WO2002002847A1 - Activation of a cathode - Google Patents
Activation of a cathode Download PDFInfo
- Publication number
- WO2002002847A1 WO2002002847A1 PCT/SE2001/001447 SE0101447W WO0202847A1 WO 2002002847 A1 WO2002002847 A1 WO 2002002847A1 SE 0101447 W SE0101447 W SE 0101447W WO 0202847 A1 WO0202847 A1 WO 0202847A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- cathode
- electrocatalytic
- solution
- coating solution
- acid
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
- C23C18/31—Coating with metals
- C23C18/42—Coating with noble metals
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
- C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
- C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
- C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
- C25B11/075—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound
- C25B11/081—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound the element being a noble metal
Definitions
- the present invention relates to a method for activating a cathode suitable for activation on site at a production plant.
- the invention also relates to the use of the activated cathode in an electrolytic cell producing chlorine and alkali metal hydroxide.
- Electrodes are commonly, when in operation, immersed in an electrolyte in an electrolytic cell where chemical products are produced by way of oxidation and reduction reactions of reactants present in the electrolyte.
- the reduction reactions take place at the cathode where reduction products are obtained.
- the oxidation reactions take place at the anode where oxidation products are obtained.
- the electrodes will become exhausted and deactivated due to various deactivation processes taking place while the electrolytic cells are in operation.
- the electric energy is the most expensive "raw material" in the electrolytic reactions.
- the cathodes are liable to progressive deactivation over time.
- the cathodes are subjected to deposition and precipitation of materials present in the electrolyte and to other deteriorating processes deactivating the cathode.
- the decrease in activity leads to a higher power consumption due to an increased overvoltage.
- US 5 164 062 describes a method for preparing a new cathode comprising coating a cathode substrate of e.g. Ni with palladium and another electrocatalytic metal.
- the pH of the coating solution may be adjusted by an organic acid, e.g. acetic acid, oxalic acid and formic acid, or inorganic acids to maintain the pH below 2.8.
- the activation by this method is not always satisfactorily increased.
- a portion of the active coating solution is wasted in the method described above, because some of the acidic electrocatalytic coating solution is rinsed away from the cathode substrate in order to avoid corrosion of the cathode.
- the rinsing solution that has taken up remaining electrocatalytic material must then be decontaminated from substrate ions, e.g. nickel or other contaminating ions, which also are present on the cathode before the electrocatalytic material can be reused as coating material in an electrocatalytic solution again.
- substrate ions e.g. nickel or other contaminating ions
- Such decontamination procedure may involve several cleaning steps before the electrocatalytic material has been satisfactorily cleaned.
- the present invention intends to solve the above problems.
- the present invention relates to a method of activating a cathode suitable for the production of e.g. chlorine and alkali metal hydroxide.
- a cathode suitable for the production of e.g. chlorine and alkali metal hydroxide.
- activate or activation etc. as used herein encompass both activation of a new electrode, which is to be prepared, and activation of an electrode, which has already been in operation in an electrolytic cell and which may have lost at least some of its initial activity.
- the method comprises at least the following steps:
- the solvent must be able to redissolve any possible precipitated electrocatalytic salts or acids on the cathode originating from the electrocatalytic coating solution.
- the solvent may contain a small amount of electrocatalytic metals dissolved therein, which may originate from a rinsing solution containing remains of an electrocatalytic solution.
- the contacting of the solvent with the cathode is suitably performed by spraying or in any other way putting solvent on the cathode in a suitable amount.
- substantially dry is meant a coated cathode which contains only a small quantity of solution on its surface such that the solution does not substantially flow away from the cathode.
- such quantity ranges from about 0 to about 10 ml/m 2 , preferably from about 0 to about 5 ml/m 2 solution.
- the cathode comprises a substrate of e.g. nickel, cobalt, copper, iron, steel, particularly stainless steel, or alloys or mixtures thereof, preferably nickel.
- the cathode may also comprise remains of an electrocatalytic coating deposited on the substrate, and/or contaminants from an electrolytical process.
- Used cathodes are preferably disassembled from the cells before activation.
- the cathode is welded to a pan.
- the used cathode pan structure i.e. the cathode and the pan, is preferably disassembled and removed from the cell before activation.
