Objective:Red blood cell distribution width(RDW)has been utilized as a prognostic indicator for mortality risk assessment in cardiovascular and cerebrovascular patients.Nevertheless,the prognostic significance of RDW ...Objective:Red blood cell distribution width(RDW)has been utilized as a prognostic indicator for mortality risk assessment in cardiovascular and cerebrovascular patients.Nevertheless,the prognostic significance of RDW in critically ill patients with cerebral infarction is yet to be investigated.The objective of this study is to examine the association between RDW and the risk of all-cause mortality in cerebral infarction patients admitted to the intensive care unit(ICU).Method:A retrospective cohort study was conducted using the Medical Information Mart for Intensive Care IV 2.2(MIMIC-IV)intensive care dataset for data analysis.The main results were the all-cause mortality rates at 3 and 12 months of follow-up.Cumulative curves were plotted using the Kaplan-Meier method,and Cox proportional hazards analysis was used to examine the relationship between RDW and mortality rates in critically ill cerebral infarction patients.Results:The findings indicate that RDW serves as a significant prognostic factor for mortality risk in critically ill stroke patients,specifically at the 3 and 12-month follow-up periods.The observed correlation between increasing RDW levels and higher mortality rates among cerebral infarction patients further supports the potential utility of RDW as a predictive indicator.Conclusion:RDW emerges as an independent predictor of mortality risk during the 3 and 12-month follow-up periods for critically ill patients with cerebral infarction.展开更多
Terrain texture analysis is an important method of digital terrain analysis in quantitative geomorphological research and in the exploration of the spatial heterogeneity and autocorrelation of terrain features. Howeve...Terrain texture analysis is an important method of digital terrain analysis in quantitative geomorphological research and in the exploration of the spatial heterogeneity and autocorrelation of terrain features. However, a major issue often neglected in previous studies is the calculation unit of the terrain texture, that is, the stability analysis unit. As the test size increases, the derived terrain textures become increasingly similar so that their differences can be ignored. The test size of terrain texture is defined as the stability analysis unit. This study randomly selected 48 areas within the Loess Plateau in northern Shaanxi in China as the study sites and used the gray level co-occurrence matrix to calculate the terrain texture. The stability analysis unit of the terrain texture was then extracted, and its spatial distribution pattern in the Loess Plateau was studiedusing spatial interpolation method. Four terrain texture metrics, i.e., homogeneity, energy, correlation, and contrast, were extracted on the basis of the stability analysis unit, and the spatial variation patterns of these parameters were studied. Results showed that the spatial distribution pattern and the terrain texture metrics reflected a trend of high–low–high from north to south, which correlated with the spatial distribution of the landforms at the Loess Plateau. In addition, the terrain texture measures was significantly correlated with the terrain factors of gully density and slope, and this relationship showed that terrain texture measures based on the stability analysis unit could reflect the basic characteristics of terrain morphology. The stability analysis unit provided a reasonable analytical scale for terrain texture analysis and could be used as a measure of the regional topography to accurately describe basic terrain characteristics.展开更多
Symptoms of dental fluorosis such as mottled teeth are common among adults, youth and children in several rural communities in northern Nigeria. This has inspired the Authors to investigate the concentration of fluori...Symptoms of dental fluorosis such as mottled teeth are common among adults, youth and children in several rural communities in northern Nigeria. This has inspired the Authors to investigate the concentration of fluoride in the natural water systems of the major aquifer units (Basement, Sedimentary, Volcanic and Younger Granites) in some parts of northern Nigeria and to delineate areas of high risk of dental fluorosis, crippling skeletal fluorosis and dental caries. Six hundred and twenty seven analytical values for water were obtained from the literature and from analysis of samples from the major aquifer units of northern Nigeria: Basement-232, Sedimentary-328, Younger Granites-38 and Volcanic-28. Fluoride concentrations range from 0.03 to 10.30 mg/L in the Basement Aquifer;0.00 to 5.00 mg/L in the Sedimentary Aquifer;0.00 to 0.89 mg/L in the Younger Granites Aquifer;and 0.00 to 0.78 mg/L in the Volcanic Aquifer. A background value of 1.0 mg/L for fluoride concentration for northern Nigeria has been determined in this study. Areas identified with high fluoride in their waters above the World Health Organisation (WHO) recommended maximum permissible level in drinking water of 1.5 mg/L are: Dzuma, Dilchidima, Ngalbi, Udin, Kaltungo Biliri, Shongwom, Dass in the the northeast basement aquifers;Maiduguri, Mafa, Mobbar, Ngala, Logomani, Gombe in the northeast sedimentary aquifers: Langtang, Dorong, Furzi in the north-central basement aquifers and Pakoro in the northcentral sedimentary aquifers: Shawo and Barkin Lamba in the northwest basement aquifers. No anomalously high values of fluoride were recorded in the northwest sedimentary aquifers. All waters sampled in the Younger Granites and the Volcanic Aquifers have fluoride contents lower than the WHO recommended maximum permissible level in drinking water of 1.5 mg/L;and over ninety percent of the waters have fluoride concentration below the 0.5 mg/L recommended by WHO for the prevention of dental caries. Positive correlation between dental fluorosis and high fluoride water consumption has been established in all the areas with high fluoride in their waters. Positive correlation has also been established between genu valgum (bowing of legs) and consumption of high fluo-ride waters in Langtang Area. These data have been used to delineate areas of the Younger Granites Province and the Volcanic Province where inhabitants are at high risk of having dental caries.展开更多
