Export price of rare earths in Shanghai Customs increased in the first quarter of 2019

According to statistics from Shanghai Customs, in the first quarter of 2019, Shanghai Customs totally exported 3,022.3 tons of rare earths, down 0.5% from the same period last year;export value reached RMB 340 million, up 3.4%;the average export price was 110,000 yuan per ton, up 3.9%.

Establishment of Fluorescence Quantitative RT-PCR Assay for Detection of Equine Arteritis Virus

[Objective]The paper was to establish a fluorescence quantitative RT-PCR method for detection of equine arteritis virus(EAV).[Method]Primers and probes were developed for the EAV ORF7 gene sequence,and the reaction system was optimized.Standard curves were established,leading to the initial development of the EAV fluorescence quantitative RT-PCR assay.The accuracy,specificity,and sensitivity of this method were subsequently evaluated.[Result]The EAV fluorescence quantitative RT-PCR assay demonstrated optimal performance at an annealing temperature of 61 C,with a final concentration of primer and probe set at 0.6μmol/L.The plasmid standard demonstrated a strong linear correlation with Ct values within the range of 1.6×10^(7)-1.6×10^(2)copies/μL.The equation of the standard curve was determined to be y=-2.68x+32.88,with an R^(2) value of 0.9927.Consequently,the EAV fluorescence quantitative RT-PCR assay was successfully established.The methodology employed was effective in detecting EAV,Theileria equi,equine herpesvirus-1(EHV-1),equine herpesvirus-4(EHV-4),and equine influenza virus(EIV).The findings indicated that the method was specifically capable of detecting EAV,while the other pathogens tested yielded negative results.The method demonstrated a high degree of specificity.It was employed to detect the standard plasmid cRNA synthesized through in vitro transcription following a 10-fold dilution.The results indicated that the minimum detection limit of the method was 1.6×10^(2) copies/μL,and it exhibited high sensitivity.The coefficient of variation,both within and between groups,was maintained at 1.8%,indicating good reproducibility.In this study,the fluorescence quantitative RT-PCR assay developed was utilized alongside the EAV fluorescence quantitative RT-PCR assay established by previous researchers to analyze a total of 234 clinical samples.Both methods yielded a positive detection rate of 14.1%,and the coincidence rate between the two techniques was found to be 100%.[Conclusion]The fluorescence quantitative RT-PCR assay developed in this study offers a novel approach and concept for the prevention and control of equine viral arteritis(EVA).

Analysis of the Dynamics of Policy Changes in the International Border Cooperation Center under the Perspective of Multi-Source Flow Theory

The China-Kazakhstan Horgos Frontier International Cooperation Center has been established for nearly 20 years,and its targeted policies have gone through the stages of initiative,negotiation and modification,official operation,and optimization and enhancement.This paper explores the problems,policy,and political sources of policy changes since the establishment of the Horgos International Border Cooperation Center by applying the multi-source flow theory to find the opening of the problematic and political windows.It also constructs a model of policy change dynamics to provide suggestions on how the government should better promote the good development of China’s first transnational cooperation center.

Research on Tax Risk Regulation and Strategic Management in the Context of Big Data

With the rapid development of big data,big data has been more and more applied in all walks of life.Under the big data environment,massive big data provides convenience for regional tax risk control and strategic decision-making but also increases the difficulty of data supervision and management.By analyzing the status quo of big data and tax risk management,this paper finds many problems and puts forward effective countermeasures for tax risk supervision and strategic management by using big data.

Exploring Corporate Tax Compliance in the Era of Digital Tax Collection and Administration:Insights from the“Golden Tax Phase Four”Project

This article primarily examines the current state of tax collection and management,alongside other associated issues.It integrates insights from China’s“14th Five-Year Plan”and anticipates the imminent implementation of the“Golden Tax Phase Four.”With this backdrop,the article offers recommendations for advancing the reform of the tax collection and management system,fostering the development of intelligent taxation,and accelerating the modernization of tax collection and management in China.

