CN1978099A - PbTe powde material formation preparing method - Google Patents
PbTe powde material formation preparing method Download PDFInfo
- Publication number
- CN1978099A CN1978099A CNA2005101222113A CN200510122211A CN1978099A CN 1978099 A CN1978099 A CN 1978099A CN A2005101222113 A CNA2005101222113 A CN A2005101222113A CN 200510122211 A CN200510122211 A CN 200510122211A CN 1978099 A CN1978099 A CN 1978099A
- Authority
- CN
- China
- Prior art keywords
- pbte
- furnace
- forming material
- powder preparation
- material powder
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000000463 material Substances 0.000 title claims abstract description 60
- 229910002665 PbTe Inorganic materials 0.000 title claims abstract description 42
- OCGWQDWYSQAFTO-UHFFFAOYSA-N tellanylidenelead Chemical compound [Pb]=[Te] OCGWQDWYSQAFTO-UHFFFAOYSA-N 0.000 title claims abstract description 42
- 238000000034 method Methods 0.000 title claims description 12
- 230000015572 biosynthetic process Effects 0.000 title 1
- 239000000843 powder Substances 0.000 claims abstract description 26
- 238000002360 preparation method Methods 0.000 claims abstract description 20
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 19
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 18
- 239000010439 graphite Substances 0.000 claims abstract description 18
- 238000000137 annealing Methods 0.000 claims abstract description 15
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 11
- 238000004140 cleaning Methods 0.000 claims abstract description 11
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 6
- 239000000956 alloy Substances 0.000 claims abstract description 5
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 5
- 238000000227 grinding Methods 0.000 claims abstract description 5
- 238000010438 heat treatment Methods 0.000 claims abstract description 5
- 238000003723 Smelting Methods 0.000 claims abstract description 4
- 230000006698 induction Effects 0.000 claims abstract description 3
- 238000007731 hot pressing Methods 0.000 claims description 12
- 238000002844 melting Methods 0.000 claims description 8
- 230000008018 melting Effects 0.000 claims description 8
- 239000001257 hydrogen Substances 0.000 claims description 5
- 229910052739 hydrogen Inorganic materials 0.000 claims description 5
- 229910052757 nitrogen Inorganic materials 0.000 claims description 5
- 238000000748 compression moulding Methods 0.000 claims description 4
- 239000012153 distilled water Substances 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 3
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 3
- 239000007789 gas Substances 0.000 claims description 3
- 239000008246 gaseous mixture Substances 0.000 claims description 3
- XMBWDFGMSWQBCA-UHFFFAOYSA-N hydrogen iodide Chemical compound I XMBWDFGMSWQBCA-UHFFFAOYSA-N 0.000 claims description 3
- 238000009413 insulation Methods 0.000 claims description 3
- 238000000465 moulding Methods 0.000 claims description 3
- 230000001681 protective effect Effects 0.000 claims description 3
- 238000005245 sintering Methods 0.000 claims description 3
- 239000010935 stainless steel Substances 0.000 claims description 3
- 229910001220 stainless steel Inorganic materials 0.000 claims description 3
- 229910052714 tellurium Inorganic materials 0.000 claims description 3
- PORWMNRCUJJQNO-UHFFFAOYSA-N tellurium atom Chemical compound [Te] PORWMNRCUJJQNO-UHFFFAOYSA-N 0.000 claims description 3
- 238000010792 warming Methods 0.000 claims description 3
- 238000005303 weighing Methods 0.000 claims description 3
- 238000011010 flushing procedure Methods 0.000 claims description 2
- 238000013467 fragmentation Methods 0.000 claims description 2
- 238000006062 fragmentation reaction Methods 0.000 claims description 2
- 239000003595 mist Substances 0.000 claims description 2
- NICDRCVJGXLKSF-UHFFFAOYSA-N nitric acid;trihydrochloride Chemical compound Cl.Cl.Cl.O[N+]([O-])=O NICDRCVJGXLKSF-UHFFFAOYSA-N 0.000 claims description 2
- 238000001291 vacuum drying Methods 0.000 claims description 2
- 238000003825 pressing Methods 0.000 abstract description 2
- 238000001816 cooling Methods 0.000 abstract 1
- 229910001873 dinitrogen Inorganic materials 0.000 abstract 1
- RQQRAHKHDFPBMC-UHFFFAOYSA-L lead(ii) iodide Chemical compound I[Pb]I RQQRAHKHDFPBMC-UHFFFAOYSA-L 0.000 abstract 1
- 238000007873 sieving Methods 0.000 abstract 1
- 238000005516 engineering process Methods 0.000 description 3
