The styrene-butadiene-styrene（SBS） modified bitumens with different contents of SBS modifiers are stored in different conditions to study the storage stability of SBS modified bitumen.Mixed-level orthogonal array de...The styrene-butadiene-styrene（SBS） modified bitumens with different contents of SBS modifiers are stored in different conditions to study the storage stability of SBS modified bitumen.Mixed-level orthogonal array design（OAD） is used and factors such as SBS modifier content,storage time,storage temperature and container size are chosen in a mixed-level OAD with an OA16（31×44） matrix.Parameters like the separation softening point difference（the separation difference of the ring and ball softening point of the top and bottom samples） and the average softening point（the arithmetic mean of the softening points of the top and bottom samples） are proposed to evaluate the separation and the ageing of modified bitumen during storage in this experiment,respectively.The results reveal that the separation and the ageing during storage exhibit a complicated variation for storage temperature and time.The separation softening point difference decreases with the storage temperature rising from 20 to 120 ℃ and increases with the temperature exceeding 120 ℃,and the average softening point drops with the storage time being prolonged.Different storage conditions have various effects on the storage stability of SBS modified bitumen.展开更多
Objective Lidamycin （LDM） can be dissociated to an apoprotein （LDP） and an active enediyne chromophore （AE）. The detached AE can reassemble with its LDP-containing fusion protein to endow the latter with potent ...Objective Lidamycin （LDM） can be dissociated to an apoprotein （LDP） and an active enediyne chromophore （AE）. The detached AE can reassemble with its LDP-containing fusion protein to endow the latter with potent antitumor activity. However, the reassembly of AE with LDP is affected by several factors. Our aim was to optimize the assembly efficiency of the AE with a LDP-containing fusion protein and investigate the influence of several factors on the assembly efficacy. Methods A method based on RP-HPLC was developed to analyze the assembly rate, and an orthogonal experimental design L9 （3^4） was used to investigate the effects of temperature, assembly time, pH and molecular ratio of LDP-containing fusion protein to AE on the assembly rate. Furthermore, the determined optimum conditions for the assembly rate of the LDP-containing fusion protein with AE were applied and evaluated. Results A calibration curve based on the LDM micromolar concentration against the peak-area of AE by HPLC was obtained. The order in which individual factors in the orthogonal experiment affected the assembly rate were temperature〉time〉pH〉molar ratio of AE to protein and all were statistically significant （P〈0.01）. The optimal assembly conditions were temperature at 10 ℃, time of 12 h, pH 7.0, and the molar ratio of AE： protein of 5：1. The assembly rate of AE with a LDP-containing fusion protein was improved by 23% after condition optimization. Conclusion The assembly rate of chromophore of lidamycin with its LDP-containing fusion protein was improved after condition optimization by orthogonal design, and the optimal conditions described herein should prove useful for the development of this type of LDP-containing fusion protein.展开更多
The separation of enzymatic hydrolysis products of yeast RNA by ion-pair HPLC was studied.A modified chromatographic response function（MCRF） was proposed to appraise the effectiveness of chromatographic separation.T...The separation of enzymatic hydrolysis products of yeast RNA by ion-pair HPLC was studied.A modified chromatographic response function（MCRF） was proposed to appraise the effectiveness of chromatographic separation.This function takes the number of peaks,resolution and the retention time of the last peak into consideration.It shows advantages for optimization of HPLC separation of complex mixtures.An orthogonal array design was used to separate the hydrolysate of yeast RNA and the optimal chromatographic conditions were obtained.展开更多
As a kind of natural fiber,ramie fiber has distinctive advantages in textile application,but the application is limited due to the traditional degumming mode.Compared with the traditional degumming process,the microbi...As a kind of natural fiber,ramie fiber has distinctive advantages in textile application,but the application is limited due to the traditional degumming mode.Compared with the traditional degumming process,the microbial degumming process has many advantages.To obtain the optimal conditions for degumming ramie with Bacillus subtilis DZ_(5)(BS DZ_(5)),a combined statistical approach of orthogonal array design(OAD)and response surface methodology(RSM)was used.The influences of initial pH of the bacteria medium,culture temperature,shaking speed,degumming time and inoculum size on submerged fermentation degumming were evaluated by using fractional factorial design.The main factors in the analysis were culture temperature,shaking speed and initial pH.The residual gum mass fraction was used as the optimization index,and the optimal conditions for degumming were determined by central composite design and RSM.Thus with only a limited number of experiments,an optimal ramie microbial degumming condition was found as the culture temperature of 40℃,the initial pH in the culture medium of 8.5,the shaking speed of 205 r/min,the degumming time of 96 h and the inoculum size of 5%.After microbial degumming of ramie under the optimal conditions,there was only 10.6%residual gum by mass in the fiber.In addition,the effective degumming of BS DZ_(5)was also confirmed by a scanning electron microscope(SEM).展开更多
A method of constructing orthogonal arrays is presented by Zhang, Lu and Pang in 1999.In this paper,the method is developed by introducing a replacement scheme on the construction of orthogonal arrays ,and some new mi...A method of constructing orthogonal arrays is presented by Zhang, Lu and Pang in 1999.In this paper,the method is developed by introducing a replacement scheme on the construction of orthogonal arrays ,and some new mixed-level orthogonal arrays of run size 36 are constructed.展开更多
