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Limits on light emission from silicon

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Chinese Optics Letters 2009年第4期7卷 268-270页

作者： peter Würfel Institut für Angewandte Physik Universitt KarlsruheD-76128 KarlsruheGermany

Although silicon is an indirect semiconductor, light emission from silicon is governed by the same gener- alized Planck＇s radiation law as the emission from direct semiconductors. The emission intensity is given by the absorptance of the volume in which there is a difference of the quasi Fermi energies. A difference of the Fermi energies may result h＇om the absorption of external light （photoluminescence） or from the injection of electrons and holes via selective contacts （electroluminescence）. The quantum efficiency may be larger than 0.5 for carrier densities below 10^15 cm^-3. At larger densities, non-radiative recombination, in particular Auger recombination dominates. At all carrier densities, the relation between emission intensity and difference of the quasi Fermi energies is maintained. since this difference is equal to the voltage of a properly designed solar cell, luminescence is the key indicator of material quality for solar cells.

关键词： Carrier concentration Fermi level Light Light emission Photoluminescence semiconducting silicon silicon

Comparison of different lymph node staging systems in prognosis of gastric cancer:a bi-institutional study from Hungary

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Chinese Journal of Cancer Research 2017年第4期29卷 323-332页

作者： Dezso Toth Adrienn Bfra Zsolt Vargal Miklos Torok peter peter Akosy Department of General surgery Kenezy Gyula Teaching Hospital Debrecen 4031 Hungary Department of General Thoracic and Vascular Surgery Kaposi M6r Teaching Hospital Kaposv~r 7400 Hungary Department of Pathology Ken6zy Gyula Teaching Hospital Debrecen 4031 Hungary Department of Oncology Kan6zy Gyula Teaching Hospital Debrecen 4031 Hungary

Objective： The Union for International Cancer Control （UICC） Node （N） classification is the most common used staging method for the prognosis of gastric cancer. It demands adequate, at least 16 lymph nodes （LNs） to be dissected; therefore different staging systems were invented. Methods： Between March 2005 and March 2010, 164 patients were evaluated at the Department of General surgery in the Ken^zy Gyula Hospital and at the Department of General, Thoracic and Vascular surgery in the Kaposi M6r Hospital. The 6th, 7th and 8th UICC N-staging systems, the number of examined LNs, the number of harvested negative LNs, the metastatic lymph node ratio （MLR） and the log odds of positive LNs （LODDs） were determined to measure their 5-year survival rates and to compare them to each other. Results： The overall 5year survival rate for all patients was 55.5% with a median overall survival time of 102 months. The tumor stage, gender, UICC N-stages, MLR and the LODDs were significant prognostic factors for the 5-year survival with univariate analysis. The 6th UICC N-stage did not follow the adequate risk in comparing N2 vs. NO and N3 vs. NO with multivariate investigation. Comparison of performances of the residual N classifications proved that the LODDs system was first in the prediction of prognosis during the evaluation of all patients and in cases with less than 16 harvested LNs. The MLR gave the best prognostic prediction when adequate （more than or equal to 16） lymphadenectomy was performed. Conclusions： We suggest the application of LODDs system routinely in western patients and the usage of MLR classification in cases with extended lymphadenectomy.

关键词： Gastric cancer lymph node metastasis prognosis staging system survival

Association between dairy intake,lipids and vascular structure and function in diabetes

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World Journal of Diabetes 2017年第5期8卷 202-212页

作者： Kristina s petersen Jennifer B Keogh Natalie Lister Jacquelyn M Weir peter J Meikle peter M Clifton school of Pharmacy and Medical sciences and sansom Institute for Health Research University of South Australia Baker IDI Heart and Diabetes Institute

AIM To determine lipid species that change in response to a change in dairy consumption. In addition, to investigate whether dairy associated lipid species are correlated with changes in measures of vascular structure and *** A 12-mo randomised controlled trial was conducted to determine the effect of increased consumption of fruit, vegetables and dairy, compared to usual diet, on measures of vascular structure and function in adults with type 1 and type 2 diabetes(n = 108). Thispaper comprises post-hoc analyses investigating the relationship between dairy intake, serum lipid species and vascular health. Central and peripheral blood pressure, carotid femoral pulse wave velocity, augmentation index, serum lipid species and dietary intake were measured at baseline and 3-mo. Common carotid artery intima media thickness was measured at baseline and *** serum lipid species [lysophosphatidylcholine(LPC) 14:0, LPC 15:0, LPC 16:1, phosphatidylcholine(PC) 29:0 PC 30:0, PC 31:0 and cholesterol ester(CE) 14:0] were associated with the change in full fat dairy consumption(rho 0.19-0.25; P some lipids was positively associated with the 3-mo change in central systolic [LPC 14:0(rho 0.30; P = 0.007), PC 30:0(rho 0.28; P = 0.010)] and diastolic blood pressure [LPC 14:0(rho 0.32; P = 0.004), LPC 15:0(rho 0.23; P = 0.04), LPC 16:1(rho 0.23; P = 0.035), PC 29:0(rho 0.28; P = 0.01), PC 30:0(rho 0.36; P = 0.001), PC 31:0(rho 0.30; P = 0.007)] and 12-mo change in common carotid artery intimal medial thickness [CE 14:0(rho 0.22; P = 0.02)]. Pulse wave velocity and augmentation index were unrelated to dairy and lipid *** An increase in dairy associated lipids appears to be associated with an increase in blood pressure and common carotid intimal medial thickness.