- 230000005619 thermoelectricity Effects 0.000 description 3
- 239000004020 conductor Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 210000000031 electric organ Anatomy 0.000 description 2
- 229910052582 BN Inorganic materials 0.000 description 1
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000004663 powder metallurgy Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000013519 translation Methods 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Landscapes
- Powder Metallurgy (AREA)
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
Abstract
The present invention belongs to a PbTe powder material press-forming preparation method. It is characterized by that it uses mould to make PbTe powder material be press-formed. Its preparation process includes the following steps: (1) according to the formula of PbTe+0.3 (wt)Pb+0.08 (wt)PbI2 weighting materials and placing said materials into a graphite crucible; (2) placing said graphite crucible into a vacuum mid-frequency induction smelting furnace, heating and smelting; (3) using ball grinding mill to pulverize the smelted alloy and sieving; (4), cleaning mould and making high-temperature treatment; (5), placing said mould into a thermal pressure furnace, evacuating, introducing hydrogen gas and nitrogen gas; (6) heating thermal pressure furnace, applying pressure and cooling with furnace; (7) placing the hot-pressed material into an annealing furnace and annealing, taking out so as to obtain the invented formed PbTe material.
Description
Technical field
The invention belongs to thermoelectric material manufacturing technology field, particularly relate to a kind of PbTe forming material powder preparation method.
Background technology
The PbTe thermoelectric material is a kind of excellent material of mutual translation function typical case between heat energy and the electric energy of realizing, volume is little because the electric organ made of this thermoelectric material has, movement-less part, noiselessness, pollution-free, do not have wearing and tearing, outstanding advantage such as reliable, have use value widely; PbTe thermoelectric material processing procedure directly has influence on the performance of PbTe thermoelectric material, and final decision is by the quality of its electric organ of making.
The method of present known compacting PbTe thermoelectric material is the powder metallurgy cold-press method, and its weak point is: pressing process demoulding difficulty, and the crack appears in the PbTe material behind sintering; More space etc. appears in the material internal after the compacting, and this all causes conducting material thermoelectricity performance and mechanical performance to reduce, and directly affects the efficient and the life-span of thermoelectric generator.
Summary of the invention
The present invention provides a kind of PbTe forming material powder preparation method who improves conducting material thermoelectricity performance and mechanical performance for solving problems of the prior art.
The present invention for the technical scheme that solves the technical problem employing that exists in the known technology is: PbTe forming material powder preparation method, select for use and assemble the thermoelectric material hot-press arrangement that has graphite jig, adopt pressure sintering with the compression moulding of PbTe dusty material, be characterized in: the preparation process of PbTe dusty material compression moulding is comprised: (1) preparation PbTe dusty material: selecting purity for use is the pure lead iodide PbI of 99.999% lead, tellurium, tin and top grade
2, according to PbTe+0.3 (wt) Pb+0.08 (wt) PbI
2Formula takes by weighing material and puts into the good black-fead crucible of cleaning; (2) alloy melting: the charge black-fead crucible is put into the vacuum medium frequency induction melting furnace heat melting; (3) fragmentation is sieved: with ball mill molten alloy is pulverized, sieved; (4) mould cleaning: graphite jig is carried out cleaning and high-temperature process in advance; (6) vacuumize inflation: grinding tool is put into hot pressing furnace, vacuumize, charge into the mist of hydrogen and nitrogen; (7) hot pressing: hot pressing furnace heats up, and exerts pressure, and cools off with stove; (8) annealing in process: hot-pressed material is put into annealing furnace annealing, be moulding PbTe material after the taking-up.
