24-26 Kasım 2011 - 19.Ulusal Sıvı Hal Sempozyumu

24-26 Kasım 2011 - 19.Ulusal Sıvı Hal Sempozyumu

SEMPOZYUM BİLİM KURULU
Prof. Dr. Zehra AKDENİZ
Piri Reis Üniversitesi
Prof. Dr. Sevim AKYÜZ
Kültür Üniversitesi
Prof. Dr. A. Nihat BERKER
Sabancı Üniversitesi
Prof. Dr. Bedia ERİM BERKER
İstanbul Teknik Üniversitesi
Prof. Dr. Can Fuat DELALE
Işık Üniversitesi
Prof. Dr. Gülay DERELİ
Yıldız Teknik Üniversitesi
Prof. Dr. Bekir KARAOĞLU
Beykoz Lojistik MYO
Prof. Dr. Mustafa KESKİN
Erciyes Üniversitesi
Prof. Dr. Ş. Erol OKAN
Trakya Üniversitesi
Prof. Dr. Oktay SİNANOĞLU
Yale Üniversitesi
Prof. Dr. Yani SKARLATOS
Boğaziçi Üniversitesi
Prof. Dr. Bilal TANATAR
Bilkent Üniversitesi
Prof. Dr. Hasan TATLIPINAR
Yıldız Teknik Üniversitesi
Prof. Dr. Mehmet TOMAK
Ortadoğu Teknik Üniversitesi
Prof. Dr. İskender YILGÖR
Koç Üniversitesi
Prof. Dr. Ersin YURTSEVER
Koç Üniversitesi
SEMPOZYUM DÜZENLEME KURULU
Prof. Dr. Zehra AKDENİZ
Piri Reis Üniversitesi
Yrd. Doç. Dr. Zeynep ÇİÇEK ÖNEM
İstanbul Üniversitesi
Yrd. Doç. Dr. Ali KARAMAN
İstanbul Üniversitesi
Yrd. Doç. Dr. Gülşen AKIN EVİNGÜR
Piri Reis Üniversitesi
Hanifi ARSLAN
Piri Reis Üniversitesi
Sıvıhal Fiziği Çalışma Grubu
15. ULUSAL SIVIHAL FİZİĞİ SEMPOZYUMU
24-25 Kasım 2011
Piri Reis Üniversitesi, Tuzla-İstanbul
PROGRAM
24 Kasım 2011, Perşembe
09.30 – 10.30
Kayıt
10.30 – 11.25
Açılış Konuşmaları
Prof.Dr. Osman Kamil Sağ
( Piri Reis Üniversitesi Rektörü)
Prof.Dr. Zehra Akdeniz
(Piri Reis ÜniversitesiFen Edebiyat Fakültesi Dekanı,
Sıvıhal Fiziği Sempozyum Koordinatörü)
11.30 – 11:40
11.40 – 12.20
12.20 – 12.50
12.50 – 13.10
Denge,Deniz, Strateji, Rekabet
Dr. Mühendis Ekber Onuk
(Yonca Onuk Tersanesi)
BREAK / ARA
Denizin Farklı Kültürleri
Sargun A. Tont
(Sabancı Üniversitesi)
SU: Fiziği, Nanofiziği, Kimyası ve Jeopolitiği
Sondan Feyiz Durukanoğlu
(Sabancı Üniversitesi)
Denizlerdeki Biyolojik Kirlenmeyi Önlemek Amacıyla
Geliştirilen Poliolefin Kaplamalar ile Ulva Sporlarının
Yüzeylerden Uzaklaştırılması Arasındaki İlişki
İkrime Orkan Uçar, C. Elif Özen Cansoy, H. Yıldırım
Erbil
(Piri Reis Üniversitesi)
13.15 – 14.10
ÖĞLE YEMEĞİ
13:50 – 14.10
Bistability of a two- mode BEC in an optical cavity
S.Safaei, O.E.Mustecaplioğlu, B.Tanatar
(Bilkent Üniversitesi)
Computational design of metal borohydrides and metal
ammines for energy storage
Adem Tekin
14.10 – 14.40
14.40 – 15.10
15.10 – 15.55
16.00-
(İstanbul Teknik Üniversitesi)
Su Dalgalarının Modellenmesi ve Uygulamaları
Serdar Beji
(İstanbul Teknik Üniversitesi)
Araştırma ve Erişim Odaklı Eğitim
Nihat Berker
(Sabancı Üniversitesi)
SEMPOZYUM KOKTEYLİ
25 Kasım 2011, Cuma
09.40 – 10.00
10.00 – 10.20
10.20 – 10.40
10.40 – 11.00
Stability of spin-orbit coupled Fermi gases with
population imbalance
Levent Subaşı
(İstanbul Teknik Üniversitesi)
Sol-Gel Phase Transitions in Composite Gels
Gülşen Akın Evingür, Önder Pekcan
(Piri Reis Üniversitesi)
Quantum Phase Transitions in Atomic Condensates
Coupled to Driven Dissipative Optical Cavities
Özgür E. Müstecaplıoğlu
(Koç Üniversitesi)
Dynamical properties of a coupled nonlinear
dielectric waveguide surface-plasmon
josephson junction system
Yasa Ekşioğlu, Özgür E. Müstecaplıoğlu, Kaan
Güven
(Koç Üniversitesi)
BREAK / ARA
11.15 – 11.35
11.35 – 11.55
11:55 – 12.05
12.05 – 12.15
Çeşitli metal kümelerinin katı-sıvı faz geçişleri
Meral Eryürek, M. H. Güven
(Karaelmas Üniversitesi)
DFT study of rhenium-doped boron clusters: ReBn
(n=1-15)
Servet Kurt, M. Böyükata, Z. B. Güvenç
(Bozok Üniversitesi)
Part I. Experimental Study of Riboflavin-Dextran
and Riboflavin-Dextrin Solutions
Nur Mustafaoğlu, Gülşen A. Evingür, Buse Özen, F.