Aiming at that the successive test data set of the strapdown inertial measurement unit is always small,a Bayesian method is used to study its statistical characteristics.Its prior and posterior distributions are set u...Aiming at that the successive test data set of the strapdown inertial measurement unit is always small,a Bayesian method is used to study its statistical characteristics.Its prior and posterior distributions are set up by the method and the pretest,sample and population information.Some statistical inferences can be made based on the posterior distribution.It can reduce the statistical analysis error in the case of small sample set.展开更多
Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this...Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this continuous changes in generation condition, the fault current level in network will be affected, this changes in fault current level will affect in the coordination between protection relays and to keep the coordination at right way, an adaptive protection system is required that can adaptive its setting according to generation changes, the fault current level in each case is evaluated using ETAP software, and the required relay setting in each case is also evaluated using Grey Wolf Optimizer (GWO) algorithm, and to select suitable setting which required in each condition, to select the active setting group of protection relay according to generation capacity, central protection unite can be used, and to improve protection stability and minimizing relays tripping time, a proposed method for selecting suitable backup relay is used, which leads to decrease relays tripping time and increase system stability, output settings for relays in all cases achieved our constrains.展开更多
This paper presents the design proposal of distribution network monitoring unit based on dual-DSP.A detailed description of the hardware structure about the device is introduced which including signal scheduling,SPI c...This paper presents the design proposal of distribution network monitoring unit based on dual-DSP.A detailed description of the hardware structure about the device is introduced which including signal scheduling,SPI communication,the serial human-computer communication and network communication.Additionally,the paper describes the software process about the master and slave DSPs.Then the analog precision test and the protection response test are carried out.The result shows that the design proposal is correct.展开更多
A remote antenna unit （RAU） selection model is presented, and two kinds of handoffs, intra-cell handoff （HO） and inter-cell HO, are defined in distributed mobile communications systems （DAS）. After that, an inte...A remote antenna unit （RAU） selection model is presented, and two kinds of handoffs, intra-cell handoff （HO） and inter-cell HO, are defined in distributed mobile communications systems （DAS）. After that, an inter-cell HO model is proposed, in which the average power of the active set （AS） is used to predict the position of the mobile station （MS）. The total power of the AS and the handoff set （HOS） are utilized to determine whether an inter-cell HO is necessary. Furthermore, the relationship between HO parameters and performance metrics is studied in detail based on RAU selection. Simulation results show that both the intra-cell HO and the inter-cell HO can achieve oerfect performance by aoprooriate settings of HO parameters.展开更多
The theory of three-dimensional deformation is used.Based on rigid plastic assumption, the theory of stick friction and the sheet crown curve at the entry and the exit are used. The mathematical analytical formula of ...The theory of three-dimensional deformation is used.Based on rigid plastic assumption, the theory of stick friction and the sheet crown curve at the entry and the exit are used. The mathematical analytical formula of the rolling force in lateral distribution is deriven.展开更多
This study was conducted to identify the number and density of active licensed acupuncturists(LAcs),as well as the number of accredited schools in acupuncture and Oriental medicine(AOM),as of January 1,2023,in the Uni...This study was conducted to identify the number and density of active licensed acupuncturists(LAcs),as well as the number of accredited schools in acupuncture and Oriental medicine(AOM),as of January 1,2023,in the United States(U.S.).The number of active LAcs as of January 1,2023 was 34,524,potentially33,364 after removing license duplication in multiple states,among which the largest three states were California(with 7317 LAcs[21.19%of the total]),New York(5024[14.55%])and Florida(2644[7.66%]).The total number of LAcs decreased by 8.87%from 2018,and fell short of our projected number of LAcs in 2023 by 9037,or 20.75%.The overall LAc density in the U.S.Dmeasured as the number of LAcs per 100,000 populationDwas 10.36,less than in 2018.There were 56 active,accredited AOM schools which offered a total of 147 programs(121 at the level necessary for licensing[entry-level],12 for an advanced practicing degree[advanced-level],and 14 for certifications).Broken down further,offerings included 50 master's degrees in acupuncture,40 master's degrees in Oriental medicine,31 entry-level doctorate degrees(10 in acupuncture and 21 in acupuncture plus Chinese herbal medicine),and 12advanced-level doctorate degrees in AOM.The certification programs included one in East-Asian Medical Bodywork and 13 in CHM.Among these schools in 2023,institutions in the West and East Coast states comprised 67.86%(decreased from 77.42%in 2018)of the national total.California,Florida and Illinois represented 39.29%.There were 48 jurisdictions with acupuncture practice laws in place.The data suggests that the acupuncture profession in the U.S.has been significantly impacted during the coronavirus disease 2019 pandemic.展开更多
A full distribution CNC system based on SERCOS bus is studied in accordance with the limitations of traditional PC-based motion card. The conventional PC-based motion control card is dispersed into several autonomous ...A full distribution CNC system based on SERCOS bus is studied in accordance with the limitations of traditional PC-based motion card. The conventional PC-based motion control card is dispersed into several autonomous intelligent servo-control units with the function of servo driver. The autonomous intelligent servocontrol units realize the loop control of position, velocity and current. Interpolation computation is completed in PC and the computational results are transferred to every autonomous intelligent servo-control unit by high speed SERCOS bus. Software or hardware synchronization technology is used to ensure all servomotors are successive and synchronously running. The communication and synchronization technology of SERCOS are also researched and the autonomous intelligent servo-control card is developed byself. Finally, the experiment of circle contour process on a prototype system proves the feasibility.展开更多
