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1.
《Electrochemistry communications》2007,9(7):1816-1823
This communication describes the electron transport behaviour of basal plane pyrolytic graphite electrodes (BPPGEs) modified with nickel powder (BPPGE-Ni), single-walled carbon nanotube (BPPGE-SWCNT) and BPPGE-Ni decorated with SWCNT via drop-dry method (BPPGE-Ni-SWCNT). The BPPGE-Ni gave enhanced Faradaic response for the redox probe (Ferricyanide/Ferrocyanide species) and also displayed enhanced electrocatalytic behaviour towards the detection of degradation products of V-type nerve agents, dimethylaminoethanethiol (DMAET) and diethylaminoethanethiol (DEAET) with high sensitivity (∼23 × 10−3 AM−1) and low detection limits (4.0–9.0 μM range). When compared to the notable electrodes and detection protocols reported in the literature, BPPGE-Ni exhibits more promising features required for a simple, highly sensitive, fast and less expensive electrode for the detection of these V-type nerve agents in aqueous solution. The efficient response of the BPPGE-Ni is attributed to the high microscopic surface area of the nickel powder. The poor response of the BPPGE-Ni-SWCNT suggests that nickel impurity in the SWCNT did not show any detectable impact on its electron transfer kinetics. 相似文献
2.
Square-wave voltammetry with the hanging drop mercury electrode as the working electrode was used for the determination of
ultratraces of explosives in aqueous solution. It was shown that the strong pressure dependence of the pneumatically controlled
multimode electrode system of a conventional Metrohm apparatus could be compensated by an additional pressure regulation,
through which the pressure variations could be decreased when switching from deaeration to the static measurements. By using
square-wave voltammetry with this electrode system after this modification the limits of detection for 2,4,6-trinitrotoluene
(TNT) and other TNT-metabolites could be decreased down to 0.2 μg L−1 when using a measurement time of 6 min. Also a simultaneous determination of TNT and hexahydro-1,3,5-trinitro-1,3,5-triazine
(RDX) was shown to be possible over a wide linear range and the detection limits then were 2.2 μg L−1 for TNT and 25 μg L−1 for RDX. By applying the highly stable and adjustable pressure as mentioned before, the calibrations could be kept stable
over a period of up to 1 week. 相似文献
3.
Majid Arvand Maryam Vaziri Mohammad Ali Zanjanchi 《Journal of Solid State Electrochemistry》2012,16(3):1151-1159
Cyclic voltammetry, chronoamperometry, and rotating disk electrode voltammetry were used to investigate the electrochemical
behavior of thiobencarb (TB) at carbon paste electrode modified with an azo dye, 2-(4-((4-ethoxyphenyl)diazenyl)phenylamino)ethanol
(EDPE), EDPE/modified carbon paste electrode (MCPE). The modified electrode showed high electrocatalytic activity toward thiobencarb.
The current was enhanced significantly relative to the situation prevailing when a bare glassy carbon electrode was used.
The kinetics parameters of this process were calculated, the apparent electron transfer rate constant k
s and α (charge transfer coefficient between electrode and EDPE) were 14.6 s−1 and 0.48, respectively. The experimental parameters were optimized, and the mechanism of the catalytic process was discussed.
The best defined cathodic peak was obtained with 0.1 M acetate buffer (pH 3.0). The response of the sensor was very quick,
and response time was approximately 5 s. The differential pulse voltammetry response of the MCPE was linear against the concentration
of TB in the range of 0.96 to 106 μg L−1. The limit of detection was found to be 0.025 μg L−1. The precision was examined by carrying out eight replicate measurements at a concentration of 25 μg L−1 TB; the relative standard deviation was 2.9%. 相似文献
4.
Juliana Canto Duarte Rita de Cássia Silva Luz Flavio Santos Damos Adriano Bof de Oliveira Lauro Tatsuo Kubota 《Journal of Solid State Electrochemistry》2007,11(5):631-638
The electrocatalytical oxidation of hydrazine at low potential using tetracyanoquinodimethanide adsorbed on silica modified
with titanium oxide was investigated by cyclic voltammetry and amperometry. The modified electrode was prepared modifying
a carbon paste electrode employing lithium tetracyanoquinodimethanide adsorbed onto silica gel modified with titanium oxide.
