Impact of Exchange-Correlation Effects on the IV Characteristics of a Molecular Junction

The role of exchange-correlation effects in non-equilibrium quantum transport through molecular junctions is assessed by analyzing the IV curve of a generic two-level model using self-consistent many-body perturbation theory (second Born and GW approximations) on the Keldysh contour. For weak molecule-lead coupling we identify a mechanism which can lead to anomalously strong peaks in the dI/dV due to a bias-induced interplay between the position of the HOMO and LUMO levels. The effect is suppressed by self-interaction errors and is therefore unlikely to be observed in standard transport calculations based on density functional theory. Inclusion of dynamic correlations lead to substantial renormalization of the energy levels. In particular, we find a strong enhancement of quasi-particle (QP) scattering at finite bias which reduces the QP lifetimes significantly with a large impact on the IV curve.Comment: 4 pages, 3 figures. Phys. Rev. Lett. (accepted

Effect of Oxygen and Nitrogen Sparging during Grape Fermentation on Volatile Sulphur Compounds

Elemental sulphur is a common fungicide applied in vineyards before harvest, and has been found toincrease the production of desirable polyfunctional mercaptans, but also H2S and unwanted reductivesulphur aroma compounds. This paper investigates the effectiveness of oxygen and nitrogen sparging,applied during fermentation, on the removal of volatile sulphur compounds in Sauvignon blanc wines.Increasing the amount of elemental sulphur added to grapes after pressing, from nil to 10 to 100 mg/L,led to an increase in the formation of 3-mercaptohexanol (3MH), of 3-mercaptohexyl acetate (3MHA) forthe 10 mg/L additions only, and of some unwanted reductive compounds. Few changes were observed inthe concentrations of aroma compounds when the juices were sparged with nitrogen during fermentation.Additions of oxygen during fermentation led to some decrease in the concentration of polyfunctionalmercaptans for the 10 mg/L sulphur additions, but did not significantly remove reductive aroma compounds.Few differences were observed in the concentration of wine phenolics or of further wine aroma familieswith any of the treatments

The Role of Federated Learning in a Wireless World with Foundation Models

Foundation models (FMs) are general-purpose artificial intelligence (AI) models that have recently enabled multiple brand-new generative AI applications. The rapid advances in FMs serve as an important contextual backdrop for the vision of next-generation wireless networks, where federated learning (FL) is a key enabler of distributed network intelligence. Currently, the exploration of the interplay between FMs and FL is still in its nascent stage. Naturally, FMs are capable of boosting the performance of FL, and FL could also leverage decentralized data and computing resources to assist in the training of FMs. However, the exceptionally high requirements that FMs have for computing resources, storage, and communication overhead would pose critical challenges to FL-enabled wireless networks. In this article, we explore the extent to which FMs are suitable for FL over wireless networks, including a broad overview of research challenges and opportunities. In particular, we discuss multiple new paradigms for realizing future intelligent networks that integrate FMs and FL. We also consolidate several broad research directions associated with these paradigms.Comment: 8 pages, 5 figures, 1 tabl

A Case Report of Puffer Fish Poisoning in Singapore

Although many Asians regard puffer fish as a delicacy since ancient times, puffer fish (Lageocephalus scitalleratus) is also a well-known source of possibly lethal food poisoning. The fish is gaining popularity in Singapore and can be found in quite a few restaurants now. Puffer fish contains tetrodotoxin (TTX), a potent poison affecting the neural pathway. Puffer fish poisoning may cause a constellation of symptoms, such as giddiness, numbness and tingling sensation of the mouth, paresthesia, and muscle weakness. Severe cases may present with respiratory depression, circulatory failure, and death. TTX poisonings have been reported in Japan, Taiwan, Hong Kong, Bangladesh, and the United States (Haque et al. 2008). We report a case of mild poisoning and suggest observation for such cases

An objective based classification of aggregation techniques for wireless sensor networks

Wireless Sensor Networks have gained immense popularity in recent years due to their ever increasing capabilities and wide range of critical applications. A huge body of research efforts has been dedicated to find ways to utilize limited resources of these sensor nodes in an efficient manner. One of the common ways to minimize energy consumption has been aggregation of input data. We note that every aggregation technique has an improvement objective to achieve with respect to the output it produces. Each technique is designed to achieve some target e.g. reduce data size, minimize transmission energy, enhance accuracy etc. This paper presents a comprehensive survey of aggregation techniques that can be used in distributed manner to improve lifetime and energy conservation of wireless sensor networks. Main contribution of this work is proposal of a novel classification of such techniques based on the type of improvement they offer when applied to WSNs. Due to the existence of a myriad of definitions of aggregation, we first review the meaning of term aggregation that can be applied to WSN. The concept is then associated with the proposed classes. Each class of techniques is divided into a number of subclasses and a brief literature review of related work in WSN for each of these is also presented

