This study evaluated the simulation performance of mesoscale convective system(MCS)-induced precipitation,focusing on three selected cases that originated from the Yellow Sea and propagated toward the Korean Peninsula...This study evaluated the simulation performance of mesoscale convective system(MCS)-induced precipitation,focusing on three selected cases that originated from the Yellow Sea and propagated toward the Korean Peninsula.The evaluation was conducted for the European Centre for Medium-Range Weather Forecasts(ECMWF)and National Centers for Environmental Prediction(NCEP)analysis data,as well as the simulation result using them as initial and lateral boundary conditions for the Weather Research and Forecasting model.Particularly,temperature and humidity profiles from 3D dropsonde observations from the National Center for Meteorological Science of the Korea Meteorological Administration served as validation data.Results showed that the ECMWF analysis consistently had smaller errors compared to the NCEP analysis,which exhibited a cold and dry bias in the lower levels below 850 hPa.The model,in terms of the precipitation simulations,particularly for high-intensity precipitation over the Yellow Sea,demonstrated higher accuracy when applying ECMWF analysis data as the initial condition.This advantage also positively influenced the simulation of rainfall events on the Korean Peninsula by reasonably inducing convective-favorable thermodynamic features(i.e.,warm and humid lower-level atmosphere)over the Yellow Sea.In conclusion,this study provides specific information about two global analysis datasets and their impacts on MCS-induced heavy rainfall simulation by employing dropsonde observation data.Furthermore,it suggests the need to enhance the initial field for MCS-induced heavy rainfall simulation and the applicability of assimilating dropsonde data for this purpose in the future.展开更多
The determination of the ultimate load-bearing capacity of structures made of elastoplastic heterogeneous materials under varying loads is of great importance for engineering analysis and design. Therefore, it is nece...The determination of the ultimate load-bearing capacity of structures made of elastoplastic heterogeneous materials under varying loads is of great importance for engineering analysis and design. Therefore, it is necessary to accurately predict the shakedown domains of these materials. The static shakedown theorem, also known as Melan's theorem, is a fundamental method used to predict the shakedown domains of structures and materials. Within this method, a key aspect lies in the construction and application of an appropriate self-equilibrium stress field(SSF). In the structural shakedown analysis, the SSF is typically constructed by governing equations that satisfy no external force(NEF) boundary conditions. However, we discover that directly applying these governing equations is not suitable for the shakedown analysis of heterogeneous materials. Researchers must consider the requirements imposed by the Hill-Mandel condition for boundary conditions and the physical significance of representative volume elements(RVEs). This paper addresses this issue and demonstrates that the sizes of SSFs vary under different boundary conditions, such as uniform displacement boundary conditions(DBCs), uniform traction boundary conditions(TBCs), and periodic boundary conditions(PBCs). As a result, significant discrepancies arise in the predicted shakedown domain sizes of heterogeneous materials. Built on the demonstrated relationship between SSFs under different boundary conditions, this study explores the conservative relationships among different shakedown domains, and provides proof of the relationship between the elastic limit(EL) factors and the shakedown loading factors under the loading domain of two load vertices. By utilizing numerical examples, we highlight the conservatism present in certain results reported in the existing literature. Among the investigated boundary conditions, the obtained shakedown domain is the most conservative under TBCs.Conversely, utilizing PBCs to construct an SSF for the shakedown analysis leads to less conservative lower bounds, indicating that PBCs should be employed as the preferred boundary conditions for the shakedown analysis of heterogeneous materials.展开更多
Objective To explore the feasibility of remotely obtaining complex information on traditional Chinese medicine(TCM)pulse conditions through voice signals.Methods We used multi-label pulse conditions as the entry point...Objective To explore the feasibility of remotely obtaining complex information on traditional Chinese medicine(TCM)pulse conditions through voice signals.Methods We used multi-label pulse conditions as the entry point and modeled and analyzed TCM pulse diagnosis by combining voice analysis and machine learning.Audio features were extracted from voice recordings in the TCM pulse condition dataset.The obtained features were combined with information from tongue and facial diagnoses.A multi-label pulse condition voice classification DNN model was built using 10-fold cross-validation,and the modeling methods were validated using publicly available datasets.Results The analysis showed that the proposed method achieved an accuracy of 92.59%on the public dataset.The accuracies of the three single-label pulse manifestation models in the test set were 94.27%,96.35%,and 95.39%.The absolute accuracy of the multi-label model was 92.74%.Conclusion Voice data analysis may serve as a remote adjunct to the TCM diagnostic method for pulse condition assessment.展开更多
The seismic response analysis of a tailing dam is studied using a fully coupled effective stress approach in conjunction with an advanced multi yield surface plastic constitutive model for tailing material.Strain cont...The seismic response analysis of a tailing dam is studied using a fully coupled effective stress approach in conjunction with an advanced multi yield surface plastic constitutive model for tailing material.Strain controlled static and cyclic triaxial tests were carried out to obtain the constitutive model for the tailing material.The tailing materials were collected from the Rampura Agucha tailing dam(Rajasthan State,India).A 2D nonlinear finite element(FE)model was then developed using different boundary conditions from the tailing embankment constructed using the downstream and upstream method of rising using OpenSees software.In first case,the model boundary was fixed in both the X and Y directions,and in the second case,viscous dashpots were introduced for both side and horizontal boundaries.The model was validated with experimental results on tailing material.Analyses were carried out considering five different earthquake motions,which were applied at the base.Comparisons of the different boundary conditions in terms of displacement flow vectors,pore pressure and stress-strain curves during shaking are presented.From the analysis,it was observed that the viscous boundary condition replicates the actual field conditions more accurately than the fixed boundary condition.In addition,it was found that the tailing embankment constructed by the downstream and upstream method of rising is not susceptible to liquefaction and lateral spreading for earthquake motions,even for a magnitude>5.5.展开更多
