الملف الأصلي (3٬060 × 2٬036 بكسل حجم الملف: 1٫05 ميجابايت، نوع MIME: image/jpeg)

ملخص

الوصف
English: Original caption: "This technology is known as a Tunable Diode Laser (TDL) gas sensor. The heart of the TDL system is a small laser diode (about 2mm square) that produces a narrow and specific wavelength of light tuned to a harmonic frequency of the water vapor molecule in the near infrared band. The light causes the molecule to vibrate and absorb the energy.

Once adjusted to the specific frequency of the molecule, the laser is minutely tuned to different wavelengths on either side of the target wavelength. By comparing the light energy being absorbed at the water vapor frequency, to the light energy at the surrounding frequencies, a very precise measurement can be made. Multiple measurements are made every second, making the system quick to respond to variations in the target gas.

TDL gas sensing technology is particularly good at detecting low levels of gases at the parts per million or even parts per billion level. With the vast majority of manufactured products relying more and more on gas measurement of some kind, commercial applications for this technique are broad. In every environment from wafer fabrication process control in the semiconductor industry to detecting trace levels of noxious gases in stack emissions, TDLs will be making news in the industrial and environmental monitoring sectors of the economy for years to come."
التاريخ (Date from the IPTC metadata of the original TIFF version)
المصدر Jet Propulsion Laboratory website: http://technology.jpl.nasa.gov/gallery/index.cfm?page=imageDetail&ItemID=120&catId=8 (archive)
المؤلف
This image has currency in it to indicate scale.

Using coins for scale is discouraged as it will require people unfamiliar with them to look up the dimensions or guess, both of which defeat the purpose of the object in the first place. Coins can also reinforce a geographical bias, and some coins' designs are copyrighted.

Ideally, a photograph should include a ruler with the subject (example) or an added scale marking. SI ("metric") units are the most commonly used worldwide (see meter and centimeter).

Images with coins to indicate scale

Common coin diameters for reference:

  • U.S. dollar (as of?):
    • 1¢: 19.05 mm, 0.75 in
    • 5¢: 21.21 mm, 0.84 in
    • 10¢: 17.91 mm, 0.71 in
    • 25¢: 24.26 mm, 0.94 in
    • 50¢: 30.61 mm, 1.22 in
    • $1: 26.5 mm, 1.02 in
  • Canadian dollar (as of?):
    • 1¢: 19.05 mm, 0.75 in
    • 5¢: 21.2 mm, 0.83 in
    • 10¢: 18.03 mm, 0.71 in
    • 25¢: 23.88 mm, 0.94 in
    • 50¢: 27.13 mm, 1.07 in
    • $1: 26.5 mm, 1.02 in
    • $2: 28 mm, 1.1 in
  • Pound sterling as of 2021:
    • 1p: 20.32 mm, 0.8 in
    • 2p: 25.91 mm, 1.02 in
    • 5p: 18 mm, 0.71 in
    • 10p: 24.5 mm, 0.96 in
    • 20p: 21.4 mm, 0.84 in
    • 50p: 27.3 mm, 1.07 in
    • £1: 23.03–23.43 mm, 0.91–0.92 in
    • £2: 28.4 mm, 1.12 in
  • Euro as of 2002:
    • 1c: 16.25 mm, 0.64 in
    • 2c: 18.75 mm, 0.74 in
    • 5c: 21.25 mm, 0.84 in
    • 10c: 19.75 mm, 0.78 in
    • 20c: 22.25 mm, 0.88 in
    • 50c: 24.25 mm, 0.95 in
    • €1: 23.25 mm, 0.92 in
    • €2: 25.75 mm, 1.01 in

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ترخيص

Public domain يقع هذا العمل في النِّطاق العامّ في الولايات المُتحدة الأمريكيَّة لأَنَّه عملٌ خالِصٌ من إِنتاج وكالة الفضاء الأمريكيَّة. تنصُ حقوق التَّأليف والنَّشر الخاصَّة بوكالة الفضاء الأمريكيَّة على أنَّ "أعمال الوكالة غير مَحميَّة بحقوق التَّأليف والنَّشر ما لم يُذكر خلافُ ذلك". لمزيدٍ من المعلومات انظر القالِب {{PD-USGov}} وصفحة حقوق التَّأليف والنَّشر الخاصَّة بالوكالة وصفحة سياسة الصُّور الخاصَّة بمُختبر الدَّفع النَّفَّاث.
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  • 2005-08-27 16:09 Deglr6328 3060×2036×8 (1096300 bytes) original caption: "This technology is known as a Tunable Diode Laser (TDL) gas sensor. The heart of the TDL system is a small laser diode (about 2mm square) that produces a narrow and specific wavelength of light tuned to a harmonic frequency of the water

الشروحات

أضف شرحاً من سطر واحد لما يُمثِّله هذا الملف
Laser diode

العناصر المصورة في هذا الملف

يُصوِّر

٤ نوفمبر 1999

تاريخ الملف

اضغط على زمن/تاريخ لرؤية الملف كما بدا في هذا الزمن.

زمن/تاريخصورة مصغرةالأبعادمستخدمتعليق
حالي02:47، 7 يوليو 2007تصغير للنسخة بتاريخ 02:47، 7 يوليو 20073٬060 × 2٬036 (1٫05 ميجابايت)Seedermaster~commonswiki{{Information |Description=original caption: "This technology is known as a Tunable Diode Laser (TDL) gas sensor. The heart of the TDL system is a small laser diode (about 2mm square) that produces a narrow and specific wavelength of light tuned to a harm

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