Gülay Acar, Gönül Özen
(İstanbul Teknik Üniversitesi)
Part II. Theoretical Study of Riboflavin-Dextran and
Riboflavin-Dextrin Solutions
Buse Özen, Nur Mustafaoğlu, Gülşen A. Evingür, F.
Gülay Acar, Gönül Özen
(İstanbul Teknik Üniversitesi)
12.30 – 13.40
ÖĞLE YEMEĞİ
13.40 – 14.00
Spontaneous Formation of A Nanotube From A
Square Ag Nanowire:
An Atomistic View
Mine Konuk, Sondan Feyiz Durukanoğlu
(İstanbul Teknik Üniversitesi)
Modifiye Aljinat Jellerinden Protein Salımı
Hakan Kaygusuz, F. Bedia Erim
(İstanbul Teknik Üniversitesi)
Embedded Atom Method Potential for Ni-Cu Alloys
and Its Applications for Ni, Cu growth on Cu(111)
Berk Onat, Sondan Feyiz Durukanoğlu
(İstanbul Teknik Üniversitesi)
14.00 – 14.20
14.20 – 14.40
BREAK / ARA
15.00 – 15.20
15.20 – 15.40
15.40 – 16.00
16.00 – 16.30
Ground-state configurations of few interacting
bosons confined in two dimensions
by anisotropic harmonic potential.
A. İhsan Meşe, Pablo Capuzzi, Saban Aktaş,
Zehra Akdeniz, S.Erol Okan
(Trakya Üniversitesi)
Density of State and Localization Properties in
Optical Lattices with Speckle
Disorder
Serpil Sucu, Saban Aktaş, S.Erol Okan, Zehra
Akdeniz, Patrizia Vignolo
(Trakya Üniversitesi)
The potential profile of quantum well under the laser
and electric fields
Figen Karaca Boz, Saban Aktas, Şevket Erol
Okan
(Trakya Üniversitesi)
Denizlerdeki Hazine
Gülaçtı Topçu
(Bezmialem Vakıf Üniversitesi)
Denge,Deniz, Strateji, Rekabet
Dr. Mühendis Ekber Onuk
Yonca Onuk Tersanesi
Denizin Farklı Kültürleri
Sargun A. Tont
Sabancı Üniversitesi
SU: Fiziği, Nanofiziği, Kimyası ve Jeopolitiği
Sondan Durukanoğlu Feyiz
Sabancı Üniversitesi
21. yüzyılda petrölün yerini alabileçeğinin tartışıldığı şu günlerde
su'ya yaşamsal değerinin yanında ekonomik değer de eklenince, su
hemen hemen her türlü ekonomik aktvitenin içersinde yer alır oldu. Bu
önem, su'yu bir cok bilimsel ve sosyo-ekonomik projelerin ilgi odağına
koydu. Bu konuşmamda değişik perspektiflerden bakarak, doğanın
bize sunduğu ve kaygusuzca tüketmeye devam ettiğimiz suyu tanıtmaya
çalışacağım.