This electrode showed an excellent catalytic activity and stability for hydrazine oxidation. With this modified electrode,
the oxidation potential of hydrazine was shifted toward less positive value, presenting a peak current much higher than those
observed on a bare GC electrode. The linear response range, sensitivity and detection limit were, respectively, 2 up to 100 μmol
l−1, 0.36 μA l μmol−1, and 0.60 μmol l−1. The repeatability of the modified electrode evaluated in term of relative standard deviation was 4.2% for 10 measurements
of 100 μmol l−1 hydrazine solution. The number of electrons involved in hydrazine oxidation (4), the heterogenous electron transfer rate
constant (1.08 × 103 mol−1 l s−1), and diffusion coefficient (5.9 × 10−6 cm2 s−1) were evaluated with a rotating disk electrode. 相似文献
5.
A highly sensitive hydroxylamine (HA) electrochemical sensor is developed based on electrodeposition of gold nanoparticles
with diameter of 8 nm on the pre-synthesized polypyrrole matrix and formed gold nanoparticles/polypyrrole (GNPs/PPy) composite
on glassy carbon electrode. The electrochemical behavior and electrocatalytic activity of the composite-modified electrode
are investigated. The GNPs/PPy composite exhibits a distinctly higher electrocatalytic activity for the oxidation of HA than
GNPs with twofold enhancement of peak current. The enhanced electrocatalytic activity is attributed to the synergic effect
of the highly dispersed gold metal particles and PPy matrix. The overall numbers of electrons involved in HA oxidation, the
electron transfer coefficient, catalytic rate constant, and diffusion coefficient are investigated by chronoamperometry. The
sensor presents two wide linear ranges of 4.5 × 10−7–1.2 × 10−3 M and 1.2 × 10−3–19 × 10−3 M with the detection limit of 4.5 × 10−8 M (s/n = 3). In addition, the proposed electrode shows excellent sensitivity, selectivity, reproducibility, and stability properties. 相似文献
6.
De Souza D de Toledo RA Galli A Salazar-Banda GR Silva MR Garbellini GS Mazo LH Avaca LA Machado SA 《Analytical and bioanalytical chemistry》2007,387(6):2245-2253
The use of a copper solid amalgam electrode (CuSAE) for the analytical determination of triazine herbicides (atrazine and
ametryne) instead of the conventional hanging mercury drop electrode (HMDE) is reported. The results obtained using electroanalytical
methods utilizing each of these electrodes were also compared with those provided by the HPLC technique. The results indicated
that the CuSAE electrode can be used to detect the herbicides studied, since the detection limits reached using the electrode
(3.06 μg L−1 and 3.78 μg L−1 for atrazine and ametryne, respectively) are lower than the maximum values permitted by CONAMA (Brazilian National Council
for the Environment) for wastewaters (50 μg L−1) and by the US EPA (Environmental Protection Agency of the United States) in natural water samples (10.00 μg L−1). An electroanalytical methodology employing CuSAE and square wave voltammetry (SWV) was successfully applied to the determination
of atrazine and ametryne in natural water samples, yielding good recoveries (70.30%–79.40%). This indicates that the CuSAE
provides a convenient substitute for the HMDE, particularly since the CuSAE minimizes the toxic waste residues produced by
the use of mercury in HDME-based analyses. 相似文献
7.
The electrochemical oxidation of thiocytosine on the surface of carbon-paste electrode modified with Schiff base (salophen
derivatives) complexes of cobalt is studied. The effect of the substituents in the structure of salophen on the catalytic
property of the modified electrode is investigated by using cyclic and differential pulse voltammetry. Cobalt (II)-5-nitrosalophen,
because of its electrophilic functional groups, leads to a considerable enhancement in the catalytic activity, sensitivity
(peak current), and a marked increase in the anodic potential of the modified electrode. The differential pulse voltammetry
is applied as a very sensitive method for the detection of thiocytosine. The linear dynamic range was between 1 × 10−3 to 4 × 10−6 M with a slope of 0.0168 μA/μM, and the detection limit was 1 × 10−6 M. The modified electrode is successfully applied for the voltammetric detection of thiocytosine in human synthetic serum
sample and also pharmaceutical preparations. A linear range from 1 × 10−3 to 1 × 10−5 M with a slope of 0.0175 μA/μM is resulted for the standard addition of thiocytosine spiked to the buffered human serum,
which is differing from the curve in buffer solution about 4%. The electrode has a very good reproducibility (relative standard
deviation for the slope of the calibration curve is less than 3.5% based on six determinations in a month), high stability
in its voltammetric response and low detection limit for thiocytosine, and high electrochemical sensitivity with respect to
other biological thiols such as cysteine. 相似文献
8.
