Although paid to upward shift response to global phenomenon at low zones did not receive increasing attention has been of plant species in altitude as a warming, research on this altitudinal and low latitudinal enoug...Although paid to upward shift response to global phenomenon at low zones did not receive increasing attention has been of plant species in altitude as a warming, research on this altitudinal and low latitudinal enough attention. In this study, an investigation was carried out to test the relationship between the upward spread of Moso bamboo （Phyllostachys pubescens） along altitudinal gradient and the increasing air temperature over the past decade within the Tianmu Mountain region, situated in southeastern China. Results showed that the peak elevation of Moso bamboo population establishment rose by an average of 9.8 m （±2.7 m） during the past decade and significant correlation existed with mean annual temperature （P 〈 0.0001, n = 339） but not with annual precipitation （P = 0.7, n = 339）, indicating that the upward shift of Moso bamboo along altitudinal gradients was driven primarily by warming temperatures. This upward shift could potentially reduce biodiversity by altering the species composition of the ecosystem. However, there is also the potential for increased carbon sequestration capacity of local forest systems, which would produce an additional carbon sink to combat rising atmospheric C02 concentrations and future global warming.展开更多
TiC/Ni_3Al composites have been prepared using upward infiltration method. The densification was performed by both Ni_3Al melt filling and TiC sintering during the infiltration. The dissolution of TiC in liquid Ni_3A...TiC/Ni_3Al composites have been prepared using upward infiltration method. The densification was performed by both Ni_3Al melt filling and TiC sintering during the infiltration. The dissolution of TiC in liquid Ni_3Al has been evidenced by finding Ni_3(Al,Ti)C after fast cooling in the TiC/Ni_3Al composites. The dissolution may be responsible for the infiltration and sintering. Compared with downward infiltration, the upward infiltration brought about higher strength and fracture toughness and shorter infiltration time. TiC/20 vol. pct Ni_3Al composite processed by upward infiltration had a flexural strength of 1476 MPa with a statistic Weibull modulus of 20.2 and a fracture toughness of 20.4 MPa . Better mechanical properties may be attributed to melt unidirectional movement in upward infiltration.展开更多
Ultra-thick steep coal seam mining will inevitably lead to the increase of greater and violent ground subsidence and deformation.A subsidence control method by inversely-inclined slicing and upward mining is proposed ...Ultra-thick steep coal seam mining will inevitably lead to the increase of greater and violent ground subsidence and deformation.A subsidence control method by inversely-inclined slicing and upward mining is proposed in this paper.By this method,the sequence of collapse of overlying strata and the direction of propagation of strata movement are changed,the extent of roof-side deformation thereby is lessened,and boundary angle of roof-side subsidence is reduced by 5°-10°.The mechanism of this mining method for control of strata movement has been evidenced by numerical simulation and experiments with similarity materials.A subsidence prediction model based on the variation of mining influence propagation angle can be used to evaluate the surface movement and deformation of the mining method.The application of the method in No.3 Mine in Yaojie mining area has yielded the expected result.展开更多
A theoretical discussion of the discharge effects of upward lightning simulated with a fine-resolution 2D thunderstorm model is performed in this paper,and the results reveal that the estimates of the total induced ch...A theoretical discussion of the discharge effects of upward lightning simulated with a fine-resolution 2D thunderstorm model is performed in this paper,and the results reveal that the estimates of the total induced charge on the upward lightning discharge channels range from 0.67 to 118.8 C,and the average value is 19.0 C,while the ratio of the induced charge on the leader channels to the total opposite-polarity charge in the discharge region ranges from 5.9%to 47.3%,with an average value of 14.7%.Moreover,the average value of the space electrostatic energy consumed by upward lightning is 1.06×10^9 J.The above values are lower than those related to intracloud lightning discharges.The density of the deposited opposite-polarity charge is comparable in magnitude to that of the preexisting charge in the discharge area,and the deposition of these opposite-polarity charges rapidly destroys the original space potential well in the discharge area and greatly reduces the space electric field strength.In addition,these opposite-polarity charges are redistributed with the development of thunderstorms.The space charge redistribution caused by lightning discharges partly accounts for the complexity of the charge structures in a thunderstorm,and the complexity gradually decreases with the charge neutralization process.展开更多
Objective Several well-exposed gravity flow deposits in the Early Cretaceous Lingshandao Formation provide a rare opportunity to study deep-water processes. The main objective of this work is to establish the spatial...Objective Several well-exposed gravity flow deposits in the Early Cretaceous Lingshandao Formation provide a rare opportunity to study deep-water processes. The main objective of this work is to establish the spatial and temporal relationships between the various gravity flow deposits, and thus to establish their sequence stratigraphic patterns and depositional conditions.展开更多