关键词： Lipids Phospholipids Atherosclerosis Dairy Lysophosphatidylcholine Lipidomics Carotid intima media thickness Pulse wave velocity Diabetes

THE UsE OF PLANE WAVEs TO APPROXIMATE WAVE PROPAGATION IN ANIsOTROPIC MEDIA

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Journal of Computational Mathematics 2007年第3期25卷 350-367页

作者： Tomi Huttunen peter Monk Department of Physics University of KuopioP.O.Box 1627FIN-70211 KuopioFinland Department of Mathematical sciences University of DelawareNewarkDE 19716USA

In this paper we extend the standard Ultra Weak Variational Formulation （UWVF） of Maxwell＇s equations in an isotropic medium to the case of an anisotropic medium. We verify that the underlying theoretical framework carries over to anisotropic media （however error estimates are not yet available） and completely describe the new scheme. We then consider TM mode scattering, show how this results in a Helmholtz equation in two dimensions with an anisotropic coefficient and demonstrate how to formulate the UWVF for it. In one special case, convergence can be proved. We then show some numerical results that suggest that the UWVF can successfully simulate wave propagation in anisotropic media.

关键词： Ultra weak Maxwell Plane wave Anisotropic medium.

Adaptive nonlinear model predictive control design of a flexible-link manipulator with uncertain parameters

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Acta Mechanica sinica 2017年第3期33卷 529-542页

作者： Fabian schnelle peter Eberhard Institute of Engineering and Computational Mechanics University of Stuttgart

This paper presents a novel adaptive nonlinear model predictive control design for trajectory tracking of flexible-link manipulators consisting of feedback linearization, linear model predictive control, and unscented Kalman filtering. Reducing the nonlinear system to a linear system by feedback linearization simplifies the optimization problem of the model predictive controller significantly, which, however, is no longer linear in the presence of parameter uncertainties and can potentially lead to an undesired dynamical behaviour. An unscented Kalman filter is used to approximate the dynamics of the prediction model by an online parameter estimation, which leads to an adaptation of the optimization problem in each time step and thus to a better prediction and an improved input action. Finally, a detailed fuzzy-arithmetic analysis is performed in order to quantify the effect of the uncertainties on the control structure and to derive robustness assessments. The control structure is applied to a serial manipulator with two flexible links containing uncertain model parameters and acting in three-dimensional space.

关键词： Model predictive control Feedback linearization Unscented Kalman filter Flexible-link manipulator Fuzzy-arithmetical analysis

Impact of natural disturbance, forest management and vegetation cover on topsoil biochemical characteristics of Tatra Mts.(slovakia)

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Journal of Mountain science 2020年第6期17卷 1294-1309页

作者： Jana GáFRIKOVá Milan ZVARíK peter HANAJíK Marek súLOVsKY Ivana VYKOUKOVá Faculty of Natural sciences Comenius UniversityBratislava84104Slovak Republic Faculty of Mathematics Physics and InformaticsComenius UniversityBratislava84104Slovak Republic Water Research Institute Bratislava81249Slovak Republic

Perturbations caused by windstorms usually lead to the harvesting and clearcutting of fallen trees and wood debris,especially in the areas of managed forest *** shifts in soils due to management practices play a crucial role in the restoration and maintaining of key ecosystem *** paper focuses on topsoil chemical properties in relation to vegetation type(trees,shrubs and herbs)evolving at windstorm damaged(in 2004)areas with former Norway spruce(Picea abies)forests in the Tatra ***(slovakia).We assessed the content of topsoil organic matter fractions(extractives,holocellulose(HC)and lignin(Lig)),carbon in microbial biomass(Cmic),soil organic matter(sOM)and the content of elements N,C,H and *** study plots represent different types of post-windthrow disturbance history/regime:wooden debris extraction(EXT),wooden debris not extracted(NEX),wooden debris extraction followed by wildfire(FIR),affected by the windstorm in 2014 with the subsequent wooden debris extraction(REX)and unaffected(REF).Our results revealed significant differences among sites in the content of dichloromethane extractives(EXT *** and FIR),acetone extractives(NEX ***,FIR and REF),ethanol extractives(FIR ***,NEX and REF),water extractives(FIR ***,NEX)and Cmic(EXT ***,FIR and REF).The topsoil of Vaccinium myrtillus and Picea abies showed a higher ratio of C/N,N/Lig,and Lig/HC compared to Rubus idaeus,Avenella flexuosa,Calamagrostis villosa,and Larix *** content of N,C,H and s varied between topsoil with shrubs(Vaccinium myrtillus,Rubus idaeus)and grasses(Avenella flexuosa,Calamagrostis villosa).A positive correlation between soil organic matter(sOM)and polar extractives(r=0.81)and a negative correlation between sOM and HC(r=-0.83)was *** carbon content in microbial biomass(Cmic)is positively correlated with acid soluble lignin(AsL)(r=0.85).We also identified a strong correlation between Klason lignin(KL)and the Lig/HC ratio(r=0.97).