Based on Kirchhoff plate theory and the Rayleigh-Ritz method,the model for free vibration of rectangular plate with rectangular cutouts under arbitrary elastic boundary conditions is established by using the improved ...Based on Kirchhoff plate theory and the Rayleigh-Ritz method,the model for free vibration of rectangular plate with rectangular cutouts under arbitrary elastic boundary conditions is established by using the improved Fourier series in combination with the independent coordinate coupling method(ICCM).The effect of the cutout is taken into account by subtracting the energies of the cutouts from the total energies of the whole plate.The vibration displacement function of the hole domain is based on the coordinate system of the hole domain in this method.From the continuity condition of the vibration displacement function at the cutout,the transition matrix between the two coordinate systems is constructed,and the mass and stiffness matrices are completely obtained.As a result,the calculation is simplified and the computational efficiency of the solution is improved.In this paper,numerical examples and modal experiments are presented to validate the effectiveness of the modeling methods,and parameters related to influencing factors of the rectangular plate are analyzed to study the vibration characteristics.展开更多
The network of Himalayan roadways and highways connects some remote regions of valleys or hill slopes,which is vital for India’s socio-economic growth.Due to natural and artificial factors,frequency of slope instabil...The network of Himalayan roadways and highways connects some remote regions of valleys or hill slopes,which is vital for India’s socio-economic growth.Due to natural and artificial factors,frequency of slope instabilities along the networks has been increasing over last few decades.Assessment of stability of natural and artificial slopes due to construction of these connecting road networks is significant in safely executing these roads throughout the year.Several rock mass classification methods are generally used to assess the strength and deformability of rock mass.This study assesses slope stability along the NH-1A of Ramban district of North Western Himalayas.Various structurally and non-structurally controlled rock mass classification systems have been applied to assess the stability conditions of 14 slopes.For evaluating the stability of these slopes,kinematic analysis was performed along with geological strength index(GSI),rock mass rating(RMR),continuous slope mass rating(CoSMR),slope mass rating(SMR),and Q-slope in the present study.The SMR gives three slopes as completely unstable while CoSMR suggests four slopes as completely unstable.The stability of all slopes was also analyzed using a design chart under dynamic and static conditions by slope stability rating(SSR)for the factor of safety(FoS)of 1.2 and 1 respectively.Q-slope with probability of failure(PoF)1%gives two slopes as stable slopes.Stable slope angle has been determined based on the Q-slope safe angle equation and SSR design chart based on the FoS.The value ranges given by different empirical classifications were RMR(37-74),GSI(27.3-58.5),SMR(11-59),and CoSMR(3.39-74.56).Good relationship was found among RMR&SSR and RMR&GSI with correlation coefficient(R 2)value of 0.815 and 0.6866,respectively.Lastly,a comparative stability of all these slopes based on the above classification has been performed to identify the most critical slope along this road.展开更多
Structural health monitoring is widely utilized in outdoor environments,especially under harsh conditions,which can introduce noise into the monitoring system.Therefore,designing an effective denoising strategy to enh...Structural health monitoring is widely utilized in outdoor environments,especially under harsh conditions,which can introduce noise into the monitoring system.Therefore,designing an effective denoising strategy to enhance the performance of guided wave damage detection in noisy environments is crucial.This paper introduces a local temporal principal component analysis(PCA)reconstruction approach for denoising guided waves prior to implementing unsupervised damage detection,achieved through novel autoencoder-based reconstruction.Experimental results demonstrate that the proposed denoising method significantly enhances damage detection performance when guided waves are contaminated by noise,with SNR values ranging from 10 to-5 dB.Following the implementation of the proposed denoising approach,the AUC score can elevate from 0.65 to 0.96 when dealing with guided waves corrputed by noise at a level of-5 dB.Additionally,the paper provides guidance on selecting the appropriate number of components used in the denoising PCA reconstruction,aiding in the optimization of the damage detection in noisy conditions.展开更多
This paper studies the deterioration of bridge substructures utilizing the Long-Term Bridge Performance(LTBP)Program InfoBridge^(TM)and develops a survival model using Cox proportional hazards regression.The survival ...This paper studies the deterioration of bridge substructures utilizing the Long-Term Bridge Performance(LTBP)Program InfoBridge^(TM)and develops a survival model using Cox proportional hazards regression.The survival analysis is based on the National Bridge Inventory(NBI)dataset.The study calculates the survival rate of reinforced and prestressed concrete piles on bridges under marine conditions over a 29-year span(from 1992 to 2020).The state of Maryland is the primary focus of this study,with data from three neighboring regions,the District of Columbia,Virginia,and Delaware to expand the sample size.The data obtained from the National Bridge Inventory are condensed and filtered to acquire the most relevant information for model development.The Cox proportional hazards regression is applied to the condensed NBI data with six parameters:Age,ADT,ADTT,number of spans,span length,and structural length.Two survival models are generated for the bridge substructures:Reinforced and prestressed concrete piles in Maryland and reinforced and prestressed concrete piles in wet service conditions in the District of Columbia,Maryland,Delaware,and Virginia.Results from the Cox proportional hazards regression are used to construct Markov chains to demonstrate the sequence of the deterioration of bridge substructures.The Markov chains can be used as a tool to assist in the prediction and decision-making for repair,rehabilitation,and replacement of bridge piles.Based on the numerical model,the Pile Assessment Matrix Program(PAM)is developed to facilitate the assessment and maintenance of current bridge structures.The program integrates the NBI database with the inspection and research reports from various states’department of transportation,to serve as a tool for condition state simulation based on maintenance or rehabilitation strategies.展开更多
