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Acute effects of static stretching on peak and end-range hamstring-to-quadriceps functional ratios 被引量:3
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作者 Ufuk Sekir Ramiz Arabaci Bedrettin Akova 《World Journal of Orthopedics》 2015年第9期719-726,共8页
AIM: To evaluate if static stretching influences peak and end-range functional hamstring-to-quadriceps(H/Q) strength ratios in elite women athletes. METHODS: Eleven healthy female athletes in an elite competitive leve... AIM: To evaluate if static stretching influences peak and end-range functional hamstring-to-quadriceps(H/Q) strength ratios in elite women athletes. METHODS: Eleven healthy female athletes in an elite competitive level participated to the study. All the participants fulfilled the static stretching or non-stretching(control) intervention protocol in a randomized design on different days. Two static unassisted stretching exercises, one in standing and one in sitting position, were used to stretch both the hamstring and quadriceps muscles during these protocols. The total time for the static stretching was 6 ± 1 min. The isokinetic peak torque measurements for the hamstring and quadriceps muscles in eccentric and concentric modes and the calculations for the functional H/Q strength ratios at angular velocities of 60°/s and 180°/s were made before(pre) and after(post) the control or stretching intervention. The strength measurements and functional strength ratio calculations were based during the entire- and end-range of knee extension.RESULTS: The pre-test scores for quadriceps and hamstring peak torque and end range values were not significantly different between the groups(P > 0.05). Subsequently, although the control group did notexhibit significant changes in quadriceps and hamstring muscle strength(P > 0.05), static stretching decreased eccentric and concentric quadriceps muscle strength at both the 60°/s and 180°/s test speeds(P < 0.01). Similarly, static stretching also decreased eccentric and concentric hamstring muscle strength at both the 60°/s and 180°/s test speeds(P < 0.01). On the other hand, when the functional H/Q strength ratios were taken into consideration, the pre-intervention values were not significant different between the groups both during the entire and end range of knee extension(P > 0.05). Furthermore, the functional H/Q strength ratios exhibited no significant alterations during the entire and end ranges of knee extension both in the static stretching or the control intervention(P > 0.05). CONCLUSION: According to our results, static stretching routine does not influence functional H/Q ratio. Athletes can confidently perform static stretching during their warm-up routines. 展开更多
关键词 Elite women athletes ECCENTRIC CONCENTRIC Static stretching functional hamstring-to-quadriceps ratio Muscle strength
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Second to fourth digit ratio: a predictor of adult lung function 被引量:3
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作者 I-Nae Park Ho-Kee Yum +2 位作者 Sang Chul Lee Jin Kyu Oh Tae Beom Kim 《Asian Journal of Andrology》 SCIE CAS CSCD 2014年第1期140-145,共6页
Sex and sex hormones play a major role in lung physiology. It has been proposed that the ratio of the second to fourth digits (digit ratio) is correlated with fetal sex hormones. We therefore hypothesized that digit... Sex and sex hormones play a major role in lung physiology. It has been proposed that the ratio of the second to fourth digits (digit ratio) is correlated with fetal sex hormones. We therefore hypothesized that digit ratio might help predict lung function. We investigated the relationship between digit ratio and pulmonary function test (PFT) findings. A total of 245 South Korean patients (162 male, 83 female) aged from 34 to 90 years who were hospitalized for urological surgery were prospectively enrolled. Before administering the PFTs, the lengths of the second and fourth digits of the right hand were measured by a single investigator using a digital Vernier caliper. In males (n = 162), univariate and multivariate analysis using linear regression models showed that digit ratio was a significant predictive factor of forced vital capacity (FVC) and forced expiratory volume in I second (FEV1) (FVC: r = 0.156, P = 0.047; FEVI: r = 0.160, P = 0.042). In male ever-smokers (n = 69), lung functions (FVC and FEV1) were correlated with smoking exposure rather than digit ratio. In female never-smokers (n = 83), lung functions (FEV1 and FEVI/FVC ratio) were positively correlated with digit ratio on univariate analysis (FEVI: r = 0.242, P = 0.027; FEVI/FVC ratio: r = 0.245, P = 0.026). Patients with lower digit ratios tend to have decreased lung function. These results suggest that digit ratio is a predictor of airway function. 展开更多
