สถิติ
เปิดเมื่อ28/01/2015
อัพเดท19/06/2024
ผู้เข้าชม2109874
แสดงหน้า2607216
ปฎิทิน
October 2024
Sun Mon Tue Wed Thu Fri Sat
  
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
  
สมาชิก

สมัครสมาชิก | ลืมรหัสผ่าน

ทังสเตนคาร์ไบด์

อ่าน 695854 | ตอบ 8373
ทังสเตนคาร์ไบด์
       ทังสเตนคาร์ไบด์ (อังกฤษ: tungsten carbide) มีสูตรเคมีคือ WC ในรูปพื้นฐานจะมีลักษณะเป็นผงสีเทาละเอียด มี 2 โครงสร้างคือแบบหกเหลี่ยม (α-WC) และแบบลูกบาศก์ (β-WC)
 
       ทังสเตนคาร์ไบด์เตรียมได้จากการทำปฏิกิริยาระหว่างทังสเตนกับคาร์บอนที่อุณหภูมิ 1400–2000 °C[3] หรือให้ความร้อนกับทังสเตนไตรออกไซด์และแกรไฟต์โดยตรงที่ 900 °C หรือในแก๊สไฮโดรเจนที่ 670 °C ตามด้วยการคาร์บิวไรเซชันในแก๊สอาร์กอนที่ 1000 °C[4] หรือใช้วิธีการเคลือบด้วยไอเคมี เช่น
  • ทำปฏิกิริยาระหว่างทังสเตนเฮกซะคลอไรด์กับไฮโดรเจนและมีเทนที่อุณหภูมิ 670 °C (1,238 °F)
 WCl6 + H2 + CH4 WC + 6 HCl
  • ทำปฏิกิริยาระหว่างทังสเตนเฮกซะฟลูออไรด์กับไฮโดรเจนและเมทานอลที่อุณหภูมิ 350 °C (662 °F)
                WF6 + 2 H2 + CH3OH → WC + 6 HF + H2O
       ทังสเตนคาร์ไบด์มีจุดหลอมเหลวที่ 2,870 °C (5,200 °F) และจุดเดือดที่ 6,000 °C (10,830 °F) มีความแข็งระดับ 9 ตามมาตราโมสและประมาณ 2600 ตามมาตราวิกเคอส์[5] ทังสเตนคาร์ไบด์มีความแข็งเกร็งมากกว่าเหล็กกล้าประมาณ 2 เท่า มีค่ามอดุลัสของยังประมาณ 530–700 GPa (77,000–102,000 ksi)[2][6][5][7] โมดูลัสของแรงบีบอัด 630–655 GPa และโมดูลัสของแรงเฉือน 274 GPa[8]
 
ด้วยคุณสมบัติความแข็งและทนความร้อนสูง ทังสเตนคาร์ไบด์จึงใช้ทำเป็นเครื่องมือตัดหรือหัวเจาะ ใช้ทำกระสุนเจาะเกราะ เครื่องมือผ่าตัด อุปกรณ์กีฬา เครื่องประดับและอื่น ๆ
 
 
 
 
 
 
 
 
 
 
อ้างอิง
 
  1. Kurlov, p. 22
  2. Blau, Peter J. (2003). Wear of Materials. Elsevier. p. 1345. ISBN 978-0-08-044301-0.
  3. Pierson, Hugh O. (1992). Handbook of Chemical Vapor Deposition (CVD): Principles, Technology, and Applications. William Andrew Inc. ISBN 0-8155-1300-3.
  4. Zhong, Y.; Shaw, L. (2011). 'A study on the synthesis of nanostructured WC–10 wt% Co particles from WO3 , Co3O4 , and graphite'. Journal of Materials Science 46 (19): 6323–6331. Bibcode:2011JMatS..46.6323Z. doi:10.1007/s10853-010-4937-y.
  5. Groover, Mikell P. (2010). Fundamentals of Modern Manufacturing: Materials, Processes, and Systems. John Wiley & Sons. p. 135. ISBN 978-0-470-46700-8.
  6. Kurlov, p. 3
  7. Cardarelli, François (2008). Materials Handbook: A Concise Desktop Reference. Springer Science & Business Media. pp. 640–. ISBN 978-1-84628-669-8.
  8. Kurlov, pp. 30, 135
  9. Sprince, NL.; Chamberlin, RI.; Hales, CA.; Weber, AL.; Kazemi, H. (1984). 'Respiratory disease in tungsten carbide production workers'. Chest 86 (4): 549–557. PMID 6434250. doi:10.1378/chest.86.4.549.
  10. 12th Report on Carcinogens'. National Toxicology Program. http://ntp.niehs.nih.gov/go/roc12. เรียกข้อมูลเมื่อ 2011-06-24.
ความคิดเห็น :
1661
อ้างอิง