[ObJective] The research aimed to determine the geographic distribution map of system of Rana dybowskii. [Method] Four morphologic indices (body length, body weight, forelimb length, hindlimb length) of eight geogra...[ObJective] The research aimed to determine the geographic distribution map of system of Rana dybowskii. [Method] Four morphologic indices (body length, body weight, forelimb length, hindlimb length) of eight geographical populations of R.dybowskii which naturally distribute in Changhai Mountain and Xiaoxing'an Mountain were measured. Measure results were variance analyzed and cluster analyzed. [Result] Variance analysis showed: the genetic branching among the Dongfanghong male population( belongs to Wandashan) and Xiaoxing'an Mountain male population and Changbai Mountain male population were significantly different (P〈0.05) ; the genetic branching between the Hebei female population (belongs to Xiaoxing'an Mountain) and Changbai Mountain female population was significantly different (P〈0.05 ). Cluster analysis showed : male R.dybowskii can be divided into three groups : the first group included Quanyang, Tianbei, Chaoyang and Ddkouqin, the second group included Tieli and Anshan, the third group included Dongfanghong; and the female R. dybowskii can be divided into three groups : the first group included Quanyang and Chaoyang, the second group included Tianbei and Dakouqin, the third group included Hebei. [Condusion] The paper deduced that the Sanjiang Plain was the geographical origin center ofR. dybowskii which radiated to Changbai Mountain and Xiaoxing'an Mountain along the adverse current of Songhua River basin, therefore, the current distribution pattern of R. dybowskii was formed.展开更多
[Objective] This research was to study the correlation regional climatic characteristics and changing geographic distribution of Populus euphratica Oliv. (Salicaceae), as well as the adaption of Populus euphratica Oli...[Objective] This research was to study the correlation regional climatic characteristics and changing geographic distribution of Populus euphratica Oliv. (Salicaceae), as well as the adaption of Populus euphratica Oliv. to the climatic environment. [Method] The climatic characteristics, water source, groundwater and soil type in the distribution regions of Populus euphratica Oliv. and the effect of long-term human activities were comprehensively analyzed based an overview of Populus euphratica Oliv. and its distribution. [Result] Specific regional climatic characteristics and long term human activities are the principle determinants for the growth of Populus euphratica Oliv. The change of leaf shape is a distinct feature of Populus euphratica Oliv. in adapting to the climatic environment. Populus euphratica Oliv. withstands various environmental stresses by means of in vivo synthesis, transport and conversion of secondary phenolic metabolites. Effective protection and rehabilitation measures, and ecological water transport have obvious effect on the restoration and reconstruction of damaged ecological environment of Populus euphratica oasis. [Conclusion] This study is of great significance for the restoration of ecological environment in the arid inland regions, north-west China.展开更多
Through observing the phenology of two kinds of fruit trees,apple and peach trees,during their flowering periods in the past seven years,the meteorological conditions in the flowering stages were analyzed and summariz...Through observing the phenology of two kinds of fruit trees,apple and peach trees,during their flowering periods in the past seven years,the meteorological conditions in the flowering stages were analyzed and summarized in this paper.The late frost weather situation occurred in late April in Haiyang City also was elaborated in the paper.According to the data analysis,the terrain effect had induced a large temperature differences between north and south in April in Haiyang.Early flowering of fruit trees is as early as 5 to 8 days in the northern region than that in the southern region;accumulated temperature which was greater than or equal to 0 ℃ and the date of the temperature stably through a boundary,were the important meteorological indicators of the fruit trees' early flowering.The late frost in mid-late April is meteorological disasters of the fruit trees flowering period.The weather background of the occurred late frost,the disaster reasons and the measures for the prevention of late frost were proposed.展开更多
Drug use (DU), particularly injecting drug use (IDU) has been the main route of transmission and spread of Human Immunodeficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDSJ among injecting drug use...Drug use (DU), particularly injecting drug use (IDU) has been the main route of transmission and spread of Human Immunodeficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDSJ among injecting drug users (IDUs)[1]. Previous studies have proven that needles or cottons sharing during drug injection were major risk factors for HIV/AIDS transmission at the personal level[z4]. Being a social behavioral issue, HIV/AIDS related risk factors should be far beyond the personal level. Therefore, studies on HIV/AIDS related risk factors should focus not only on the individual factors, but also on the association between HIV/AIDS cases and macroscopic-factors, such as economic status, transportation, health care services, etc[1]. The impact of the macroscopic-factors on HIV/AIDS status might be either positive or negative, which are potentially reflected in promoting, delaying or detecting HIV/AIDS epidemics.展开更多
Based on the real-time wind direction and speed data from an automatic meteorological monitoring network in Shenzhen, the wind characteristics of Jue Diao Sha maritime area are analyzed. As indicated in the results, t...Based on the real-time wind direction and speed data from an automatic meteorological monitoring network in Shenzhen, the wind characteristics of Jue Diao Sha maritime area are analyzed. As indicated in the results, the wind speed of this area is higher than that over the land, the average wind speed is above 3 m/s and the probability for the maximum wind speed to drop below 20 m/s is above 90%. Moreover, the probability for the hourly swing angle of wind direction to become less than 50o is above 80%, suggesting that the wind conditions in the Jue Diao Sha area could meet the requirements of the sporting events. According to the numerical simulation, this area is the best selected site among three candidates. Furthermore, the characteristics of daily land and sea breezes are such that it is suggested the game will be best carried out from 1000 to 1700 Beijing Standard Time.展开更多
The paper studies ten major tree species occupying the space in naturalsecondary forests in Mao Er mountain area.The space is divided into horizon,elevation,slope,aspect and topographic position layer.The features of ...The paper studies ten major tree species occupying the space in naturalsecondary forests in Mao Er mountain area.The space is divided into horizon,elevation,slope,aspect and topographic position layer.The features of the species of trees areexamined using the concept of distribution width and the method of space statistics.Theconclusions of analysis indicate that Aspen and Asian White Birch community of forests inthe area would become failing,and the distribution of Mongolian Oak and Mongolian Lidenand Manchurian Walnut are Limited by the slope and aspect and topographic position.Elm,Maple,Manchurian Ash would become the major species constituting naturalsecondary forests in future in this area.展开更多