Numerical study about vortex-induced vibration （V/V） related to a flexible riser model in consideration of internal flow progressing inside has been performed. The main objective of this work is to investigate the c...Numerical study about vortex-induced vibration （V/V） related to a flexible riser model in consideration of internal flow progressing inside has been performed. The main objective of this work is to investigate the coupled fluid-structure interaction （FSI） taking place between tensioned riser model, external shear current and upward-progressing internal flow （from ocean bottom to surface）. A CAE technology behind the current research which combines structural software with the CFD technology has been proposed. According to the result from dynamic analysis, it has been found that the existence of upward-progressing internal flow does play an important role in determining the vibration mode （/dominant frequency）, vibration intensity and the magnitude of instantaneous vibration amplitude, when the velocity ratio of internal flow against external current is relatively high. As a rule, the larger the velocity of intemal flow is, the more it contributes to the dynamic vibration response of the flexible riser model. In addition, multi-modal vibration phenomenon has been widely observed, for asymmetric curvature along the riser span emerges in the case of external shear current being imposed.展开更多
Under ultra-supercritical pressure, the heat transfer characteristics of water in vertical upward 4- head internally ribbed tubes with a diameter of 28.65mm and thickness of 8mm were experimentally studied. The experi...Under ultra-supercritical pressure, the heat transfer characteristics of water in vertical upward 4- head internally ribbed tubes with a diameter of 28.65mm and thickness of 8mm were experimentally studied. The experiments were performed at P = 25- 34MPa, G = 450- 1800kg/（m^2·s） and q = 200 600kW/m^2. The results show that the pressure has only a moderate effect on the heat transfer of uhra-supercritical water when the water temperature is below the pseudocritical point. Sharp rise of the wall temperature near the pesudocritical region occurs earlier at a higher pressure. Increasing the mass velocity improves the heat transfer with a much stronger effect below the pesudocritical point than that above the pesudocritical point. For given pressure and mass velocity, the inner wall heat flux also shows a significant effect on the inner wall temperature, with a higher inner wall heat flux leading to a higher inner wall temperature. Increasing of inner wall heat flux leads to an early occurrence of sharp rise of the wall temperature. Correlations of heat transfer coefficients are also presented for vertical upward internally ribbed tubes.展开更多
Based on the character of upward slicing backfilling mining and the condition of Gonggeyingzi coal mine in Inner Mongolia,this paper describes the studies of the strata behavior and the stress distribution in the proc...Based on the character of upward slicing backfilling mining and the condition of Gonggeyingzi coal mine in Inner Mongolia,this paper describes the studies of the strata behavior and the stress distribution in the process of backfilling mining in extra-thick coal seams.This was achieved by setting up and analyzing the elastic foundation beam model using the ABAQUS software.The results show that:(1) With the gradual mining of different slices,the roof appears to bend continuously but does not break.The vertical stress in the roof decreases and the decreasing amplitude reduces,while the tensile stress in the roof grows with the mining slices and the maximum tensile stress will not exceed the allowable tensile stress.(2) The front vertical stress at the working face exceeds the rear vertical stress and both show a trend of decrease with decreasing amplitude of decrease.(3) The slices mined early have more influence on the surrounding rock than the later ones.Similarly,the strata behavior experiences the same trend.The field measured data show that the roof does not break during the mining process,which is consistent with the conclusion.展开更多
The paper presents an investigation of injection effects on the bedload transport rate. According to dimensional analysis, two dimensionless groups, an Einstein＇s parameter group and a modified densimetric Froude num...The paper presents an investigation of injection effects on the bedload transport rate. According to dimensional analysis, two dimensionless groups, an Einstein＇s parameter group and a modified densimetric Froude number group, were chosen to examine how injection affects the bedload transport rate. Experimental studies were conducted in an open-channel flume with an upward seepage zone. The sediment particles used for the test were 0.9 mm in diameter. The experimental results show that an increase in the injection velocity causes a reduction in the shear velocity excess, which is defined as the difference between the shear and critical shear velocities, leading to a reduction in the bedload transport rate. The equation for predicting the bedload transport rate in the presence of upward seepage was derived empirically. The proposed prediction method is suitable for engineering practice, since it only requires the undisturbed flow condition, properties of sediment particles, and the injection velocity.展开更多
The purpose of this paper is to introduce and discuss the concept of topical functions on upward sets. We give characterizations of topical functions in terms of upward sets.