call girls Faridabad
faridabad call girls number $$ faridabad call gril $$ faridabad escort $$  faridabad escort girl $$ faridabad escort girls $$ faridabad escort service $$ faridabad escort services $$ faridabad escorts $$ faridabad escorts service $$ faridabad escorts services $$ faridabad ki call girl $$ faridabad sex girl $$ female escort $$ female escort faridabad $$ female escort in faridabad $$ female escorts $$ female escorts faridabad $$ female escorts in faridabad $$ girls call $$ girls online booking $$ high profile call girl $$ high profile call girls $$ high profile escorts $$ house wife call girl $$ house wife escort service $$ housewife call $$ housewife call girl $$ independent call girl faridabad $$near by call girl $$ near call girl $$ near me call girl $$ near me escort $$ nearby call girl $$ noida call girl $$ old call girls $$ old faridabad call girls $$ online booking call girls $$ online booking girl $$ online call girl $$ online call girl booking $$ online call girls $$ online call girls booking $$ online escort service $$ online girl booking $$ online girls booking $$ rassian call girl $$ russian call girl $$ russian call girl near me $$ russian call girls $$ russian call girls in faridabad $$ russian call girls near me $$ russian escort $$ russian escort service $$ russian escorts in faridabad $$ russian girls escort $$ scort services $$ service girls $$ sex girl contact $$ sex girl in faridabad $$ sex girls in faridabad $$ sex in faridabad $$ sex service $$ sex service in faridabad $$ sex workers in faridabad $$ surajkund call girls $$ एस्कॉर्ट सर्विस फरीदाबाद $$ कॉल गर्ल फरीदाबाद
 
call girls Faridabad [223.235.244.xxx] เมื่อ 14/05/2022 17:44
1662
อ้างอิง

Sonia Chopra
 
ลิงค์ที่เกี่ยวข้อง : https://www.julyroy.com/
Sonia Chopra [223.235.244.xxx] เมื่อ 14/05/2022 19:32
1663
อ้างอิง

Teena Vishwas
I am Teena Vishwas Delhi Independent Girl - an all-natural super fun Independent Delhi fun girl who offers all services. I am a truly stunning model with the personality to match. I am just pure class. I am a mind blower and will have you coming back for sure. A date with me would be a truly unforgettable one. Without doubt I am one of Delhi’s most stunning entertainment girl.
 
ลิงค์ที่เกี่ยวข้อง : https://www.teenavishwas.com
Teena Vishwas [49.36.178.xxx] เมื่อ 15/05/2022 14:37
1664
อ้างอิง

Chhavi Garg
 
ลิงค์ที่เกี่ยวข้อง : https://www.chhavigarg.com
Chhavi Garg [49.36.178.xxx] เมื่อ 15/05/2022 17:46
1665
อ้างอิง

ananyarao
With our best Guwahati escorts services, you are able to create night exceptionally excellent night. Guwahati Escorts Service ' Provides you the best call girls and escort service in Guwahati at a very effective price for more info. Guwahati Call Girls Itanagar Call Girls Shillong Call Girls Imphal Call Girls Aizawl Call Girls Kohima Call Girls Gangtok Call Girls Agartala Call Girls Dispur Call Girls Silchar Call Girls Tezpur Call Girls Sivasagar Call Girls Golaghat Call Girls Dharmanagar Call Girls Leh Call Girls Naharlagun Call Girls Dimapur Call Girls https://haydur-nation.tribe.so/user/guwahatiescorts
https://socialme.tribe.so/user/guwahatiescorts
https://ricardolukas.tribe.so/user/guwahatiescorts
https://udaipurescort.tribe.so/user/guwahatiescorts
https://apsaraofindia.tribe.so/user/guwahatiescorts
https://aadikal.tribe.so/user/guwahatiescorts
https://artiiseoteam.tribe.so/user/guwahatiescorts
https://jennifermitchell.tribe.so/user/guwahatiescorts
https://funboyprojects.tribe.so/user/guwahatiescorts
https://legendarymedia.tribe.so/user/guwahatiescorts
https://socially.tribe.so/user/guwahatiescorts
https://brandonparker.tribe.so/user/guwahatiescorts
https://wisdom.tribe.so/user/guwahatiescorts
https://d-techyinc.com/community/profile/guwahatiescorts/
https://microspace.online/community/profile/guwahatiescorts/
https://vdiscoverconsultancy.com/community/profile/guwahatiescorts/
https://roarmind.com/community/profile/guwahatiescorts/
https://masonintheusa.net/community/profile/guwahatiescorts/
https://anotepad.com/notes/g4nihpkq
https://twinoid.com/user/10047337
http://www.ttunnel.it/community/profile/guwahatiescorts/
https://landoglobalbusiness.com/community/profile/guwahatiescorts/
https://dialoguewithadoptees.org/community/profile/guwahatiescorts/
https://marketplace.tribe.so/user/guwahatiescorts
https://mommavilla.tribe.so/user/guwahatiescorts
 