Denizlerdeki Biyolojik Kirlenmeyi Önlemek Amacıyla
Geliştirilen Poliolefin Kaplamalar ile Ulva Sporlarının
Yüzeylerden Uzaklaştırılması Arasındaki İlişki
İkrime ORKAN UÇAR,2 C. Elif ÖZEN CANSOY1 ve H. Yıldırım
ERBİL2
1
Piri Reis Üniversitesi, İstanbul, Türkiye
[email protected]
2
Gebze Yüksek Teknoloji Enstitüsü, Kimya Mühendisliği Bölümü, Kocaeli, Türkiye
[email protected], [email protected]
Deniz ortamı ile temas halinde olan yüzeyler üzerinde mikroorganizmalar, algler ve diğer deniz
canlılarının tutunması sonucunda biyolojik kirlenme meydana gelir. Biyolojik kirlenmenin sonucunda,
gemilerin hızında, manevra kabiliyetlerinde ve yakıt tüketimlerinde olumsuz etkiler ortaya çıkar. Biyolojik
kirlenmeyi ve bunun beraberinde getirdiği olumsuz etkileri ortadan kaldırabilmek için gemi boyalarının
yüzey serbest enerjisi1, mekanik özellikleri1, ıslanabilirliği2 ve pürüzlülüğü3,4 gibi özellikleri değiştirilerek
daha az kirlenen boyalar sentezlenebilir. Islanabilirlik önemlidir ve o yüzeyin kimyasal kompozisyonu ve
pürüzlülüğü değiştirilerek kontrol edilebilir. Yüzeyin geometrik mikro yapısının kontrolü de deniz
ortamında biyolojik türlerin yüzeylere yapışmasını engellemede önemli rol oynar. Bu çalışmanın 5 amacı
serbest yüzey enerjisi değerleri birbirine yakın olan poliolefin polimer ve kopolimerler kullanarak
hazırlanan mikro desenli yüzeylerin temas açısı histeresizi (CAH) ve ıslanabilirlik histeresizi (WH) değişimi
ile deniz ortamındaki türlerin (Ulva sporları) yüzeylerden uzaklaştırılması arasındaki ilişkiyi incelemektir.
Bu amaçla, polipropilen (PP) ve yüksek yoğunluklu polietilen (HDPE) polimerleri ile polipropilenpolietilen (PPPE) ve etilen-vinil asetat (EVA-12; 12% VA) kopolimerleri kullanılarak yüzeyler
sentezlenmiştir. Ulva sporlarının yüzeylerden uzaklaştırılabilme özellikleri ile polimer ve kopolimer
yüzeylerinin temas açıları ve ıslanabilirlik histeresizleri arasında doğrusal bir ilişki olduğu bulunmuştur.
Ulva sporlarının yüzeylerden uzaklaştırılabilme kolaylıkları PP > HDPE > PPPE > EVA-12 şeklindedir ve
histeresizdeki (CAH ve WH) artış sporların yüzeylerden uzaklaştırılma yüzdelerinin artmasına neden
olmaktadır.
Referanslar
1.
R. F. Brady and I. L. Singer, Biofouling 15, 73 (2000)
2.
M. E. Callow, J. A. Callow, L. K. Ista, S. E. Coleman, A. C. Nolasco, and G. P. Lopez, Appl.
Environ. Microbiol. 66, 3249 (2000).
3.
J. Genzer and J. Groenewold, Soft Matter 2, 310 (2006).
4.
J. F. Schumacher, M. L. Carman, T. G. Estes, A. W. Feinberg, L. H. Wilson, M. E. Callow, J. A.
Callow, J. A. Finlay, and A. B. Brennan, Biofouling 23, 55 (2007).
5.
Ikrime O. Ucar, C. Elif Cansoy, H. Yildirim Erbil, Michala E. Pettitt, Maureen E. Callow, and
James A. Callow, Biointerphases, 5(3), 75-84 (2010).
Bistability of a two- mode BEC in an optical cavity
S.Safaei, O.E.Mustecaplioğlu, B.Tanatar
Bilkent Üniversitesi
We use the self-consistent mean-field theory to analyze the effects of Rashba-type
spin-orbit coupling (SOC) on the ground-state phase diagram of populationimbalanced Fermi gases throughout the BCS-BEC evolution. We find that the
SOC and population imbalance are counteracting, and that this competition tends
to stabilize the uniform superfluid phase against the phase separation. However,
we also show that the SOC stabilizes (destabilizes) the uniform superfluid phase
against the normal phase for low (high) population imbalances. In addition, we
find topological quantum phase transitions associated with the appearance of
momentum space regions with zero quasiparticle energies, and study their
signatures in the momentum distribution.
Computational design of metal borohydrides and metal ammines
for energy storage
Adem Tekin
Informatics Institute, Istanbul Technical University, 34469 Maslak Istanbul Turkey
By combining several computational methods, the lowest energy crystal structures
of Mg(NH3)nCl2 with n=6,2,1, Mg(BH4)2, LiBH4 and NaBH4 were searched. Furthermore,
NH3 ab- and desorption mechanisms involved in metalammines were investigated
using a combination of DFT and quasi-elastic neutron scattering measurements.
