scholarly journals The ultra-violet spectrum of magnesium hydride.—II. The many-lined γ-system

During the course of investigation of the bands at λλ 5622, 5211 and 4845, emitted by the magnesium arc in hydrogen at low pressures, Prof. A. Fowler observed that they were always accompanied by a further band at λ 2430 and by series of double lines in the region λ 2940 to λ 3100. These features of this spectrum seemed to merit further study in view of the important part played by the spectra of other molecules with 13 electrons (CN, BO, BeF, CO + , N 2 + ) in the classification of molecular energy levels. Further, MgH is one of the interesting series of hydrides (BeH, MgH, CaH, ZnH, CdH, HgH) which show a pair of excited P states, with doublet separation increasing with molecular weight, closely resembling the lowest 2 P state of the preceding monovalent atoms (Li, Na, K, Cu, Ag, Au). An account of an analysis of the band at λ 2430 was given in a previous paper; the present paper deals with the series of double lines. For convenience the system in the visible region is referred to as the α-system, the one represented by the band at λ 2430 as the β-system, and that about to be described as the γ-system.

The system of bands in the visible region of the emission spectrum of magnesium hydride is now well known. The bands with heads at λλ 5622, 5211, 4845 were first measured by Prof. A. Fowler, who arranged many of the strongest lines in empirical series for identification with absorption lines in the spectra of sun-spots. Later, Heurlinger rearranged these series in the now familiar form of P, Q and R branches, and considered them, with the OH group, as typical of doublet systems in his classification of the fine structure of bands. More recently, W. W. Watson and P. Rudnick have remeasured these bands, using the second order of a 21-foot concave grating, and have carried out a further investigation of the fine structure in the light of the present theory of band spectra. Their detection of an isotope effect of the right order of magnitude, considered with the general structure of the system, and the experimental work on the production of the spectrum, seems conclusive in assigning these bands to the diatomic molecule MgH. The ultra-violet spectrum of magnesium hydride is not so well known. The band at λ 2430 and the series of double lines in the region λ 2940 to λ 3100, which were recorded by Prof. Fowler in 1909 as accompanying the group of bands in the visible region, appear to have undergone no further investigation. In view of the important part played by hydride band spectra in the correlation of molecular and atomic electronic energy levels, it was thought that a study of these features might prove of interest in yielding further information on the energy states of the MgH molecule. The present paper deals with observations on the band at λ 2430; details of an investigation of the other features of the ultra-violet spectrum will be given in a later communication.


1888 ◽  
Vol 43 (258-265) ◽  
pp. 347-348

In a former communication the authors described simultaneously with Dr. Huggins the strongest portion of the spectrum of water, subsequently they described a second less strong but more refrangible section of the same spectrum. M. Deslandres has noticed a third still more refrangible section. The authors now find that the spectrum extends, with diminishing intensity, into the visible region on the one hand, and far into the ultra-violet on the other.


In a previous paper published in these 'Proceedings' a report was given of some measurements on the energy losses suffered by electrons in nitrogen at pressures sufficiently low to ensure that practically only single collisions would take place. Electrons of homogeneous speed drawn from a hot cathode were fired through the gas and the velocity distribution in the emergent beam subsequently analysed by a combination of one longitudinal and one transversal electric field, the latter of a kind which would give refocussing of a slightly divergent incident beam at the entrance slit of the electron detector. The two most prominent characteristic energy losses observed in nitrogen were shown to be associated with energy levels known form the absorption spectrum of the nitrogen molecule in the far ultra-violet. The present investigation is an extension of this work to the two gases carbon monoxide and carbon dioxide. The former of these two was chosen as a typical diatomic gas, the energy levels of which are now fairly well known through the work of several investigators in recent years. Carbon dioxide was studied in addition to this, in view of the possibility that traces of this gas could have been formed from the carbon monoxide in contact with the hot cathode in the experiments with the latter gas. The experimental arrangements remained essentially the same as in the case of nitrogen. The tube was the one described in the previous paper referred to. The primary slit S 1 of sheet copper, which had been contaminated by mercury in the meantime when the tube was left standing without cooling the traps, was now replaced by a similar slit made of sheet silver. The cathode was coated with a mixture of barium and strontium oxides. As in the case of nitrogen all measurements were made with the gas continuously flowing through the apparatus, the pressure readings referring to the conditions in the tube through which the gas was admitted to the collision space.


