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The gluon mass generation mechanism： A concise primer

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Frontiers of physics 2016年第2期11卷 131-148页

作者： A. c. Aguilar d. Binosi J. Papavassilioua University of campinas (UNIcAMP) "Gleb Wataghin" Institute of Physics 13083-859 Campinas SP Brazil European centre for Theoretical Studies in Nuclear Physics and Related Areas (EcT^＊) and Fondazione Bruno Kessler Villa Tambosi Strada delle Tabarelle 286 1-38123 Villazzano (TN) Italy department of Theoretical Physics and IFIc University of Valencia and CSIC E-46100 Valencia Spain

We present a pedagogical overview of the nonperturbative mechanism that endows gluons with a dynamical mass. This analysis is performed based on pure Yang-Mills theories in the Landau gauge, within the theoretical framework that emerges from the combination of the pinch technique with the background field method. In particular, we concentrate on the Schwinger-dyson equation satisfied by the gluon propagator and examine the necessary conditions for obtaining finite solutions within the infrared region. The role of seagull diagrams receives particular attention, as do the identities that enforce the cancellation of all potential quadratic divergences. We stress the necessity of introducing nonperturbative massless poles in the fully dressed vertices of the theory in order to trigger the Schwinger mechanism, and explain in detail the instrumental role of these poles in maintaining the Becchi-Rouet-Stora-Tyutin symmetry at every step of the mass-generating procedure. The dynamical equation governing the evolution of the gluon mass is derived, and its solutions are determined numerically following implementation of a set of simplifying assumptions. The obtained mass function is positive definite, and exhibits a power law running that is consistent with general arguments based on the operator product expansion in the ultraviolet region. A possible connection between confinement and the presence of an inflection point in the gluon propagator is briefly discussed.

关键词： nonperturbative physics Schwinger-dyson equations dynamical mass generation

Evolution-aided engineering of plant specialized metabolism

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aBIOTEcH 2021年第3期2卷 240-263页

作者： Mohammad Irfan Benjamin chavez Paride Rizzo John c.d'Auria Gaurav d.Moghe Plant Biology Section School of Integrative Plant ScienceCornell UniversityIthacaNYUSA Metabolic diversity Group Leibniz Institute of Plant Genetics and Crop Plant Research(IPK)06466 SeelandGermany

The evolution of new traits in living organisms occurs via the processes of mutation,recombination,genetic drift,and *** processes that have resulted in the immense biol ogical diversity on our planet are also being employed in metabolic engineering to optimize enzymes and pathways,create new-to-nature reactions,and synthesize complex natural products in heterologous *** this review,we discuss two evolution-aided strategies for metabolic engineering-directed evolution,which improves upon existing genetic templates using the evolutionary process,and combinatorial pathway reconstruction,which brings together genes evolved in different organisms into a single heterol ogous *** discuss the general principles of these strategies,describe the technologies involved and the molecular traits they influence,provide examples of their use,and discuss the roadblocks that need to be addressed for their wider adoption.A better understanding of these strategies can provide an impetus to research on gene function discovery and biochemical evolution,which is foundational for improved metabolic *** evolution-aided approaches thus have a substantial potential for improving our understanding of plant metabolism in general,for enhancing the production of plant metabolites,and in sustainable agriculture.

关键词： Evolution Metabolic engineering Plant biotechnology Synthetic biology

Use and application of cFc-11,cFc-12,cFc-113 and SF6 as environmental tracers of groundwater residence time:A review

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Geoscience Frontiers 2019年第5期10卷 1643-1652页

作者： L.A. chambers d.c. Gooddy A.M. Binley department of civil and Environmental Engineering University of StrathclydeGlasgowG1 1XJUK Lancaster Environment centre Lancaster UniversityLancasterLA1 4YQUK British Geological Survey Maclean BuildingWallingfordOX10 8BBUK

Groundwater residence time is a fundamental property of groundwater to understand important hydrogeological issues,such as deriving sustainable abstraction volumes,or,the evolution of groundwater *** anthropogenic trace gases chlorofluorocarbons (cFc-11,cFc-12 and cFc-113) and sulphur hexafluoride (SF6) are ideal in this regard because they have been released globally at known rates and become dissolved in groundwater following Henry’s Law,integrating over large spatial (global) and temporal (decades) *** cFcs and SF6 are able to date groundwater up to w100 years old with the caveat of certain simplifying ***,the inversion of environmental tracer concentrations (cFcs and SF6) to derive groundwater age rests on the accurate determination of groundwater recharge parameters,namely temperature,elevation,salinity and excess air,in addition to resolving the potential for contamination,degradation and unsaturated zone *** review explores the fundamentals of cFc-11,cFc-12,cFc-113 and SF6 as environmental tracers of groundwater age and recommends complementary techniques *** this relatively simple and inexpensive technique has been used to determine initial concentrations at the recharge zone,setting the groundwater dating ‘clock’ to zero,this review then explores the meaning of groundwater ‘age’ in relation to measured environmental tracer *** is shown that the cFcs and SF6 may be applied to a wide-range of hydrogeological problems and suggests that environmental tracers are particularly powerful tools when integrated with numerical flow and transport models.

