The Gamma-Ray Imaging Spectrometer (GRIS): A new balloon-borne experiment for gamma-ray line astronomy

High resolution gamma-ray spectroscopy is a relatively new field that holds great promise for further understanding of high energy astrophysical processes. When the high resolution gamma-ray spectrometer (GRSE) was removed from the GRO payload, a balloon program was initiated to permit continued development and improvement of instrumentation in this field, as well as continued scientific observations. The Gamma-Ray Imaging Spectrometer (GRIS) is one of the experiments selected as part of this program. The instrument contains a number of new and innovative features that are expected to produce a significant improvement in source location accuracy and sensitivity over previous balloon and satellite experiments

A coded aperture imaging system optimized for hard X-ray and gamma ray astronomy

A coded aperture imaging system was designed for the Gamma-Ray imaging spectrometer (GRIS). The system is optimized for imaging 511 keV positron-annihilation photons. For a galactic center 511-keV source strength of 0.001 sq/s, the source location accuracy is expected to be + or - 0.2 deg

Bringing the World Home

Bringing the World Home sheds new light on China’s vibrant cultural life between 1895 and 1919—a crucial period that marks a watershed between the conservative old regime and the ostensibly iconoclastic New Culture of the 1920s. Although generally overlooked in the effort to understand modern Chinese history, the era has much to teach us about cultural accommodation and is characterized by its own unique intellectual life. This original and probing work traces the most significant strands of the new post-1895 discourse, concentrating on the anxieties inherent in a complicated process of cultural transformation. It focuses principally on how the need to accommodate the West was reflected in such landmark novels of the period as Wu Jianren’s "Strange Events Eyewitnessed in the Past Twenty Years" and Zhu Shouju’s "Tides of the Huangpu", which began serial publication in Shanghai in 1916

Bringing the World Home: Appropriating the West in Late Qing and Early Republican China

Bringing the World Home sheds new light on China’s vibrant cultural life between 1895 and 1919—a crucial period that marks a watershed between the conservative old regime and the ostensibly iconoclastic New Culture of the 1920s. Although generally overlooked in the effort to understand modern Chinese history, the era has much to teach us about cultural accommodation and is characterized by its own unique intellectual life. This original and probing work traces the most significant strands of the new post-1895 discourse, concentrating on the anxieties inherent in a complicated process of cultural transformation. It focuses principally on how the need to accommodate the West was reflected in such landmark novels of the period as Wu Jianren’s Strange Events Eyewitnessed in the Past Twenty Years and Zhu Shouju’s Tides of the Huangpu, which began serial publication in Shanghai in 1916. The negative tone of these narratives contrasts sharply with the facile optimism that characterizes the many essays on the "New Novel" appearing in the popular press of the time. Neither iconoclasm nor the wholesale embrace of the new could square the contradicting intellectual demands imposed by the momentous alternatives presenting themselves. An electronic version of this book is freely available thanks to the support of libraries working with Knowledge Unlatched, a collaborative initiative designed to make high-quality books open access for the public good. The open-access version of this book is licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), which means that the work may be freely downloaded and shared for non-commercial purposes, provided credit is given to the author. Derivative works and commercial uses require permission from the publisher.Knowledge Unlatche

Total Synthesis of Welwitindolinone Natural Products

Chapter one provides a summary of efforts towards the syntheses of the welwitindolinones with bicyclo[4.3.1]decane cores. Emphasis is given to more recent approaches that have successfully assembled the bicyclic core of the natural products. Chapters two and three are a discussion of our studies relating to a model system of the welwitindolinone natural products. Chapter two focuses on the use of an aryne cyclization to assemble the bicyclo[4.3.1]decane framework of the welwitindolinones. Chapter three covers initial attempts to install the bridgehead nitrogen substituent present in the natural products in addition to the synthesis of a functionalized aryne cyclization substrate. Chapters four and five present our total syntheses of the welwitindolinone natural products. The enantiospecific total syntheses of N-methylwelwitindolinone C isothiocyanate, N-methylwelwitindolinone C isonitrile, 3-hydroxy-N-methylwelwitindolinone C isothiocyanate and 3-hydroxy-N-methylwelwitindolinone C isonitrile are detailed. The approach to these natural products features an aryne cyclization to construct the bicyclo[4.3.1]decane core of the molecules as well as a late-stage nitrene insertion reaction to install the bridgehead nitrogen substituent. The use of a deuterium kinetic isotope effect to improve the yield of the nitrene insertion is also presented. In addition, a computational method to predict the stereochemistry of a previously unconfirmed stereocenter in the hydroxylated natural products as well as experimental validation of the computational findings is discussed