The distribution of the Jurassic coal measures in the northern Qaidam Basin is obviously controlled by the regional structures. Based on the existing data of coalfield exploration and combined with the analysis of coa...The distribution of the Jurassic coal measures in the northern Qaidam Basin is obviously controlled by the regional structures. Based on the existing data of coalfield exploration and combined with the analysis of coalfield basement structures, features of the main faults, and the distribution of coal measures, this paper brings forward a scheme of coalfield tectonic divisional units and the definition of the coal-controlling structural styles in the northern Qaidam Basin. The structure control of the distribution of coal measures is further discussed. Several stages of regional tectonic activities since the Indosinian has led to the distribution of coal measures into the characteristics of zonation from the north to south and block from east to west. The results indicate that the structural deformations are the most intense in the front of the three uplifted belts, which are characterized by the combination of thrusts. The coal measures are uplifted to the shallow formations, and are easy to be exploited, but the scale of mines is small because of serious damages by the coal distribution. On the contrary, the stress and strain are weak in the three depressions, with the coal-controlling structural styles being mainly the thrust-fold and thrust-monocline combinations. The distribution of coals in the depressions is relatively stable. The shallower part of the depression will become the key areas for exploration and development of coal resources in the northern Qaidam Basin.展开更多
AIM: To compare the racial differences of anatomical distribution of colorectal cancer (CRC) and determine the association of age, gender and time with anatomical distribution between patients from America (white) and...AIM: To compare the racial differences of anatomical distribution of colorectal cancer (CRC) and determine the association of age, gender and time with anatomical distribution between patients from America (white) and China (oriental).METHODS: Data was collected from 690 consecutive patients in Cleveland Clinic Florida, U.S.A. and 870consecutive patients in Nan Fang Hospital affiliated to the First Military Medical University, China over the past 11years from 1990 to 2000. All patients had colorectal adenocarcinoma diagnosed by histology and underwent surgery.RESULTS: The anatomical subsite distribution of tumor,age and gender were significantly different between white and oriental patients. Lesions in the proximal colon (P＜0.001) were found in 36.3 % of white vs 26.0 % of oriental patients and cancers located in the distal colon and rectum in 63.7 % of white and 74 % of oriental patients (P＜0.001). There was a trend towards the redistribution from distal colon and rectum to proximal colon in white males over time, especially in older patients (＞80 years).No significant change of anatomical distribution occurred in white women and Oriental patients. The mean age at diagnosis was 69.0 years in white patients and 48.3 years in Oriental patients (P＜0.001).CONCLUSION: This is the first study comparing the anatomical distribution of colorectal cancers in whites and Chinese patients. White Americans have a higher risk of proximal CRC and this risk increased with time. The proportion of white males with CRC also increased with time.Chinese patients were more likely to have distal CRC and developed the disease at a significantly earlier age than white patients. These findings have enhanced our understanding of the disease process of colorectal cancer in these two races.展开更多
The main spatial distribution features of shear rate in a stirred tank operated with five different radial and axial flow impellers were presented with particle image velocimetry(PIV)experiments.Not only the average s...The main spatial distribution features of shear rate in a stirred tank operated with five different radial and axial flow impellers were presented with particle image velocimetry(PIV)experiments.Not only the average shear rate in the whole tank but also the local value in the vicinity of impeller increases linearly with impeller speed.Furthermore,the shear coefficient(Ks,imp)at the impeller outlet is linearly related to the impeller flow number(Nq)and decreases with the increase of Nq in general at the constant power consumption per unit volume(Pv).During scale-up based on the constant Pv and geometric similarity,CFD results show that the volume-averaged shear rate(cavg)for RDT decreases faster than that of other impellers with the impeller tip velocity(Utip).The novel multi-blade combined(MBC)impeller with the increased height-to-diameter ratio of the stirred tank is able to more effectively improve the distribution uniformity of shear rate at the same Pv after scale-up.These studies provide a data basis for selecting the impeller types and improving the shear rate environment in the large-scale stirred tank.展开更多
We investigated the spatio-temporal and environmental factors that affect the distribution and abundance of wintering anchovy and quantifi es the infl uences of these factors. Generalized additive models(GAMs) were de...We investigated the spatio-temporal and environmental factors that affect the distribution and abundance of wintering anchovy and quantifi es the infl uences of these factors. Generalized additive models(GAMs) were developed to examine the variation in species distribution and abundance with a set of spatiotemporal and oceanographic factors, using data collected by bottom trawl surveys and remote sensing in the central and southern Yellow Sea during 2000–2011. The fi nal model accounted for 28.21% and 41.03% of the variance in anchovy distribution and abundance, respectively. The results of a two-step GAM showed that hour, longitude, latitude, temperature gradient(TGR), and chlorophyll a(Chl- a) concentration best explained the anchovy distribution(presence/absence) and that a model including year, longitude, latitude, depth, sea surface temperature(SST), and TGR best described anchovy abundance(given presence). Longitude and latitude were the most important factors affecting both distribution and abundance, but the area of high abundance tended to be east and south of the area where anchovy were most likely to be present. Hour had a signifi cant effect on distribution, but year was more important for anchovy abundance, indicating that the anchovy catch ratio varied across the day but abundance had an apparent interannual variation. With respect to environmental factors, TGR and Chl- a concentration had effects on distribution, while depth, SST, and TGR affected abundance. Changes in SST between two successive years or between any year and the 2000–2011 mean were not associated with changes in anchovy distribution or abundance. This fi nding indicated that short- and long-term water temperature changes during 2000–2011 were not of suffi cient magnitude to give rise to variation in wintering anchovy distribution or abundance in the study area. The results of this study have important implications for fi sheries management.展开更多
