Synthesis, Structure and Characterization of Nd_2XCd_2-3XSiO₄ (0.01≤X≤0.21) Solid-Solutions

Ramesh, S.,Das, B.B. Korean Chemical Society 2011 대한화학회지 Vol.55 No.3

[ $Nd_{2x}Cd_{2-3x}SiO_4$ ]($0.01{\leq}x{\leq}0.21$) [S1-S3: x=0.01, 0.11 and 0.21] 고용체를 졸-겔 방법을 통해 합성하였다. X선 분말회절(XRD) 측정은 $P2_1$/m 공간군의 단사정계를 보여준다. 평균 결정 크기는 20-45 nm이다. 주사전자현미경(SEM)으로 살펴본 모양은 구형의 특성을 보인다. 에너지 분산 X 선 분광기(EDS) 결과로부터 모든 구성 원소의 존재를 확인하였다. ~750 nm에서의 흡수 밴드는 $Nd^{3+}$ 이온의 $^4I_{9/2}{\rightarrow}^4F_{7/2}+^4S_{3/2}$ 전이에 기인한다. 10, 40, 77, 300 K에서 S1-S3의 전자 상자성 공명 (EPR) 선모양은 $Nd^{3+}$ 이온의 빠른 스핀 격자 이완에 기인하는 폭이 넓은 구분되지 않은 등방성의 선모양을 보여준다. Synthesis of $Nd_{2x}Cd_{2-3x}SiO_4$ ($0.01{\leq}x{\leq}0.21$) [S1-S3: x=0.01, 0.11 and 0.21] solid solutions were prepared by solgel method. Powder x-ray diffraction (XRD) results show monoclinic unit cell with space group P21/m. The average crystallite sizes are found to be 20 to 45 nm. The Scanning Electron Microcopy (SEM) images show morphology of the sample is in globular nature. The energy dispersive analysis of x-rays (EDX) and X-ray mapping results confirmed that all the constituent elements of the composites were present and that were distributed in uniformly. The optical absorption band at ~750 nm was due to $^4I_{9/2}{\rightarrow}^4F_{7/2}+^4S_{3/2}$ transition optically active $Nd^{3+}$ ions. Electron Paramagnetic Resonance (EPR) lineshapes of S1-S3 at 10, 40, 77 and 300 K show a broad unresolved isotropic lineshapes were observed due to rapid spin lattice relaxation of $Nd^{3+}$.

Implications of Five Laws of Library Science on Dr. S R Ranganathan’s Colon Classification: An Explorative Study

S. K Asok Kumar,B. Ramesh Babu,P. Nageswara Rao 한국문헌정보학회 2011 한국문헌정보학회지 Vol.45 No.4

There have been several milestones in the history of library classification but most of the schemes failed to meet the new challenges in the organisation of information. Dr S R Ranganathan tried to revolutionise the whole thinking on classificatory approach, when he devised the Colon Classification (CC) in 1933. He developed the Colon Classification scheme with a sound theoretical background based on normative principles, Five laws of Library science, canons, etc. One important feature of CC is that, its use is not confined to information storage and retrieval alone. This paper presents an over view of different editions of the CC highlighting the salient features of the editions. Further the implication of Five Laws of Library Science has been described. The authors stressed that the features of such as greater hospitality, specificity and mixed notation has paved the way to design and develop the depth schedules on various micro level subjects and so far about 130 micro schedules have been published. The impressions by the leading LIS professionals during and after Ranganathan’s time have been highlighted. The authors expressed the fear that when the library world would see the complete version of the seventh edition of CC? It may be due to lack of institutional support engaging in the research or financial constraints. The authors are of the opinion that any scheme to flourish needs a sound research body to bring out the revised editions as done in the case of Dewey Decimal Classification. The relevance of the CC in the contemporary world of Librarianship is discussed. Finally concludes that CC needs to be resuscitated as it is a precious national heritage; and still a force for the management of libraries.

Effect of fermented Panax ginseng extract (GINST) on oxidative stress and antioxidant activities in major organs of aged rats

Ramesh, T.,Kim, S.W.,Sung, J.H.,Hwang, S.Y.,Sohn, S.H.,Yoo, S.K.,Kim, S.K. Pergamon Press ; Elsevier Science Ltd 2012 Experimental Gerontology Vol.47 No.1

The intracellular levels of oxidant and antioxidant balances are gradually distorted during the aging process. An age associated elevation of oxidative stress occurring throughout the lifetime is hypothesized to be the major cause of aging. The present study was undertaken to evaluate the putative antioxidant activity of the fermented Panax ginseng extract (GINST) on lipid peroxidation and antioxidant status of major organs of aged rats compared to young rats. Increased levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea and creatinine were observed in the serum of aged rats. Increased levels of malondialdehyde (MDA) and significantly lowered activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST) were observed in the liver, kidneys, heart and lungs of aged rats, when compared with those in young rats. Quantitative analysis of the non-enzymatic antioxidants such as reduced glutathione (GSH), ascorbic acid and α-tocopherol levels showed significantly lower values in the liver, kidneys, heart and lungs of aged rats. On the other hand, administration of the fermented Panax ginseng extract (GINST) to aged rats resulted in increased activities of SOD, CAT, GPx, GR and GST as well as elevation in GSH, ascorbic acid and α-tocopherol levels. Besides, the level of MDA, AST, ALT, urea and creatinine were reduced on administration of GINST to aged rats. These results suggested that treatment of GINST can improve the antioxidant status during aging, thereby minimizing the oxidative stress and occurrence of age-related disorders associated with free radicals.

