Using informational digital diagrams, we analyzed the snow event that occurred on Feb 26, 2006 and the sandstorm on Apr 11, 2006 in Xi'an. Results indicate that, under similar weather circumstances, different events ...Using informational digital diagrams, we analyzed the snow event that occurred on Feb 26, 2006 and the sandstorm on Apr 11, 2006 in Xi'an. Results indicate that, under similar weather circumstances, different events evidently exhibit unique vertical structure features. Informational digital diagrams provide a method for transitional weather prediction, a problem for present extrapolative analysis system.展开更多
AIM To explore whether copy number variations (CNVs) of toll-like receptor 7 (TLR7) are associated with susceptibility to chronic hepatitis B virus (HBV) infection. METHODS This study included 623 patients (495 males ...AIM To explore whether copy number variations (CNVs) of toll-like receptor 7 (TLR7) are associated with susceptibility to chronic hepatitis B virus (HBV) infection. METHODS This study included 623 patients (495 males and 128 females) with chronic hepatitis B virus infection (CHB) and 300 patients (135 females and 165 males) with acute hepatitis B virus infection (AHB) as controls. All CHB patients were further categorized according to disease progression after HBV infection (CHB, liver cirrhosis, or hepatocellular carcinoma). Copy numbers of the TLR7 gene were measured using the AccuCopy method chi(2) tests were used to evaluate the association between TLR7 CNVs and infection type. P values, odds ratios, and 95% confidence intervals (CIs) were used to estimate the effects of risk. RESULTS Among male patients, there were significant differences between the AHB group and CHB group in the distribution of TLR7 CNVs. Low copy numberof TLR7 was significantly associated with chronic HBV infection (OR = 0.329, 95% CI: 0.229-0.473, P > 0.001). Difference in TLR7 copy number was also found between AHB and CHB female patients, with low copy number again associated with an increased risk of chronic HBV infection (OR = 0.292, 95% CI: 0.173- 0.492, P < 0.001). However, there were no significant differences in TLR7 copy number among the three types of chronic HBV infection (CHB, liver cirrhosis, or hepatocellular carcinoma). In addition, there was no association between TLR7 copy number and titer of the HBV e antigen. CONCLUSION Low TLR7 copy number is a risk factor for chronic HBV infection but is not associated with later stages of disease progression.展开更多
Princeton Ocean Model (POM) is employed to investigate the Taiwan Warm Current (TWC) and its seasonal variations. Results show that the TWC exhibits pronounced seasonal variations in its sources,strength and flow patt...Princeton Ocean Model (POM) is employed to investigate the Taiwan Warm Current (TWC) and its seasonal variations. Results show that the TWC exhibits pronounced seasonal variations in its sources,strength and flow patterns. In summer, the TWC flows northeast in straight way and reaches around 32°N; it comes mainly from the Taiwan Strait, while its lower part is from the shelf-intrusion of the Kuroshio subsurface water (KSSW). In winter, coming mainly from the shelf-intrusion of the Kuroshio northeast of Taiwan, the TWC flows northward in a winding way and reaches up around 30°N. The Kuroshio intrusion also has distinct seasonal patterns. The shelf-intrusion of KSSW by upwelling is almost the same in four seasons with a little difference in strength; it is a persistent source of the TWC. However, Kuroshio surface water (KSW) can not intrude onto the shelf in summer, while in winter the intrusion of KSW always occurs. Additional experiments were conducted to examine effects of winds and transport through the Taiwan Strait on the TWC. In winter, northerly winds enhance the shelf-intrusion of the Kuroshio and spread northward, but hamper the northward inflow from the Taiwan Strait. In summer, the effect of the winds is confined in the surface layer, and less obvious than that of winter. Transport through the Taiwan Strait influences the TWC significantly. With the Taiwan Strait closed in the simulation, the TWC would be dramatically weakened.展开更多
Sound pressure amplitude will be attenuated with propagation distance in a certain rule when sound wave is propagated in shallow sea.When processing the attenuated signal,time-variant gain circuit is usually used to c...Sound pressure amplitude will be attenuated with propagation distance in a certain rule when sound wave is propagated in shallow sea.When processing the attenuated signal,time-variant gain circuit is usually used to compensate its diffusion loss.In this paper,spherical diffusion loss is compensated by digital potentiometer and operational circuit and further investigation is also made on compensation of cylindrical diffusion loss and transition from spherical diffusion loss to cylindrical diffusion loss.Finally,a new compensation model is proposed for unknown propagation loss for the purpose of adjusting the dynamic range of signal to meet the requirement of A/D conversion.展开更多
