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In the presented study, the performance improvement of Au/PTCDA/n-Si diodes was demonstrated with the help of pre-irradiation of PTCDA powders. The crystallographic analysis was carried out by X-ray diffraction method after the pre-irradiation of PTCDA powders. After the vacuum deposition of pre-irradiated (PI) and unirradiated (UI) PTCDA thin films, the Au/PTCDA/n-Si diodes were fabricated. The I-V, C-V, and G/omega-V characteristics were analyzed for Au/PTCDA/n-Si diodes with UI PTCDA as an interfacial layer (D1-pristine) and PI PTCDA with 30 kGy as an interfacial layer (D2). Radiation-induced effects on the produced diodes were investigated with parameters of the barrier height (phi(Bo)), series resistance (R-s), and the density of interface states (N-SS) and compared to the parameters of the pristine diode. It was observed that the electrical characteristics of Au/PTCDA/n-Si diodes, for D1 and D2, were highly influenced by the irradiation. Thus, the device performance could be improved with the pre-irradiation process. By modifying the HF-LF capacitance method to the UI-PI capacitance method, we successfully calculated the radiation-induced N-SS values without using C-V measurement at two different frequencies.

The main concern of the present study is to improve the performance of Au/Alq3/n-Si diode with the help of a high-energy electron beam (e-Beam) irradiation. Before the production of Au/Alq3/n-Si, the structural analysis was carried out by X-Ray diffraction (XRD) to ensure that the radiation-induced structural deformation does not occur on the Alq3 powders. After vacuum deposition of Alq3 thin films, Fourier transfrom infrared (FTIR) measurements were also carried out. The current-voltage characteristics of Au/Alq3/n-Si diodes with Alq3 interfacial layer unirradiated (D1-pristine) and irradiated with 30 kGy (D2) and 100 kGy (D3) were discussed in detail. To analyze the effect of ionizing radiation on the produced diodes, we calculated the barrier height (ΦBo), ideality factor (n), shunt resistance (Rsh), and series resistance (Rs) by using these experimental data. It was observed that the electrical characteristics of Au/Alq3/n-Si diodes, for D1, D2, and D3, were highly influenced by the irradiation, and the device performance could be improved with the appropriate irradiation dose. Moreover, we achieved the series resistance tuning of Au/Alq3/n-Si diodes by irradiating Alq3 powders with high-energy e-Beam without intentional chemical doping of organic interfacial layer as a novel. This study has the potential to be a helpful guide for researchers who design and perform analysis of such devices.

In this study, the surface plasmon resonance-based fiber optic sensor using two-dimensional (2D) TMDC materials covering the Au/Ag bimetallic layer has been reported. Since MoS2, MoSe2, WS2, and WSe2 are the most popular ones, they are constructed as the resonant layer of the sensor. The layer-dependencies and heterostructures of the TMDC materials are examined for the determination of their effect on the performance of the SPR sensor. The performance parameters of the SPR sensor, the sensitivity, accuracy, and figure of merit, are calculated with the help of the MATLAB simulations. It is found out that considering the very small change in the refractive index of the sensing medium (0.0025), the monolayer MoSe2 has the highest sensitivity value of 8096 nm/RIU. In contrast, the monolayer WS2 has the highest accuracy and figure of merit values of 0.34 and 136.89 RIU−1, respectively. This study will be benefited for a better understanding of the performance of the SPR based fiber optic sensor depending on the number of layers of TMDC materials and based on their heterostructures.

A novel structure with a fungus-shaped center embossed diaphragm (FCED) geometry has been proposed to modify in diaphragm-based Fabry-Perot fiber optic pressure sensors (FP-FOPS). The proposed FCED geometry was obtained by adding a pillar between the mesa and diaphragm. Before the simulation analysis of FCED, we derived mathematical equations of attenuation factor widening the acceptance radius. The attenuation factor is defined to understand sensor loss, which is neglected in the literature. With this derived formula, the light reflected from the deflected diaphragm and the light unguided in the fiber was detected. Since the deformation angle is zeroized in the FCED structures, the sensor loss due to the attenuation factor is eliminated. All the incident light being re-guided in the fiber. With FCED design’s help, the decreasing sensitivity in the center embossed diaphragms (CED) has been prevented. Moreover, the deviation of the frequency response of FCED remains lower than 1% compared with the results of conventional diaphragms. As a result, it produces a more stable sensor, and the FCED structure is less affected by manufacturing errors. The researchers can benefit from the use of our presented results when designing and producing new diaphragm-based FP-FOPS.