- the term "cathode”, where otherwise not stated, will henceforth also signify the cathode pan structure.
- the cathode is cleaned with a cleaning solution comprising at least one acid.
- the pH of the cleaning solution is suitably adjusted by addition of an inorganic acid, e.g. HCI, H 2 SO l HNO 3 , or an organic acid, e.g. oxalic acid or other organic acids, or mixtures thereof, suitably to a pH from about -1 to about 6, preferably from about -1 to about 3.
- the acid reacts with the cathode substrate and is also believed to react with precipitated substances on the substrate and the electrocatalytic coating.
- the cleaning time is not critical and may range from about a few minutes to about 30 minutes or more.
- the temperature during the cleaning is not critical and may be at e.g. room temperature, suitably the temperature ranges from about 0 to about 100 °C, preferably from about 0 to about 35 °C.
- a reducing agent is comprised in the cleaning solution which is believed to prevent corrosion of the cathode and facilitate removal of deactivating precipitates on remaining electrocatalytic coating.
- the reducing agent is also believed to stabilise activated areas of the cathode.
- the reducing agent may be present in the cleaning solution at a concentration of from about 0.5 to about 50 wt%, preferably from about 0.5 to about 10 wt%.
- the reducing agent is suitably selected from alcohols such as isopropyl alcohol or n-pentanol, HCI, H 3 PO 2 , H 3 PO 3 , N 2 H 4 , NH 2 OH, NH 3 , Na 2 S, NaBH 4 , sodium hypophosphite (NaH 2 PO 2 ), dimethylamine borane (CH 3 ) 2 NHBH 3 , or mixtures thereof.
- Preferred reducing agents are selected from HCI, H 3 PO 2 , H 3 PO 3 , N 2 H 4 , NH 2 OH, and NH 3 , and most preferably from HCI.
- the cathode is suitably rinsed and dried.
- the cathode is then contacted with at least one electrocatalytic coating solution, comprising an electrocatalytic metal and preferably a complexing agent.
- electrocatalytic coating solutions e.g. two or more coating solutions
- the coating solutions are suitably contacted with the cathode one after the other, preferably when the previously applied coating solution has dried on the surface of the cathode.
- the electrocatalytic coating solution or solutions are suitably applied by means of painting, rolling or any other plausible method suitable for on-site coating.
- the electrocatalytic coating solution suitably comprises one or several noble metals in the form of salts or acids or the like, selected from the platinum group, e.g. Ru, Rh, Os, Ir, Pd, Pt, Au, Ag, or alloys or mixtures thereof.
- the noble metals can suitably be present in the coating solution at a concentration from about 25 to about 200, preferably from about 50 to about 150 g metal/litre coating solution.
- the electrocatalytic metals are suitably derived from salts or acids of e.g. platinum metals such as hexa chloro platinum acid, platinum metal alcoxi complexing materials, chlorides or the like.
- the coating time of the cathode is not critical and may be for about one hour or more.
- the temperature of the coating solution suitably is room temperature, but may range from about 0 to about 100 °C.
- the coating procedure is suitably carried out within the same temperature range, i.e. 0-100 °C, preferably between 0 and 35 °C.
- a complexing agent may be added to the coating solution preferably in a concentration of from about 100 to about 500, and most preferably from about 350 to about 450 g /litre coating solution. The optionally added complexing agent facilitates the oxidation and reduction reactions taking place when the coating solution is contacted with the substrate.
- the substrate metal of the cathode is spontaneously oxidised to its corresponding ionic form whereas the electrocatalytic metal or metals in the coating solution is reduced from its ionic form to its metallic form thereby forming an electrocatalytic coating on the substrate. It has been found that the complexing agent supports the reduction/oxidation reaction taking place so as to improve the precipitation reaction and the adherence of the electrocatalytic metal to the substrate.
- Suitable complexing agents comprise hypophosphorous acid, sulphurous acid, nitrous acid, alcohols such as glycol, glycerine, acetate, propionate, succinate, hydroxyacetate, ⁇ -hydroxypropionate, aminoacetate, ethylenediamine, ⁇ -aminopropionate, malonate, pyrophosphate, malate, citrate, ammonium salts, EDTA, or mixtures thereof.
