This study examined the effect of different b values on diffusion-weighted MR imaging （DWI） of human prostate by using single-shot spin echo echo planar imaging （SE-EPI） sequences, observed the normal appearances ...This study examined the effect of different b values on diffusion-weighted MR imaging （DWI） of human prostate by using single-shot spin echo echo planar imaging （SE-EPI） sequences, observed the normal appearances and measured apparent diffusion coefficient （ADC） values in anatomical regions of normal prostate. Twenty-four healthy volunteers （mean age： 32 y） were studied by using a 1.5T system with a phased array surface multicoil. Two kinds of single-shot SE-EPI sequence were used to perform DWI in the prostate in volunteers, with five b values being 0, 30, 300, 500 to 1000 s/mm2. The image quality with different imaging parameters was analyzed and the ADC values in anatomical regions of normal prostate were measured. DWI of prostate was successfully obtained in all volunteers. The images were of good quality, without artifacts containing pixels within the prostate. The contrast was good between the different anatomical regions of the prostatic gland, i.e., the peripheral zone （PZ）, which exhibited higher signal intensity, and the central gland （CG）. Signal intensity contrast was related to the magnitude of b values. The ADC values in PZ and CG were （1.27±0.22）×10-3 mm2/s and （1.01±0.17）×10-3 mm2/s,respectively. The ADC values were found to be significantly higher in PZ than in CG （P〈0.05, paired t-test）. Significant differences were found between the slice-selecting component and both the read-out and phase-encoding components of the ADC values. It is concluded that SE-EPI is a suitable DWI sequence for human prostate. The contrast between PZ and CG is good when b values are low, while the diffusion and ADC values are accurate when b values are high. ADC values are higher in PZ than in CG in normal prostate. Diffusional anisotropy is present in normal prostatic tissue.展开更多
A preliminary study of b value of rocks with two kinds of structural models has been made on the base of a new acoustic emission recording system. It shows that b value of the sample decreases obviously when the sampl...A preliminary study of b value of rocks with two kinds of structural models has been made on the base of a new acoustic emission recording system. It shows that b value of the sample decreases obviously when the sample with compressive en echelon faults changes into a tensile one after interchange occurs between stress axis σ1 and σ2. A similar experiment is observed when the sample with tensile en echelon faults changes into that with a bend fault after two segments of the en echelon fault linking up. These facts indicate that the variation of b value may con-tain the information of the regional dominant structural model. Therefore, b-value analyses could be a new method for studying regional dominant structural models.展开更多
The improved calculation method of b value is presented in tills paper. The method can enlarge the role of earthquake occurrence frequency in b value calculation and thus increase the b value variation amplitude. In t...The improved calculation method of b value is presented in tills paper. The method can enlarge the role of earthquake occurrence frequency in b value calculation and thus increase the b value variation amplitude. In this case,the combination structure variation between earthquake magnitudes and corresponding frequencies could be shown clearly. According to the calculation and analysis for limited mainshocks in the complete seismicity data of selected monitored area with assigned consistent lowest magnitude, the precursor anomaly features, quantitative indexes and the calculation formula of relative subject function of b value variation have been preliminarily worked out. The prediction in short period (from 1 to 3 months) for damage earthquakes in the monitored area mentioned above can be put forward on the basis of the results of quantitative calculation and analysis.展开更多
This paper points out that it is theoretically wrong for the traditional method to determine cumulatiove b value using linear regression and derive earthquake recurrence relation according to probability distribution ...This paper points out that it is theoretically wrong for the traditional method to determine cumulatiove b value using linear regression and derive earthquake recurrence relation according to probability distribution or density function. As a result, it always systematically overestimated b value so as to underestimate the frequencies of the part of larger earthquakes. The smaller the actual b in the research area, or the smaller the magnitude range of the data in regression, or the smaller the magnitude interval, the larger the above deviation. So for an area with lower upper bound magnitude, if only historic earthquake data are used to determine b value by regression method, the b value will be obviously overestimated and systematic deviation of seismic hazard will be arised because the lower bound magnitude of reliable data is high and the magnitude range of data is small. In this paper, it is suggested to substitude cumulative b value without upper bound magnitude for conventional cumulative b value with upper bound magnitude, and the regression method is devloped to determine b value without upper bound magnitude.展开更多