Water resource forecasting with machine learning and deep learning:A scientometric analysis

Water prediction plays a crucial role in modern-day water resource management,encompassing both logical hydro-patterns and demand forecasts.To gain insights into its current focus,status,and emerging themes,this study analyzed 876 articles published between 2015 and 2022,retrieved from the Web of Science database.Leveraging CiteSpace visualization software,bibliometric techniques,and literature review methodologies,the investigation identified essential literature related to water prediction using machine learning and deep learning approaches.Through a comprehensive analysis,the study identified significant countries,institutions,authors,journals,and keywords in this field.By exploring this data,the research mapped out prevailing trends and cutting-edge areas,providing valuable insights for researchers and practitioners involved in water prediction through machine learning and deep learning.The study aims to guide future inquiries by highlighting key research domains and emerging areas of interest.

Joint optimization of maintenance inspection and spare provisioning for aircraft deteriorating parts

With the wide application of condition based maintenance(CBM) in aircraft maintenance practice, the joint optimization of maintenance and inventory management, which can take full advantage of CBM and reduce the aircraft operational cost, is receiving increasing attention. In order to optimize the inspection interval, maintenance decision and spare provisioning together for aircraft deteriorating parts, firstly, a joint inventory management strategy is presented, then, a joint optimization of maintenance inspection and spare provisioning for aircraft parts subject to the Wiener degradation process is proposed based on the strategy.Secondly, a combination of the genetic algorithm(GA) and the Monte Carol method is developed to minimize the total cost rate.Finally, a case study is conducted and the proposed joint optimization model is compared with the existing optimization model and the airline real case. The results demonstrate that the proposed model is more beneficial and effective. In addition, the sensitivity analysis of the proposed model shows that the lead time has higher influence on the optimal results than the urgent order cost and the corrective maintenance cost, which is consistent with the actual situation of aircraft maintenance practices and inventory management.

Study on the structure characterization and moisturizing effect of Tremella polysaccharide fermented from GCMCC5.39

The structure and moisture retention of Tremella polysaccharide fermented from GCMCC5.39(FTP)were evaluated.After UV,infrared spectrum analysis,HPAEC-PAD,HPSEC and 1 D NMR analysis,the composition of the purifi ed FTP was determined.Purifi ed components of fermented Tremella polysaccharide(FTPS)was made of galactose,mannose,glucose,galactosmine,glucosamine,and contain a large amount of hydroxyl,carbonyl and amino groups.FTPS wasα-neutral pyranose without uronic acid.FTPS-1 and FTPS-2 were obtained after purifi cation by DEAE-Sepharose Fast Flow Column.The molecular weights of FTPS-1 and FTPS-2 were 25722 and 177263 Da.FTPS-2 had a better ability to prevent moisture loss,and the optimal moisture retention period was 0–4 h.FTPS-2 could signifi cantly increase the moisture content of the skin epidermis and showed a dose-concentration relationship.The effect of FTPS-2 on the expression of different moisturizing genes was evaluated in a human skin keratinocyte model.The results showed that FTPS-2 has no cytotoxicity,and could signifi cantly promote AQP3,TGM1,CASP14,HYAL2,FLG gene expression level in HaCaT cells.It has the most signifi cant infl uence at HYAL2 protein expression on 50μg/mL.

Delay-dependent stability of linear multistep methods for differential systems with distributed delays

This paper deals with the stability of linear multistep methods for multidimensional differential systems with distributed delays. The delay-dependent stability of linear multistep methods with compound quadrature rules is studied. Several new sufficient criteria of delay-dependent stability are obtained by means of the argument principle. An algorithm is provided to check delay-dependent stability. An example that illustrates the effectiveness of the derived theoretical results is given.

Research and Implementation of the Enterprise Evaluation Based on a Fusion Clustering Model of AHP-FCM

Traditional clustering method is easy to slow convergence speed because of high data dimension and setting random initial clustering center. To improve these problems, a novel method combining subtractive clustering with fuzzy C-means( FCM)clustering will be advanced. In the method, the initial cluster number and cluster center can be obtained using subtractive clustering. On this basis,clustering result will be further optimized with FCM. In addition,the data dimension will be reduced through the analytic hierarchy process( AHP) before clustering calculating.In order to verify the effectiveness of fusion algorithm,an example about enterprise credit evaluation will be carried out. The results show that the fusion clustering algorithm is suitable for classifying high-dimension data,and the algorithm also does well in running up processing speed and improving visibility of result. So the method is suitable to promote the use.

