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Bacillary dysentery remains a public health concern in the world. Hunan Province is one of the provinces having the highest risk of bacillary dysentery in China, however, the spatial-temporal distribution, variation of bacillary dysentery and sensitivity to meteorological factors in there are unclear. In this paper, a Bayesian space-time hierarchical model (BSTHM) was used to detect space-time variation, and effects of meteorological factors between 2010 and 2015. The risk of bacillary dysentery showed apparent spatial-temporal heterogeneity. The highest risk occurred in the summer season. Economically undeveloped mountainous areas in the west and south of the province had the highest incidence rates. Twenty three (18.9%) and 20 (16.4%) counties were identified as hot and cold spots, respectively. Among the hotspots, 11 counties (47.8%) exhibited a rapidly decreasing trend, suggesting they may become low-risk areas in the future. Of the cold spot counties, six (30%) showed a slowly decreasing trend, and may have a higher risk in the future. Among meteorological factors, air temperature, relative humidity, and wind speed all played a significant role in the spatial-temporal distribution of bacillary dysentery risk. These findings can contribute to the implementation of an early warning system for controlling and preventing bacillary dysentery.

The commercial value of Kurles pears pericarp, a popular and favored fruit for its unique aroma and refreshingly crisp texture, had sharply decreased because of a rust breakout of the beloved pear in China during the atmosphere-controlled storage. High performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) were used to analyze rust spots on the pericarp of Kurle pears. Therefore, the chemical compounds of four various eluates, originating from the rust-colored substance collected from the pears pericarp effected, were identified successfully for the first time, which were just rhein, aloe-emodin, chrysophanol and emodin, respectively. Taken together with microstructure characteristics for rust-spots of Kurle pear pericarp, it was no doubt that these eluates were the main factors affecting the rust spots on the pericarp of the Kurle pears during the atmosphere-controlled storage, which was a sign and consequence resisting the undesirable stress of the external environment.

Hand, foot and mouth disease (HFMD) in children under the age of five is a major public health issue in China. Beijing–Tianjin–Hebei is the largest urban agglomeration in northern China. The present study aimed to analyze the epidemiological features of HFMD, reveal spatial clusters, and detect risk factors in this region. Reports of HFMD cases in Beijing–Tianjin–Hebei from 1 January 2013 to 31 December 2013 were collected from 211 counties or municipal districts. First, the epidemiological features were explored, and then SaTScan analysis was carried out to detect spatial clusters of HFMD. Finally, GeoDetector and spatial paneled model were used to identify potential risk factors among the socioeconomic and meteorological variables. There were a total of 90,527 HFMD cases in the year 2013. The highest rate was in individuals aged one year, with an incidence of 24.76/103. Boys (55,168) outnumbered girls (35,359). Temporally, the incidence rose rapidly from April, peaking in June (4.08/103). Temperature, relative humidity and wind speed were positively associated with the incidence rate, while precipitation and sunshine hours had a negative association. The explanatory powers of these factors were 57%, 13%, 2%, 21% and 12%, respectively. Spatially, the highest-risk regions were located in Beijing and neighboring areas, with a relative risk (RR) value of 3.04. The proportion of primary industry was negatively associated with HFMD transmission, with an explanatory power of 32%. Gross domestic product (GDP) per capita, proportion of tertiary industry, and population density were positively associated with disease incidence, with explanatory powers of 22%, 17% and 15%, respectively. These findings may be helpful in the risk assessment of HFMD transmission and for implementing effective interventions to reduce the burden of this disease.

Using a chemical probe mimic of vitamin B12, we reveal a light- and B12-dependent DNA regulator, and make the unexpected discovery of B12 having regulatory involvement in microbial folate, ubiquinone, and methionine processes. These findings suggest a pivotal role for B12 in the control of cell growth, which may lead to coordination of cell behavior in complex multicellular systems. As key research questions emerge from host-associated and environmental microbiomes, we anticipate that B12 regulatory control of metabolism will be found to be generalizable, will be critical for coordination of individual microbe and community metabolism, and that organismal interdependencies for B12 may be pertinent to microbiome organization, stability, and overall function.

Significance Using a chemical probe mimic of vitamin B 12 , we reveal a light- and B 12 -dependent DNA regulator, and make the unexpected discovery of B 12 having regulatory involvement in microbial folate, ubiquinone, and methionine processes. These findings suggest a pivotal role for B 12 in the control of cell growth, which may lead to coordination of cell behavior in complex multicellular systems. As key research questions emerge from host-associated and environmental microbiomes, we anticipate that B 12 regulatory control of metabolism will be found to be generalizable, will be critical for coordination of individual microbe and community metabolism, and that organismal interdependencies for B 12 may be pertinent to microbiome organization, stability, and overall function.