Conducting polymer poly(pyrrole) (PPy) doped with Nafion was successfully used as ion-to-electron transducer in the construction
of a solid-contact Pb2+-selective polymeric membrane electrode. The Nafion dopant can effectively increase the capacitance of the conducting polymer
and improve the mechanical robustness of the coating. The transducer layer, PPy-Nafion, characterized by cyclic voltammetry
and electrochemical impedance spectroscopy, exhibits a sufficiently high bulk (redox) capacitance and fast ion and electron
transport process. The new Pb2+-selective polymeric membrane electrode, based on PPy-Nafion film as solid contact, shows stable Nernstian characteristics
in Pb(NO3)2 solution within the concentration range of 1.0 × 10−7–1.0 × 10−3 M, and the detection limit is 4.3 × 10−8 M. The potential stability of the electrode and the influence of the interfacial water layer were also evaluated by chronopotentiometry
and potentiometric water layer test, respectively. The results show that the solid-contact Pb2+-selective electrode, based on PPy-Nafion film as ion-to-electron transducer, can effectively overcome the potential drift
and reduce the water layer between the PPy-Nafion transducer layer and the ion-selective membrane. 相似文献
9.
A very stable electroactive film of catechin was electrochemically deposited on the surface of activated glassy carbon electrode.
The electrochemical behavior of catechin modified glassy carbon electrode (CMGCE) was extensively studied using cyclic voltammetry.
The properties of the electrodeposited films, during preparation under different conditions, and the stability of the deposited
film were examined. The charge transfer coefficient (α) and charge transfer rate constant (k
s) for catechin deposited film were calculated. It was found that the modified electrode exhibited excellent electrocatalytic
activity toward hydrazine oxidation and it also showed a very large decrease in the overpotential for the oxidation of hydrazine.
The CMGCE was employed to study electrocatalytic oxidation of hydrazine using cyclic voltammetry, rotating disk voltammetry,
chronoamperometry, amperometry and square-wave voltammetry as diagnostic techniques. The catalytic rate constant of the modified
electrode for the oxidation of hydrazine was determined by cyclic voltammetry, chronoamperometry and rotating disk voltammetry
and was found to be around 10−3 cm s−1 . In the used different voltammetric methods, the plot of the electrocatalytic current versus hydrazine concentration is
constituted of two linear segments with different ranges of hydrazine concentration. Furthermore, amperometry in stirred solution
exhibits a detection limit of 0.165 μM and the precision of 4.7% for replicate measurements of 40.0 μM solution of hydrazine. 相似文献
10.
Falong Jia Chuanfang Yu Jingming Gong Lizhi Zhang 《Journal of Solid State Electrochemistry》2008,12(12):1567-1571
Prussian blue-modified nanoporous gold film (PB-NPGF) electrode was fabricated in this study. The fabrication was realized
through electrodeposition of Prussian blue nanoparticles on the skeleton of a nanoporous gold film electrode without destroying
the porous structure of NPGF electrode. The resulting PB-NPGF composite electrode showed very high electrocatalytic activity,
repeatability, and stability to the reduction of H2O2. For instance, its activity was about twenty times that of the PB-modified polished gold electrode. More importantly, the
sensitivity of the PB-NPGF composite electrode reaches as high as 10.6 μA μM−1 cm−2. This PB-NPGF composite electrode is very promising in the fields of catalysis, analysis, and so on. 相似文献
11.
