Hydrogen induced fracture characteristics of single crystal nickel-based superalloys

A stereoscopic method for use with x ray energy dispersive spectroscopy of rough surfaces was adapted and applied to the fracture surfaces single crystals of PWA 1480E to permit rapid orientation determinations of small cleavage planes. The method uses a mathematical treatment of stereo pair photomicrographs to measure the angle between the electron beam and the surface normal. One reference crystal orientation corresponding to the electron beam direction (crystal growth direction) is required to perform this trace analysis. The microstructure of PWA 1480E was characterized before fracture analysis was performed. The fracture behavior of single crystals of the PWA 1480E nickel-based superalloy was studied. The hydrogen-induced fracture behavior of single crystals of the PWA 1480E nickel-based superalloy was also studied. In order to understand the temperature dependence of hydrogen-induced embrittlement, notched single crystals with three different crystal growth orientations near zone axes (100), (110), and (111) were tensile tested at 871 C (1600 F) in both helium and hydrogen atmospheres at 34 MPa. Results and conclusions are given

Kondo and charge fluctuation resistivity due to Anderson impurities in graphene

Motivated by experiments on ion irradiated graphene, we compute the resistivity of graphene with dilute impurities. In the local moment regime we employ the perturbation theory up to third order in the exchange coupling to determine the behavior at high temperatures within the Kondo model. Resistivity due to charge fluctuations is obtained within the mean field approach on the Anderson impurity model. Due to the linear spectrum of the graphene the Kondo behavior is shown to depend on the gate voltage applied. The location of the impurity on the graphene sheet is an important variable determining its effect on the Kondo scale and resistivity. Our results show that for chemical potential nearby the node the charge fluctuations is responsible for the observed temperature dependence of resistivity while away from the node the spin fluctuations take over. Quantitative agreement with experimental data is achieved if the energy of the impurity level varies linearly with the chemical potential.Comment: 17 pages, 15 figures, published versio

Segue: Overviewing Evolution Patterns of Egocentric Networks by Interactive Construction of Spatial Layouts

Getting the overall picture of how a large number of ego-networks evolve is a common yet challenging task. Existing techniques often require analysts to inspect the evolution patterns of ego-networks one after another. In this study, we explore an approach that allows analysts to interactively create spatial layouts in which each dot is a dynamic ego-network. These spatial layouts provide overviews of the evolution patterns of ego-networks, thereby revealing different global patterns such as trends, clusters and outliers in evolution patterns. To let analysts interactively construct interpretable spatial layouts, we propose a data transformation pipeline, with which analysts can adjust the spatial layouts and convert dynamic egonetworks into event sequences to aid interpretations of the spatial positions. Based on this transformation pipeline, we developed Segue, a visual analysis system that supports thorough exploration of the evolution patterns of ego-networks. Through two usage scenarios, we demonstrate how analysts can gain insights into the overall evolution patterns of a large collection of ego-networks by interactively creating different spatial layouts.Comment: Published at IEEE Conference on Visual Analytics Science and Technology (IEEE VAST 2018

Mapping maritime power and control: a study of the late eighteenth century Qisheng yanhai tu (a coastal map of the seven provinces)

This article surveys a Chinese coastal map (haitu), similar to the sea charts used in the west. The map was produced in the late eighteenth century under the official supervision of the Qing court. Titled Qisheng yanhai tu (A coastal map of the seven provinces), this was one of very few maps made before the First Opium War that charted the contours of coastal regions and the immediate sea space under the control of the Qing Empire. It is also notable for the detailed paratextual information printed on the map touching upon various issues, such as the importance of coastal defense, the significance of the Bohai Sea, the dividing logic between inner and outer sea spaces, as well as the topographies of strategic islands off the China coast. In line with cartographic depictions, these paratextual materials indicate the way that the Manchu Empire conceptualized the maritime frontier in a deliberate and preventive manner. Through careful analysis of this coastal map, we can reexamine the overriding, conventional conception of the Qing Empire as strictly a land-based, continental power that cared little about the ocean before the arrival of western gunboats in the mid-nineteenth centur