Anti-floating design of building engineering is a very important link in many engineering design links.In recent years, some cases of basement anti floating engineering failure have been exposed in the media, and the ...Anti-floating design of building engineering is a very important link in many engineering design links.In recent years, some cases of basement anti floating engineering failure have been exposed in the media, and the scene is often shocking, which also rings the alarm bell for the majority of designers. The technical standard for anti floating of Building Engineering (jgj476-2019) issued and implemented by the Ministry of housing and urban rural development on March 1, 2020 is timely and effective, which provides a powerful and reliable technical implementation standard for anti floating design, construction, monitoring and detection.The author studies and uses this standard, compares other standards and combines with the engineering practice, and finds that when the group piles in the anti floating standard are damaged as a whole, it is necessary to further discuss the calculation formula in the corresponding clauses of the standard value of the ultimate bearing capacity of a single anti floating pile.In order to ensure the safety of the design, at the same time, make the theoretical concept clear and clear, but also take into account the principle of economy, this paper discusses this problem as follows.展开更多
Objective To investigate the value of BT-H3 in expressed prostatic secretions ( EPS) in differential diagnosis of patients with inflammatory elevation of PSA in t - PSA gray zone ( 4 - 10 ng /ml) . Methods One hundred...Objective To investigate the value of BT-H3 in expressed prostatic secretions ( EPS) in differential diagnosis of patients with inflammatory elevation of PSA in t - PSA gray zone ( 4 - 10 ng /ml) . Methods One hundred and sixteen patients from ages of 19 to 80 years ( mean,40 years) were studied. In the group there展开更多
Effects of Al（Ⅲ） concentration and pH on the speciation of Al（Ⅲ） in polyaluminum chloride （PACl） solutions especially on the Al13 fraction were investigated. A series of PACl samples were prepared over the ran...Effects of Al（Ⅲ） concentration and pH on the speciation of Al（Ⅲ） in polyaluminum chloride （PACl） solutions especially on the Al13 fraction were investigated. A series of PACl samples were prepared over the range of Al（Ⅲ） concentration from 0.01 to 2.0 mol/L with the B （OH/Al ratio） value from 1.0 to 2.5 by forced hydrolysis of AICl3. The samples were characterized by ferron assay, pH and 27^Al NMR. It was shown that the Al（Ⅲ） concentration had a dramatic effect on the hydrolysis processes and the species distribution of PACl was in relate to the decrease of pH. The fraction of Al species, Alb （or Al13） decreased and Al0 increased with increase of total Al（Ⅲ） concentration. Under the condition of Al（Ⅲ） 2.0 reel/L, B = 2.5, the pH value was 2.73 and no Al13 could be detected. During diluting and aging, the species distribution evoIved. The Al13 could then be detected again and the amounts increased with time. If the diluted samples were concentrated by freeze dry at -35℃ or heating at 80℃, the pH value and Al13 content would decrease with the increased concentration. It demonstrated that the key factor for formation of Al13 in concentrated PACl was pH value.展开更多
Previous studies have shown that the active tectonic block boundaries in the Chinese mainland are the main belts and concentration areas of strong earthquakes occurring in the Chinese mainland.It is essential to carry...Previous studies have shown that the active tectonic block boundaries in the Chinese mainland are the main belts and concentration areas of strong earthquakes occurring in the Chinese mainland.It is essential to carry out follow-up analysis of strong earthquake risk of active tectonic block boundaries.In this paper,we carry out the analysis on the tendency of strong earthquakes along each active tectonic block boundary from three aspects respectively,including the evolutionary characteristics of the Load/Unload Response Ratio time series,the probability method based on the log-normal distribution function,and variation of b value.The estimation of strong earthquake criticality on each active tectonic block boundary is done based on the evolutionary characteristics of the Load/Unload Response Ratio time series,the cumulative probability and conditional probability,and the decrease of the b value.Finally,according to the results of analyses on the above three aspects,the potential strong earthquake areas in the forthcoming 5 years in the Chinese mainland are discussed.展开更多