WOS: 000462481700004 The diaphragm-based sensor tip, which has a critical design in Fabry-Perot fiber optic acoustic sensor production, directly affects device performance. Fabry-Perot fiber optic acoustic sensors tip designs and investigations on different geometric dimensions and different diaphragm materials continue in the literature. In this study, it is predicted that graphene-like two-dimensional In2Se3 single crystal can be used for the diaphragm material which we report for the first time in the literature. Analytical calculations and numerical simulations have been carried out in order to use two-dimensional In2Se3 single crystals as diaphragm material for Fabry-Perot fiber optic acoustic sensors tip production. The calculation results of the Fabry-Perot fiber optic acoustic sensors tip we designed using In2Se3 single crystal are compared with conventional sensor tip made from Si, SiO2 and graphene as a diaphragm in the literature. Since In2Se3 crystal has a high refraction index, sensor visibility allows for long Fabry-Perot cavities, which creates alternative solutions where very short Fabry-Perot cavities are not possible. Another advantage of this feature is that the inner surface of the diaphragm does not need to be coated with reflective materials like gold, silver etc. Using the high density of In2Se3 crystals for diaphragm materials results in reducing the percentage of frequency in transitions from less dense to more dense environments. According to the simulation results, it is seen that it has high sensitivity of 64.12 nm/kPa and this is the result of having a low Young's modulus than other diaphragm materials like Si, SiO2, graphene of the same geometry reported in the literature. The calculation results were also obtained for other materials as 26.54 nm/kPa, 62.58 nm/kPa, and 4.57 nm/kPa for Si, SiO2 and graphene, respectively. The innovative diaphragm design proposed in this work for Fabry-Perot fiber optic acoustic sensors tip production has been advised alternative solutions when sensor sensitivity and visibility must be considered. Research Fund of the Erciyes UniversityErciyes University [FDK-2016-6811, FDK-2016-6815] This work was supported by the Research Fund of the Erciyes University. Project numbers FDK-2016-6811 and FDK-2016-6815. The authors would like to thank Erciyes University Clinical Engineering Research and Application Center for their support in the research activities among the staffs.

SUMMARY This paper makes the first attempt of extending implicit AUSM-family schemes to multiphase flow simulations. Water faucet, air–water shock tube and oscillating manometer problems are used as benchmark tests with the generic four-equation two-fluid model. For solving the equations implicitly, Newton's method along with a sparse matrix solver (UMFPACK solver) is employed, and the numerical Jacobian matrix is calculated. Comparison between implicit and explicit AUSM-family schemes is presented, indicating that similarly accurate results are obtained with both schemes. Furthermore, the water faucet problem is solved using both staggered and collocated grids. This investigation helps integrate high-resolution schemes into staggered-grid-based computational algorithms. The influence of the interface pressure correction on the simulation results is also examined. Results show that the interfacial pressure correction introduces numerical dissipation. However, this dissipation cannot eliminate the overshoots because of the incompatibility of numerical discretization of the conservative and non-conservative terms in the governing equations. The comparison of CPU time between implicit and explicit schemes is also studied, indicating that the implicit scheme is capable of improving the computational efficiency over its explicit counterpart. Copyright © 2014 John Wiley & Sons, Ltd.

In order to obtain the detailed information on the conduction mechanisms of the Au/n-GaAs Schottky barrier diode (SBD), the current-voltage (I-V) characteristics were carried out in the temperature range of 80-340 K by the steps of 20 K. The ideality factor (n) decreases, while the effective barrier height (Phi(Bo)) increases with increasing temperature (80-340 K). The semilogarithmic I-V curve is almost parallel for each temperature. Therefore, its slope and tunneling parameter (E-oo) remained almost constant as independent of temperature with an average of 27.47 V-1 and 28.04 meV, respectively. Furthermore, the reverse saturation current (I-s) ranges, indication that the charge transport mechanism in the Au/n-GaAs SBD is tunneling due to the weak temperature dependence of the I-s. Thus, it can be said that the experimental I-V data quite well obey the thermionic field emission (TFE) model especially at low temperatures rather than the other transport mechanisms. On the other hand, an abnormal decrease in the Phi(Bo) and increase in the n with decreasing temperature have been observed which leads to non-linearity in the activation energy plots and a linear relationship between the barrier heights (BHs) and the ideality factors of the SBD. The high value of n especially at low temperatures cannot be also explained only TFE theory. Therefore, we tried to explain the non-ideal behavior of the forward-bias I-V characteristics in Au/n-GaAs SBD with the basis of a thermionic emission (TE) mechanism with a Gaussian distribution (GD) of the BHs. The obtained results show that the temperature dependence of forward bias I-V characteristics of the Au/n-GaAs SBD can be successfully explained in terms of the TE mechanism with a double GD of BHs for low bias region (LBR) and moderate bias region (MBR). (C) 2013 Elsevier B.V. All rights reserved.

It is well known that the one-dimensional equations of motion for two-phase flow are non-hyperbolic. Non-hyperbolicity can lead to numerical instabilities, destroying the solution. However, researchers in the last few decades were able to show that inclusion of virtual mass and/or phase-to-interface pressure differences in the momentum equations successfully render the equations of motion hyperbolic. In the present paper, the effect of including virtual mass and phase-to-interface pressure terms in the momentum equations on the hyperbolicity of the two-phase model in the CATHENA 4 code is discussed. The study is motivated by the fact that the inclusion of either model has been shown in the open literature to lead to a hyperbolic system separately. However, no known study exists that examine hyperbolicity in the presence of both these terms in the momentum equations. In this work, both terms are considered in the model equations simultaneously and their implications on the hyperbolicity of the two-phase model are discussed. Specifically, it is shown that in the case of mixed flow, there is a distinct region of non-hyperbolicity that developers need to be aware of when their equations include both the virtual mass and the phase-to-interface terms. Selecting the coefficients of phase-to-interface pressure difference terms properly ensures that the equations are hyperbolic for a wide range of conditions.