A special device was designed to measure temperature difference in this study of heat transfer of water and oil cross flow inside vertical upward tubes. A new heat transfer correlation was obtained for cross flow. The...A special device was designed to measure temperature difference in this study of heat transfer of water and oil cross flow inside vertical upward tubes. A new heat transfer correlation was obtained for cross flow. The experimental results showed that the dependence of heat transfer on Reynolds is much smaller in a narrow space than that in a wide space. It was found that the heat transfer correlation of cross flow in a narrow space is obviously different from that in a wide space, and that the heat transfer correlation obtained in a wide space may not be applicable to the cross-flow heat transfer in a narrow space. Further, the single-phase heat transfer capability of water cross flow was compared with that of oil cross flow. The experimental results showed that the average heat transfer coefficient of water is about 2～3 times that ofoil when they have the same superficial velocity.展开更多
BACKGROUND The spontaneous resorption of lumbar disk herniations(LDHs)has been widely reported.However,the majority of these reports analyze the resorption of LDHs that were displaced backwards or downwards.There have...BACKGROUND The spontaneous resorption of lumbar disk herniations(LDHs)has been widely reported.However,the majority of these reports analyze the resorption of LDHs that were displaced backwards or downwards.There have been few reports on the spontaneous resorption of upwardly displaced L4/5 LDH that has caused femoral nerve symptoms.CASE SUMMARY A 55-year-old woman presented to our hospital with acute pain in her left leg.She had been suffering from recurrent lower back pain for approximately 1 year and began to feel pain accompanied with numbness at the anterior aspect of her left leg 7 d previously.On examination,a typical L4 nerve stimulation was noted.An upwardly displaced LDH at the L4/5 level was revealed by magnetic resonance imaging.The patient attained complete relief of her symptoms after 10 wk of nonsurgical treatment and the upwardly displaced herniation almost entirely disappeared.There was no recurrence during a follow-up of 2 years.CONCLUSION Clinicians should be aware that the nerves disturbed by LDHs vary according to the direction of the herniations and the probable resorption of upwardly displaced LDHs should be considered before making a decision on surgery.展开更多
The upward bubble velocity and the pierce length distributions in a sectionalwater model of the copper converter in Guixi Smelter in Jiangxi, China, were measured using atwo-contact electro-resistivity probe. In the c...The upward bubble velocity and the pierce length distributions in a sectionalwater model of the copper converter in Guixi Smelter in Jiangxi, China, were measured using atwo-contact electro-resistivity probe. In the case of using a single tuyere, the bubble velocitydistribution along longitudinal direction was similar to that derived from Guassian function. Beyondthe center of the longitudinal range, the bubble pierce length exhibited a sudden increase. Theupward bubble velocity at a specified location could go up to meters per second. Its probability ata fixed location obeys a lognormal function; the bubble pierce length there varies bellow a fewcentimeters. In the case of using multi-tuyeres, the upward bubble velocity was roughly uniformright above the tuyeres and showed a slow decrease beyond this region. The bubble pierce lengthwithin both of these two regions was roughly uniform. Its average value in the former region,however, was found to he somewhat lower than that in the later.展开更多
This paper studies. for the first time, the storm deposits of a carbonate sequence in the Sinian ZhangquFormation in northern Anhui. In the formation. a great number of calcareous trider sponge spicules were dis-cover...This paper studies. for the first time, the storm deposits of a carbonate sequence in the Sinian ZhangquFormation in northern Anhui. In the formation. a great number of calcareous trider sponge spicules were dis-covered in a distal storm turbidity sequence, which have provided further evidence for the correlation of theSinian Systems in North and South China from a view point of palaeontology.展开更多