Purvi B. Desai Rahul M. Kotkar Ashwini K. Srivastava 《Journal of Solid State Electrochemistry》2008,12(9):1067-1075
The electrochemical behaviour of pyridoxine hydrochloride (pyridoxine HCl) at the plain carbon paste electrode and the electrode
modified with oxa crown ether has been studied using voltammetric and impedance measurements. The macrocycles used as modifiers
were 18-crown-6, dibenzo-18-crown-6 (DB18C6), dicyclohexano-18-crown-6 and dibenzo-24-crown-8, out of which DB18C6 gave better
response for pyridoxine HCl. Tris buffer (pH 10.3) was chosen as an appropriate medium among the several supporting electrolytes
of varying pH studied. The characterization of the DB18C6-modified electrode (CME-DB18C6) using kinetic parameters such as
number of electrons (n) and electron transfer coefficient (α) is studied by cyclic voltammetry. Electrochemical impedance spectroscopic measurements obtained confirm the current enhancement
over the modified electrode. Analytical applications of this electrode have been studied for the determination of pyridoxine
HCl. A sensitive linear working range of 0.6 to 100 μg cm−3 with a detection limit of 0.4 μg cm−3 by differential pulse voltammetry was observed for pyridoxine HCl on CME-DB18C6. However, on decreasing the scan rate to
5 mV s−1, the detection limit lowered to 0.2 μg cm−3. Interference from some vitamins like thiamine hydrochloride, riboflavin, nicotinamide, para-aminobenzoic acid, cyanocobalamin, folic acid and d-biotin and amino acid l-tryptophan was studied, and simultaneously, riboflavin, thiamine hydrochloride and pyridoxine HCl were determined over the
modified electrode, CME-DB18C6. The modified electrode is successfully used for the determination of pyridoxine HCl in multivitamin
pharmaceutical preparations. 相似文献
12.
Abdollah Salimi Zahra Enferadi Abdollah Noorbakhash Kayomars Rashidi 《Journal of Solid State Electrochemistry》2012,16(4):1369-1375
Glassy carbon electrode modified with electrodeposited nickel oxide nanoparticles (NiOxNPs) was used as electrocatalyst for
oxidation of omeprazole and pentoperazole in alkaline solution. The modified electrode exhibited efficient electrocatalytic
activity for the oxidation of omeprazole and pentoperazole with relatively high sensitivity, excellent stability, and long
lifetime. Hydrodynamic amperometric method is used for determination of selected analytes. Under optimized condition, the
linear concentration range, detection limit, and sensitivity of modified electrode toward omeprazole detection are 4.5–120 μM,
0.4 μM (at signal to noise 3), and 40.1 nA μM−1 cm−2, respectively. For pantoperazole, hydrodynamic amperometric determination yielded calibration curve with linear range of
2.5–180 μM, detection limit of 0.2 μM, and sensitivity of 39.2 nA μM−1 cm−2, respectively. The proposed method was successfully applied to pentoperazole and omeprazole determination in drug samples. 相似文献
13.
A new modified electrode was prepared by electrodeposition of caffeic acid (CFA) at the surface of an activated glassy carbon
electrode. Cyclic voltammetry was used to investigate the redox properties of this electrode at various solution pH values
and at various scan rates. The pH dependence of the electrode response was found to be 58.5 mV/pH, which is very close to
the expected Nernstian value. The electrode was also employed to study electrocatalytic oxidation of reduced nicotinamide
adenine dinucleotide (NADH), using cyclic voltammetry, chronoamperometry and rotating disk voltammetry as diagnostic techniques.
It was found that the modified electrode exhibits potent and persistent electrocatalytic properties toward NADH oxidation
in phosphate buffer solution (pH 7.0) with a diminution of the overpotential of about 450 mV compared to the process at an
unmodified electrode. The electrocatalytic current increases linearly with NADH concentration in the range tested from 0.05
to 1.0 mM. The apparent charge transfer rate constant and transfer coefficient for electron transfer between the electrode
surface and immobilized CFA were calculated as 11.2 s−1 and 0.43, respectively. The heterogeneous rate constant for oxidation of NADH at the CFA-modified electrode surface was also
determined and found to be about 3 × 103 M−1 s−1. Finally, the diffusion coefficient of NADH was calculated as 3.24 × 10−6 cm2 s−1 for the experimental conditions, using chronoamperometric results.
Received: 6 January 1999 / Accepted: 11 May 1999 相似文献
14.