Self-driving and semi-self-driving cars play an important role in our daily lives.The effectiveness of these cars is based heavily on the use of their surrounding areas to collect sensitive and vital information.Howev...Self-driving and semi-self-driving cars play an important role in our daily lives.The effectiveness of these cars is based heavily on the use of their surrounding areas to collect sensitive and vital information.However,external infrastructures also play significant roles in the transmission and reception of control data,cooperative awareness messages,and caution notifications.In this case,roadside units are considered one of themost important communication peripherals.Random distribution of these infrastructures will overburden the spread of self-driving vehicles in terms of cost,bandwidth,connectivity,and radio coverage area.In this paper,a new distributed roadside unit is proposed to enhance the performance and connectivity of these cars.Therefore,this approach is based primarily on k-means to find the optimal location of each roadside unit.In addition,this approach supports dynamicmobility with a long period of connectivity for each car.Further,this system can adapt to various locations(e.g.,highways,rural areas,urban environments).The simulation results of the proposed system are reflected in its efficiency and effectively.Thus,the system can achieve a high connectivity rate with a low error rate while reducing costs.展开更多
Based on the property that carboxymethylcellulose (CMC ) can be de-graded to anhydroglucose residues by cellulase, the rate constant (K) of enzymatic degra-dation of CMC synthesized in the benzene-ethanol medium has b...Based on the property that carboxymethylcellulose (CMC ) can be de-graded to anhydroglucose residues by cellulase, the rate constant (K) of enzymatic degra-dation of CMC synthesized in the benzene-ethanol medium has been determined. Further-morel experimental equation K = 2.71× 10^(-2)(DS)^(-1.2) reflecting the relationship betweenK and the degree of substitution (DS) is correlated and used to describe chemical mi-crostructure uniformity of the distribution of substituents along chains effectively. Chainstructure parameters of enzymatic degradation products of CMC-the number of chainbreaks and the percentage of glucose released have been also measured. Average length ofsubstituted and unsubstituted chain segments are calculated simultaneously. Through thestudy of static and dynamic procedures of enzymatic degradation, the method to charac-terize the distribution of substituents of CMC along the chain has been improved.展开更多
In this paper we study the problem of explicit representation and convergence of Pal type （0;1） interpolation and its converse, with some additional conditions, on the non-uniformly distributed nodes on the unit cir...In this paper we study the problem of explicit representation and convergence of Pal type （0;1） interpolation and its converse, with some additional conditions, on the non-uniformly distributed nodes on the unit circle obtaIned by projecting the interlaced zeros of Pn （x） and Pn′ （x） on the unit circle. The motivation to this problem can be traced to the recent studies on the regularity of Birkhoff interpolation and Pal type interpolations on non-uniformly distributed zeros on the unit circle.展开更多
A three-dimensional contact model of 1×7 steel strand was established. Contact point was searched by Splitting-pinball algorithm, and Augmented-Lagrangian algorithm was applied for analysis of contact loads. The ...A three-dimensional contact model of 1×7 steel strand was established. Contact point was searched by Splitting-pinball algorithm, and Augmented-Lagrangian algorithm was applied for analysis of contact loads. The exerted tensile loads to the model were analyzed using finite element method. After analyzing calculation results, the laws of steel wire stress distribution in axis direction and in its cross-section were found. Friction coefficients were set as 0.10, 0.11, and 0.12, respec- tively, to obtain the influence law of friction coefficient to steel wire stresses. Research result shows that friction coefficient has significant influence on the shear stress of steel wire. Analyzed the calculation results of steel strand with five different lay pitch multiples and got the influence law of lay pitch multiple to the stresses of steel wire in steel strand. The Von Misses stress of steel wire increases following with the increasing of lay pitches nmltiples, but the increment value is not very prominent. The shear stress of steel wire decreases following the increase of lay pitch multiple, and the changing amplitude is large when lay pitch multiple is small. Finally, carried out a steel strand tensile deformation test and the consistency of test results with the calculation results shows that the selected model is reasonable.展开更多
The rapid spreading of the Photovoltaic (PV) Systems as Distributed Generation (DG) in medium and low voltage networks created many effects and changes on the existing power system networks. In this work, two methods ...The rapid spreading of the Photovoltaic (PV) Systems as Distributed Generation (DG) in medium and low voltage networks created many effects and changes on the existing power system networks. In this work, two methods have been used and applied to determine the optimal allocation and sizing of the PV to be installed as DGs (ranging from 250 kW up to 3 MW). The first one is to determine the location according to the maximal power losses reduction over the feeder. The second one is by using the Harmony Search Algorithm which is claimed to be a powerful technique for optimal allocation of PV systems. The results of the two techniques were compared and found to be nearly closed. Furthermore, investigation on the effects on the feeder in terms of voltage levels, power factor readings, and short circuit current levels has been done. All calculations and simulations are conducted by using the MATLAB Simulation Program. Some field calculations and observations have been expended in order to substantiate the research findings and validation.展开更多