The quantitative rules of the transfer and variation of errors,when the Gaussian integral functions F.(z) are evaluated sequentially by recurring,have been expounded.The traditional viewpoint to negate the applicabili...The quantitative rules of the transfer and variation of errors,when the Gaussian integral functions F.(z) are evaluated sequentially by recurring,have been expounded.The traditional viewpoint to negate the applicability and reliability of upward recursive formula in principle is amended.An optimal scheme of upward-and downward-joint recursions has been developed for the sequential F(z) computations.No additional accuracy is needed with the fundamental term of recursion because the absolute error of Fn(z) always decreases with the recursive approach.The scheme can be employed in modifying any of existent subprograms for Fn<z> computations.In the case of p-d-f-and g-type Gaussians,combining this method with Schaad's formulas can reduce,at least,the additive operations by a factor 40%;the multiplicative and exponential operations by a factor 60%.展开更多
In recent years,the development of rural e-commerce has been rapid but not balanced,and the upward scale of agricultural products is much smaller than the downward scale of industrial products.In the upward process of...In recent years,the development of rural e-commerce has been rapid but not balanced,and the upward scale of agricultural products is much smaller than the downward scale of industrial products.In the upward process of agricultural products,there are different models of e-commerce with farmers as the main body or cooperatives as the main body.Comparatively speaking,the difficulties in developing e-commerce for agricultural products with farmers as the main body are more prominent,while the development of e-commerce in agricultural products with cooperatives as the main body has more significant advantages.At present,there are still urgent problems to be solved,such as insufficient cold chain logistics facilities,insufficient scale and strength of cooperatives,and lack of systematic planning of local government's support policies for agricultural products.However,generally speaking,the upward trend for agricultural products based on cooperatives will be the mainstream of the development of agricultural electronic commerce in the future.展开更多
In this research work, the upward transition probabilities for the transition levels, 0<sup>+</sup> → 2<sup>+</sup>, 2<sup>+</sup> → 4<sup>+</sup>, 4<sup>+</s...In this research work, the upward transition probabilities for the transition levels, 0<sup>+</sup> → 2<sup>+</sup>, 2<sup>+</sup> → 4<sup>+</sup>, 4<sup>+</sup> → 6<sup>+</sup> and 6<sup>+</sup> → 8<sup>+</sup> levels of even-even neutron rich <sup>104-114</sup>Ru isotopes have been calculated by using the Global Best Fit (GBF) method. In addition, the associated parameters such as, Quadrupole moment and Deformation parameter of even-even <sup>104-114</sup>Ru have been calculated. The dependency of these nuclear parameters shows the nuclear magic number tendency.展开更多
To explore the status of undergraduates’WeChat usage and upward social comparison,and analyze the relationship between the above two variables.Totally 754 WeChat undergraduates were selected through poster recruitmen...To explore the status of undergraduates’WeChat usage and upward social comparison,and analyze the relationship between the above two variables.Totally 754 WeChat undergraduates were selected through poster recruitment from 5 colleges in Guangdong Province.They were investigated with Access Frequency to Social Networking Site Scale(AFSNSS),Upward Social Comparison Subscale of Iowa-Nwtherlands Comparison Orientation Measure(INCOM-USCS).The score of overall emotional engagement(OEE)of AFSNSS and the total standard score of INCOM–USCS(TSSI-U)were(22.41±4.70)and(0±4.5),respectively.The correlation between WeChat frequency and TSSI-U was not significant.TSSI-U was significantly positively correlated with the score of OEE and other items of AFSNSS(r=0.161~0.413,P<0.01).Multiple linear regression analysis showed that The scores of item 1,7and 8 of AFSNSS,as well as family economic status,grade ranking of academic performance(GRAP)and the purpose of WeChat use were postively correlated with TSSI-U(β=.104~.234,P<.05).Class cadre or not and origin were negatively correlated with TSSI-U(β=-.089,-.130,P<.05).Conclusion:It suggests that WeChat usage may be a related factor for undergraduates’upward social comparison.展开更多