关键词 airway function digit ratio sex hormone
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Features on N/P ratio of plants with different functional groups between two types of steppe in semi-arid area
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作者 YueDan Zhao XingDong He +4 位作者 Lei Chen XinFeng Ding MengQi Li PingYi Xu YuBao Gao 《Research in Cold and Arid Regions》 CSCD 2019年第5期371-381,共11页
The differences in nitrogen/phosphorus(N/P)ratios of different functional groups in ecology are more helpful in explaining species competition and community dynamics.Based on the functional groups of plant growth type... The differences in nitrogen/phosphorus(N/P)ratios of different functional groups in ecology are more helpful in explaining species competition and community dynamics.Based on the functional groups of plant growth type,carbon metabolism pathway,root type and phylogenetic type,we analyzed characteristics of leaf N/P ratios of 77 species in Sanggendalai(typical grassland zone)of Zhenglan Banner,Inner Mongolia,China and 91 species in the Habahu National Nature Reserve(desertified grassland zone)in Yanchi County of Ningxia,China.The results show that the N/P ratio(16.91)of C3 plants in the desertified steppe was significantly larger than that(12.72)in the typical steppe,but there was no significant difference between the N/P ratios of C4 plants in the two zones.There was no significant difference in N/P ratios between C3 plants and C4 plants in the same zone.Similarly,the N/P ratio(16.60)of dicotyledons in desertified steppe were significantly higher than that(12.98)in typical steppe,while differences in N/P ratios between monocotyledonous plants of the two zones was not significant,and there existed no significant difference in N/P ratios between dicotyledonous and monocotyledonous plants in the same zone.The N/P ratio had significant difference between gramineous and non-gramineous plants in the typical steppe but not in the desertified steppe,but there existed no significant difference in N/P ratios among different root types of perennial herbaceous plants in the same type of steppe or between two types of steppe.Thus,different features on the N/P ratios of C3 plants and dicotyledonous plants between typical steppe and desertified steppe may lead to different growth status of plants,and the N/P ratio stoichiometric of the same plant functional group may be a foundation of the changes of a plant community. 展开更多
关键词 SEMI-ARID region PLANT N/P ratio PLANT functional GROUPS desertified STEPPE TYPICAL STEPPE
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Reduced Partition Function Ratio in the Frequency Complex Plane: A Mathematical Approach
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作者 Jie Yuan 《Open Journal of Geology》 2014年第12期654-664,共11页
This paper gives a mathematical approach to calculate the fractionation factor of isotopes in a general cluster (also known as?super-molecule), which composes of necessary chemical effect within three bonds outside th... This paper gives a mathematical approach to calculate the fractionation factor of isotopes in a general cluster (also known as?super-molecule), which composes of necessary chemical effect within three bonds outside the interested atom(s). The cluster might have imaginary frequencies after being optimized in quantum softwares. The approach includes the contribution of the difference, which is resulted from the substitution of heavy and light isotopes in the cluster, of vibrations of imaginary frequencies to give precise prediction of isotope fractionation factor. We call the new mathematical approximation “reduced partition function ratio in the frequency complex plane (RPFRC)”. If there is no imaginary frequency for a cluster, RPFRC?is simplified to be Urey (1947) or Bigeleisen and Mayer (1947) formula. Final results of this new algorithm are in good agreement with those in earlier studies. 展开更多
关键词 ISOTOPE FRACTIONATION Cluster REDUCED PARTITION function ratio FREQUENCY Complex Plane
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Pressure-Controlled Inverse Ratio Ventilation during General Anesthesia for Open Abdominal Surgery Improves Postoperative Pulmonary Function 被引量:3
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作者 Xiuqin Wang Peimin Wang +2 位作者 Kaiguo Wang Tao Jiang Zan Xu 《Journal of Biomedical Science and Engineering》 2016年第1期17-24,共8页