Stability of spin-orbit coupled Fermi gases with
population imbalance
Levent Subaşı
İstanbul Teknik Üniversitesi, İstanbul
We use the self-consistent mean-field theory to analyze the effects of Rashbatype spin-orbit coupling (SOC) on the ground-state phase diagram of
population-imbalanced Fermi gases throughout the BCS-BEC evolution. We
find that the SOC and population imbalance are counteracting, and that this
competition tends to stabilize the uniform superfluid phase against the phase
separation. However, we also show that the SOC stabilizes (destabilizes) the
uniform superfluid phase against the normal phase for low (high) population
imbalances. In addition, we find topological quantum phase transitions
associated with the appearance of momentum space regions with zero
quasiparticle energies, and study their signatures in the momentum
distribution.
SU DALGALARININ MODELLENMESİ VE
UYGULAMALARI
S. Beji
İstanbul Teknik Üniversitesi, Gemi İnşaatı ve Deniz Bilimleri
Fakültesi
Maslak 34469, İstanbul
Su dalgalarının modellenmesi için derinlik integre edilmiş denklemlerin
türetilmesi, çeşitleri ve kullanım alanları incelenmektedir. Diğer yaklaşımlara
göre derinlik integre edilmiş dalga modellerinin üstünlükleri belirtilerek farklı
uygulamalara ait örnek simülasyonlar verilmektedir. Kıyı ve liman
bölgelerindeki dalga hareketleri, deniz dibinden su yüzeyine uzanan yapılara
etkiyen dalga kuvvetleri ve tsunami simülsayonları gibi uygulamalar
örneklerle gösterilmektedir.
Araştırma ve Erişim Odaklı Eğitim
Nihat Berker
Sabancı Üniversitesi
Sol- Gel Phase Transitions in Composite Gels
Gülşen Akın Evingür1and Önder Pekcan2
1
Piri Reis University, 34940, Tuzla, Istanbul, TURKEY, [email protected]
2
Kadir Has University, 34083, Cibali, Istanbul, TURKEY, [email protected]
The composite gels were prepared with different amounts of monomers such as
kappa- carrageenan (κC), N- isoproplacrylamide (NIPA), multiwalled carbon
nanotube (MWNT) and sodium alginate (SA) in polyacrylamide (PAAm). The sol- gel
phase transitions in the composite gels were characterized by the steady state
fluorescence technique (SSF). Pyranine was added as a fluoroprobe for monitoring the
polymerization. Pyranine added to the pre-polymerization solution presented a
spectral shift to the shorter wavelengths upon the initiation of polymerization. This
spectral shift is due to the binding of pyranine to the polymer chains during the
composite polymerization. The fluorescence intensity of the pyranine bonded to the
strands of the composite gels allows one to measure directly the gel fraction and
average degree of polymerization near the sol-gel phase transition.
In this study, we aimed to study the gelation of the composites and determined the gel
fraction exponent, β and the weight average degree of polymerization exponent, γ for
this composite system. For this purpose, the aqueous solutions of various monomers’
composites were prepared. The universality of composite gels could be described by
classical and percolation exponents during the sol-gel phase transition in PAAm-κC
[1], PAAm- NIPA[2], PAAm-MWNT [3] and PAAm- SA[4]. It is found that the
critical exponents did not obey the same universality class, where the most important
factor is the monomer content in which the exponents differ drastically from
percolation to the classical values in the composite gels.
References
[1] D. Kaya Aktaş, G. Akın Evingur, Ö. Pekcan, Universal Behaviour of Gel
formation from Acrylamide-Carrageenan Mixture around the Gel Point: A
Fluorescence Study. Journal of Biomolecular Structure and Dynamics, 2006.
24(1): p. 83- 90.
[2] G. Akın Evingur, D. Kaya Aktaş Ö. Pekcan, Steady state fluorescence technique
for studying phase transitions in PAAm- PNIPA mixture. Phase Transitions,
2009. 82(1): p. 53-65.
[3] D. K.Aktaş, G. Akın Evingur, Ö. Pekcan, Critical exponents of gelation and
conductivity in Polyacrylamide gels doped by multiwalled carbon nanotubes.
Composite Interfaces, 2010. 17: p. 301-318.
[4] G. A. Evingür, F. Tezcan, F. B. Erim and Ö. Pekcan, Monitoring the Gelation of
Polyacrylamide - Sodium Alginate Composite by Fluorescence Technique, Phase
Transitions, 2011, in press.
Quantum Phase Transitions in Atomic
CondensatesCoupled to Driven Dissipative Optical
Cavities
Özgür E. Müstecaplıoğlu
(Koç Üniversitesi)
We examine structural dynamical phase transition of an ultracold gas of bosonic
atoms coupled to a driven dissipative optical cavity. The atomic condensate is pumped
along the direction transverse to the cavity axis. Above a certain threshold of the
pumping strength, the condensate undergoes a dynamical quantum phase transition
where the continuous translational symmetry is broken and a crystalline structure is
emerged. Atomic phase transition is accompanied by quantum phase transition of the
cavity photons. Cavity field exhibits so called Dicke superradiance phase transition.