Highly Conducting pi-Conjugated Molecular Junctions Covalently Bonded to Gold Electrodes

We measure electronic conductance through single conjugated molecules bonded to Au metal electrodes with direct Au-C covalent bonds using the scanning tunneling microscope based break-junction technique. We start with molecules terminated with trimethyltin end groups that cleave off in situ resulting in formation of a direct covalent sigma bond between the carbon backbone and the gold metal electrodes. The molecular carbon backbone used in this study consist of a conjugated pi-system that has one terminal methylene group on each end, which bonds to the electrodes, achieving large electronic coupling of the electrodes to the pi-system. The junctions formed with the prototypical example of 1,4-dimethylenebenzene show a conductance approaching one conductance quantum (G0 = 2e2/h). Junctions formed with methylene terminated oligophenyls with two to four phenyl units show a hundred-fold increase in conductance compared with junctions formed with amine-linked oligophenyls. The conduction mechanism for these longer oligophenyls is tunneling as they exhibit an exponential dependence of conductance with oligomer length. In addition, density functional theory based calculations for the Au-xylylene-Au junction show near-resonant transmission with a cross-over to tunneling for the longer oligomers.Comment: Accepted to the Journal of the American Chemical Society as a Communication

Analog IC test and product engineering curriculum for Malaysia microelectronics industry

Production test is a significant driver of semiconductor manufacturing cost. Parallel with the advances of semiconductor fabrication, the need for a pool of talented product and test engineers is significantly increasing. This paper describes the academia-industries collaboration effort in developing an analogue electronic test and product engineering to boost-up technical competencies of electronic engineering graduates particularly in microelectronic major. The program has been successfully conducted at Universiti Putra Malaysia with strong support from Texas Instruments and Teradyne

The Role of Ultrasound in teaching Clinical Anatomy to First year Medical Students

Abstract Introduction: Undergraduate medical education training has recently shifted towards making content relevant and applicable for future clinical practice. However, students often encounter difficulties in visualizing the functional living human and apply clinically relevant anatomy content. Hence, the aim of this study is to evaluate the role and efficacy of ultrasound in teaching clinical anatomy to first year medical students

Strong polarization-induced reduction of addition energies in single-molecule nanojunctions

We address polarization-induced renormalization of molecular levels in solid-state based single-molecule transistors and focus on an organic conjugate molecule where a surprisingly large reduction of the addition energy has been observed. We have developed a scheme that combines a self-consistent solution of a quantum chemical calculation with a realistic description of the screening environment. Our results indeed show a large reduction, and we explain this to be a consequence of both (a) a reduction of the electrostatic molecular charging energy and (b) polarization induced level shifts of the HOMO and LUMO levels. Finally, we calculate the charge stability diagram and explain at a qualitative level general features observed experimentally.Comment: 9 pages, 5 figure

Correlation of interfacial bonding mechanism and equilibrium conductance of molecular junctions

We report theoretical investigations on the role of interfacial bonding mechanism and its resulting structures to quantum transport in molecular wires. Two bonding mechanisms for the Au-S bond in an Au(111)/1,4-benzenedithiol(BDT)/Au(111) junction were identified by ab initio calculation, confirmed by a recent experiment, which, we showed, critically control charge conduction. It was found, for Au/ BDT/Au junctions, the hydrogen atom, bound by a dative bond to the Sulfur, is energetically non-dissociative after the interface formation. The calculated conductance and junction breakdown forces of H-non-dissociative Au/BDT/Au devices are consistent with the experimental values, while the H-dissociated devices, with the interface governed by typical covalent bonding, give conductance more than an order of magnitude larger. By examining the scattering states that traverse the junctions, we have revealed that mechanical and electric properties of a junction have strong correlation with the bonding configuration. This work clearly demonstrates that the interfacial details, rather than previously believed many-body effects, is of vital importance for correctly predicting equilibrium conductance of molecular junctions; and manifests that the interfacial contact must be carefully understood for investigating quantum transport properties of molecular nanoelectronics.Comment: 18 pages, 6 figures, 2 tables, to be appeared in Frontiers of Physics 9(6), 780 (2014