基金Project of Science and Technology Plan of Tianjin City(Grant number 20ZYJDSY00020)。
文摘Objective:Red blood cell distribution width(RDW)has been utilized as a prognostic indicator for mortality risk assessment in cardiovascular and cerebrovascular patients.Nevertheless,the prognostic significance of RDW in critically ill patients with cerebral infarction is yet to be investigated.The objective of this study is to examine the association between RDW and the risk of all-cause mortality in cerebral infarction patients admitted to the intensive care unit(ICU).Method:A retrospective cohort study was conducted using the Medical Information Mart for Intensive Care IV 2.2(MIMIC-IV)intensive care dataset for data analysis.The main results were the all-cause mortality rates at 3 and 12 months of follow-up.Cumulative curves were plotted using the Kaplan-Meier method,and Cox proportional hazards analysis was used to examine the relationship between RDW and mortality rates in critically ill cerebral infarction patients.Results:The findings indicate that RDW serves as a significant prognostic factor for mortality risk in critically ill stroke patients,specifically at the 3 and 12-month follow-up periods.The observed correlation between increasing RDW levels and higher mortality rates among cerebral infarction patients further supports the potential utility of RDW as a predictive indicator.Conclusion:RDW emerges as an independent predictor of mortality risk during the 3 and 12-month follow-up periods for critically ill patients with cerebral infarction.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41471316, 41571383, 41671389)the Priority Academic Program Development of Jiangsu Higher Education Institutions-PAPD (Grant No. 164320H101)the Key Project of Natural Science Research of Anhui Provincial Department of Education (Grant No. KJ2015A171)
文摘Terrain texture analysis is an important method of digital terrain analysis in quantitative geomorphological research and in the exploration of the spatial heterogeneity and autocorrelation of terrain features. However, a major issue often neglected in previous studies is the calculation unit of the terrain texture, that is, the stability analysis unit. As the test size increases, the derived terrain textures become increasingly similar so that their differences can be ignored. The test size of terrain texture is defined as the stability analysis unit. This study randomly selected 48 areas within the Loess Plateau in northern Shaanxi in China as the study sites and used the gray level co-occurrence matrix to calculate the terrain texture. The stability analysis unit of the terrain texture was then extracted, and its spatial distribution pattern in the Loess Plateau was studiedusing spatial interpolation method. Four terrain texture metrics, i.e., homogeneity, energy, correlation, and contrast, were extracted on the basis of the stability analysis unit, and the spatial variation patterns of these parameters were studied. Results showed that the spatial distribution pattern and the terrain texture metrics reflected a trend of high–low–high from north to south, which correlated with the spatial distribution of the landforms at the Loess Plateau. In addition, the terrain texture measures was significantly correlated with the terrain factors of gully density and slope, and this relationship showed that terrain texture measures based on the stability analysis unit could reflect the basic characteristics of terrain morphology. The stability analysis unit provided a reasonable analytical scale for terrain texture analysis and could be used as a measure of the regional topography to accurately describe basic terrain characteristics.
文摘Symptoms of dental fluorosis such as mottled teeth are common among adults, youth and children in several rural communities in northern Nigeria. This has inspired the Authors to investigate the concentration of fluoride in the natural water systems of the major aquifer units (Basement, Sedimentary, Volcanic and Younger Granites) in some parts of northern Nigeria and to delineate areas of high risk of dental fluorosis, crippling skeletal fluorosis and dental caries. Six hundred and twenty seven analytical values for water were obtained from the literature and from analysis of samples from the major aquifer units of northern Nigeria: Basement-232, Sedimentary-328, Younger Granites-38 and Volcanic-28. Fluoride concentrations range from 0.03 to 10.30 mg/L in the Basement Aquifer;0.00 to 5.00 mg/L in the Sedimentary Aquifer;0.00 to 0.89 mg/L in the Younger Granites Aquifer;and 0.00 to 0.78 mg/L in the Volcanic Aquifer. A background value of 1.0 mg/L for fluoride concentration for northern Nigeria has been determined in this study. Areas identified with high fluoride in their waters above the World Health Organisation (WHO) recommended maximum permissible level in drinking water of 1.5 mg/L are: Dzuma, Dilchidima, Ngalbi, Udin, Kaltungo Biliri, Shongwom, Dass in the the northeast basement aquifers;Maiduguri, Mafa, Mobbar, Ngala, Logomani, Gombe in the northeast sedimentary aquifers: Langtang, Dorong, Furzi in the north-central basement aquifers and Pakoro in the northcentral sedimentary aquifers: Shawo and Barkin Lamba in the northwest basement aquifers. No anomalously high values of fluoride were recorded in the northwest sedimentary aquifers. All waters sampled in the Younger Granites and the Volcanic Aquifers have fluoride contents lower than the WHO recommended maximum permissible level in drinking water of 1.5 mg/L;and over ninety percent of the waters have fluoride concentration below the 0.5 mg/L recommended by WHO for the prevention of dental caries. Positive correlation between dental fluorosis and high fluoride water consumption has been established in all the areas with high fluoride in their waters. Positive correlation has also been established between genu valgum (bowing of legs) and consumption of high fluo-ride waters in Langtang Area. These data have been used to delineate areas of the Younger Granites Province and the Volcanic Province where inhabitants are at high risk of having dental caries.
