Selasa, 25 September 2018
Selasa, 03 Juli 2018
HOLE OF FIRE BOOK
PESAN SEGERA!
EDISI PREMIUM
Judul : Hole of Fire
Tebal : 129 hlm
Massa : 0 gram
Bentuk : pdf
Seberapa yakin Anda percaya bahwa gaya gravitasi berasal dari sebuah benda maha dahsyat di inti Bumi ?
Seberapa yakin Anda percaya tentang black hole ?
Buktikan di buku ini!
"Berawal dari sebuah ilham yang sangat mendalam dipadukan dengan fakta eksperimen ilmiah dalam mengupas misteri sebuah gaya gravitasi Buku ini akan membawa Anda mengenal hakikat gaya tarik gravitasi yang sebenarnya".
*WARNING*
Buku ini akan membuat Anda lebih pintar dari Einstein
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Kamis, 14 Juli 2011
phonon
Phonon Engineering: From Concepts to Device Applications
Phonons are quantized modes of vibration occurring in a rigid crystal lattice, such as the atomic lattice of a solid. Phonons manifest themselves in all properties of materials: phonons limit electrical conductivity, optical phonons strongly influence optical response, while acoustic phonons carry heat in insulators and semiconductors. Long-wavelength phonons gives rise to sound in solids (hence the name phonon). Spatial confinement of phonons in nanostructures can strongly affect the phonon spectrum and modify phonon properties such as phonon group velocity, polarization, density of states and electron - phonon interaction. Thus, nanostructures offer a new way of controlling phonon transport and electron - phonon interaction via tuning phonon dispersion relation, i.e. phonon engineering. The idea of engineering phonon dispersion in nanostructures has the potential to be as powerful as the idea of the band-gap engineering for electrons, which is now utilized in a variety of devices (see Figure 1). For an overview of the development of the phonon engineering concept, see the extracts from the invited plenary talk given by Professor Balandin at the International Conference on Phonon Scattering 2004, St. Petersburg, Russia and at the California Nanosystems Institute, University of California, Los Angeles.
Figure 1. Illustration of the phonon engineering concept in hetero- and nanostructures.
After A.A. Balandin, Plenary Talk, PHONONS 2004 International Conference.
Professor Balandin's Nano-Device Laboratory (NDL) research group offers a unique blend of both theoretical and experimental research in phonon engineering. The problems of acoustic phonon transport are closely related to heat removal and thermal management of elecetronic devices and circuits. As the feature size of the devices continues to decrease and the amount of dissipated power continues to increase the problem of thermal management becomes extremely important for further development of electronic industry. The heat removal issue is becoming more complicated due to a number of additional factors such as (i) introduction of new materials (alternative dielectrics, SOI, etc.), which have low thermal conductivity; (ii) increase in the number of interconnects and layers of different materials in chip designs with corresponding increase in the total thermal boundary resistance; (iii) higher switching speeds; (iv) increased device integration (vertical MOSFETs, proposed 3D integration, etc.); and size effects that lead to decrease in the thermal conductivity of the material itself (phonon – boundary scattering, etc.). NDL researchers carry out experimental investigation of thermal transport in nanostructured and layered semiconductor materials (see Figure 2).
Figure 2. Measured thermal conductivity in quantum dot superlattices, NDL 2004.
In recent years, Professor Balandin and researchers of the Nano-Device Laboratory (NDL) worked on generalization of the concept of phonon engineering with the goal to achieve the “customer-tailored” phonon spectrum for the enhancement of operation of the electronic, thermoelectric and optoelectronic devices. In a recently published Applied Physics Letter it was shown that phonon spectrum in acoustically mismatched nanostructures can be engineered in such a way that the phonon group velocity increases along a chosen direction (see Figure 3), thus imporving the heat removal. In several other papers (see the Publication List) NDL researchers proposed a method of phonon depletion in certain regions of the device and formulated conditions for achieving phonon band gaps in semiconductor quantum dot superlattices. Some thrusts of the phonon engineering research in NDL are partially supported by the National Science Foundation and the DARPA-SRC funded MARCO Center on Functional Engineered Nano Artichectonics (FENA) .
Figure 3. Phonon group velocity increase due to the "acoustically hard" boundaries.
Researchers of the Nano-Device Laboratory (NDL) carry out experimental nanophononic research frequently crossing traditional boarder lines among the disciplines: from semiconductor nanostructures to carbon nanotubes and viruses. Raman and Brillouin spectroscopies are used to investigate confined optical and acoustic phonons in quantum dots and other nanostructures. More information about Raman spectroscopy in NDL can be found HERE. A home built 3w-thermal conductivity measurement setup combined with cryogenic equipment allows NDL researchers to study phonon transport in nanostructural materials over the wide temperature range experimentally. Cylindrically shaped viruses, such as TMV, have been used as templates for self-assembly of nanostructures and elements of nanoelectronic circuits. NDL researchers study phonons in functionalized TMV and TMV-based hybrid nanostructures both experimentally (see Figure 4) and theoretically. More about calculation of phonon modes in viruses and bio-nanotechnology research conducted in NDL can be found HERE.
