Investigation of high-K gate dielectrics for advanced CMOS application

Ph.DDOCTOR OF PHILOSOPH

Regional analysis of potential polychlorinated biphenyl degrading bacterial strains from China

AbstractPolychlorinated biphenyls (PCBs), the chlorinated derivatives of biphenyl, are one of the most prevalent, highly toxic and persistent groups of contaminants in the environment. The objective of this study was to investigate the biodegradation of PCBs in northeastern (Heilongjiang Province), northern (Shanxi Province) and eastern China (Shanghai municipality). From these areas, nine soil samples were screened for PCB-degrading bacteria using a functional complementarity method. The genomic 16S rDNA locus was amplified and the products were sequenced to identify the bacterial genera. Seven Pseudomonas strains were selected to compare the capacity of bacteria from different regions to degrade biphenyl by HPLC. Compared to the biphenyl content in controls of 100%, the biphenyl content went down to 3.7% for strain P9-324, 36.3% for P2-11, and 20.0% for the other five strains. These results indicate that a longer processing time led to more degradation of biphenyl. PCB-degrading bacterial strains are distributed differently in different regions of China

Randomized and efficient time synchronization in dynamic wireless sensor networks: a gossip-consensus-based approach

This paper proposes novel randomized gossip-consensus-based sync (RGCS) algorithms to realize efficient time correction in dynamic wireless sensor networks (WSNs). First, the unreliable links are described by stochastic connections, reflecting the characteristic of changing connectivity gleaned from dynamicWSNs. Secondly, based on the mutual drift estimation, each pair of activated nodes fully adjusts clock rate and offset to achieve network-wide time synchronization by drawing upon the gossip consensus approach. The converge-to-max criterion is introduced to achieve a much faster convergence speed. The theoretical results on the probabilistic synchronization performance of the RGCS are presented. Thirdly, a Revised-RGCS is developed to counteract the negative impact of bounded delays, because the uncertain delays are always present in practice and would lead to a large deterioration of algorithm performances. Finally, extensive simulations are performed on the MATLAB and OMNeT++ platform for performance evaluation. Simulation results demonstrate that the proposed algorithms are not only efficient for synchronization issues required for dynamic topology changes but also give a better performance in term of converging speed, collision rate, and the robustness of resisting delay, and outperform other existing protocols

Investigation and analysis of an outbreak of foodborne disease caused by Salmonella enteritidis in a district of Chongqing

ObjectiveTo provide the basis for dealing with similar incidents in the future， an outbreak of foodborne illness caused by the consumption of bread contaminated with Salmonella enteritidis was investigated.MethodsDescriptive epidemiological methods were used to analyze the clinical characteristics， epidemiological distribution and related risk factors of the cases. The etiological food was determined by retrospective cohort study. The biological samples， food remains and environmental samples of the cases and canteen employees were detected by laboratory testing. The causes of the outbreak were comprehensively analyzed based on the results of epidemiological investigation， laboratory tests and sanitary investigation.ResultsRetrospective cohort study showed that a batch of pre-packaged bread produced by a food factory in Chongqing on May 20， 2021 was the suspicious food. A total of 73 people ate the suspicious bread in this incident， and 55 of them got ill with a morbidity rate of 75.34% and a median incubation period of 15 h. At the same time， Salmonella enteritidis was detected in food remains， related environmental samples and anal swabs of patients.ConclusionThe incident was an outbreak of foodborne disease caused by bread contaminated with Salmonella enteritidis

Mechanical Behavior and Application of a Novel Supporting and Retaining Structure for Slope

This paper proposed a novel supporting and retaining structure used to high-steep building slope reinforcement. It combined with an anti-sliding pile and an inclined supporting column, which is used as a fulcrum on the upper part of pile. The mechanical characteristics of the novel supporting and retaining structure are studied firstly by two mechanical methods and two numerical methods, respectively. Result shows that the axial force will be evenly distributed along the column body and it provide a quite resistant force, meanwhile. There are two shear force concentrated areas of the anti-sliding pile, one is from the top of the embedded area of the pile body to the potential slip plane, the other is at the joint. Subsequently, the results of these methods are compared synthetically and the differences between the results are also discussed. It shows that a large shear force and moment will be caused at the restrained end of the pile body by the force method and 2D numerical model 1. And in Wenkler model and the 2D numerical model 2, the rock is considered non-rigid, the anti-sliding pile will produce a certain amount of deflection under the sliding thrust, which reduces the shear force and moment at the top of the embedded area of the pile body. Finally, the novel supporting and retaining structure is applied to the site, and the monitoring data shows that the novel supporting and retaining structure is economic and effective for the reinforcement of the high-steep building slope

Co-estimation of state-of-charge and state-of-health for high-capacity lithium-ion batteries.

To address the challenges of efficient state monitoring of lithium-ion batteries in electric vehicles, a co-estimation algorithm of state-of-charge (SOC) and state-of-health (SOH) is developed. The algorithm integrates techniques of adaptive recursive least squares and dual adaptive extended Kalman filtering to enhance robustness, mitigate data saturation, and reduce the impact of colored noise. At 25C, the algorithm is tested and verified under dynamic stress test (DST) and Beijing bus DST conditions. Under the Beijing bus DST condition, the algorithm achieves a mean absolute error (MAE) of 0.17% and a root mean square error (RMSE) of 0.19% for SOC estimation, with a convergence time of 4 s. Under the DST condition, the corresponding values are 0.05% for MAE, 0.07% for RMSE, and 5 s for convergence time. Moreover, in this research, the SOH is described as having internal resistance. Under the Beijing bus DST condition, the MAE and the RMSE of the estimated internal resistance of the proposed approach are 0.018% and 0.075%, with the corresponding values of 0.014% and 0.043% under the DST condition. The results of the experiments provide empirical evidence for the challenges associated with the efficacious estimation of SOC and SOH