Background: Studies have shown that pressure-controlled ventilation improves alveolar gas distribution. And inverse ratio ventilation has advantages of improving oxygenation in acute respiratory distress syndrome (ARD... Background: Studies have shown that pressure-controlled ventilation improves alveolar gas distribution. And inverse ratio ventilation has advantages of improving oxygenation in acute respiratory distress syndrome (ARDS) patients. However, the effects that pressure-controlled inverse ration ventilation in patients undergoes endotracheal intubation general anesthesia have not been assessed. Objective: To investigate whether pressure-controlled inverse ratio ventilation (PIV) would improve ventilatory and oxygenation parameters as well as lung function compared to conventional ventilation in patients undergoing open abdominal surgery. Interventions: In the conventional ventilation (CV) group, the ventilation strategy involved zero end-expiratory pressure and volume-controlled ventilation. In the pressure-controlled inverse ratio ventilation (PIV) group, the strategy involved P high starting at 7 cm H<sub>2</sub>O, P low starting at 4 cm H<sub>2</sub>O, T high at 4 s, T low at 2 s, and an inspiratory-to-expiratory time ratio of 2:1. The ΔP value was adjusted according to VT. Pressure levels were increased by 2 cm H<sub>2</sub>O until a maximal V<sub>T</sub> was observed. Inspired oxygen fraction (FIO<sub>2</sub>) was 1.0 and tidal volume (V<sub>T</sub>) was 6 mL/kg in both groups. Main Outcome Measures: The primary outcome is pulmonary function tests. Hemodynamic, ventilatory and oxygenation parameters were measured;visual analog scale (VAS) scores, and nausea and vomiting scores were also measured. Results: The PIV group tolerated pressure-controlled inverse ratio ventilation without significant hemodynamic instability. Mean airway pressure and static compliance were significantly higher in the PIV group than those in CV group (P P 2 h was well tolerated and improved respiratory compliance and lung function on the first postoperative day. 展开更多
关键词 Inverse ratio Ventilation Conventional Ventilation General Anesthesia Lung function
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Stepwise joint inversion of surface wave dispersion,Rayleigh wave ZH ratio,and receiver function data for 1D crustal shear wave velocity structure 被引量:9
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作者 Ping Zhang Huajian Yao 《Earthquake Science》 CSCD 2017年第5期229-238,共10页
Accurate determination of seismic velocity of the crust is important for understanding regional tectonics and crustal evolution of the Earth. We propose a stepwise joint linearized inversion method using surface wave ... Accurate determination of seismic velocity of the crust is important for understanding regional tectonics and crustal evolution of the Earth. We propose a stepwise joint linearized inversion method using surface wave dispersion, Rayleigh wave ZH ratio (i.e., ellipticity), and receiver function data to better resolve 1D crustal shear wave velocity (Vs) structure. Surface wave dispersion and Rayleigh wave ZH ratio data are more sensitive to absolute variations of shear wave speed at depths, but their sensi- tivity kernels to shear wave speeds are different and complimentary. However, receiver function data are more sensitive to sharp velocity contrast (e.g., due to the existence of crustal interfaces) and Vp/Vs ratios. The stepwise inversion method takes advantages of the complementary sensitivities of each dataset to better constrain the Vs model in the crust. We firstly invert surface wave dispersion and ZH ratio data to obtain a 1D smooth absolute vs model and then incorporate receiver function data in the joint inver- sion to obtain a finer Vs model with better constraints on interface structures. Through synthetic tests, Monte Carlo error analyses, and application to real data, we demonstrate that the proposed joint inversion method can resolve robust crustal Vs structures and with little initial model dependency. 展开更多
关键词 Joint inversion Receiver function Surfacewave dispersion Rayleigh wave ZH ratio· Shearwave velocity
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Study of crustal thickness and poisson's ratio of the south of Erenhot area by teleseismic receiver function
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作者 Lei Jiang Yonghong Duan +2 位作者 Yanna Zhao Yong Qiu Cheng Li 《Earthquake Science》 CSCD 2018年第4期215-223,共9页