Yield and quality of sugar orange are closely related to meteorological conditions,especially the low temperature and cold injury in mature period of fruit. To study the influence of winter cold injury on sugar orange...Yield and quality of sugar orange are closely related to meteorological conditions,especially the low temperature and cold injury in mature period of fruit. To study the influence of winter cold injury on sugar orange industry of Guilin,the chilling injury weather in each county of Guilin planting sugar orange is analyzed,and the disastrous cold weather and its defense measures are studied. Frost,freezing and cold wave happen in Guilin winter sometimes,and the disastrous weather could seriously harm maturing sugar orange or that in the tree,causing peel coke,dehiscent fruit,fruit drop and quality decline. It can effectively reduce the loss by chilling injury and guarantee excellent quantity and high yield of sugar orange by timely understanding weather change information,scientifically managing water and fertilizer,and doing film cover well.展开更多
Approximately in the late-December of 2019, the coronavirus disease outbreak took place in China. COVID-19 (Coronavirus Disease 2019) is contagious and detrimental to the human body, which can even lead to death. As a...Approximately in the late-December of 2019, the coronavirus disease outbreak took place in China. COVID-19 (Coronavirus Disease 2019) is contagious and detrimental to the human body, which can even lead to death. As a result, the understanding of COVID-19 has become especially important. This paper studies four cases of anomalous disease-spreading in China (Guangdong Province, Heilongjiang province, Tianjin municipality, and Guizhou province) and analyzes four influencing factors of the transmission (temperature, transportation and passenger traffic volume, household size and distribution, and awareness). Major conclusions in this paper are as follows. Transportation and passenger traffic volume and the number of larger households are positively related to the extent of disease-spreading;the degree of awareness is negatively associated with the extent of disease-spreading. Provinces, municipalities, and autonomous regions with a more urbanized distribution of households are prone to experience a greater extent of disease transmission. Although the novel coronavirus prefers colder environment, temperature appears to be a secondary influencing factor, as regions with negative temperatures have fewer diagnoses. Disease transmission in Guangdong province is caused by a high volume of passenger traffic, large and urbanized households, and low awareness. Heilongjiang province is mainly a result of high passenger traffic volume, long travelling trips, and low public awareness. Guizhou province is benefited from high awareness, limited passenger volume, and scattered households. Tianjin municipality is protected from the severe disease-spreading owe to its beneficial temperature, low land transportation volume, and high public and government awareness.展开更多
Coupling equations used to calculate the chemical composition of substances by X-ray fluorescence analysis can be classified as empirical, theoretical or semi-empirical based on the method for determining the coeffici...Coupling equations used to calculate the chemical composition of substances by X-ray fluorescence analysis can be classified as empirical, theoretical or semi-empirical based on the method for determining the coefficients of the calibration function. The advantages and disadvantages of each class of equations are discussed. Recommendations for the selecting the optimum conditions for determining empirical correction coefficients and their control during analysis are provided.展开更多
Increasing performance parameters of hard disk drive (HDD) such as higher capacity and faster data access speed with decreasing physical size make HDD more susceptible to thermal effects. Contact temperature measureme...Increasing performance parameters of hard disk drive (HDD) such as higher capacity and faster data access speed with decreasing physical size make HDD more susceptible to thermal effects. Contact temperature measurement using thermocouple is not suitable for the rotating platter of HDD. Heat analysis using simulation software requires accurate initial parameter setting such as thermal (initial & boundary) conditions of certain regions. Temperature measurement using infrared (IR) system avoids these limitations;it is non-contact, responsive and does not require initial parameter setting. Thermal pattern distribution can be studied from the thermal images. However, emissivity of the target has to be known and calibration of the system is essential for accurate temperature reading. This paper showed that temperature within the HDD increases with ambient temperature and time, but the thermal distribution pattern in the HDD was not affected by different ambient temperatures. Three wall boundary conditions were conducted to study the thermal distribution pattern in the HDD. A solution was then proposed based on the results obtained from the experiments to improve the heat transfer rate and steady state temperature, and reduce the detrimental effects from high thermal generation in future prototypes. Another important finding was that the averaged temperature of the head cap was generally higher compared to that of the disk, as the spindle motor is the primary heat source within the HDD. Heat source analysis of HDD with IR system allows designers to have better visibility of the temperature generated in different components of the HDD. Proper cooling may enhance disk life as well as ensure the stability and integrity of the system.展开更多
BACKGROUND: Guillain-Barre syndrome (GBS) is an autoimmune disease which is characterized by demyelination of peripheral nerve and nerve root, and inflammatory reaction of lymphocyte and macrophage. Neuroelectrophy...BACKGROUND: Guillain-Barre syndrome (GBS) is an autoimmune disease which is characterized by demyelination of peripheral nerve and nerve root, and inflammatory reaction of lymphocyte and macrophage. Neuroelectrophysiological examination and cerebrospinal fluid (CSF) analysis are of significance for its diagnosis. OBJECTIVE: To study the association of neuroelectrophysiology and cerebrospinal fluid immunoglobulin (CSF-lg) with pathogenetic conditions of patients with GBS. DESIGN: Case control study SETTING: Department of Neurology, Shenzhen Municipal Shekou Group Hospital; Department of Neuroelectrophysiology, People's Hospital of Guangdong Province. PARTICIPANTS: A total of 32 GBS patients including 18 males and 14 females who aged from 17 to 72 years were selected as experimental group from the Department of Neurology, People's Hospital of Guang- dong Province from January 2004 to December 2005. All cases conformed with GBS diagnostic criteria established by Asbury in 1990 and they were divided into three types according to neurological criteria established by Chinese Neurology and Psychology Journal in 1993: mild, moderate and severe types. Another 30 patients with vascular headache were selected as control group from the same hospital including 14 males and 16 females who aged from 17 to 79 years. METHODS: ① Neuroelectrophysiological examination: Multiple-functional electromyography