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The thermo-electric effect of magnetite and the mechanism of geo-electric abnormalities during earthquakes

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Geoscience Frontiers 2010年第1期1卷 99-104页

作者： junfeng shen Xuhui shen Qian Liu Na Ying State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences 29 Xueyuan RoadBeijing 100083 China Institute of Earthquake Science China Earthquake Administration 63 Fuxin Road Beijing 100036 China

The thermo-electric coefficients of twenty-six magnetite samples, formed either by magmatism or metamorphism, were tested by the thermo-electric instrument BHET -06. Results showed that the coef- ficient is of a constant value of about -0.05 mV/℃. It is emphasized that because every magnetite grain was tested randomly, the coefficient is independent of the crystallographic direction. This fact means the thermal voltage generated from a single magnetite crystal can be accumulated, and as a result a new thermo-electric field can arise when a gradient thermal field exists and is active within the earth＇s crust. Because magnetite is widespread in the earth＇s crust （generally appearing more in the middle-lower crust）, there is more-thanrandom probability that the additional thermo-electric field can be generated when certain thermal conditions are fulfilled. We, therefore, used the thermo-electric effect of magnetite to study the mechanism responsible for the presence of abnormal geo-electric fields during earthquake formation and occurrence, because gradient thermal fields always exist before earthquakes. The possible presence of additional thermo-electric fields was calculated under theoretical seismological conditions, using the following calculation formula：E= - 0.159（σ×△T×Ф×ρ2×[[（h^2 - 2x^2）cos α ＋ 3hxsin α]/ρ1 （h^2 ＋x^2）^5/2）. In the above formula, σ is thermo-electric coefficient of magnetite, △T is the temperature difference acting on it, Ф is a sectional area on a block of magnetite vertically perpendicular to the direction of the thermal current, ρ1 and ρ2 are the respective resistivities of magnetite and the crust, and h, α, and x, respectively, h is the depth of embedded magnetite block. α means the angle created by the horizontal line and ligature of the two poles of magnetite block, and x is the distance from observation point to projective center point of the magnetite block on earth surface. According to simulations calculated with this formula, additiona

关键词： Magnetite Thermo-electric Earthquake Abnormal geo-electricity

Antiglycating effects of citrus flavonoids and associated mechanisms

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Food Science and Human Wellness 2024年第5期13卷 2363-2372页

作者： Yunli Xiao junfeng shen Jianfeng Zhan Limin Guo Chi-Tang Ho Shiming Li College of Biology and Agricultural Resources Huanggang Normal UniversityHuanggang 438000China Institute of Agro-Products Storage and Processing Xinjiang Academy of Agricultural SciencesUrumqi 830091China Department of Food Science Rutgers UniversityNew Brunswick 08901USA

Glycation of proteins and DNA forms advanced glycation end products(AGEs)causing cell and tissue dysfunction and subsequent various chronic diseases,in particular,metabolic and age-related *** AGE inhibition includes scavengers of reactive carbonyl species(RCS)such as methylglyoxal(MG),glyoxalase-1 enhancers,Nrf2/ARE pathway activators,AGE/RAGE formation inhibitors and other antiglycatng *** flavonoids have demonstrated antioxidant and anti-inflammatory effects and are also found to be effective antiglycating ***,we reviewed the up to date progress of the antiglycation effects of citrus flavonoids and associated *** citrus flavonoids,hesperedin and its aglycone,hesperetin,inhibited glycation by scavenging MG forming mono-or di-flavonoid adducts with MG,enhanced the activity of glyoxase-1,activated Akt/Nrf2 signal pathway while inhibiting AGE/RAGE/NF-κB pathway,reduced the formation of Nε-(carboxylmethyl)lysine(CML)and pentosidine,inhibited aldol reductase activity and decreased the levels of *** antiglycating activity and mechanisms of other flavonoids was also summarized in this *** conclusion,citrus flavonoids possess effective antiglycating activity via different mechanisms,yet there are many challenging questions remaining to be studied in the near future such as in vivo testing and human study of citrus flavonoids for efficacy,effectiveness and adverse effects of citrus flavonoids as a functional food in managing high levels of AGEs and controlling AGE-induced chronic diseases,diabetic complications in particular.