2019 ◽  
Vol 37 (1) ◽  
pp. 89-110
Author(s):  
Rachel Fensham

The Viennese modern choreographer Gertrud Bodenwieser's black coat leads to an analysis of her choreography in four main phases – the early European career; the rise of Nazism; war's brutality; and postwar attempts at reconciliation. Utilising archival and embodied research, the article focuses on a selection of Bodenwieser costumes that survived her journey from Vienna, or were remade in Australia, and their role in the dramaturgy of works such as Swinging Bells (1926), The Masks of Lucifer (1936, 1944), Cain and Abel (1940) and The One and the Many (1946). In addition to dance history, costume studies provides a distinctive way to engage with the question of what remains of performance, and what survives of the historical conditions and experience of modern dance-drama. Throughout, Hannah Arendt's book The Human Condition (1958) provides a critical guide to the acts of reconstruction undertaken by Bodenwieser as an émigré choreographer in the practice of her craft, and its ‘materializing reification’ of creative thought. As a study in affective memory, information regarding Bodenwieser's personal life becomes interwoven with the author's response to the material evidence of costumes, oral histories and documents located in various Australian archives. By resurrecting the ‘dead letters’ of this choreography, the article therefore considers how dance costumes offer the trace of an artistic resistance to totalitarianism.


Imbizo ◽  
2017 ◽  
Vol 7 (1) ◽  
pp. 40-54
Author(s):  
Oyeh O. Otu

This article examines how female conditioning and sexual repression affect the woman’s sense of self, womanhood, identity and her place in society. It argues that the woman’s body is at the core of the many sites of gender struggles/ politics. Accordingly, the woman’s body must be decolonised for her to attain true emancipation. On the one hand, this study identifies the grave consequences of sexual repression, how it robs women of their freedom to choose whom to love or marry, the freedom to seek legal redress against sexual abuse and terror, and how it hinders their quest for self-determination. On the other hand, it underscores the need to give women sexual freedom that must be respected and enforced by law for the overall good of society.


Author(s):  
I. Kukhtevich

Functional autonomic disorders occupy a significant part in the practice of neurologists and professionals of other specialties as well. However, there is no generally accepted classification of such disorders. In this paper the authors tried to show that functional autonomic pathology corresponds to the concept of somatoform disorders combining syndromes manifested by visceral, borderline psychopathological, neurological symptoms that do not have an organic basis. The relevance of the problem of somatoform disorders is that on the one hand many health professionals are not familiar enough with manifestations of borderline neuropsychiatric disorders, often forming functional autonomic disorders, and on the other hand they overestimate somatoform symptoms that are similar to somatic diseases.


2020 ◽  
Author(s):  
Kunal Srivastava ◽  
Ryan Tabrizi ◽  
Ayaan Rahim ◽  
Lauryn Nakamitsu

<div> <div> <div> <p>Abstract </p> <p>The ceaseless connectivity imposed by the internet has made many vulnerable to offensive comments, be it their physical appearance, political beliefs, or religion. Some define hate speech as any kind of personal attack on one’s identity or beliefs. Of the many sites that grant the ability to spread such offensive speech, Twitter has arguably become the primary medium for individuals and groups to spread these hurtful comments. Such comments typically fail to be detected by Twitter’s anti-hate system and can linger online for hours before finally being taken down. Through sentiment analysis, this algorithm is able to distinguish hate speech effectively through the classification of sentiment. </p> </div> </div> </div>


Author(s):  
Christopher Hanlon

Emerson’s Memory Loss is about an archive of texts documenting Emerson’s intellectual state during the final phase of his life, as he underwent dementia. It is also about the way these texts provoke a rereading of the more familiar canon of Emerson’s thinking. Emerson’s memory loss, Hanlon argues, contributed to the shaping of a line of thought in America that emphasizes the social over the solipsistic, the affective over the distant, the many over the one. Emerson regarded his output during the time when his patterns of cognition transformed profoundly as a regathering of focus on the nature of memory and of thinking itself. His late texts theorize Emerson’s experience of senescence even as they disrupt his prior valorizations of the independent mind teeming with self-sufficient conviction. But still, these late writings have succumbed to a process of critical forgetting—either ignored by scholars or denied inclusion in Emerson’s oeuvre. Attending to a manuscript archive that reveals the extent to which Emerson collaborated with others—especially his daughter, Ellen Tucker Emerson—to articulate what he considered his most important work even as his ability to do so independently waned, Hanlon measures the resonance of these late texts across the stretch of Emerson’s thinking, including his writing about Margaret Fuller and his meditations on streams of thought that verge unto those of his godson, William James. Such ventures bring us toward a self defined less by its anxiety of overinfluence than by its communality, its very connectedness with myriad others.


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