http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Advances in stable and flexible perovskite solar cells
Qamar Wali,Faiza Jan Iftikhar,Naveen Kumar Elumalai,Yaseen Iqbal,Sidra Yousaf,Shahid Iqbal,Rajan Jose 한국물리학회 2020 Current Applied Physics Vol.20 No.5
Roll-to-roll (R2R) production is an innovative approach and is fast becoming a very popular industrial method for high throughput and mass production of solar cells. Replacement of costly indium tin oxide (ITO), which conventionally has served as the transparent electrode would be a great approach for roll to roll production of flexible cost effective solar cells. Indium tin oxide (ITO) and fluorine-doped tin oxide (FTO) are brittle and ultimately limit the device flexibility. Perovskite solar cells (PSCs) have been the centre of photovoltaic research community during the recent years owing to its exceptional performance and economical prices. The best reported PSCs fabricated by employing mesoporous TiO2 layers require elevated temperatures in the range of 400–500 °C which limits its applications to solely glass substrates. In such a scenario developing flexible PSCs technology can be considered a suitable and exciting arena from the application point of view, them being flexible, lightweight, portable, and easy to integrate over both small, large and curved surfaces.
Effect of post treatments on the structure and thermal stability of titanate nanotubes
Qamar, M,Yoon, C R,Oh, H J,Kim, D H,Jho, J H,Lee, K S,Lee, W J,Lee, H G,Kim, S J IOP Pub 2006 Nanotechnology Vol.17 No.24
<P>TiO<SUB>2</SUB> sol was prepared hydrothermally in an autoclave from aqueous TiOCl<SUB>2</SUB> solutions as a starting precursor. Titanate nanotubes were obtained when the sol–gel-derived TiO<SUB>2</SUB> sol was treated chemically with a 10?M NaOH solution and subsequently heated in the autoclave at 150 ?C for 48?h. The samples were characterized using XRD, TEM, SEM, EDX, Raman spectroscopy, and a BET surface area analyser. The effect of post treatments, such as washing with and without hydrochloric acid and calcination, on the phase structure, shape and morphology, pore structures, and BET surface area of the titanate nanotubes was investigated. When a sample containing 7.08?wt% Na (after washing only with water) was calcined at different temperatures from 300 to 900 ?C, it showed the formation of a mixture of sodium trititanates and sodium hexatitanates and was found to preserve the tubular morphology at higher temperatures. However, a sample containing 0.06?wt% Na obtained after prolonged washing with hydrochloric acid followed by heat treatment showed the formation of TiO<SUB>2</SUB> anatase involving TiO<SUB>2</SUB> (B) as an intermediate at lower temperatures and anatase was further transformed to the rutile phase when the temperature was raised. On the basis of different observations, a general formula Na<SUB><I>x</I></SUB>H<SUB>2−<I>x</I></SUB>Ti<SUB>3</SUB>O<SUB>7</SUB>?<I>n</I>H<SUB>2</SUB>O has been proposed for the trititanate nanotubes.</P>
Qamar, Imteyaz,Park, Eunsook,Gong, Eun-Yeung,Lee, Hyun Joo,Lee, Keesook American Society for Biochemistry and Molecular Bi 2009 The Journal of biological chemistry Vol.284 No.27
<P>ARR19 (androgen receptor corepressor of 19 kDa), which encodes for a leucine-rich protein, is expressed abundantly in the testis. Further analyses revealed that ARR19 was expressed in Leydig cells, and its expression was differentially regulated during Leydig cell development. Adenovirus-mediated overexpression of ARR19 in Leydig cells inhibited testicular steroidogenesis, down-regulating the expression of steroidogenic enzymes, which suggests that ARR19 is an antisteroidogenic factor. Interestingly, cAMP/luteinizing hormone attenuated ARR19 expression in a fashion similar to that of GATA-1, which was previously reported to be down-regulated by cAMP. Sequence analysis of the Arr19 promoter revealed the presence of two putative GATA-1 binding motifs. Further analyses with 5' deletion and point mutants of putative GATA-1 binding motifs showed that these GATA-1 binding sites were critical for high promoter activity. CREB-binding protein coactivated GATA-1 and markedly increased the activity of the Arr19 promoter. Both GATA-1 and CREB-binding proteins occupied the GATA-1 motifs within the Arr19 promoter, which was repressed by cAMP treatment. Altogether, these findings demonstrate that ARR19 is the target gene of GATA-1 and suggest that ARR19 gene expression in testicular Leydig cells is regulated by luteinizing hormone/cAMP signaling via the control of GATA-1 expression, resulting in the control of testicular steroidogenesis.</P>