As a promising fault detection algorithm, Advanced Receiver Autonomous Integrity Monitoring (ARAIM) was widely researched by European Space Agency (ESA) and the Federal Aviation Administration (FAA). To meet the requirement of precision approach based on vertical navigation and to improve the availability of the ARAIM algorithm, the vertical protection limit (VPL) needed to be optimized. The false detection probability and the missed detection probability were the optimization parameters, and the VPL optimization problem was transformed into double-objective program problem, so the VPL model was established. For verifying the effectiveness of the optimization algorithm, GPS navigation data acquired by two observation stations were used to optimize the VPL. The results show that the optimal VPL is positively correlated with the number of visible stars, and the optimization efficiency is 10%.

With the rapid development of Global Navigation Satellite System (GNSS), receiver autonomous integrity monitoring (RAIM) has become an essential part of integrity monitoring of navigation satellite system. Conventional RAIM algorithm requires the observation noise obeying Gaussian distribution, but in some conditions it obeys non-Gaussian distribution. Particle filter is applicable to nonlinear and non-Gaussian system, thus RAIM algorithm performance is improved under non-Gaussian noise with particle filter method. However, particle degeneration interferes the performance of particle filter. In this paper, robust extended Kalman particle filter is proposed and applied to receiver autonomous integrity monitoring. The importance density function of particle filter is calculated by robust extended Kalman filter in order to improve the accuracy of state estimation when pseudo-range bias exists, and the particle degeneration is restrained. On this basis, the smoothed residual test statistics is set up for satellite fault detection and isolation. The simulation results show that RAIM algorithm based on robust extended Kalman particle filter and smoothed residual can well detect and isolate the faulty satellite under the condition of non-Gaussian observation noise. Compared to the RAIM algorithm based on particle filter, the new RAIM algorithm has a better performance on fault detection, and its position accuracy is improved.

A probabilistic spatiotemporal approach based on a spatial regression test (SRT-PS) is proposed for the quality control of climate data. It provides a quantitative probability that represents the uncertainty in each temperature observation. The assumption of SRT-PS is that there might be large uncertainty in the station record if there is a large residual difference between the record estimated in the spatial regression test and the true station record. The result of SRT-PS is expressed as a confidence probability ranging from 0 to 1, where a value closer to 1 indicates less uncertainty. The potential of SRT-PS to estimate quantitatively the uncertainty in temperature observations was demonstrated using an annual temperature dataset for China for the period 1971–2000 with seeded errors. SRT-PS was also applied to assess a real dataset, and was compared with two traditional quality control approaches: biweight mean and biweight standard deviation and SRT. The study provides a new approach to assess quantitatively the uncertainty in temperature observations at meteorological stations.

Hand, foot and mouth disease (HFMD) is a common infectious disease, causing thousands of deaths among children in China over the past two decades. Environmental risk factors such as meteorological factors, population factors and economic factors may affect the incidence of HFMD. In the current paper, we used a novel model—geographical detector technique to analyze the effect of these factors on the incidence of HFMD in China. We collected HFMD cases from 2,309 counties during May 2008 in China. The monthly cumulative incidence of HFMD was calculated for children aged 0–9 years. Potential risk factors included meteorological factors, economic factors, and population density factors. Four geographical detectors (risk detector, factor detector, ecological detector, and interaction detector) were used to analyze the effects of some potential risk factors on the incidence of HFMD in China. We found that tertiary industry and children exert more influence than first industry and middle school students on the incidence of HFMD. The interactive effect of any two risk factors increases the hazard for HFMD transmission.

In contrast to the plethora of publications on the separation of fatty acids, analogous studies involving fatty amines are scarce. A recently introduced ionic-liquid-based capillary column for GC was used to separate trifluoroacetylated fatty amines focusing on the analysis of a commercial sample. Using the ionic liquid column (isothermal mode at 200 °C) it was possible to separate linear primary fatty amines from C12 to C22 chain length in less 25 min with MS identification. The log of the amine retention factors are linearly related to the alkyl chain length with a methylene selectivity of 0.117 kcal/mol for the saturated amines and 0.128 kcal/mol for the mono-unsaturated amines. The sp2 selectivity for unsaturated fatty amines also could be calculated as 0.107 kcal/mol for the ionic liquid column. The commercial sample was quantified by GC with flame ionization detection (FID). An LC method also was developed with a reversed phase gradient separation using acetonitrile/formate buffer mobile phases and ESI-MS detection. Native amines could be detected and identified by their single ion monitoring chromatograms even when partial coelution was observed. The analysis of the commercial sample returned results coherent with those obtained by GC-FID and with the manufacturer's data.

Paired ion electrospray ionization (PIESI) mass spectrometry was developed as a useful technique that provides sensitive detection for anions in the positive ion mode. The ion-pairing reagent (IPR) utilized plays an essential role affecting the detection limits. This work describes the design and synthesis of two novel dications with unsymmetrical structures and their utilization for anion detection and mechanistic insights. The performance of dications was evaluated for seven selected anions in both single ion monitoring (SIM) mode and selected reaction monitoring (SRM) mode. The unsymmetrical dications allowed sensitive detection for these anions with down to subpicogram limits of detection (LOD) and an improved sensitivity from 1.5 to 12 times compared to the corresponding symmetrical dications. The enhanced sensitivity could be attributed to the surface activity of the unsymmetrical dications, which results in a concurrent strong partitioning of the anion to the aerosol droplet surface. Surface activity measurements of the anion/IPR complex were conducted, and a correlation between the observed ESI responses and the surface activity of the complex was found. The mechanism was further explored and explained based on the concepts of the equilibrium partitioning model (EPM).