The forward and reverse bias currentevoltage (I-V), capacitance-voltage (C-V) and conductance-voltage (G/omega-V) characteristics of the Au/PVA (Bi-doped)/n-Si Schottky barrier diodes (SBDs) have been investigated at room temperature by taking the interface states (N-ss) and series resistance (R-s) effects into account. The voltage dependent profiles of resistance (R-i) were obtained from both the I-V and C/G-V measurements by using Ohm's Law and Nicollian methods. The obtained values of R-i with agreement each other especially at sufficiently high bias voltages which correspond the value of R-s of the diode. Therefore, the energy density distribution profile of N-ss was obtained from the forward bias I-V data taking the bias dependence of the effective barrier height (BH) Phi(e) and R-s into account. The high value of ideality factor (n) was attributed to high density of N-ss and interfacial polymer layer at metal/semiconductor (M/S) interface. In order to examine the frequency dependence of some of the electrical parameters such as doping donor concentration (N-D), Phi(e), R-s and N-ss values, C-V and G/omega-V measurements of the diode were performed at room temperature in the frequency range of 50 kHz-5 MHz. Experimental results confirmed that the N-ss, R-s and interfacial layer are important parameters that influence electrical characteristics of SBD. (C) 2011 Elsevier B. V. All rights reserved.

Ge homojunctions were deposited by means of Metal Organic Vapour Phase Epitaxy (MOVPE) on Ge substrates at 550 degrees C and 675 degrees C, using AsH3 as n-type dopant. Ge-n/Ge-p, GaAsn/InGaPn/Ge-n/Ge-p and Ge-n/Ge-p/Ge-p structures were prepared and studied, where n and p identify the layer or substrate doping. Vertical mesa junctions were obtained on the above structures by using conventional photolithographic and evaporation techniques. The junctions were characterized by I-V measurements under dark and illumination conditions and by EBIC technique. It has been observed that the samples grown at lower temperature showed better rectifying I-V characteristics and light conversion efficiency while EBIC results may suggest that a high As diffusion is present in the samples grown at higher temperature. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

TiO2 thin films were deposited on polycrystalline n-type Si substrate using DC magnetron sputtering system. To improve the crystal quality, thermal annealing (TA) process was done at 700 degrees C and 900 degrees C. The effect of TA on the structural properties was investigated using high resolution X-ray diffraction (HRXRD). It was observed that the phase transition from amorphous phase to anatase and rutile phases occurs at 700 degrees C and 900 degrees C, respectively. Au/TiO2/n-Si structures were also fabricated for the investigation of TA on the main electrical parameters, such as ideality factor (n), barrier height (Phi B), series resistance (R-s), shunt resistance (R-sh) and interface states (N-ss). The current-voltage (I-V) and capacitance-voltage (C-V) characteristics have been investigated at room temperature and results have been compared with each other. The electrical characteristics showed that TA strongly affects the main electrical parameters. The rectifying ratio of Au/n-Si structures with anatase phase TiO2 was to be 140 while the rutile phase was to be 8864. The leakage current was also found to be very sensitive to the annealing temperature, and also the magnitude of the leakage current for rutile phase is 15 times lower than the anatase phase's. In addition, the energy distribution profile of N-ss of the structures was obtained from the forward bias I-V data by taking the bias dependence of the effective barrier height (Phi(e)) into account. For both of the samples, the value of N-ss decreases with TA. Similarly, the values of R-s and R-sh of the structures obtained from the forward bias I-V data were found as 209 Omega and 42 k Omega for the anatase and 59 Omega and 598 k Omega for the rutile phase. These results show that the performance of the Au/TiO2/n-Si structure improved with thermal annealing. (C) 2010 Elsevier B.V. All rights reserved.

The successive ionic layer adsorption and reaction (SILAR) method has been used to grow epitaxial CdS-polymer nanostructures as thin films with different surface morphology and particle size. The main purpose of the study was to investigate the dielectric properties and a.c. electrical conductivity (σ a.c.), by a.c. impedance spectroscopy between 1 kHz and 1 MHz, at room temperature, of CdS-polymer nanocomposites produced by use of 2, 6, and 10 cycles of SILAR. The surface morphology and optical absorption of the samples were characterized by scanning electron microscopy (SEM) and UV-visible spectroscopy, respectively. Determination of the energy gaps of CdS-polymer nanocomposites prepared by use of different numbers of cycles of SILAR reveals that the band gap decreases with increasing number of cycles (J. Cryst. Growth 305, 175-180, 2007). This behavior is because of the growth of nanoparticles in the matrix materials, and can be explained by changes in the amount of confinement as a consequence of particle size variation. SEM images also confirm that different numbers of cycles lead to different morphology. Frequency-dependent dielectric properties and a.c. electrical conductivity of the samples prepared by use of different numbers of cycles of SILAR were investigated, and comparative studies on some electrophysical properties of the samples are reported. Experimental results show that values of the dielectric constant (ε), dielectric loss (ε′), dielectric loss tangent (tanδ), the real (M) and imaginary (M′) parts of electric modulus, and σ a.c. are highly dependent on the frequency and the number of cycles. It can be concluded that changing the frequency and the number of cycles substantially alters both the dielectric properties and a.c. electrical conductivity of the samples. © 2014 TMS.

The new title compound is synthesized by reaction of a stoichiometric mixture of Li3[BN2] and EuCl3 (sealed Nb ampule, 850 °C, 12 h).

