Winter jujube(Ziziphus jujuba'Dongzao')is greatly appreciated by consumers for its excellent quality,but brand infringement frequently occurs in the market.Here,we first determined a total of 38 elements in 16...Winter jujube(Ziziphus jujuba'Dongzao')is greatly appreciated by consumers for its excellent quality,but brand infringement frequently occurs in the market.Here,we first determined a total of 38 elements in 167 winter jujube samples from the main winter jujube producing areas of China by inductively coupled plasma mass spectrometer(ICP-MS).As a result,16 elements(Mg,K,Mn,Cu,Zn,Mo,Ba,Be,As,Se,Cd,Sb,Ce,Er,Tl,and Pb)exhibited significant differences in samples from different producing areas.Supervised linear discriminant analysis(LDA)and orthogonal projection to latent structures discriminant analysis(OPLS-DA)showed better performance in identifying the origin of samples than unsupervised principal component analysis(PCA).LDA and OPLS-DA had a mean identification accuracy of 87.84 and 94.64%in the testing set,respectively.By using the multilayer perceptron(MLP)and C5.0,the prediction accuracy of the models could reach 96.36 and 91.06%,respectively.Based on the above four chemometric methods,Cd,Tl,Mo and Se were selected as the main variables and principal markers for the origin identification of winter jujube.Overall,this study demonstrates that it is practical and precise to identify the origin of winter jujube through multi-element fingerprint analysis with chemometrics,and may also provide reference for establishing the origin traceability system of other fruits.展开更多
The first part of the paper summarizes the performance of two mould devices,illustrating by representative shrinkage tendency results in ductile cast iron as affected by mould rigidity(green and furan resin sand mould...The first part of the paper summarizes the performance of two mould devices,illustrating by representative shrinkage tendency results in ductile cast iron as affected by mould rigidity(green and furan resin sand moulds)and inoculant type(FeSi-based alloys).Less rigid green sand moulds encourage the formation of contraction defects,not only because of the high initial expansion values(ε(di))(max),but also because of the increased solidification undercooling.A high inoculation efficiency means not only lowering the carbides formation sensitivity and increasing the nodule count,but also a prolonged graphitization through to the end of the eutectic freezing,as observed by the high population of small late forming nodules,which leads to minimizing the tendency for shrinkage.The second part of the paper illustrates an application of this equipment to commercial foundry use.It conducts thermal analysis and volume change measurements in a single ceramic cup with cast iron quality as a variable.La-bearing FeSi inoculant appears to be more effective than RE(Rare Earth)-FeSi alloy in FeSiMgCa treated irons(no RE),in terms of reducing eutectic undercooling and(ε(di))(max),favourable for lower sensitivity to shrinkage formation.Experiments also compared solidification patterns for white[WI],grey[GI]and ductile[DI]irons,to correlate the most important events between the cooling curves and contraction curves,to evaluate the sensitivity to shrinkage formation.All of the irons have similar values for initial expansion up to the start of eutectic freezing,but,after that,the graphite formation promotes expansion(more than 5 times for nodular graphite),resulting in a difference in maximum expansion(2 times higher for DI).The graphitic expansion has two contrary effects.Increased graphitic expansion(force)leads to a higher shrinkage sensitivity during the first part of the eutectic reaction,but also to a decrease of shrinkage at the end of solidification,due to forcing the last liquid iron to occupy the previous formed cavities.Consequently,strong graphitization process promotion at the end of solidification favours the castings'soundness.展开更多
UV Spectrophotometric Target Factor Analysis (TFA) was used for the simultaneous determination of four components (acetaminophen, guuaifenesin, caffeine, Chlorphenamine maleate) in cough syrup. The computer Frogra...UV Spectrophotometric Target Factor Analysis (TFA) was used for the simultaneous determination of four components (acetaminophen, guuaifenesin, caffeine, Chlorphenamine maleate) in cough syrup. The computer Frogram of TFA is based on VC++ language. The difficulty of overlapping of absorption spectra of four compounds was overcome by this procedure. The experimental results show that the average recovery of each component is all in the range from 98.9% to 106.8% and each component obtains satisfactory results without any pre-separation.展开更多
A factor analysis was applied to soil geochemical data to define anomalies related to buried Pb-Zn mineralization.A favorable main factor with a strong association of the elements Zn,Cu and Pb,related to mineralizatio...A factor analysis was applied to soil geochemical data to define anomalies related to buried Pb-Zn mineralization.A favorable main factor with a strong association of the elements Zn,Cu and Pb,related to mineralization,was selected for interpretation.The median+2 MAD(median absolute deviation)method of exploratory data analysis(EDA)and C-A(concentration-area)fractal modeling were then applied to the Mahalanobis distance,as defined by Zn,Cu and Pb from the factor analysis to set the thresholds for defining multi-element anomalies.As a result,the median+2 MAD method more successfully identified the Pb-Zn mineralization than the C-A fractal model.The soil anomaly identified by the median+2 MAD method on the Mahalanobis distances defined by three principal elements(Zn,Cu and Pb)rather than thirteen elements(Co,Zn,Cu,V,Mo,Ni,Cr,Mn,Pb,Ba,Sr,Zr and Ti)was the more favorable reflection of the ore body.The identified soil geochemical anomalies were compared with the in situ economic Pb-Zn ore bodies for validation.The results showed that the median+2 MAD approach is capable of mapping both strong and weak geochemical anomalies related to buried Pb-Zn mineralization,which is therefore useful at the reconnaissance drilling stage.展开更多
Nowadays,simultaneous interpreting(SI) plays a prominent role in global communications,especially for important international affairs.This kind of interpretation delivers information in an instantaneous way without wa...Nowadays,simultaneous interpreting(SI) plays a prominent role in global communications,especially for important international affairs.This kind of interpretation delivers information in an instantaneous way without wasting extra time for language processing.Performing well in SI requires long-time training and abundant experience.Making a comprehensive categorization and analysis on the difficulties in SI on the basis of psycho-linguistic theories are the key points.Due to the distinctive features of these difficulties,corresponding suggestions will be offered to improve the efficiency in SI training and to level up the performance of SI interpreters.展开更多