文摘Aiming at that the successive test data set of the strapdown inertial measurement unit is always small,a Bayesian method is used to study its statistical characteristics.Its prior and posterior distributions are set up by the method and the pretest,sample and population information.Some statistical inferences can be made based on the posterior distribution.It can reduce the statistical analysis error in the case of small sample set.
文摘Distributed generators now is widely used in electrical power networks, in some cases it works seasonally, and some types works at special weather conditions like photo voltaic systems and wind energy, and due to this continuous changes in generation condition, the fault current level in network will be affected, this changes in fault current level will affect in the coordination between protection relays and to keep the coordination at right way, an adaptive protection system is required that can adaptive its setting according to generation changes, the fault current level in each case is evaluated using ETAP software, and the required relay setting in each case is also evaluated using Grey Wolf Optimizer (GWO) algorithm, and to select suitable setting which required in each condition, to select the active setting group of protection relay according to generation capacity, central protection unite can be used, and to improve protection stability and minimizing relays tripping time, a proposed method for selecting suitable backup relay is used, which leads to decrease relays tripping time and increase system stability, output settings for relays in all cases achieved our constrains.
文摘This paper presents the design proposal of distribution network monitoring unit based on dual-DSP.A detailed description of the hardware structure about the device is introduced which including signal scheduling,SPI communication,the serial human-computer communication and network communication.Additionally,the paper describes the software process about the master and slave DSPs.Then the analog precision test and the protection response test are carried out.The result shows that the design proposal is correct.
基金The National Natural Science Foundation of China(No60496311)
文摘A remote antenna unit （RAU） selection model is presented, and two kinds of handoffs, intra-cell handoff （HO） and inter-cell HO, are defined in distributed mobile communications systems （DAS）. After that, an inter-cell HO model is proposed, in which the average power of the active set （AS） is used to predict the position of the mobile station （MS）. The total power of the AS and the handoff set （HOS） are utilized to determine whether an inter-cell HO is necessary. Furthermore, the relationship between HO parameters and performance metrics is studied in detail based on RAU selection. Simulation results show that both the intra-cell HO and the inter-cell HO can achieve oerfect performance by aoprooriate settings of HO parameters.
文摘The theory of three-dimensional deformation is used.Based on rigid plastic assumption, the theory of stick friction and the sheet crown curve at the entry and the exit are used. The mathematical analytical formula of the rolling force in lateral distribution is deriven.
文摘This study was conducted to identify the number and density of active licensed acupuncturists(LAcs),as well as the number of accredited schools in acupuncture and Oriental medicine(AOM),as of January 1,2023,in the United States(U.S.).The number of active LAcs as of January 1,2023 was 34,524,potentially33,364 after removing license duplication in multiple states,among which the largest three states were California(with 7317 LAcs[21.19%of the total]),New York(5024[14.55%])and Florida(2644[7.66%]).The total number of LAcs decreased by 8.87%from 2018,and fell short of our projected number of LAcs in 2023 by 9037,or 20.75%.The overall LAc density in the U.S.Dmeasured as the number of LAcs per 100,000 populationDwas 10.36,less than in 2018.There were 56 active,accredited AOM schools which offered a total of 147 programs(121 at the level necessary for licensing[entry-level],12 for an advanced practicing degree[advanced-level],and 14 for certifications).Broken down further,offerings included 50 master's degrees in acupuncture,40 master's degrees in Oriental medicine,31 entry-level doctorate degrees(10 in acupuncture and 21 in acupuncture plus Chinese herbal medicine),and 12advanced-level doctorate degrees in AOM.The certification programs included one in East-Asian Medical Bodywork and 13 in CHM.Among these schools in 2023,institutions in the West and East Coast states comprised 67.86%(decreased from 77.42%in 2018)of the national total.California,Florida and Illinois represented 39.29%.There were 48 jurisdictions with acupuncture practice laws in place.The data suggests that the acupuncture profession in the U.S.has been significantly impacted during the coronavirus disease 2019 pandemic.