This study is aim at investigate the current situation of higher vocational students receiving upward comparative parenting and the differences in upward comparative parenting among higher vocational college students ...This study is aim at investigate the current situation of higher vocational students receiving upward comparative parenting and the differences in upward comparative parenting among higher vocational college students with different demographic variables.By using the self-designed upward comparative parenting questionnaire to survey 1075 higher vocational college students,the results show that:In general,higher vocational college students receive the highest frequency of upward Comparative Parenting(2.95±1.57)on the level of learning diligence,and the frequency of upward Comparative Parenting(2.62±1.27)for male higher vocational students is higher than that for female students(2.39±1.17).The subjects from urban areas(2.56±1.29)were significantly higher than those from rural areas(2.39±1.14).Conclusion:upward comparat ive parenting is a common phenomenon among higher vocational college students in China.展开更多
基金funded by the National Nature Science Foundation of China (Grant No. 31070440,31270517)China QianRen Program,NSERC-Discovery GrantZhejiang A & F University Research and Development Fund (2012FR023)
文摘Although paid to upward shift response to global phenomenon at low zones did not receive increasing attention has been of plant species in altitude as a warming, research on this altitudinal and low latitudinal enough attention. In this study, an investigation was carried out to test the relationship between the upward spread of Moso bamboo （Phyllostachys pubescens） along altitudinal gradient and the increasing air temperature over the past decade within the Tianmu Mountain region, situated in southeastern China. Results showed that the peak elevation of Moso bamboo population establishment rose by an average of 9.8 m （±2.7 m） during the past decade and significant correlation existed with mean annual temperature （P 〈 0.0001, n = 339） but not with annual precipitation （P = 0.7, n = 339）, indicating that the upward shift of Moso bamboo along altitudinal gradients was driven primarily by warming temperatures. This upward shift could potentially reduce biodiversity by altering the species composition of the ecosystem. However, there is also the potential for increased carbon sequestration capacity of local forest systems, which would produce an additional carbon sink to combat rising atmospheric C02 concentrations and future global warming.
文摘TiC/Ni_3Al composites have been prepared using upward infiltration method. The densification was performed by both Ni_3Al melt filling and TiC sintering during the infiltration. The dissolution of TiC in liquid Ni_3Al has been evidenced by finding Ni_3(Al,Ti)C after fast cooling in the TiC/Ni_3Al composites. The dissolution may be responsible for the infiltration and sintering. Compared with downward infiltration, the upward infiltration brought about higher strength and fracture toughness and shorter infiltration time. TiC/20 vol. pct Ni_3Al composite processed by upward infiltration had a flexural strength of 1476 MPa with a statistic Weibull modulus of 20.2 and a fracture toughness of 20.4 MPa . Better mechanical properties may be attributed to melt unidirectional movement in upward infiltration.
基金sponsored by the National Natural Science Foundation of China(Nos.51574242 and 5097412).
文摘Ultra-thick steep coal seam mining will inevitably lead to the increase of greater and violent ground subsidence and deformation.A subsidence control method by inversely-inclined slicing and upward mining is proposed in this paper.By this method,the sequence of collapse of overlying strata and the direction of propagation of strata movement are changed,the extent of roof-side deformation thereby is lessened,and boundary angle of roof-side subsidence is reduced by 5°-10°.The mechanism of this mining method for control of strata movement has been evidenced by numerical simulation and experiments with similarity materials.A subsidence prediction model based on the variation of mining influence propagation angle can be used to evaluate the surface movement and deformation of the mining method.The application of the method in No.3 Mine in Yaojie mining area has yielded the expected result.
基金Project supported by China Postdoctoral Science Foundation （ 10000072311030 ）, Scienee technology Research Foundation of Shandong University of China {10000080398125）.
基金This research was supported by the National Key Research and Development Program of China(Grant No.2017YFC1501504)the National Natural Science Foundation of China(Grant Nos.41875003,41805002)the Open Research Program of the State Key Laboratory of Severe Weather(Grant No.2019LASW-A03).
