Organic nonvolatile memory devices utilizing intrinsic charge-trapping phenomena in an n-type polymer semiconductor

Murari, N.M.,Hwang, Y.J.,Kim, F.S.,Jenekhe, S.A. Elsevier Science 2016 ORGANIC ELECTRONICS Vol.31 No.-

<P>Charge trapping is an undesirable phenomenon and a common challenge in the operation of n-channel organic field-effect transistors. Herein, we exploit charge trapping in an n-type semiconducting poly (naphthalene diimide-alt-biselenophene) (PNDIBS) as the key operational mechanism to develop high performance, nonvolatile, electronic memory devices. The PNDIBS-based field-effect transistor memory devices were programmed at 60 V and they showed excellent charge-trapping and de-trapping characteristics, which could be cycled more than 200 times with a current ratio of 10(3) between the two binary states. Programmed data could be retained for 10(3) s with a memory window of 28 V. This is a record performance for n-channel organic transistor with inherent charge-trapping capability without using external charge trapping agents. However, the memory device performance was greatly reduced, as expected, when the n-type polymer semiconductor was end-capped with phenyl groups to reduce the trap density. These results show that the trap density of n-type semiconducting polymers could be engineered to control the inherent charge-trapping capability and device performance for developing high-performance low-cost memory devices. (c) 2016 Elsevier B.V. All rights reserved.</P>

Effect of Impurity Location and Inter-Impurity Distance on Normal Mode Frequencies of a Finite Linear Chain under General Boundary Condition

Murari Sinha,Jin Seung Kim,Keum Hwi Lee 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.44 No.6

The dynamics of a nite linear chain with two impurities has been investigated to understand the dependence of the normal mode frequencies on the impurity locations and the inter-impurity distance on the basis of the analytic solution for a chain under general boundary conditions. The result shows that the location of a single impurity does cause a change in the normal mode frequencies, especially for higher-order modes and for locations near the node or anti-node positions. Also, the inter-impurity distance has the largest in uence when it is about one-third to one-half of the chain length.

Distribution of phonon frequencies in superconducting oxide spinel (Li,Mg)1+xTi2-xO4

Murari Mohan Sinha,Jin Seung Kim 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.43 No.2

The phonon densities of states of the spinel phases Li$_{1+x}$Ti$_{2-x}$O$_4$ ($x$ = 0, 0.33) and Li$_{1-y}$Mg$_y$Ti$_2$O$_4$ ($y$ = 0.1, 0.3) (space group Fd3m) have been calculated by applying the Blackman sampling method. The calculated results are compared with experimental data. The effect of Mg$^{2+}$ substitution for Li$^+$ in LiTi$_2$O$_4$ on the phonon density of states is also studied and discussed.

Analysis of vibrational modes and phonon density of states of aluminate spinels

Murari Sinha,Jin Seung Kim 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.43 No.2

The zone-center phonons of MgAl$_2$O$_4$ and ZnAl$_2$O$_4$ have been calculated by applying an angular force constant model. The justified Raman mode ($A_{1g}$) at 772 cm$^{-1}$ is taken into consideration for the calculation of the phonons in MgAl$_2$O$_4$. The effect of mass on the interatomic interaction and the vibrational modes in these aluminates is analyzed. The phonon density of states (PDOS) has been calculated in the aluminate spinels by using a sampling method. The effect of heavier Zn on the PDOS is prominent. Also, the lattice dynamics in Zn and Mg aluminate spinels are found to be similar. The calculated results are in good agreement with the experimental data.