文摘A full distribution CNC system based on SERCOS bus is studied in accordance with the limitations of traditional PC-based motion card. The conventional PC-based motion control card is dispersed into several autonomous intelligent servo-control units with the function of servo driver. The autonomous intelligent servocontrol units realize the loop control of position, velocity and current. Interpolation computation is completed in PC and the computational results are transferred to every autonomous intelligent servo-control unit by high speed SERCOS bus. Software or hardware synchronization technology is used to ensure all servomotors are successive and synchronously running. The communication and synchronization technology of SERCOS are also researched and the autonomous intelligent servo-control card is developed byself. Finally, the experiment of circle contour process on a prototype system proves the feasibility.
文摘The distribution of the Jurassic coal measures in the northern Qaidam Basin is obviously controlled by the regional structures. Based on the existing data of coalfield exploration and combined with the analysis of coalfield basement structures, features of the main faults, and the distribution of coal measures, this paper brings forward a scheme of coalfield tectonic divisional units and the definition of the coal-controlling structural styles in the northern Qaidam Basin. The structure control of the distribution of coal measures is further discussed. Several stages of regional tectonic activities since the Indosinian has led to the distribution of coal measures into the characteristics of zonation from the north to south and block from east to west. The results indicate that the structural deformations are the most intense in the front of the three uplifted belts, which are characterized by the combination of thrusts. The coal measures are uplifted to the shallow formations, and are easy to be exploited, but the scale of mines is small because of serious damages by the coal distribution. On the contrary, the stress and strain are weak in the three depressions, with the coal-controlling structural styles being mainly the thrust-fold and thrust-monocline combinations. The distribution of coals in the depressions is relatively stable. The shallower part of the depression will become the key areas for exploration and development of coal resources in the northern Qaidam Basin.
文摘AIM: To compare the racial differences of anatomical distribution of colorectal cancer (CRC) and determine the association of age, gender and time with anatomical distribution between patients from America (white) and China (oriental).METHODS: Data was collected from 690 consecutive patients in Cleveland Clinic Florida, U.S.A. and 870consecutive patients in Nan Fang Hospital affiliated to the First Military Medical University, China over the past 11years from 1990 to 2000. All patients had colorectal adenocarcinoma diagnosed by histology and underwent surgery.RESULTS: The anatomical subsite distribution of tumor,age and gender were significantly different between white and oriental patients. Lesions in the proximal colon (P＜0.001) were found in 36.3 % of white vs 26.0 % of oriental patients and cancers located in the distal colon and rectum in 63.7 % of white and 74 % of oriental patients (P＜0.001). There was a trend towards the redistribution from distal colon and rectum to proximal colon in white males over time, especially in older patients (＞80 years).No significant change of anatomical distribution occurred in white women and Oriental patients. The mean age at diagnosis was 69.0 years in white patients and 48.3 years in Oriental patients (P＜0.001).CONCLUSION: This is the first study comparing the anatomical distribution of colorectal cancers in whites and Chinese patients. White Americans have a higher risk of proximal CRC and this risk increased with time. The proportion of white males with CRC also increased with time.Chinese patients were more likely to have distal CRC and developed the disease at a significantly earlier age than white patients. These findings have enhanced our understanding of the disease process of colorectal cancer in these two races.
基金National Key Research and Development Program (2020YFA0906800)the National Natural Science Foundation of China (21808221, 91934301, 21961160745)+2 种基金External Cooperation Program of BIC, Chinese Academy of Sciences (122111KYSB20190032)the Key Research Program of Nanjing IPE Institute of Green Manufacturing Industry (No. E0010719)Innovation Academy for Green Manufacture, Chinese Academy of Sciences (IAGM2020C06)
文摘The main spatial distribution features of shear rate in a stirred tank operated with five different radial and axial flow impellers were presented with particle image velocimetry(PIV)experiments.Not only the average shear rate in the whole tank but also the local value in the vicinity of impeller increases linearly with impeller speed.Furthermore,the shear coefficient(Ks,imp)at the impeller outlet is linearly related to the impeller flow number(Nq)and decreases with the increase of Nq in general at the constant power consumption per unit volume(Pv).During scale-up based on the constant Pv and geometric similarity,CFD results show that the volume-averaged shear rate(cavg)for RDT decreases faster than that of other impellers with the impeller tip velocity(Utip).The novel multi-blade combined(MBC)impeller with the increased height-to-diameter ratio of the stirred tank is able to more effectively improve the distribution uniformity of shear rate at the same Pv after scale-up.These studies provide a data basis for selecting the impeller types and improving the shear rate environment in the large-scale stirred tank.