文摘A theoretical discussion of the discharge effects of upward lightning simulated with a fine-resolution 2D thunderstorm model is performed in this paper,and the results reveal that the estimates of the total induced charge on the upward lightning discharge channels range from 0.67 to 118.8 C,and the average value is 19.0 C,while the ratio of the induced charge on the leader channels to the total opposite-polarity charge in the discharge region ranges from 5.9%to 47.3%,with an average value of 14.7%.Moreover,the average value of the space electrostatic energy consumed by upward lightning is 1.06×10^9 J.The above values are lower than those related to intracloud lightning discharges.The density of the deposited opposite-polarity charge is comparable in magnitude to that of the preexisting charge in the discharge area,and the deposition of these opposite-polarity charges rapidly destroys the original space potential well in the discharge area and greatly reduces the space electric field strength.In addition,these opposite-polarity charges are redistributed with the development of thunderstorms.The space charge redistribution caused by lightning discharges partly accounts for the complexity of the charge structures in a thunderstorm,and the complexity gradually decreases with the charge neutralization process.
基金supported by the National Natural Science Foundation of China(grant No.41372135)Shandong University of Science and Technology Research Fund(grant No.2015TDJH101)
文摘Objective Several well-exposed gravity flow deposits in the Early Cretaceous Lingshandao Formation provide a rare opportunity to study deep-water processes. The main objective of this work is to establish the spatial and temporal relationships between the various gravity flow deposits, and thus to establish their sequence stratigraphic patterns and depositional conditions.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41106077, 51109185 and 51109186)Zhejiang Provincial Natural Science Foundation of China (Grant Nos. R5110036 and Y5110071)+2 种基金Science Research Program of Science Technology Department of Zhejiang Province (Grant No. 2011C24005)Korea Research Foundation (Grant No. KRF-2008-D00556)Scientific Research Foundation of Zhejiang Ocean University
文摘Numerical study about vortex-induced vibration （V/V） related to a flexible riser model in consideration of internal flow progressing inside has been performed. The main objective of this work is to investigate the coupled fluid-structure interaction （FSI） taking place between tensioned riser model, external shear current and upward-progressing internal flow （from ocean bottom to surface）. A CAE technology behind the current research which combines structural software with the CFD technology has been proposed. According to the result from dynamic analysis, it has been found that the existence of upward-progressing internal flow does play an important role in determining the vibration mode （/dominant frequency）, vibration intensity and the magnitude of instantaneous vibration amplitude, when the velocity ratio of internal flow against external current is relatively high. As a rule, the larger the velocity of intemal flow is, the more it contributes to the dynamic vibration response of the flexible riser model. In addition, multi-modal vibration phenomenon has been widely observed, for asymmetric curvature along the riser span emerges in the case of external shear current being imposed.
基金Supported by the High Technology Research and Development Programme of China （No. 2002AA526012 ）and the National Natural Science Foundation of China （No. 50323001）.
文摘Under ultra-supercritical pressure, the heat transfer characteristics of water in vertical upward 4- head internally ribbed tubes with a diameter of 28.65mm and thickness of 8mm were experimentally studied. The experiments were performed at P = 25- 34MPa, G = 450- 1800kg/（m^2·s） and q = 200 600kW/m^2. The results show that the pressure has only a moderate effect on the heat transfer of uhra-supercritical water when the water temperature is below the pseudocritical point. Sharp rise of the wall temperature near the pesudocritical region occurs earlier at a higher pressure. Increasing the mass velocity improves the heat transfer with a much stronger effect below the pesudocritical point than that above the pesudocritical point. For given pressure and mass velocity, the inner wall heat flux also shows a significant effect on the inner wall temperature, with a higher inner wall heat flux leading to a higher inner wall temperature. Increasing of inner wall heat flux leads to an early occurrence of sharp rise of the wall temperature. Correlations of heat transfer coefficients are also presented for vertical upward internally ribbed tubes.
基金sponsored by the National Key Basic Research Program of China (No.2013CB227905)Qinglan Projects of Jiangsu Province
文摘Based on the character of upward slicing backfilling mining and the condition of Gonggeyingzi coal mine in Inner Mongolia,this paper describes the studies of the strata behavior and the stress distribution in the process of backfilling mining in extra-thick coal seams.This was achieved by setting up and analyzing the elastic foundation beam model using the ABAQUS software.The results show that:(1) With the gradual mining of different slices,the roof appears to bend continuously but does not break.The vertical stress in the roof decreases and the decreasing amplitude reduces,while the tensile stress in the roof grows with the mining slices and the maximum tensile stress will not exceed the allowable tensile stress.(2) The front vertical stress at the working face exceeds the rear vertical stress and both show a trend of decrease with decreasing amplitude of decrease.(3) The slices mined early have more influence on the surrounding rock than the later ones.Similarly,the strata behavior experiences the same trend.The field measured data show that the roof does not break during the mining process,which is consistent with the conclusion.