In this phase II study, activity and safety of neoadjuvant regional hyperthermia (RHT) combined with chemotherapy was investigated in 59 patients with primary advanced or recurrent high-risk soft-tissue sarcoma (STS). Patients received four EIA cycles consisting of etoposide, ifosfamide and doxorubicin combined with RHT followed by surgical resection and adjuvant treatment. The overall objective response (OR) rate was 17%, with one complete (2%) and eight partial (15%) responses. In addition, 13 minor reponses (25%) were seen. At time of surgery, complete necrosis (pCR) occurred in 6 patients and >75% necrosis (favourable histological response (FHR)) in 12 patients. At the completion of protocol treatment, 36 patients were rendered disease-free which was significantly associated with the initial radiographic and/or pathological tumour response ( P =0.004). Treatment-related toxicity was acceptable overall. At a medium follow-up of 82 months, local treatment failure occurred in 33 patients, median overall survival (OS) was 52 months, and the 5-year survival rate was 49% (95% confidence interval (CI): 36–61%). OS which did not differ for extremity versus non-extremity STS ( P =0.21) was better for patients responding to EIA combined with RHT ( P

We have fabricated Au/n-Si and Au/PVA:Zn/n-Si Schottky barrier diodes (SBDs) to investigate the effect of organic interfacial layer on the main electrical characteristics. Zn doped poly(vinyl alcohol) (PVA:Zn) was successfully deposited on n-Si substrate by using the electrospinning system and surface morphology of PVA:Zn was presented by SEM images. The current-voltage (I-V) characteristics of these SBDs have been investigated at room temperature. The experimental results show that interfacial layer enhances the device performance in terms of ideality factor (n), zero-bias barrier height (Phi(BO)), series resistance (R-s), and shunt resistance (R-sh) with values of 1.38, 0.75 eV, 97.64 Omega, and 203 MO whereas those of Au/n-Si SBD are found as 1.65, 0.62 eV, 164.15 Omega and 0.597 M Omega, respectively. Also, this interfacial layer at metal/semiconductor (M/S) interface leads to a decrease in the magnitude of leakage current and density of interface states (N-ss). The values of N-ss range from 1.36 x 10(12) at E-c-0.569 eV to 1.35 x 10(13) eV(-1) cm(-2) at E-c-0.387 eV for Au/PVA:Zn/n-Si SBD and 3.34 x 10(12) at E-c-0.560 eV to 1.35 x 10(13) eV(-1) cm(-2) at E-c-0.424 eV for Au/n-Si SBD. The analysis of experimental results reveals that the existence of PVA:Zn interfacial layer improves the performance of such devices. (C) 2013 Elsevier Ltd. All rights reserved.

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In this study, the forward and reverse bias current-voltage (I-V) characteristics of Au/Zinc acetate doped polyvinyl alcohol/n-Si Schottky barrier diodes (SBDs) have been investigated over the temperature range of 80-400 K. The values of zero-bias barrier height evaluated from forward and reverse bias I-V data, (Phi(BFo)) and (Phi(BRo)), increase with increasing temperature, and a discrepancy is observed between the values of Phi(BFo) and Phi(BRo). Because the apparent barrier height (BH) seen from metal to semiconductor is higher than the one seen from semiconductor to metal, the obtained value of Phi(BFo) is always greater than Phi(BRo) value. The difference between them is almost the same as the Fermi energy level. The crossing of the experimental forward bias semilogarithmic ln I-V plots appears as an abnormality when compared to the conventional behavior of ideal SBDs. This behavior was attributed to the lack of free charge at a low temperature and could be expected in the temperature region where there is no carrier freezing out, which is non-negligible at low temperatures. Prior to intersection, the voltage dependent value of resistance (R-i) obtained from Ohm's law decreases with increasing temperature, but it begins to increase after this intersection point. Such an increase in Phi(Bo) and series resistance (R-s) with temperature corresponding to high voltage region is in obvious disagreement with the reported negative temperature coefficients. However, the value of shunt resistance (R-sh) corresponding to a low or negative voltage region decreases with increasing temperature. In addition, the temperature dependent energy density distribution profiles of interface states (N-ss) were obtained from forward bias I-V measurements by taking into account the bias dependence of the effective barrier height (Phi(e)) and R-s of the device, and the values of Nss without considering Rs are almost one order of magnitude larger than N-ss when considering Rs value. (C) 2011 American Institute of Physics. [doi:10.1063/1.3552599]

Gokcen, Muharrem/0000-0001-9063-3028 WOS: 000295468900025 The effects of interfacial insulator layer, interface states (N-ss) and series resistance (R-s) on the electrical characteristics of Au/n-Si structures have been investigated using forward and reverse bias current-voltage (I-V) characteristics at room temperature. Therefore, Au/n-Si Schottky barrier diodes (SBDs) were fabricated as SBDs with and without insulator SnO2 layer to explain the effect of insulator layer on main electrical parameters. The values of ideality factor (n), R-s and barrier height (Phi(Bo)) were calculated from ln(I) vs. V plots and Cheung methods. The energy density distribution profile of the interface states was obtained from the forward bias I-V data by taking bias dependence of ideality factor, effective barrier height (Phi(e)) and R-s into account for MS and MIS SBDs. It was found that N-ss values increase from at about mid-gap energy of Si to bottom of conductance band edge of both SBDs and the MIS SBD's N-ss values are 5-10 times lower than those of MS SBD's. An apparent exponential increase from the mid-gap towards the bottom of conductance band is observed for both SBDs' (MS and MIS) interface states obtained without taking R-s into account. (C) 2011 Elsevier B.V. All rights reserved. Duzce UniversityDuzce University [2010.05.02.056] This work is supported by Duzce University Scientific Research Project (Project no. 2010.05.02.056).