Hero or Villain? The evolving legacy of Shi Lang in China and Taiwan

For over two centuries, some of China’s most prominent officials, literary figures, and intellectuals have paid special attention to the legacy of Shi Lang. Compared to many other historical figures, in East Asia’s cross-strait tensions and geopolitics, Shi Lang remains essential to our understanding of this region’s troubled past and the murky outlook for its future. Although the image of Shi Lang continues to mean different things to different people, to some degree, his significance to one particular community is also communicated to other communities. As a result, by analysing most of the previous appraisals and examinations of Shi Lang, we can see the historical narratives of this man as being continually under construction in a shifting and mutually reinforcing process. This paper aims to examine the ways in which the legacy of Shi Lang has percolated throughout Chinese history, since the Qing Dynasty, and also how it continues to function in the present day. It is fascinating to not only delineate how the story of Shi Lang has evolved as a legacy, but also to explore the rich variety of ways in which an individual or a community has adapted the narratives that makes up the story of Shi Lang to suit the demands of different historical settings and perspectives

A port city in Northeast China: Dengzhou in the Long eighteenth century

AbstractIf we were asked to recall a coastal city of early modern China, most of us would choose Shanghai, Canton, Xiamen, or Macau. These port cities became famous for facilitating trans-regional sea trade that linked the Qing Empire to the rest of the world. Attentive observers know that all of these cities are located on the Southeast China coast, by which we mean the coastal areas south of Shanghai. Taking Shanghai as the dividing line between the northeastern and southeastern coastlines, the port cities of the south are far more likely to be familiar to us than are those of the north. I consider this phenomenon (i.e. the focus on the coast of early modern China) to be a “Southeast China centrism.” And although we might all concede that some southeastern seaports were vital to transoceanic interactions, it is shortsighted to ignore the northern port cities and the role they played in connecting China with the maritime world. In this article I investigate the importance of Northeast China's port cities by focusing particular attention on the less familiar coastal seaport of Dengzhou. By detailing and examining the political and economic importance of this port city in the early modern period, I will show that Qing China's northeastern coast was no less important than the southeast. Even if China's northern port cities might not have been as economically vibrant as those in the south, we should not overlook their functions and histories. Indeed, they also attained unique patterns of political and economic development throughout the long eighteenth century.</jats:p

Consuming China in early modern England and beyond: a survey and reexamination

If we traveled back in time to the first half of the eighteenth century, we might notice that the cargo aboard an East Indiaman was rather diversified. But of these different products from different countries, a sizable number of them were manufactured in and originated from China. Why was China, alone among many other countries, able to secure its place as a world factory at the time? In this paper, I will suggest that we could not possibly understand how tea and porcelain became synonyms for China without tracing their histories back to the early modern world. We would not be able to deepen our understanding of Anglo-Chinese relations without taking into consideration the flow and circulations of goods between the two powers. My purpose here, therefore, is to outline these very connections throughout the early modern era, roughly from the late seventeenth century to the mid-nineteenth century, based on the fascinating studies conducted by pioneering historians in the field over the past few decades. If we follow the life histories of some of the Chinese commodities, can we determine the ways in which those imported items interacted with the European market in general and the British in particular? Other than treating these commodities as marketable goods, are there any other intellectual perspectives available to help us better comprehend their associations with the early modern world

Qing China and its offshore islands in the long eighteenth century

A significant paradigm shift in the examination of China's engagement with the maritime world has taken place over the past decade. The conventional image of the Qing dynasty in the long eighteenth century as being merely land-orientated has now become obsolete. Historians are no longer satisfied with this stereotype and have put aside the conception that the Qing only realized the importance of strategic marine governance after the First Opium War. In view of this historiographical turn, I seek to deepen our understanding of the Great Qing in relation to the sea. By focusing on a series of sea charts, alongside some relevant palace papers, from the eighteenth and early nineteenth centuries, I will argue that the Qing's process of locating and charting those offshore islands was an essential, indicative, and demonstrative step for the central authority to project its imperial power onto the waters off the coast of China long before the arrival of Western gunboats in the age of global rivalry

Floating-disk parylene microvalve for self-regulating biomedical flow controls

A novel self-regulating parylene micro valve is presented in this paper with potential applications for biomedical flow controls. Featuring a free-floating bendable valve disk and two-level valve seat, this surface-micromachined polymeric valve accomplishes miniature pressure/flow rate regulation in a band-pass profile stand-alone without the need of power sources or active actuation. Experimental data of underwater testing results have successfully demonstrated that the microfabricated in-channel valve can regulate water flow at 0-80 mmHg and 0-10 µL/min pressure/flow rate level, which is perfectly suitable for biomedical and lab-on-a-chip applications. For example, such biocompatible microvalve can be incorporated in ocular implants for control of eye fluid drainage to fulfill intraocular pressure (IOP) regulation in glaucoma patients