CONSTRUCTING HYBRID NANOSTRUCTURES OUT OF NOBLE METALS AND SEMICONDUCTORS

Fabrication of complex hybrid nanostructures with tunable properties is desirable to fulfill functional applications in multidisciplinary areas. Manipulation of pre-designed nanostructure building blocks composed of distinct materials to achieve finite control over crystallinity, morphology, and composition is a major challenge. This dissertation aims to address the topic and create material with new optical properties. Questions explored are: How to realize delicate control on crystallinity of hybrid nanostructures through unconventional synthetic routes? How to achieve precise hybridized nanostructures with designed geometry, topology and composition? How do these features affect optical properties? Specifically, this dissertation contains recent efforts on fabrication and characterization of functional hybrid nanostructures made from metal and semiconducting materials. I first present a critical review of a monocrystalline nonepitaxially grown metallic @ semiconducting core @ shell hybrid nanostructures. This includes a comprehensive description of the novel nonepitaxial synthetic route, emphasizing critical experimental steps, anticipation of challenges, and ending with my perspective. This systematic review should expand knowledge of the newly developed nonepitaxial method and spread technical aspects of the experiments. I then introduce an anisotropically shaped semiconducting nanocrystal with binary alloy composition. The rod-shaped ensemble has exhibited tunable bright band gap fluorescence that is dependent on dimension. This work is the first to achieve binary semiconducting alloy nanocrystals with anisotropic shapes. Interestingly, the electronic behavior within the rod-shaped semiconducting nanocrystals is altered due to gradient element distribution of the binary material, which is of fundamental interest and potential practical importance. Lastly, a core – metallic satellites-styled nanoparticle assembly structure will be discussed. Control over Ag nanoparticles as surrounding satellites in terms of size, shape and quantity is achieved via a facile synthetic route, and a collective electronic (dipole – dipole coupling) behavior within the metallic assembly is observed, and supported by numerical simulation. This work provides a new facile pathway to achieve well-controlled silica – Ag hybrid nanostructures

Bridging childhood to adulthood: the impact of early life stress on acute stress responses

BackgroundChildhood trauma exerts enduring impacts on the physical and psychological well-being of individuals in adulthood, influencing their daily functioning. This study aims to investigate the impact of childhood trauma on stress recovery in adults, concentrating on heart rate variations during acute stress exposure.MethodsA cohort of 126 participants completed the Childhood Trauma Questionnaire (CTQ) and underwent the Trier Social Stress Test (TSST) to elicit acute stress, with continuous heart rate (HR) monitoring for stress recovery assessment.ResultsThe results revealed a negative correlation between childhood trauma and stress recovery, prominently observed in instances of emotional neglect and abuse. Individuals with heightened childhood trauma exhibited protracted stress recovery following acute stress exposure.ConclusionChildhood traumatic experiences were associated with the recovery from acute stress, as indicated by heart rate indices. These findings contribute to the foundational framework for psychological interventions tailored to individuals with a history of childhood trauma

AN ALTERNATIVE APPROACH TO INSTITUTIONAL ANALYSIS IN STRATEGIC ENVIRONMENTAL ASSESSMENT IN CHINA

This paper advocates a modification of the impact-based approach to strategic environmental assessment (SEA) which seems unable to address institutional weaknesses in most conventional SEA cases in China. It identifies a possible alternative approach, i.e. an impact-centred SEA with institutional components, and presents an analytical framework for institutional analysis, including a four-phase methodology to address and improve institutional weaknesses. Subsequently, the analytical framework is applied to an SEA pilot for a provincial transport plan in China. The case study demonstrates (1) that the proposed approach is adequate even in relatively fixed SEA processes; and (2) that the components and the logical relationships among factors elaborated on in the analytical framework are reasonable. In addition, the components of the framework that need to be improved and the perspectives for future application are discussed.Strategic environmental assessment, institutional analysis, provincial transport plan, environmental management, Hubei, China

Bridging childhood to adulthood: the impact of early life stress on acute stress responses