Kinetic model for sorption of divalent heavy metal ions on low cost minerals

Murari Prasad,Aseem Chawla,Rishta Goswami,Shweta Ranshore,Ankita Kulshreshtha,Akhouri Sudhir Kumar Sinha 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.2

A mathematical model is proposed that could predict the kinetic parameters for adsorption of divalent heavy metal ions (lead, copper and zinc) onto low-cost adsorbents such as pyrophyllite and rock phosphate using experimental data. The experiments were conducted with the initial concentrations of metal ions ranging from 10mg/L to 100mg/L. The mathematical model is based on the application of the Redlich-Peterson isotherm to mass transfer across the film surrounding the adsorbent. The developed non-linear sorption kinetic (NSK) mathematical model was solved using numerical integration by the trapezoidal method in Microsoft Excel along with the SOLVER function to obtain the best simulated values of the Redlich-Peterson constants A, B, r, the order of reaction n, and the film transfer coefficient α. Dissolution followed by precipitation was found to be the most probable mechanism responsible for heavy metal ion uptake by rock phosphate, while for pyrophyllite physical adsorption was governing mechanism at low concentrations (<100mg/L). The values of parameters A, B, r and α lie in the ranges of 0.015-23.2, 0.00003-3.09, 0.072- 1, and 0.000057-52.8 [(L/mg)(n−1)/min], respectively, under different experimental conditions.

Unbiased and non-supervised learning methods for disruption prediction at JET

Murari, A.,Vega, J.,Rattá,, G.A.,Vagliasindi, G.,Johnson, M.F.,Hong, S.H. International Atomic Energy Agency 2009 Nuclear fusion Vol.49 No.5

<P>The importance of predicting the occurrence of disruptions is going to increase significantly in the next generation of tokamak devices. The expected energy content of ITER plasmas, for example, is such that disruptions could have a significant detrimental impact on various parts of the device, ranging from erosion of plasma facing components to structural damage. Early detection of disruptions is therefore needed with evermore increasing urgency. In this paper, the results of a series of methods to predict disruptions at JET are reported. The main objective of the investigation consists of trying to determine how early before a disruption it is possible to perform acceptable predictions on the basis of the raw data, keeping to a minimum the number of ‘ad hoc’ hypotheses. Therefore, the chosen learning techniques have the common characteristic of requiring a minimum number of assumptions. Classification and Regression Trees (CART) is a supervised but, on the other hand, a completely unbiased and nonlinear method, since it simply constructs the best classification tree by working directly on the input data. A series of unsupervised techniques, mainly K-means and hierarchical, have also been tested, to investigate to what extent they can autonomously distinguish between disruptive and non-disruptive groups of discharges. All these independent methods indicate that, in general, prediction with a success rate above 80% can be achieved not earlier than 180 ms before the disruption. The agreement between various completely independent methods increases the confidence in the results, which are also confirmed by a visual inspection of the data performed with pseudo Grand Tour algorithms.</P>

Enhanced Removal of Phenol from Aquatic Solution in a Schorl-catalyzed Fenton-like System by Acid-modified Schorl

Huan-Yan Xu,Murari Prasad,Peng Wang 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.4

Schorl modified by H₂SO4 has been successfully developed to enhance schorl-catalyzed Fenton-like reaction for removal of phenol in an aqueous solution. The phenol removal percentage can be increased from 4% to 100% by the system of modified schorl and H₂O₂. Batch experiments indicate that the percent increases in removal of phenol by increasing the dosage of catalyst, temperature and initial concentration of H₂O₂. The results of XRD, FT-IR and SEM suggest that no new phases are formed after removal of phenol by modified schorl. ICP-AES results reveal that more dissolution of iron results in higher catalytic oxidant activity in the system of modified schorl and H₂O₂. Besides minor adsorption, mineralcatalyzed Fenton-like reaction governs the process.

Enhanced Removal of Phenol from Aquatic Solution in a Schorl-catalyzed Fenton-like System by Acid-modified Schorl

Xu, Huan-Yan,Prasad, Murari,Wang, Peng Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.4

Schorl modified by $H_2SO_4$ has been successfully developed to enhance schorl-catalyzed Fenton-like reaction for removal of phenol in an aqueous solution. The phenol removal percentage can be increased from 4% to 100% by the system of modified schorl and $H_2O_2$. Batch experiments indicate that the percent increases in removal of phenol by increasing the dosage of catalyst, temperature and initial concentration of $H_2O_2$. The results of XRD, FT-IR and SEM suggest that no new phases are formed after removal of phenol by modified schorl. ICP-AES results reveal that more dissolution of iron results in higher catalytic oxidant activity in the system of modified schorl and $H_2O_2$. Besides minor adsorption, mineral-catalyzed Fenton-like reaction governs the process.