In this article, a theoretical model for predicting the equilibrium morphology of gas–liquid Janus droplets was built. Based on this model, the effects of bubble radius and volume ratio on morphology change was syste...In this article, a theoretical model for predicting the equilibrium morphology of gas–liquid Janus droplets was built. Based on this model, the effects of bubble radius and volume ratio on morphology change was systematically studied. The increase of bubble radius causes the two parts(bubble and oil drop) in Janus droplets tend to merge while the impact of volume ratio is complicated. When volume ratio increases, these two parts firstly tend to merge, then gradually separate. The accuracy of this model was verified by experimental results.展开更多
Mass occurrence of Salpafusiformis June 2007. In order to investigate its population was observed in the Southern Yellow Sea in May and recruitment and environmental adaptation, temporal variation of abundance, diel v...Mass occurrence of Salpafusiformis June 2007. In order to investigate its population was observed in the Southern Yellow Sea in May and recruitment and environmental adaptation, temporal variation of abundance, diel vertical migration (DVM) and length frequency distribution of both aggregate and solitary forms were studied with samples collected from eight months during September 2006 to August 2007. S. fusiformis presented in six months other than September and October 2006, and average abundance of aggregate and solitary forms peaked in June and May, respectively. In December, aggregate forms were absent in the bottom layer and performed irregular DVM from surface to 50 m depth, while solitary forms was too scarce to perform diel vertical distribution analysis. Both aggregate and solitary forms presented reverse DVM in May and June. They migrated upwards during daytime and concentrated in surface layer at sunset. The bimodal distribution of aggregate forms was found in April and the average size was largest in this month. In other months, the smaller aggregate forms (1-5 ram) dominated in populations except for May, when the modal size ranged from 2 to 8 mm. The average size of solitary forms was largest in December, followed by April. The skewed nomal distribution of solitary forms was found in May and June, with the modal size of 2-7 mm and 5-13 ram, respectively.展开更多
The structure of the optical waveguide of 2-bit electrooptic A/D converter with proton-exchange micro prisms is optimized by the finite-difference beam propagation method (FD-BPM). The electrode parameters of the conv...The structure of the optical waveguide of 2-bit electrooptic A/D converter with proton-exchange micro prisms is optimized by the finite-difference beam propagation method (FD-BPM). The electrode parameters of the converter are optimized by conformal mapping. The optimal parameters are a half-wave voltage of (Vπ= 4.5 V) and a bandwidth of (Δf=1.4 GHz).A normalized transmitted power of 69.75% is obtained by FD-BMP and the output waveguide gap is 300 μm.展开更多
Digital technologies offer unprecedented opportunities in addressing climate change as public policy requirements increasingly pervade national boundaries. Health issues now merge with those in education, the environm...Digital technologies offer unprecedented opportunities in addressing climate change as public policy requirements increasingly pervade national boundaries. Health issues now merge with those in education, the environment, energy, culture, gender, security, and the economy. They offer enormous potential in mobilizing for political action. But they also have a dark side. Outgoing U.S. President Barack Obama issued a warning that social media in particular poses an existential threat to democracy. Their pervasive influence during the 2016 American presidential election highlighted the potential for the spread of fake news and alternative facts. These realities must be recognized and addressed if meaningful policies on climate change and future sustainability are to be achieved. The challenges ahead require a re-examination of overarching trends in mass media that date back to the middle of the last century. Warnings from scientists, scholars, and community activists indicate that, on the issue of climate change, time is running out. In his Encyclical on Climate Change and Inequality, Pope Francis amplified the urgent call to action. But collectively, we need to rethink the profit driven ways in which our proliferating digital technologies mitigate potential steps toward a sustainable future. In a myriad of forms that go well beyond the seductive and addicting trends of endless hours spent online, new and proliferating digital toys and gadgets are neither carbon neutral, nor as some proponents would have us believe, do they hold the sole promise of innovation and job creation. Additionally, their potential must be harnessed to maintain rather than disrupt social stability.展开更多