Based on the research and the division of the active tectonic blocks and their boundaries on the Chinese mainland, the feature of the large earthquake activities on the 24 boundaries between the 6 active tectonic bloc...Based on the research and the division of the active tectonic blocks and their boundaries on the Chinese mainland, the feature of the large earthquake activities on the 24 boundaries between the 6 active tectonic block regions (grade Ⅰ) and the 22 active tectonic blocks (grade Ⅱ) are studied. The seismicity levels on the active tectonic block boundaries are discussed considering the large earthquake frequency and the released strain energy in unit distance and time. The theoretic maximal magnitude and the recurrence period of each boundary are then calculated from the G-R relation. By comparing this with the actual earthquake records, it is found that the intensities of the earthquake deduced from the seismic activity parameter (a/b) on the main active boundaries on the Chinese mainland are consistent with that of the natural earthquakes. Meanwhile, an inverse relation is found between the recurrence periods of large earthquakes and the tectonic motion rate on the boundaries. These results show that the a, b values of each boundary obtained in this paper are valuable. In addition, the present seismic activities and hazards of these boundaries are also probed into with the historical data and their elapsed time on each boundary based on the hypothesis that the large earthquakes satisfy Poisson distribution.展开更多
For several seismic statistical zones in North China, the key factors causing uncertainties in the important seismicity parameters b and v4 and the features of their uncertainties are discussed in this paper. The magn...For several seismic statistical zones in North China, the key factors causing uncertainties in the important seismicity parameters b and v4 and the features of their uncertainties are discussed in this paper. The magnitude of uncertainty is also analyzed. It can be seen that the key influencing factors are statistical period, methods of processing statistical samples, lower limit magnitude and the annual average occurrence ratio of large earthquakes. The variation ranges of b and v4 in the Tancheng-Lujiang zone are as high as 0.2 and 1. 4 respectively, which are similar to those in the Fenwei zone. They are much smaller however in the Hebei zone because of its sufficient statistical samples.展开更多
The deformation driving tendency of various single particle orbitals near the Fermi surface has been investigated with the lifetime measurements of high spin states in the non-yrast bands of ^(177)Re nucleus.For this ...The deformation driving tendency of various single particle orbitals near the Fermi surface has been investigated with the lifetime measurements of high spin states in the non-yrast bands of ^(177)Re nucleus.For this study,the ^(165)Ho(^(16)O,4n)^(177) Re reaction at a beam energy of 84 MeV was used.Lifetimes of four lowest levels in theπi13/2[660] 1/2^(+)band and four levels in the πd_(5/2)[402]5/2^(+)(α=-1/2) band were measured.The extracted transition quadrupole moments for the πi13/2intruder band showed a sharp increase with increasing level spin,indicating a significant shape transition in the nucleus.The average transitional quadrupole moment(Q_(t)),a measure of deformation,for the πi_(13/2) band was significantly larger(Q_(t)~8.7(6) eb) compared with the πd5/2(Q_(t)~6.3(5) eb) band.To interpret the observed shape changes in the two bands,the experimental transition probabilities for these bands were compared with the re sults obtained from Projected Shell Model(P SM) calculations.展开更多
Diffusion-weighted imaging (DWI) as a new technique of magnetic resonance imaging (MRI) is used to detect focal hepatic lesions. This study was designed to evaluate the significance of DWI to differentiate focal hepat...Diffusion-weighted imaging (DWI) as a new technique of magnetic resonance imaging (MRI) is used to detect focal hepatic lesions. This study was designed to evaluate the significance of DWI to differentiate focal hepatic lesions less than 3 cm in diameter by the quantitation of apparent diffusion coefficient (ADC) values. METHODS:DWI using 1.5T MRI scanner unit was performed with a spin-echo single-shot echo planar imaging (EPI) in 56 cases of small focal hepatic lesions, including hepatocellular carcinoma (11), hepatic metastatic tumor (15 ), hepatic cavernous hemangioma (14), and hepatic cyst (16).The ADC values of these lesions were calculated respectively. The ratios of the ADC values of lesion/liver in hepatocellular carcinomas and hepatic metastatic tumors were also estimated. RESULTS:The mean ADC values (mm2/s) were (0.93±0.06) ×10-3 in hepatocellular carcinomas, (1.09±0.18)×10-3 in hepatic metastatic tumors,(1.95±0.38)×10-3 in hepatic cavernous hemangiomas, and (3.18±0.33) ×10-3 in hepatic cysts. The ratios of ADC values of lesion/liver were 0.90±0.06 and 1.15±0.14 in hepatocellular carcinoma and hepatic metastatic tumors respectively, which were significantly different (P<0.05). CONCLUSION:The measurement of ADC values and the ratios of ADC values of lesion/liver are helpful in MR diagnosis and differentiation of focal hepatic lesions.展开更多