While global warming during the last century has been well recognized, the magnitude of the climate warming in regions such as China over the past 100years still has some uncertainty due to limited observations during the early years. Several series of temperature anomalies for the 20(th) century in China have been independently developed by different groups. The uncertainty arises mainly from the sparse observations before 1950, where statistics are sensitive to the small and potentially biased sample. In this study, BSHADE-MSN (Biased Sentinel Hospitals Areal Disease Estimation and Means of Stratified Nonhomogeneous Surface), a combination of two novel distinct statistical methods that are applicable with different sample situations to a spatial heterogeneous surface, is applied to estimate annual mean temperature anomalies for China. This method takes into account prior knowledge of geographical spatial autocorrelation and nonhomogeneity of target domains, remedies the biased sample, and maximizes an objective function for the best linear unbiased estimation (BLUE) of the regional mean quantity. For the period 1900-1999, the overall trend estimated by BSHADE-MSN is 0.80 degrees C with a 95% confidential interval between 0.41 degrees C and 1.18 degrees C. This is significantly lower than that calculated by Climate Anomaly Method (CAM) and Block Kriging. The new temperature anomaly series for China exhibits slightly warmer conditions for the period before 1950 than existing studies. All the methods applied so far agree well with each other for the period after 1950, when there are sufficient stations across the country for the estimation of temperature anomaly series. Cross validation shows that the new regional mean temperature anomaly series has smaller estimation error variance and higher accuracy than those based on the other methods assessed in this study.

Photochemical catalytic CO2 reduction to formate and methanol has been demonstrated in an aqueous homogeneous system at pH 5.0 comprising ruthenium(II) trisphenanthroline as the chromophore, pyridine as the CO2 reduction catalyst, KCl, and ascorbic acid as a sacrificial reductant, using visible light irradiation at 470 ± 20 nm. Isotopic labeling with (13)CO2 yields the six-electron-reduced product (13)CH3OH. After 1 h photolysis, the two-electron-reduced product formate and the six-electron-reduced product methanol are produced with quantum yields of 0.025 and 1.1 × 10(–4), respectively. This represents 76 and 0.15 turnovers per Ru for formate and methanol, respectively, and 152 and 0.9 turnovers per Ru on an electron basis for formate and methanol, respectively. The system is inactive after 6 h irradiation, which appears largely to be due to chromophore degradation. A partial optimization of the methanol yield showed that high pyridine to Ru ratios are needed (100:1) and that the optimum pH is near 5.0. The presence of potassium salts enhances the yield in formate and methanol by 8- and 2-fold, respectively, compared to electrolyte-free solutions; however, other alkali and alkali earth cations have little effect. The addition of small amounts of solid metal catalysts immobilized on carbon had either no effect (M = Pt or Pd) or deleterious effects (M = Ni or Au) on methanol production. Addition of colloidal Pt resulted in no methanol production at all. This is in notable contrast with the pyridine-based electrocatalysis of CO2 to methanol in which metallic or conductive surfaces such as Pt, Pd, or p-type GaP are necessary for methanol formation.

Some climate datasets are incomplete at certain places and times. A novel technique called the point estimation model of Biased Sentinel Hospitals-based Area Disease Estimation (P-BSHADE) is introduced to interpolate missing data in temperature datasets. Effectiveness of the technique was empirically evaluated in terms of an annual temperature dataset from 1950 to 2000 in China. The P-BSHADE technique uses a weighted summation of observed stations to derive unbiased and minimum error variance estimates of missing data. Both the ratio and covariance between stations were used in calculation of these weights. In this way, interpolation of missing data in the temperature dataset was improved, and best linear unbiased estimates (BLUE) were obtained. Using the same dataset, performance of P-BSHADE was compared against three estimators: kriging, inverse distance weighting (IDW), and spatial regression test (SRT). Kriging and IDW assume a homogeneous stochastic field, which may not be the case. SRT employs spatiotemporal data and has the potential to consider temperature nonhomogeneity caused by topographic differences, but has no objective function for the BLUE. Instead, P-BSHADE takes into account geographic spatial autocorrelation and nonhomogeneity, and maximizes an objective function for the BLUE of the target station. In addition to the theoretical advantages of P-BSHADE over the three other methods, case studies for an annual Chinese temperature dataset demonstrate its empirical superiority, except for the SRT from 1950 to 1970.

In order to provide technical supports and visualization tools to the multi-GNSS related researches, 3D multi-GNSS visualization system (3DMVS) is designed and implemented. In this paper, the system requirements are analyzed at first and four modules (user interface module; display module; date calculating module; 3D models library module) are designed to realize the 3D visualization of the earth, satellites and orbits in different navigation system. Then the system general architecture is presented. Next, the system main process, data generation process and data visualization process is introduced. Dataflow between modules are illustrated in details by four steps. The visual C# programming tools and the 3D modeling software ZAM3D are used in the course of system implementation. The system has successfully applied in the related researches of multi-GNSS.