Fluorescence spectroscopic study to characterize and monitor TEOS based sol-gel process for development of optical biosensors

N.K.Chaudhury,R.Bhardwaj,B.M.Murari 한국물리학회 2003 Current Applied Physics Vol.3 No.2, 3

Development of optical biosensors is an active area of research in the field of medical technology. Solgel matrices made fromalkoxide silicates,tetraethyl orthosilicate (TEOS) appear to be suitable glassy host matrix for the sensing system. However,themajor problem in the TEOS based solgel matrices is stability. So it is important to study dopantmatrix interaction as a function of time. In the present study,we report uorescence emission and excited state lifetime measurements on uorescent probes entrappedin TEOS solgel for monitoring the physico-chemical processes for characterization and monitoring of local environment (pores) ofviz.,Hoechst 33258 (H258) and pyranine (PY) were used. Solgels containing these probes were prepared at pH¼ 6:0 and thephysical and spectroscopic parameters were monitored as a function of storage time (days). The emission intensity from entrappedH258 has shown relatively higher extent of decrease during aging. The excited state uorescence lifetime measurements on theseprobes depicted single exponential decay component at 5.4 ns (PY) and 3.6 ns (H258) in fresh solgels. After a few days of storageprobe molecule PY. Further conrmation of multicomponents decay was obtained by distribution analysis of lifetime of H258where an increase in width of mean lifetime was observed with storage whereas no such change was indicated from PY. Thus itappears that H258 is a better probe molecule for characterizing and monitoring local environment of pores in solgel.. 2002 Elsevier Science B.V. All rights reserved.

Effect of Sources of Supplementary Protein on Intake, Digestion and Efficiency of Energy Utilization in Buffaloes Fed Wheat Straw Based Diets

Mehra, U.R.,Khan, M.Y.,Lal, Murari,Hasan, Q.Z.,Das, Asit,Bhar, R.,Verma, A.K.,Dass, R.S.,Singh, P. Asian Australasian Association of Animal Productio 2006 Animal Bioscience Vol.19 No.5

Sixteen adult male buffaloes (average body weight $443{\pm}14kg$) were equally distributed into four groups in an experiment to study the effect of supplementary protein sources on energy utilization efficiency in buffaloes fed a wheat straw-based diet. The animals in the control group were offered a basal diet composed of 700 g deoiled ground nut cake and ad libitum wheat straw. Animals of other groups were offered 1.8 kg of soyabean meal (SBM), linseed meal (LSM) or mustard cake (MC) along with the basal diet. Protein supplementation increased the digestibility of DM (p<0.01), OM (p<0.01) CP (p<0.01) and CF (p<0.05). Maximum CP digestibility was observed on SBM, followed by LSM and MC when compared to the control. Total DMI and DOMI was significantly (p<0.01) higher in protein supplemented groups with no differences between treatment groups. Digestible crude protein (DCP) intake and N balance were significantly (p<0.01) different between the groups; maximum response was obtained with SBM supplementation, followed by LSM and MC. Faecal energy was significantly (p<0.01) lower in SBM and LSM groups in comparison to other groups. Methane production (% DEI) was significantly (p<0.05) lower on the SBM treatment. Metabolizable energy (ME) intake increased significantly due to protein supplementation. Metabolizable energy intake (MEI) of animals in the MC group was less than LSM and SBM. Energy balance was increased significantly (p<0.01) due to protein supplementation and within supplement variation was also significant with maximum balance in SBM followed by LSM and MC groups. Protein supplementation significantly (p<0.05) increased the digestibility and metabolizability of energy from whole ration. Metabolizable energy (ME) content (Mcal/kg DM) of SBM, LSM and MC was 4.49, 3.56 and 2.56, respectively. It was concluded that protein supplementation of wheat straw increased intake, digestibility and metabolizability of energy and maximum response could be obtained when soybean meal was used as a supplement.