The governing equations of the system describe the coupled cavity field and
condensate field dynamics. Imaginary and Real time simulations are performed to
solve the system of equations. The results are shown to be in agreement with the
actual experiment [1]. In addition we analyse the collective excitations of the coupled
field-condensate system. Photodetection methods, stochastic resonances and
excitations and hierarchy of multipole excitations are discussed.
[1] K. Baumann, C. Guerlin, F. Brennecke and T. Esslinger, arxiv:0912.3261 [quantph].
Dynamical properties of a coupled nonlinear dielectric
waveguide surface-plasmonjosephson junction system
Yasa Eksioglu, Ozgur E. Mustecaplioglu, Kaan Guven
We demonstrate that a weakly-coupled nonlinear dielectric waveguide
surface-plasmon (DWSP-JJ) system can be formulated as in analogy to
bosonic Josephson junction of atomic condensates at very low temperatures
yet exhibits different dynamical features. Such a system can be realized along
a metal - dielectric interface where the dielectric medium hosts a nonlinear
waveguide (e.g. fiber) for soliton propagation. The inherently dynamic
coupling parameter generates novel features in the phase space.
ÇEŞİTLİ METAL KÜMELERİNİN KATI-SIVI FAZ GEÇİŞLERİ
M..ERYUREK, M. H. GUVEN
Zonguldak Karaelmas Üni.Fen-Ed. Fak. Fiz. Böl.,Zonguldak,TÜRKİYE
[email protected], [email protected]
Parçacıklar arası etkileşmeleri Gupta Potansiyeli ile tanımlanan çeşitli metal
kümelerinin mikrokanonik Moleküler Dinamik simülasyon yöntemi ile katı-sıvı faz
geçişleri incelenmiştir. Bu süreçte ilk aşamada her bir sabit enerji değerine karşılılık
gelen simülasyonlara ait potansiyel enerjiler, kinetik sıcaklıklar ve kümedeki
atomların koordinatları hesaplanmıştır. İkinci aşamada elde edilen sonuçlar
kullanılarak kalorik eğriler ile bağ uzunluğundaki dalgalanmaların kare
ortalamalarının kare kökü eğrileri elde edilmiştir. Üçüncü aşamada ise iki farklı
yöntem kullanılarak, kanonik ve mikrokanonik termodinamik (ısı kapasitesi, entropi,
termodinamik sıcaklık, potansiyel enerji dağılımı) nicelikler elde edilmiştir. Bu
sonuçlardan kümelerin katı-sıvı faz geçişlerinin özellikleri ve erime sıcaklıklarının
belirlenmesinde yararlanılmıştır. Çalışma; entropi eğrilerinden elde edilen potansiyel
enerji dağılım fonksiyonlarının davranışının, faz geçişlerinin karakteristiğini
belirlemek için kullanışılı bir yöntem olduğu görüşüne ulaşılmasını sağlamıştır.
DFT study of rhenium-doped boron clusters: ReBn (n=1-15)
S. KURT1, M. BÖYÜKATA1, Z. B. GÜVENÇ2
1
Department of Physics, Bozok University, 66200 Yozgat, Turkey
2
Department of Elect. and Comm. Eng., Çankaya University, 06530 Ankara,
Turkey
Bare boron [1] and metal-doped boron [2,3] clusters have been an interesting subject
in nanosized finite cluster studies due to the importance for hydrogen hosting [4].
There are also considerable interest on Rhenium clusters, Ren (n=1-8), [5] and Re-B
binary clusters [6] owing to their potential applications in constructing nanostructured
materials. In this preliminary work the geometry optimizations have been carried out
for Re doped boron microclusters, ReB n (n=1-15), by using DFT/B3LYP functional
and Cep-4G basis set [7]. Structural and energetic analysis have been realized for the
obtained possible lower-lying energy configurations. The results are compared with
pure Bn clusters and any boron-metal complexes.
Acknowledgment. This work is supported by Bozok University (BAP-I.F.E.F/2011-32)
References
[1] Atış, M., Özdoğan, C., Güvenç, Z.B., J. Quantum Chem., 107, 3, 729, (2007).
[2] Liu, X., Zhao, G.F., Guo, L.J., Jing, Q., Luo, Y.H., Phys. Rev. A 75, 063201, (2007).
[3] Böyükata, M., Güvenç, Z.B., J. Alloys Comp. 509, 4214 (2011).
[4] Böyükata, M., Güvenç, Z.B., Int. J. Hydrogen Energy 36, 8392 (2011).
[5] Feng, X.J., Cao, T.T., Zhao, L.X., Lei, Y.M., Luo, Y.H., Eur. Phys. J. D 50, 285 (2008).
[6] Feng, X.J., Zhao, L.X., Cao, T.T., Lei, Y.M., Luo, Y.H., Physica B 403, 432, (2008).
