13,641 research outputs found

    Barrier inhomogeneities of Al/p-In2Te3 thin film Schottky diodes

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    The current-voltage (I-V) and capacitance-voltage (C-V) characteristics of p-In2Te3/Al thin films Schottky diodes papered by Flash Evaporation technique were measured in the temperature range 303-335 K have been interpreted on the basis of the assumption of a Gaussian distribution of barrier heights (φbo) due to barrier height inhomogeneities that prevail at the interface. It has been found that the occurrence of Gaussian distribution of BHs is responsible for the decrease of the apparent BH (φbo) and increase of the ideality factor (η). The inhomogeneities are considered to have a Gaussian distribution with a mean barrier height of (φbm) and standard deviation (σs) at zero-bias. Furthermore, the activation energy value (φb) at T = 0 and Richardson constant (A**) value was obtained as 0.587 eV and 3.09 Acm– 2 K– 1 by means of usual Richardson plots. Hence, it has been concluded that the temperature dependence of the I-V characteristics of p-In2Te3/Al Schottky Diodes can be successfully explained on the basis of TE mechanism with a Gaussian distribution of the BHs. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2790

    STABILITY STUDY: REGULATORY REQUIRENMENT

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    Stability is an essential factor of quality, safety and efficacy of a drug product. The objective of stability study is to determine the shelf life, the time period of storage at a specified condition within which the drug product still meets its established specifications. Stability study is of three types that is physical, chemical and microbial stability. Various factors like oxygen, water, temperature, pH, moisture, light and concentration affect the stability. Present work aims to represent the stability testing (ST) requirements of International Conference on Harmonization (ICH), different regulatory agencies like, World Health Organization (WHO), Association of South East Asian Nations (ASEAN) and European Agency for Evaluation of Medicinal and Health Products (EMEA) and difference of those agencies with respect to ICH guideline. Most of the stability requirements for WHO, ASEAN, and EMEA are similar to the ICH guideline, except for the parameters like selection of batches and storage conditions

    Separating the roles of electrons and holes in the organic magnetoresistance of aluminum tris(8-hydroxyquinoline) organic light emitting diodes

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    Copyright 2008 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This article appeared in Journal of Applied Physics 104, 083703 (2008) and may be found at

    All Recent Mars Landers Have Landed Downrange - Are Mars Atmosphere Models Mis-Predicting Density?

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    All recent Mars landers (Mars Pathfinder, the two Mars Exploration Rovers Spirit and Opportunity, and the Mars Phoenix Lander) have landed further downrange than their pre-entry predictions. Mars Pathfinder landed 27 km downrange of its prediction [1], Spirit and Opportunity landed 13.4 km and 14.9 km, respectively, downrange from their predictions [2], and Phoenix landed 21 km downrange from its prediction [3]. Reconstruction of their entries revealed a lower density profile than the best a priori atmospheric model predictions. Do these results suggest that there is a systemic issue in present Mars atmosphere models that predict a higher density than observed on landing day? Spirit Landing: The landing location for Spirit was 13.4 km downrange of the prediction as shown in Fig. 1. The navigation errors upon Mars arrival were very small [2]. As such, the entry interface conditions were not responsible for this downrange landing. Consequently, experiencing a lower density during the entry was the underlying cause. The reconstructed density profile that Spirit experienced is shown in Fig. 2, which is plotted as a fraction of the pre-entry baseline prediction that was used for all the entry, descent, and landing (EDL) design analyses. The reconstructed density is observed to be less dense throughout the descent reaching a maximum reduction of 15% at 21 km. This lower density corresponded to approximately a 1- low profile relative to the dispersions predicted. Nearly all the deceleration during the entry occurs within 10- 50 km. As such, prediction of density within this altitude band is most critical for entry flight dynamics analyses and design (e.g., aerodynamic and aerothermodynamic predictions, landing location, etc.)