Static output feedback stabilization for second-order singular systems using model reduction methods

In this paper,the static output feedback stabilization for large-scale unstable second-order singular systems is investigated.First,the upper bound of all unstable eigenvalues of second-order singular systems is derived.Then,by using the argument principle,a computable stability criterion is proposed to check the stability of secondorder singular systems.Furthermore,by applying model reduction methods to original systems,a static output feedback design algorithm for stabilizing second-order singular systems is presented.A simulation example is provided to illustrate the effectiveness of the design algorithm.

Quantitative analysis and time-resolved characterization of simulated tokamak exhaust gas by laser-induced breakdown spectroscopy

Tokamak exhaust is an important part of the deuterium-tritium fuel cycle system in fusion reactions.In this work,we present a laser-induced breakdown spectroscopy(LIBS)-based method to monitor the gas compositions from the exhaust system in the tokamak device.Helium(He),a main impurity in the exhaust gas,was mixed with hydrogen(H_(2))in different ratios through a self-designed gas distribution system,and sealed into a measurement chamber as a standard specimen.A 532 nm wavelength laser pulse with an output power of 100 mJ was used for plasma excitation.The time-resolved LIBS is used to study the time evolution characteristics of the signal strength,signal-to-background ratio(SBR),signal-to-noise ratio(SNR)and relative standard deviation(RSD)of the helium and hydrogen characteristic lines.The Boltzmann twoline method was employed to estimate the plasma temperature of laser-induced plasma(LIP).The Stark-broadened profile of He I 587.56 nm was exploited to measure the electron density.From these studies,an appropriate time was determined in which the low RSD%was consistent with the high signal-to-noise ratio.The He I 587.56 nm and Hαemission lines with good signalto-noise ratio were extracted from the spectrum and used in the external standard method and internal standard method for quantitative analysis.The test results for mixed gas showed that the average relative error of prediction was less than 11.15%,demonstrating the great potential of LIBS in detecting impurities in plasma exhaust gas.

Joint optimization of sampling interval and control for condition-based maintenance using availability maximization criterion

Most of the maintenance optimization models in condition-based maintenance(CBM) consider the cost-optimal criterion, but few papers have dealt with availability maximization for maintenance applications. A novel optimal Bayesian control approach is presented for maintenance decision making. The system deterioration evolves as a three-state continuous time hidden semi-Markov process. Considering the optimal maintenance policy, the multivariate Bayesian control scheme based on the hidden semi-Markov model(HSMM) is developed, the objective is to maximize the long-run expected average availability per unit time. The proposed approach can optimize the sampling interval and control limit jointly. A case study using Markov chain Monte Carlo(MCMC)simulation is provided and a comparison with the Bayesian control scheme based on hidden Markov model(HMM), the age-based replacement policy, Hotelling’s T2, multivariate exponentially weihted moving average(MEWMA) and multivariate cumulative sum(MCUSUM) control charts is given, which illustrates the effectiveness of the proposed method.

InvasionDB: A genome and gene database of invasive alien species

Invasive alien species(IAS) are species whose introduction to areas outside of their native range cause harm to economics, biodiversity, and the environment. Understanding the genetic basis of invasiveness is critical for preventing invasion by an alien species and managing IAS with eco-friendly control methods. In addition, uncovering the genomic features of IAS is essential for accurately predicting invasiveness. However, even though increasing efforts have been devoted to sequencing the genomes of IAS, there is still not an integrated genome database for the invasive biology community. Here, we first determined a list of invasive plants and animals by mining references and databases. Then, we retrieved the genomic and gene data of these IAS, and constructed a database, Invasion DB. Invasion DB encompasses 131 IAS genomes, 76 annotated IAS assemblies, and links these data to conventional functions such as searching for gene coding sequences and Pfam, KEGG, NR annotations, BLAST server, JBrowse, and downloads services. Next, we analyzed 19 invasivenessrelated gene families which confer invasiveness in insects. To study the roles of noncoding RNA in invasiveness, we also annotated 135 494 mi RNAs, 89 294 r RNAs, and 2 671 941 t RNAs from these IAS. In summary, Invasion DB is useful for studying the invasiveness at the genomic level, and thus helps to develop novel management strategies to control IAS.