ลิงค์ที่เกี่ยวข้อง : http://callgirls69.in/
ananyarao [117.98.27.xxx] เมื่อ 15/05/2022 17:52
1666
อ้างอิง

Sonam Sinha

Sonam Sinha Delhi Escorts – Become a Professional New Escorts

Without the learning of how the business functions, it can be an overwhelming background when beginning as a female model. Sonam Sinha Agency is here to offer you some assistance with launching your vocation in demonstrating and raise it as hell free as would be prudent. Sonam Sinha Delhi Escorts has an abundance of industry information which can be attracted on to kick-begin your vocation and place you in the best position to augment your prosperity as a female model.Sonam Sinha Delhi Escorts Agency often gets asked what makes a female model successful. Actually, its vital to have the right look, and to have the capacity to posture and associate with the camera. Be that as it may, what truly separates a model is his or her identity. Certainty is critical; a model arrives to offer an item or thought, and your disposition will do this. Picture takers and planners need to work with models that fill their heart with joy fun. By turning up with the right disposition, you can make yourself emerge from the group.

Considering requesting one of our escorts in Delhi? Call us

Each young ladies representing Sonam Sinha Delhi Escort Agency are sitting tight for an entire night of pleasure with you and needs to shake your reality. Each is appealing, lovely and heavenly, and our young ladies will do astounding things to the man that will arrange them for several minutes or more.Our Delhi escorts are absolutely proficient and calming, as they will unobtrusively go to your lodging room and thump on the entryway exactly at the right minute, when you need them. They shape the excellence world class that is our Delhi escorts organization, and we are extremely pleased with every single one of our young ladies. Would you like some fraternity, go to supper, a gathering, or out on the town with a beguiling lady? At that point you should contact our firm. The administration we give is first rate and we deal with every one of our clients. We ceaselessly endeavour to carry out our employment well and make sure that our supporters are fulfilled. The costs we convey are extremely focused and you will unquestionably get the opportunity to appreciate each moment of your period with our escorts.

Searching for a marvellous female?

Our Independent Delhi escorts gives the finest camaraderie, rub administrations and mastery sessions by the most excellent young ladies. We convey your picked buddy straight to your doorstep. It doesn’t make a difference whether you are living here, working in the range or simply going by; the length of you are a conscious man of his word, our women will be charmed to come and experience you at your home or lodging room.Our friends are accessible for outcalls to legitimate high class lodgings or flats just, and are giving services to everybody. If its not too much trouble visit our pages and book your own free darling online or get in touch with us whenever amid the week for same day services.

Escort Delhi Hotel Models

At the point when ringing, you ought to compassionate require ahead. That way you will furnish us with enough time to get prepared and actuate you with amazement. There are special offers and costs when you make an errand for more hours. Achieving one or a more noteworthy measure of our energetic ladies is basic: basically recall, be a respectable man and act legitimately. When you'll meet the escort, present yourself agreeably, our young women are persons too. An OK discourse is the best way to deal with having a brilliant time with these stunning ladies from Delhi Hotel Escort.They dress and act to fulfill you and go to your every social need. On the off chance that by fortune, you will request to know her better, then you can banter with us and ourselves can spare her for a few hours. You can contact her reliably on the off chance that she's open. You can likewise contribute a lot more, to the degree of purchasing her blossoms and being with her consistently. Every adolescent individual that we submit has unfathomable social qualities and won't treat their companions with absence of hobby. The escorts understand that you are captivating and should make sense of your every wish or aching. Consider what you require, or whom you require from our decision, and our mate organization will have what is best for you. We offer our help 24 hours a day and we are holding up to meet in Delhi. Our association can systematize a social event in a matter of minutes at your home, or inn room.

Escorting Companions

We are discrete and specialists with regards to your own data. Any information you give won't be conferred to any of our outsider partner. We get the best escort that knows this and will act as needs be, by not sharing anything. You don't case to feel anxious around them; their behaviour won't make you feel in any way uncomfortable. Both of you will have a marvellous interim together.Our offices mean to supply you with the capacity you encourage for and will endeavour to help as much as sensibly conceivable. Your success and delight is the thing that matters and thou will be furnished with the perfect escort. The cash you pay for your joy is nothing contrasted and the amount of fun you will have. Try not to be flabbergasted if the next day in Delhi, you should go again on this incredible ride. All of information about these young women is here, on this site, and if you have to make sense of extra viewpoints, you can just get in touch with us.