Objective: To study the safety and efficacy of concurrent bilateral total knee arthroplasty orstaged bilateral total knee replacement using meta-analysis. Methods: The databases of ChinaWanfang, CNKI, PubMed, Cochrane...Objective: To study the safety and efficacy of concurrent bilateral total knee arthroplasty orstaged bilateral total knee replacement using meta-analysis. Methods: The databases of ChinaWanfang, CNKI, PubMed, Cochrane Library, and Web of Science were searched conducted formeta-analysis of the extracted data using Review Manager 5.3 software. Results: ①A total of 18retrospective cohort studies were included, 72 831 patients in the same period group and 103595 patients in the staging group. ②The results of meta showed that in the staging group, theincidence of postoperative cardiac complications[OR= 1.21, 95%CI=(1.10~1.34), P<0.000 1] ,neurological complications[OR=1.67, 95%CI=(1.29~2.16), P<0.000 1], deep vein thrombosis[OR=1.38, 95%CI(1.27~1.50), P<0.000 01], mortality[OR=2.18, 95%CI=(1.67~2.84),P<0.000 01] and perioperative blood loss [OR=246.75, 95%CI=(233.30~260.20)] were lessthan those in the same period group (P<0.000 01);The postoperative deep infection rate in thesame period group [OR=0.61, 95%CI=(0.52~0.71), P<0.000 01] was lower than that in thestaging group;The postoperative superficial infection rate [OR=0.96, 95%CI=(0.66~1.40)],revision rate of joint replacement [OR= 1.04, 95%CI=( 0.96~1.12)], HSS score [OR=0.10,95%CI=(-0.61~0.80), P=0.79] and knee joint activity score [OR=-0.23, 95%CI=(-1.25~0.78)]were not statistically significant between the two groups(P>0.05).Conclusion: Stagingbilateral total knee replacement can more effectively reduce the incidence of perioperativecomplications and reduce the amount of blood transfusion, while concurrent bilateral total kneereplacement can reduce the rate of deep infection. To further compare the efficacy and safety ofconcurrent or staged bilateral total knee arthroplasty, further studies must be conducted in theform of a randomized clinical trial to evaluate the results mentioned in this meta-analysis.展开更多
The single phase La2(CO3)3·3.4H2 O was synthesized by hydrothermal method. The thermal decomposition and intermediates and final solid products of La2(CO3)3·3.4H2O from 30 to 1000 °C were characteri...The single phase La2(CO3)3·3.4H2 O was synthesized by hydrothermal method. The thermal decomposition and intermediates and final solid products of La2(CO3)3·3.4H2O from 30 to 1000 °C were characterized by XRD, FTIR and DTA-TG. The kinetics of dehydration of La2(CO3)3·3.4H2O in the temperature range of 30-366 °C was investigated under non-isothermal conditions. Flynn-Wall-Ozawa and Friedman isoconversion methods were used to calculate the activation energy and analyze the reaction steps; multivariate non-linear regression program was applied to determine the most probable mechanism and the kinetic parameters. The results show that the thermal dehydration of La2(CO3)3·3.4H2O is a kind of three-step competitive reaction, and controlled by an n-order initial reaction followed by n-order competitive reaction(FnFnFn model). The activation energy matching with the most probable model is close to value obtained by Friedman method. The fitting curves match the original TG-DTG curves very well.展开更多
The configuration and the reference frame of the four-axis wire-electric discharge machining (WEDM) machine tool are introduced. Based on the motion analysis of the four-axis WEDM machine tool, an algorithm for cont...The configuration and the reference frame of the four-axis wire-electric discharge machining (WEDM) machine tool are introduced. Based on the motion analysis of the four-axis WEDM machine tool, an algorithm for controlling the four-axis motion is proposed. The algorithm is applicable to both the invariable and variable taper machining. Motion loci of the machining platform and the wire guiding head are deduced by the algorithm according to the bottom surface locus of the workpiece and the taper angle. The algorithm is used in the CNC system of the four-axis WEDM machine tool and confirmed to be effective.展开更多
A method was developed for content determination of Na, Mg, A1, Si, P,S, C1, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Nb, Zr, Y, Sr, Rb, Ba, La and Ce etc. covering 26 major, minor, and trace elements in marine sedim...A method was developed for content determination of Na, Mg, A1, Si, P,S, C1, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Nb, Zr, Y, Sr, Rb, Ba, La and Ce etc. covering 26 major, minor, and trace elements in marine sediment samples using fused glass disc by X-ray Fluorescence spectrometry. Calibration was made using marine sediment certified reference materials and the synthetic standard samples prepared by mixing several marine sediments with stream sediment and carbonate standard samples in different proportions. The matrix effect was corrected using theoretical alpha coefficients, experience coefficients and the scattered radiation as the internal standard (for the trace elements). The accuracy of the method was evaluated by analysis of certified reference materials GBW07314, GBW07334 and GSMS6. The results are in good agreement with the certified values of the standards with RSD less than 2.60%, except for Y, Cr, Ga, Ce, La, Nb, Rb, and V with RSD less than 9.0% (n=12).展开更多
A very simple, non-destructive, inexpensive and green strategy was applied for the simultaneous determination of ibu-profen (IBP) and paracetamol (PC) using transmission Fourier Transform Infrared (FTIR) spectroscopy ...A very simple, non-destructive, inexpensive and green strategy was applied for the simultaneous determination of ibu-profen (IBP) and paracetamol (PC) using transmission Fourier Transform Infrared (FTIR) spectroscopy in tablet formulations for routine quality control laboratories. For the determination of the active pharmaceutical ingredients (API), KBr pellets containing known amount of standards and samples were used for acquisition of the FTIR spectra. The partial least squares (PLS) calibration model was developed using the spectral region from 1781 - 1683 cm-1 for IBP and 1630 - 1530 cm-1 for PC. The excellent coefficients of determination (R2), 0.9999 and 0.9998 were achieved for IBP and PC, respectively. The accuracy of calibration model was also verified through root mean square error of cross validation (RMSECV) which was found to be 0.064. This work clearly shows the capability of transmission FTIR spectroscopy for assessment of exact quantity of API to control the quality of finished products as well as during processing in pharmaceutical industries without involvement of any solvent.展开更多