基金Supported by the National Basic Research Program of China(973 Program)(No.2011CB409805)the National Special Research Fund for Non-Profit Sector(Agriculture)(No.200903005)the Taishan Scholar Program of Shandong Province
文摘We investigated the spatio-temporal and environmental factors that affect the distribution and abundance of wintering anchovy and quantifi es the infl uences of these factors. Generalized additive models(GAMs) were developed to examine the variation in species distribution and abundance with a set of spatiotemporal and oceanographic factors, using data collected by bottom trawl surveys and remote sensing in the central and southern Yellow Sea during 2000–2011. The fi nal model accounted for 28.21% and 41.03% of the variance in anchovy distribution and abundance, respectively. The results of a two-step GAM showed that hour, longitude, latitude, temperature gradient(TGR), and chlorophyll a(Chl- a) concentration best explained the anchovy distribution(presence/absence) and that a model including year, longitude, latitude, depth, sea surface temperature(SST), and TGR best described anchovy abundance(given presence). Longitude and latitude were the most important factors affecting both distribution and abundance, but the area of high abundance tended to be east and south of the area where anchovy were most likely to be present. Hour had a signifi cant effect on distribution, but year was more important for anchovy abundance, indicating that the anchovy catch ratio varied across the day but abundance had an apparent interannual variation. With respect to environmental factors, TGR and Chl- a concentration had effects on distribution, while depth, SST, and TGR affected abundance. Changes in SST between two successive years or between any year and the 2000–2011 mean were not associated with changes in anchovy distribution or abundance. This fi nding indicated that short- and long-term water temperature changes during 2000–2011 were not of suffi cient magnitude to give rise to variation in wintering anchovy distribution or abundance in the study area. The results of this study have important implications for fi sheries management.
文摘Self-driving and semi-self-driving cars play an important role in our daily lives.The effectiveness of these cars is based heavily on the use of their surrounding areas to collect sensitive and vital information.However,external infrastructures also play significant roles in the transmission and reception of control data,cooperative awareness messages,and caution notifications.In this case,roadside units are considered one of themost important communication peripherals.Random distribution of these infrastructures will overburden the spread of self-driving vehicles in terms of cost,bandwidth,connectivity,and radio coverage area.In this paper,a new distributed roadside unit is proposed to enhance the performance and connectivity of these cars.Therefore,this approach is based primarily on k-means to find the optimal location of each roadside unit.In addition,this approach supports dynamicmobility with a long period of connectivity for each car.Further,this system can adapt to various locations(e.g.,highways,rural areas,urban environments).The simulation results of the proposed system are reflected in its efficiency and effectively.Thus,the system can achieve a high connectivity rate with a low error rate while reducing costs.
基金Supported by National Natural Science Foundation of China （61164013, U1334211, 51174091）, the Key Program of China Ministry of Railway （2011Z002-D）, and Natural Science Foundation of Jiangxi Province （20122BAB201021）
文摘Based on the property that carboxymethylcellulose (CMC ) can be de-graded to anhydroglucose residues by cellulase, the rate constant (K) of enzymatic degra-dation of CMC synthesized in the benzene-ethanol medium has been determined. Further-morel experimental equation K = 2.71× 10^(-2)(DS)^(-1.2) reflecting the relationship betweenK and the degree of substitution (DS) is correlated and used to describe chemical mi-crostructure uniformity of the distribution of substituents along chains effectively. Chainstructure parameters of enzymatic degradation products of CMC-the number of chainbreaks and the percentage of glucose released have been also measured. Average length ofsubstituted and unsubstituted chain segments are calculated simultaneously. Through thestudy of static and dynamic procedures of enzymatic degradation, the method to charac-terize the distribution of substituents of CMC along the chain has been improved.
文摘In this paper we study the problem of explicit representation and convergence of Pal type （0;1） interpolation and its converse, with some additional conditions, on the non-uniformly distributed nodes on the unit circle obtaIned by projecting the interlaced zeros of Pn （x） and Pn′ （x） on the unit circle. The motivation to this problem can be traced to the recent studies on the regularity of Birkhoff interpolation and Pal type interpolations on non-uniformly distributed zeros on the unit circle.
文摘A three-dimensional contact model of 1×7 steel strand was established. Contact point was searched by Splitting-pinball algorithm, and Augmented-Lagrangian algorithm was applied for analysis of contact loads. The exerted tensile loads to the model were analyzed using finite element method. After analyzing calculation results, the laws of steel wire stress distribution in axis direction and in its cross-section were found. Friction coefficients were set as 0.10, 0.11, and 0.12, respec- tively, to obtain the influence law of friction coefficient to steel wire stresses. Research result shows that friction coefficient has significant influence on the shear stress of steel wire. Analyzed the calculation results of steel strand with five different lay pitch multiples and got the influence law of lay pitch multiple to the stresses of steel wire in steel strand. The Von Misses stress of steel wire increases following with the increasing of lay pitches nmltiples, but the increment value is not very prominent. The shear stress of steel wire decreases following the increase of lay pitch multiple, and the changing amplitude is large when lay pitch multiple is small. Finally, carried out a steel strand tensile deformation test and the consistency of test results with the calculation results shows that the selected model is reasonable.
文摘The rapid spreading of the Photovoltaic (PV) Systems as Distributed Generation (DG) in medium and low voltage networks created many effects and changes on the existing power system networks. In this work, two methods have been used and applied to determine the optimal allocation and sizing of the PV to be installed as DGs (ranging from 250 kW up to 3 MW). The first one is to determine the location according to the maximal power losses reduction over the feeder. The second one is by using the Harmony Search Algorithm which is claimed to be a powerful technique for optimal allocation of PV systems. The results of the two techniques were compared and found to be nearly closed. Furthermore, investigation on the effects on the feeder in terms of voltage levels, power factor readings, and short circuit current levels has been done. All calculations and simulations are conducted by using the MATLAB Simulation Program. Some field calculations and observations have been expended in order to substantiate the research findings and validation.