1st International Congress on Advances in Applied Physics and Materials Science (APMAS) -- MAY 12-15, 2011 -- Antalya, TURKEY, WOS: 000301042000058, This study presents the effect of illumination on main electrical parameters of Schottky barrier diode (SBD). The admittance (capacitance-voltage (C-V) and conductance-voltage (G/omega-V)) characteristics of Au/Zinc acetate doped polyvinyl alcohol (PVA:Zn)/n-Si SBD were investigated in dark and under various illumination intensities. Experimental results demonstrate that the C-V plots give a peak due to the illumination induced interface states or electron-hole pairs at metal/semiconductor (M/S) interface. The C-2-V plots were also drawn to determine main electrical parameters such as doping concentration (N-D), depletion layer width (W-D) and barrier height (Phi(B)(C-V)) of device. In addition, the voltage dependence R-s values were obtained from C-V and G/omega-V data by using Nicollian and Brews method. In order to obtain the real diode capacitance and conductance, the high frequency (1 MHz) C-m and G(m)/w values were corrected for the effect of series resistance. All these observations confirm that both C-V and G/w-V characteristics were strongly affected by illumination., Istanbul Kultur Univ, Gebze Inst Technol, Doga Nanobiotech Inc, Terra Lab Inc, LOT Oriel Grp, PHYWE, Delta Elekt Inc

The quantum-well (QW) lasers are the most important optoelectronic devices in many application fields and the current-transport mechanisms (CTMs) are strongly depend on temperature and voltage. Therefore, we have examined the samples in the temperature range of 80-360K. The electrical parameters such as saturation current (I-o), zero-bias barrier height (Phi(Bo)), ideality factor (n) and series resistance (R-s), were obtained from the forward bias 1-V data. The n and Phi(Bo) values change from 3.49 and 1.313 eV (at 80K) to 1.73 and 0.492 eV (at 360 K), respectively. These values of n indicate that the thermionic field emission (TFE) mechanism is dominated the others, particularly at low temperature (80-170K). High values of n were attributed to image force lowering of the barrier height, tunneling current at low temperature, generation-recombination current within the space charge region and the existence of interface states at metal/semiconductor interface. The Phi(Bo) values do not have to be absolutely correct, especially when there are more CTMs present in a given temperature interval. Also, n and R-s were found to be extremely dependent on the contributions of particular CTMs to the total current; the ratio of which to the TE theory increases with the increasing temperature. The Phi(Bo) and activation energy (E-a) values decrease with the linearly increasing temperature and voltage. In addition, double-logarithmic plots of the forward bias I-V characteristics have shown two distinct linear regions in the whole temperature range. SCLC mechanism may be dominated CTMs especially at high temperature regime namely regime II. (C) 2010 Elsevier B.V. All rights reserved.

The forward bias current-voltage (I-V) characteristics of Au/n-Si Schottky barrier diodes (SBDs) with Zn doped poly (vinyl alcohol) (PVA:Zn) interfacial layer have been investigated in the wide temperature range of 80-400 K. The conventional Richardson plot of the ln(I-o/T-2) versus q/kT has two linear regions: the first region (200-400 K) and the second region (80-170 K). The values of activation energy (E-a) and Richardson constant (A*) were obtained from this plot and especially the values of A* are much lower than the known theoretical value for n-type Si. Also the value of E-a is almost equal to the half of the band gap energy of Si. Therefore, the Phi(ap) versus q/2kT plot was drawn to obtain the evidence of a Gaussian distribution (GD) of barrier heights (BHs) and it shows two linear region similar to ln(I-o)/T-2 versus q/kT plot. The analysis of I-V data based on thermionic emission of the Au/PVA:Zn/n-Si SBDs has revealed the existence of double GD with mean BH values (Phi(B0)) of 1.06 eV and 0.86 eV with standard deviation (sigma) of 0.110 eV and 0.087 V, respectively. Thus, we modified ln(I-o/T-2)-(q sigma)(2)/2(kT)(2) versus q/kT plot for two temperature regions (200-400 K and 80-170 K) and it gives renewed mean BHs (Phi) over bar (B0) values as 1.06 eV and 0.85 eV with Richardson constant (A*) values 121 A/cm(2) K-2 and 80.4 A/cm(2) K-2, respectively. This obtained value of A* = 121 A/cm(2) K-2 is very close to the known theoretical value of 120 A/cm(2) K-2 for n-type Si. (C) 2010 American Institute of Physics. [doi:10.1063/1.3468376]

Illumination intensity effects on the electrical characteristics of Al–TiW–Pd 2 Si/ n -Si Schottky structures have been investigated in this study for the first time. The electrical parameters such as ideality factor ( n ), zero-bias-barrier height ( Φ B0 ), series resistance ( R s ), depletion layer width ( W D ) and dopping concentration ( N D ) of Al–TiW–Pd 2 Si/ n -Si Schottky barrier diodes (SBDs) have been investigated by using the forward and reverse bias current–voltage ( I – V ), capacitance–voltage ( C – V ) and conductance–voltage ( G / ω - V ) measurements in dark and under illumination conditions at room temperature. The values of C and G / ω increase with increasing illumination intensity due to the illumination induced electron–hole pairs in the depletion region. The density of interface states ( N ss ) distribution profiles as a function of ( E c − E ss ) was extracted from the forward I – V measurements by taking into account the bias dependence of the effective barrier heights ( Φ e ) for device in dark and under various illumination intensities. The high values of N ss were responsible for the nonideal behavior of I – V , C – V and G / ω characteristics. The values of R s obtained from Cheung and Nicollian methods decrease with increasing illumination intensity. The high values of n and R s have been attributed to the particular distribution of N ss , surface preparation, inhomogeneity of interfacial layer and barrier height at metal/semiconductor (M/S) interface. As a result, the characteristics of SBD are affected not only in N ss but also in R s , and these two parameters strongly influence the electrical parameters.