Global Navigation Satellite System (GNSS) signal simulator is one of the most important instruments for testing the function and performance of GNSS terminal products. It consists of a Mathematical Simulation System (MSS) and a Radio Frequency Signal Generator (RFSG). The MSS is responsible for generating the navigation message and observation data and then sending them to the RFSG in real time. The simulation accuracy of each part in the MSS determines that of the signal generated by the RFSG. In this paper, the function requirements of each module in MSS are analyzed firstly. Then the general framework of MSS is presented. At last, MSS developed in this paper is demonstrated and tested partly, the test results are compared with that of SimGEN software and STK. Taken as a whole, the MSS has complete functions and good performance. The MSS will hopefully apply to GNSS signal simulator.

Hand-foot-mouth disease (HFMD) is the most common and widespread infectious disease in the People's Republic of China. Although there has been a substantial increase of HFMD in many parts of the country in recent years, its spatial dynamics and determinants remain unclear. When we collected and analysed weekly data on HFMD cases from 1,456 counties and the corresponding meteorological factors from 1 May 2008 to 27 March 2009, it was found that HFMD was spatially dispersed across the country in the summer and winter, while clustered in the spring and autumn. The spatial variation of HFMD was found to be affected by a combination of climate variables, while its spatio-temporal transmission was largely driven by temperature variations with a 7-week lag implying that (i) the dispersal of the disease can be anticipated based on the variation of the temperature and other climate variables; and (ii) the spatial dynamics of HFMD can be robustly predicted 7 weeks ahead of time using temperature data only. The findings reported allow prompt preparation and implementation of appropriate public health interventions to control and prevent disease outbreaks.

To solve the problems which refer to share of design resources, and realize reasonable matching of design ability in the collaborative design process of complex product, a new Missile Design Service Platform based on Virtual Design Unit (MDSP-VDU) is proposed. Firstly, main function modules and characteristics of MDS-VDU are described. Secondly, key technologies including design resource virtualization, Virtual Design Unit construction, service description rules design services separation and combination,design process customization, VDUs scheduling are introduced. Thirdly, prototype system of MDS-VDU is built and displayed. Some theories about MDS-VDU have been applied in the implementation of missile design service platform and virtual resource management system in the Group-oriented enterprise CMfg Platform. Finally, application results show that MDSP-VDU is feasible.

A receiver autonomous integrity monitoring (RAIM) algorithm based on robust extended kalman filter (REKF) is used for detecting and identifying the micro pseudorange error in this paper. The micro pseudorange error propagation is controlled by REKF, and the test statistics is constructed precisely to detect and identify the error. The simulation results show that the RAIM algorithm based on REKF has a higher fault detection rate and fault identification rate for micro pseudorange error than the conventional RAIM algorithm based on conventional extended kalman filter (CEKF), besides, the position accuracy is improved.

The estimation of disease prevalence in online search engine data (e.g., Google Flu Trends (GFT)) has received a considerable amount of scholarly and public attention in recent years. While the utility of search engine data for disease surveillance has been demonstrated, the scientific community still seeks ways to identify and reduce biases that are embedded in search engine data. The primary goal of this study is to explore new ways of improving the accuracy of disease prevalence estimations by combining traditional disease data with search engine data. A novel method, Biased Sentinel Hospital-based Area Disease Estimation (B-SHADE), is introduced to reduce search engine data bias from a geographical perspective. To monitor search trends on Hand, Foot and Mouth Disease (HFMD) in Guangdong Province, China, we tested our approach by selecting 11 keywords from the Baidu index platform, a Chinese big data analyst similar to GFT. The correlation between the number of real cases and the composite index was 0.8. After decomposing the composite index at the city level, we found that only 10 cities presented a correlation of close to 0.8 or higher. These cities were found to be more stable with respect to search volume, and they were selected as sample cities in order to estimate the search volume of the entire province. After the estimation, the correlation improved from 0.8 to 0.864. After fitting the revised search volume with historical cases, the mean absolute error was 11.19% lower than it was when the original search volume and historical cases were combined. To our knowledge, this is the first study to reduce search engine data bias levels through the use of rigorous spatial sampling strategies., Author Summary Search engine data have been increasingly used to track the outbreak of diseases in recent years. Although these resources are free and are updated frequently, certain biases and weaknesses are embedded in search engine data, making their predictions inaccurate and even misleading. These inaccurate estimations may be caused by various factors, such as external interferences, the changing behaviors of online users, or biases inherent in the search engine data. Within a given region or province, different cities may suffer from these biases to varying degrees. Spatial sampling can serve as a useful method in addressing this problem. Using search data for Guangdong Province in China, this article illustrates the utility of rigorous spatial sampling techniques for reducing search engine data bias levels.