device provided by Nicolet Company, USA was used to measure nerve conduction velocity (NCV), including motor nerve conduction velocity (MCV) and sensory nerve conduction velocity (SCV); meanwhile, electromyologram (EMG), somatosensory evoked potential (SEP) and electroencephalogram (EEG) were also measured. ② Detection of CSF-lg: Concentrations of IgG, IgA and IgM were measured with immunofixation electrophoresis. ③Follow-up: Among 32 GBS patients, 14 cases received follow-up after treatment and the longest fol- low-up time was 1 year after onset. Among them, 8 cases were reexaminined with neuroelectrophysiological and CSF examinations. MAIN OUTCOME MEASURES: Results of NCV, EMG, SEP and EEG; comparison of CSF-lg content; results of follow-up examinations. RESULTS: All 32 GBS cases and 30 patients with vascular headache were involved in the final analysis. ① Abnormal rate of neuroelectrophysiological test: 75% of NCV, 88% of F-wave, 53% of MCV, 25% of SEP, 47% of EMG and 31% of EEG. There were no significant differences among various types (P 〉 0.05). ② Results of CSF-lg test: There were no significant differences among various types (P 〉 0.05); however, abnormalities in experimental group was higher than those in control group (P 〈 0.01). CONCLUSION : Results of follow-up study suggest that improvement of clinical symptom is earlier than neuroelectrophysiological recovery; MCV and EMG recoveries are faster than that of NCV; the earlier the abnormality of EMG, the poorer the recovery. CSF4g recovers normally along improvement of clinical symptoms. It is of significance for neuroelectrophysiology and abnormality of CSF-Ig to determine degree of peripheral nerve demyelination and prognosis.展开更多
基金supported by the Korea Meteorological Administration Research and Development Program “Developing Application Technology for Atmospheric Research Aircraft” (Grant No. KMA2018-00222)
文摘This study evaluated the simulation performance of mesoscale convective system(MCS)-induced precipitation,focusing on three selected cases that originated from the Yellow Sea and propagated toward the Korean Peninsula.The evaluation was conducted for the European Centre for Medium-Range Weather Forecasts(ECMWF)and National Centers for Environmental Prediction(NCEP)analysis data,as well as the simulation result using them as initial and lateral boundary conditions for the Weather Research and Forecasting model.Particularly,temperature and humidity profiles from 3D dropsonde observations from the National Center for Meteorological Science of the Korea Meteorological Administration served as validation data.Results showed that the ECMWF analysis consistently had smaller errors compared to the NCEP analysis,which exhibited a cold and dry bias in the lower levels below 850 hPa.The model,in terms of the precipitation simulations,particularly for high-intensity precipitation over the Yellow Sea,demonstrated higher accuracy when applying ECMWF analysis data as the initial condition.This advantage also positively influenced the simulation of rainfall events on the Korean Peninsula by reasonably inducing convective-favorable thermodynamic features(i.e.,warm and humid lower-level atmosphere)over the Yellow Sea.In conclusion,this study provides specific information about two global analysis datasets and their impacts on MCS-induced heavy rainfall simulation by employing dropsonde observation data.Furthermore,it suggests the need to enhance the initial field for MCS-induced heavy rainfall simulation and the applicability of assimilating dropsonde data for this purpose in the future.
基金Project supported by the National Natural Science Foundation of China (Nos. 52075070 and12302254)the Dalian City Supports Innovation and Entrepreneurship Projects for High-Level Talents (No. 2021RD16)the Liaoning Revitalization Talents Program (No. XLYC2002108)。
文摘The determination of the ultimate load-bearing capacity of structures made of elastoplastic heterogeneous materials under varying loads is of great importance for engineering analysis and design. Therefore, it is necessary to accurately predict the shakedown domains of these materials. The static shakedown theorem, also known as Melan's theorem, is a fundamental method used to predict the shakedown domains of structures and materials. Within this method, a key aspect lies in the construction and application of an appropriate self-equilibrium stress field(SSF). In the structural shakedown analysis, the SSF is typically constructed by governing equations that satisfy no external force(NEF) boundary conditions. However, we discover that directly applying these governing equations is not suitable for the shakedown analysis of heterogeneous materials. Researchers must consider the requirements imposed by the Hill-Mandel condition for boundary conditions and the physical significance of representative volume elements(RVEs). This paper addresses this issue and demonstrates that the sizes of SSFs vary under different boundary conditions, such as uniform displacement boundary conditions(DBCs), uniform traction boundary conditions(TBCs), and periodic boundary conditions(PBCs). As a result, significant discrepancies arise in the predicted shakedown domain sizes of heterogeneous materials. Built on the demonstrated relationship between SSFs under different boundary conditions, this study explores the conservative relationships among different shakedown domains, and provides proof of the relationship between the elastic limit(EL) factors and the shakedown loading factors under the loading domain of two load vertices. By utilizing numerical examples, we highlight the conservatism present in certain results reported in the existing literature. Among the investigated boundary conditions, the obtained shakedown domain is the most conservative under TBCs.Conversely, utilizing PBCs to construct an SSF for the shakedown analysis leads to less conservative lower bounds, indicating that PBCs should be employed as the preferred boundary conditions for the shakedown analysis of heterogeneous materials.
基金supported by Fundamental Research Funds from the Beijing University of Chinese Medicine(2023-JYB-KYPT-13)the Developmental Fund of Beijing University of Chinese Medicine(2020-ZXFZJJ-083).
文摘Objective To explore the feasibility of remotely obtaining complex information on traditional Chinese medicine(TCM)pulse conditions through voice signals.Methods We used multi-label pulse conditions as the entry point and modeled and analyzed TCM pulse diagnosis by combining voice analysis and machine learning.Audio features were extracted from voice recordings in the TCM pulse condition dataset.The obtained features were combined with information from tongue and facial diagnoses.A multi-label pulse condition voice classification DNN model was built using 10-fold cross-validation,and the modeling methods were validated using publicly available datasets.Results The analysis showed that the proposed method achieved an accuracy of 92.59%on the public dataset.The accuracies of the three single-label pulse manifestation models in the test set were 94.27%,96.35%,and 95.39%.The absolute accuracy of the multi-label model was 92.74%.Conclusion Voice data analysis may serve as a remote adjunct to the TCM diagnostic method for pulse condition assessment.