The Xing’an Mongolian Orogenic Belt(XMOB) and the northern margin of North China Craton(NCC) have undergone multistage tectonic superimposition and the tectonic evolution is extremely complicated. We collect the tele... The Xing’an Mongolian Orogenic Belt(XMOB) and the northern margin of North China Craton(NCC) have undergone multistage tectonic superimposition and the tectonic evolution is extremely complicated. We collect the teleseismic data of 44 temporary broadband seismic stations deployed in the XMOB and the northern margin of NCC to calculate the P wave receiver functions. The crustal thickness and average crustal ratio as well as the Poisson’s ratios beneath 33 stations are estimated using the H-κ stacking method. The results show:(1) the crustal thickness of the study area ranges from 38.7 to 42.7 km, with an average thickness of 41.2 km. There is a great difference in crustal thickness on both sides of Solonker suture zone. The characteristics of crustal thickness support the geodynamic model that the Paleo-Asian Ocean subducted and closed at the Solonker suture zone.(2) The Poisson’s ratios in the study area are low, ranging from 0.215 to 0.277, with an average value of 0.243, suggesting that the rock composition of the area is dominated by felsic-acid rocks.(3) There exists a negative correlation between the Poisson’s ratio and the crustal thickness. Combined with the lower values of Poisson’s ratio, we speculate that the delamination is the major mechanism in crustal extension and thinning in the study area. 展开更多
关键词 Xing'an mongolia orogenic belt northern margin of North China Craton receiver function crustal thickness poisson's ratio
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腾冲火山壳幔过渡带分析及岩浆上涌通道初探
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作者 范心甜 危自根 +4 位作者 谢军 程智伟 凌媛 李雪垒 刘益炜 《地震研究》 北大核心 2025年第1期41-48,共8页
壳幔过渡带是地壳与地幔物质和能量的交换场所,其结构特征与该区的深部过程和构造演化密切相关。提取腾冲火山区31个地震台站下方的接收函数H-κ叠加获得的地壳厚度随频率变化特征和接收函数的Ps/P、PpPs/P振幅比,发现盈江断裂北部的黑... 壳幔过渡带是地壳与地幔物质和能量的交换场所,其结构特征与该区的深部过程和构造演化密切相关。提取腾冲火山区31个地震台站下方的接收函数H-κ叠加获得的地壳厚度随频率变化特征和接收函数的Ps/P、PpPs/P振幅比,发现盈江断裂北部的黑空山-燃灯寺和南侧沙坝台区域具有比周边区域更低的振幅比,约有2 km地壳厚度差异。将该观测结果与前人获得的这两个区域相对薄的地壳厚度与高的V_(P)/V_(S)比值相结合,表明黑空山-燃灯寺和沙坝台区域具有厚的壳幔过渡带,推测其是地幔物质涌入地壳的通道。结合前人获得的该区上、中、下地壳都存在大片低速体的特征,推测来自地幔的岩浆很可能沿着腾冲火山区黑空山-燃灯寺和沙坝台这两个区域上涌到地壳,并依次在下、中和上地壳富集和横向展布,最终沿多个通道喷出地表。 展开更多
关键词 腾冲火山 接收函数 振幅比 地壳厚度 壳幔过渡带 地幔上涌通道
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Increased international normalized ratio level in hepatocellular carcinoma patients with diabetes mellitus 被引量:6
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作者 Hui Zhang Chun Gao +1 位作者 Long Fang Shu-Kun Yao 《World Journal of Gastroenterology》 SCIE CAS 2013年第15期2395-2403,共9页
AIM: To determine the association of diabetes mellitus (DM) and international normalized ratio (INR) level in hepatocellular carcinoma (HCC) patients. METHODS: Our present study included 375 HCC patients who were trea... AIM: To determine the association of diabetes mellitus (DM) and international normalized ratio (INR) level in hepatocellular carcinoma (HCC) patients. METHODS: Our present study included 375 HCC patients who were treated at the China-Japan Friendship Hospital, Ministry of Health (Beijing, China), in the period from January 2003 to April 2012, and with a hospital discharge diagnosis of HCC. The demographic, clinical, laboratory, metabolic and instrumental features were analyzed. χ2 test, Student's t test and Mann-Whitney U test were used to compare the differences between HCC patients with and without DM. Unconditional multivariable logistic regression analysis was used to determine the association of DM and INR level in HCC patients. A sub-group analysis was performed to assess the effect of liver cirrhosis or hepatitis B virus (HBV) infection on the results. The Pearson correlation test was used to determine the relationship between INR level and fasting glucose. In addition, association between diabetes duration, and diabetes treatment and INR level was determined considering the potentially different effects. RESULTS: Of the total, 63 (16.8%) patients were diabetic (diabetic group) and 312 (83.2%) patients were diagnosed without diabetes (non-diabetic group). Their mean age was 56.4 ± 11.0 years and 312 (83.2%) patients were male. Compared with patients without DM, the HCC patients with diabetes were older (59.5 ± 10.3 vs 55.8 ± 11.1, P=0.015), had a lower incidence of HBV infection (79.4% vs 89.1%, P=0.033), had increased levels of systolic blood pressure (SBP) (133 ± 17 vs 129 ± 16 mmHg, P=0.048) and INR (1.31 ± 0.44 vs 1.18 ± 0.21, P=0.001), had lower values of hemoglobin (124.4 ± 23.9 vs 134.2 ± 23.4, P=0.003) and had a platelet count (median/interquartile-range: 113/64-157 vs 139/89-192, P=0.020). There was no statistically