This paper proposes a novel algorithm for Two-Dimensional(2D) central Directionof-Arrival(DOA) estimation of incoherently distributed sources. In particular, an orthogonal array structure consisting of two Non-uniform...This paper proposes a novel algorithm for Two-Dimensional(2D) central Directionof-Arrival(DOA) estimation of incoherently distributed sources. In particular, an orthogonal array structure consisting of two Non-uniform Linear Arrays(NLAs) is considered. Based on first-order Taylor series approximation, the Generalized Array Manifold(GAM) model can first be established to separate the central DOAs from the original array manifold. Then, the Hadamard rotational invariance relationships inside the GAMs of two NLAs are identified. With the aid of such relationships, the central elevation and azimuth DOAs can be estimated through a search-free polynomial rooting method. Additionally, a simple parameter pairing of the estimated 2D angular parameters is also accomplished via the Hadamard rotational invariance relationship inside the GAM of the whole array. A secondary but important result is a derivation of closed-form expressions of the Cramer-Rao lower bound. The simulation results show that the proposed algorithm can achieve a remarkably higher precision at less complexity increment compared with the existing low-complexity methods, which benefits from the larger array aperture of the NLAs. Moreover, it requires no priori information about the angular distributed function.展开更多
A study was carried out to examine the possibility for Aspergillus niger strain KBS4 to bioleach metals from sulphide ore with low concentration of arsenic and to optimize the parameters that affect this process by or...A study was carried out to examine the possibility for Aspergillus niger strain KBS4 to bioleach metals from sulphide ore with low concentration of arsenic and to optimize the parameters that affect this process by orthogonal array optimization. Fungal sample was collected, purified and sequenced. The bioleaching process was optimized with L25 Taguchi orthogonal experimental array design. Five factors were investigated and 25 batch bioleaching tests were run at five levels for each factor. The parameters were initial pH, particle size, pulp density, initial inoculums and residence time for bioleaching. The experimental results showed that under optimized leaching conditions: pH 5.5, particle size 180 μm, initial inoculums size 3×10 7 spores per ml, pulp density 15% and residence time of 20 days, the bioleach ability of metals were 63% Fe, 68% Zn, 60% As, 79% Cu and 54% Al. The biosorption of metal ions by fungal biomass might occur during the bioleaching process but it did not hinder the removal of metal ions by bioleaching.展开更多
The strontium ions extracted from the aqueous phase into 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(C_2mimNTf2) with dicyclohexyl-18-crown-6(DCH18C6) was stripped effectively by supercritical CO_2(s...The strontium ions extracted from the aqueous phase into 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(C_2mimNTf2) with dicyclohexyl-18-crown-6(DCH18C6) was stripped effectively by supercritical CO_2(sc-CO_2).Hexafluoroacetylacetone(HFAA)-acetonitrile was found to be an excellent modifier of sc-CO_2 to enhance the stripping efficiency.In the orthogonal array design(OAD),OA_(25)(5~5)matrix was employed to optimize the stripping of Sr(Ⅱ) from the DCH 18C6-C_2mimNTf_2 system.Effects of five experimental factors:temperature,pressure,concentration of HFAA,static and dynamic extraction times as well as each factor at five-levels on the stripping of Sr(Ⅱ) were optimized.The effects of these parameters were treated by the analysis of variance(ANOVA).The results showed that Sr(II) could be nearly 100%extracted from the IL phase at 308 K,30 MPa,40 min of dynamic extraction and 60 mmol·L^(-1) HFAA in acetonitrile,respectively.Finally,the stripping mechanism was studied by ESI-MS.展开更多
Computer experiments require space-filling designs with good low-dimensional projection properties.Strong orthogonal arrays are a type of space-filling design that provides better stratifications in low dimensions tha...Computer experiments require space-filling designs with good low-dimensional projection properties.Strong orthogonal arrays are a type of space-filling design that provides better stratifications in low dimensions than ordinary orthogonal arrays.In this paper,we address the problem of constructing strong orthogonal arrays and column-orthogonal strong orthogonal arrays of strength two plus.Existing methods typically rely on regular designs or specific nonregular designs as base orthogonal arrays,limiting the sizes of the final designs.Instead,we propose two general methods that are easy to implement and applicable to a wide range of base orthogonal arrays.These methods produce space-filling designs that can accommodate a large number of factors,provide significant flexibility in terms of run sizes,and possess appealing low-dimensional projection properties.Therefore,these designs are ideal for computer experiments.展开更多
Space-filling designs are popular for computer experiments.Therein space-filling designs with good two-dimensional projection are preferred as two-factor interactions are more likely to be important than three-or high...Space-filling designs are popular for computer experiments.Therein space-filling designs with good two-dimensional projection are preferred as two-factor interactions are more likely to be important than three-or higher-order interactions in practice.Considering two-dimensional projection,the authors propose a new class of designs called group strong orthogonal arrays.A group strong orthogonal array enjoys attractive two-dimensional space-filling property in the sense that it can be partitioned into groups,where any two columns can achieve stratifications on s^(u_(1))×s^(u_(2))grids for any positive integers u_(1),u_(2) with u_(1)+u_(2)=3,and any two columns from different groups can achieve stratifications on s^(v_(1))×s^(v_(2))grids for any positive integers v_(1),v_(2) with v_(1)+v_(2)=4.Few existing designs enjoy such a.ppealing two-dimensional stratification property in the literature.And the level numbers of the obtained designs can be s^(3)or s^(4).In addition to the attractive stratification property,the proposed designs perform very well under orthogonality and uniform projection criteria,and are flexible in run sizes,rendering them highly suitable for computer experiments.展开更多