The influence of non-uniqueness in selecting statistical time ranges on seismicity parameters of b value and annual mean occurrence rate ν4 is widely analyzed and studied. The studied result states that the influence...The influence of non-uniqueness in selecting statistical time ranges on seismicity parameters of b value and annual mean occurrence rate ν4 is widely analyzed and studied. The studied result states that the influence of statistical time range on the b value is generally smaller than on the annual mean rate. Owing to the exponentially functional relation between the annual mean rate and b value, the variation of b value by varying statistical time range brings about decrease or increase in the annual mean rates of each magnitude interval with power progression law. These results will exert a synthetic effect on seismic safety evaluation results in various regions in our country.展开更多
The Mid-Niigata Prefecture Earthquake did not rupture the earth’s surface and occurred along a fault hidden well under folded terrain.In order to evaluate the seismic activity of such hidden earthquakes beneath fault...The Mid-Niigata Prefecture Earthquake did not rupture the earth’s surface and occurred along a fault hidden well under folded terrain.In order to evaluate the seismic activity of such hidden earthquakes beneath fault-related folds,a new method to analyze self-affinities is introduced.Based on this analysis,the geometry of a fold is shown to be self-affine and can be variously scaled in different directions.The size and temporal properties,b-value in Gutenberg-Richter’s law and p-value in the modified Omori’s law,express aftershock activity.Then,from the analyzed data of the folds,we estimate the bvalue and p-value of the hidden earthquake under the fault-related folds.These estimated b-values and p-values are concordant with seismologically obtained ones in the aftershock sequence of the Mid-Niigata Prefecture Earthquake.展开更多
Objective To analyze the serum keratin 18(K18)level of patients with hepatitis B virus(HBV)-related acute-on-chronic liver failure(HBV-ACLF)and its correlation with prognosis.Methods From December 2012 to October 2014...Objective To analyze the serum keratin 18(K18)level of patients with hepatitis B virus(HBV)-related acute-on-chronic liver failure(HBV-ACLF)and its correlation with prognosis.Methods From December 2012 to October 2014,120 patients who visited Fuzhou Infectious Diseases Hospital and were diagnosed with HBV-ACLF were enrolled,and 20 chronic hepatitis B(CHB)pa-展开更多
The properties of the ground and excited-state（γ-and β-bands） of ^168-178 Hf nuclei have been studied.The ratio r（I ＋2/I） and Eγ（I→I-2）/I have been calculated as a function of the spin（I） to determine the...The properties of the ground and excited-state（γ-and β-bands） of ^168-178 Hf nuclei have been studied.The ratio r（I ＋2/I） and Eγ（I→I-2）/I have been calculated as a function of the spin（I） to determine the groundstate evolution. The results indicate that these isotopes have a rotational property SU（3）. The energy levels for the ground-state, γ-and β-bands of ^168-178 Hf have been calculated using the Interacting Boson Model and Semi Empirical Formula（SEF）. The parameters of the best fit to the measured data are determined. The behavior of energy and B（E2） ratios in the ground state band are examined.展开更多
The nuclear structure of the actinide even-even thorium isotopes from A=230-234 have been investigated within the framework of the Interacting Boson Model（IBM-1）. Predictions are given for the excited state energies...The nuclear structure of the actinide even-even thorium isotopes from A=230-234 have been investigated within the framework of the Interacting Boson Model（IBM-1）. Predictions are given for the excited state energies for the ground state, β and γ-bands, the transition probabilities between these states, the rotational moment of inertia, and the energy staggering in the γ-band energies. The results of these calculations are compared with the experimental data on these isotopes.展开更多
We established a three-dimensional finite element model of the Anninghe-Zemuhe-Xiaojiang faults region using contact surfaces of different sizes to describe the spatial segmentation characteristics of the faults. Our ...We established a three-dimensional finite element model of the Anninghe-Zemuhe-Xiaojiang faults region using contact surfaces of different sizes to describe the spatial segmentation characteristics of the faults. Our model is based on constraints from GPS observations, models of the crust and upper mantle, precise earthquake locations, the tectonic stress field, the slip rate of the faults, and the rheology of the lithosphere in the Sichuan-Yunnan area. Considering the influence of strong earthquakes since A.D. 1327, we analyzed the main controlling factors of the characteristics of the strong earthquakes and also studied by numerical simulation the possible areas of future earthquake risk and their relationship with tectonic stress. The numerical results showed that the gravitational potential energy of the Qinghai-Tibet Plateau and the interaction of adjacent blocks are the main kinetic factors affecting the characteristics of the tectonic stress distribution. There appears to be some correspondence between the distribution of tectonic stress and the b value; however, we also found that some low b value locations correspond to regions of lower stress. This contradiction may be the result of some comprehensive factors, such as the release of strain energy caused by strong earthquakes.展开更多
基金supported by a grant from Key Project of Science and Technology Research of Hubei Province of China (No. 2005AA304B08).