关键词： Hydrogeology Environmental tracers Groundwater dating

Luminescence properties of dysprosium doped YVO_4 phosphor

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Journal of Rare Earths 2018年第12期36卷 1245-1249页

作者： H.J.Rajendra c.PANdurangappa d.L.Monika department of Physics RNS Institute of TechnologyChannasandra department of Physics SJB Institute of Technology

Trivalent dysprosium(dy) activated nanocrystalline yttrium vanadate(YVO) phosphor was synthesized via co-precipitation method. The prepared samples were characterized by X-ray diffraction(XRd),Fourier transform infrared spectroscopy(FTIR), scanning electron microscopy(SEM), optical absorption and photo luminescence(PL) techniques. The XRd patterns reveal the tetragonal crystalline phase. SEM images reveal that dy doped YVOnanocrystals are agglomerated. EdAX confirms the formation of YVO:dy. FTIR spectrum shows two strong absorption bands at 459 and 761 cm. Optical absorption spectrum showed the surface defects in the as-prepared samples. The PL emission spectrum shows two characteristic emission bands at 485 and 575 nm. The strong yellow emission peak at 575 nm is assigned to ~4 F→~6 Hhyper sensitive transition of dyions, Study of cIE chromaticity diagram indicates the suitability of the phosphor for the development of yellow-green LEds.

关键词： Precipitation Yttrium vanadate dysprosium X-ray diffraction Photoluminescence Rare earths

Multiplication factor for open ground storey buildings–a reliability based evaluation

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Earthquake Engineering and Engineering Vibration 2016年第2期15卷 283-295页

作者： Haran Pragalath d.c Avadhoot Bhosale Robin davis P Pradip Sarkar department of civil Engineering NIT Rourkela

Open Ground Storey（OGS） framed buildings where the ground storey is kept open without infill walls, mainly to facilitate parking, is increasing commonly in urban areas. However, vulnerability of this type of buildings has been exposed in past earthquakes. OGS buildings are conventionally designed by a bare frame analysis that ignores the stiffness of the infill walls present in the upper storeys, but doing so underestimates the inter-storey drift（ISd） and thereby the force demand in the ground storey columns. Therefore, a multiplication factor（MF） is introduced in various international codes to estimate the design forces（bending moments and shear forces） in the ground storey columns. This study focuses on the seismic performance of typical OGS buildings designed by means of MFs. The probabilistic seismic demand models, fragility curves, reliability and cost indices for various frame models including bare frames and fully infilled frames are developed. It is found that the MF scheme suggested by the Israel code is better than other international codes in terms of reliability and cost.

关键词： frames probabilistic vulnerability facilitate details Probability codes multiplication drift columns

Bifurcation of rupture path by nonlinear damping force

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Applied Mathematics and Mechanics(English Edition) 2011年第3期32卷 285-292页

作者： A. A. ZAINAL c. c. d. LING S. Y. FAISAL department Mathematics Faculty ScienceUniversiti Teknologi MalaysiaSkudai 81310JohorMalaysia

The linear damping mechanism of the Rayleigh waves is extended to the nonlinear one. conferring to the model, the analytical method is chosen for the solutions. These solutions depict the unusual bifurcation of the ru... 详细信息

关键词： bifurcation of rupture path antisoliton soliton

Variable Energy Positron Annihilation Spectroscopy of GaN Grown on Sapphire Substrates with MOcVd

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chinese Physics Letters 2005年第5期22卷 1214-1217页