The variations of ocean environmental parameters invariably result in variations of local modal wave numbers of a sound pressure field. The asymptotic Hankel transform with a short sliding window is applied to the com...The variations of ocean environmental parameters invariably result in variations of local modal wave numbers of a sound pressure field. The asymptotic Hankel transform with a short sliding window is applied to the complex sound pressure field in the water containing a mesoscale eddy to examine the variation of local modal wave numbers in such a range-dependent environment. The numerical simulation results show that modal wave number spectra obtained by this method can reflect the location and strength of a mesoscale eddy, therefore it can be used to monitor the strength and spatial scale of ocean mesoscale eddies.展开更多
The paper has presented the impact on the line protection performance with the introduction of MUs (merging units) in the process bus level. The paper begins with the introduction on modem digital substation structu...The paper has presented the impact on the line protection performance with the introduction of MUs (merging units) in the process bus level. The paper begins with the introduction on modem digital substation structure and process bus. Then, the paper describes the performances of different sensors such as CTs (current transformers), CVTs (capacitive voltage transformers), FOCS (fiber optical current transducers) and FOVS (fiber optical voltage transducers). With the use of above transducers together with MUs, the performance of distance protection function and line differential protection function have been investigated and presented. Finally, conclusions based on the study are presented in the paper.展开更多
The magnitude of river morphological changes are better analyzed through the use of quantitative approaches, wherein resolution accuracy and uncertainty assessment are treated as crucial key-factors. In this sense, th...The magnitude of river morphological changes are better analyzed through the use of quantitative approaches, wherein resolution accuracy and uncertainty assessment are treated as crucial key-factors. In this sense, the creation of precise DEMs (Digital Elevation Models) of rivers represents an affordable tool to analyze geomorphic variations and budgets, except for wetted areas, where reliable channel digitalization can normally be obtained only using expensive bathymetric surveys. The proposed work aims at improving channel surface models without having available bathymetric sensors, by deriving dry areas elevations from LiDAR data and water depth of wetted areas from aerial photos through a predictive depth-colour relationship. The methodology was applied to two different sub-reaches of the Piave River, a gravel-bed river which suffered severe flood events in 2010. Erosion and deposition patterns were identified through DEM differencing, showing a predominance of scour processes which can lead to channel instability situations. The bathymetric output was compared to other previously-derived models confirming the accuracy of the in-channel elevation estimates. Finally, a discussion on the role played by longitudinal protections during the studied flood events is proposed, focusing the attention on the incidence of two major bank erosions that removed significant volumes of stable areas.展开更多
To study the damage evolution of the metal plate in elastic and plastic deformation stages, an improved micropolar peridynamic model is proposed to simulate the deformation process and damage evolution of metal materi...To study the damage evolution of the metal plate in elastic and plastic deformation stages, an improved micropolar peridynamic model is proposed to simulate the deformation process and damage evolution of metal materials with variable Poisson’s ratios in the elastic-plastic stages. Firstly, both the stretching and bending moments of the bonds between the material points are added to peridynamic pairwise force functions, and the coordinate transformation of the micro-beam made up of bonds is deduced. Therefore, the numerical calculation implementation of the improved micropolar peridynamic model is obtained. Then, the strain values are obtained by solving the difference equation based on the displacement values of material points, and the stress values can be calculated according to generalized Hook’s law. The elastic and plastic deformation stages can be estimated based on the von Mises yield criterion, and different constitutive equations are adopted to simulate the damage evolution. Finally, the proposed micropolar peridynamic model is applied to simulate the damage evolution of a metal plate with a hole under velocity boundary conditions, and the effectiveness of the model is verified through experiments. In the experiments, the displacement and strain distributions in the stretching process are analyzed by the digital image correlation(DIC) method. By comparing the results, the proposed model is more accurate than the bond-based peridynamic model and the error of the proposed model is 7.2% lower than that of the bond-based peridynamic model. By loading different velocity boundary conditions, the relationship between the loads and damage evolution is studied.展开更多
文摘Using informational digital diagrams, we analyzed the snow event that occurred on Feb 26, 2006 and the sandstorm on Apr 11, 2006 in Xi'an. Results indicate that, under similar weather circumstances, different events evidently exhibit unique vertical structure features. Informational digital diagrams provide a method for transitional weather prediction, a problem for present extrapolative analysis system.
基金Supportedby National Natural Science Foundation of China,No.81273142
文摘AIM To explore whether copy number variations (CNVs) of toll-like receptor 7 (TLR7) are associated with susceptibility to chronic hepatitis B virus (HBV) infection. METHODS This study included 623 patients (495 males and 128 females) with chronic hepatitis B virus infection (CHB) and 300 patients (135 females and 165 males) with acute hepatitis B virus infection (AHB) as controls. All CHB patients were further categorized according to disease progression after HBV infection (CHB, liver cirrhosis, or hepatocellular carcinoma). Copy numbers of the TLR7 gene were measured using the AccuCopy method chi(2) tests were used to evaluate the association between TLR7 CNVs and infection type. P values, odds ratios, and 95% confidence intervals (CIs) were used to estimate the effects of risk. RESULTS Among male patients, there were significant differences between the AHB group and CHB group in the distribution of TLR7 CNVs. Low copy numberof TLR7 was significantly associated with chronic HBV infection (OR = 0.329, 95% CI: 0.229-0.473, P > 0.001). Difference in TLR7 copy number was also found between AHB and CHB female patients, with low copy number again associated with an increased risk of chronic HBV infection (OR = 0.292, 95% CI: 0.173- 0.492, P < 0.001). However, there were no significant differences in TLR7 copy number among the three types of chronic HBV infection (CHB, liver cirrhosis, or hepatocellular carcinoma). In addition, there was no association between TLR7 copy number and titer of the HBV e antigen. CONCLUSION Low TLR7 copy number is a risk factor for chronic HBV infection but is not associated with later stages of disease progression.
文摘Princeton Ocean Model (POM) is employed to investigate the Taiwan Warm Current (TWC) and its seasonal variations. Results show that the TWC exhibits pronounced seasonal variations in its sources,strength and flow patterns. In summer, the TWC flows northeast in straight way and reaches around 32°N; it comes mainly from the Taiwan Strait, while its lower part is from the shelf-intrusion of the Kuroshio subsurface water (KSSW). In winter, coming mainly from the shelf-intrusion of the Kuroshio northeast of Taiwan, the TWC flows northward in a winding way and reaches up around 30°N. The Kuroshio intrusion also has distinct seasonal patterns. The shelf-intrusion of KSSW by upwelling is almost the same in four seasons with a little difference in strength; it is a persistent source of the TWC. However, Kuroshio surface water (KSW) can not intrude onto the shelf in summer, while in winter the intrusion of KSW always occurs. Additional experiments were conducted to examine effects of winds and transport through the Taiwan Strait on the TWC. In winter, northerly winds enhance the shelf-intrusion of the Kuroshio and spread northward, but hamper the northward inflow from the Taiwan Strait. In summer, the effect of the winds is confined in the surface layer, and less obvious than that of winter. Transport through the Taiwan Strait influences the TWC significantly. With the Taiwan Strait closed in the simulation, the TWC would be dramatically weakened.
文摘Sound pressure amplitude will be attenuated with propagation distance in a certain rule when sound wave is propagated in shallow sea.When processing the attenuated signal,time-variant gain circuit is usually used to compensate its diffusion loss.In this paper,spherical diffusion loss is compensated by digital potentiometer and operational circuit and further investigation is also made on compensation of cylindrical diffusion loss and transition from spherical diffusion loss to cylindrical diffusion loss.Finally,a new compensation model is proposed for unknown propagation loss for the purpose of adjusting the dynamic range of signal to meet the requirement of A/D conversion.
基金Supported by the National Natural Science Foundation of China(21476121,21322604)Beijing Natural Science Foundation(2162020)a Foundation for Tsinghua Independent Research Projects(2014z21026)
文摘In this article, a theoretical model for predicting the equilibrium morphology of gas–liquid Janus droplets was built. Based on this model, the effects of bubble radius and volume ratio on morphology change was systematically studied. The increase of bubble radius causes the two parts(bubble and oil drop) in Janus droplets tend to merge while the impact of volume ratio is complicated. When volume ratio increases, these two parts firstly tend to merge, then gradually separate. The accuracy of this model was verified by experimental results.
基金Supports by the National Basic Research Program of China (973 Program) (No. 2011CB403604)the National Natural Science Foundation of China (No. 40631008)
文摘Mass occurrence of Salpafusiformis June 2007. In order to investigate its population was observed in the Southern Yellow Sea in May and recruitment and environmental adaptation, temporal variation of abundance, diel vertical migration (DVM) and length frequency distribution of both aggregate and solitary forms were studied with samples collected from eight months during September 2006 to August 2007. S. fusiformis presented in six months other than September and October 2006, and average abundance of aggregate and solitary forms peaked in June and May, respectively. In December, aggregate forms were absent in the bottom layer and performed irregular DVM from surface to 50 m depth, while solitary forms was too scarce to perform diel vertical distribution analysis. Both aggregate and solitary forms presented reverse DVM in May and June. They migrated upwards during daytime and concentrated in surface layer at sunset. The bimodal distribution of aggregate forms was found in April and the average size was largest in this month. In other months, the smaller aggregate forms (1-5 ram) dominated in populations except for May, when the modal size ranged from 2 to 8 mm. The average size of solitary forms was largest in December, followed by April. The skewed nomal distribution of solitary forms was found in May and June, with the modal size of 2-7 mm and 5-13 ram, respectively.
文摘The structure of the optical waveguide of 2-bit electrooptic A/D converter with proton-exchange micro prisms is optimized by the finite-difference beam propagation method (FD-BPM). The electrode parameters of the converter are optimized by conformal mapping. The optimal parameters are a half-wave voltage of (Vπ= 4.5 V) and a bandwidth of (Δf=1.4 GHz).A normalized transmitted power of 69.75% is obtained by FD-BMP and the output waveguide gap is 300 μm.
文摘Digital technologies offer unprecedented opportunities in addressing climate change as public policy requirements increasingly pervade national boundaries. Health issues now merge with those in education, the environment, energy, culture, gender, security, and the economy. They offer enormous potential in mobilizing for political action. But they also have a dark side. Outgoing U.S. President Barack Obama issued a warning that social media in particular poses an existential threat to democracy. Their pervasive influence during the 2016 American presidential election highlighted the potential for the spread of fake news and alternative facts. These realities must be recognized and addressed if meaningful policies on climate change and future sustainability are to be achieved. The challenges ahead require a re-examination of overarching trends in mass media that date back to the middle of the last century. Warnings from scientists, scholars, and community activists indicate that, on the issue of climate change, time is running out. In his Encyclical on Climate Change and Inequality, Pope Francis amplified the urgent call to action. But collectively, we need to rethink the profit driven ways in which our proliferating digital technologies mitigate potential steps toward a sustainable future. In a myriad of forms that go well beyond the seductive and addicting trends of endless hours spent online, new and proliferating digital toys and gadgets are neither carbon neutral, nor as some proponents would have us believe, do they hold the sole promise of innovation and job creation. Additionally, their potential must be harnessed to maintain rather than disrupt social stability.
文摘The variations of ocean environmental parameters invariably result in variations of local modal wave numbers of a sound pressure field. The asymptotic Hankel transform with a short sliding window is applied to the complex sound pressure field in the water containing a mesoscale eddy to examine the variation of local modal wave numbers in such a range-dependent environment. The numerical simulation results show that modal wave number spectra obtained by this method can reflect the location and strength of a mesoscale eddy, therefore it can be used to monitor the strength and spatial scale of ocean mesoscale eddies.
文摘The paper has presented the impact on the line protection performance with the introduction of MUs (merging units) in the process bus level. The paper begins with the introduction on modem digital substation structure and process bus. Then, the paper describes the performances of different sensors such as CTs (current transformers), CVTs (capacitive voltage transformers), FOCS (fiber optical current transducers) and FOVS (fiber optical voltage transducers). With the use of above transducers together with MUs, the performance of distance protection function and line differential protection function have been investigated and presented. Finally, conclusions based on the study are presented in the paper.
文摘The magnitude of river morphological changes are better analyzed through the use of quantitative approaches, wherein resolution accuracy and uncertainty assessment are treated as crucial key-factors. In this sense, the creation of precise DEMs (Digital Elevation Models) of rivers represents an affordable tool to analyze geomorphic variations and budgets, except for wetted areas, where reliable channel digitalization can normally be obtained only using expensive bathymetric surveys. The proposed work aims at improving channel surface models without having available bathymetric sensors, by deriving dry areas elevations from LiDAR data and water depth of wetted areas from aerial photos through a predictive depth-colour relationship. The methodology was applied to two different sub-reaches of the Piave River, a gravel-bed river which suffered severe flood events in 2010. Erosion and deposition patterns were identified through DEM differencing, showing a predominance of scour processes which can lead to channel instability situations. The bathymetric output was compared to other previously-derived models confirming the accuracy of the in-channel elevation estimates. Finally, a discussion on the role played by longitudinal protections during the studied flood events is proposed, focusing the attention on the incidence of two major bank erosions that removed significant volumes of stable areas.
基金The National Natural Science Foundation of China(No.51575101)
文摘To study the damage evolution of the metal plate in elastic and plastic deformation stages, an improved micropolar peridynamic model is proposed to simulate the deformation process and damage evolution of metal materials with variable Poisson’s ratios in the elastic-plastic stages. Firstly, both the stretching and bending moments of the bonds between the material points are added to peridynamic pairwise force functions, and the coordinate transformation of the micro-beam made up of bonds is deduced. Therefore, the numerical calculation implementation of the improved micropolar peridynamic model is obtained. Then, the strain values are obtained by solving the difference equation based on the displacement values of material points, and the stress values can be calculated according to generalized Hook’s law. The elastic and plastic deformation stages can be estimated based on the von Mises yield criterion, and different constitutive equations are adopted to simulate the damage evolution. Finally, the proposed micropolar peridynamic model is applied to simulate the damage evolution of a metal plate with a hole under velocity boundary conditions, and the effectiveness of the model is verified through experiments. In the experiments, the displacement and strain distributions in the stretching process are analyzed by the digital image correlation(DIC) method. By comparing the results, the proposed model is more accurate than the bond-based peridynamic model and the error of the proposed model is 7.2% lower than that of the bond-based peridynamic model. By loading different velocity boundary conditions, the relationship between the loads and damage evolution is studied.