    The Oxidation of Azo Dyes and Its Relation to Light Fading

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    The action of light on dyed fibres in air appears in many cases to involve an oxidation of the dye. The present work has been a preliminary to the fuller investigation of the photochemistry of azo dyes several series of simple monoazo dyes have been examined. A study of thermal oxidation in solution by common oxidising agents was followed by comparison with a series of measurements of relative light fastness in an attempt to elucidate the mechanism of the light fading process. The work has confirmed that oxidation of azo dyes in aqueous media, with several common reagents, e.g., ceric sulphate, potassium dichromate or hydrogen peroxide, disrupts the azo group and leads to the formation of a diazo compound and a quinone. subsequently, these further decompose to give, respectively, a phenol and nitrogen (in acid media); and phthalic acid. The reaction thus appears to be common to many types of oxidising agent, since previous workers have observed similar effects with, e.g., sodium hypochlorite, lead dioxide and ozone. An acceptor has been used to combine with the quinone formed and thus enable it to be identified without danger of its further oxidation. By boiling the acid solution after oxidising the dye a quantitative yield of nitrogen from the azo group is obtained, except when free amino groups are also present. This procedure could be used in quantitative analysis. An hypothesis is put forward suggesting that the initial step in such chemical oxidation is one of hydrolytic attack on the -C= N- bond of the dye, when it is present as the hydrazone and not the azo tautomer. In order to confirm or disprove the postulated hypothesis, several dyes containing nitro, chloro, methyl, methoxy or sulphonic and carboxylic acid groups in various positions in the phenyl nucleus in the following parent dyes, were prepared. The rates of oxidation of the water-soluble dyes in presence of various oxidising agents, such as neutral and alkaline hydrogen peroxide, potassium persulphate and dilute nitric acid were studied quantitatively. In the case of the insoluble dyes the rate of nitrogen evolution was examined as a measure of ease of oxidation. To correlate the oxidation of azo dyes with their relative light fastness, the above dyes were exposed in graded depths on substrates of wool, cellulose (cotton and filter paper), unglazed tile, and anodised aluminium. The last two materials were chosen in the hope they might he inert substrates. Fading and oxidation data were plotted against Hammett sigma values to determine the effect of substituents in the phenyl nucleus. The results appear to show that fading on wool is caused by hydrogen peroxide, which it is suggested may be produced by photolysis of the fibre itself, whereas on other substrates some other disruption process of the dye molecule occurs, perhaps by attack of atmospheric oxygen. The results also signify that the initial step in fading is a simple reaction involving attack at one of the unsaturated centres of the dye molecule

    Thermal Dissolution of Lignite Under Hydrogen Pressure

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    The hydrogenation-solution reaction of North Dakota lignite was studied with various organic solvents in a batch microautoclave at reaction conditions of 740 degrees F. and 1500 psig. initial hydrogen pressure. The solvents included aliphatic, aromatic, cycloparaffinic, heterocyclic, phenolic and amino compounds. The extent of dissolution was measured from the amount of residue retained on an asbestos filter-mat after it was washed and dried. It was found that the hydroaromatic compounds were very effective, giving more than 70 percent solubilization of lignite in solution reaction. Four lignites from different mines in the Northern Great Plains Provinces were dissolved in tetralin at the same operating conditions to study the effect of composition of lignite on the solution reaction. Lignites studied ranged from 71 percent to 82 percent solubilization. There was no evident correlation between the extent of solubilization and the proximate analysis. Also, the percent solubilization and the heating value of lignite did not show any correlation in the samples studied

    Line shifts in the first overtone of DF broadened by HF

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    Line spectra shifts in HF and in first overtone band of DF induced by HF pressure