A modified glassy carbon (GC) electrode was developed for the amperometric detection of biogenic amines, particularly histamine. The electrode was modified with the co‐enzyme pyrroloquinoline quinone (PQQ) by entrapment during electropolymerziation of pyrrole to form polypyrrole (PPy). This method formed a thin film on the electrode surface possessing very good stability with a shelf‐life exceeding one month without loss of signal. Optimal conditions for the PQQ/PPy electrode were determined and a linear response was found for histamine in phosphate buffer (pH 6) at +550 mV from 40 to 170 mg L?1 with a limit of detection (S/N≥3) of 38 mg L?1. The practical linear range offered by this method suggests ideal use for spoilage detection in fermented foods. 相似文献
15.
Salimi Abollah Noorbakhsh Abdollah Semnani Abolfazl 《Journal of Solid State Electrochemistry》2011,15(9):2041-2052
A simple method was used to fabricate flavin adenine dinucleotide (FAD)/NiOx nanocomposite on the surface of glassy carbon
(GC) electrode. Cyclic voltammetry technique was applied for deposition nickel oxide nanostructures onto GC surface. Owing
to its high biocompatibility and large surface area of nickel oxide nanomaterials with immersing the GC/NiOx-modified electrode
into FAD solution for a short period of time, 10–140 s, a stable thin layer of the FAD molecules immobilized onto electrode
surface. The FAD/NiOx films exhibited a pair of well-defined, stable, and nearly reversible CV peaks at wide pH range (2–10).
The formal potential of adsorbed FAD onto nickel oxide nanoparticles film, E
o′ vs. Ag/AgCl reference electrode is −0.44 V in pH 7 buffer solutions was similar to dissolved FAD and changed linearly with
a slope of 58.6 mV/pH in the pH range 2–10. The surface coverage and heterogeneous electron transfer rate constant (k
s
) of FAD immobilized on NiOx film glassy carbon electrode are 4.66 × 10−11 mol cm−2 and 63 ± 0.1 s−1, indicating the high loading ability of the nickel oxide nanoparticles and great facilitation of the electron transfer between
FAD and nickel oxide nanoparticles. FAD/NiOx nanocomposite-modified GC electrode shows excellent electrocatalytic activity
toward S2O82− reduction at reduced overpotential. Furthermore, rotated modified electrode illustrates good analytical performance for amperometric
detection of S2O82−. Under optimized condition, the concentration calibration range, detection limit, and sensitivity were 3 μM–1.5 mM, 0.38 μM
and 16.6 nA/μM, respectively. 相似文献
16.
Determination of nitrobenzene by differential pulse voltammetry and its application in wastewater analysis 总被引:1,自引:0,他引:1
A new method for the determination of nitrobenzene (NB) by differential pulse voltammetry (DPV) based on an adsorptive stripping
technique was developed. Cyclic voltammetry (CV) was used in a comparative investigation into the electrochemical reduction
of NB at a glassy carbon electrode (GCE). With this electrode, the sharp peak of NB appeared at −0.71 V (vs. Ag/AgCl). The
experimental parameters were optimized. Studies on the effect of pH on the peak height and peak potential were carried out
over the pH range ca. 9.0–11.5 with sodium carbonate/sodium hydrogen carbonate buffer solution. A solution of pH 9.9 was chosen
as analytical medium. Cathodic peak currents were found to be linearly related to the concentration of NB over the range ca.
12.3–1.23 × 104 μg L−1 with relative standard deviations of ca. 3.26–6.75%. The detection limit of NB in water was 5.42 μg L−1. The interference of organic and inorganic species on the voltammetric response was also studied. The proposed method was
applied to the determination of NB in wastewater samples with an average recovery of ca. 95.9–102.4%. 相似文献
17.
M. Mazloum Ardakani A. Talebi H. Naeimi M. Nejati Barzoky N. Taghavinia 《Journal of Solid State Electrochemistry》2009,13(9):1433-1440
A carbon paste electrode, modified with 2, 2′-[1,7-hepthandiylbis(nitriloethylidyne)]-bis-hydroquinone and TiO2 nanoparticles, was used for the simultaneous determination of dopamine (DA), uric acid (UA), and l-cysteine. The study was carried out by using cyclic voltammetry, chronoamperometry, and square wave voltammetry (SWV) techniques.
Some kinetic parameters such as the electron transfer coefficient (α) and heterogeneous rate constant (ks) were also determined for the DA oxidation. A dynamic range of 8.0–1400 μM, with the detection limit of 8.4 × 10−7 M for DA, was obtained using SWV (pH = 7.0). The prepared electrode was successfully applied for the determination of DA,
UA, and l-cysteine in real samples. 相似文献
18.
