Influences of mechanically and dielectrically imperfect interfaces on the reflection and transmission waves between two piezoelectric half spaces

The influences of mechanically and dielectrically imperfect interfaces on the reflection and transmission waves between two piezoelectric half spaces are studied in this paper. First, the secular equations in the traverse isotropic piezoelectric half space are derived from the general dynamic equation. Then, six kinds of imperfect interfaces are considered. These imperfect interfaces include: the mechanically compliant, dielectrically weakly conducting imperfect interface; the mechanically compliant, dielectrically highly conducting imperfect interface; the grounded metallized interface and the low-dielectric interface and their mechanical counterpart, namely, the fixed interface and the slippery interface. These imperfect interface conditions are required to be satisfied by four sets of waves, namely, the quasi-longitudinal wave (QP), the quasi-transverse wave (QSV), the shear horizontal wave (SH) which is decoupled to other waves and the electric-acoustic wave (EA). The algebraic equations resulting from the imperfect interface conditions are solved to obtain the amplitude ratio of various waves and furthermore the reflection and transmission coefficients in terms of the energy flux ratio. The numerical results are obtained for the incident QP wave, the incident QSV wave and the incident SH wave and are validated by the energy conservation principle. The effects of these imperfect interfaces are discussed based on the numerical results. The present study provides useful information for the detection of imperfect interface. (C) 2015 Elsevier Ltd. All rights reserved

Contribution of exopeptidases to formation of nonprotein nitrogen during ensiling of alfalfa

The experiment was conducted to investigate the exopeptidase classes in alfalfa (Medicago sativa L.) leaves, and to determine their contribution to the formation of nonprotein nitrogen (NPN) components during ensiling. Six classes of inhibitors that included bestatin (aminopeptidase inhibitor), potato carboxypeptidase inhibitor (PCI, carboxypeptidase inhibitor), 1,10-phenanthroline (dipeptidase inhibitor), diprotin A (dipeptidyl-peptidase inhibitor), butabindide (tripeptidyl-peptidase inhibitor), and dipeptide Phe-Arg (peptidyl-dipeptidase inhibitor) were used. To determine the contribution of each exopeptidase to the formation of NPN products, aqueous extracts of fresh alfalfa were fermented to imitate the proteolytic process of ensiled alfalfa and to ensure that each class of exopeptidase inhibitor would have immediate contact with the proteases in the alfalfa extract. Five classes of exopeptidases; namely, aminopeptidase, carboxypeptidase, dipeptidase, dipeptidyl-peptidase, and tripeptidyl-peptidase, were shown to be present in alfalfa leaves, each playing a different role in alfalfa protein degradation. Aminopeptidase, carboxypeptidase, and dipeptidase were the main exopeptidases contributing to the formation of NH3-N. Among the 5 exopeptidases, tripeptidyl-peptidase appeared to be the principal exopeptidase in hydrolyzing forage protein into peptides, whereas carboxypeptidase and dipeptidase appeared to be more important in contributing to the formation of amino acid-N. Dipeptidyl-peptidase and tripeptidyl-peptidase did not play a role in the formation of NH3-N or amino acid-N. Dipeptidase, carboxypeptidase, and tripeptidyl-peptidase were the principal exopeptidases for hydrolyzing forage protein into NPN during ensilage, and treatment with a mixture of the 5 inhibitors reduced the total NPN concentration in the fermented alfalfa extract to about 45% of that in the control after 21 d of fermentation

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

Marconiplein New Transportation Hub

We are in a digital era , the development of technology will affect the architecture to a large extent , from design to construction, from management to using, everything would be changed. From this perspective, my project and its approach can be considered as a product that is generated by the digital social context.HyperbodyArchitectureArchitecture and The Built Environmen

Investigation on Capacitive Sensor Interface with Improved Immunity to External Interference

This thesis presents the results of the undertaken investigation on industrial capacitance sensor interface for measuring small displacements, with focus on immunity to external interference, especially when using long cables. Several principles have been investigated and comparison has been made, followed by the proposed measurement principle, which can be implemented without electrical contact with the target. The range of measurement is up to 10 pF. Such sensor interface is designed to tolerate up to a 10-meter cable, and more importantly, due to the special measurement principle, such system is designed to have an improved immunity to external interferences. There are several advantages of such a system, compared with existing capacitive sensor interfaces: (i) the special sensor configuration minimizes external interference (mostly electromagnetic interference); (ii) the measurement principle makes the front-end amplifier less sensitive to non-idealities like offset; (iii) a switch-capacitor type active shielding technique reduces the effect of cable capacitance. The results so far show that the dynamic range of such interface can reach more than 12 bits, with a measurement time less than 100 us.Microelectronics & Computer EngineeringElectrical Engineering, Mathematics and Computer Scienc

Dissolution and Electrochemical Reduction of Rare Earth Oxides in Fluoride Electrolytes

