Novel Development of Super-Resolution Force Spectroscopy and Applications in Biological Systems

This dissertation focuses on applications of new techniques that are used to investigate interactions in biological systems. Atomic magnetometry and ultrasound have been extensively used as individual techniques in various physical and engineering fields. Their combination, however, has been rare. Super-resolution force spectroscopy (SURFS) was developed based on the integration of these two techniques, and it has unique biophysical applications in studying drug-DNA interactions and ribosomal translocations. I demonstrate that SURFS has a high force resolution of 0.5 pN by resolving the dissociation forces of 12 base pairs of DNA duplex and 11 base pairs of DNA duplex with the drug daunomycin. The SURFS technique was used to determine the positions of the ribosome on the mRNA at two distinct states. I found that from the post-translocation state (Post) to the subsequent pre-translocation state (Pre), the ribosome moves spontaneously by nearly half a nucleotide. The application of SURFS was expanded in biophysics. I was able to precisely resolve three small molecules binding with two DNA sequences, which were difficult to distinguish by using previous force spectroscopic techniques. The results indicate that the differential binding forces caused by drug binding correlate with enthalpy instead of free energy, thus providing an alternative physical parameter for optimizing chemotherapeutic drugs. Force-induced visualization (FIV) can determine the functional position of nucleic acids with single-nucleotide resolution by visually distinguishable states. The use of an adjustable mechanical force overcomes the variations of buffer conditions and analyte concentrations. Probing the mRNA movement during ribosomal translocation, and revealing the interacting sites and strengths of DNA-binding drugs were investigated. The experimental setup used to record and quantify data was achieved with an affordable and portable device coupled with a smart phone. Massive detections were achieved by simultaneously using acoustic radiation force. The simplicity of the method, low cost of the device, and high efficiency of the measurements have broad applications for FIV in biomolecular research.Chemistry, Department o

Wind Environment Simulation and Optimisation Strategies for Block Spatial Forms in Cold Low Mountainous Areas—A Case Study of Changchun, China

Low mountainous areas provide high-quality ecological environments, offering a high urban development value globally. However, cold low mountainous areas are greatly affected by wind environments. Therefore, this study investigates a simulated block wind environment in a typical city in a cold low mountainous area. As opposed to previous work, we put forward the block spatial modes quantitatively for cold low mountainous areas. Computational fluid dynamics (CFD) technology is used to simulate the wind environment of building blocks, including point-type high-rise buildings and row-type multi-story buildings. We propose a new targeted wind environment measurement system developed using PHOENICS 2018 and a spatial combination model using urban information sensing for sustainable development. By comparing the average wind speed (WAS) and calm wind area ratio (SCA) under different simulation conditions, we were able find that when the building form, slope direction, and slope were constant, WAS was inversely proportional to SCA, following the order of south slope > west slope > southwest slope > southeast slope. Second, proper selection of 1:2 and 1:3 ratios for point-type high-rise buildings (HPT) can provide good ventilation for cold low mountainous areas. In addition, continuous high-rise buildings should be avoided. These strategies have been applied in practice in the spatial design of the Lianhuashan tourist resort in Changchun. Possible optimization strategies for planners and governments could include promoting pedestrian spatial environments in these special areas. Moreover, this research is significant for the collection and mining of data-based wind information in cold low mountainous areas, thereby providing scientific quantitative evaluation methods and spatial organisation optimisation guidelines

Research on Performance Improvement of Photovoltaic Cells and Modules Based on Black Silicon

This paper mainly studied the electrical performance improvement of black silicon photovoltaic (PV) cells and modules. The electrical performance of the cells and modules matched with black silicon was optimized through three different experiments. Firstly, in the pre-cleaning step, the effect of lotion selection on the cell performance was studied. Compared with alkaline lotion, using acidic lotion on black silicon wafer can achieve an efficiency improvement of the black silicon cell by nearly 0.154%. Secondly, the influence of oxygen flux control of the thermal oxidation step on the improvement of cell efficiency was studied. The addition of the thermal oxidation step and its oxygen flux control resulted in an efficiency increase of the black silicon cell of nearly 0.11%. The most optimized volume control of the oxygen flux is at 2200 standard cubic centimeter per minute (SCCM). Finally, in the module packaging process, the selection of components will also greatly affect the performance of the black silicon PV module. The most reasonable selection of components can increase the output power of the black silicon PV module by 6.13 W. In a word, the technical indication of the electrical performance improvement suggested in this study plays an important guiding role in the actual production process