文摘The paper presents an investigation of injection effects on the bedload transport rate. According to dimensional analysis, two dimensionless groups, an Einstein＇s parameter group and a modified densimetric Froude number group, were chosen to examine how injection affects the bedload transport rate. Experimental studies were conducted in an open-channel flume with an upward seepage zone. The sediment particles used for the test were 0.9 mm in diameter. The experimental results show that an increase in the injection velocity causes a reduction in the shear velocity excess, which is defined as the difference between the shear and critical shear velocities, leading to a reduction in the bedload transport rate. The equation for predicting the bedload transport rate in the presence of upward seepage was derived empirically. The proposed prediction method is suitable for engineering practice, since it only requires the undisturbed flow condition, properties of sediment particles, and the injection velocity.
文摘The purpose of this paper is to introduce and discuss the concept of topical functions on upward sets. We give characterizations of topical functions in terms of upward sets.
文摘A special device was designed to measure temperature difference in this study of heat transfer of water and oil cross flow inside vertical upward tubes. A new heat transfer correlation was obtained for cross flow. The experimental results showed that the dependence of heat transfer on Reynolds is much smaller in a narrow space than that in a wide space. It was found that the heat transfer correlation of cross flow in a narrow space is obviously different from that in a wide space, and that the heat transfer correlation obtained in a wide space may not be applicable to the cross-flow heat transfer in a narrow space. Further, the single-phase heat transfer capability of water cross flow was compared with that of oil cross flow. The experimental results showed that the average heat transfer coefficient of water is about 2～3 times that ofoil when they have the same superficial velocity.
文摘BACKGROUND The spontaneous resorption of lumbar disk herniations(LDHs)has been widely reported.However,the majority of these reports analyze the resorption of LDHs that were displaced backwards or downwards.There have been few reports on the spontaneous resorption of upwardly displaced L4/5 LDH that has caused femoral nerve symptoms.CASE SUMMARY A 55-year-old woman presented to our hospital with acute pain in her left leg.She had been suffering from recurrent lower back pain for approximately 1 year and began to feel pain accompanied with numbness at the anterior aspect of her left leg 7 d previously.On examination,a typical L4 nerve stimulation was noted.An upwardly displaced LDH at the L4/5 level was revealed by magnetic resonance imaging.The patient attained complete relief of her symptoms after 10 wk of nonsurgical treatment and the upwardly displaced herniation almost entirely disappeared.There was no recurrence during a follow-up of 2 years.CONCLUSION Clinicians should be aware that the nerves disturbed by LDHs vary according to the direction of the herniations and the probable resorption of upwardly displaced LDHs should be considered before making a decision on surgery.
基金This work was financially supported by the National Natural Science Foundation of China(No.59874005).
文摘The upward bubble velocity and the pierce length distributions in a sectionalwater model of the copper converter in Guixi Smelter in Jiangxi, China, were measured using atwo-contact electro-resistivity probe. In the case of using a single tuyere, the bubble velocitydistribution along longitudinal direction was similar to that derived from Guassian function. Beyondthe center of the longitudinal range, the bubble pierce length exhibited a sudden increase. Theupward bubble velocity at a specified location could go up to meters per second. Its probability ata fixed location obeys a lognormal function; the bubble pierce length there varies bellow a fewcentimeters. In the case of using multi-tuyeres, the upward bubble velocity was roughly uniformright above the tuyeres and showed a slow decrease beyond this region. The bubble pierce lengthwithin both of these two regions was roughly uniform. Its average value in the former region,however, was found to he somewhat lower than that in the later.
文摘This paper studies. for the first time, the storm deposits of a carbonate sequence in the Sinian ZhangquFormation in northern Anhui. In the formation. a great number of calcareous trider sponge spicules were dis-covered in a distal storm turbidity sequence, which have provided further evidence for the correlation of theSinian Systems in North and South China from a view point of palaeontology.