A process evaluation system for pulsed gas metal arc welding (GMAW-P) based on the Lab V1EW platform has been developed. This system is comprised of two modules, a simultaneous display module and a data analysis mod...A process evaluation system for pulsed gas metal arc welding (GMAW-P) based on the Lab V1EW platform has been developed. This system is comprised of two modules, a simultaneous display module and a data analysis module. Using these modules, the system can not only provide a comprehensive direct viewing display of the welding electric signal and high speed camera photo, but also can analyze the characteristic parameters of the welding process. The results show that the system works properly.展开更多
This paper proposes an adaptive sliding mode observer(ASMO)-based approach for wind turbines subject to simultaneous faults in sensors and actuators.The proposed approach enables the simultaneous detection of actuator...This paper proposes an adaptive sliding mode observer(ASMO)-based approach for wind turbines subject to simultaneous faults in sensors and actuators.The proposed approach enables the simultaneous detection of actuator and sensor faults without the need for any redundant hardware components.Additionally,wind speed variations are considered as unknown disturbances,thus eliminating the need for accurate measurement or estimation.The proposed ASMO enables the accurate estimation and reconstruction of the descriptor states and disturbances.The proposed design implements the principle of separation to enable the use of the nominal controller during faulty conditions.Fault tolerance is achieved by implementing a signal correction scheme to recover the nominal behavior.The performance of the proposed approach is validated using a 4.8 MW wind turbine benchmark model subject to various faults.Monte-Carlo analysis is also carried out to further evaluate the reliability and robustness of the proposed approach in the presence of measurement errors.Simplicity,ease of implementation and the decoupling property are among the positive features of the proposed approach.展开更多
Traditional distributed denial of service(DDoS)detection methods need a lot of computing resource,and many of them which are based on single element have high missing rate and false alarm rate.In order to solve the pr...Traditional distributed denial of service(DDoS)detection methods need a lot of computing resource,and many of them which are based on single element have high missing rate and false alarm rate.In order to solve the problems,this paper proposes a DDoS attack information fusion method based on CNN for multi-element data.Firstly,according to the distribution,concentration and high traffic abruptness of DDoS attacks,this paper defines six features which are respectively obtained from the elements of source IP address,destination IP address,source port,destination port,packet size and the number of IP packets.Then,we propose feature weight calculation algorithm based on principal component analysis to measure the importance of different features in different network environment.The algorithm of weighted multi-element feature fusion proposed in this paper is used to fuse different features,and obtain multi-element fusion feature(MEFF)value.Finally,the DDoS attack information fusion classification model is established by using convolutional neural network and support vector machine respectively based on the MEFF time series.Experimental results show that the information fusion method proposed can effectively fuse multi-element data,reduce the missing rate and total error rate,memory resource consumption,running time,and improve the detection rate.展开更多
A highly sensitive, selective, and precise ultra-performance liquid chromatography tandem mass spectrometry method was developed and validated for simultaneous quantification of itraconazole and hydroxy itraconazole i...A highly sensitive, selective, and precise ultra-performance liquid chromatography tandem mass spectrometry method was developed and validated for simultaneous quantification of itraconazole and hydroxy itraconazole in human plasma by a single liquid-liquid extraction step. The precursor to product ion transitions of m/z 705.3/392.3, m/z 721.2/408.3 and m/z 708.2/435.4 were used to detect and quantify itraconazole, hydroxy itraconazole and itraconazole-d3 respectively. The lower limit of quantitation was found to be 0.500 ng/mL for itraconazole and 1.00 ng/mL for hydroxy itraconazole. The mean recoveries for itraconazole and hydroxy itraconazole were found to be 100.045% and 100.021%, respectively. This developed method with a chromatographic run time of 2.0 min was successfully applied to a bioequivalence study of 100 mg itraconazole capsule.展开更多
This article attempts to develop a simultaneous optimization procedure of several response variables from incomplete multi-response experiments. In incomplete multi-response experiments all the responses (p) are not r...This article attempts to develop a simultaneous optimization procedure of several response variables from incomplete multi-response experiments. In incomplete multi-response experiments all the responses (p) are not recorded from all the experimental units (n). Two situations of multi-response experiments considered are (i) on units all the responses are recorded while on units a subset of responses is recorded and (ii) on units all the responses (p) are recorded, on units a subset of responses is recorded and on units the remaining subset of responses is recorded. The procedure of estimation of parameters from linear multi-response models for incomplete multi-response experiments has been developed for both the situations. It has been shown that the parameter estimates are consistent and asymptotically unbiased. Using these parameter estimates, simultaneous optimization of incomplete multi-response experiments is attempted following the generalized distance criterion [1]. For the implementation of these procedures, SAS codes have been developed for both complete (k ≤ 5, p = 5) and incomplete (k ≤ 5, p1 = 2, 3 and p2 = 2, 3, where k is the number of factors) multi-response experiments. The procedure developed is illustrated with the help of a real data set.展开更多