Models and escorts from Delhi

Our broads rush to ruin you to satisfaction. You can skim stunning models or the conventional kind of lady. On the off chance that some way or another you don't see the woman you had constantly needed, and after that call us at any rate, as we have various holy messengers available, whose photos are not on the display? When you call, our pleasant receptionists will comfort you and aide you through our straightforward booking technique to pick your optimal High Class Escorts in Delhi
 
ลิงค์ที่เกี่ยวข้อง : https://www.vdelhiescorts.com
Sonam Sinha [132.154.112.xxx] เมื่อ 15/05/2022 18:05
1667
อ้างอิง

mina
 
mina [45.119.45.xxx] เมื่อ 16/05/2022 13:43
1668
อ้างอิง

mina
 
mina [45.119.45.xxx] เมื่อ 16/05/2022 13:44
1669
อ้างอิง

mina
My Hero Academia Hentai My Hero Academia Porn My Hero Academia Porn My Hero Academia Hentai Uncensored Hentai Hentai Videos Hentai Video Lesbian Hentai Yuri Hentai Manytoon Manytoons Many toon Games Porn Game Porn Gamesporn Gameporn Myhentailist Myhentailist My hentai list My hentai list Kissjav Kiss Jav Jav Cosplay Porn Cosplayporn Porngram Porn Gram Horny Freak HornyFreak Horny Freak HornyFreak 8muses rule34 rule 34 rule 34 paheal rule34paheal danbooru gelbooru hypnohub xbooru giantessbooru sankakucomplex 8muses hornyfreak horny freak hornyfreak horny freak porngram porn gram cosplayporn cosplay porn porn kissjav kiss jav jav lesbianhentai lesbian hentai lesbian 3dporn 3d porn 3dhentai 3d hentai manytoon many toon gamesporn games porn porngames porn games myhentailist myhentai list hentailist my hentai list myhentailist myhentai list hentailist my hentai list 8muses 8muses comics Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai 8muses milftoon 8muses jab 8muses hentai 8muses porn 8muses xxx 8muses porn comic 8muses tg milftoon 8muses 8muses recent 8muses savita comics 8 muses 8muses download porn comics 8muses jab comix 8muses jab 8muses 8 muse porn 8muses new 8muses sex comics 8muses sex porn comics 8 muses tg comic 8muses 8 muse porn comics 8muses comic porn porn 8muses sites like 8muses 8muses cartoon sex comics 8muses 8muses tg comic 8muses latest 8muses free sex comics 8 muses comic porn 8muses 8 muse comic porn free 8muses comix 8muses 8muses adult comics 8muses manga 8musesxxx 8muses free sex comics 8muses galleries 8muses cartoon porn websites like 8muses 8mouses comics 8muses toon zzz comic 8 muses 8muses search 8muses xxx comics adult comics 8 muses 8muses recently added 8muses website cartoon 8muses 8muses sex and porn comics recently updated 8muses 8muses anime cartoon porn 8muses 8muses sex and porn 8muses free comics muse8 cartoon xxx comics 8muse site like 8muses 8muses new comics 8 muse xxx comics 8muses comic xxx 8muses rule 34 8muses r34 8muses hentai manga 8muses hentai comic hentai 8muses 8muses recently updated 8muse sex sexpedition 8muses xxx comics 8muses xxx 8muse 8muses 8muses comics 8muses milftoon 8muses jab 8muses hentai 8muses porn 8muses xxx 8muses porn comic 8muses tg milftoon 8muses 8muses recent 8muses savita comics 8 muses 8muses download porn comics 8muses jab comix 8muses jab 8muses 8 muse porn 8muses new 8muses sex comics 8muses sex porn comics 8 muses tg comic 8muses 8 muse porn comics 8muses comic porn porn 8muses sites like 8muses 8muses cartoon sex comics 8muses 8muses tg comic 8muses latest 8muses free sex comics 8 muses comic porn 8muses 8 muse comic porn free 8muses comix 8muses 8muses adult comics 8muses manga 8musesxxx 8muses free sex comics 8muses galleries 8muses cartoon porn websites like 8muses 8mouses comics 8muses toon zzz comic 8 muses 8muses search 8muses xxx comics adult comics 8 muses 8muses recently added 8muses website cartoon 8muses 8muses sex and porn comics recently updated 8muses 8muses anime cartoon porn 8muses 8muses sex and porn 8muses free comics muse8 cartoon xxx comics 8muse site like 8muses 8muses new comics 8 muse xxx comics 8muses comic xxx 8muses rule 34 8muses r34 8muses hentai manga 8muses hentai comic hentai 8muses 8muses recently updated 8muse sex sexpedition 8muses xxx comics 8muses xxx 8muse rule34 rule 34 r34 rule34 porn rule34 xxx rule 34 paheal r34 rule34xxx rule 34 website rule 34 hentai rule34 hentai rule34 sex r34 hentai r34 porn r34 xxx rule 34 site rule 34 reddit rule 34 x hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai anime hentai hentai hentai hentai hentai hentai hentai hentai hentai hentai Hentai/a>. Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Hentai Games Hentai Hentai Hentai Hentai Porn Porn Horny Horny Porn Porn rule34 8muses hornyfreak horny freak hornyfreak horny freak porngram porn gram cosplayporn cosplay porn porn kissjav kiss jav jav lesbianhentai lesbian hentai lesbian 3dporn 3d porn 3dhentai 3d hentai manytoon many toon gamesporn games porn Hentai Manga Hentai Comics Hentai TV Anime Sex Hentai Porn
 