关键词： Windthrow Wildfire Organic matter fractions Vegetation type Norway spruce Topsoil chemical properties

spatially-structured sharing Technique for Multimodal Problems

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Journal of Computer science & Technology 2008年第1期23卷 64-76页

作者： Grant Dick peter Whigham Department of Information science University of OtagoDunedin

spatially-structured populations are one approach to increasing genetic diversity in an evolutionary algorithm （EA）. However, they are susceptible to convergence to a single peak in a multimodal fitness landscape. Niching methods, such as fitness sharing, allow an EA to maintain multiple solutions in a single population, however they have rarely been used in conjunction with spatially-structured populations. This paper introduces local sharing, a method that applies sharing to the overlapping demes of a spatially-structured population. The combination of these two methods succeeds in maintaining multiple solutions in problems that have previously proved difficult for sharing alone （and vice-versa）.

关键词： evolutionary algorithm multimodal problem domain sharing spatially-structured population

Influence of entrainer recycle for batch heteroazeotropic distillation

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Frontiers of Chemical science and Engineering 2018年第4期12卷 643-659页

作者： Laszlo Hegely peter Lang Department of Building service and Process Engineering Faculty of Mechanical Engineering Budapest University of Technology and EconomicsMuegyetem rkp.3-9Hungary

Dehydration of isopropanol applying batch heteroazeotropic distillation with toluene as entrainer (E) is investigated. The composition of the feed is near to that of the isopropanol (A)-water (B) azeotrope. The effects of recycling the entrainer and the off-cut are studied by dynamic simulation with a professional flow-sheet simulator. Three consecutive batches (one production cycle) is studied. Both operational modes (Mode I: decantation after distillation and Mode II: decantation during distillation) are simulated. For Mode II, calculations are performed both for strategy A (distillate from the aqueous (E-lean) phase only) and strategy B (partial withdrawal of the organic (E-rich phase), as well). The E-rich phase, the final column hold-up and the off-cut (Mode II only) are recycled to the next batch. The influence of the following parameters are determined: quantity of entrainer, reflux ratios of the steps. The variations caused by the recycling in the 2nd and 3rd batches are also shown. The best results (lowest specific energy demand and highest recovery of A) are obtained by Mode II, strategy A. Recycling increases the recovery, and drastically diminishes the entrainer consumption. However, it makes the production slower and decreases the quantity of fresh feed that can be processed.

关键词： batch distillation heteroazeotropic distillation operational policies off-cut recycle entrainer

Prognostic value of baseline FDG uptake on PET-CT in esophageal carcinoma

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World Journal of Gastrointestinal Oncology 2014年第5期6卷 139-144页

作者： Omar s Al-Taan Amar Eltweri David sharpe peter M Rodgers sukhbir s Ubhi David J Bowrey Departments of surgery University Hospitals of Leicester Departments of Radiology University Hospitals of Leicester

AIM: To evaluate the influence of baseline maximum standardized uptake value(sUVmax) on survival in a cohort of patients, undergoing positron emission tomography-computed tomography(PET-CT) scan for esophageal carcinoma. METHODs: The pre-treatment sUVmax numeric reading was determined in patients with confirmed esophageal or junctional cancer having PET-CT scan during the time period 1st January 2007 until 31 st July 2012. A minimum follow up of 12 mo was required. Patients were subdivided into quartiles according to sUVmax value and the influence of sUVmax on survival was assessed using univariate and multivariate analysis. The following pre-treatment factors were investigated: patient characteristics, tumor characteristics and planned treatment. REsULTs: The study population was 271 patients(191male) with esophageal or junctional carcinoma. The median age was 65 years(range 40-85) and histologic subtype was adenocarcinoma in 197 patients and squamous carcinoma in 74 patients. The treatment intent was radical in 182 and palliative in 89 patients. sUVmax was linked to histologic subtype(P = 0.008), tumor site(P = 0.01) and Union for International Cancer Control(UICC) stage(P sis, prognosis was significantly associated with sUVmax(P = 0.001), T-stage(P stage(P sis, only T-stage and UICC stage remained significant. CONCLUsION: Pretreatment sUVmax was not a useful marker in isolation for determining prognosis of patients with esophageal carcinoma.

关键词： Esophageal neoplasms Fluorodeoxyglucose F18 Positron emission tomography Positron emission tomography-computed tomography Prognosis