关键词： Citrus flavonoids Hesperedin Advanced glycation end products Antiglycation Diabetic complication

Thermoelectric characteristics of semiconductor minerals in earth's deep crust and their seismogenic significance

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Geoscience Frontiers 2022年第2期13卷 159-164页

作者： Shuhao Wang junfeng shen M.Santosh Yuanyuan Li Cheng-Xue Yang Liangkun Ma School of Earth Sciences and Resources China University of GeosciencesBeijing 100083China Department of Earth Science University of AdelaideAdelaideSA 5005Australia

Geo-electric anomalies are generated during the process of stress accumulation and release associated with ***,the mechanism of these anomalies remains *** on the analysis of thermoelectric characteristics of semiconductor minerals of the earth’s deep crust such as graphite,ferrosilicon alloy,magnetite etc.,we perform finite element analysis to evaluate the principles governing the thermoelectric power generated by minerals and *** results show that graphite,ferrosilicon alloy and magnetite all exhibit Seebeck effect and can be *** the thermo-electric field can be enhanced with the activation temperature increases,the content of thermoelectric minerals increases,the size of aggregates increases,and the spacing of thermoelectric minerals grains *** processes would generate a similar thermal *** natural semiconductor minerals in this thermal field show a thermoelectric effect,forming a thermoelectric field that interferes with the background electric *** study indicates that thermoelectric effect may have an important influence on the formation of geoelectric field.

关键词： Natural semiconductor minerals Seebeck effects Geoelectric anomalies Earthquakes Deep crust

Study on Swell Pressure Stress of Bentonite in Geosynthetic Clay Liners

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Acta Geologica Sinica(English Edition) 2006年第5期80卷 763-769页

作者： shen junfeng LI shengrong HE Shaohui ZHANG Guangshan TONG Jinggui YAN Bokun State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Beijing 100083 Key Laboratory of Lithospheric Tectonics and Exploration Ministry of Education China University of Geosciences Beijing 100083 School of Civil Engineering and Architecture Beijing Jiaotong University Beijing 100044

The geosynthetic clay liner （GCL） is a kind of waterproofing material used widely in engineering. The waterproof mechanism is understood in terms of bentonite particles becoming water-obstruct colloid layers after they sorb water and swell. The swell pressure stress, however, has not been determined directly till now. In our experiment, swell pressure stress of the GCL under saturated water-sorbing condition was measured directly using a custom-made instrument. The results show that （1） the instrument designed by the authors performs satisfactorily and the test results are reproducible; and （2） the trend line of swell pressure stress variation with time can be divided into three segments. The first segment is characterized by a quick increase of the swell force in the first 0-50 hours. The swell pressure stress increases by 7.00×10^-4-1.00×10^-3 MPa/h. The second segment shows a slow increase of the swell pressure stress from the 50th to 1730th hour. The swell force increases by 7.54×10^-6-2.02×10^-5 MPa/h. The third segment is characterized by a little variation in swell pressure stress after 1730 hours. In this segment, the average value of the swell pressure stress measurements is 0.0719 MPa and the maximum value is 0.0729 MPa. It is suggested that the swell pressure stress is mainly raised by water entering pores among montmorillonite particles and interstitial layers in individual montmorillonite crystals, leading to an increase of volume.

关键词： geosynthetic clay liners waterproof swell pressure stress test

Dating Fault Activity Based on Surface Texture of Quartz Grains from the Bailong River Fault

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Acta Geologica Sinica(English Edition) 2014年第4期88卷 1131-1144页

作者： shen junfeng YANG Weimin LIU Ting HUANG Xiao ZHENG Weijie YU Lei WANG Guoqiang School of Earth Science and Resources China University of Geosciences Institute of Geomechanics Chinese Academy of Geological Sciences