Objective:To study the dose-response relationship between different treatment parameters of extra-corporeal shock wave(ESW)and their effects on spasticity in children with cerebral palsy by the orthogonal design and t...Objective:To study the dose-response relationship between different treatment parameters of extra-corporeal shock wave(ESW)and their effects on spasticity in children with cerebral palsy by the orthogonal design and to select the best parameter scheme for clinical efficacy.Methods:From March 2020 to December 2020,80 children with spastic cerebral palsy were randomly divided into eight groups of 10 cases.Patients in each group received ESW with varying wave intensities(A),wave frequencies(B),number of shocks(C),and treatment frequencies(D),which were determined by a 4-factor-2-level orthogonal array design.Modified Ashworth Scale(MAS)and GMFM were scored before and after the study,and the difference during the study was calculated to evaluate the performance of each group.Results:The R-value of DMAS was RA>RD>RC>RB and that of DGMFM was RA>RC>RD>RB.The influence of the two levels for each factor was A1>A2,B2>B1,C2>C1,D2>D1.By the analysis of variance,the differences in factors A,C,and D were statistically significant(P<0.05).The optimal combination of ESW treatment parameters for the spasticity of cerebral palsy was 1.5 bar,10 Hz,2000 times,and twice a week.Conclusion:ESW is an effective treatment for spastic cerebral palsy and is worthy of clinical application.展开更多
Strong orthogonal arrays(SOAs) were recently introduced and studied as a class of spacefilling designs for computer experiments. To surely realize better space-filling properties, SOAs of strength three or higher are ...Strong orthogonal arrays(SOAs) were recently introduced and studied as a class of spacefilling designs for computer experiments. To surely realize better space-filling properties, SOAs of strength three or higher are desirable. In addition, orthogonality is also an important property for designs of computer experiments, because it guarantees that the estimates of the main effects are uncorrelated. This paper first provides a systematic study on the construction of(nearly) orthogonal strength-three SOAs with better space-filling properties. The newly proposed strength-three SOAs enjoy almost the same space-filling properties of strength-four SOAs, and can accommodate much more columns than the latter. Moreover, they are(nearly) orthogonal and flexible in run sizes. The construction methods are straightforward to implement, and their theoretical supports are well established. In addition to the theoretical results, many designs are tabulated for practical needs.展开更多
Duloxetine hydrochloride enteric coated pellets were formulated using fluidized bed.Three separate layers,the drug layer,the barrier layer,and the enteric layer,were coated onto the inert core pellets.The pellets were...Duloxetine hydrochloride enteric coated pellets were formulated using fluidized bed.Three separate layers,the drug layer,the barrier layer,and the enteric layer,were coated onto the inert core pellets.The pellets were optimized with the acid resistance and drug release in simulated intestinal fluid as the process parameters,using the Taguchi L9 orthogonal array.Various other properties,such as surface morphology,bulk and tapped density,Hausner’s ratio,hardness,friability,yield of pellets,moisture content,and particle size distribution,were also studied in the optimized pellets.The concentration of the enteric polymer played a vital role in acid resistance,while the type of enteric polymer affected the drug release in simulated intestinal fluid.In both cases,it was determined that binder polymer concentration was not affected much.The comparisons between the optimized pellets and a market formulation yielded f1 and f2 values within a range of 4–5 and 60–65,respectively.Three month stability studies,conducted at accelerated conditions,showed the optimized pellets to be stable.Taguchi plays an important role in optimizing parameters,and optimization of duloxetine hydrochloride can be achieved with minimal trials.展开更多
Orthogonal arrays (OAs), mixed level or fixed level (asymmetric or symmetric), are useful in the design of various experiments. They are also a fundamental tool in the construction of various combinatorial configurati...Orthogonal arrays (OAs), mixed level or fixed level (asymmetric or symmetric), are useful in the design of various experiments. They are also a fundamental tool in the construction of various combinatorial configurations. In this paper, we establish a general "expansive replacement method" for constructing mixedlevel OAs of an arbitrary strength. As a consequence, a positive answer to the question about orthogonal arrays posed by Hedayat, Sloane and Stufken is given. Some series of mixed level OAs of strength ≥3 are produced.展开更多
A simple and rapid method of ionic liquid based dispersive liquid-liquid microextraction （DLLME） combining with high performance liquid chromatography （HPLC） was developed for the analysis of four toxic anilines i...A simple and rapid method of ionic liquid based dispersive liquid-liquid microextraction （DLLME） combining with high performance liquid chromatography （HPLC） was developed for the analysis of four toxic anilines in flour steamed bread and maize steamed bread. Several possible influential factors such as the type of ionic liquid and disperser solvent, extraction time, sample pH, ionic strength and the volume of ionic liquid and disperser solvent were optimized using single factor experiments and orthogonal array design （OAD） with OA25（54） matrix. Analysis of variance （ANOVA） and percent contribution （PC） were used to investigate the significance of the factors of OAD. Sample pH and ionic strength are statistically demonstrated two chief factors. Under the optimum condition, the method exhibits a good linearity （r2 〉 0.99） over the studied range （50-1000 ng g-l） for anilines. The extraction factors and recoveries for the anilines in two kinds of steamed breads ranged between 34.1%-73.3% and 44.3%-95.3%, respectively. The limit of detections （LODs） and limit of quantitations （LOQs） ranged be- tween 10-15 ng g-1 and 30--45 ng g-1.展开更多