Cordycepin (3'-deoxyadenosine) attenuates age-related oxidative stress and ameliorates antioxidant capacity in rats

Ramesh, T.,Yoo, S.K.,Kim, S.W.,Hwang, S.Y.,Sohn, S.H.,Kim, I.W.,Kim, S.K. Pergamon Press ; Elsevier Science Ltd 2012 Experimental Gerontology Vol.47 No.12

Free radical-induced oxidative damage is considered to be the most important consequence of the aging process. The activities and capacities of antioxidant systems of cells decline with increased age, leading to the gradual loss of pro-oxidant/antioxidant balance and resulting in increased oxidative stress. Our investigation was focused on the effects of cordycepin (3'-deoxyadenosine) on lipid peroxidation and antioxidation in aged rats. Age-associated decline in the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione-S-transferase (GST), reduced glutathione (GSH), vitamin C and vitamin E, and elevated levels of malondialdehyde (MDA) were observed in the liver, kidneys, heart and lungs of aged rats, when compared to young rats. Furthermore, serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea, and creatinine were found to be significantly elevated in aged rats compared to young rats. Aged rats receiving cordycepin treatment show increased activity of SOD, CAT, GPx, GR and GST, and elevated levels of GSH, and vitamins C and E such that the values of most of these parameters did not differ significantly from those found in young rats. In addition, the levels of MDA, AST, ALT, urea and creatinine became reduced upon administration of cordycepin to aged rats. These results suggest that cordycepin is effective for restoring antioxidant status and decreasing lipid peroxidation in aged rats.

Thymic Hassall's corpuscles in Nandanam chicken - light and electronmicroscopic perspective (Gallus domesticus)

Kannan, Thandavan Arthanari,Ramesh, Geetha,Ushakumary, S.,Dhinakarraj, Gopalan,Vairamuthu, Subbiah Korean Society of Animal Science and Technology 2015 한국축산학회지 Vol.57 No.10

The present study was aimed to study the light and electron microscopic studies of thymic Hassall's corpuscles was done in various age groups of Nandanam Chicken ranging from day-old to forty weeks. Hassall's corpuscles are special, unique structures present in thymic medulla and also in the cortex of all the age groups of Nandanam chicken (from hatch to forty weeks) in the present study. Size of the Hassall's corpuscles in the medulla is larger than the ones present in the cortical region of thymus. The Hassall's corpuscles are made up of structureless eosinophilic mass surrounded by concentrically arranged reticuloepithelial cells. Under electron microscope, the Hassall's corpuscles were composed of reticuloepithelial cells interconnected by many desmosomes. The epithelial cells had abundance of cytoplasmic fibrils and desmosomes with few mitochondria and ribosomes. The nucleus was oval or round which was slightly indented. The centre of the Hassall's corpuscles was appeared either solid or cystic. The cystic corpuscles had cell debris within the cyst lumen.

Open Access : Thymic Hassall`s corpuscles in Nandanam chicken - Light and electronmicroscopic perspective (Gallus domesticus)

( Thandavan Arthanari Kannan ),( Geetha Ramesh ),( S. Ushakumary ),( Gopalan Dhinakarraj ),( Subbiah Vairamuthu ) 한국동물자원과학회(구 한국축산학회) 2015 한국축산학회지 Vol.57 No.30

The present study was aimed to study the light and electron microscopic studies of thymic Hassall``s corpuscles was done in various age groups of Nandanam Chicken ranging from day-old to forty weeks. Hassall``s corpuscles are special, unique structures present in thymic medulla and also in the cortex of all the age groups of Nandanam chicken (from hatch to forty weeks) in the present study. Size of the Hassall``s corpuscles in the medulla is larger than the ones present in the cortical region of thymus. The Hassall``s corpuscles are made up of structureless eosinophilic mass surrounded by concentrically arranged reticuloepithelial cells. Under electron microscope, the Hassall``s corpuscles were composed of reticuloepithelial cells interconnected by many desmosomes. The epithelial cells had abundance of cytoplasmic fibrils and desmosomes with few mitochondria and ribosomes. The nucleus was oval or round which was slightly indented. The centre of the Hassall``s corpuscles was appeared either solid or cystic. The cystic corpuscles had cell debris within the cyst lumen.

