Nonresonant Multiphoton Ionization of Alkaline Earth Atoms in Intense Laser Fields.

When an atomic beam interacts with a high intensity laser beam, ionization occurs even if the photon energy is less than the threshold level for ionization of the atom. In this thesis, nonresonant multiphoton ionization of alkaline-earth atoms is examined experimentally. Since alkaline-earth atoms have doubly excited states just above and sometimes below the first ionization threshold level and are easily ionized with relatively low intensity, they are ideally suited for studying the role of electron correlations in multiphoton ionization. This motivated a careful and detailed investigation of the correlation of electrons and the multiphoton ionization mechanism. A spectroscopic study on photoelectrons arising from nonresonant multiphoton ionization of calcium and magnesium atoms up to 10\sp{13}W/cm\sp2 is described. The emphasis is placed on photoelectron spectra, and their variations with laser wavelength, intensity, and polarization. Also, the ionization process of doubly charged ions which can be produced either by a stepwise process or by the simultaneous removal of two electrons is discussed

The role of the government in promoting industrialization and human capital accumulation in Korea

노트 : - This PDF is a selection from an out-of-print volume from the National Bureau of Economic Research - Volume Title: Growth theories in light of the East Asian experienc

A Comparison of the Query Execution Algorithms in Secure Database System

In accordance with the database management, DAS(Database as Service) model is one solution for outsourcing. However, we need some data protection mechanisms in order to maintain the database security The most effective algorithm to secure databases from the security threat of third party attackers is to encrypt the sensitive data within the database. However, once we encrypt the sensitive data, we have difficulties in queries execution on the encrypted database. In this paper, we focus on the search process on the encrypted database. We proposed the selective tuple encryption method using Bloom Filter which could tell us the existence of the data. Finally, we compare the search performance between the proposed method and the other encryption methods we know

Cost-Effective, Time-Efficient Passenger Rail System for the Eastern United States

A program was developed using a genetic algorithm and automated lookup features to design an efficient passenger rail system for the eastern-half of the United States connecting large cities, metropolitan populations greater than two million, with overnight rail service. The results of the program predicted a passenger starting at the farthest point of the system boards the train at 16:02 on average and arrives at a different point of the system at 07:57 on average the following day, assuming the train travels an average speed of 70 mph. The design used actual distances by train track where possible. The system was modeled with six trains that meet at a hub and exchange passengers and continue on to their destination.The optimal solution had a total one-way minimum distance of 4334 km (2693 miles). Assuming the same ridership that currently exists on a popular train route, ticket prices would average $62 (USD) for a one-way ticket. For this system to be feasible, the government would need to own or lease one set of tracks for all the routes determined, build a hub for passengers to transfer trains near Charleston,WV, and ensure the trains are unimpeded by other trains. Installing tracks that go around cities that the trains do not stop at would be a great benefit also. With advances in communication, GPS, and train control technology, this article points out the benefits of publically available tracks to form a transportation network similar to that found in road, air, and water traffic

Synthesis and Properties of Fluorinated Polyimides from Rigid and Twisted Bis(Trifluoromethyl)Benzidine for Flexible Electronics

Fluorinated polyimides were prepared from the twisted benzidine monomer containing two trifluoromethyl (CF3) groups on one aromatic ring. The diamine monomer having a rigid and nonplanar structure was polymerized with typical dianhydride monomers including BPDA, BTDA, ODPA, 6-FDA, and PMDA, to obtain the corresponding polyimides. Most polyimides are soluble in organic solvents due to their twisted chain structure and can be solution cast into flexible and tough films. These films have a UV-vis absorption cut-off wavelength at 354–398 nm and a light transparency of 34–90% at a wavelength of 550 nm. They also have tensile strengths of 92–145 MPa and coefficients of thermal expansion (CTE) of 6.8–63.1 ppm/°C. The polymers exhibited high thermal stability with 5% weight loss at temperatures ranging from 535 to 605°C in nitrogen and from 523 to 594°C in air, and high glass temperature (Tg) values in the range of 345–366°C. Interestingly, some of the soluble polyimides showed thermo-responsive behaviors in organic solvents presumably due to the multiple hydrogen bondings with unsymmetrically positioned two CF3 groups along the polymer chains

Estimating animal pose using deep learning a trained deep learning model outperforms morphological analysis

INTRODUCTION: Analyzing animal behavior helps researchers understand their decision-making process and helper tools are rapidly becoming an indispensable part of many interdisciplinary studies. However, researchers are often challenged to estimate animal pose because of the limitation of the tools and its vulnerability to a specific environment. Over the years, deep learning has been introduced as an alternative solution to overcome these challenges. OBJECTIVES: This study investigates how deep learning models can be applied for the accurate prediction of animal behavior, comparing with traditional morphological analysis based on image pixels. METHODS: Transparent Omnidirectional Locomotion Compensator (TOLC), a tracking device, is used to record videos with a wide range of animal behavior. Recorded videos contain two insects: a walking red imported fire ant (Solenopsis invicta) and a walking fruit fly (Drosophila melanogaster). Body parts such as the head, legs, and thorax, are estimated by using an open-source deep-learning toolbox. A deep learning model, ResNet-50, is trained to predict the body parts of the fire ant and the fruit fly respectively. 500 image frames for each insect were annotated by humans and then compared with the predictions of the deep learning model as well as the points generated from the morphological analysis. RESULTS: The experimental results show that the average distance between the deep learning-predicted centroids and the human-annotated centroids is 2.54, while the average distance between the morphological analysis-generated centroids and the human-annotated centroids is 6.41 over the 500 frames of the fire ant. For the fruit fly, the average distance of the centroids between the deep learning- predicted and the human-annotated is 2.43, while the average distance of the centroids between the morphological analysis-generated and the human-annotated is 5.06 over the 477 image frames. CONCLUSION: In this paper, we demonstrate that the deep learning model outperforms traditional morphological analysis in terms of estimating animal pose in a series of video frames