Pairwise key establishment is a fundamental security service in sensor networks; it enables sensor nodes to communicate securely with each other using cryptographic techniques. In order to ensure this security, many a...Pairwise key establishment is a fundamental security service in sensor networks; it enables sensor nodes to communicate securely with each other using cryptographic techniques. In order to ensure this security, many approaches have been proposed recently. One of them is to use key predistribution schemes （KPSs） by means of combinatorial designs. In this paper, we use the Bush＇s construction of orthogonal arrays to present a class of key predistribution schemes for distributed sensor networks. The secure connectivity and resilience of the resulting sensor network are analyzed. This KPS constructed in our paper has some better properties than those of the existing schemes.展开更多
By using the generalized Hadamard product, difference matrix and projection matrices, we present a class of orthogonal projection matrices and related orthogonal arrays of strength two. A new class of orthogonal array...By using the generalized Hadamard product, difference matrix and projection matrices, we present a class of orthogonal projection matrices and related orthogonal arrays of strength two. A new class of orthogonal arrays are constructed.展开更多
This paper considers experimental situations where the interested effects have to be or- thogonal to a set of nonnegligible effects. It is shown that various types of orthogonal arrays with mixed strength are A-optima...This paper considers experimental situations where the interested effects have to be or- thogonal to a set of nonnegligible effects. It is shown that various types of orthogonal arrays with mixed strength are A-optimal for estimating the parameters in ANOVA high dimension model representation. Both cases including interactions or not are considered in the model. In particularly, the estimations of all main effects are A-optimal in a mixed strength （2, 2）3 orthogonal array and the estimations of all main effects and two-factor interactions in G~ x G~ are A-optimal in a mixed strength （2, 2）4 orthogonal array. The properties are also illustrated through a simulation study.展开更多
Objective To establish a rapid and effective supercritical fluid extraction（SFE） and rapid resolution liquid chromatography method coupled with diode-array detector（RRLC-DAD） to quantify the chromones in a species...Objective To establish a rapid and effective supercritical fluid extraction（SFE） and rapid resolution liquid chromatography method coupled with diode-array detector（RRLC-DAD） to quantify the chromones in a species. Methods The effects of four parameters including ethanol concentration（50%-90%）, pressure（25-45 MPa）, temperature（40-60 ℃）, and time（30-90 min） on the chromones yields, namely prim-O-glucosylcimifugin, cimifugin, 5-O-methylvisammioside, and sec-O-glucosylhamaudol, were investigated using SFE system with orthogonal array design（OAD）. Furthermore, the extracts were analyzed using rapid resolution liquid chromatography coupled with diode-array detector（RRLC-DAD） system to confirm the results. Results Under the optimized conditions, i.e., 35 MPa of pressure, 60 ℃ of temperature, 70% ethanol, and 60 min of time, the yields of prim-O-glucosylcimifugin, cimifugin, 5-O-methylvisammioside, sec-O-glucosylhamaudol, and total chromones were 3.514, 0.132, 6.242, 0.342, and 10.231 mg/g, respectively. In comparison with ultrasonic assisted extraction（UAE）, SFE was able to yield a 20.7% increase in the total chromones from Saposhnikoviae Radix. Conclusion SFE is an alternative and promising method to extract chromones from this species, and the established RRLC-DAD method could serve as a rapid and effective method for the identification of chromones from Saposhnikoviae Radix.展开更多
The purpose of this paper is to survey the construction of orthogonal arrays of strength two by using difference sets. Some methods for constructing difference set D(2p.2p,p,2), where p is a prime or a prime power, ar...The purpose of this paper is to survey the construction of orthogonal arrays of strength two by using difference sets. Some methods for constructing difference set D(2p.2p,p,2), where p is a prime or a prime power, are given. It is shown that the Kronecker sum of a difference set D(λ1p, k1, p, 2) and an orthogonal array(λ2p2, k2, p, 2) leads to another orthogonal array (λ1λ2p3 .k1k2+1 ,p, 2). This enables us to construct orthogonal arrays[2p(n+1)、1+2(p+p2 +…+pn),p,2],[4p(n+2),1+2p+4(p2+p3+…+p(n+1)),p, 2],and [8p(n+3),1+2P+4p2+8(p3+p4+…+p(n+2)),p,2]where p is a prime or a prime power.展开更多
基金The National Natural Science Foundation of China (No.51178348)
文摘The styrene-butadiene-styrene（SBS） modified bitumens with different contents of SBS modifiers are stored in different conditions to study the storage stability of SBS modified bitumen.Mixed-level orthogonal array design（OAD） is used and factors such as SBS modifier content,storage time,storage temperature and container size are chosen in a mixed-level OAD with an OA16（31×44） matrix.Parameters like the separation softening point difference（the separation difference of the ring and ball softening point of the top and bottom samples） and the average softening point（the arithmetic mean of the softening points of the top and bottom samples） are proposed to evaluate the separation and the ageing of modified bitumen during storage in this experiment,respectively.The results reveal that the separation and the ageing during storage exhibit a complicated variation for storage temperature and time.The separation softening point difference decreases with the storage temperature rising from 20 to 120 ℃ and increases with the temperature exceeding 120 ℃,and the average softening point drops with the storage time being prolonged.Different storage conditions have various effects on the storage stability of SBS modified bitumen.