Discretization of laser model with bifurcation analysis and chaos control
Qamar Din,Waqas Ishaque,Iqra Maqsood,Abdelouahed Tounsi Techno-Press 2023 Advances in nano research Vol.15 No.1
This paper investigates the dynamics and stability of steady states in a continuous and discrete-time single-mode laser system. By using an explicit criteria we explored the Neimark-Sacker bifurcation of the single mode continuous and discrete-time laser model at its positive equilibrium points. Moreover, we discussed the parametric conditions for the existence of period-doubling bifurcations at their positive steady states for the discrete time system. Both types of bifurcations are verified by the Lyapunov exponents, while the maximum Lyapunov ensures chaotic and complex behaviour. Furthermore, in a three-dimensional discrete-time laser model, we used a hybrid control method to control period-doubling and Neimark-Sacker bifurcation. To validate our theoretical discussion, we provide some numerical simulations.
Qamar, M,Kim, S J,Ganguli, A K IOP Pub 2009 Nanotechnology Vol.20 No.45
<P>Titanate nanotubes containing 2.5 wt% Ni were synthesized from TiO<SUB>2</SUB> sol using alkali hydrothermal treatment followed by a simple ion-exchange process. The changes in phase, shape and morphology, surface area, and photocatalytic activity of these nanotubes have been explored as a function of calcination temperature. The samples were characterized using standard techniques, including x-ray diffraction, transmission electron microscopy, scanning electron microscopy, inductively coupled plasma spectrometry, energy dispersive x-ray spectroscopy, and Brauner–Emmett–Teller surface area analysis. The study revealed that the titanate phase containing Ni ions can be converted to the anatase phase after certain heat treatments but, at the same time, the tubular morphology was partially lost. Investigation of photocatalytic properties demonstrated that the as-prepared Ni–titanate nanotubes were photocatalytically inactive, but when heated at temperatures below 500 °C their activity was significantly enhanced with the change in phase. The calcined nanotube samples carrying nickel ion showed better photocatalytic activity than calcined nanotube samples containing protons. The hydrogen adsorption capacity of these titanates has also been measured, and it was found that Ni–titanate nanotubes can adsorb more hydrogen than its counterpart Na–titanate. </P>
Big Data Management System for Biomedical Images to Improve Short-term and Long-term Storage
Qamar, Shamweel,Kim, Eun Sung,Park, Peom The Korean Society of Systems Engineering 2019 시스템엔지니어링학술지 Vol.15 No.2
In digital pathology, an electronic system in the biomedical domain storage of the files is a big constrain and because all the analysis and annotation takes place at every user-end manually, it becomes even harder to manage the data that is being shared inside an enterprise. Therefore, we need such a storage system which is not only big enough to store all the data but also manage it and making communication of that data much easier without losing its true from. A virtual server setup is one of those techniques which can solve this issue. We set a main server which is the main storage for all the virtual machines(that are being used at user-end) and that main server is controlled through a hypervisor so that if we want to make changes in storage overall or the main server in itself, it could be reached remotely from anywhere by just using the server's IP address. The server in our case includes XML-RPC based API which are transmitted between computers using HTTP protocol. JAVA API connects to HTTP/HTTPS protocol through JAVA Runtime Environment and exists on top of other SDK web services for the productivity boost of the running application. To manage the server easily, we use Tkinter library to develop the GUI and pmw magawidgets library which is also utilized through Tkinter. For managing, monitoring and performing operations on virtual machines, we use Python binding to XML-RPC based API. After all these settings, we approach to make the system user friendly by making GUI of the main server. Using that GUI, user can perform administrative functions like restart, suspend or resume a virtual machine. They can also logon to the slave host of the pool in case of emergency and if needed, they can also filter virtual machine by the host. Network monitoring can be performed on multiple virtual machines at same time in order to detect any loss of network connectivity.