Thermodynamic diagrams of Na−S−Fe−H_(2)O system were constructed to analyze the behavior of sulfur and iron in the Bayer process.After digestion,iron mainly exists as Fe_(3)O_(4) and Fe_(2)O_(3) in red mud,and partial...Thermodynamic diagrams of Na−S−Fe−H_(2)O system were constructed to analyze the behavior of sulfur and iron in the Bayer process.After digestion,iron mainly exists as Fe_(3)O_(4) and Fe_(2)O_(3) in red mud,and partial iron transfers into solution as Fe(OH)_(3)^(−),HFeO_(2)^(−),Fe(OH)_(4)^(−)and Fe(OH)_(4)^(2−).The dominant species of sulfur is S^(2−),followed by SO_(4)^(2−),and then SO_(3)^(2−)and S_(2)O_(3)^(2−).The thermodynamic analysis is consistent with the iron and sulfur species distribution in the solution obtained by experiments.When the temperature decreases,sulfur and iron can combine and precipitate.Controlling low potential and reducing temperature are beneficial to removing them from the solution.XRD patterns show that NaFeS_(2)·2H_(2)O,FeS and FeS_(2) widely appear in red mud and precipitates of pyrite and high-sulfur bauxite digestion solution.Thermodynamic analysis can be utilized to guide the simultaneous removal of sulfur and iron in the Bayer process.展开更多
dual-standard addition method was proposed and the principle of simultaneous determination for a interfering binary mixtures was discussed. The proposed procedure was applied to spectroscopic analyses for the simultan...dual-standard addition method was proposed and the principle of simultaneous determination for a interfering binary mixtures was discussed. The proposed procedure was applied to spectroscopic analyses for the simultaneous determination of uranium and thorium without prior separation. Various molar ratios of uranium/thorium, from 0.5∶1 to 10∶1, can be determined with satisfactory precision and accuracy. Uranium and thorium content in a phosphate ore and simulated sample were determined, the recoveries were 98.4%~102.5% for uranium and 96.8%~102.3% for thorium, the relative standard deviations (R.S.D) were 1.5%~2.3% for uranium and 2.1%~3.1% for thorium.展开更多
The thermal decompositions of Ca-bentonites (CaB) from Santai ,Shichuan Province, China over the temperature rage of 30-1100℃ were investigated by simultaneous thermal analyzer. Non-isothermal Kinetic analysis were e...The thermal decompositions of Ca-bentonites (CaB) from Santai ,Shichuan Province, China over the temperature rage of 30-1100℃ were investigated by simultaneous thermal analyzer. Non-isothermal Kinetic analysis were employed to study the thermal decomposition mechanism by using Netzsch Thermokinetics software. The dependence of the activation energy on conversion degree were evaluated by isoconversional methods. The probably mechanism and the corresponding kinetic parameters were determined by multivariate non-linear regression program.展开更多
A high performance liquid chromatographic method was used for the simultaneous identification and qualitative evaluation of 12 bufadienolides(resibufogenin, einobufagin, cinobufaginol, arenobufagin, bufalin, bufotali...A high performance liquid chromatographic method was used for the simultaneous identification and qualitative evaluation of 12 bufadienolides(resibufogenin, einobufagin, cinobufaginol, arenobufagin, bufalin, bufotalin, gamabufotalin, cinobufotalin, ψ-bufaranogin, desacetylcinobufagin, telocinobufagin and resibufogenol) in Venenum Bufonis. The chromatographic separation was performed on a Dikma C18 analytical column via gradient elution with an aqueous solution of acetonitrile and 0.3% acetic acid at a flow rate of 0.8 mL/min. The method was validated to be acceptable in consideration of linearity(r2 〉 0.9992) and recovery(ranged from 98.9% to 102.0%). The limits of detection of the bufadienolides were from 0.48 ng for bufalin to 6.00 ng for cinobufotalin. The intra-day and inter-day precisions of the method were evaluated and were less than 3.0%. The method was successfully used to analyze 19 batches of Venenum Bufonis, and the similarity values between batches were calculated by Similarity Evaluation System for Chromatographic Fingerprint of TCM(Version 2004A, Chinese Pharmacopoeia Committee, Beijing). The results show that the contents of bufadienolides in the medicine and the similarity values based on these bufadienolides varied significantly from batch to batch. This proposed method could be utilized to qualify and control Venenum Bufonis to ensure its safety and efficacy in application.展开更多
Gumiganghwal-tang is a traditional herbal medicine widely used for its anti-inflammatory,analgesic,and antipyretic effects.However,the safety and efficacy of its active ingredients based on an in vivo pharmacokinetic(...Gumiganghwal-tang is a traditional herbal medicine widely used for its anti-inflammatory,analgesic,and antipyretic effects.However,the safety and efficacy of its active ingredients based on an in vivo pharmacokinetic(PK)study have yet been investigated.We have established a sensitive and accurate UPLC-ESI-MS/MS method and conducted a PK study on 14 constituents of Gumiganghwal-tang through human plasma analysis.Analytical conditions were optimized according to the physicochemical properties of the 14 compounds to facilitate efficient separation and eliminate overlap or interference between peaks.KINETEX-C18 and Inertsil-C8 columns were used as UPLC stationary phases,and acetonitrile and aqueous formic acid were used as mobile phases.All the analytes were quantified with a triple quadrupole mass spectrometer using electrospray ionization in multiple reaction monitoring mode.The chromatograms of 14 bioactive compounds showed excellent elution and sensitivity,and each peak was selectively separated and quantified without interference with each other or impurities.The established analytical method was based on international guidelines and was successfully used to perform PK studies of 14 herbal ingredients in humans after oral administration with Gumiganghwal-tang tablets.The oral absorption of most active components of Gumiganghwal-tang was relatively rapid and remained considerably long in the body to be quantified in plasma up to 48 h after administration.展开更多
基金This work was supported by the Scientific Research Foundation for High Level Talents of Qingdao Agricultural University,China(665-1120015)the National Program for Quality and Safety Risk Assessment of Agricultural Products of China(GJFP2019011)the National Natural Science Foundation of China(42207017).