Background Severe acute respiratory syndrome (SARS) originated in China in 2002, and it spread to 26 provinces in mainland China and 32 countries across five continents in a matter of months. This outbreak resulted in 774 deaths. However, the spatial features and potential determinants of SARS input-output flows remain unclear. Methods We used an adjusted spatial interaction model to examine the spatial effects and potential factors associated with SARS input-output flows. Results The presence of origin-based spatial dependence positively affected SARS input-output flows from the neighbours of the origin regions. Two components of the input-output flows, migrant and hospitalization flows, exhibited distinctive features. The origin-based and destination-based spatial dependence positively affected migrant flows (i.e., due to those seeking jobs) from the neighbours of origin and destination locations. Similarly, the destination-based spatial dependence also positively affected hospitalization flows (i.e., due to those seeking treatment) from the neighbours of destination regions. However, the origin-to-destination based spatial dependence negatively affected hospitalisation flows from the neighbours of origin-to-destination regions. The direct effects accounted for 78 % of the SARS input-output flows, which was 3.56-fold greater than the indirect effects. Differences in regional income drove the SARS input-output flows. Therefore, urban income had a positive effect, whereas rural income had a negative effect. Total interregional flows increased by 3.54 % with a 1 % increase in urban income, and intraregional flows increased by 8.35 %. In contrast, the total interregional flows decreased by 3.38 % with a 1 % increase in rural income, and intraregional flows declined by 2.29 %. Railway capacity, per person gross domestic product (PGDP), urban rate and the law of distance decay also affected the input-output flows. Conclusions Our results confirm that the SARS input-output flows presented significant geographic spatial heterogeneity and spatial effects. Income differences were the major cause of the flows between pairs of regions. Railway capacity, PGDP, and urban rate also played important roles. These findings provide valuable information for the Chinese government to control the future spread of nationwide epidemics. Electronic supplementary material The online version of this article (doi:10.1186/s12889-016-2867-6) contains supplementary material, which is available to authorized users.

Identifying factors that influence the land surface temperature (LST) of urban forests can help improve simulations and predictions of spatial patterns of urban cool islands. This requires a quantitative analytical method that combines spatial statistical analysis with multi-source observational data. The purpose of this study was to reveal how human activities and ecological factors jointly influence LST in clustering regions (hot or cool spots) of urban forests. Using Xiamen City, China from 1996 to 2006 as a case study, we explored the interactions between human activities and ecological factors, as well as their influences on urban forest LST. Population density was selected as a proxy for human activity. We integrated multi-source data (forest inventory, digital elevation models (DEM), population, and remote sensing imagery) to develop a database on a unified urban scale. The driving mechanism of urban forest LST was revealed through a combination of multi-source spatial data and spatial statistical analysis of clustering regions. The results showed that the main factors contributing to urban forest LST were dominant tree species and elevation. The interactions between human activity and specific ecological factors linearly or nonlinearly increased LST in urban forests. Strong interactions between elevation and dominant species were generally observed and were prevalent in either hot or cold spots areas in different years. In conclusion, quantitative studies based on spatial statistics and GeogDetector models should be conducted in urban areas to reveal interactions between human activities, ecological factors, and LST.

Description of O-D variables of SARS input-output flows. Table S2. SARS input-output flows matrix. Table S3. SARS input-output flows estimated using gravity model. Table S4. Direct and indirect effects of SARS input-output flows estimated using an ASIM. (DOC 204Â kb)

As one solution to complex product design, the integrated design environment has experienced several decades of development with great changes. This paper reviews the emergence, development history and future trend of integrated design environment. Firstly, the concept and connotation of design are analyzed, and then from the development of design behavior and the development of computer aided design, the inevitability and development history of integrated design environment are elaborated. Secondly, the background and characteristic of different kinds of integrated design environment were analyzed and elaborated. Finally, based on the trend analysis of the integrated design environment, future research direction and goals are proposed. Through this review, basic materials and direction for the related academic research can be provided.

Rationale The detection of metal cations continues to be essential in many scientific and industrial areas of interest. The most common electrospray ionization mass spectrometry (ESI-MS) approach involves chelating the metal ions and detecting the organometallic complex in the negative ion mode. However, it is well known that negative ion mode ESI-MS is generally less sensitive than the positive ion mode. To achieve greater sensitivity, it is necessary to examine the feasibility of detecting the chelated metal cations in positive ion mode ESI-MS. Methods Since highly solvated native metal cations have relatively low ionization efficiency in ESI-MS, and can be difficult to detect in the positive ion mode, a tetracationic ion-pairing agent was added to form a complex with the negatively charged metal chelate. The use of the ion-pairing agent leads to the generation of an overall positively charged complex, which can be detected at higher m/z values in the positive ion mode by electrospray ionization linear quadrupole ion trap mass spectrometry. Results Thirteen chelating agents with diverse structures were evaluated in this study. The nature of the chelating agent played as important a role as was previously determined for cationic pairing agents. The detection limits of six metal cations reached sub-picogram levels and significant improvements were observed when compared to negative ion mode detection where the metal-chelates were monitored without adding the ion-pairing reagent (IPR). Also, selective reaction monitoring (SRM) analyses were performed on the ternary complexes, which improved detection limits by one to three orders of magnitude. Conclusions With this method it was possible to analyze the metal cations in the positive ion mode ESI-MS with the advantage of speed, sensitivity and selectivity. The optimum solution pH for this type of analysis is 5-7. Tandem mass spectrometry (MS/MS) further increases the sensitivity. Speciation is straightforward making this a broadly useful approach for the analysis of metal ions.