文摘This study examined the effect of different b values on diffusion-weighted MR imaging （DWI） of human prostate by using single-shot spin echo echo planar imaging （SE-EPI） sequences, observed the normal appearances and measured apparent diffusion coefficient （ADC） values in anatomical regions of normal prostate. Twenty-four healthy volunteers （mean age： 32 y） were studied by using a 1.5T system with a phased array surface multicoil. Two kinds of single-shot SE-EPI sequence were used to perform DWI in the prostate in volunteers, with five b values being 0, 30, 300, 500 to 1000 s/mm2. The image quality with different imaging parameters was analyzed and the ADC values in anatomical regions of normal prostate were measured. DWI of prostate was successfully obtained in all volunteers. The images were of good quality, without artifacts containing pixels within the prostate. The contrast was good between the different anatomical regions of the prostatic gland, i.e., the peripheral zone （PZ）, which exhibited higher signal intensity, and the central gland （CG）. Signal intensity contrast was related to the magnitude of b values. The ADC values in PZ and CG were （1.27±0.22）×10-3 mm2/s and （1.01±0.17）×10-3 mm2/s,respectively. The ADC values were found to be significantly higher in PZ than in CG （P〈0.05, paired t-test）. Significant differences were found between the slice-selecting component and both the read-out and phase-encoding components of the ADC values. It is concluded that SE-EPI is a suitable DWI sequence for human prostate. The contrast between PZ and CG is good when b values are low, while the diffusion and ADC values are accurate when b values are high. ADC values are higher in PZ than in CG in normal prostate. Diffusional anisotropy is present in normal prostatic tissue.
基金National Natural Science Foundation of China (Grant No. 40072067) and Minister of Science and Technology of China (2004BA601B01).
文摘A preliminary study of b value of rocks with two kinds of structural models has been made on the base of a new acoustic emission recording system. It shows that b value of the sample decreases obviously when the sample with compressive en echelon faults changes into a tensile one after interchange occurs between stress axis σ1 and σ2. A similar experiment is observed when the sample with tensile en echelon faults changes into that with a bend fault after two segments of the en echelon fault linking up. These facts indicate that the variation of b value may con-tain the information of the regional dominant structural model. Therefore, b-value analyses could be a new method for studying regional dominant structural models.
文摘The improved calculation method of b value is presented in tills paper. The method can enlarge the role of earthquake occurrence frequency in b value calculation and thus increase the b value variation amplitude. In this case,the combination structure variation between earthquake magnitudes and corresponding frequencies could be shown clearly. According to the calculation and analysis for limited mainshocks in the complete seismicity data of selected monitored area with assigned consistent lowest magnitude, the precursor anomaly features, quantitative indexes and the calculation formula of relative subject function of b value variation have been preliminarily worked out. The prediction in short period (from 1 to 3 months) for damage earthquakes in the monitored area mentioned above can be put forward on the basis of the results of quantitative calculation and analysis.
文摘This paper points out that it is theoretically wrong for the traditional method to determine cumulatiove b value using linear regression and derive earthquake recurrence relation according to probability distribution or density function. As a result, it always systematically overestimated b value so as to underestimate the frequencies of the part of larger earthquakes. The smaller the actual b in the research area, or the smaller the magnitude range of the data in regression, or the smaller the magnitude interval, the larger the above deviation. So for an area with lower upper bound magnitude, if only historic earthquake data are used to determine b value by regression method, the b value will be obviously overestimated and systematic deviation of seismic hazard will be arised because the lower bound magnitude of reliable data is high and the magnitude range of data is small. In this paper, it is suggested to substitude cumulative b value without upper bound magnitude for conventional cumulative b value with upper bound magnitude, and the regression method is devloped to determine b value without upper bound magnitude.