文摘Winter jujube(Ziziphus jujuba'Dongzao')is greatly appreciated by consumers for its excellent quality,but brand infringement frequently occurs in the market.Here,we first determined a total of 38 elements in 167 winter jujube samples from the main winter jujube producing areas of China by inductively coupled plasma mass spectrometer(ICP-MS).As a result,16 elements(Mg,K,Mn,Cu,Zn,Mo,Ba,Be,As,Se,Cd,Sb,Ce,Er,Tl,and Pb)exhibited significant differences in samples from different producing areas.Supervised linear discriminant analysis(LDA)and orthogonal projection to latent structures discriminant analysis(OPLS-DA)showed better performance in identifying the origin of samples than unsupervised principal component analysis(PCA).LDA and OPLS-DA had a mean identification accuracy of 87.84 and 94.64%in the testing set,respectively.By using the multilayer perceptron(MLP)and C5.0,the prediction accuracy of the models could reach 96.36 and 91.06%,respectively.Based on the above four chemometric methods,Cd,Tl,Mo and Se were selected as the main variables and principal markers for the origin identification of winter jujube.Overall,this study demonstrates that it is practical and precise to identify the origin of winter jujube through multi-element fingerprint analysis with chemometrics,and may also provide reference for establishing the origin traceability system of other fruits.
文摘The first part of the paper summarizes the performance of two mould devices,illustrating by representative shrinkage tendency results in ductile cast iron as affected by mould rigidity(green and furan resin sand moulds)and inoculant type(FeSi-based alloys).Less rigid green sand moulds encourage the formation of contraction defects,not only because of the high initial expansion values(ε(di))(max),but also because of the increased solidification undercooling.A high inoculation efficiency means not only lowering the carbides formation sensitivity and increasing the nodule count,but also a prolonged graphitization through to the end of the eutectic freezing,as observed by the high population of small late forming nodules,which leads to minimizing the tendency for shrinkage.The second part of the paper illustrates an application of this equipment to commercial foundry use.It conducts thermal analysis and volume change measurements in a single ceramic cup with cast iron quality as a variable.La-bearing FeSi inoculant appears to be more effective than RE(Rare Earth)-FeSi alloy in FeSiMgCa treated irons(no RE),in terms of reducing eutectic undercooling and(ε(di))(max),favourable for lower sensitivity to shrinkage formation.Experiments also compared solidification patterns for white[WI],grey[GI]and ductile[DI]irons,to correlate the most important events between the cooling curves and contraction curves,to evaluate the sensitivity to shrinkage formation.All of the irons have similar values for initial expansion up to the start of eutectic freezing,but,after that,the graphite formation promotes expansion(more than 5 times for nodular graphite),resulting in a difference in maximum expansion(2 times higher for DI).The graphitic expansion has two contrary effects.Increased graphitic expansion(force)leads to a higher shrinkage sensitivity during the first part of the eutectic reaction,but also to a decrease of shrinkage at the end of solidification,due to forcing the last liquid iron to occupy the previous formed cavities.Consequently,strong graphitization process promotion at the end of solidification favours the castings'soundness.
基金the Science Foundation of Zhejiang Province(No.Y404082)the Science Foundation of Analysis Test of Zhejiang Province(No.03084)
文摘UV Spectrophotometric Target Factor Analysis (TFA) was used for the simultaneous determination of four components (acetaminophen, guuaifenesin, caffeine, Chlorphenamine maleate) in cough syrup. The computer Frogram of TFA is based on VC++ language. The difficulty of overlapping of absorption spectra of four compounds was overcome by this procedure. The experimental results show that the average recovery of each component is all in the range from 98.9% to 106.8% and each component obtains satisfactory results without any pre-separation.
文摘A factor analysis was applied to soil geochemical data to define anomalies related to buried Pb-Zn mineralization.A favorable main factor with a strong association of the elements Zn,Cu and Pb,related to mineralization,was selected for interpretation.The median+2 MAD(median absolute deviation)method of exploratory data analysis(EDA)and C-A(concentration-area)fractal modeling were then applied to the Mahalanobis distance,as defined by Zn,Cu and Pb from the factor analysis to set the thresholds for defining multi-element anomalies.As a result,the median+2 MAD method more successfully identified the Pb-Zn mineralization than the C-A fractal model.The soil anomaly identified by the median+2 MAD method on the Mahalanobis distances defined by three principal elements(Zn,Cu and Pb)rather than thirteen elements(Co,Zn,Cu,V,Mo,Ni,Cr,Mn,Pb,Ba,Sr,Zr and Ti)was the more favorable reflection of the ore body.The identified soil geochemical anomalies were compared with the in situ economic Pb-Zn ore bodies for validation.The results showed that the median+2 MAD approach is capable of mapping both strong and weak geochemical anomalies related to buried Pb-Zn mineralization,which is therefore useful at the reconnaissance drilling stage.