[7] Frisch M. J. et. al., GAUSSIAN 03, Revision D.01, Gaussian Inc., Wallingford, CT,
(2004).
Part I. Experimental Study of Riboflavin – Dextran and
Riboflavin – Dextrin Solutions
Nur Mustafaoğlu1, Gülşen Akın Evingür2, BuseÖzen3 ,F. Gülay Acar4*,
Gönül Özen4
1
İstanbul Technical University, Institute of Science and Technology, Nano Science and
Nano Engineering, 34469 İstanbul, Turkey
2
Piri Reis University, 34940, Tuzla, Istanbul, Turkey
3
İstanbul Technical University, Institute of Science and Technology, Physics
Engineering,
34469Maslak, İstanbul, Turkey
4
İstanbul Technical University, Faculty of Sciences and Letters, Physics Engineering
Department,
34469 İstanbul, Turkey
*
[email protected]
Riboflavin is B2 vitamin and both dextrin and dextran are polysaccharide. The only
difference between dextrin and dextran is their linked; in dextran α-(1,3) and α-(1,6)
linked exists between α-D-glucopyranosyl residues while in dextrin α-(1,4) or α-(1,6)
glycosidic bonds are existed. The length of the dextran molecule is between 10000 Da
and 150000 Da which is appropriate for the cross-linking reaction in biological
systems and polymeric gels. Dextrin is derived from potato which color is white and
has similar properties with dextran to use in cross-linking reactions.
In this study, absorption spectrum and fluorescence spectrum of both riboflavin –
dextran and riboflavin – dextrin solutions for different concentrations from 0,01 to 1
M have been measured. Furthermore, time-drive measurement and analysis of the
solutions have been investigated. According to results from the experiments, physical
parameters of the solutions such as diffusion coefficient and quantum yield have been
calculated. Comparison of these two solutions has been shown as tables and
graphics.The theoretical model andcalculations are going to be presented in our other
presentation that explains the theoretical part of our study.
Part II. Theoretical Study of Riboflavin – Dextran and
Riboflavin – Dextrin Solutions
Buse Özen1, Nur Mustafaoğlu2, Gülşen Akın Evingür3, F. Gülay Acar4*,
Gönül Özen4
1
İstanbul Technical University, Institute of Science and Technology, Physics
Engineering,
34469Maslak, İstanbul, Turkey
2
İstanbul Technical University, Institute of Science and Technology, Nano Science and
Nano Engineering, 34469 İstanbul, Turkey
3
Piri Reis University, 34940, Tuzla, Istanbul, Turkey
4
İstanbul Technical University, Faculty of Science and Letters, Physics Engineering
Department, 34469Maslak, İstanbul, Turkey
*
[email protected]
In this study theoretical modelling has been done after our experiments that have been
conducted in order to determine the physical parameters about the specific chemical
solutions.
Riboflavin-Dextran and Riboflavin-Dextrin solutions have the ability to create
crosslinks between fibrilles in the biological tissues.These solutions cause the
generation of free oxygen radicals by the excitement of UV light without harming the
biological tissues. These oxygen radicals are formed to tide amino groups of the
collagen fibrilles by covalent bond.Hence, interfibrilles cross-linking enhances the
resistant and rigidity.
These solutionswere compared in order to decide which one has more advantage than
the other one. According to the results of ourexperiments, similar absorption and
emission spectras were obtained for both of these two solutions. Riboflavin-Dextran
and Riboflavin-Dextrin solutions were compared by the help of graphics and the
physical parameters such as cure depth and diffusion coefficient. Physical parameters
were calculated in a theoretical diffusion model. The emmision and absorption
graphics are going to be presented in our other presentation that explains the
experimental part of our study.
This study will lead to cure the biological tissues and will be the additional treatment
for compliance process after organ transplantation.
Spontaneous Formation of A Nanotube From A Square
Ag Nanowire:
An Atomistic View
M. Konuk1, S. Durukanoglu2, 3
1
Department of Physics, Istanbul Technical University, Maslak, 34469
Istanbul, Turkey
2
Faculty of Engineering and Natural Sciences, Sabanci University, Orhanli,
Tuzla 34950 Istanbul, Turkey
3
Nanotechnology Research and Application Center, Sabanci University,
Orhanli, Tuzla 34950 Istanbul, Turkey
We have performed molecular static calculations to investigate the recently observed
phenomenon of the spontaneous formation of a nanotube from a regular, square Ag
nanowire[1,2]. In the simulations, atoms are allowed to interact via the model
potential obtained from the modified embedded atom method[3]. Our simulations
predict that this particular type of structural phase transformation is controlled by the
nature of applied strain, length of the wire and initial cross-sectional shape. For such a
perfect structural transformation, the <100> axially oriented fcc nanowire needs (1) to
be formed by stacking A and B layers of an fcc crystal, both possessing the geometry
of two interpenetrating one-lattice-parameter-wide squares, containing four atoms
each, (2) to have an optimum length of eight layers, and (3) to be exposed to a
combination of low and high stress along the length direction. The results further offer
insights into atomistic nature of this specific structural transformation into a nanotube
with the smallest possible cross-section.