文摘Anti-floating design of building engineering is a very important link in many engineering design links.In recent years, some cases of basement anti floating engineering failure have been exposed in the media, and the scene is often shocking, which also rings the alarm bell for the majority of designers. The technical standard for anti floating of Building Engineering (jgj476-2019) issued and implemented by the Ministry of housing and urban rural development on March 1, 2020 is timely and effective, which provides a powerful and reliable technical implementation standard for anti floating design, construction, monitoring and detection.The author studies and uses this standard, compares other standards and combines with the engineering practice, and finds that when the group piles in the anti floating standard are damaged as a whole, it is necessary to further discuss the calculation formula in the corresponding clauses of the standard value of the ultimate bearing capacity of a single anti floating pile.In order to ensure the safety of the design, at the same time, make the theoretical concept clear and clear, but also take into account the principle of economy, this paper discusses this problem as follows.
文摘Objective To investigate the value of BT-H3 in expressed prostatic secretions ( EPS) in differential diagnosis of patients with inflammatory elevation of PSA in t - PSA gray zone ( 4 - 10 ng /ml) . Methods One hundred and sixteen patients from ages of 19 to 80 years ( mean,40 years) were studied. In the group there
基金The Hi-Tech Research and Development Program (863) of China (No. 2002AA601290) and the National Natural ScienceFoundation of China (No. 20247012 50578155)
文摘Effects of Al（Ⅲ） concentration and pH on the speciation of Al（Ⅲ） in polyaluminum chloride （PACl） solutions especially on the Al13 fraction were investigated. A series of PACl samples were prepared over the range of Al（Ⅲ） concentration from 0.01 to 2.0 mol/L with the B （OH/Al ratio） value from 1.0 to 2.5 by forced hydrolysis of AICl3. The samples were characterized by ferron assay, pH and 27^Al NMR. It was shown that the Al（Ⅲ） concentration had a dramatic effect on the hydrolysis processes and the species distribution of PACl was in relate to the decrease of pH. The fraction of Al species, Alb （or Al13） decreased and Al0 increased with increase of total Al（Ⅲ） concentration. Under the condition of Al（Ⅲ） 2.0 reel/L, B = 2.5, the pH value was 2.73 and no Al13 could be detected. During diluting and aging, the species distribution evoIved. The Al13 could then be detected again and the amounts increased with time. If the diluted samples were concentrated by freeze dry at -35℃ or heating at 80℃, the pH value and Al13 content would decrease with the increased concentration. It demonstrated that the key factor for formation of Al13 in concentrated PACl was pH value.
基金sponsored by the Special Basic Scientific Research Program of Institute of Earthquake Science(02092425),China Earthquake Administration
文摘Previous studies have shown that the active tectonic block boundaries in the Chinese mainland are the main belts and concentration areas of strong earthquakes occurring in the Chinese mainland.It is essential to carry out follow-up analysis of strong earthquake risk of active tectonic block boundaries.In this paper,we carry out the analysis on the tendency of strong earthquakes along each active tectonic block boundary from three aspects respectively,including the evolutionary characteristics of the Load/Unload Response Ratio time series,the probability method based on the log-normal distribution function,and variation of b value.The estimation of strong earthquake criticality on each active tectonic block boundary is done based on the evolutionary characteristics of the Load/Unload Response Ratio time series,the cumulative probability and conditional probability,and the decrease of the b value.Finally,according to the results of analyses on the above three aspects,the potential strong earthquake areas in the forthcoming 5 years in the Chinese mainland are discussed.
基金The work was supported bythe public welfare programofthe Ministry of Science and Technology of China (2004DIA3J010)the special preparatoryresearch of national keyfun-damental research project (2002CCD01700)the Young Scientists Funds of Institute of Earthquake Science , CEA(QN200401) .