文摘Nowadays,simultaneous interpreting(SI) plays a prominent role in global communications,especially for important international affairs.This kind of interpretation delivers information in an instantaneous way without wasting extra time for language processing.Performing well in SI requires long-time training and abundant experience.Making a comprehensive categorization and analysis on the difficulties in SI on the basis of psycho-linguistic theories are the key points.Due to the distinctive features of these difficulties,corresponding suggestions will be offered to improve the efficiency in SI training and to level up the performance of SI interpreters.
基金Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2019D01C244)。
文摘Objective: To study the safety and efficacy of concurrent bilateral total knee arthroplasty orstaged bilateral total knee replacement using meta-analysis. Methods: The databases of ChinaWanfang, CNKI, PubMed, Cochrane Library, and Web of Science were searched conducted formeta-analysis of the extracted data using Review Manager 5.3 software. Results: ①A total of 18retrospective cohort studies were included, 72 831 patients in the same period group and 103595 patients in the staging group. ②The results of meta showed that in the staging group, theincidence of postoperative cardiac complications[OR= 1.21, 95%CI=(1.10~1.34), P<0.000 1] ,neurological complications[OR=1.67, 95%CI=(1.29~2.16), P<0.000 1], deep vein thrombosis[OR=1.38, 95%CI(1.27~1.50), P<0.000 01], mortality[OR=2.18, 95%CI=(1.67~2.84),P<0.000 01] and perioperative blood loss [OR=246.75, 95%CI=(233.30~260.20)] were lessthan those in the same period group (P<0.000 01);The postoperative deep infection rate in thesame period group [OR=0.61, 95%CI=(0.52~0.71), P<0.000 01] was lower than that in thestaging group;The postoperative superficial infection rate [OR=0.96, 95%CI=(0.66~1.40)],revision rate of joint replacement [OR= 1.04, 95%CI=( 0.96~1.12)], HSS score [OR=0.10,95%CI=(-0.61~0.80), P=0.79] and knee joint activity score [OR=-0.23, 95%CI=(-1.25~0.78)]were not statistically significant between the two groups(P>0.05).Conclusion: Stagingbilateral total knee replacement can more effectively reduce the incidence of perioperativecomplications and reduce the amount of blood transfusion, while concurrent bilateral total kneereplacement can reduce the rate of deep infection. To further compare the efficacy and safety ofconcurrent or staged bilateral total knee arthroplasty, further studies must be conducted in theform of a randomized clinical trial to evaluate the results mentioned in this meta-analysis.
基金Project(201011005-5)supported by the National Land and Resources Public Welfare Scientific Research Project of ChinaProject(41030426)supported by the National Natural Science Foundation of China+1 种基金Project(20095122110015)supported by Specialized Research Fund for the Doctoral Program of Higher Education of ChinaProject(2010-32)supported by Scientific Research Foundation of the Education Ministry for Returned Chinese Scholars,China
文摘The single phase La2(CO3)3·3.4H2 O was synthesized by hydrothermal method. The thermal decomposition and intermediates and final solid products of La2(CO3)3·3.4H2O from 30 to 1000 °C were characterized by XRD, FTIR and DTA-TG. The kinetics of dehydration of La2(CO3)3·3.4H2O in the temperature range of 30-366 °C was investigated under non-isothermal conditions. Flynn-Wall-Ozawa and Friedman isoconversion methods were used to calculate the activation energy and analyze the reaction steps; multivariate non-linear regression program was applied to determine the most probable mechanism and the kinetic parameters. The results show that the thermal dehydration of La2(CO3)3·3.4H2O is a kind of three-step competitive reaction, and controlled by an n-order initial reaction followed by n-order competitive reaction(FnFnFn model). The activation energy matching with the most probable model is close to value obtained by Friedman method. The fitting curves match the original TG-DTG curves very well.
文摘The configuration and the reference frame of the four-axis wire-electric discharge machining (WEDM) machine tool are introduced. Based on the motion analysis of the four-axis WEDM machine tool, an algorithm for controlling the four-axis motion is proposed. The algorithm is applicable to both the invariable and variable taper machining. Motion loci of the machining platform and the wire guiding head are deduced by the algorithm according to the bottom surface locus of the workpiece and the taper angle. The algorithm is used in the CNC system of the four-axis WEDM machine tool and confirmed to be effective.
基金Supported by China Ministry of Science and Technology (2000DEB20081)China Ocean Mineral Resources R&D Association (COMRA) (No.DY105-05-01-05)+1 种基金China Ministry of Education(No.205089)China National Natural Science Foundation (No.40076015)
文摘A method was developed for content determination of Na, Mg, A1, Si, P,S, C1, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Nb, Zr, Y, Sr, Rb, Ba, La and Ce etc. covering 26 major, minor, and trace elements in marine sediment samples using fused glass disc by X-ray Fluorescence spectrometry. Calibration was made using marine sediment certified reference materials and the synthetic standard samples prepared by mixing several marine sediments with stream sediment and carbonate standard samples in different proportions. The matrix effect was corrected using theoretical alpha coefficients, experience coefficients and the scattered radiation as the internal standard (for the trace elements). The accuracy of the method was evaluated by analysis of certified reference materials GBW07314, GBW07334 and GSMS6. The results are in good agreement with the certified values of the standards with RSD less than 2.60%, except for Y, Cr, Ga, Ce, La, Nb, Rb, and V with RSD less than 9.0% (n=12).
