unpowered gait retraining for reducing high PPP. Twelve potential participantsidentified for investigation through a baseline PPP evaluation with Novel Pedar-x system. Participants received asingle session for the gait retraining with pebbles in the form of rigid spherical inserts (RSI) placed in locations ofhigh PPP inside the deformable insole. This provides tactile cues alerting the participants to alter their gait toreduce excess PPP. The PPP values were tracked in weekly follow-up sessions for 6 weeks. The results demonstrated that participants responded to RSI altering their gait to reduce PPP and maximum force by 14% and 10.5%after six weeks respectively. This study is valuable for physicians in reducing PPP when non-electronics arerequired.
基金Supported by Beijing Municipal Natural Science Foundation of China(Grant No.8252017)National Natural Science Foundation of China(Grant Nos.51608521,52178375)Beijing Urban Construction Group Co.,Ltd.
文摘To elucidate the wear mechanisms of the scraper in shield tunneling through sandy pebble strata,this study aims to achieve high efficiency and low wear during the tunneling process.We evaluate the operational parameters and tool wear characteristics of a 9-m diameter spoke-type shield machine used on the Beijing Daxing Airport Line.The analysis focuses on the wear values of the scrapers and rippers,wear of the scraper in different wear forms,and scraper wear relative to the position of the rippers obtained from the field.The study yielded the following conclusions.The wear values of scrapers on different spokes vary significantly owing to ripper protection.The wear of the scrapers can be categorized into six types:tooth chipping,local damage of teeth,wear of side teeth,wave-type of wear,wear on intermediate teeth,and flat wear,with the majority exhibiting wear on the side and intermediate teeth.The 0°spoke maintained the initial shape of the scrapers,making it more suitable for tunneling in sandy pebble strata.Based on the differences in the relative positions of the ripper and scraper,a model is proposed to determine the ripper plowing influence area.It was found that this area depends on the geological conditions of the soil;thus,the influence angle of ripper plowing in the considered sandy pebble strata is determined to be between 35°and 50°.The results obtained in this study provide a theoretical reference for optimizing scraper layouts in shield construction,even when operating under varying geological conditions.
基金supported by State Key Laboratory of Mineral Processing (No.BGRIMM-KJSKL-2022-16)China Postdoctoral Science Foundation (No.2021M700387)+1 种基金National Natural Science Foundation of China (No.G2021105015L)Ministry of Science and Technology of the People’s Republic of China (No.2022YFC2904502)。
文摘X-ray fluorescence(XRF)sensor-based ore sorting enables efficient beneficiation of heterogeneous ores,while intraparticle heterogeneity can cause significant grade detection errors,leading to misclassifications and hindering widespread technology adoption.Accurate classification models are crucial to determine if actual grade exceeds the sorting threshold using localized XRF signals.Previous studies mainly used linear regression(LR)algorithms including simple linear regression(SLR),multivariable linear regression(MLR),and multivariable linear regression with interaction(MLRI)but often fell short attaining satisfactory results.This study employed the particle swarm optimization support vector machine(PSO-SVM)algorithm for sorting porphyritic copper ore pebble.Lab-scale results showed PSO-SVM out-performed LR and raw data(RD)models and the significant interaction effects among input features was observed.Despite poor input data quality,PSO-SVM demonstrated exceptional capabilities.Lab-scale sorting achieved 93.0%accuracy,0.24%grade increase,84.94%recovery rate,57.02%discard rate,and a remarkable 39.62 yuan/t net smelter return(NSR)increase compared to no sorting.These improvements were achieved by the PSO-SVM model with optimized input combinations and highest data quality(T=10,T is XRF testing times).The unsuitability of LR methods for XRF sensor-based sorting of investigated sample is illustrated.Input element selection and mineral association analysis elucidate element importance and influence mechanisms.