The helicopter Maintenance, Repair and Overhaul/Operations (MRO) system enables the best sharing of the maintenance resources and maintenance ability in a wide area, so as to promote the specialization of the helicopter maintenance organizations. Information acquisition is an important and difficult part of the helicopter MRO system. This paper systematically analyzes the condition monitoring methods which are used to monitor the rotational speed, temperature, pressure, vibration and flight parameter in different parts of a helicopter, and then it puts forward some improved ways for information acquisition. Considering the helicopter’s features, the process of information acquisition is illustrated. In addition, this paper presents the basic requirements of data sampling, and it also shows a detailed discussion on data format and data transmission in the helicopter MRO system. At the end of the paper, a system mode and architecture of helicopter MRO system are proposed.

Metals play a very important role in many scientific and environmental fields, and thus their detection and analysis is of great necessity. A simple and very sensitive method has been developed herein for the detection of metals in positive ion mode ESI-MS. Metal ions are positively charged, and as such they can potentially be detected in positive ion mode ESI-MS; however, their small mass-to-charge (m/z) ratio makes them fall in the low-mass region of the mass spectrum, which has the largest background noise. Therefore, their detection can become extremely difficult. A better and well-known way to detect metals by ESI-MS is by chelating them with complexation agents. In this study eleven different metals, Fe(II), Fe(III), Mg(II), Cu(II), Ru(III), Co(II), Ca(II), Ni(II), Mn(II), Sn(II), and Ag(I), were paired with two commercially available chelating agents: ethylenediaminetetraacetic acid (EDTA) and ethylenediaminedisuccinic acid (EDDS). Since negative ion mode ESI-MS has many disadvantages compared to positive ion mode ESI-MS, it would be very beneficial if these negatively charged complex ions could be detected in the positive mode. Such a method is described in this paper and it is shown to achieve much lower sensitivities. Each of the negatively charged metal complexes is paired with six cationic ion-pairing reagents. The new positively charged ternary complexes are then analyzed by ESI-MS in the positive single ion monitoring (SIM) and single reaction monitoring (SRM) modes. The results clearly revealed that the presence of the cationic reagents significantly improved the sensitivity for these analytes, often by several orders of magnitude. This novel method developed herein for the detection of metals improved the limits of detection (LODs) significantly when compared to negative ion mode ESI-MS and shows great potential in future trace studies of these and many other species.

Based on the concept of Cloud Computing, Cloud Manufacturing which refers to a new networked manufacturing mode is proposed by LI Bo-hu. In this new mode, virtual resources are organized to meet the requirements of various manufacturing services for users over network and Cloud Manufacturing platform. This paper focuses on the virtualization of resources and analyses the factors which affect the classification of virtual resources in Cloud Manufacturing first, and a conceptual classification is given. Then some factors affect the result of task assignment are introduced, and a simple example shows the effect of these factors to task assignment. Based on these factors which include quantitative, human activity, logistics and granularity, a modeling process and a rough model of virtual resource are built.

The spatiotemporal distribution pattern of the surface temperatures of urban forest canopies (STUFC) is influenced by many environmental factors, and the identification of interactions between these factors can improve simulations and predictions of spatial patterns of urban cool islands. This quantitative research uses an integrated method that combines remote sensing, ground surveys, and spatial statistical models to elucidate the mechanisms that influence the STUFC and considers the interaction of multiple environmental factors. This case study uses Jinjiang, China as a representative of a city experiencing rapid urbanization. We build up a multisource database (forest inventory, digital elevation models, population, and remote sensing imagery) on a uniform coordinate system to support research into the interactions that influence the STUFC. Landsat-5/8 Thermal Mapper images and meteorological data were used to retrieve the temporal and spatial distributions of land surface temperature. Ground observations, which included the forest management planning inventory and population density data, provided the factors that determine the STUFC spatial distribution on an urban scale. The use of a spatial statistical model (GeogDetector model) reveals the interaction mechanisms of STUFC. Although different environmental factors exert different influences on STUFC, in two periods with different hot spots and cold spots, the patch area and dominant tree species proved to be the main factors contributing to STUFC. The interaction between multiple environmental factors increased the STUFC, both linearly and nonlinearly. Strong interactions tended to occur between elevation and dominant species and were prevalent in either hot or cold spots in different years. In conclusion, the combining of multidisciplinary methods (e.g., remote sensing images, ground observations, and spatial statistical models) helps reveal the mechanism of STUFC on an urban scale.