文摘A very simple, non-destructive, inexpensive and green strategy was applied for the simultaneous determination of ibu-profen (IBP) and paracetamol (PC) using transmission Fourier Transform Infrared (FTIR) spectroscopy in tablet formulations for routine quality control laboratories. For the determination of the active pharmaceutical ingredients (API), KBr pellets containing known amount of standards and samples were used for acquisition of the FTIR spectra. The partial least squares (PLS) calibration model was developed using the spectral region from 1781 - 1683 cm-1 for IBP and 1630 - 1530 cm-1 for PC. The excellent coefficients of determination (R2), 0.9999 and 0.9998 were achieved for IBP and PC, respectively. The accuracy of calibration model was also verified through root mean square error of cross validation (RMSECV) which was found to be 0.064. This work clearly shows the capability of transmission FTIR spectroscopy for assessment of exact quantity of API to control the quality of finished products as well as during processing in pharmaceutical industries without involvement of any solvent.
文摘A process evaluation system for pulsed gas metal arc welding (GMAW-P) based on the Lab V1EW platform has been developed. This system is comprised of two modules, a simultaneous display module and a data analysis module. Using these modules, the system can not only provide a comprehensive direct viewing display of the welding electric signal and high speed camera photo, but also can analyze the characteristic parameters of the welding process. The results show that the system works properly.
文摘This paper proposes an adaptive sliding mode observer(ASMO)-based approach for wind turbines subject to simultaneous faults in sensors and actuators.The proposed approach enables the simultaneous detection of actuator and sensor faults without the need for any redundant hardware components.Additionally,wind speed variations are considered as unknown disturbances,thus eliminating the need for accurate measurement or estimation.The proposed ASMO enables the accurate estimation and reconstruction of the descriptor states and disturbances.The proposed design implements the principle of separation to enable the use of the nominal controller during faulty conditions.Fault tolerance is achieved by implementing a signal correction scheme to recover the nominal behavior.The performance of the proposed approach is validated using a 4.8 MW wind turbine benchmark model subject to various faults.Monte-Carlo analysis is also carried out to further evaluate the reliability and robustness of the proposed approach in the presence of measurement errors.Simplicity,ease of implementation and the decoupling property are among the positive features of the proposed approach.
基金This work was supported by the Hainan Provincial Natural Science Foundation of China[2018CXTD333,617048]National Natural Science Foundation of China[61762033,61702539]+1 种基金Hainan University Doctor Start Fund Project[kyqd1328]Hainan University Youth Fund Project[qnjj1444].
文摘Traditional distributed denial of service(DDoS)detection methods need a lot of computing resource,and many of them which are based on single element have high missing rate and false alarm rate.In order to solve the problems,this paper proposes a DDoS attack information fusion method based on CNN for multi-element data.Firstly,according to the distribution,concentration and high traffic abruptness of DDoS attacks,this paper defines six features which are respectively obtained from the elements of source IP address,destination IP address,source port,destination port,packet size and the number of IP packets.Then,we propose feature weight calculation algorithm based on principal component analysis to measure the importance of different features in different network environment.The algorithm of weighted multi-element feature fusion proposed in this paper is used to fuse different features,and obtain multi-element fusion feature(MEFF)value.Finally,the DDoS attack information fusion classification model is established by using convolutional neural network and support vector machine respectively based on the MEFF time series.Experimental results show that the information fusion method proposed can effectively fuse multi-element data,reduce the missing rate and total error rate,memory resource consumption,running time,and improve the detection rate.
文摘A highly sensitive, selective, and precise ultra-performance liquid chromatography tandem mass spectrometry method was developed and validated for simultaneous quantification of itraconazole and hydroxy itraconazole in human plasma by a single liquid-liquid extraction step. The precursor to product ion transitions of m/z 705.3/392.3, m/z 721.2/408.3 and m/z 708.2/435.4 were used to detect and quantify itraconazole, hydroxy itraconazole and itraconazole-d3 respectively. The lower limit of quantitation was found to be 0.500 ng/mL for itraconazole and 1.00 ng/mL for hydroxy itraconazole. The mean recoveries for itraconazole and hydroxy itraconazole were found to be 100.045% and 100.021%, respectively. This developed method with a chromatographic run time of 2.0 min was successfully applied to a bioequivalence study of 100 mg itraconazole capsule.
文摘This article attempts to develop a simultaneous optimization procedure of several response variables from incomplete multi-response experiments. In incomplete multi-response experiments all the responses (p) are not recorded from all the experimental units (n). Two situations of multi-response experiments considered are (i) on units all the responses are recorded while on units a subset of responses is recorded and (ii) on units all the responses (p) are recorded, on units a subset of responses is recorded and on units the remaining subset of responses is recorded. The procedure of estimation of parameters from linear multi-response models for incomplete multi-response experiments has been developed for both the situations. It has been shown that the parameter estimates are consistent and asymptotically unbiased. Using these parameter estimates, simultaneous optimization of incomplete multi-response experiments is attempted following the generalized distance criterion [1]. For the implementation of these procedures, SAS codes have been developed for both complete (k ≤ 5, p = 5) and incomplete (k ≤ 5, p1 = 2, 3 and p2 = 2, 3, where k is the number of factors) multi-response experiments. The procedure developed is illustrated with the help of a real data set.
