Re: Help, help help!!! (fwd)

[giang@essc.psu.edu (Nong Tuan Giang)]

>Cuong xin chan thanh cam on Anh Ca, Anh VuNguyenTha`nh, Anh TLthanh, 
>ba.n So+? va- Anh Toa-n (toan@usa.net) da giu'p cho Cuong nhung tin tuc 
>co gia tri de Cuong chuan bi cho cai Presentation sap toi. Tuy vay Cuong 
>van con co' mot so^' thac mac muon hoi them, phien cac Anh giu'p no^'t.
>
>1. Anh Tha`nh co' no'i la- khi' gi- do' trong tu? la.nh thi do' la- khi' 
>Freon. Nhung hi-nh nhu la co' hai loai freon thi- pha?i vi khi o VN ca'i 
>tu? la.nh nha Cuong no' bi. do- gas va phai di nap lai. Khi den cua hang 
>thi- nguoi ta hoi la thich loai gas na-o, freon 11 va freon 22 moi loai 
>moi tie^-n. Vay thi- chu'ng kha'c nhau die^?m gi- va- loai na-o la-m 
>thu?ng Ozone layer??? Co-n voi tu? la.nh thi cha'c la loai nao da(t hon 
>thi tot hon :-))
Chat gay phan huy Ozone co ten chung la CFC, hai loai Freon Cuong neu tren
du gay phan huy Ozone

>2. Do+n vi. do a'nh sa'ng thuong la- Lux, va^.y thi co-n co' don vi. nao 
>kha'c kho^ng??? Do+n vi. do UV co' pha?i la- Lux kho^ng??? Ca'c den UV 
>thuong co' kha? nang pha't ra bao nhieu don vi.???
Co rat nhieu don vi do radiation (anh sang la mot dang cua radiation), khong
the ke het duoc o day, vi du nhu: phot, stilb, nit, troland, nox, goblin,
gremlin; those are photometric units, to name only a few
>3. Trong Lab cua Cuong du-ng ra^'t nhieu UV lamp de^? khu+? tru-ng. Ve 
>nguye^n ly' cua de-n thi- Cuong da hie^?u nho+- ba-i cua Anh Thanh va- 
>cua So+?. Va^.y xin ho?i the^m the^' na-y: trong cataloge cu?a de-n ghi 
>so^' gio+- su+? du.ng, thu+o+-ng khoa?ng 2000gio+-. Va^.y khi qua' so^' 
>gio+- do' thi- no' kho^ng pha't ra UV nua hay sao??? ta.i sao va^.y???
Moi vat lon hon 0 do Kelvin deu phat ra radiation o moi buoc song, tuy nhien
lamda max lien quan den nhiet do cua vat theo cong thuc sau
Lamda x T=3000
lamda: buoc song cuc dai(micron), T nhiet do cua vat (K)
Thi du: Mat troi nong 6000K, nen phat ra lamda max la 0.5 micron hay 500 nanomet
sau 2000 gio neu den con sang thi con phat ra UV, neu den khong hoat dong
thi khong co UV nua, 2000 day la tuoi tho lam viec cua den (cua giay toc den)
>4. UV (trong tu nhien) duoc tao ra tu mat troi nhung no khong den duoc 
>trai dat la do bi Ozone layer hap thu. Vay thi- neu Ozone layer khong 
>thung thi tai be mat trai dat co' UV hay khong? neu co' thi chiem bao 
>nhieu % trong solar radiation reached to earth surface? Khi do thi ca^y 
>co^'i ba(-ng ca'ch nao cho^'ng la.i duoc UV vi chlorophille trong la' 
>cay la- mot pigment ra^'t de bi. pha^n hu?y.
Theo cong thuc tren muon co UV thi can nhiet do cao, neu UV mat troi da bi
trai dat chan thi tren mat dat khong co UV nua

>5. UV co' kha? nang dam xuye^n the na-o? No' co' xuye^ng qua nuoc nhu la 
>visible radiation kho^ng??? No' co' the^? xuye^n qua ki'nh ma-u 
>kho^ng??? Cuong thay trong qua?ng ca'o mo^.t ki'nh deo ma('t la- ngan 
>duoc UV B, vay thi- ki'nh loai nao ngan duoc ca? ba loai UV??? 
Day la comercial ad thoi, dung tin lam gi
>6. Cung trong qua?ng ca'o cua mot so^' loa.i skill creams thay ghi la- 
>cho^'ng duoc UV, vay thi- ca'i cha^'t gi- trong do' la- quye^'t di.nh 
>ti'nh cha^'t na-y???
>
>Va-i cau ho?i nho?, ra^'t mong cac Anh cac Chi bo+'t chu't tho+-i gian 
>giu'p Cuong vo+'i.
>
>Xin chan thanh cam on.
>
>Phu Cuong in Ghent
>
>
>