The present invention can also take following technical measures to realize: charge black-fead crucible smelting temperature is 950 ℃, is incubated 10 minutes, cools off with stove; Used sieve is 120 orders; With stainless steel brush brush mold inside, use the alcohol swab wiping then, dry; Before the dress mould, at grinding tool surface brush last layer demoulding powder, the PbTe dusty material is put into the graphite jig that assembles, the material upper and lower surface is put the graphite flake of same size; Be evacuated to below the 5.0Pa, the ratio of charging into is that the gaseous mixture 0.02-0.05MPa of 1: 9 hydrogen and nitrogen is as protective gas; Hot pressing furnace is warming up to 750-840 ℃, exerts pressure to be 30-50MPa, and under this temperature and pressure, keeps 15-30 minute, cools off with stove; The annealing furnace annealing temperature is that 650 ℃ of insulations were taken out in 3 hours; Need carry out further cleaning promptly to graphite jig in every month: graphite jig was soaked 24 hours, take out the back distilled water flushing in chloroazotic acid; And heating is boiled; Carry out repeatedly, be PH=7～8 until distilled water; Baking box oven dry, 1000 ℃ of high-temperature process 3～5 hours in vacuum drying oven then.
Advantage and good effect that the present invention has are: because heating can change the plasticity of material, can access desirable density, the thermoelectric material mechanical performance that obtains has significant improvement; And thermoelectric material is under HTHP, spreads between powder particle, melting welding chemical combination, dissolving and physical and chemical process such as crystallization again, improved the thermoelectric property of PbTe material.
Description of drawings
Fig. 1 is a PbTe forming material powder preparation method flow chart of the present invention;
Fig. 2 is PbTe forming material powder preparation facilities semi-section schematic diagram shown in Figure 1 for the present invention prepares.
Label among the figure is respectively: 1. upper holder block; 2. thermocouple; 3. fairlead; 4. upper mold core; 5. interior die sleeve; 6. outer die casing; 7. graphite flake; 8.PbTe material powder; 9. lower mold core; 10. lower cushion block; 11. locating piece.
The specific embodiment
For further understanding summary of the invention of the present invention, characteristics and effect, enumerate following examples now, and conjunction with figs. is described in detail as follows:
Black-fead crucible carries out cleaning and high-temperature process in advance, with stainless steel brush brush crucible inner face, uses the alcohol swab wiping then before each the use, dries.With 99.999% raw material is the pure lead iodide PbI of high purity lead, tellurium, tin and top grade
2, according to PbTe+0.3 (wt) Pb+0.08 (wt) PbI
2Formula is that Φ 40 * 15.5mm is an example by the PbTe scantling, calculates required PbTe powder 160g, and according to proportioning, calculating each constituent content is Pb:99.50g, Te60.98g, pbI
20.128g, take by weighing out each amounts of components and put into the good black-fead crucible of cleaning, put into intermediate frequency furnace, be heated to 950 ℃ of meltings, be incubated 10 minutes, cool off with stove.Use the ball mill comminution of material, cross 120 mesh sieves, become thermoelectric material powder 8.The interior die sleeve 5 that ready two semicircle hollow bodies constitute is put into outer die casing 6, lower mold core 9 is put into die sleeve 5, the graphite jig inner surface is coated with last layer boron nitride powder (BN) or powdered carbon (C) uniformly as separating powder, pad last layer graphite flake 7 on lower mold core 9, the thermoelectric material powder 8 of packing into, fill up last layer graphite flake 7 again, place upper mold core 4 at last, form hot pressing die.Locating piece 11 is placed on the hydraulic column of vacuum hotpressing stove; place lower cushion block 10 successively; the hot pressing die of thermoelectric material powder 8 is housed; fairlead 3; upper holder block 1; in the hole of upper holder block 1 and upper mold core 4, plug thermocouple 2; put into hot pressing furnace; be evacuated to below the 5.0Pa; the ratio of charging into is that the gaseous mixture 0.02-0.05MPa of 1: 9 hydrogen and nitrogen is as protective gas; be warming up to 750-840 ℃ then; exert pressure and be 30-50MPa; and under this temperature and pressure, kept 15-30 minute, cool off with stove; hot-pressed material is put into annealing furnace annealing, and annealing temperature is 650 ℃ of insulations 3 hours.Take out test hot pressed samples performance, the bending strength of hot pressed samples 3mm*4mm*15mm reaches 14.86MPa, and power factor reaches 2.81*10
-3W/mK
2, satisfy the PbTe moulding material of thermoelectric material mechanical performance and thermoelectricity capability.