For complex product design, many software and tools are used, and large scale intermediate data with heterogeneous formats and complex relationships are produced in preliminary design. Efficient organization and management of data are very difficult. The integrated design environments(IDE) are useful to solve this problem. This paper gives an overview on IDE and some correlative key technologies. According to characteristics of preliminary design stage, a framework of IDE is put forward in this paper and the system function components are analyzed. The framework includes some innovative methodologies, such as task-drove design by workflow management, design tools and software seamless integration, and design knowledge templates. The realization of IDE is presented to illustrate the applicability of the new framework.

The availability of advanced receiver autonomous integrity monitoring for vertical guidance down to altitudes of 200 ft (LPV-200) is discussed using real satellite orbit/ephemeris data collected at eight international global navigation satellite system service stations across China. Analyses were conducted for the availability of multi-constellation advanced receiver autonomous integrity monitoring and multi-fault advanced receiver autonomous integrity monitoring, and the sensitivity of availability in response to changes in error model parameters (i.e. user range accuracy, user range error, Bias-Nom and Bias-Max) was used to compute the vertical protection level. The results demonstrated that advanced receiver autonomous integrity monitoring availability based on multiple constellations met the requirements of LPV-200 despite multiple-fault detections that reduced the availability of the advanced receiver autonomous integrity monitoring algorithm; the advanced receiver autonomous integrity monitoring availability thresholds of the user range error and Bias-Nom used for accuracy were more relevant to geographic information than the user range accuracy and Bias-Max used for integrity at the eight international global navigation satellite system service stations. Finally, the possibility of using the advanced receiver autonomous integrity monitoring algorithm for a Category III navigation standard is discussed using two sets of predicted errors, revealing that the algorithm could be used in 79% of China.

As urban thermal environments are being caused by global climatic changes and urbanization is not uniform on diurnal, seasonal, or annual scales, the spatiotemporal patterns of surface urban heat islands (SUHI) similarly vary between cities across regions. This research assessed the spatiotemporal variations in SUHI intensities (SUHII), and then revealed their spatiotemporal patterns and relationships that existed within 32 major cities in China using spatialization technologies, such as the self-organizing map (SOM) method and statistical methods. Results showed that the spatial patterns of the SUHII patterns in China were significantly affected by the climatic types, whereas human heat discharge also disturbed the patterns to a certain extent. Specifically, the daytime SUHIIs in China had much higher seasonal variations in North China than in South China. The nighttime SUHIIs were much weaker and more stable than the daytime SUHIIs, and had far more obvious spatial patterns with much higher values in North China than in South China. As for the temporal regimes, the temporal variation in the SUHIIs in one city was more related to the development of the urbanization. To be specific, not all cities were experiencing increasingly worse urban thermal environments with urbanization as reported by previous studies. This research not only proposes a spatiotemporal framework to study the SUHIIs patterns and their relationships, but also provides an in-depth and comprehensive understanding of SUHIIs in China.

Built-in electric field may enhance or retard the impurity-free vacancy disordering (IFVD) during rapid thermal annealing (RTP) by imposing a drift on charged point defects. Built-in electric field is at the interface between dielectric layer and top layer of the structure. Subsequent rapid thermal annealing leads to different intermixing results due to different field directions on InP cap layers in different doping types. Experimental results also show different influences of the built-in field on the two sublattices largely due to different charge numbers of point defects.

An effective and reliable synthetic route has been developed for the preparation of almost perfectly monodisperse 3 to ∼4 nm ZnO nanocrystals. In addition, a PL peak with a blue-shift of 0.16 eV has been observed in the PL spectrum, showing good size uniformity of the nanodots. The band gap has also been verified in the analysis of I−V characteristics of an ITO/ZnO/SiO2/Al structure, from which the band alignment of the ZnO nanodots on ITO has been determined. This work demonstrates an efficient synthesis of ZnO nanodots and an easy approach to studying physical properties of nanocrystals that will help the material optimization in device application.

The principle of extended Kalman filter (EKF), unscented Kalman filter (UKF) algorithm, and unscented transformation (UT) is studied. To simply the process of obtaining sigma points in UKF, an improved UKF algorithm is mentioned in this chapter. The theory formulation and computer simulation have been done for the comparison of these three nonlinear Kalman filters. Results show that all of them can accomplish the estimation task, but the improved UKF has higher accuracy and less computation cost than the other two.

Vertical cavity surface emitting laser (VCSEL) emitting at 850 nm plays more important role in local fiber communication. Most of the VCSEL products emitting at 850 nm are fabricated by ion implanting. Their threshold current is about 4– 6 mA . Using tungsten wires as mask, we developed the parameter of implantation and fabricated 850 nm VCSEL under room temperature CW (continuous wave) operation. The threshold current was 1.4 mA , which was lower than that of most similar devices reported before. The resistance of the device was 206 Ω . The light power was 0.92 mW at 6.74 mA under room temperature CW operation, while the light power did not achieve obvious saturation. The most remarkable advantage was that the fabrication method was simple and the optimization was available to implanting parameter.

In order to increase the optical output power of semiconductor superluminescent device, a direct coupling method had been used to integrate, monolithically, the superluminescent diode with a semiconductor optical amplifier. By this means, two kinds of integrated superluminescent light source have been fabricated. High output power was obtained in pulsed operation.