Much important information referring to fault motion （e.g., fault activities period, intensity, frequency, and even dynamic background） can be revealed by resolving fault gouge, which is the result of fault motion while extruding or grinding. The field investigation encompassed sample collecting from the Bailong River fault system of the western segment of the Qinling Orogenic Belt （QOB）; 44 samples of fault gouges were collected for quartz micro-morphology analysis. These samples were analyzed using field emission scanning electron microscopy. In addition, 14 samples were tested for thermo-luminescence dating. The results showed that most of the surface textures of quartz grains are characterized by fish scale, moss-like texture, and stalactite. However, a small amount of orange peel-like fractures and worm-hole-like shaped surface texture were observed. Moreover, a few typical conchoids or subconchoidal fractures in quartz grains can be seen. This implies that the Bailong River Fault was active repeatedly during the Quaternary period, but the main motion period is the Pleistocene. The 14 thermo-luminescence dating values showed two age groups： 343.29-184.06 ka and 92.18-13.87 ka. These study data reveal that fault movement started during the Pliocene, occurred frequently in the early-middle period of the Pleistocene, and the peak frequency of the motion was reached in the early Pleistocene. The fault motions were stopped terminated in the early Holocene. The results are significant for the natural disaster risk evaluation in the western segment of the QOB.

关键词： fault gouge surface texture of quartz thermo-luminescence dating Pleistocene BailongRiver Fault

Geochemistry of Pyrite from the Gangcha Gold Deposit, West Qinling Orogen, China: Implications for Ore Genesis

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Acta Geologica Sinica(English Edition) 2017年第6期91卷 2164-2179页

作者： NIE Xiao shen junfeng LIU Haiming DU Baisong WANG Shuhao LI Jie XU Liwei WANG Ran School of Earth Sciences and Resources China University of Geosciences Département de géologie et de génie géologique Université Laval Inner Mongolia Ninth Geology Mineral Exploration and Development Co. Ltd Jinyou Geological Exploring Co. Ltd The Gold of CAPF

The Gangcha gold deposit was discovered in 2011 in the Xiahe-Hezuo region, West Qinling Orogen, China. Five types of pyrite have been identified in the ore according to the detailed mineral paragenetic studies. Geochemical data are presented for type I pyrite （pyl） rim-core zonation and for the different types of pyrite based on in-situ laser ablation inductively coupled plasma mass spectrometry （LA-ICP-MS） and electron probe microanalysis （EPMA）. The results show that pyrites are characterized with heterogeneous Au concentrations, which indicate that Au occurs mainly as micro- or nano-particle native inclusions. Time-resolved depth profiles demonstrate that As, Co and Ni occur as solid solutions in pyrite, whereas Cu, Pb, Zn and Ag occur mainly as inclusions. Trace element concentrations differ between rims and cores in pyl, and the differences also exist within different pyrite types. These differences indicate complex chemical evolution of the ore-forming fluids, and the overall geology, geochronology, and stable isotope and pyrite data suggest that the ore-forming fluids were closely linked to magmatic activity during the Triassic Period in West Qinling orogenic belt.

关键词： pyrite geochemistry Gangcha gold deposit West Qinling Qrogen

Structure variety and its effects on biological activity of tea polysaccharides

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Food Science and Human Wellness 2022年第3期11卷 587-597页

作者： Ting Hu Peng Wu Jianfeng Zhan Weixin Wang junfeng shen Meiyan Wang Chi-Tang Ho Shiming Li Hubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive Utilization Huanggang Normal UniversityHuanggang 438000China School of Biotechnology and Food Science Tianjin University of CommerceTianjin 300134China Department of Food Science Rutgers UniversityNJ 08901USA

Tea polysaccharides(TPSs),one of the major bioactive ingredients in tea,have been widely studied due to their variety of biological activities,including antioxidant,cancer prevention,hypoglycemia,anti-fatigue,anti-coagulant,anti-obesity and immunomodulatory *** biological effectiveness of TPSs has direct relation with their structures such as monosaccharide composition,molecular weight,glycosidic linkages,conformation and others,which can be influenced by tea materials,processing methods,extraction and purification procedures among *** to the study of tea polyphenols,the exploration of TPSs in structural elucidation and biofunctionality is very *** several factors affecting the structural change of TPSs have been studied and ***,the variation of some TPS biological activity brought by the change of TPS structures has been evaluated and preliminary correlation of structure activity relationship of TPSs has been ***,this review aims to serve as a summary research report regarding the influencing factors on TPSs structures and consequential effects on the biological activities of *** hope to provide updated information and systematic references for future study and functional food development of TPSs.