Figure 4. Raman spectra of TMV virus under visible laser excitation. NDL, 2004.
Another thrust of the nanophononics research in the Nano-Device Laboratory (NDL) is theoretical and experimental investigation of optical phonons in wurtzite ZnO and GaN quantum dots (see Figure 5). Dr. Fonoberov and Professor Balandin derived an exact integral equation, which defines interface and confined polar optical-phonon modes in wurtzite nanocrystals. It has been shown theoretically, that while the frequency of confined polar optical phonons in zincblende nanocrystals is equal to that of the bulk crystal phonons, the confined polar optical phonons in wurtzite nanocrystals have a discrete spectrum of frequencies different from those of the bulk crystal. Details of this investigation have been reported in a series of papers published in Physical Review B and Journal of Applied Physics (see the Publication List)
Figure 5. Calculated optical phonon modes in wurtzire semiconductor quantum dots.
Results are after V.A. Fonoberov and A.A. Balandin, Phys. Rev. B (2004).
GaN and GaN-based III-V alloys are promising materials for the next generation of high-power electronic, microwave and optoelectronic devices. For all envisioned applications of GaN materials it is important to effectively remove the generated heat. Thus, the thermal conductivity of GaN and AlGaN alloys, used in GaN/AlGaN heterostructure field-effect transistors (HFETs) is a very important characteristic. NDL is the first group to carry out systematic experimental and theoretical study of thermal conduction in AlGaN films (see Figure 6).
Figure 6. Thermal conductivity in AlGaN alloy as a function of Al mole fraction.
Results are after W.L. Liu and A.A. Balandin, J. Appl. Phys., 2005.
More information on the PHONON ENGINEERING and other projects currently under way in the Nano-Device Laboratory (NDL) can be found HERE. To join NDL as a graduate student or postdoctoral research visit the web-page HERE. To learn more about course offering in the field of Materials, Devices and Circuits visit the web-page HERE.
| NDL Contact Info | Prof. A.A. Balandin | NDL Personnel |
NDL Home • EE • UCR
Phonons are quantized modes of vibration occurring in a rigid crystal lattice, such as the atomic lattice of a solid. Phonons manifest themselves in all properties of materials: phonons limit electrical conductivity, optical phonons strongly influence optical response, while acoustic phonons carry heat in insulators and semiconductors. Long-wavelength phonons gives rise to sound in solids (hence the name phonon). Spatial confinement of phonons in nanostructures can strongly affect the phonon spectrum and modify phonon properties such as phonon group velocity, polarization, density of states and electron - phonon interaction. Thus, nanostructures offer a new way of controlling phonon transport and electron - phonon interaction via tuning phonon dispersion relation, i.e. phonon engineering. The idea of engineering phonon dispersion in nanostructures has the potential to be as powerful as the idea of the band-gap engineering for electrons, which is now utilized in a variety of devices (see Figure 1). For an overview of the development of the phonon engineering concept, see the extracts from the invited plenary talk given by Professor Balandin at the International Conference on Phonon Scattering 2004, St. Petersburg, Russia and at the California Nanosystems Institute, University of California, Los Angeles.
Figure 1. Illustration of the phonon engineering concept in hetero- and nanostructures.
After A.A. Balandin, Plenary Talk, PHONONS 2004 International Conference.
Professor Balandin's Nano-Device Laboratory (NDL) research group offers a unique blend of both theoretical and experimental research in phonon engineering. The problems of acoustic phonon transport are closely related to heat removal and thermal management of elecetronic devices and circuits. As the feature size of the devices continues to decrease and the amount of dissipated power continues to increase the problem of thermal management becomes extremely important for further development of electronic industry. The heat removal issue is becoming more complicated due to a number of additional factors such as (i) introduction of new materials (alternative dielectrics, SOI, etc.), which have low thermal conductivity; (ii) increase in the number of interconnects and layers of different materials in chip designs with corresponding increase in the total thermal boundary resistance; (iii) higher switching speeds; (iv) increased device integration (vertical MOSFETs, proposed 3D integration, etc.); and size effects that lead to decrease in the thermal conductivity of the material itself (phonon – boundary scattering, etc.). NDL researchers carry out experimental investigation of thermal transport in nanostructured and layered semiconductor materials (see Figure 2).
Figure 2. Measured thermal conductivity in quantum dot superlattices, NDL 2004.