significant difference in the percentages of males, overweight or obesity, drinking, smoking, cirrhosis and Child classification. After controlling for the confounding effects of age, systolic blood pressure, hemoglobin, platelet count and HBV infection by logistic analyses, INR was shown as an independent variable [odds ratio (OR)=3.650; 95%CI: 1.372-9.714, P=0.010]. Considering the effect of liver cirrhosis on results, a sub-group analysis was performed and the study population was restricted to those patients with cirrhosis. Univariate analysis showed that diabetic patients had a higher INR than non-diabetic patients (1.43 ± 0.51 vs 1.25 ± 0.23, P=0.041). After controlling for confounding effect of age, SBP, hemoglobin, platelet count and HBV infection by logistic analyses, INR level remained as the sole independent variable (OR=5.161; 95%CI: 1.618-16.455, P=0.006). No significant difference in the relationship between INR level and fasting glucose was shown by Pearson test (r=0.070, P=0.184). Among the 63 diabetic patients, 35 (55.6%) patients had been diagnosed with DM for more than 5 years, 23 (36.5%) received oral anti-diabetic regimens, 11 (17.5%) received insulin, and 30 (47.6%) reported relying on diet alone to control serum glucose levels. No significant differences were found for the association between DM duration/treatment and INR level, except for the age at diabetes diagnosis. CONCLUSION: The INR level was increased in HCC patients with DM and these patients should be monitored for the coagulation function in clinical practice. 展开更多
关键词 International normalized ratio COAGULATION function Diabetes MELLITUS HEPATOCELLULAR carcinoma Chinese PATIENTS
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Distributions of Ratios: From Random Variables to Random Matrices 被引量:1
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作者 Thu Pham-Gia Noyan Turkkan 《Open Journal of Statistics》 2011年第2期93-104,共12页
The ratio R of two random quantities is frequently encountered in probability and statistics. But while for unidimensional statistical variables the distribution of R can be computed relatively easily, for symmetric p... The ratio R of two random quantities is frequently encountered in probability and statistics. But while for unidimensional statistical variables the distribution of R can be computed relatively easily, for symmetric positive definite random matrices, this ratio can take various forms and its distribution, and even its definition, can offer many challenges. However, for the distribution of its determinant, Meijer G-function often provides an effective analytic and computational tool, applicable at any division level, because of its reproductive property. 展开更多
关键词 Matrix Variate BETA DISTRIBUTION Generalized-F DISTRIBUTION ratios Meijer G-function Wishart DISTRIBUTION ratio
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Role-based approaches for operational task-resource flexible matching model and algorithm
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作者 Zhigang Zou Wangfang Che +2 位作者 Fuling Mu Yiqian Chao Bo Zhang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2017年第1期67-80,共14页
In order to solve the problem that previous relation researches in operational task-resource matching are hard to flexible computing for generating a new matching scheme from the existing scheme under the condition of... In order to solve the problem that previous relation researches in operational task-resource matching are hard to flexible computing for generating a new matching scheme from the existing scheme under the condition of operational tasks or resources adjusted in uncertainty cases, role-based approaches to operational task-resource flexible matching model and algorithm are proposed in the paper for flexible matching operational tasks with resources. Firstly, through introducing the concept of roles, the role-based calculation framework of operational task-resource flexible matching is constructed. Secondly, two aspect indexes about resource utilization ratio (RUR) and time utilization ratio (TUR) are given to reflect operational task-resource matching quality (TRMQ), which can be regarded as the objective function for modeling role-based operational task-resource flexible matching mathematical formulation. On the basis of this, the role-based artificial bee colony (RABC) algorithm, including five specific calculating operators, is put forward for solving the flexible matching problem with double encoding on operational tasks and resources by roles. Finally, via comparing with the previous methods in application cases, it can be validated that role-based model and proposed algorithm are more effective, which can be used to obtain a new incremental scheme from the existing matching scheme for adopting the operational tasks or resources adjustment. Moreover, there are flexible computation advantages of the approaches proposed in this paper to solve the problem about operational task-resource matching in large-scale. © 1990-2011 Beijing Institute of Aerospace Information. 展开更多