This work was supported by TUBITAK under Grant No. 109T105. Computations
were carried out through UYBHM at Istanbul Technical University, under Grant No.
20132007.
[1] M. J. Lagos, F. Sato, J. Bettini, V. Rodrigues, D. S. Galvao, and D. Ugarte, Nature
Nanotech. 4, 149 (2009).
[2] P. A. S. Autreto, M. J. Lagos, F. Sato, J. Bettini, A.R. Rocha, V. Rodrigues, D. Ugarte and
D. S. Galvao, Phys. Rev. Lett. 106, 065501 (2011).
[3] M. I. Baskes, Phys. Rev. B 46, 2727-2742, (1992); B-J Lee., J-H Shim, and M. I. Baskes,
Phys. Rev. B 68, 144112 (2003).
ModifiyeAljinat Jellerinden Protein Salımı
Hakan Kaygusuz, F. Bedia Erim
İstanbul Teknik Üniversitesi
Bir polisakkarit olan aljinat, çok değerlikli katyonlar ile suda çözünmeyen jeller
oluşturmaktadır. Bu jeller amaca uygun olarak modifiye edilebilir. Bu amaçlar
arasında ilaç salım denemeleri de yer almaktadır. Bu çalışmada kil katkılı kalsiyum
aljinat kürelerinin insan vücuduna sindirim yoluyla alımı taklit edilerek, model protein
olarak seçilmiş sığır serumu albümininin çeşitli çözeltilere salımı incelenmiştir.
Hazırlanan küreler karakterize edilmiş ve salım ortamlarındaki davranışları da takip
edilmiştir.
Embedded Atom Method Potential for Ni-Cu Alloys and Its
Applications for Ni, Cu growth on Cu(111)
Berk Onat1, Sondan Durukanoğlu2,3
1
2
Informatics Institute, İstanbul Technical University, 34469, İstanbul, Turkey
Faculty of Engineering and Natural Sciences, Sabancı University, 34956, İstanbul,
Turkey
3
Nanotechnology Research and Application Center, Sabancı University, 34956,
İstanbul, Turkey
We developed a semi-empirical, many-body type model potential to investigate static
and dynamic properties of Ni-Cu alloys. The formalism is based on the embedded
atom method [1] with improved optimization techniques. The Ni-Cu alloy potential
was determined by fitting to data on lattice parameters, cohesive energies for L1 0, L11,
L12, and L13 phases, together with vacancy formation energies, bulk modulus and
elastic properties for L12, L13 phases. Our preliminary calculations for energy barriers
for the diffusing Ni and Cu atoms on Cu(111) based on the nudged elastic band
method are found to be consistent with the available experimental and other
theoretical results. Our ultimate goal is to describe the varying characteristics in
growing islands of pure Cu, Ni atoms and mixed Ni-Cu combinations on Cu(111) [2].
[1] Voter A. F., and Chen S. P., Mat. Res. Soc. Symp. Proc., 82, 175, (1987)
[2] S. Pons et al., Surf. Sci., 511, 449, (2002)
This work was supported by TUBITAK under Grant No. 109T105. Computations
were carried out through UYBHM at Istanbul Technical University, under Grant No.
20132007.
Ground-state configurations of few interacting bosons confined in
two dimensions by anisotropic harmonic potential
A.I. Mese1, P.Capuzzi2, S.Aktas1, Z. Akdeniz3 and S.E.
Okan1
1
Department of Physics, Trakya University, 22030 Edirne,
Turkey
2
Instituto de F´ısica de Buenos Aires, Consejo Nacional de
Investigaciones Cient´ıficas y T´ecnicas, Argentina
3
Piri Reis University, 34940 Tuzla, Istanbul, Turkey
We studied the ground-state configurations of few bosons confined by a two
dimensional anisotropic harmonic potential and K0 interaction potential [1] relying on
a minimal variational approach based in Gaussian wave functions. The ground state
energies and the density profiles have been obtained for the systems of bosonic
Rubidium atoms with their number ranging from two to nine [2]. It has been shown
that the bosonic atoms are driven from a two dimensional configuration to that of one
dimensional, if the anisotropy parameter is small. In addition, the transition criterions
between Bose-Einstein Condensate and Wigner Crystallization have been determined
by developing an analytical method[3]. The results obtained are compared with the
published numerical and experimental results [4,5].
References
[1] Nelson D.R., and Seung H.S., Phys. Rev. B. 39 9153 (1989).