Rare earth elements (REEs) are a group of 17 metallic elements, including 15 lanthanides, scandium and yttrium, which have remarkably similar chemical and physical properties. Nowadays, rare earth metals are widely used in such fields as electronics, petroleum, and metallurgy. Rare earth elements are considered as vitamin to modern industry and critical resources to many countries.Neodymium is a light lanthanide, and its demand has been substantially boosted due to the broad application of NdFeB permanent magnets in electronics and new energy industries.Oxide-fluoride electrolysis is the main commercial method to produce rare earth metals and their alloys, especially light lanthanides, in both primary and secondary production. The oxide-fluoride electrolysis process involves first the dissolution of rare earth oxide(s) (REO(s)) in a molten fluoride, which serves as both a solvent and an electrolyte. During an electrochemical process, rare earth cations are reduced at the cathode and the respective metal is formed. Even though this method was adopted from laboratory to industrial production about 50 years ago, the exact mechanism of the process is not fully clarified. A deeper understanding of the process from both physicochemical and electrochemical points of view is crucial for process optimization, improving its current efficiency and power consumption. Maintaining enough REOs in the electrolyte and having a fast dissolution are crucial factors for good industrial practice. Identifying the electrochemical reactions involved during the electrolysis is vitally important for promoting target reactions and restricting side reactions, which are linked directly to the economic indicators of the process.Therefore, this thesis focuses on the solubility of REOs in molten fluorides, developing a semi-empirical model for the estimation of REO solubility, dissolution behavior of Nd2O3 in molten fluoride, and electrochemical behavior of Nd(III) in fluoride melt.Team Yongxiang Yan

Campus for City / City for Campus

Connecting, among university campuses & between campuses and the city of Shanghai.MscUrbanismArchitectur

A CAST-Based Analysis of the Metro Accident That Was Triggered by the Zhengzhou Heavy Rainstorm Disaster

Emergency management research is used to deal with the increasing number of extreme weather threats in urban areas. This paper uses causal analysis based on systems theory (CAST) to review the subway water ingress accident and the government's emergency management actions in Zhengzhou, Henan Province, during the heavy rainstorm disaster on 20 July 2021. The aims of this article are to establish safety control structures at both the enterprise level and the government level, and to systematically analyze the problems in emergency management in Zhengzhou City. Our analysis found that the construction of disaster prevention facilities restricted emergency management. Therefore, we suggest that enterprises and governments not only pay attention to emergency management, but also to the construction of disaster prevention facilities. This article also points out that the system of chief executive responsibility that is implemented in China is becoming a double-edged sword in emergency management. Our study makes recommendations for enhancing the capacities of emergency management, points out the shortcomings of the existing emergency management structure, and provides knowledge gained for future emergency management research.Safety and Security Scienc

Active-feedback quantum control of an integrated low-frequency mechanical resonator

Preparing a massive mechanical resonator in a state with quantum limited motional energy provides a promising platform for studying fundamental physics with macroscopic systems and allows to realize a variety of applications, including precise sensing. While several demonstrations of such ground-state cooled systems have been achieved, in particular in sideband-resolved cavity optomechanics, for many systems overcoming the heating from the thermal bath remains a major challenge. In contrast, optomechanical systems in the sideband-unresolved limit are much easier to realize due to the relaxed requirements on their optical properties, and the possibility to use a feedback control schemes to reduce the motional energy. The achievable thermal occupation is ultimately limited by the correlation between the measurement precision and the back-action from the measurement. Here, we demonstrate measurement-based feedback cooling on a fully integrated optomechanical device fabricated using a pick-and-place method, operating in the deep sideband-unresolved limit. With the large optomechanical interaction and a low thermal decoherence rate, we achieve a minimal average phonon occupation of 0.76 when pre-cooled with liquid helium and 3.5 with liquid nitrogen. Significant sideband asymmetry for both bath temperatures verifies the quantum character of the mechanical motion. Our method and device are ideally suited for sensing applications directly operating at the quantum limit, greatly simplifying the operation of an optomechanical system in this regime.QN/Groeblacher La

Many-objective optimization with improved shuffled frog leaping algorithm for inter-basin water transfers

Inter-basin water transfers (IBWT) are implemented to re-allocate unevenly distributed water resources. However, many conflicting objectives associated with society, economy, and environment have made the water resources allocation problem in IBWT more complicated than ever before. Thus, there is a continuous need for in-depth research with the latest optimization techniques to secure many-objective allocation of water resources for IBWT. In addition, being troubled of easily falling into local minima and premature convergence in some multi-objective optimization algorithms, it is necessary to explore new alternatives to improve their search quality. Here we propose a many-objective optimization methodology for IBWT, which includes three modules: (1) formulating a many-objective optimization problem based on realistic controls; (2) developing a new multi-objective real-coded quantum inspired shuffled frog leaping algorithm (r-MQSFLA) to solve the optimization problem; (3) utilizing the Analytic Hierarchy Process (AHP)-Entropy method to filter the Pareto solutions. In r-MQSFLA, the real-coded quantum computer and the external archive with dynamic updating mechanism are applied to SFLA. The performance of r-MQSFLA is first compared to that of other multi-objective evolutionary algorithms (MOEAs) in solving mathematical benchmark problems. A case study of the Eastern Route of South-to-North Water Transfer Project in Jiangsu Province, China varying from a normal to an extremely dry year, demonstrates that r-MQSFLA displays approximate performance on some compared algorithms and is improved significantly than MOSFLA in terms of convergence, diversity and reasonable solutions. This study can update the understanding of quantum theory to MOEAs and will provide a reference for better water resources allocation in IBWT under uncertainty.Water Resource