文摘The quantitative rules of the transfer and variation of errors,when the Gaussian integral functions F.(z) are evaluated sequentially by recurring,have been expounded.The traditional viewpoint to negate the applicability and reliability of upward recursive formula in principle is amended.An optimal scheme of upward-and downward-joint recursions has been developed for the sequential F(z) computations.No additional accuracy is needed with the fundamental term of recursion because the absolute error of Fn(z) always decreases with the recursive approach.The scheme can be employed in modifying any of existent subprograms for Fn<z> computations.In the case of p-d-f-and g-type Gaussians,combining this method with Schaad's formulas can reduce,at least,the additive operations by a factor 40%;the multiplicative and exponential operations by a factor 60%.
基金Social Science Foundation of Yangtze University in 2015"Study on the Role of Farmers Professional Cooperatives in the Field of Agricultural Product Circulation"(2015csy007).
文摘In recent years,the development of rural e-commerce has been rapid but not balanced,and the upward scale of agricultural products is much smaller than the downward scale of industrial products.In the upward process of agricultural products,there are different models of e-commerce with farmers as the main body or cooperatives as the main body.Comparatively speaking,the difficulties in developing e-commerce for agricultural products with farmers as the main body are more prominent,while the development of e-commerce in agricultural products with cooperatives as the main body has more significant advantages.At present,there are still urgent problems to be solved,such as insufficient cold chain logistics facilities,insufficient scale and strength of cooperatives,and lack of systematic planning of local government's support policies for agricultural products.However,generally speaking,the upward trend for agricultural products based on cooperatives will be the mainstream of the development of agricultural electronic commerce in the future.
文摘In this research work, the upward transition probabilities for the transition levels, 0<sup>+</sup> → 2<sup>+</sup>, 2<sup>+</sup> → 4<sup>+</sup>, 4<sup>+</sup> → 6<sup>+</sup> and 6<sup>+</sup> → 8<sup>+</sup> levels of even-even neutron rich <sup>104-114</sup>Ru isotopes have been calculated by using the Global Best Fit (GBF) method. In addition, the associated parameters such as, Quadrupole moment and Deformation parameter of even-even <sup>104-114</sup>Ru have been calculated. The dependency of these nuclear parameters shows the nuclear magic number tendency.
文摘To explore the status of undergraduates’WeChat usage and upward social comparison,and analyze the relationship between the above two variables.Totally 754 WeChat undergraduates were selected through poster recruitment from 5 colleges in Guangdong Province.They were investigated with Access Frequency to Social Networking Site Scale(AFSNSS),Upward Social Comparison Subscale of Iowa-Nwtherlands Comparison Orientation Measure(INCOM-USCS).The score of overall emotional engagement(OEE)of AFSNSS and the total standard score of INCOM–USCS(TSSI-U)were(22.41±4.70)and(0±4.5),respectively.The correlation between WeChat frequency and TSSI-U was not significant.TSSI-U was significantly positively correlated with the score of OEE and other items of AFSNSS(r=0.161~0.413,P<0.01).Multiple linear regression analysis showed that The scores of item 1,7and 8 of AFSNSS,as well as family economic status,grade ranking of academic performance(GRAP)and the purpose of WeChat use were postively correlated with TSSI-U(β=.104~.234,P<.05).Class cadre or not and origin were negatively correlated with TSSI-U(β=-.089,-.130,P<.05).Conclusion:It suggests that WeChat usage may be a related factor for undergraduates’upward social comparison.
文摘This study is aim at investigate the current situation of higher vocational students receiving upward comparative parenting and the differences in upward comparative parenting among higher vocational college students with different demographic variables.By using the self-designed upward comparative parenting questionnaire to survey 1075 higher vocational college students,the results show that:In general,higher vocational college students receive the highest frequency of upward Comparative Parenting(2.95±1.57)on the level of learning diligence,and the frequency of upward Comparative Parenting(2.62±1.27)for male higher vocational students is higher than that for female students(2.39±1.17).The subjects from urban areas(2.56±1.29)were significantly higher than those from rural areas(2.39±1.14).Conclusion:upward comparat ive parenting is a common phenomenon among higher vocational college students in China.