基金supported by grants from "Significant new drug development" Science and Technology Major Projects of China (2009ZX09301-003 2009ZX09401-005 2010ZX09401-407)
文摘Objective Lidamycin （LDM） can be dissociated to an apoprotein （LDP） and an active enediyne chromophore （AE）. The detached AE can reassemble with its LDP-containing fusion protein to endow the latter with potent antitumor activity. However, the reassembly of AE with LDP is affected by several factors. Our aim was to optimize the assembly efficiency of the AE with a LDP-containing fusion protein and investigate the influence of several factors on the assembly efficacy. Methods A method based on RP-HPLC was developed to analyze the assembly rate, and an orthogonal experimental design L9 （3^4） was used to investigate the effects of temperature, assembly time, pH and molecular ratio of LDP-containing fusion protein to AE on the assembly rate. Furthermore, the determined optimum conditions for the assembly rate of the LDP-containing fusion protein with AE were applied and evaluated. Results A calibration curve based on the LDM micromolar concentration against the peak-area of AE by HPLC was obtained. The order in which individual factors in the orthogonal experiment affected the assembly rate were temperature〉time〉pH〉molar ratio of AE to protein and all were statistically significant （P〈0.01）. The optimal assembly conditions were temperature at 10 ℃, time of 12 h, pH 7.0, and the molar ratio of AE： protein of 5：1. The assembly rate of AE with a LDP-containing fusion protein was improved by 23% after condition optimization. Conclusion The assembly rate of chromophore of lidamycin with its LDP-containing fusion protein was improved after condition optimization by orthogonal design, and the optimal conditions described herein should prove useful for the development of this type of LDP-containing fusion protein.
文摘The separation of enzymatic hydrolysis products of yeast RNA by ion-pair HPLC was studied.A modified chromatographic response function（MCRF） was proposed to appraise the effectiveness of chromatographic separation.This function takes the number of peaks,resolution and the retention time of the last peak into consideration.It shows advantages for optimization of HPLC separation of complex mixtures.An orthogonal array design was used to separate the hydrolysate of yeast RNA and the optimal chromatographic conditions were obtained.
基金National Natural Science Foundation of China(No.51863020)。
文摘As a kind of natural fiber,ramie fiber has distinctive advantages in textile application,but the application is limited due to the traditional degumming mode.Compared with the traditional degumming process,the microbial degumming process has many advantages.To obtain the optimal conditions for degumming ramie with Bacillus subtilis DZ_(5)(BS DZ_(5)),a combined statistical approach of orthogonal array design(OAD)and response surface methodology(RSM)was used.The influences of initial pH of the bacteria medium,culture temperature,shaking speed,degumming time and inoculum size on submerged fermentation degumming were evaluated by using fractional factorial design.The main factors in the analysis were culture temperature,shaking speed and initial pH.The residual gum mass fraction was used as the optimization index,and the optimal conditions for degumming were determined by central composite design and RSM.Thus with only a limited number of experiments,an optimal ramie microbial degumming condition was found as the culture temperature of 40℃,the initial pH in the culture medium of 8.5,the shaking speed of 205 r/min,the degumming time of 96 h and the inoculum size of 5%.After microbial degumming of ramie under the optimal conditions,there was only 10.6%residual gum by mass in the fiber.In addition,the effective degumming of BS DZ_(5)was also confirmed by a scanning electron microscope(SEM).