基金the Scientific research and technology development project of Petro China(2021DJ5303)。
文摘Sedimentary process research is of great significance for understanding the distribution and characteristics of sediments.Through the detailed observation and measurement of the Sangyuan outcrop in Luanping Basin,this paper studies the depositional process of the hyperpycnal flow deposits,and divides their depositional process into three phases,namely,acceleration,erosion and deceleration.In the acceleration phase,hyperpycnal flow begins to enter the basin nearby,and then speeds up gradually.Deposits developed in the acceleration phase are reverse.In addition,the original deposits become unstable and are taken away by hyperpycnal flows under the eroding force.As a result,there are a lot of mixture of red mud pebbles outside the basin and gray mud pebbles within the basin.In the erosion phase,the reverse deposits are eroded and become thinner or even disappear.Therefore,no reverse grading characteristic is found in the proximal major channel that is closer to the source,but it is still preserved in the middle branch channel that is far from the source.After entering the deceleration phase,normally grading deposits appear and cover previous deposits.The final deposits in the basin are special.Some are reverse,and others are normal.They are superimposed with each other under the action of hyperpycnal flow.The analysis of the Sangyuan outcrop demonstrates the sedimentary process and distribution of hyperpycnites,and reasonably explain the sedimentary characteristics of hyperpycnites.It is helpful to the prediction of oil and gas exploration targets in gravity flow deposits.
文摘基于计算流体力学(Computational Fluid Dynamics,CFD)通用计算程序Fluent,研究了模块化熔盐冷却球床堆(Pebble Bed Advanced High Temperature Reactor,PB-AHTR)中心热通道稳态热工水力行为。利用已开发的多孔介质流固两相局域非热平衡模型计算了球床堆中的压降、冷却剂的温场分布以及固相球床的温场分布,计算并比较了不同的多孔介质阻力因子(Ergun与KTA)对通道内的冷却剂流动以及温场分布的影响,并对丧失部分冷却剂情况下通道内的冷却剂及燃料温度进行了计算分析。结果表明使用不同的阻力因子对堆芯压降计算结果和流场的分布影响较大;而冷却剂温场及固相球床温场和球心的温度分布在不同的阻力因子下的差别较小,在PB-AHTR的设计参数下堆芯产生的热量能够被有效的输出,设计具有较大的安全裕度。计算结果对于球床堆的优化设计提供了一定的参考价值。
基金supported by China Geological Survey projects (Grant Nos.1212011120836,1212011220248)China Scholarship Council (Grant No.201308360142)+2 种基金Gan-Po Excellent Talents 555 Project of Jiangxi Province (GCZ 2012-1)Research Foundation of Jiangxi Education Department (Grant No.GJJ13438)the open fund of Fundamental Science on Radioactive Geology and Exploration Technology Laboratory (Grant No.RGET1304)
文摘The Gan-Hang Belt in Southeast China is characterized by several igneous and siliciclastic basins associated with crustal extension during Late Mesozoic. The sedimentary evolution of the red basins is still poorly understood. In this study, sedimentary fades analysis and pebble counting were performed on outcrop sections of the Late Cretaceous Guifeng Group in the Yongfeng-Chongren Basin in central Jiangxi Province. Thirty-five conglomerate outcrops were chosen to measure pebble lithology, size, roundness, weathering degree and preferred orientation. Results show that gravels are mostly fine to coarse pebbles and comprise dominantly quartzites, metamorphic rocks, granitoids and sandstones. Rose diagrams based on imbricated pebbles indicate variable paleocurrent directions. Combining with typical sedimentary structures and vertical successions, we suggest that the Guifeng Group were deposited in alluvial fan, river and playa lake depositional systems. The proposed depositional model indicates that the Hekou Formation represents the start-up stage of the faulted basin, accompanied by sedimentation in alluvial fan and braided river environments. Then this basin turned into a stable expansion stage during the deposition of the Tangbian Formation. Except for minor coarse sediments at the basin margin, the other area is covered with fine-grained sediments of lake and river environments. The Lianhe Formation, however, is once again featured by conglomerates, suggesting a probable tectonic event. Therefore, the study region possibly suffered two tectonic events represented by the conglomerates of the Hekou and Lianhe formations in the context of the crustal extension in Southeast China.