mina [45.119.45.xxx] เมื่อ 16/05/2022 13:45
1670
อ้างอิง

Tawk Girls
Greater Noida Escort Service
Service in Best City
Escorts Service Muzaffarnagar  | Escorts Service Deoghar  | Escorts Service Nalgonda  | Escorts Service Gir Somnath  | Escorts Service Chitradurga  | Escorts Service Khordha  | Escorts Service Kachiguda  | Escorts Service Sahaswan  | Escorts Service Nawada  | Escorts Service Belapur  | Escorts Service Ghatkopar  | Escorts Service Aligarh  | Escorts Service Basti  | Escorts Service Mehsana  | Escorts Service Manglaur  | Escorts Service Thaltej Chokdi  | Escorts Service Kottayam  | Escorts Service Kharagpur  | Escorts Service Narnaul  | Escorts Service Gulbarga  | Escorts Service Bellary  | Escorts Service Baddi  | Escorts Service Anna Nagar  | Escorts Service Dharuhera  | Escorts Service Dholpur  | Escorts Service Kumbakonam  | Escorts Service Aizawl  | Escorts Service Nagrota Bagwan  | Escorts Service Ganjam  | Escorts Service Ratlam | Escorts Service Lakhimpur | Escorts Service Hanumangarh | Escorts Service Shantipur | Escorts Service Dhulian | Escorts Service Malappuram | Escorts Service Saharsa | Escorts Service Nalanda | Escorts Service Jogeshwari | Escorts Service Rajahmundry | Escorts Service Muktsar | Escorts Service Sehore | Escorts Service Alwar | Escorts Service Rewari | Escorts Service Ayodhya | Escorts Service Kapurthala | Escorts Service Anantapuram | Escorts Service Besant Nagar | Escorts Service Kasganj | Escorts Service Tenali | Escorts Service Berhampur | Escorts Service Bagalkot | Escorts Service Silchar | Escorts Service Chandausi | Escorts Service Madurai | Escorts Service Sagar | Escorts Service Lakdikapool | Escorts Service Karauli | Escorts Service Charkhi Dadri | Escorts Service Naigaon | Escorts Service Ramanathapuram | Escorts Service Guna | Escorts Service Tehri | Escorts Service Sion | Escorts Service Kozhikode | Escorts Service Bhimavaram | Escorts Service Dharmavaram | Escorts Service Jawalamukhi | Escorts Service Nerul | Escorts Service Narendra Nagar | Escorts Service Harrington Road | Escorts Service Darjeeling | Escorts Service Mahanagar | Escorts Service Palakollu | Escorts Service Murwara
 
ลิงค์ที่เกี่ยวข้อง : https://www.tawkgirls.in/greater-noida-escort-service.html
Tawk Girls [106.223.36.xxx] เมื่อ 16/05/2022 14:10
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708709710711712713714715716717718719720721722723724725726727728729730731732733734735736737738739740741742743744745746747748749750751752753754755756757758759760761762763764765766767768769770771772773774775776777778779780781782783784785786787788789790791792793794795796797798799800801802803804805806807808809810811812813814815816817818819820821822823824825826827828829830831832833834835836837838
ความคิดเห็นของผู้เข้าชม
ชื่อผู้แสดงความคิดเห็น :
สถานะ : รหัสผ่าน :
ลิงค์ที่เกี่ยวข้อง :
รหัสความปลอดภัย :