基金the National Natural Science Foundation of China(6 9972 0 3 6 ) and Foundation of the National Social Science Plan in China (97BTJ0 0 2 )
文摘A method of constructing orthogonal arrays is presented by Zhang, Lu and Pang in 1999.In this paper,the method is developed by introducing a replacement scheme on the construction of orthogonal arrays ,and some new mixed-level orthogonal arrays of run size 36 are constructed.
基金supported by the National Natural Science Foundation of China(No.61401513)
文摘This paper proposes a novel algorithm for Two-Dimensional(2D) central Directionof-Arrival(DOA) estimation of incoherently distributed sources. In particular, an orthogonal array structure consisting of two Non-uniform Linear Arrays(NLAs) is considered. Based on first-order Taylor series approximation, the Generalized Array Manifold(GAM) model can first be established to separate the central DOAs from the original array manifold. Then, the Hadamard rotational invariance relationships inside the GAMs of two NLAs are identified. With the aid of such relationships, the central elevation and azimuth DOAs can be estimated through a search-free polynomial rooting method. Additionally, a simple parameter pairing of the estimated 2D angular parameters is also accomplished via the Hadamard rotational invariance relationship inside the GAM of the whole array. A secondary but important result is a derivation of closed-form expressions of the Cramer-Rao lower bound. The simulation results show that the proposed algorithm can achieve a remarkably higher precision at less complexity increment compared with the existing low-complexity methods, which benefits from the larger array aperture of the NLAs. Moreover, it requires no priori information about the angular distributed function.
基金Supported by the Program for Changjiang Scholars and Innovative Research Team in University, China (IRT0974)the Higher Education Commission of Pakistan (20-652/R&D/05-43622)
文摘A study was carried out to examine the possibility for Aspergillus niger strain KBS4 to bioleach metals from sulphide ore with low concentration of arsenic and to optimize the parameters that affect this process by orthogonal array optimization. Fungal sample was collected, purified and sequenced. The bioleaching process was optimized with L25 Taguchi orthogonal experimental array design. Five factors were investigated and 25 batch bioleaching tests were run at five levels for each factor. The parameters were initial pH, particle size, pulp density, initial inoculums and residence time for bioleaching. The experimental results showed that under optimized leaching conditions: pH 5.5, particle size 180 μm, initial inoculums size 3×10 7 spores per ml, pulp density 15% and residence time of 20 days, the bioleach ability of metals were 63% Fe, 68% Zn, 60% As, 79% Cu and 54% Al. The biosorption of metal ions by fungal biomass might occur during the bioleaching process but it did not hinder the removal of metal ions by bioleaching.
基金Supported by the National Natural Science Foundation of China(91226112)
文摘The strontium ions extracted from the aqueous phase into 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(C_2mimNTf2) with dicyclohexyl-18-crown-6(DCH18C6) was stripped effectively by supercritical CO_2(sc-CO_2).Hexafluoroacetylacetone(HFAA)-acetonitrile was found to be an excellent modifier of sc-CO_2 to enhance the stripping efficiency.In the orthogonal array design(OAD),OA_(25)(5~5)matrix was employed to optimize the stripping of Sr(Ⅱ) from the DCH 18C6-C_2mimNTf_2 system.Effects of five experimental factors:temperature,pressure,concentration of HFAA,static and dynamic extraction times as well as each factor at five-levels on the stripping of Sr(Ⅱ) were optimized.The effects of these parameters were treated by the analysis of variance(ANOVA).The results showed that Sr(II) could be nearly 100%extracted from the IL phase at 308 K,30 MPa,40 min of dynamic extraction and 60 mmol·L^(-1) HFAA in acetonitrile,respectively.Finally,the stripping mechanism was studied by ESI-MS.
基金supported by the Fundamental Research Funds for the Central Universities(Grant Nos.2023JBMC010 and 2412023YQ003)National Natural Science Foundation of China(Grant Nos.12001036,12271166,11901199 and 12371259)。
文摘Computer experiments require space-filling designs with good low-dimensional projection properties.Strong orthogonal arrays are a type of space-filling design that provides better stratifications in low dimensions than ordinary orthogonal arrays.In this paper,we address the problem of constructing strong orthogonal arrays and column-orthogonal strong orthogonal arrays of strength two plus.Existing methods typically rely on regular designs or specific nonregular designs as base orthogonal arrays,limiting the sizes of the final designs.Instead,we propose two general methods that are easy to implement and applicable to a wide range of base orthogonal arrays.These methods produce space-filling designs that can accommodate a large number of factors,provide significant flexibility in terms of run sizes,and possess appealing low-dimensional projection properties.Therefore,these designs are ideal for computer experiments.
基金supported by the National Natural Science Foundation of China under Grant Nos.12301323,12261011,and 12131001the MOE Project of Key Research Institute of Humanities and Social Sciences under Grant No.22JJD110001。
文摘Space-filling designs are popular for computer experiments.Therein space-filling designs with good two-dimensional projection are preferred as two-factor interactions are more likely to be important than three-or higher-order interactions in practice.Considering two-dimensional projection,the authors propose a new class of designs called group strong orthogonal arrays.A group strong orthogonal array enjoys attractive two-dimensional space-filling property in the sense that it can be partitioned into groups,where any two columns can achieve stratifications on s^(u_(1))×s^(u_(2))grids for any positive integers u_(1),u_(2) with u_(1)+u_(2)=3,and any two columns from different groups can achieve stratifications on s^(v_(1))×s^(v_(2))grids for any positive integers v_(1),v_(2) with v_(1)+v_(2)=4.Few existing designs enjoy such a.ppealing two-dimensional stratification property in the literature.And the level numbers of the obtained designs can be s^(3)or s^(4).In addition to the attractive stratification property,the proposed designs perform very well under orthogonality and uniform projection criteria,and are flexible in run sizes,rendering them highly suitable for computer experiments.
基金supported by Foshan Science and Technology Bureau,GuangDong,China(Grant No.1920001001095).
文摘Objective:To study the dose-response relationship between different treatment parameters of extra-corporeal shock wave(ESW)and their effects on spasticity in children with cerebral palsy by the orthogonal design and to select the best parameter scheme for clinical efficacy.Methods:From March 2020 to December 2020,80 children with spastic cerebral palsy were randomly divided into eight groups of 10 cases.Patients in each group received ESW with varying wave intensities(A),wave frequencies(B),number of shocks(C),and treatment frequencies(D),which were determined by a 4-factor-2-level orthogonal array design.Modified Ashworth Scale(MAS)and GMFM were scored before and after the study,and the difference during the study was calculated to evaluate the performance of each group.Results:The R-value of DMAS was RA>RD>RC>RB and that of DGMFM was RA>RC>RD>RB.The influence of the two levels for each factor was A1>A2,B2>B1,C2>C1,D2>D1.By the analysis of variance,the differences in factors A,C,and D were statistically significant(P<0.05).The optimal combination of ESW treatment parameters for the spasticity of cerebral palsy was 1.5 bar,10 Hz,2000 times,and twice a week.Conclusion:ESW is an effective treatment for spastic cerebral palsy and is worthy of clinical application.
基金supported by the National Natural Science Foundation of China under Grant Nos. 12131001and 12226343the MOE Project of Key Research Institute of Humanities and Social Sciences under Grant No.22JJD110001the National Ten Thousand Talents Program of China。
文摘Strong orthogonal arrays(SOAs) were recently introduced and studied as a class of spacefilling designs for computer experiments. To surely realize better space-filling properties, SOAs of strength three or higher are desirable. In addition, orthogonality is also an important property for designs of computer experiments, because it guarantees that the estimates of the main effects are uncorrelated. This paper first provides a systematic study on the construction of(nearly) orthogonal strength-three SOAs with better space-filling properties. The newly proposed strength-three SOAs enjoy almost the same space-filling properties of strength-four SOAs, and can accommodate much more columns than the latter. Moreover, they are(nearly) orthogonal and flexible in run sizes. The construction methods are straightforward to implement, and their theoretical supports are well established. In addition to the theoretical results, many designs are tabulated for practical needs.
基金supported by the RA Chem Pharma Ltd.,Nacharam,Andhra Pradesh,India,and the G.Pulla Reddy College of Pharmacy,Hyderabad,India.
文摘Duloxetine hydrochloride enteric coated pellets were formulated using fluidized bed.Three separate layers,the drug layer,the barrier layer,and the enteric layer,were coated onto the inert core pellets.The pellets were optimized with the acid resistance and drug release in simulated intestinal fluid as the process parameters,using the Taguchi L9 orthogonal array.Various other properties,such as surface morphology,bulk and tapped density,Hausner’s ratio,hardness,friability,yield of pellets,moisture content,and particle size distribution,were also studied in the optimized pellets.The concentration of the enteric polymer played a vital role in acid resistance,while the type of enteric polymer affected the drug release in simulated intestinal fluid.In both cases,it was determined that binder polymer concentration was not affected much.The comparisons between the optimized pellets and a market formulation yielded f1 and f2 values within a range of 4–5 and 60–65,respectively.Three month stability studies,conducted at accelerated conditions,showed the optimized pellets to be stable.Taguchi plays an important role in optimizing parameters,and optimization of duloxetine hydrochloride can be achieved with minimal trials.
基金supported by National Natural Science Foundation of China (Grant Nos.11271280 and 10831002)
文摘Orthogonal arrays (OAs), mixed level or fixed level (asymmetric or symmetric), are useful in the design of various experiments. They are also a fundamental tool in the construction of various combinatorial configurations. In this paper, we establish a general "expansive replacement method" for constructing mixedlevel OAs of an arbitrary strength. As a consequence, a positive answer to the question about orthogonal arrays posed by Hedayat, Sloane and Stufken is given. Some series of mixed level OAs of strength ≥3 are produced.