作者：胡一帆 c.d.Beling S.Fung departmentofPhysics HuazhongUniversityofScienceandTechnologyWuhan430074 departmentofPhysics UniversityofHongKongPokfulamRoadHongKong

depth profiled doppler broadening of positron annihilation spectroscopy (dBPAS), which is also called the variable energy positron annihilation spectroscopy (VEPAS), is used in characterization of GaN grown on sapphire substrates with metal-organic chemical vapour deposition (MOcVd). The GaN film and the film/substrate interface are investigated. The VEPFIT (variable energy positron fit) software was used for analysing the data, and the positron diffusion length of the sapphire is obtained. The results suggest that there is a highly defected region near the GaN/sapphire interface. This thin dislocated region is generated at the film/substrate interface to relieve the strain. Effects of implantation dose on defect formation, for the GaN/Sapphire samples, which implanted by Al+ ions, are also investigated. Studies on Al+ implanted GaN films (not including the interface and sapphire) have revealed that there are two different regions of implantation damage. For the low Al+ implantation dose samples, in the region close to the surface, defects are mainly composed of vacancy pairs with small amount of vacancy clusters, and in the interior region of the film the positron traps are vacancy clusters without micro-voids. For the highest dose sample, however, some positron trap centres are in the form of micro-voids in the second region.

关键词： Sapphire

Photo-induced Synthesis and characterization of Poly(methyl methacrylate) Grafted Sodium Salt of Partially carboxymethylated Guar Gum

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chinese Journal of Polymer Science 2014年第12期32卷 1690-1703页

作者： J.H.Trivedi M.d.Thaker H.c.Trivedi P.G. department of chemistry Sardar Patel University

Photo-induced graft copolymerization of methyl methacrylate（MMA） onto sodium salt of partially carboxymethylated guar gum（Na-PcMGG, dS = 0.291） was carried out in an aqueous medium using ceric ammonium nitrate（cAN） as photoinitiator to synthesize a novel graft copolymer, Na-PcMGG-g-PMMA, which may find its potential application as a metal adsorbent. The influences of synthesis variables such as concentrations of photoinitiator（cAN）, nitric acid and monomer（MMA） as well as reaction time, temperature and amount of substrate on the grafting yields were studied and the reaction conditions for optimum photo-grafting were evaluated. At optimum concentration, the maximum values of the grafting yields achieved were G = 271.61% and GE = 63.89%. The experimental results were found to be in very good agreement with the proposed kinetic scheme. The photo-graft copolymerization of MMA onto Na-PcMGG（ dS = 0.291） was also carried out in the presence and absence of ultraviolet radiation for studying the efficiency of the photoinitiator. The influence of carboxymethyl groups introduced onto the guar gum molecules with regard to its behavior towards ultra-violet radiation induced grafting with MMA was also investigated. Photo-grafting process was confirmed and the products were characterized with the help of the spectroscopic（1H-NMR and FTIR） and SEM techniques.

关键词： Photo-induced grafting Methyl methacrylate Sodium salt of partially carboxymethylated guar gum Optimum reaction conditions characterization.

Biomarkers of end of shift exposure to disinfection byproducts in nurses

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Journal of Environmental Sciences 2017年第8期29卷 217-223页

作者： Solomon Ioannou Xanthi d.Andrianou Pantelis charisiadis Konstantinos c.Makris cyprus International Institute for Environmental and Public Health Cyprus University of Technology Limassol 3041 Cyprus

Increased disinfectant use commonly takes place in hospitals and other health care settings. A cross-sectional study among active nurses in two cypriot public hospitals（n = 179） was conducted to examine the prevalence of exposure to disinfection byproducts（dBPs）, such as trihalomethanes（THMs） using both self-reported information and biomarker *** objectives of this study were to： i） quantify the magnitude and variability of occupational exposure to disinfectants/dBPs in nurses, ii） generate job exposure matrices（JEM） and job task exposure matrices（JTEM） for disinfectants, and iii） assess the major determinants of urinary THMs in nurses. End of shift urinary total THM values showed high variability among the nurses, but did not differ between hospitals. The disinfectant group of alcohols/phenols was used by 〉 98% of nurses, followed by octenidine（82%）, iodine and chlorine（39%, each）,chlorhexidine（25%）, formaldehyde（12%）, hydrogen peroxide（11%）, and peracetic acid/ammonia/quaternary ammonium compounds（QAcs）, all being 〈 8% each. chlorine use during the past 24 hr was associated with significantly（p 〈 0.05） lower brominated THMs（Br THMs） after adjusting for age, gender and BMI, while a positive association was shown for TcM and the sum of all THMs（TTHMs）, albeit not significant. Nurses were exposed to nearly double the levels of TTHMs and BrT HMs（median and IQR, 1027 [560, 2475] ng/g and 323 [212,497] ng/g, respectively） when compared to those of the general population（552 [309,989] ng/g and 152 [87,261] ng/g, respectively）. This was the first occupational health dataset reporting measurements of biomarkers of end of shift exposures to disinfectants/dBPs.

关键词： Nurses disinfectants disinfection Exposure Biomarker Job exposure matrix Healthcare