关键词 Aspect ratio functionS Optimization
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Preliminary analysis of teleseismic receiver functions of the Ningxia and its adjacent area 被引量:2
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作者 Xiaoqing Xu Xuzhang Shen +2 位作者 Chang Ming Guofu Luo Yao Lin 《Earthquake Science》 CSCD 2012年第1期47-53,共7页
The teleseismic receiver functions of digital seismic network of Ningxia and its adjacent area are calculated with two different Gauss filter factors. The accuracy and stability of the receiver functions are discussed... The teleseismic receiver functions of digital seismic network of Ningxia and its adjacent area are calculated with two different Gauss filter factors. The accuracy and stability of the receiver functions are discussed. The h-k stacking method is applied to estimate the crustal thickness and velocity ratio beneath seismic stations. The results indicate that there are sharp changes of crustal thickness and velocity ratio in the studied region. This region is located in the northeastern margin of Tibet, and also a junction of several first-grade blocks. The large contrast of crustal structure in this region is considered to be resulted from the interaction of these blocks. Our results are helpful to construct the completed model of the formation and evolution of the Tibet. Some local structures are also discussed combining with the geological faults. 展开更多
关键词 receiver function Ningxia crustal thickness velocity ratio
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Characterization of the Crustal Thickness and Poisson's Ratio of the Binchuan Region
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作者 Deng Jiamei Jin Mingpei +4 位作者 Chen Jia Gao Qiong Zhang Huaying Wang Jun Ye Beng 《Earthquake Research in China》 CSCD 2017年第1期79-89,共11页
This paper presents the changes of crust thickness and Poisson's ratios distribution in the Binchuan region, where the first air-gun transmitting station and it's a small dense array were deployed. From September 20... This paper presents the changes of crust thickness and Poisson's ratios distribution in the Binchuan region, where the first air-gun transmitting station and it's a small dense array were deployed. From September 2011 to January 2014, more than 239 teleseismic events of M≥ 6.0 were recorded in 16 stations in the Binchuan region. Their P-wave receiver functions were analyzed respectively. The high spatial resolution result shows that the average crust thickness of Binchuan region is 45.3km, it follows the rule of "deeper in the north and east part, shallower in the south and west part. " The deepest region is in Xiaoyindian Station; the crust thickness is 47.9km; the shallowest region is in Paiying Station, it has the thickness of 42. lkm. It shows that the deeper Moho surface nearby the Chenghai fault and shallower nearby the Honghe fault; the isoline distribution of thickness changes greatly nearby the Chenghai fault and slowly nearby the Honghe fault. From the distribution of Poisson's ratios, it is unevenly in the study area with a great difference from the north part to the south part, which shows a characteristic of "lower in the north, higher in the south". The Poisson's ratio nearby the Honghe fault is medium too high ( 0. 26 ≤ σ≤0. 29 ) ; lower nearby the Chenghai fault ( ≤0. 26). This paper concludes the possible reason of different characteristic between Poisson's ratio and crust thickness is thicker in the upper crust in the Binchuan region. 展开更多
关键词 Crustal thickness Poisson's ratio Receiver function The Binchuan region
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<i>Ratanasampil</i>(Tibetan Medicine, RNSP) Reduces <i>β</i>-Amyloid Protein (Aβ) and Pro-Inflammatory Factor Levels and Improves Cognitive Functions in Mild-to-Moderate Alzheimer’s Disease (AD) Patients Living at High Altitude 被引量:5
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作者 Aiqin Zhu Aiqi Xi +7 位作者 Guofeng Li Yinglan Li Baoxia Liao Xing Zhong Jingping Zhou Sonqin Gu Meihua Yu Yide Chu 《Journal of Behavioral and Brain Science》 2012年第1期82-91,共10页