关键词： Tea polysaccharides Structure variety Bioactivities Relationship Influencing factors

The earthquake-related disturbances in ionosphere and project of the first China seismo-electromagnetic satellite

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Earthquake Science 2011年第6期24卷 639-650页

作者： Xuhui shen Xuemin Zhang Lanwei Wang Huaran Chen Yun Wu Shigeng Yuan junfeng shen Shufan Zhao Jiadong Qian Jianhai Ding Institute of Earthquake Science China Earthquake Administration Beijing 100036 China Institute of Crustal Dynamics~ China Earthquake Administration Beijing 100085 China Institute of Geophysics China Earthquake Administration Beijing 100081 China Earthquake Administration of Hubei Province Wuhan 430071 China DFH Satellite Co. Ltd. Beijing 100094 China State Key Laboratory of Geological Processes and Mineral Resources Chinese University of Geosciences Beijing 100029 China

Based on the case studies and statistical analysis of earthquake-related ionospheric disturbances mainly from DEMETER satellite, ground-based GPS and ionosounding data, this paper summarizes the statisw tical characteristics of earthquake-related ionospheric disturbances, including electromagnetic emissions, plasma perturbations and variation of energetic particle flux. According to the main results done by Chinese scientists, fusing with the existed study from global researches, seismo-ionospheric disturbances usually occurred a few days or hours before earthquake occurrence. Paralleling to these case studies, lithosphere-atmosphere-ionosphere （LAI） coupling mechanisms are checked and optimized. A thermo-electric model was proposed to explain the seismo-electromagnetic effects before earthquakes. A propagation model was put forward to explain the electromagnetic waves into the ionosphere. According to the requirement of earthquake prediction research, China seismo-electromagnetic satellite, the first space-based platform of Chinese earthquake stereoscopic observation system, is proposed and planned to launch at about the end of 2014. It focuses on checking the LAI model and distinguishing earthquake-related ionospheric disturbance. The preliminary design for the satellite will adopt CAST-2000 platform with eight payloads onboard. It is believed that the satellite will work together with the ground monitoring network to improve the capability to capture seismo-electromagnetic information, which is beneficial for earthquake monitoring and prediction researches.

关键词： seismo-ionospheric coupling earthquake-related ionospheric disturbance China seismoelectromagnetic satellite lithosphere-atmosphere-ionosphere coupling model

Paleoearthquake Studies along the Nalinlaka Fault of the Late Pleistocene in Lhasa,Tibet

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Earthquake Research in China 2010年第4期24卷 467-477页

作者： Liu Jing Guan Peng shen Xuhui Xu Yueren shen junfeng Jing Feng Hong Shunying Institute of Earthquake Science China Earthquake Administratin Beijing 100036 China Hebei Dadi Building Construction Engineering Co. Ltd. Beijing 100027 China China University of Geosciences Beijing 100083 China

As the most import fault of the Late Pleistocene in the Lhasa area,the Nalinlaka fault is a left-lateral thrust fault,striking NWW,dipping SSW with a high dip angle,and extending over *** to studies on the latest strata on the Nalinlaka fault zone,this fault zone has been obviously active since the Late Pleistocene and the movement left behind some geomorphologic phenomena on the earth's surface,especially at the sites of the gully west of Cijiaolin and around Xiecun *** example,some rivers,ridges and terraces are displaced,forming beheaded gullies and fault *** horizontal displacements since the Late Pleistocene at the above two places are 54m ～ 87m,20m ～ 67m,*** on studies on the 4 trenches along the fault using the progressive constraining method,we conclude that there might have been 5 paleoearthquake events along the Nalinlaka fault since 70ka B.P.,the ages of each paleoearthquake are 68.53,54.40,< 41.23,21.96,9.86ka B.P.,and the average recurrence interval is *** of the limits of trenches and earthquake events exposed by each trench,no single trench completely revealed all 5 *** may therefore be some errors in determining the upper and lower limits of some events in this article.

关键词： Lhasa Active fault Paleoearthquake