文摘Based on the research and the division of the active tectonic blocks and their boundaries on the Chinese mainland, the feature of the large earthquake activities on the 24 boundaries between the 6 active tectonic block regions (grade Ⅰ) and the 22 active tectonic blocks (grade Ⅱ) are studied. The seismicity levels on the active tectonic block boundaries are discussed considering the large earthquake frequency and the released strain energy in unit distance and time. The theoretic maximal magnitude and the recurrence period of each boundary are then calculated from the G-R relation. By comparing this with the actual earthquake records, it is found that the intensities of the earthquake deduced from the seismic activity parameter (a/b) on the main active boundaries on the Chinese mainland are consistent with that of the natural earthquakes. Meanwhile, an inverse relation is found between the recurrence periods of large earthquakes and the tectonic motion rate on the boundaries. These results show that the a, b values of each boundary obtained in this paper are valuable. In addition, the present seismic activities and hazards of these boundaries are also probed into with the historical data and their elapsed time on each boundary based on the hypothesis that the large earthquakes satisfy Poisson distribution.
基金Institute of Geophysics,China Earthquake Administration
文摘For several seismic statistical zones in North China, the key factors causing uncertainties in the important seismicity parameters b and v4 and the features of their uncertainties are discussed in this paper. The magnitude of uncertainty is also analyzed. It can be seen that the key influencing factors are statistical period, methods of processing statistical samples, lower limit magnitude and the annual average occurrence ratio of large earthquakes. The variation ranges of b and v4 in the Tancheng-Lujiang zone are as high as 0.2 and 1. 4 respectively, which are similar to those in the Fenwei zone. They are much smaller however in the Hebei zone because of its sufficient statistical samples.
基金Supported by the Science and Education Research Board (SERB) of the Department of Science and Technology, Government of India (CRG/2018/003-495)the financial assistance from the University Grants Commission (UGC), India+1 种基金the Science and Engineering Research Board (SERB), Department of Science and Technology (Govt. of India) for providing financial assistance under Project (CRG/2019/004960) to carry out a part of the present research workThe financial support provided by the Institute of Eminence (IoE), Delhi University under FRP Grant 2022-23。
文摘The deformation driving tendency of various single particle orbitals near the Fermi surface has been investigated with the lifetime measurements of high spin states in the non-yrast bands of ^(177)Re nucleus.For this study,the ^(165)Ho(^(16)O,4n)^(177) Re reaction at a beam energy of 84 MeV was used.Lifetimes of four lowest levels in theπi13/2[660] 1/2^(+)band and four levels in the πd_(5/2)[402]5/2^(+)(α=-1/2) band were measured.The extracted transition quadrupole moments for the πi13/2intruder band showed a sharp increase with increasing level spin,indicating a significant shape transition in the nucleus.The average transitional quadrupole moment(Q_(t)),a measure of deformation,for the πi_(13/2) band was significantly larger(Q_(t)~8.7(6) eb) compared with the πd5/2(Q_(t)~6.3(5) eb) band.To interpret the observed shape changes in the two bands,the experimental transition probabilities for these bands were compared with the re sults obtained from Projected Shell Model(P SM) calculations.
基金This study was supported by the Natural Science Foundation of Guangdong Province, China (No.101595 and No. 32830).
文摘Diffusion-weighted imaging (DWI) as a new technique of magnetic resonance imaging (MRI) is used to detect focal hepatic lesions. This study was designed to evaluate the significance of DWI to differentiate focal hepatic lesions less than 3 cm in diameter by the quantitation of apparent diffusion coefficient (ADC) values. METHODS:DWI using 1.5T MRI scanner unit was performed with a spin-echo single-shot echo planar imaging (EPI) in 56 cases of small focal hepatic lesions, including hepatocellular carcinoma (11), hepatic metastatic tumor (15 ), hepatic cavernous hemangioma (14), and hepatic cyst (16).The ADC values of these lesions were calculated respectively. The ratios of the ADC values of lesion/liver in hepatocellular carcinomas and hepatic metastatic tumors were also estimated. RESULTS:The mean ADC values (mm2/s) were (0.93±0.06) ×10-3 in hepatocellular carcinomas, (1.09±0.18)×10-3 in hepatic metastatic tumors,(1.95±0.38)×10-3 in hepatic cavernous hemangiomas, and (3.18±0.33) ×10-3 in hepatic cysts. The ratios of ADC values of lesion/liver were 0.90±0.06 and 1.15±0.14 in hepatocellular carcinoma and hepatic metastatic tumors respectively, which were significantly different (P<0.05). CONCLUSION:The measurement of ADC values and the ratios of ADC values of lesion/liver are helpful in MR diagnosis and differentiation of focal hepatic lesions.