In recent years, Professor Balandin and researchers of the Nano-Device Laboratory (NDL) worked on generalization of the concept of phonon engineering with the goal to achieve the “customer-tailored” phonon spectrum for the enhancement of operation of the electronic, thermoelectric and optoelectronic devices. In a recently published Applied Physics Letter it was shown that phonon spectrum in acoustically mismatched nanostructures can be engineered in such a way that the phonon group velocity increases along a chosen direction (see Figure 3), thus imporving the heat removal. In several other papers (see the Publication List) NDL researchers proposed a method of phonon depletion in certain regions of the device and formulated conditions for achieving phonon band gaps in semiconductor quantum dot superlattices. Some thrusts of the phonon engineering research in NDL are partially supported by the National Science Foundation and the DARPA-SRC funded MARCO Center on Functional Engineered Nano Artichectonics (FENA) .
Figure 3. Phonon group velocity increase due to the "acoustically hard" boundaries.
Researchers of the Nano-Device Laboratory (NDL) carry out experimental nanophononic research frequently crossing traditional boarder lines among the disciplines: from semiconductor nanostructures to carbon nanotubes and viruses. Raman and Brillouin spectroscopies are used to investigate confined optical and acoustic phonons in quantum dots and other nanostructures. More information about Raman spectroscopy in NDL can be found HERE. A home built 3w-thermal conductivity measurement setup combined with cryogenic equipment allows NDL researchers to study phonon transport in nanostructural materials over the wide temperature range experimentally. Cylindrically shaped viruses, such as TMV, have been used as templates for self-assembly of nanostructures and elements of nanoelectronic circuits. NDL researchers study phonons in functionalized TMV and TMV-based hybrid nanostructures both experimentally (see Figure 4) and theoretically. More about calculation of phonon modes in viruses and bio-nanotechnology research conducted in NDL can be found HERE.
Figure 4. Raman spectra of TMV virus under visible laser excitation. NDL, 2004.
Another thrust of the nanophononics research in the Nano-Device Laboratory (NDL) is theoretical and experimental investigation of optical phonons in wurtzite ZnO and GaN quantum dots (see Figure 5). Dr. Fonoberov and Professor Balandin derived an exact integral equation, which defines interface and confined polar optical-phonon modes in wurtzite nanocrystals. It has been shown theoretically, that while the frequency of confined polar optical phonons in zincblende nanocrystals is equal to that of the bulk crystal phonons, the confined polar optical phonons in wurtzite nanocrystals have a discrete spectrum of frequencies different from those of the bulk crystal. Details of this investigation have been reported in a series of papers published in Physical Review B and Journal of Applied Physics (see the Publication List)
Figure 5. Calculated optical phonon modes in wurtzire semiconductor quantum dots.
Results are after V.A. Fonoberov and A.A. Balandin, Phys. Rev. B (2004).
GaN and GaN-based III-V alloys are promising materials for the next generation of high-power electronic, microwave and optoelectronic devices. For all envisioned applications of GaN materials it is important to effectively remove the generated heat. Thus, the thermal conductivity of GaN and AlGaN alloys, used in GaN/AlGaN heterostructure field-effect transistors (HFETs) is a very important characteristic. NDL is the first group to carry out systematic experimental and theoretical study of thermal conduction in AlGaN films (see Figure 6).
Figure 6. Thermal conductivity in AlGaN alloy as a function of Al mole fraction.
Results are after W.L. Liu and A.A. Balandin, J. Appl. Phys., 2005.
More information on the PHONON ENGINEERING and other projects currently under way in the Nano-Device Laboratory (NDL) can be found HERE. To join NDL as a graduate student or postdoctoral research visit the web-page HERE. To learn more about course offering in the field of Materials, Devices and Circuits visit the web-page HERE.
| NDL Contact Info | Prof. A.A. Balandin | NDL Personnel |
NDL Home • EE • UCR
Senin, 28 Maret 2011
Kamis, 30 Desember 2010
add(Timin dalam DNA, Urasil dalam RNA, mengapa?)
December 27, 2010
assalamu’alaikum warohmatulloh,
ana ada dikit masukan.
mengapa timin dalam DNA dan urasil dalam RNA :
1.karena timin secara sunnatulloh berikatan dengan deoksiribosa(dengan tambahan oksigen tentunya),sementara urasil dengan ribosa,sebab jika urasil berpasangan dengan deoksiribosa maka sistem struktur RNA akan berantakan,lihat Hairpin loop dalam kaidah RNA.
2.Enzim tertentu cocok dengan ‘sistem’ kerja DNA begitupun halnya pada RNA sebagai penyampai pesan genetik punya ‘sistem’ enzim tertentu sesuai strukturnya dan komposisinya.