Synergistic effect of reduced graphene oxide, CNT and metal oxides on cellulose matrix for supercapacitor applications

Ramesh, S.,Khandelwal, Saurabh,Rhee, Kyong Yop,Hui, David Elsevier 2018 Composites Part B, Engineering Vol.138 No.-

<P><B>Abstract</B></P> <P>In this paper, a hybrid nanocomposite of cellulose fiber/multi-walled carbon nanotube (MWCNT)/reduced graphene oxide (rGO)/Cobalt oxide (Co<SUB>3</SUB>O<SUB>4</SUB>)/tin oxide (SnO<SUB>2</SUB>) is synthesized via a hydrothermal method for supercapacitor applications and characterized for their electrochemical performance and thermal stability. The morphology of the nanocomposites was characterized by using scanning electron microscope (SEM) and transmission electron microscope (TEM). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Raman spectroscopy were used to determine the chemical groups and crystal structure. Energy dispersive X-ray spectroscopy (EDX) confirmed the constitutional proportions of various elements in the composite. The electrode was fabricated from the nanocomposite and characterized by cyclic voltammetry (CV) that showed good cyclic stability with 88% capacitance retention after 1000 cycles and a capacitance of 215 F g<SUP>−1</SUP> and 181 F g<SUP>−1</SUP>at a current density of 0.2 A g<SUP>−1</SUP>and 0.4 A g<SUP>−1</SUP>, respectively. The hybrid nanocomposite showed higher thermal stability than cellulose fiber/MWCNT and cellulose fiber/MWCNT/rGO composites. This simple, scalable and low-cost approach could open new opportunities for next-generation energy storage devices.</P>

Design of nanocapacitors and associated materials challenges

S. Ramesh Ekanayake,Michael J. Ford,Michael B. Cortie 한국물리학회 2004 Current Applied Physics Vol.4 No.2-4

The International Technology Roadmap for Semiconductors (ITRS) projects that the spatial resolution of feature sizes inintegrated circuits is rapidly approaching nanoscopic dimensions. Consequently, there is an active interest in the design of nanoscalecircuit elements such as transistors, resistors, andcapacitors. The properties of materials used to fabricate capacitors pose animportant design factor, as with all circuit elements. We analyze the critical materials properties that would inuence engineeringnanocapacitors (nanoscopic capacitors), and show that at nanoscale, dielectric properties (dielectric constant, dielectric strength,and dielectric relaxation) determine the practicality of such capacitors.

Structural studies of a green-emitting terbium doped calcium zinc phosphate phosphor

Ramesh, B.,Dillip, G.R.,Rambabu, B.,Joo, S.W.,Raju, B. Deva Prasad Elsevier 2018 Journal of molecular structure Vol.1155 No.-

<P><B>Abstract</B></P> <P>In this study, a new green emitting CaZn<SUB>2</SUB>(PO<SUB>4</SUB>)<SUB>2</SUB>:Tb<SUP>3+</SUP> phosphors were synthesized through solid-state reaction route. The phosphors were characterized structurally by X-ray diffraction, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). All the synthesized phosphors were crystallized in triclinic crystal structure with <I>P</I> 1 ¯ space group. The phosphate groups in the phosphors were confirmed by FTIR analysis. The surface elements O <I>1</I>s, P <I>2</I>p, Ca <I>2</I>p, Zn <I>2</I>p and Tb 3<I>d</I> were studied by high-resolution XPS spectra. Upon excitation at 378 nm, the dominant green emission of CaZn<SUB>2</SUB>(PO<SUB>4</SUB>)<SUB>2</SUB>:Tb<SUP>3+</SUP> phosphors at 542 nm were noticed in the emission spectra. For various emission wavelengths (at 435 and 489 nm) and constant excitation wavelength (at 378 nm), the decay curves have shown two different decay dynamics of phosphors. The lighting properties such as Commission International de l’Eclairage (<I>x</I> = 0.319, <I>y</I> = 0.398) and color temperature (5995 K) were calculated.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A green emitting CaZn<SUB>2</SUB>(PO<SUB>4</SUB>)<SUB>2</SUB>:Tb<SUP>3+</SUP> phosphors were synthesized. </LI> <LI> Chemical bonds of PO, CaO, ZnO and TbO were investigated by XPS. </LI> <LI> The phosphor has two different decay dynamics upon various emissions. </LI> <LI> Chromaticity coordinates were located in green region of visible spectrum. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Detection of Defects on Steel Surface for using Image Segmentation Techniques

S. M. Ramesh,B. Gomathy,T.V.P.Sundararajan 보안공학연구지원센터 2014 International Journal of Signal Processing, Image Vol.7 No.5

An online surface inspection system m of hot rolled strips is introduced. This system is designed t o detect such main Surface defects on hot rolled strips as scar, scratches, pits, water drops Cracks. Cross hatchings, and so on. Multiple CCD area scan cameras are adopted to capture images of strip surface simultaneously, and all the images are processed by parallel computation system Real-time, which is supported by fast image process techniques and parallel computation techniques, in order to snap main defect regions on the surface of strips. At last, the defects will be classified to several types. The application of the system to practical production line shows that it can detect main defects of hot rolled strips more effectively than traditional method, and it is easily to be maintained.