基金supported by the National Natural Science Foundation of China (20905073 & 20975105)
文摘A simple and rapid method of ionic liquid based dispersive liquid-liquid microextraction （DLLME） combining with high performance liquid chromatography （HPLC） was developed for the analysis of four toxic anilines in flour steamed bread and maize steamed bread. Several possible influential factors such as the type of ionic liquid and disperser solvent, extraction time, sample pH, ionic strength and the volume of ionic liquid and disperser solvent were optimized using single factor experiments and orthogonal array design （OAD） with OA25（54） matrix. Analysis of variance （ANOVA） and percent contribution （PC） were used to investigate the significance of the factors of OAD. Sample pH and ionic strength are statistically demonstrated two chief factors. Under the optimum condition, the method exhibits a good linearity （r2 〉 0.99） over the studied range （50-1000 ng g-l） for anilines. The extraction factors and recoveries for the anilines in two kinds of steamed breads ranged between 34.1%-73.3% and 44.3%-95.3%, respectively. The limit of detections （LODs） and limit of quantitations （LOQs） ranged be- tween 10-15 ng g-1 and 30--45 ng g-1.
基金supported by the National Natural Science Foundation of China under Grant Nos. 60473017, 90604034and 10771078.
文摘Pairwise key establishment is a fundamental security service in sensor networks; it enables sensor nodes to communicate securely with each other using cryptographic techniques. In order to ensure this security, many approaches have been proposed recently. One of them is to use key predistribution schemes （KPSs） by means of combinatorial designs. In this paper, we use the Bush＇s construction of orthogonal arrays to present a class of key predistribution schemes for distributed sensor networks. The secure connectivity and resilience of the resulting sensor network are analyzed. This KPS constructed in our paper has some better properties than those of the existing schemes.
基金The research is supported by the National Natural Science Foundation of China under Grant No. 10571045University Backbone Teachers Foundation of the Education Department of Henan ProvinceNatural Science Foundation of Henan Province under Grant No. 0411011100.
文摘By using the generalized Hadamard product, difference matrix and projection matrices, we present a class of orthogonal projection matrices and related orthogonal arrays of strength two. A new class of orthogonal arrays are constructed.
基金the National Natural Science Foundation of China under Grant Nos.11171065,11301073the Natural Science Foundation of Jiangsu under Grant No.BK20141326+1 种基金the Research Fund for the Doctoral Program of Higher Education of China under Grant No.20120092110021Scientific Research Foundation of Graduate School of Southeast University under Grant No.YBJJ1444
文摘This paper considers experimental situations where the interested effects have to be or- thogonal to a set of nonnegligible effects. It is shown that various types of orthogonal arrays with mixed strength are A-optimal for estimating the parameters in ANOVA high dimension model representation. Both cases including interactions or not are considered in the model. In particularly, the estimations of all main effects are A-optimal in a mixed strength （2, 2）3 orthogonal array and the estimations of all main effects and two-factor interactions in G~ x G~ are A-optimal in a mixed strength （2, 2）4 orthogonal array. The properties are also illustrated through a simulation study.
基金National Natural Science Foundation of China(Grant No.31300270)the Technology Key Project of Jilin Province(Grant No.20130522048JH)the twelfth five-year science and technology plan project of Jilin Education Department(2015205)
文摘Objective To establish a rapid and effective supercritical fluid extraction（SFE） and rapid resolution liquid chromatography method coupled with diode-array detector（RRLC-DAD） to quantify the chromones in a species. Methods The effects of four parameters including ethanol concentration（50%-90%）, pressure（25-45 MPa）, temperature（40-60 ℃）, and time（30-90 min） on the chromones yields, namely prim-O-glucosylcimifugin, cimifugin, 5-O-methylvisammioside, and sec-O-glucosylhamaudol, were investigated using SFE system with orthogonal array design（OAD）. Furthermore, the extracts were analyzed using rapid resolution liquid chromatography coupled with diode-array detector（RRLC-DAD） system to confirm the results. Results Under the optimized conditions, i.e., 35 MPa of pressure, 60 ℃ of temperature, 70% ethanol, and 60 min of time, the yields of prim-O-glucosylcimifugin, cimifugin, 5-O-methylvisammioside, sec-O-glucosylhamaudol, and total chromones were 3.514, 0.132, 6.242, 0.342, and 10.231 mg/g, respectively. In comparison with ultrasonic assisted extraction（UAE）, SFE was able to yield a 20.7% increase in the total chromones from Saposhnikoviae Radix. Conclusion SFE is an alternative and promising method to extract chromones from this species, and the established RRLC-DAD method could serve as a rapid and effective method for the identification of chromones from Saposhnikoviae Radix.
文摘The purpose of this paper is to survey the construction of orthogonal arrays of strength two by using difference sets. Some methods for constructing difference set D(2p.2p,p,2), where p is a prime or a prime power, are given. It is shown that the Kronecker sum of a difference set D(λ1p, k1, p, 2) and an orthogonal array(λ2p2, k2, p, 2) leads to another orthogonal array (λ1λ2p3 .k1k2+1 ,p, 2). This enables us to construct orthogonal arrays[2p(n+1)、1+2(p+p2 +…+pn),p,2],[4p(n+2),1+2p+4(p2+p3+…+p(n+1)),p, 2],and [8p(n+3),1+2P+4p2+8(p3+p4+…+p(n+2)),p,2]where p is a prime or a prime power.