- the coated cathode is then allowed to dry so it becomes at least substantially dried, suitably from about 0 to about 10 ml/m 2 , preferably from about 0 to about 5 ml/m 2 .
- the coated cathode is completely dried before it is contacted with the solvent.
- the dried cathode is then contacted with a solvent suitably comprising a reducing agent. It has been surprisingly found that the contacting of the solvent with the cathode results in a lower overpotential, often 10-30 mV lower or more, than a cathode not treated in this manner.
- the solvent may comprise water, suitably in combination with HCI, H 3 PO 2 , H3PO 3 , H 2 O 2 , N 2 H 4 , NH 2 OH, NH 3 , Na 2 S, Na 2 S ⁇ 3,K 2 S ⁇ 3 , alcohols such as isopropyl alcohol, n-pentanol, or mixtures thereof.
- the lower overpotential is considered to be principally due to a higher deposit level of electrocatalytic metals on the activated cathode.
- the concentration of a possible reducing agent in the solvent suitably ranges from about 10 to about 70 wt%, preferably from about 40 to about 50 wt%.
- the temperature during the contacting of the cathode with a solvent suitably ranges from about 8 to about 60 °C, preferably from about 15 to about 35 °C.
- the reaction time during which electrocatalytic metals can precipitate as metals on the cathode suitably is from about 1 to about 60 minutes or until the electrode is completely dried.
- solvent can thereafter again be deposited on the cathode to repeat the precipitation procedure of electrocatalytic metals in case such remains exist on the cathode in the form of salts or acids.
- an amount from about 10 to about 100 ml solvent/m 2 cathode area is contacted with the cathode, preferably from about 50 to about 100 ml solvent/m 2 .
- the activated cathode is then preferably rinsed by a rinsing solution such as water to avoid corrosion, preferably with a basic solution such as NaOH after that the solvent on the cathode has substantially dried.
- a rinsing solution such as water to avoid corrosion
- a basic solution such as NaOH
- the basic rinsing solution has a concentration of e.g. NaOH from about 0.0001 to about 50 wt%, and most preferably from about 0.0001 to about 20 wt%.
- the activated cathodes are usually run in the electrolytic cells until their activity is found to be too low, i.e. at an uneconomically low level. This crucial extent of deactivation can be optimised by a person skilled in the art by estimating the electric energy consumed and the activation costs.
- the used cathodes are preferably disassembled and removed from their cells. Suitably, the reactivation can be performed in connection with replacement of the membranes arranged in the electrolytic cell.
- the present invention also relates to a cathode obtainable by the method as described above.
- the invention further concerns the use of an activated cathode in an electrolytic cell for producing chlorine and alkali metal hydroxide.
- Example 1 A cleaning solution was prepared from concentrated hydrochloric acid (37 wt%) to yield a final concentration of 20 wt% hydrochloric acid.
- the cathode to be activated was contacted with the cleaning solution by means of painting. 50 ml cleaning solution/m 2 geometric cathode area was applied. The solution was then allowed to react during 10 minutes at room temperature (25 °C). The cathode was thereafter rinsed thoroughly with deionised water. Meanwhile, a coating solution of RhCI 3 was prepared by dissolving the rhodium salt in a 20 wt% hydrochloric acid solution, resulting in a final rhodium concentration of 50 g Rh metal/litre coating solution.
- a coating solution of RuCI 3 was prepared by dissolving the Ru salt in another 20 wt% hydrochloric acid solution resulting in a concentration of 50 g Ru metal/litre coating solution.
- the rinsed cathode was allowed to dry in room temperature, whereafter the Rh coating solution was applied thereto in an amount of 50 ml/m 2 geometric cathode area by means of painting. The cathode was then allowed to dry for 1 hour.
- the Ru coating solution was then applied to the Rh coated cathode in an amount of 50 ml/m 2 geometric cathode area.
- the cathode was then dried whereafter an aqueous solution of 50 wt% H PO 2 was painted on the cathode. Thereafter, the cathode was allowed to dry whereupon it was rinsed with water. The cathode obtained showed satisfactory activation.
- Example 2 Two deactivated nickel-based cathode samples P1 and P2 were cleaned by means of painting with a 20wt% hydrochloric acid solution for 5 minutes. The cathode samples were thereafter rinsed with water and thereafter dried. The two samples were both coated with a 40 ml RhCI 3 coating solution having a rhodium content of 150 g/litre /m 2 . The coated samples were then allowed to dry for 1 hour. Unreacted rhodium precipitated during the drying stage and formed rhodium chloride salt on the cathode substrate.
- the P1 sample was gently rinsed with a caustic solution having a pH of 10, whereupon unreacted precipitated rhodium metal salt (RhCI 3 ) and nickel chloride were rinsed off the cathode sample.
- RhCI 3 precipitated rhodium metal salt
- the remaining amount of rhodium on the P1 sample only amounted to a small portion of the initially precipitated rhodium content. This was judged from the rhodium colour the rinsing solution got since the metal was partially washed off.
- the P2 cathode sample was gently sprayed with a 20 wt% hydrochloric acid after the RhCI 3 solution had dried on the sample, whereupon precipitated RhCI 3 was redissolved.
- Electrolytic trials performed involving use of the activated cathodes showed that the cell voltage was 230 mV lower for the P2 cathode than for the P1 cathode when the used electrolytic cell was operated at a current density of 4.7 kA/m 2 .
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electrochemistry (AREA)
- Mechanical Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Electrodes For Compound Or Non-Metal Manufacture (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
- Gas-Filled Discharge Tubes (AREA)
- Cold Cathode And The Manufacture (AREA)
- Solid Thermionic Cathode (AREA)
- Chemically Coating (AREA)
- Secondary Cells (AREA)
Abstract
Description
Claims
Priority Applications (10)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP01944058A EP1297200B1 (en) | 2000-07-06 | 2001-06-25 | Activation of a cathode |
CA002415020A CA2415020C (en) | 2000-07-06 | 2001-06-25 | Activation of a cathode |
BRPI0112203-7A BR0112203B1 (en) | 2000-07-06 | 2001-06-25 | process for activating a cathode. |
JP2002507088A JP3867913B2 (en) | 2000-07-06 | 2001-06-25 | Cathode activation |
AU2001266502A AU2001266502B2 (en) | 2000-07-06 | 2001-06-25 | Activation of a cathode |
AU6650201A AU6650201A (en) | 2000-07-06 | 2001-06-25 | Activation of a cathode |
DE60125763T DE60125763T2 (en) | 2000-07-06 | 2001-06-25 | ACTIVATION OF A CATHODE |
KR1020027017509A KR100546928B1 (en) | 2000-07-06 | 2001-06-25 | Activation of a cathode |
US10/332,048 US7011738B2 (en) | 2000-07-06 | 2001-06-25 | Activation of a cathode |
BG107457A BG107457A (en) | 2000-07-06 | 2003-01-13 | Activation of a cathode |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US21649100P | 2000-07-06 | 2000-07-06 | |
EP00850124 | 2000-07-06 | ||
US60/216,491 | 2000-07-06 | ||
EP00850124.9 | 2000-07-06 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2002002847A1 true WO2002002847A1 (en) | 2002-01-10 |
Family
ID=27741095
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/SE2001/001447 WO2002002847A1 (en) | 2000-07-06 | 2001-06-25 | Activation of a cathode |
Country Status (11)
Country | Link |
---|---|
EP (1) | EP1297200B1 (en) |
JP (1) | JP3867913B2 (en) |
KR (1) | KR100546928B1 (en) |
CN (1) | CN1242099C (en) |
AT (1) | ATE350513T1 (en) |
AU (2) | AU6650201A (en) |
BR (1) | BR0112203B1 (en) |
CA (1) | CA2415020C (en) |
DE (1) | DE60125763T2 (en) |
WO (1) | WO2002002847A1 (en) |