基金Chinese Joint Seismological Science Foundation (100110).
文摘The influence of non-uniqueness in selecting statistical time ranges on seismicity parameters of b value and annual mean occurrence rate ν4 is widely analyzed and studied. The studied result states that the influence of statistical time range on the b value is generally smaller than on the annual mean rate. Owing to the exponentially functional relation between the annual mean rate and b value, the variation of b value by varying statistical time range brings about decrease or increase in the annual mean rates of each magnitude interval with power progression law. These results will exert a synthetic effect on seismic safety evaluation results in various regions in our country.
文摘The Mid-Niigata Prefecture Earthquake did not rupture the earth’s surface and occurred along a fault hidden well under folded terrain.In order to evaluate the seismic activity of such hidden earthquakes beneath fault-related folds,a new method to analyze self-affinities is introduced.Based on this analysis,the geometry of a fold is shown to be self-affine and can be variously scaled in different directions.The size and temporal properties,b-value in Gutenberg-Richter’s law and p-value in the modified Omori’s law,express aftershock activity.Then,from the analyzed data of the folds,we estimate the bvalue and p-value of the hidden earthquake under the fault-related folds.These estimated b-values and p-values are concordant with seismologically obtained ones in the aftershock sequence of the Mid-Niigata Prefecture Earthquake.
文摘Objective To analyze the serum keratin 18(K18)level of patients with hepatitis B virus(HBV)-related acute-on-chronic liver failure(HBV-ACLF)and its correlation with prognosis.Methods From December 2012 to October 2014,120 patients who visited Fuzhou Infectious Diseases Hospital and were diagnosed with HBV-ACLF were enrolled,and 20 chronic hepatitis B(CHB)pa-
基金the University of Mosul,College of Education for Pure Science,Department of PhysicsUniversity of Kerbala,College of Science,Department of Physics for supporting this work
文摘The properties of the ground and excited-state（γ-and β-bands） of ^168-178 Hf nuclei have been studied.The ratio r（I ＋2/I） and Eγ（I→I-2）/I have been calculated as a function of the spin（I） to determine the groundstate evolution. The results indicate that these isotopes have a rotational property SU（3）. The energy levels for the ground-state, γ-and β-bands of ^168-178 Hf have been calculated using the Interacting Boson Model and Semi Empirical Formula（SEF）. The parameters of the best fit to the measured data are determined. The behavior of energy and B（E2） ratios in the ground state band are examined.
基金the invaluable support of the College of Science at the University of Kerbala is warmly acknowledged
文摘The nuclear structure of the actinide even-even thorium isotopes from A=230-234 have been investigated within the framework of the Interacting Boson Model（IBM-1）. Predictions are given for the excited state energies for the ground state, β and γ-bands, the transition probabilities between these states, the rotational moment of inertia, and the energy staggering in the γ-band energies. The results of these calculations are compared with the experimental data on these isotopes.
基金supported by the National Science and Technology Program(Grant No.2012BAK15B01)China National Special Fund for Earthquake Scientific Research in Public Interest(Grant Nos.201008001 and 201308011)+1 种基金the"Basic Science Research Plan"of the Institute of Earthquake ScienceChina Earthquake Administration(Grant No.DQJB12C08)
文摘We established a three-dimensional finite element model of the Anninghe-Zemuhe-Xiaojiang faults region using contact surfaces of different sizes to describe the spatial segmentation characteristics of the faults. Our model is based on constraints from GPS observations, models of the crust and upper mantle, precise earthquake locations, the tectonic stress field, the slip rate of the faults, and the rheology of the lithosphere in the Sichuan-Yunnan area. Considering the influence of strong earthquakes since A.D. 1327, we analyzed the main controlling factors of the characteristics of the strong earthquakes and also studied by numerical simulation the possible areas of future earthquake risk and their relationship with tectonic stress. The numerical results showed that the gravitational potential energy of the Qinghai-Tibet Plateau and the interaction of adjacent blocks are the main kinetic factors affecting the characteristics of the tectonic stress distribution. There appears to be some correspondence between the distribution of tectonic stress and the b value; however, we also found that some low b value locations correspond to regions of lower stress. This contradiction may be the result of some comprehensive factors, such as the release of strain energy caused by strong earthquakes.