Background Childhood trauma exerts enduring impacts on the physical and psychological well-being of individuals in adulthood, influencing their daily functioning. This study aims to investigate the impact of childhood trauma on stress recovery in adults, concentrating on heart rate variations during acute stress exposure.Methods A cohort of 126 participants completed the Childhood Trauma Questionnaire (CTQ) and underwent the Trier Social Stress Test (TSST) to elicit acute stress, with continuous heart rate (HR) monitoring for stress recovery assessment.Results The results revealed a negative correlation between childhood trauma and stress recovery, prominently observed in instances of emotional neglect and abuse. Individuals with heightened childhood trauma exhibited protracted stress recovery following acute stress exposure.Conclusion Childhood traumatic experiences were associated with the recovery from acute stress, as indicated by heart rate indices. These findings contribute to the foundational framework for psychological interventions tailored to individuals with a history of childhood trauma

Objective Metrics for Assessing Visual Complexity of Vehicle Dashboards: A Machine-Learning Based Study

Dashboard is a central component of an in-vehicle information system (IVIS), and plays a crucial role in providing drivers with key information related but not limited to driving. With the expansion of the IVIS features, modern dashboards additionally integrate various new elements, which often leads to an increase in their visual complexity. Since high visual complexity of the dashboards threatens driving safety and performance, it is essential for researchers and designers to understand what objective features of the dashboards are related to their perceived visual complexity (PVC) so as to establish more cognitively efficient dashboards. In the present study, we refined the objective metrics of assessing visual complexity proposed in previous research and added two new dimensions, colors and animation, to better characterize recent development in the dashboard displays. We then utilized the indicators in the metrics to predict the dashboard PVC. Machine learning was innovatively applied, and the models were found to have stable performance. The study contributes reliable metrics and novel methodology to evaluate the visual complexity of the dashboards for the reference of future studies.</p

Iterative Correction Scheme Based on Discrete Cosine Transform and L1 Regularization for Fluorescence Molecular Tomography With Background Fluorescence

Goal: High-intensity background fluorescence is generally encountered in fluorescence molecular tomography (FMT), because of the accumulation of fluorescent probes in nontarget tissues or the existence of autofluorescence in biological tissues. The reconstruction results are affected or even distorted by the background fluorescence, especially when the distribution of fluorescent targets is relatively sparse. The purpose of this paper is to reduce the negative effect of background fluorescence on FMT reconstruction. Methods: After each iteration of the Tikhonov regularization algorithm, 3-D discrete cosine transform is adopted to filter the intermediate results. And then, a sparsity constraint step based on L1 regularization is applied to restrain the energy of the objective function. Results: Phantom experiments with different fluorescence intensities of homogeneous and heterogeneous background are carried out to validate the performance of the proposed scheme. The results show that the reconstruction quality can be improved with the proposed iterative correction scheme. Conclusion and Significance: The influence of background fluorescence in FMT can be reduced effectively because of the filtering of the intermediate results, the detail preservation, and noise suppression of L1 regularization

Spectral selective fluorescence molecular imaging with volume holographic imaging system

A compact volume holographic imaging (VHI) method that can detect fluorescence objects located in diffusive medium in spectral selective imaging manner is presented. The enlargement of lateral field of view of the VHI system is realized by using broadband illumination and demagnification optics. Each target spectrum of fluorescence emitting from a diffusive medium is probed by tuning the inclination angle of the transmission volume holographic grating (VHG). With the use of the single transmission VHG, fluorescence images with different spectrum are obtained sequentially and precise three-dimensional (3D) information of deep fluorescent objects located in a diffusive medium can be reconstructed from these images. The results of phantom experiments demonstrate that two fluorescent objects with a sub-millimeter distance can be resolved by spectral selective imaging

A Hybrid Method for Provincial Scale Energy-related Carbon Emission Allocation in China

Achievement of carbon emission reduction targets proposed by national governments relies on provincial/state allocations. In this study, a hybrid method for provincial energy-related carbon emissions allocation in China was developed to provide a good balance between production- and consumption-based approaches. In this method, provincial energy-related carbon emissions are decomposed into direct emissions of local activities other than thermal power generation and indirect emissions as a result of electricity consumption. Based on the carbon reduction efficiency principle, the responsibility for embodied emissions of provincial product transactions is assigned entirely to the production area. The responsibility for carbon generation during the production of thermal power is borne by the electricity consumption area, which ensures that different regions with resource endowments have rational development space. Empirical studies were conducted to examine the hybrid method and three indices, per capita GDP, resource endowment index and the proportion of energy-intensive industries, were screened to preliminarily interpret the differences among China’s regional carbon emissions. Uncertainty analysis and a discussion of this method are also provided herein