The profile of the interface state densities (N-ss) and series resistances (R-s) effect on capacitance-voltage (C-V) and conductance-voltage (G/omega-V) of (Ni/Au)/AlxGa1-xN/AlN/GaN heterostructures as a function of the temperature have been investigated at 1 MHz. The admittance method allows us to obtain the parameters characterizing the metal/semiconductor interface phenomena as well as the bulk phenomena. The method revealed that the density of interface states decreases with increasing temperature. Such a behavior of N-ss can be attributed to reordering and restructure of surface charges. The value of series R-s decreases with decreasing temperature. This behavior of R-s is in obvious disagreement with that reported in the literature. It is found that the N-ss and R-s of the structure are important parameters that strongly influence the electrical parameters of (Ni/Au)/AlxGa1-xN/AlN/GaN(x = 0.22) heterostructures. In addition, in the forward bias region a negative contribution to the capacitance C has been observed, that decreases with the increasing temperature. Copyright (C) 2010 John Wiley & Sons, Ltd.

The purpose of this study is to analyze interface states (N-ss) in Au/TiO2(Rutile)/n-Si Schottky barrier diodes (SBDs). TiO2 was deposited on a n-Si substrate by reactive magnetron sputtering and annealed at 900 degrees C for 4 h in atmosphere to obtain rutile phase. The current voltage (I-V) characteristics of SBDs were measured at room temperature. From the I-V characteristics of the SBDs ideality factor (n) and zero-bias barrier height values (phi(Bo)) 2.3 and 0.76 eV, respectively, were obtained. The N-ss distribution profile (N-ss) as a function of (E-c - E-ss) was extracted from the forward-bias I-V measurements by taking account effective barrier height and (phi(e)) and series resistance (R-s) for the Schottky diode. Nss values ranges from 4.3 x 10(12) cm(-2) eV(-1) in (E-c - 0.33) eV and 8.0 x 10(13) cm(-2) eV(-1) in (E-c - 0.33) eV. These values are better than in the literature values where TiO2 was deposited sol-gel method. The N-ss values taking into R-s were lower than without R-s. This shows that Rs should be taking account. Copyright (C) 2010 John Wiley & Sons, Ltd.

The single phase clathrate-I Ba(8)Ge(43)square(3) (space group Ia3d (no. 230), a = 21.307(1) A) was synthesized by quenching the melt between cold steel plates. Specimens for physical property measurements were characterized by microstructure analysis and X-ray diffraction on polycrystalline samples as well as single crystals. Transport properties including thermopower, electrical resistivity, thermal conductivity and specific heat were investigated in a temperature range of 2-673 K. The electrical resistivity exhibits a metal-like temperature dependence below 300 K turning into a semiconductor-like behaviour above 300 K. The analysis of the specific heat at low temperature indicates a finite density of states at the Fermi level, thus corroborating the metallic character below 300 K. The temperature dependence of the specific heat was modelled assuming Einstein-like localized vibrations of Ba atoms inside the cages of the Ge framework. A conventional crystal-like behaviour of the thermal conductivity with a low lattice contribution (kappa(l)(300 K) = 2.7 W m(-1) K(-1)) has been evidenced.

An integral approach has been used to analyze the development of the free convection boundary layer on heated concave surfaces, such as those in horizontal cylinders or a sphere. Based on the non-dimensional laminar and turbulent velocity and temperature profiles closed form expressions for the boundary layer thickness, velocity scale as well as the boundary layer commencement after the point of instability are obtained. In addition, the mass flowrate to the thermal stratified region is given.

In this study, we have examined Au/TiO2/n-Si Schottky barrier diodes (SBDs), in order to interpret in detail the experimental observed non-ideal current-voltage-temperature (I-V-T) characteristics. I-V characteristics were measured in the wide temperature range of 80-400 K. TiO2 was deposited on n-Si substrate by reactive magnetron sputtering. The zero-bias barrier height (phi(B0)) and ideality factor (n) show strong temperature dependence. While n decreases, phi(B0) increases with increasing temperature. Experimental results show that the current across the SBDs may be greatly influenced by the existence of Schottky barrier height (SBH) inhomogeneity. These temperature behaviors have been explained on the basis of the thermionic emission (TE) theory with Gaussian distribution (GD) of the barrier heights (BHs) due to BH inhomogeneities at metal-semiconductor (M/S) interface. From this assumptions, obtaining Richardson constant value of the A* 121.01 A/cm(2)K(2) is perfect agreement with the theoretical value of 120 A/cm(2)K(2) for n-type Si. Hence, behaviors of the forward-bias I-V characteristics of the Au/TiO2/n-Si (SBDs) can be successfully explained on the basis of a TE mechanism with a double Gaussian distribution of the BHs. (C) 2009 Elsevier Ltd. All rights reserved.

Philadelphia chromosome-positive acute lymphoblastic leukaemia (ALL) is most common in adults and is associated with poor prognosis. Since karyotypic identification of the Philadelphia translocation has been hampered by technical difficulties, we used the polymerase chain reaction (PCR) to look for the BCR-ABL rearrangement in stored samples from a selected group of 314 German ALL patients. BCR-ABL transcripts were found in 77 of 179 adults and were restricted to those with B-precursor leukaemias. 55% of adult common ALL patients had BCR-ABL and its presence correlated with poor overall survival and remission duration. Of 135 children with common ALL, 5 (6%) primary cases and 8 (17%) with recurrent neoplasias were PCR-positive. We recommend prospective evaluation of BCR-ABL analysis with PCR in patients with a B-precursor leukaemia.