Ratanasampil (RNSP) is a traditional Tibetan medicine used for the treatment of stroke and cerebrovascular diseases. Previous discoveries that RNSP can reduce β-amyloid protein levels and increase learning and memory... Ratanasampil (RNSP) is a traditional Tibetan medicine used for the treatment of stroke and cerebrovascular diseases. Previous discoveries that RNSP can reduce β-amyloid protein levels and increase learning and memory in Alzheimer’s mouse models (Tg2576) led us to investigate whether RNSP can improve cognitive functions in Alzheimer’s patients. In this study, 146 AD patients living in Qinghai province received either one gram or 0.33 gram daily of RNSP for 16 weeks. Placebo patients received Piracetam. Serum Aβ40 and Aβ42 levels were measured at the beginning of the study and after 4 and 16 weeks of treatment. Compared to the same group before treatment, MMSE scores, ADAS-cog scores and ADL scores were significantly improved (p 0.05, p > 0.05). After 16-week treatment, serum TNF-α, IL-1β, IL-6 and Aβ42 levels were significantly decreased (p < 0. 01) in the high-dose RNSP group, whereas no significant differences were found in the low-dose and placebo groups. The Aβ42/Aβ40 ratio was significantly decreased after 4-week and 16-week treatment in the high-dose RNSP group (p < 0. 05, p < 0.01). Furthermore, serum Aβ42 concentrations had a strong positive correlation with TNF-α, IL-1β and IL-6 levels. There were no observable adverse effects in either treatment or control groups. We conclude that further clinical trials of RNSP in Alzheimer disease are warranted. 展开更多
关键词 Ratanasampil (RNSP Tibetan Medicine) Alzheimer’s Disease Β-AMYLOID Peptide Aβ42/Aβ40 ratio PRO-INFLAMMATORY Factors Cognitive function
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基于响应面回归模型的纤维混凝土力学性能分析 被引量:1
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作者 邓友生 孟丽青 +3 位作者 郑云方 邹新军 姚志刚 肇慧玲 《湖南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第9期177-187,共11页
为研究玄武岩纤维和纤维素纤维掺量对混杂纤维轻骨料高强混凝土抗压强度、抗折强度和劈裂抗拉强度的影响,构建响应面回归模型,对比分析其力学试验实测值和预测值,并结合渴求函数获得混凝土优化配合比.结果表明:此回归模型有效且可信度高... 为研究玄武岩纤维和纤维素纤维掺量对混杂纤维轻骨料高强混凝土抗压强度、抗折强度和劈裂抗拉强度的影响,构建响应面回归模型,对比分析其力学试验实测值和预测值,并结合渴求函数获得混凝土优化配合比.结果表明:此回归模型有效且可信度高,可用于分析试验结果;两种纤维交互作用、水灰比与纤维素纤维交互作用对抗压强度、抗折强度、劈裂抗拉强度影响显著;模型预测最优水灰比为0.30,纤维素纤维掺量为0.90 kg/m3,玄武岩纤维掺量为4.00 kg/m3,强度预测值与试验值间相对误差绝对值均小于5%,该回归模型可为混杂纤维轻骨料高强混凝土的配合比多目标优化提供参考. 展开更多
关键词 响应面方法 高强混凝土 混杂纤维 渴求函数 配合比优化
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Dynamical Behavior of Discrete Ratio-Dependent Predator-Prey System
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作者 Mingxia Duan Jiying Ma 《Open Journal of Applied Sciences》 CAS 2023年第3期396-413,共18页
In this paper, we propose a discrete ratio-dependent predator-prey system. The stability of the fixed points of this model is studied. At the same time, it is shown that the discrete model undergoes fold bifurcation a... In this paper, we propose a discrete ratio-dependent predator-prey system. The stability of the fixed points of this model is studied. At the same time, it is shown that the discrete model undergoes fold bifurcation and flip bifurcation by using bifurcation theory and the method of approximation by a flow. Numerical simulations are presented not only to demonstrate the consistence with our theoretical analyses, but also to exhibit the complex dynamical behaviors, such as the cascade of period-doubling bifurcation in period-2 and the chaotic sets. The Maximum Lyapunov exponents are numerically computed to confirm further the complexity of the dynamical behaviors. These results show that the direct discrete method has more rich dynamic behaviors than the discrete model obtained by Euler method. 展开更多
关键词 Discrete-Time Predator-Prey System ratio-Dependent functional Response Stability and Bifurcation Analysis
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The Crustal Thickness and Poissons Ratio Distribution in Guangdong and Its Adjacent Areas
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作者 Shen Yusong Kang Ying Xu Guoming 《Earthquake Research in China》 CSCD 2016年第1期108-118,共11页