Background Bacillary dysentery remains a major public health concern in China. The Beijing–Tianjin–Tangshan urban region is one of the most heavily infected areas in the country. This study aimed to analyze epidemiological features of bacillary dysentery, detect spatial-temporal clusters of the disease, and analyze risk factors that may affect bacillary dysentery incidence in the region. Methods Bacillary dysentery case data from January 2011 to December 2011 in Beijing–Tianjin–Tangshan were used in this study. The epidemiological features of cases were characterized, then scan statistics were performed to detect spatial temporal clusters of bacillary dysentery. A spatial panel model was used to identify potential risk factors. Results There were a total of 28,765 cases of bacillary dysentery in 2011. The results of the analysis indicated that compared with other age groups, the highest incidence (473.75/105) occurred in individuals

International audience; In contrast to the plethora of publications on the separation of fatty acids, analogous studies involving fatty amines are scarce. A recently introduced ionic-liquid-based capillary column for GC was used to separate trifluoroacetylated fatty amines focusing on the analysis of a commercial sample. Using the ionic liquid column (isothermal mode at 200°C) it was possible to separate linear primary fatty amines from C12 to C22 chain length in less 25 min with MS identification. The log of the amine retention factors are linearly related to the alkyl chain length with a methylene selectivity of 0.117 kcal/mol for the saturated amines and 0.128 kcal/mol for the mono-unsaturated amines. The sp(2) selectivity for unsaturated fatty amines also could be calculated as 0.107 kcal/mol for the ionic liquid column. The commercial sample was quantified by GC with flame ionization detection (FID). An LC method also was developed with a reversed phase gradient separation using acetonitrile/formate buffer mobile phases and ESI-MS detection. Native amines could be detected and identified by their single ion monitoring chromatograms even when partial coelution was observed. The analysis of the commercial sample returned results coherent with those obtained by GC-FID and with the manufacturer's data.

GNSS (Global Navigation Satellite System) simulation system is a powerful tool for designing GNSS and researching the related problem of that efficiently. The trajectory and motion information generation of vehicles is an important part of scenario design in GNSS simulation system. In this part, the trajectory generation based on waypoint data is the most complicated. It involves the trajectory planning, vehicle kinematics, solution of geodetic problem and other related research fields. The trajectory generation based on waypoint set by the user is an inverse solution of geodetic problem actually. According to the study and comparison of different solutions of geodetic problem, and taking into account the requirement of the vehicle trajectory accuracy and computation complexity in GNSS simulation system, an inverse solution of geodetic problem based on the local earth reference ellipsoid and partial spherical assumption is put forward in this paper. Compared with the existing algorithms, a certain availability of the inverse solution in this paper within the limits is verified. Given the kinematics characteristics of vehicles, ships and aircrafts, the corresponding method of waypoint trajectory generation is designed. At last, the solution mentioned above is implemented by C#, and it has also been applied to a GNSS simulation platform successfully.

As a new kind of networked manufacturing mode, Cloud Manufacturing needs to construct a large-scale virtual manufacturing resources pool firstly. For a reasonable and effective construction of the virtual manufacturing resources pool, the point of multi-granularity virtualization is proposed. Firstly, by analyzing the process of resources virtualization, the meanings of manufacturing resources, virtualization modeling and virtualization accessing are stated, and the relationships between them are illustrated; secondly, by analyzing the compositionality of resources, two resources categories are deduced; thirdly, the granularity factor, which have serious impacts on the resources-virtualization, resources-matching and resources-scheduling, are discussed; finally, a multi-granularity virtualization method of manufacturing resources is proposed.Copyright © 2013 by ASME

A novel method based on the paired ion electrospray ionization (PIESI) mass spectrometry has been developed for determination of acidic pesticides at ultratrace levels in surface and ground waters. The proposed approach provides greatly enhanced sensitivity for acidic pesticides and overcomes the drawbacks of the less sensitive negative ion mode ESI-MS. The limits of detection (LODs) of 19 acidic pesticides were evaluated with four types of dicationic ion-pairing reagent (IPR) in both single ion monitoring (SIM) and selected reaction monitoring (SRM) mode. The LOD of 19 pesticides obtained with the use the optimal dicationic ion-pairing reagent ranged from 0.6pg to 19pg, indicating the superior sensitivity provided by this method. The transition pathways for different pesticide-IPR complexes during the collision induced dissociation (CID) were identified. To evaluate and eliminate any matrix effects and further decrease the detection limits, off-line solid-phase extraction (SPE) was performed for DI water and a river water matrix spiked with 2000ng L(-1) and 20ng L(-1) pesticides standards respectively, which showed an average percent recovery of 93%. The chromatographic separation of the acidic pesticides was conducted by high-performance liquid chromatography (HPLC) using a C18 column (250mm×2.1mm) in the reversed phase mode using linear gradient elution. The optimized HPLC-PIESI-MS/MS method was utilized for determination of acidic pesticide at ng L(-1) level in stream/pond water samples. This experimental approach is 1-3 orders of magnitude more sensitive for these analytes than other reported methods performed in the negative ion mode.