Features of Egypt’s Water Transportation and China’s Participation in Egypt’s Port Construction

There are four distinctive features in Egypt’s port construction and maritime transportation:Egypt’s port construction and maritime transportation is a vital part of the international shipping system;maritime transportation is an important backbone industry in Egypt;Egypt’s port construction propels its domestic economy and international interaction;and the capacity for ocean shipping still needs upgrading.China’s participation in Egypt’s port construction is,on one side,the further demand of China’s economic globalization,and on the other side,it is an outcome of the beneficial interactions between China and Egypt.Egypt’s port construction has started a new chapter ever since Abdel Fattah al Sisi assumed power.As opportunities and risks coexist in China’s participation in Egypt’s port construction,only when we are fully aware of the risks and make scientific decisions based on China’s own strengths can we effectively participate in Egypt’s port construction to yield a win-win result.

Inter-laboratory Validation of Real-time PCR Assays for Goat-,Horse-and Donkey-derived Material in Meat Products

In this study,we performed an inter-laboratory collaborative ring trial to develop and validate specific TaqMan real-time PCR assays for goat-,horse-,and donkey-derived material in meat products.The performances of these assays in different environments and situations were comprehensively evaluated.This ring trial involved the participation of 12 laboratories in Europe and Asia.The results from the participating laboratories were analyzed to determine the specificity,accuracy,false positive rate,limit of detection(LOD),and probability of detection(POD)of the developed assays.Statistical analysis showed that the false positive and negative rates were zero,the LOD was five copies/reaction,and the laboratory standard deviation(σ_(L))was 0.30 for all three assays.Thus,the results demonstrate that the developed methods are robust and suitable for the detection and identification of goat-,horse-,and donkey-derived materials in meat products.

A Spectral Method for Convection-Diffusion Equations

In the practical problems such as nuclear waste pollution and seawater intrusion etc., many problems are reduced to solving the convection-diffusion equation, so the research of convection-diffusion equation is of great value. In this work, a spectral method is presented for solving one and two dimensional convection-diffusion equation with source term. The finite difference method is also used to solve the convection diffusion equation. The numerical experiments show that the spectral method is more efficient than other methods for solving the convection-diffusion equation.

Research of Maintenance Task Interval Optimization of Elevator Hydraulic Actuation System

In order to solve the best maintenance interval problem of the elevator hydraulic actuation systems on civil aircraft, a method based on reliability and cost minimum is introduced in this paper. The estimation of system reliability is presented by using two-parameter Weibull distributions. The parameters are estimated by using Weibull probability statistical analysis and the practical operational data. Then, the maintenance optimization model isformulated where the objective function is to minimize the expected schedule maintenance cost in a time unit. The results of numerical example show that the proposed model could scheme the optimal maintenance intervals for the considered system when the parameters are given. This research has certain significance in theoryand engineering practice.

Assessment of the Potential for Cross-Border Transmission of Infectious Diseases via Commercial Air Travel—Shanghai Municipality,China,2019-2023

What is already known about this topic?Despite the end of coronavirus disease 2019(COVID-19)as a public health emergency of international concern(PHEIC),the changes in risks of travel-related infectious diseases and their impact on global health quarantine still call for great concern.What is added by this report?Our study indicated that the pattern of changes in the positive detection rate of arrivals was basically in line with the disease incidence in countries from which travel was initiated.What are the implications for public health practice?Accurate risk assessment at entry-exit ports can significantly enhance the efficiency of targeting highrisk international arrivals,especially in the early stages of epidemic control and prevention when available data are insufficient.

A Sensitive Fluorescent Turn-on Probe NapP-deap Based on Naphthalimide Derivative to Detect Hg(II) Ions in HEPES Buffer Solution and Living Cells

A highly sensitive fluorescent“turn-on”probe NapP-deap based on naphthalimide derivative was developed that bound Hg^2+ ions rapidly in the N-2-hydroxyethylpiperazine-N-ethane-sulphonic acid(HEPES)buffer solution via photo-induced electron transfer(PET)being inhibited mechanism.The titration experiment displayed that the emission intensity of NapP-deap at 540 nm was almost linearly increased by about 3-fold.The Job’s plot showed a stoichiometry factor of 1:1 of the ligand-to-metal ratio.The detection limit of fluorescent probe was calculated to be 6.2×10^?9 mol/L.^1H NMR studies could confirm that one Hg^2+ ion was bound by the N atoms(a,b)of piperazine or the N atom(c)of pyridine.The fluorescent probe could be used for the detection of Hg^2+ ions in living cells.