文摘The seismic response analysis of a tailing dam is studied using a fully coupled effective stress approach in conjunction with an advanced multi yield surface plastic constitutive model for tailing material.Strain controlled static and cyclic triaxial tests were carried out to obtain the constitutive model for the tailing material.The tailing materials were collected from the Rampura Agucha tailing dam(Rajasthan State,India).A 2D nonlinear finite element(FE)model was then developed using different boundary conditions from the tailing embankment constructed using the downstream and upstream method of rising using OpenSees software.In first case,the model boundary was fixed in both the X and Y directions,and in the second case,viscous dashpots were introduced for both side and horizontal boundaries.The model was validated with experimental results on tailing material.Analyses were carried out considering five different earthquake motions,which were applied at the base.Comparisons of the different boundary conditions in terms of displacement flow vectors,pore pressure and stress-strain curves during shaking are presented.From the analysis,it was observed that the viscous boundary condition replicates the actual field conditions more accurately than the fixed boundary condition.In addition,it was found that the tailing embankment constructed by the downstream and upstream method of rising is not susceptible to liquefaction and lateral spreading for earthquake motions,even for a magnitude>5.5.
基金support of this work by the National Natural Science Foundation of China(No.51405096)the Fundamental Research Funds for the Central Universities(HEUCF210710).
文摘Based on Kirchhoff plate theory and the Rayleigh-Ritz method,the model for free vibration of rectangular plate with rectangular cutouts under arbitrary elastic boundary conditions is established by using the improved Fourier series in combination with the independent coordinate coupling method(ICCM).The effect of the cutout is taken into account by subtracting the energies of the cutouts from the total energies of the whole plate.The vibration displacement function of the hole domain is based on the coordinate system of the hole domain in this method.From the continuity condition of the vibration displacement function at the cutout,the transition matrix between the two coordinate systems is constructed,and the mass and stiffness matrices are completely obtained.As a result,the calculation is simplified and the computational efficiency of the solution is improved.In this paper,numerical examples and modal experiments are presented to validate the effectiveness of the modeling methods,and parameters related to influencing factors of the rectangular plate are analyzed to study the vibration characteristics.
文摘The network of Himalayan roadways and highways connects some remote regions of valleys or hill slopes,which is vital for India’s socio-economic growth.Due to natural and artificial factors,frequency of slope instabilities along the networks has been increasing over last few decades.Assessment of stability of natural and artificial slopes due to construction of these connecting road networks is significant in safely executing these roads throughout the year.Several rock mass classification methods are generally used to assess the strength and deformability of rock mass.This study assesses slope stability along the NH-1A of Ramban district of North Western Himalayas.Various structurally and non-structurally controlled rock mass classification systems have been applied to assess the stability conditions of 14 slopes.For evaluating the stability of these slopes,kinematic analysis was performed along with geological strength index(GSI),rock mass rating(RMR),continuous slope mass rating(CoSMR),slope mass rating(SMR),and Q-slope in the present study.The SMR gives three slopes as completely unstable while CoSMR suggests four slopes as completely unstable.The stability of all slopes was also analyzed using a design chart under dynamic and static conditions by slope stability rating(SSR)for the factor of safety(FoS)of 1.2 and 1 respectively.Q-slope with probability of failure(PoF)1%gives two slopes as stable slopes.Stable slope angle has been determined based on the Q-slope safe angle equation and SSR design chart based on the FoS.The value ranges given by different empirical classifications were RMR(37-74),GSI(27.3-58.5),SMR(11-59),and CoSMR(3.39-74.56).Good relationship was found among RMR&SSR and RMR&GSI with correlation coefficient(R 2)value of 0.815 and 0.6866,respectively.Lastly,a comparative stability of all these slopes based on the above classification has been performed to identify the most critical slope along this road.
基金National Science Foundation of Zhejiang under Contract(LY23E010001)。
文摘Structural health monitoring is widely utilized in outdoor environments,especially under harsh conditions,which can introduce noise into the monitoring system.Therefore,designing an effective denoising strategy to enhance the performance of guided wave damage detection in noisy environments is crucial.This paper introduces a local temporal principal component analysis(PCA)reconstruction approach for denoising guided waves prior to implementing unsupervised damage detection,achieved through novel autoencoder-based reconstruction.Experimental results demonstrate that the proposed denoising method significantly enhances damage detection performance when guided waves are contaminated by noise,with SNR values ranging from 10 to-5 dB.Following the implementation of the proposed denoising approach,the AUC score can elevate from 0.65 to 0.96 when dealing with guided waves corrputed by noise at a level of-5 dB.Additionally,the paper provides guidance on selecting the appropriate number of components used in the denoising PCA reconstruction,aiding in the optimization of the damage detection in noisy conditions.
基金This research receives funding from the Maryland Department of Transportation State Highway Administration.
文摘This paper studies the deterioration of bridge substructures utilizing the Long-Term Bridge Performance(LTBP)Program InfoBridge^(TM)and develops a survival model using Cox proportional hazards regression.The survival analysis is based on the National Bridge Inventory(NBI)dataset.The study calculates the survival rate of reinforced and prestressed concrete piles on bridges under marine conditions over a 29-year span(from 1992 to 2020).The state of Maryland is the primary focus of this study,with data from three neighboring regions,the District of Columbia,Virginia,and Delaware to expand the sample size.The data obtained from the National Bridge Inventory are condensed and filtered to acquire the most relevant information for model development.The Cox proportional hazards regression is applied to the condensed NBI data with six parameters:Age,ADT,ADTT,number of spans,span length,and structural length.Two survival models are generated for the bridge substructures:Reinforced and prestressed concrete piles in Maryland and reinforced and prestressed concrete piles in wet service conditions in the District of Columbia,Maryland,Delaware,and Virginia.Results from the Cox proportional hazards regression are used to construct Markov chains to demonstrate the sequence of the deterioration of bridge substructures.The Markov chains can be used as a tool to assist in the prediction and decision-making for repair,rehabilitation,and replacement of bridge piles.Based on the numerical model,the Pile Assessment Matrix Program(PAM)is developed to facilitate the assessment and maintenance of current bridge structures.The program integrates the NBI database with the inspection and research reports from various states’department of transportation,to serve as a tool for condition state simulation based on maintenance or rehabilitation strategies.