The lineage affinity of 57 cases of acute unclassified leukemias (AUL) was reevaluated by ultrastructural analysis of peroxidase expression (POEM) in combination with immunophenotyping and analysis of immunoglobulin gene configuration. Twenty-three cases of myeloid and three cases of megakaryocytic differentiation were identified by detection of ultrastructural myeloperoxidase (UMPO) and platelet peroxidase (UPPO). No significant correlation was noted between myeloid marker expression and POEM positivity, whereas presence of CD 19 or CD 24 antigen significantly correlated with POEM negativity (P = .001 and .023, respectively). Ig gene rearrangements including oligoclonal patterns were also recorded in 8 of 14 UMPO+ patients tested. Fourteen UMPO+ patients responded poorly to an ALL/AUL chemotherapy regimen with a low complete remission (CR) rate of 29% and a short median remission duration (MRD) of 5 months. The POEM- patients proved very heterogenous with respect to immunophenotype and Ig gene rearrangement. Seventeen of 21 patients tested had Ig gene rearrangements, including oligoclonal patterns. Combined data suggest that a proportion of these cases probably derive from a very immature lymphoid progenitor cell, particularly because 15 POEM- AUL patients showed a response to ALL/AUL chemotherapy comparable to that observed in patients with definitive acute lymphoblastic leukemia (ALL) (CR rate 80%, MRD 20 months). Thus, ultrastructural analysis of peroxidase expression can provide decisive prognostic information in AUL patients.

Radiotherapy brings a tumor patient into a special life situation in which different variables play a role of often unknown importance. The goal of this study was to investigate disease specific stress of tumor patients at the beginning of radiotherapy with established psychodiagnostic questionnaires and to evaluate the effect on psychosocial support requirement in order to reduce stress and to improve quality of life and compliance during radiotherapeutical treatment.732 patients were screened, of whom 446 (60.9%) fulfilled the criteria for inclusion (refusals 21.0%, low karnorsky performance status 6.6%, management problems 3.4%, language barriers 3.0%, cognitive restrictions 2.6%, death 2.5%). Disease specific aspects of stress in the questionnaire (Fragebogen zur Belastung von Krebspatienten, FBK), life situation (LS) and self-defined care requirements (BB) (Figure 1) were self-rated by patients with different tumor types before radiotherapy. Medical and sociodemographic data were also documented. We investigated 446 patients (262 male, 184 female; median age 60.0 years) with different diagnoses (Table 1).Stress was observed mainly due to reduction of efficiency, anxiety and pain on the subscales (Figure 2). Women had a significant higher stress on subscales of pain (p = 0.016) and anxiety (p = 0.009) (Table 2), patients younger than 45 years in the subscale information (p = 0.002) and patients older than 45 and younger than 60 years in the subscale anxiety (p = 0.002) and the total score (p = 0.003) (Table 3). Patients with mamma carcinoma had the highest the stress (Table 4). The maximum percentages of patients under high stress were found for the subscales of efficiency (43%) and anxiety (40%). The support requirement was characterized by the need of more medical information and dialogue with the doctor. We saw a significant correlation of high stress and high care requirement (Tables 5 and 6).Psychosocial support should be founded on psychosocial stress diagnostic and self-defined care requirement.

In this phase II study, activity and safety of neoadjuvant regional hyperthermia (RHT) combined with chemotherapy was investigated in 59 patients with primary advanced or recurrent high-risk soft-tissue sarcoma (STS). Patients received four EIA cycles consisting of etoposide, ifosfamide and doxorubicin combined with RHT followed by surgical resection and adjuvant treatment. The overall objective response (OR) rate was 17%, with one complete (2%) and eight partial (15%) responses. In addition, 13 minor responses (25%) were seen. At time of surgery, complete necrosis (pCR) occurred in 6 patients and75% necrosis (favourable histological response (FHR)) in 12 patients. At the completion of protocol treatment, 36 patients were rendered disease-free which was significantly associated with the initial radiographic and/or pathological tumour response (P=0.004). Treatment-related toxicity was acceptable overall. At a medium follow-up of 82 months, local treatment failure occurred in 33 patients, median overall survival (OS) was 52 months, and the 5-year survival rate was 49% (95% confidence interval (CI): 36-61%). OS which did not differ for extremity versus non-extremity STS (P=0.21) was better for patients responding to EIA combined with RHT (P0.01).

BACKGROUND: In the framework of a prospective longitudinal study, the quality of life (QoL) and support requirements of patients from a university hospital department of radiotherapy were evaluated for the first time by means of established psychodiagnostic questionnaires. PATIENTS AND METHODS: At first, 732 patients were screened, of whom 446 (60.9%) fulfilled the criteria for inclusion; 39.1% did not (refusals 21.0%, low Karnofsky performance status 6.6%, management problems 3.4%, language barriers 3.0%, cognitive restrictions 2.6%, death 2.5%). Disease-specific aspects of QoL (Functional Assessment of Cancer Treatment - General, FACT-G) and moderating variables [Social Support Scale (SSS), Disease Coping (FKV), Self-Assessment Depression Scale (SDS), and Self-Defined Care Requirements (BB)] were self-rated by patients with different tumor types before radiotherapy (T1), after radiotherapy (T2), and 6 weeks after the end of radiotherapy (T3). We studied 265 patients (157 male, 108 female; median age 58.6 years) with complete data of three time points. RESULTS: In general, QoL of patients decreased significantly over all time points in all subscales. Social support was rated high and remained constant throughout the treatment. Apparent coping mechanisms were active problem-oriented coping, leisure activities, and self-support. The patients' depression proved to be an important and constant factor without significant changes. The support requirement is characterized by the need for more medical information and dialogue with a physician. CONCLUSIONS: Early specific support from personnel with radiotherapeutic skills, during the disease-coping process as well as during rehabilitation, should be a permanent component of an integrated radiooncological treatment schedule. Copyright 2000 S. Karger GmbH, Freiburg