Claims (8)
1. a PbTe forming material powder preparation method selects for use to assemble the thermoelectric material hot-press arrangement that has graphite jig, adopts pressure sintering with the compression moulding of PbTe dusty material, it is characterized in that: the preparation process of PbTe dusty material compression moulding is comprised:
(1) preparation PbTe dusty material: selecting purity for use is the pure lead iodide PbI of 99.999% lead, tellurium, tin and top grade
2, according to PbTe+0.3 (wt) Pb+0.08 (wt) PbI
2Formula takes by weighing material and puts into the good black-fead crucible of cleaning;
(2) alloy melting: the charge black-fead crucible is put into the vacuum medium frequency induction melting furnace heat melting;
(3) fragmentation is sieved: with ball mill molten alloy is pulverized, sieved;
(4) mould cleaning: graphite jig is carried out cleaning and high-temperature process in advance;
(6) vacuumize inflation: grinding tool is put into hot pressing furnace, vacuumize, charge into the mist of hydrogen and nitrogen;
(7) hot pressing: hot pressing furnace heats up, and exerts pressure, and cools off with stove;
(8) annealing in process: hot-pressed material is put into annealing furnace annealing, be moulding PbTe material after the taking-up.
2. PbTe forming material powder preparation method according to claim 1 is characterized in that: charge black-fead crucible smelting temperature is 950 ℃, is incubated 10 minutes, cools off with stove.
3. PbTe forming material powder preparation method according to claim 1 is characterized in that: used sieve is 120 orders.
4. PbTe forming material powder preparation method according to claim 1 is characterized in that: with stainless steel brush brush mold inside, use the alcohol swab wiping then, dry; Before the dress mould, at grinding tool surface brush last layer demoulding powder, the PbTe dusty material is put into the graphite jig that assembles, the material upper and lower surface is put the graphite flake of same size.
5. PbTe forming material powder preparation method according to claim 1 is characterized in that: be evacuated to below the 5.0Pa, the ratio of charging into is that the gaseous mixture 0.02-0.05MPa of 1: 9 hydrogen and nitrogen is as protective gas.
6. PbTe forming material powder preparation method according to claim 1, it is characterized in that: hot pressing furnace is warming up to 750-840 ℃, exerts pressure to be 30-50MPa, and under this temperature and pressure, keeps 15-30 minute, cools off with stove.
7. PbTe forming material powder preparation method according to claim 1 is characterized in that: the annealing furnace annealing temperature is that 650 ℃ of insulations were taken out in 3 hours.
8. PbTe forming material powder preparation method according to claim 1 is characterized in that: need carry out further cleaning promptly to graphite jig in every month: graphite jig was soaked in chloroazotic acid 24 hours, take out the back distilled water flushing; And heating is boiled; Carry out repeatedly, be PH=7～8 until distilled water; Baking box oven dry, 1000 ℃ of high-temperature process 3～5 hours in vacuum drying oven then.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2005101222113A CN1978099A (en) | 2005-12-07 | 2005-12-07 | PbTe powde material formation preparing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2005101222113A CN1978099A (en) | 2005-12-07 | 2005-12-07 | PbTe powde material formation preparing method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1978099A true CN1978099A (en) | 2007-06-13 |
Family
ID=38129498
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2005101222113A Pending CN1978099A (en) | 2005-12-07 | 2005-12-07 | PbTe powde material formation preparing method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1978099A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102194989A (en) * | 2010-03-18 | 2011-09-21 | 中国科学院上海硅酸盐研究所 | Method for preparing thermoelectric material of ternary diamond structure |
| CN102528033A (en) * | 2010-12-24 | 2012-07-04 | 中国电子科技集团公司第十八研究所 | Preparation method of functional gradient thermoelectric material |
| CN103572228A (en) * | 2012-07-31 | 2014-02-12 | 鑫科材料科技股份有限公司 | Method for manufacturing high vapor pressure chalcogen alloy block |
| CN105057679A (en) * | 2015-09-14 | 2015-11-18 | 太原理工大学 | Method for manufacturing aluminum alloy anode metal plate of aluminum-air battery |
| CN105648258A (en) * | 2016-01-18 | 2016-06-08 | 浙江师范大学 | Method for preparing lead telluride alloy thermoelectric material through melt spinning and inductive hot-pressing |