文摘[ObJective] The research aimed to determine the geographic distribution map of system of Rana dybowskii. [Method] Four morphologic indices (body length, body weight, forelimb length, hindlimb length) of eight geographical populations of R.dybowskii which naturally distribute in Changhai Mountain and Xiaoxing'an Mountain were measured. Measure results were variance analyzed and cluster analyzed. [Result] Variance analysis showed: the genetic branching among the Dongfanghong male population( belongs to Wandashan) and Xiaoxing'an Mountain male population and Changbai Mountain male population were significantly different (P〈0.05) ; the genetic branching between the Hebei female population (belongs to Xiaoxing'an Mountain) and Changbai Mountain female population was significantly different (P〈0.05 ). Cluster analysis showed : male R.dybowskii can be divided into three groups : the first group included Quanyang, Tianbei, Chaoyang and Ddkouqin, the second group included Tieli and Anshan, the third group included Dongfanghong; and the female R. dybowskii can be divided into three groups : the first group included Quanyang and Chaoyang, the second group included Tianbei and Dakouqin, the third group included Hebei. [Condusion] The paper deduced that the Sanjiang Plain was the geographical origin center ofR. dybowskii which radiated to Changbai Mountain and Xiaoxing'an Mountain along the adverse current of Songhua River basin, therefore, the current distribution pattern of R. dybowskii was formed.
文摘[Objective] This research was to study the correlation regional climatic characteristics and changing geographic distribution of Populus euphratica Oliv. (Salicaceae), as well as the adaption of Populus euphratica Oliv. to the climatic environment. [Method] The climatic characteristics, water source, groundwater and soil type in the distribution regions of Populus euphratica Oliv. and the effect of long-term human activities were comprehensively analyzed based an overview of Populus euphratica Oliv. and its distribution. [Result] Specific regional climatic characteristics and long term human activities are the principle determinants for the growth of Populus euphratica Oliv. The change of leaf shape is a distinct feature of Populus euphratica Oliv. in adapting to the climatic environment. Populus euphratica Oliv. withstands various environmental stresses by means of in vivo synthesis, transport and conversion of secondary phenolic metabolites. Effective protection and rehabilitation measures, and ecological water transport have obvious effect on the restoration and reconstruction of damaged ecological environment of Populus euphratica oasis. [Conclusion] This study is of great significance for the restoration of ecological environment in the arid inland regions, north-west China.
文摘Through observing the phenology of two kinds of fruit trees,apple and peach trees,during their flowering periods in the past seven years,the meteorological conditions in the flowering stages were analyzed and summarized in this paper.The late frost weather situation occurred in late April in Haiyang City also was elaborated in the paper.According to the data analysis,the terrain effect had induced a large temperature differences between north and south in April in Haiyang.Early flowering of fruit trees is as early as 5 to 8 days in the northern region than that in the southern region;accumulated temperature which was greater than or equal to 0 ℃ and the date of the temperature stably through a boundary,were the important meteorological indicators of the fruit trees' early flowering.The late frost in mid-late April is meteorological disasters of the fruit trees flowering period.The weather background of the occurred late frost,the disaster reasons and the measures for the prevention of late frost were proposed.
基金supported by the National Scientific Research Mega-Project under the 12th Five-Year Plan of China(2012ZX10001001)
文摘Drug use (DU), particularly injecting drug use (IDU) has been the main route of transmission and spread of Human Immunodeficiency Virus (HIV)/Acquired Immune Deficiency Syndrome (AIDSJ among injecting drug users (IDUs)[1]. Previous studies have proven that needles or cottons sharing during drug injection were major risk factors for HIV/AIDS transmission at the personal level[z4]. Being a social behavioral issue, HIV/AIDS related risk factors should be far beyond the personal level. Therefore, studies on HIV/AIDS related risk factors should focus not only on the individual factors, but also on the association between HIV/AIDS cases and macroscopic-factors, such as economic status, transportation, health care services, etc[1]. The impact of the macroscopic-factors on HIV/AIDS status might be either positive or negative, which are potentially reflected in promoting, delaying or detecting HIV/AIDS epidemics.
基金Project on Meteorological Conditions for Selection of Site of Maritime Sporting Base for 26th Summer Universiade 2011
文摘Based on the real-time wind direction and speed data from an automatic meteorological monitoring network in Shenzhen, the wind characteristics of Jue Diao Sha maritime area are analyzed. As indicated in the results, the wind speed of this area is higher than that over the land, the average wind speed is above 3 m/s and the probability for the maximum wind speed to drop below 20 m/s is above 90%. Moreover, the probability for the hourly swing angle of wind direction to become less than 50o is above 80%, suggesting that the wind conditions in the Jue Diao Sha area could meet the requirements of the sporting events. According to the numerical simulation, this area is the best selected site among three candidates. Furthermore, the characteristics of daily land and sea breezes are such that it is suggested the game will be best carried out from 1000 to 1700 Beijing Standard Time.
文摘The paper studies ten major tree species occupying the space in naturalsecondary forests in Mao Er mountain area.The space is divided into horizon,elevation,slope,aspect and topographic position layer.The features of the species of trees areexamined using the concept of distribution width and the method of space statistics.Theconclusions of analysis indicate that Aspen and Asian White Birch community of forests inthe area would become failing,and the distribution of Mongolian Oak and Mongolian Lidenand Manchurian Walnut are Limited by the slope and aspect and topographic position.Elm,Maple,Manchurian Ash would become the major species constituting naturalsecondary forests in future in this area.
文摘Yield and quality of sugar orange are closely related to meteorological conditions,especially the low temperature and cold injury in mature period of fruit. To study the influence of winter cold injury on sugar orange industry of Guilin,the chilling injury weather in each county of Guilin planting sugar orange is analyzed,and the disastrous cold weather and its defense measures are studied. Frost,freezing and cold wave happen in Guilin winter sometimes,and the disastrous weather could seriously harm maturing sugar orange or that in the tree,causing peel coke,dehiscent fruit,fruit drop and quality decline. It can effectively reduce the loss by chilling injury and guarantee excellent quantity and high yield of sugar orange by timely understanding weather change information,scientifically managing water and fertilizer,and doing film cover well.
文摘Approximately in the late-December of 2019, the coronavirus disease outbreak took place in China. COVID-19 (Coronavirus Disease 2019) is contagious and detrimental to the human body, which can even lead to death. As a result, the understanding of COVID-19 has become especially important. This paper studies four cases of anomalous disease-spreading in China (Guangdong Province, Heilongjiang province, Tianjin municipality, and Guizhou province) and analyzes four influencing factors of the transmission (temperature, transportation and passenger traffic volume, household size and distribution, and awareness). Major conclusions in this paper are as follows. Transportation and passenger traffic volume and the number of larger households are positively related to the extent of disease-spreading;the degree of awareness is negatively associated with the extent of disease-spreading. Provinces, municipalities, and autonomous regions with a more urbanized distribution of households are prone to experience a greater extent of disease transmission. Although the novel coronavirus prefers colder environment, temperature appears to be a secondary influencing factor, as regions with negative temperatures have fewer diagnoses. Disease transmission in Guangdong province is caused by a high volume of passenger traffic, large and urbanized households, and low awareness. Heilongjiang province is mainly a result of high passenger traffic volume, long travelling trips, and low public awareness. Guizhou province is benefited from high awareness, limited passenger volume, and scattered households. Tianjin municipality is protected from the severe disease-spreading owe to its beneficial temperature, low land transportation volume, and high public and government awareness.
文摘Coupling equations used to calculate the chemical composition of substances by X-ray fluorescence analysis can be classified as empirical, theoretical or semi-empirical based on the method for determining the coefficients of the calibration function. The advantages and disadvantages of each class of equations are discussed. Recommendations for the selecting the optimum conditions for determining empirical correction coefficients and their control during analysis are provided.
文摘Increasing performance parameters of hard disk drive (HDD) such as higher capacity and faster data access speed with decreasing physical size make HDD more susceptible to thermal effects. Contact temperature measurement using thermocouple is not suitable for the rotating platter of HDD. Heat analysis using simulation software requires accurate initial parameter setting such as thermal (initial & boundary) conditions of certain regions. Temperature measurement using infrared (IR) system avoids these limitations;it is non-contact, responsive and does not require initial parameter setting. Thermal pattern distribution can be studied from the thermal images. However, emissivity of the target has to be known and calibration of the system is essential for accurate temperature reading. This paper showed that temperature within the HDD increases with ambient temperature and time, but the thermal distribution pattern in the HDD was not affected by different ambient temperatures. Three wall boundary conditions were conducted to study the thermal distribution pattern in the HDD. A solution was then proposed based on the results obtained from the experiments to improve the heat transfer rate and steady state temperature, and reduce the detrimental effects from high thermal generation in future prototypes. Another important finding was that the averaged temperature of the head cap was generally higher compared to that of the disk, as the spindle motor is the primary heat source within the HDD. Heat source analysis of HDD with IR system allows designers to have better visibility of the temperature generated in different components of the HDD. Proper cooling may enhance disk life as well as ensure the stability and integrity of the system.
文摘BACKGROUND: Guillain-Barre syndrome (GBS) is an autoimmune disease which is characterized by demyelination of peripheral nerve and nerve root, and inflammatory reaction of lymphocyte and macrophage. Neuroelectrophysiological examination and cerebrospinal fluid (CSF) analysis are of significance for its diagnosis. OBJECTIVE: To study the association of neuroelectrophysiology and cerebrospinal fluid immunoglobulin (CSF-lg) with pathogenetic conditions of patients with GBS. DESIGN: Case control study SETTING: Department of Neurology, Shenzhen Municipal Shekou Group Hospital; Department of Neuroelectrophysiology, People's Hospital of Guangdong Province. PARTICIPANTS: A total of 32 GBS patients including 18 males and 14 females who aged from 17 to 72 years were selected as experimental group from the Department of Neurology, People's Hospital of Guang- dong Province from January 2004 to December 2005. All cases conformed with GBS diagnostic criteria established by Asbury in 1990 and they were divided into three types according to neurological criteria established by Chinese Neurology and Psychology Journal in 1993: mild, moderate and severe types. Another 30 patients with vascular headache were selected as control group from the same hospital including 14 males and 16 females who aged from 17 to 79 years. METHODS: ① Neuroelectrophysiological examination: Multiple-functional electromyography device provided by Nicolet Company, USA was used to measure nerve conduction velocity (NCV), including motor nerve conduction velocity (MCV) and sensory nerve conduction velocity (SCV); meanwhile, electromyologram (EMG), somatosensory evoked potential (SEP) and electroencephalogram (EEG) were also measured. ② Detection of CSF-lg: Concentrations of IgG, IgA and IgM were measured with immunofixation electrophoresis. ③Follow-up: Among 32 GBS patients, 14 cases received follow-up after treatment and the longest fol- low-up time was 1 year after onset. Among them, 8 cases were reexaminined with neuroelectrophysiological and CSF examinations. MAIN OUTCOME MEASURES: Results of NCV, EMG, SEP and EEG; comparison of CSF-lg content; results of follow-up examinations. RESULTS: All 32 GBS cases and 30 patients with vascular headache were involved in the final analysis. ① Abnormal rate of neuroelectrophysiological test: 75% of NCV, 88% of F-wave, 53% of MCV, 25% of SEP, 47% of EMG and 31% of EEG. There were no significant differences among various types (P 〉 0.05). ② Results of CSF-lg test: There were no significant differences among various types (P 〉 0.05); however, abnormalities in experimental group was higher than those in control group (P 〈 0.01). CONCLUSION : Results of follow-up study suggest that improvement of clinical symptom is earlier than neuroelectrophysiological recovery; MCV and EMG recoveries are faster than that of NCV; the earlier the abnormality of EMG, the poorer the recovery. CSF4g recovers normally along improvement of clinical symptoms. It is of significance for neuroelectrophysiology and abnormality of CSF-Ig to determine degree of peripheral nerve demyelination and prognosis.