Based on the teleseismic waveform data recorded by 82 permanent broadband stations in Guangdong Province and its adjacent areas including Fujian, Jiangxi, Hunan, Guangxi, Hainan and Taiwan, we calculate body wave rece... Based on the teleseismic waveform data recorded by 82 permanent broadband stations in Guangdong Province and its adjacent areas including Fujian, Jiangxi, Hunan, Guangxi, Hainan and Taiwan, we calculate body wave receiver functions under all stations, and obtain the crustal thickness and average Poisson's ratio beneath all stations by the H-K stacking-search method of receiver function. The results show that the crustal thickness with an average thickness of 29. 5km in Guangdong Province and its adjacent areas ranges between 26. 8km and 33. 6kin and gradually thins from northwest to southeast. The crustal thickness in the Zhujiang Delta, western Guangdong, Nanning and Nan'ao areas is relatively thinner and ranges between 25. 0km and 28. 0km. The minimum crustal thickness is about 26km beneath Wengtian, Hainan and the Zhanjiang zone and Shangchuan Island in Guangdong. The crustal thickness in the zones of Mingxi, Fujian and Yongzhou, Hunan is thicker and varies between 31.0km and 34.0km. The distribution of Poisson's ratio in our study region ranges between 0.20 and 0. 29. Poisson's ratios in Southeast Hainan, the coastal areas of East Guangdong and West Fujian and the South Jiangxi have distinctly higher values than in others. It suggests that the various geothermal fields located in these areas have high heat flow values. The distribution of crustal thickness and Poisson's ratio has an obvious block feature and may be related to the distribution of faults and historical earthquakes. 展开更多
关键词 Receiver function Crustal thickness Poisson's ratio
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Global stability analysis of a ratio-dependent predator-prey system
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作者 鲁铁军 王美娟 刘妍 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2008年第4期495-500,共6页
A ratio dependent predator-prey system with Holling type Ⅲ functional response is considered. A sufficient condition of the global asymptotic stability for the positive equilibrium and existence of the limit cycle ar... A ratio dependent predator-prey system with Holling type Ⅲ functional response is considered. A sufficient condition of the global asymptotic stability for the positive equilibrium and existence of the limit cycle are given by studying locally asymp- totic stability of the positive equilibrium. The condition under which positive equilibrium is not a hyperbolic equilibrium is investigated using Hopf bifurcation. 展开更多
关键词 ratio-DEPENDENT global asymptotic stability functional response Hopf bifurcation
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Temporal variation of noise correlation function(NCF) in Beijing and surroundings:Its relation with climate events and implications 被引量:1
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作者 Changsheng Jiang Zhongliang Wu 《Earthquake Science》 CSCD 2009年第1期75-81,共7页
Noise correlation function (NCF) was calculated using the data of the Beijing Capital-Area Telemetered Digital Seismograph Network from June 12 to September 12, 2005. Signal-to-noise ratio (SNR) is used to charact... Noise correlation function (NCF) was calculated using the data of the Beijing Capital-Area Telemetered Digital Seismograph Network from June 12 to September 12, 2005. Signal-to-noise ratio (SNR) is used to characterize the quality of NCF at each station pair. The SNR (in dB) is shown to be dependent on the separation distance R of the station pair via SNR= A -BlogR. 'Normalized average SNR' for all the station pairs can then be calculated, as represented by the value of SNR taking R = 250 km in the empirical SNR-R relation, to measure the overall quality of the NCF result. The 'normalized average SNR' of the NCF shows temporal variation and is apparently dependent on the root-mean-square (RMS) velocity of the microseism. The result obtained by this experiment provides clues to the explanation of the properties of NCF, such as the dominant mechanism underlying (diffuse wave fields or uncorrelated sources), and the dependence of SNR on the time length of recordings. 展开更多
关键词 noise correlation function Beijing and surroundings signal-to-noise ratio
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基于全扇区统一占空比函数的Ⅰ型NPC三电平SVPWM载波化算法
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作者 吴扣林 袁庆伟 +2 位作者 谢晔源 刘洪德 钱为 《分布式能源》 2024年第4期11-22,共12页
Ⅰ型中性点钳位(neutral point clamped, NPC)三电平变流器作为中大容量新能源发电系统的核心设备,其调制策略直接影响变流器的能量转换效率、谐波特性和运行控制特性等。鉴于Ⅰ型三电平变流器的传统空间矢量脉宽调制(space vector puls... Ⅰ型中性点钳位(neutral point clamped, NPC)三电平变流器作为中大容量新能源发电系统的核心设备,其调制策略直接影响变流器的能量转换效率、谐波特性和运行控制特性等。鉴于Ⅰ型三电平变流器的传统空间矢量脉宽调制(space vector pulse width modulation, SVPWM)策略在实施过程中包含大量三角函数运算,基于三相静止坐标系进行调制算法的大小扇区判断和矢量作用时间计算等,并通过归纳整理,按照单调制波双载波的载波化思路,获得了适用于全扇区的三相统一的占空比函数。借助该占空比函数,变流器的数字控制器仅需通过简单的关系运算和数值计算,便可获得变流器功率管的控制信号,省去了大量三角函数计算,节约了硬件资源。此外,将SVPWM与正弦波脉宽调制(sinusoidal pulse width modulation, SPWM)+3次谐波注入调制算法进行对比,从调制波层面,揭示了这2种调制算法之间的内在差异。最后,通过仿真验证了该算法的有效性。 展开更多
关键词 三电平 SVPWM载波化 SPWM+3次谐波注入 三相静止坐标系 统一占空比函数
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