3.DNA dan RNA masing masing dapat diserang virus dan tak dipengaruhi faktor gugus,baik gugus CH3-,H-,PO4-,dll.
wallohu’alam
Jumat, 10 September 2010
Bismillah
EFEK ELEKTRON SEJAJAR YANG MENYEBABKAN SUHU DALAM TIAP-TIAP BAGIAN API BERBEDA -BEDA.
hal ini terjadi karena adanya proses sebagai berikut:
1.Karena adanya efek gaya yang diakibatkan posisi elektron-elektron yang sejajar sehingga terjadi gaya tambahan yang jika kecepatan pergerakan elektron elektron ini lebih cepat maka justru yang dihasilkan adalah energi panas sistem api yang lebih rendah
2.Karena pergerakan kumpulan elektron dalam sistem ini lebih cepat maka tekanan sistem lebih rendah maka positron akan lebih banyak tertarik ke arah sistem ini akibatnya suhu sistem akan lebih rendah
wallohu'alam
Kamis, 12 Agustus 2010
math in islam
KOREKSI TERHADAP TEORI BIDANG KARTESIAN
BISMILLAH
Dalam bidang kartesian,misal x^2+y^2=1 dinyatakan dengan suatu lingkaran dengan pusat (0,0) dan jari-jari=1.
Apakah hal ini cukup benar?
Mari kita analisis hal ini dalam bidang matematika diskrit dalam bagian ilmu relasi.
ternyata setelah kita analisis,hal ini kuranglah tepat,karena relasi untuk anggota x^2+y^2=1 tidak hanya (1,0),(0,1),(-1,0) dan (0,-1),tetapi terdapat 'anggota' lain yang sangat banyak bahkan tak hingga(silahkan buktikan dengan syarat nilai x^2 ditambah y^2 sama dengan 1) salah satunya
(1/2,1/2akar 3)...
Dengan demikian maka akan dihasilkan segi tak hingga yang memiliki sudut tak hingga juga.Hal ini jelas berbeda dengan lingkaran yang sudutnya hanya 360 derajat ditinjau dari sumbu x dan y.
Jadi dalam pernyataan kertesian x^2+y^2=1 dengan pencitraan lingkaran dengan pusat (0,0) dan r=1 adalah dhoif(lemah)hujjahnya(buktinya).
wallohu'alam
BISMILLAH
Dalam bidang kartesian,misal x^2+y^2=1 dinyatakan dengan suatu lingkaran dengan pusat (0,0) dan jari-jari=1.
Apakah hal ini cukup benar?
Mari kita analisis hal ini dalam bidang matematika diskrit dalam bagian ilmu relasi.
ternyata setelah kita analisis,hal ini kuranglah tepat,karena relasi untuk anggota x^2+y^2=1 tidak hanya (1,0),(0,1),(-1,0) dan (0,-1),tetapi terdapat 'anggota' lain yang sangat banyak bahkan tak hingga(silahkan buktikan dengan syarat nilai x^2 ditambah y^2 sama dengan 1) salah satunya
(1/2,1/2akar 3)...
Dengan demikian maka akan dihasilkan segi tak hingga yang memiliki sudut tak hingga juga.Hal ini jelas berbeda dengan lingkaran yang sudutnya hanya 360 derajat ditinjau dari sumbu x dan y.
Jadi dalam pernyataan kertesian x^2+y^2=1 dengan pencitraan lingkaran dengan pusat (0,0) dan r=1 adalah dhoif(lemah)hujjahnya(buktinya).
wallohu'alam
Rabu, 04 Maret 2009
sound in your life
The Tympanic Membrane
The tympanic membrane or "eardrum" receives vibrations traveling up the auditory canal and transfers them through the tiny ossicles to the oval window, the port into the inner ear.
The eardrum is some fifteen times larger than the oval window of the inner ear, giving an amplification of about fifteen compared to a case where the sound pressure interacted with the oval window alone.
The tympanic membrane is very thin, about 0.1 mm, but it is resilient and strong.(Zemlin)
Active graphic
You may reach information about the nearby structures of the ear by clicking on the item of interest on the illustration.
Frequencies for maximum sensitivity of human hearing
The hearing curves show a significant dip in the range 2000-5000 Hz with a peak sensitivity around 3500 -4000 Hz. This is associated with the resonance of the auditory canal. There is another enhanced sensitivity region at about 13,500 Hz which may be associated with the third harmonic resonance of the auditory canal. The high sensitivity region at 2-5kHz is very important for the understanding of speech.
Ossicle Vibration
The vibration of the eardrum is transmitted to the oval window of the inner ear by means of the ossicles, which achieve an amplification by lever action. The lever is adjustable under muscle action and may actually attenuate loud sounds for protection of the ear.
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