In contrast to childhood acute lymphoblastic leukemia (ALL), the cell-biological features, clinical characteristics, and treatment outcome of CD10(-) pro-B ALL have not yet been determined in larger series of adult patients. Therefore, we studied 57 adult patients with newly diagnosed pro-B ALL (median age, 30 years) enrolled in two consecutive German multicenter ALL studies (03/87 and 04/89). Extensive immunophenotypic characterization of leukemic blasts could be performed on all patients, whereas adequate cytogenetic data were available in 33 cases and molecular studies in 18 cases, using reverse transcription-polymerase chain reaction to detect MLL-AF-4 transcripts. Twenty-two patients demonstrated a t(4;11)(q21;q23) and/or MLL-AF-4 rearrangements, and 6 patients had other structural abnormalities, including a t(9;22)(q34;q11) (N = 2). Nine patients had a normal karyotype. Patients with 11q23 abnormalities tended to be younger (median age, 29 years) and were characterized by male predominance (64%), hyperleukocytosis (median leukocyte count, 168 x 10(9)/L), and a frequent coexpression of CD65s (64%) as compared with patients with other cytogenetic abnormalities or a normal karyotype. Twelve of 16 (75%) pro-B ALL patients in study 03/87 and 30 of 41 (73%) in study 04/89 achieved a complete remission (CR). Sixteen of 30 patients in study 04/89 remain in continuous CR (CCR) in contrast to only 2 of 12 patients in study 03/87. Interestingly, all 7 patients treated with high-dose cytarabine and mitoxantrone as consolidation in study 04/89 remain alive and leukemia-free. One patient in study 03/87 and 8 in study 04/89 underwent autologous (N = 2) or allogeneic (N = 7) bone marrow transplantation (BMT). The median remission duration was 420 days for patients in study 03/87 and has not yet been reached in study 04/89. The median survival time of all pro-B ALL patients was 571 days in study 03/87 and 747 days in study 04/89. Among the 22 patients with a t(4;11) and/or MLL-AF-4 rearrangements, 17 achieved a CR and 8 are still in CCR, of whom 4 underwent an allogeneic BMT. Remission duration and overall survival did not differ significantly between pro-B ALL patients with 11q23 abnormalities and those with a normal karyotype or other structural abnormalities. These data indicate that intensification of postremission treatment may improve the prognosis of adult pro-B ALL, including patients with a t(4;11).

Among high-grade malignant non-Hodgkin's lymphomas the updated Kiel classification identifies three major B-cell entities: centroblastic (CB), B-immunoblastic (B-IB), and B-large cell anaplastic (Ki-1+) (now termed anaplastic large cell [CD30+], [B-ALC]). The clinical prognostic relevance of this distinction was evaluated in a randomized prospective treatment trial (COP-BLAM/IMVP-16 regimen randomly combined +/- radiotherapy in complete responders) conducted in adult (age 15 to 75) patients with Ann Arbor stage II-IV disease (n = 219) diagnosed by optimal histomorphology (Giemsa staining) and by immunohistochemistry. Overall survival was significantly better in CB lymphoma as compared to B-IB (P = .0002) or B-ALC (P = .046). Relapse-free survival was worse for B-IB (P = .0003) as compared to CB lymphomas. The prognostic differences between CB and B-IB were confirmed by multivariate analyses including the risk factors of the International Index. Overall survival was significantly determined by performance status (P = .0003), serum-LDH (P = .036), and B-IB histology subtype (P = .036). Relapse-free survival was influenced by age (P = .007) and histological subtype (P = .007). Thus, the diagnosis of the CB and B-IB lymphomas by the histological criteria of the Kiel classification was identified as an independent prognostic factor in diffuse large B-cell lymphomas.

One of the common features of the five Public Health Research Centres of Germany lies in quality assurance and quality improvement of their research activities. The institutionalisation of systems of quality improvement of Public Health Research has to be regarded as innovative, hitherto unparalleled, in the German context. The article deals with the demands on quality improvement confronting empirical research, the possibilities of coming to terms with this challenge, and still unresolved problems of implementation. Demands will be outlined in discussing quality criteria and processes of empirical research, paying special attention to differences between qualitative and quantitative designs of inquiry. The concept of quality improvement, developed in the Munich Public Health Research Centre, applies two basic strategies to meet these demands: enhancement of the transparency of the research process, and the training of research staff. Instruments for quality improvement are introduced: some of them may be applied by the research team itself (such as study protocol, research diary, team discussion) some of them have to be realised by external staff, especially responsible for the process of quality improvement, in cooperation with the research team (quality circles, training, compilation of written material). In conclusion, the implementation of instruments of this kind is discussed, concentrating on the problematic cooperation between research team and external staff.