    સુરેન્દ્રનગર જિલ્લાની શૈક્ષણિક સંસ્થાઓનુ સામાજિક પ્રદાન

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    શિક્ષણ સમાજના વિકાસનો પાયો છે. શિક્ષણ માનવીની આંતરિક શક્તિનો વિકાસ કરતું હોવાથી તથા તે માનવ ઘડતરની મુખ્ય સામાજિક ક્રિયા હોવાથી તેનું સ્થાન માનવજીવનમાં શ્રેષ્ઠ છે. શિક્ષણ શાસ્ત્રીઓ અને સમાજશાસ્ત્રીઓએ શાળાને સામાજિક વ્યવસ્થા તરીકે ઓળખાવી છે. શૈક્ષણિક સંસ્થાઓ વિદ્યાર્થીઓ અને તે થકી સમાજમાં જીવનવિકાસ માટેનું તાલીમ કેન્દ્ર છે. આ શૈક્ષણિક સંસ્થાઓ સમાજનાં વિકાસ માટે કયાં પ્રકારની શૈક્ષણિક પ્રવૃત્તિઓ કરે છે. અને તે દ્વારા કઈ કઈ સામજીક પ્રવૃત્તિઓ હાથ ધરે છે. આ પ્રવૃત્તિઓ હાથ ધરે છે. આ પ્રવૃત્તિઓ હાથ ધરે છે. આ પ્રવૃત્તિઓની તપાસ કરવાનો પ્રયાસ પ્રસ્તુત સંશોધનમાં કરવામાં આવ્યો હતો. શિક્ષણનો વ્યાપ ખૂબ જ વધી રહ્યો છે. તેમજ વિવિધ ક્ષેત્રોમાં વધતા-જતા પરિવર્તનોને કારણે શૈક્ષણિક સંસ્થાઓ, સમાજનાં વિકાસ માટે હજુ વધુ સામાજિક પ્રવૃત્તિઓ હાથ ધરી શકે તેમ છે. તેના માટેની યાદી તૈયાર કરવી જરૂરી જણાય છે. તેને ધ્યાનમાં લઈને સામાજિક પ્રવૃત્તિઓની યાદી અને વિગતો તૈયાર કરવાનો પ્રયત્ન કરવામાં આવ્યો હતો. આ સામાજિક પ્રવૃત્તિઓની યાદીમાંથી સમાજને વધુ ઉપયોગી થઈ શકે તેવી અને શૈક્ષણિક સંસ્થાઓ સરળતાથી યોજી શકે તેવી સામાજિક પ્રવૃત્તિઓને જુદી તારવવામાં આવી. તેને આવરી લેતાં સામાજિક કાર્યક્રમની સંરચના કરવામાં આવી અને રચાયેલા સામાજિક કાર્યક્રમની અસરકારકતા ચકાસવાનો પ્રયાસ પ્રસ્તુત સંશોધન દ્વારા હાથ ધરવામાં આવ્યો હતો

    Local anaesthetic adjuncts for peripheral nerve blockade.

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    Moderate-to-severe pain is common and remains a significant problem. Compared with opioid analgesia alone, single-shot peripheral nerve blockade has been associated with improved pain relief and the potential of decreased side effects. Single-shot nerve blockade, however, is limited by its relatively short duration of action. In this review, we aim to summarize the evidence related to local anaesthetic adjuncts for peripheral nerve blockade. Dexamethasone and dexmedetomidine exhibit characteristics that most closely resemble the ideal local anaesthetic adjunct. In upper limb block, dexamethasone has been demonstrated to be superior to dexmedetomidine regardless of administration route for the duration of sensory and motor blockade as well as the duration of analgesia. No clinically significant differences between intravenous and perineural dexamethasone were found. Perineural and intravenous dexamethasone have the potential to prolong sensory blockade to a greater extent than motor blockade. The evidence indicates that the mechanism of action of perineural dexamethasone in upper limb block is systemic in nature. Unlike perineural dexmedetomidine, intravenous dexmedetomidine has not been shown to result in differences in the characteristics of regional blockade compared with local anaesthetic alone. Intravenous dexamethasone is the local anaesthetic adjunct of choice, increasing the duration of sensory and motor blockade as well as the duration of analgesia by 477, 289 and 478 min, respectively. In view of this, we recommend consideration of the intravenous administration of dexamethasone at a dose of 0.1-0.2 mg/kg for all patients undergoing surgery whatever the level of postoperative pain, mild, moderate or severe. Further research should focus on the potential synergism of action between intravenous dexamethasone and perineural dexmedetomidine
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