[2] A. I. Mese, P. Capuzzi, Z.Akdeniz, S.E.Okan and M.P. Tosi J.Phys. 20 335222,
2008
[3] A.I.Mese, P.Capuzzi,S.Aktas,Z.Akdeniz and S.E.Okan Phys. Rev.A 84, 043604
(2011)
[4] S. W. S. Apolinario,et al., Phys. Rev. E 72, 046122 2005
[5] M Saint Jean and C Guthmann, J. Phys. Condens. Matter 14, 13653 2002
Density of State and Localization Properties in Optical Lattices
with Speckle Disorder
Serpil Sucu1, Saban Aktaş1, S.Erol Okan1, Zehra Akdeniz2, Patrizia Vignolo3
1
Department of Physics, Trakya University,22030, Edirne
2
Piri Reis University, 34940 Tuzal-İstanbul, Edirne
3
Universite de Nice-Sophia Antipolis, Institut non Lineaire de Nice, CNRS, 1361 route
des Lucioles, 06560 Valbonne, France
We study the localization properties and density of state of non-interacting wawes
propagating in a speckle-like potential superposed on a one-dimensional lattice. To
study the effect of a speckle potential in the presence of a 1D lattice on matter-wave
transport we use the 1D tight-binding Hamiltonian where site energies are squaresinc-correlated random variables. By decreasing the width of the correlation
function, the disorder patterns approaches a  -correlated disorder, and the
localization length becomes almost energy-independent in the strong disorder limit.
We show that at fixed and large disorder strength, the localization efficacy of the
speckle potential depends strongly on the width of the auto-correlation function w .
The potential profile of quantum well under the laser and electric
fields.
Figen Karaca Boz1 , Saban Aktas,1* and Sevket Erol Okan1
Department of Physics, Trakya University, Edirne 22030, Turkey
1
The potential profile in the various quantum wells is investigated under the laser, and electric fields. The
calculations are made by using finite different and variational methods within the effective-mass
approximation. It can also be seen that the shape of potential profiles of quantum well becomes important
as the differences between binding energies emphasized more when the electric and laser fields are
applied in comparison with the presence of the electric field only. In recent years, the many studies
related to the external fields acting on the binding energy in a single and double quantum wells have been
reported [1-11]. An external electric field application to these structures causes a polarization on the
carrier distribution. The binding energy in the quantum well can be decreased or increased depending on
the location of the impurity and the electric field direction applied. The joint action of a laser and electric
field on the binding energy is depended on the strength of the fields in the quantum well. In this work, we
will focus on studying the potential profile of the various quantum well under the laser and electric fields.
The binding energy of the impurity in the various quantum wells is investigated under the laser, and
electric fields. Fig. 1 shown effect of the combination of laser and electric fields on the potential profile in
double parabolic quantum well (DPQW), and double square quantum well (DSQW) in the z-direction.
300
DPQW
DSQW
F=20kV/cm
o
=25A
250
9,0
DPQW
DSQW
0=25 A
8,5
EB(meV)
VD(meV)
200
150
100
zi=0
o
zi(LA+LB)/2
8,0
zi(LA+LB)/2
50
7,5
0
b
-150
-100
-50
0
50
100
150
o
z(A )
Fig. 1. The potential profile of the DPQW, and
DSQW in the z-direction for α0=25Ao under the
electric field F=20kV/cm, the dimensions are
LA=50Ao and LB=25Ao.
0
5
10
15
20
25
F(kV/cm)
Fig. 2. The binding energy of the DPQW, and
DSQW structures as a function of the electric field
for different the impurity position. In the laser field
parameter is α0=25Ao.
The effect of the electric field on the binding energy in DPQW, and DSQW with LA=50Ao and LB=25Ao is
calculated for different impurity positions in Fig. 2 with laser field. In summary, we showed that the shape
of potential profiles of quantum wells becomes important as the differences between binding energies
emphasized more when the electric and laser fields are applied in comparison with the presence of the
electric field only.
.*Corresponding author: [email protected]
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[2] E. Kasapoğlu, H Sari., I. Sökmen. Physica B 390 (2007) 216.
[3] E. Kasapoglu, I. Sökmen, Physica E 27 (2005)198.
[4] Q. Fanyao, A. L. A. Fonseca, and O. A. C. Nunes, Phys. Stat. Sol. 8b) 197 (1996) 349.
[5] O. A. C. Nunes, A. L. A. Fonseca, F. M. S. Lima, D. A. Agrello, Solid State Communications 122
(2002) 425.
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Physical Review B 75 (2007) 073201.
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[8] L. M. Burileanu, E. C. Niculescu, N. Eseanu, A. Radu, Physica E 41 (2009) 86.
[9] E. C. Niculescu, A. Radu, M. Stafe, Superlattices and microstructures 46 (2009) 443.
[10] N. Eseanu, Physics Letters A 374 (2010) 1278.
[11] E. C. Niculescu, N. Eseanu, Superlattices and microstructures 48 (2010) 416.