Rui Rui Zhuang Fang Fang Jian KeFei Wang HaiLian Xiao 《Transition Metal Chemistry》2010,35(3):315-320
The present work reports on the synthesis, characterization and performance of a new cobalt(II) complex, [Co(C10H21-bim)2(SCN)2] (bim = benzimidazole) as electrocatalyst for trichloroacetic acid and bromate reduction. Its structure was characterized
by X-ray crystallography, IR spectroscopy and elemental analysis. The cobalt atom adopts a distorted tetrahedral geometry
by coordinating to four nitrogen atoms from two thiocyanates and two 1-decyl-1H-benzo[d]imidazole ligands. The electrochemical behavior and electrocatalysis of the title complex bulk-modified carbon paste electrode
(Co-CPE) have been studied by cyclic voltammetry. The Co-CPE shows good electrocatalytic activities toward the reduction of
trichloroacetic acid and bromate. The detection limit and the sensitivity are 0.02 μM, 34.63 μA μM−1 for trichloroacetic acid detection, and 0.03 μM, 78.92 μA μM−1 for bromate detection, respectively. This modified electrode shows good reproducibility, high stability, low detection limit,
technical simplicity and possibility of rapid preparation, which is important for practical application. 相似文献
19.
Influence of boric acid on the electrochemical deposition of Ni 总被引:1,自引:0,他引:1
M. Šupicová R. Rozik L. Trnková R. Oriňáková M. Gálová 《Journal of Solid State Electrochemistry》2006,10(2):61-68
The electrolytic deposition of Ni onto a paraffin-impregnated graphite electrode from supporting chloride electrolyte (0.5 mol dm−3 NaCl) adjusted to the required pH using dilute HCl is investigated. The effect of electrolyte composition on the Ni electrodeposition
is studied using linear sweep voltammetry in the cathodic region. An elimination voltammetry procedure was applied to evaluate
the polarization curves. The aim of this work was to deduce the mechanism of Ni reduction in the chloride bath as well as
the influence of boric acid on this. Positively-charged NiCl+ ions were found to be the electroactive particles in the Ni reduction mechanism. The strong competition between the NiCl+, Cl− and H+ ions for active sites at the electrode is discussed. Kinetically-controlled adsorption/desorption processes of various species
were also confirmed using elimination voltammetry with a linear scan. The evolution of gaseous hydrogen, catalyzed by the
freshly-deposited Ni, accompanies the electrodeposition process. The presence of boric acid at a sufficiently high concentration
inhibits the deposition of Ni and, at the same time, improves the morphology and brightness, as well as the adhesion of the
deposited Ni.
Elimination voltammetry with a linear scan is an efficient way to evaluate current–potential curves that reflect the electrodeposition
of one-component Ni coatings. By eliminating selected currents, additional interesting and useful information can be obtained
from voltammetric data. 相似文献
20.
There is an increasing need to assess the harmful effects of heavy-metal-ion pollution on the environment. The ability to
detect and measure toxic contaminants on site using simple, cost effective, and field-portable sensors is an important aspect
of environmental protection and facilitating rapid decision making. A screen-printed gold sensor in a three-electrode configuration
has been developed for analysis of lead(II) by square-wave stripping voltammetry (SWSV). The working electrode was fabricated
with gold ink deposited by use of thick-film technology. Conditions affecting the lead stripping response were characterised
and optimized. Experimental data indicated that chloride ions are important in lead deposition and subsequent analysis with
this type of sensor. A linear concentration range of 10–50 μg L−1 and 25–300 μg L−1 with detection limits of 2 μg L−1 and 5.8 μg L−1 were obtained for lead(II) for measurement times of four and two minutes, respectively. The electrodes can be reused up to
20 times after cleaning with 0.5 mol L−1 sulfuric acid. Interference of other metals with the response to lead were also examined to optimize the sensor response
for analysis of environmental samples. The analytical utility of the sensor was demonstrated by applying the system to a variety
of wastewater and soil sample extracts from polluted sites. The results are sufficient evidence of the feasibility of using
these screen-printed gold electrodes for the determination of lead(II) in wastewater and soil extracts. For comparison purposes
a mercury-film electrode and ICP–MS were used for validation. 相似文献