ZA (1) | ZA200300111B (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1939182A1 (en) * | 2006-12-22 | 2008-07-02 | Speedel Experimenta AG | Process for the preparation of (R or S)-2-Alkyl-3-heterocyclyl-1-propanols |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4771467B2 (en) * | 2005-11-17 | 2011-09-14 | 東亞合成株式会社 | Method for producing high purity alkali metal hydroxide |
JPWO2010061766A1 (en) | 2008-11-25 | 2012-04-26 | 株式会社トクヤマ | Method for producing active cathode for electrolysis |
ES2805223T3 (en) * | 2016-03-31 | 2021-02-11 | Siemens Ag | Technique for the activation of anodes in situ by a cathode in an alkaline water electrolytic cell |
JP6672211B2 (en) | 2017-03-21 | 2020-03-25 | 株式会社東芝 | Carbon dioxide electrolysis apparatus and carbon dioxide electrolysis method |
EP3887575A1 (en) | 2018-11-30 | 2021-10-06 | Sedo Engineering SA | Leucodye (such as leucoindigo) as dispersing aid |
US11629418B2 (en) | 2018-11-30 | 2023-04-18 | Sedo Engineering Sa | By-products (impurity) removal |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2074190A (en) * | 1980-04-22 | 1981-10-28 | Johnson Matthey Co Ltd | Improved Electrode |
US5035789A (en) * | 1990-05-29 | 1991-07-30 | The Dow Chemical Company | Electrocatalytic cathodes and methods of preparation |
US5476688A (en) * | 1988-08-29 | 1995-12-19 | Ostolski; Marian J. | Process for the preparation of noble metal coated non-noble metal substrates, coated materials produced in accordance therewith and compositions utilizing the coated materials |
-
2001
- 2001-06-25 EP EP01944058A patent/EP1297200B1/en not_active Expired - Lifetime
- 2001-06-25 AU AU6650201A patent/AU6650201A/en active Pending
- 2001-06-25 KR KR1020027017509A patent/KR100546928B1/en not_active IP Right Cessation
- 2001-06-25 AT AT01944058T patent/ATE350513T1/en not_active IP Right Cessation
- 2001-06-25 BR BRPI0112203-7A patent/BR0112203B1/en not_active IP Right Cessation
- 2001-06-25 CA CA002415020A patent/CA2415020C/en not_active Expired - Fee Related
- 2001-06-25 JP JP2002507088A patent/JP3867913B2/en not_active Expired - Fee Related
- 2001-06-25 CN CNB018123732A patent/CN1242099C/en not_active Expired - Fee Related
- 2001-06-25 DE DE60125763T patent/DE60125763T2/en not_active Expired - Lifetime
- 2001-06-25 AU AU2001266502A patent/AU2001266502B2/en not_active Ceased
- 2001-06-25 WO PCT/SE2001/001447 patent/WO2002002847A1/en active IP Right Grant
-
2003
- 2003-01-06 ZA ZA200300111A patent/ZA200300111B/en unknown
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2074190A (en) * | 1980-04-22 | 1981-10-28 | Johnson Matthey Co Ltd | Improved Electrode |
US5476688A (en) * | 1988-08-29 | 1995-12-19 | Ostolski; Marian J. | Process for the preparation of noble metal coated non-noble metal substrates, coated materials produced in accordance therewith and compositions utilizing the coated materials |
US5035789A (en) * | 1990-05-29 | 1991-07-30 | The Dow Chemical Company | Electrocatalytic cathodes and methods of preparation |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1939182A1 (en) * | 2006-12-22 | 2008-07-02 | Speedel Experimenta AG | Process for the preparation of (R or S)-2-Alkyl-3-heterocyclyl-1-propanols |
Also Published As
Publication number | Publication date |
---|---|
CA2415020A1 (en) | 2002-01-10 |
AU6650201A (en) | 2002-01-14 |
AU2001266502B2 (en) | 2004-05-20 |
DE60125763D1 (en) | 2007-02-15 |
ZA200300111B (en) | 2004-01-21 |
CA2415020C (en) | 2008-06-10 |
ATE350513T1 (en) | 2007-01-15 |
KR20030013453A (en) | 2003-02-14 |
EP1297200A1 (en) | 2003-04-02 |
BR0112203A (en) | 2003-05-13 |
KR100546928B1 (en) | 2006-01-26 |
JP3867913B2 (en) | 2007-01-17 |
BR0112203B1 (en) | 2012-05-15 |
EP1297200B1 (en) | 2007-01-03 |
DE60125763T2 (en) | 2007-10-18 |
CN1440467A (en) | 2003-09-03 |
CN1242099C (en) | 2006-02-15 |
JP2004502035A (en) | 2004-01-22 |
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