基金the financial supports from the National Natural Science Foundation of China(No.51904052)the Chongqing Research Program of Basic Research and Frontier Technology,China(No.cstc2020jcyjmsxm X0476)+1 种基金the Science and Technology Research Program of Chongqing Municipal Education Commission,China(No.KJQN201901508)the Graduate Science and Technology Innovation Training Program of Chongqing University of Science and Technology,China(No.YKJCX2020201)。
文摘Thermodynamic diagrams of Na−S−Fe−H_(2)O system were constructed to analyze the behavior of sulfur and iron in the Bayer process.After digestion,iron mainly exists as Fe_(3)O_(4) and Fe_(2)O_(3) in red mud,and partial iron transfers into solution as Fe(OH)_(3)^(−),HFeO_(2)^(−),Fe(OH)_(4)^(−)and Fe(OH)_(4)^(2−).The dominant species of sulfur is S^(2−),followed by SO_(4)^(2−),and then SO_(3)^(2−)and S_(2)O_(3)^(2−).The thermodynamic analysis is consistent with the iron and sulfur species distribution in the solution obtained by experiments.When the temperature decreases,sulfur and iron can combine and precipitate.Controlling low potential and reducing temperature are beneficial to removing them from the solution.XRD patterns show that NaFeS_(2)·2H_(2)O,FeS and FeS_(2) widely appear in red mud and precipitates of pyrite and high-sulfur bauxite digestion solution.Thermodynamic analysis can be utilized to guide the simultaneous removal of sulfur and iron in the Bayer process.
文摘dual-standard addition method was proposed and the principle of simultaneous determination for a interfering binary mixtures was discussed. The proposed procedure was applied to spectroscopic analyses for the simultaneous determination of uranium and thorium without prior separation. Various molar ratios of uranium/thorium, from 0.5∶1 to 10∶1, can be determined with satisfactory precision and accuracy. Uranium and thorium content in a phosphate ore and simulated sample were determined, the recoveries were 98.4%~102.5% for uranium and 96.8%~102.3% for thorium, the relative standard deviations (R.S.D) were 1.5%~2.3% for uranium and 2.1%~3.1% for thorium.
文摘The thermal decompositions of Ca-bentonites (CaB) from Santai ,Shichuan Province, China over the temperature rage of 30-1100℃ were investigated by simultaneous thermal analyzer. Non-isothermal Kinetic analysis were employed to study the thermal decomposition mechanism by using Netzsch Thermokinetics software. The dependence of the activation energy on conversion degree were evaluated by isoconversional methods. The probably mechanism and the corresponding kinetic parameters were determined by multivariate non-linear regression program.
基金Supported by the National Basic Researeh Program of China(No.2007CB507400)the National High Technology Research and Development Program(No.2006AA02Z338)+1 种基金Program for Changjiang Scholars and Innovative Research Team in Universities of China(PCSIRT)Partly Supported by the Scientific Foundation of Shanghai City,China(Nos.05DZ19733,06DZ19717,06DZ19005)
文摘A high performance liquid chromatographic method was used for the simultaneous identification and qualitative evaluation of 12 bufadienolides(resibufogenin, einobufagin, cinobufaginol, arenobufagin, bufalin, bufotalin, gamabufotalin, cinobufotalin, ψ-bufaranogin, desacetylcinobufagin, telocinobufagin and resibufogenol) in Venenum Bufonis. The chromatographic separation was performed on a Dikma C18 analytical column via gradient elution with an aqueous solution of acetonitrile and 0.3% acetic acid at a flow rate of 0.8 mL/min. The method was validated to be acceptable in consideration of linearity(r2 〉 0.9992) and recovery(ranged from 98.9% to 102.0%). The limits of detection of the bufadienolides were from 0.48 ng for bufalin to 6.00 ng for cinobufotalin. The intra-day and inter-day precisions of the method were evaluated and were less than 3.0%. The method was successfully used to analyze 19 batches of Venenum Bufonis, and the similarity values between batches were calculated by Similarity Evaluation System for Chromatographic Fingerprint of TCM(Version 2004A, Chinese Pharmacopoeia Committee, Beijing). The results show that the contents of bufadienolides in the medicine and the similarity values based on these bufadienolides varied significantly from batch to batch. This proposed method could be utilized to qualify and control Venenum Bufonis to ensure its safety and efficacy in application.
基金supported by a grant from the National Development Institute of Korean Medicine(NIKOM)funded by the Korean Ministry of Health and Welfare(MOHW),Republic of Korea。
文摘Gumiganghwal-tang is a traditional herbal medicine widely used for its anti-inflammatory,analgesic,and antipyretic effects.However,the safety and efficacy of its active ingredients based on an in vivo pharmacokinetic(PK)study have yet been investigated.We have established a sensitive and accurate UPLC-ESI-MS/MS method and conducted a PK study on 14 constituents of Gumiganghwal-tang through human plasma analysis.Analytical conditions were optimized according to the physicochemical properties of the 14 compounds to facilitate efficient separation and eliminate overlap or interference between peaks.KINETEX-C18 and Inertsil-C8 columns were used as UPLC stationary phases,and acetonitrile and aqueous formic acid were used as mobile phases.All the analytes were quantified with a triple quadrupole mass spectrometer using electrospray ionization in multiple reaction monitoring mode.The chromatograms of 14 bioactive compounds showed excellent elution and sensitivity,and each peak was selectively separated and quantified without interference with each other or impurities.The established analytical method was based on international guidelines and was successfully used to perform PK studies of 14 herbal ingredients in humans after oral administration with Gumiganghwal-tang tablets.The oral absorption of most active components of Gumiganghwal-tang was relatively rapid and remained considerably long in the body to be quantified in plasma up to 48 h after administration.