| CN108015292A (en) * | 2017-11-30 | 2018-05-11 | 清远先导材料有限公司 | A kind of preparation method of GeSbTe series alloy powders |
| CN114477107A (en) * | 2022-01-19 | 2022-05-13 | 深圳热电新能源科技有限公司 | N-type PbTe-based thermoelectric material without nano precipitated phase and preparation method thereof |
-
2005
- 2005-12-07 CN CNA2005101222113A patent/CN1978099A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102194989A (en) * | 2010-03-18 | 2011-09-21 | 中国科学院上海硅酸盐研究所 | Method for preparing thermoelectric material of ternary diamond structure |
| CN102194989B (en) * | 2010-03-18 | 2013-10-02 | 中国科学院上海硅酸盐研究所 | Method for preparing thermoelectric material of ternary diamond structure |
| CN102528033A (en) * | 2010-12-24 | 2012-07-04 | 中国电子科技集团公司第十八研究所 | Preparation method of functional gradient thermoelectric material |
| CN102528033B (en) * | 2010-12-24 | 2014-10-15 | 中国电子科技集团公司第十八研究所 | Preparation method of functional gradient thermoelectric material |
| CN103572228A (en) * | 2012-07-31 | 2014-02-12 | 鑫科材料科技股份有限公司 | Method for manufacturing high vapor pressure chalcogen alloy block |
| CN105057679A (en) * | 2015-09-14 | 2015-11-18 | 太原理工大学 | Method for manufacturing aluminum alloy anode metal plate of aluminum-air battery |
| CN105648258A (en) * | 2016-01-18 | 2016-06-08 | 浙江师范大学 | Method for preparing lead telluride alloy thermoelectric material through melt spinning and inductive hot-pressing |
| CN108015292A (en) * | 2017-11-30 | 2018-05-11 | 清远先导材料有限公司 | A kind of preparation method of GeSbTe series alloy powders |
| CN114477107A (en) * | 2022-01-19 | 2022-05-13 | 深圳热电新能源科技有限公司 | N-type PbTe-based thermoelectric material without nano precipitated phase and preparation method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1978099A (en) | PbTe powde material formation preparing method | |
| CN100377378C (en) | Method for preparing Bi-Sb-Te series thermoelectric material | |
| CN1333093C (en) | Preparation method of bismuth-tollurium base thromoelectric alloy | |
| CN101728279B (en) | Preparation method of high-performance diamond reinforced Al-matrix electronic packaging composite material | |
| CN100489131C (en) | Method for manufacturing difficult-to-form pure rhenium sheet | |
| CN102534278A (en) | Sleeve forging and pressing preparation method of bismuth-telluride-base thermoelectric material | |
| CN102730690B (en) | Al4SiC4 material synthetic method | |
| CN104630527B (en) | A kind of method preparing copper base diamond composite | |
| CN103096529B (en) | There is the manufacture method of the silicon nitride heat generating body of higher reliability and fail safe | |
| CN105695774A (en) | Preparation method for Mg3Sb2-based thermoelectric material | |
| CN102094142B (en) | Method for preparing high silicon-aluminum alloy electronic packaging material through rapid hot press | |
| CN102030556B (en) | Method for preparing diamond/silicon carbide ceramic matrix composite material | |
| CN104894641B (en) | It is a kind of high fine and close（LaxCa1‑x）B6Polycrystalline cathode material and preparation method thereof | |
| CN102218535A (en) | Sintering method for molybdenum product | |
| CN110218924A (en) | A kind of preparation method of high-performance diamond sintered article | |
| CN109627002A (en) | A kind of new method quickly preparing antimony Mg base thermoelectricity material | |
| CN109930019B (en) | Method for preparing high-performance SnTe alloy by microwave rapid heating melting-liquid nitrogen quenching | |
| CN103096528B (en) | Preparation method for silicon nitride heating body | |
| CN102534279B (en) | In situ reaction hot-pressing method for manufacturing intermetallic compound T2 phase alloys | |
| CN113012834A (en) | Preparation method of uranium nitride composite uranium trisilicon two-fuel pellet | |
| CN101338386B (en) | Method for preparing TiNi Sn based thermoelectric compounds | |
| CN110436898A (en) | A kind of preparation method of fabricated in situ titanium aluminium nitrogen and titanium nitride enhanced oxidation aluminium Mechanical Property of Ceramics | |
| CN109087987A (en) | A kind of α-MgAgSb base nano composite thermoelectric materials and preparation method thereof | |
| CN101307392B (en) | Process for preparing CoSb3-based thermoelectric material by combining liquid quenching and spark plasma sintering | |
| CN111334685B (en) | Preparation method of high-density Half-Heusler thermoelectric material and obtained product |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |