Evidence of a solvent-mediated barrier to radiationless decay in the state of thiophosgene in solution

1995 ◽  
Vol 73 (1) ◽  
pp. 131-138 ◽  
Author(s):  
Jieming Li ◽  
Ronald P. Steer

Thiophosgene, Cl2CS, has been excited in the near-uv and the resulting quantum yields of [Formula: see text] fluorescence and of Cl2CS consumption have been measured as a function of solvent composition (perfluoro-n-hexane, n-hexane, CCl4), temperature, and excitation wavelength. In agreement with previous work it is shown that (i) nonradiative processes dominate the decay of the [Formula: see text] state in solution, and (ii) perfluoroalkane solvents act as inert "heat baths". The process by which the [Formula: see text] state is apparently "quenched" by CCl4 and n-hexane has been discovered. The nonradiative process leading to [Formula: see text] decay involves activation and crossing a barrier, the height of which is a function of the nature and composition of the solvent. CCl4 and n-hexane do not quench the excited state, but instead accelerate its rate of relaxation by lowering the barrier between the bound, radiative portion of the surface and a dark, unbound region. There is evidence that CCl4 or n-hexane form clusters around a Cl2CS solute molecule in mixed perfluoroalkane–CCl4 or n-hexane solutions. Barrier crossing leads to photodecomposition via at least two parallel paths, one free radical (Cl + ClCS) and the other likely molecular (Cl2 + CS), the relative contributions of which are a function of excitation wavelength. Keywords: thiophosgene, photochemistry, solvent-mediated barrier crossing.

1970 ◽  
Vol 48 (1) ◽  
pp. 25-32 ◽  
Author(s):  
B. Francis ◽  
A. G. Sherwood

The mercury photosensitized decomposition of 2,5-dihydrofuran was studied in the vapor phase at 25 ± 2 °C. Major products are carbon monoxide, propene, and hydrogen, while biallyl, allene, methylacetylene, furan, 2,3-dihydrofuran, tetrahydrofuran, and small amounts of three unidentified products are also produced. The quantum yields of all products are decreased by increasing substrate pressure, indicating collisional deactivation of an excited state precursor which, at low pressures, decomposes according to the scheme [Formula: see text]The product P is not furan and its possible identity is discussed. The free radical component of the reaction was further studied by carrying out the reaction in the presence of nitric oxide. The results are consistent with the above processes.


2001 ◽  
Vol 667 ◽  
Author(s):  
Garry Rumbles ◽  
Don Selmarten ◽  
Randy E. Ellingson ◽  
Jeff Blackburn ◽  
Pingrong Yu ◽  
...  

ABSTRACTWe report photoluminescence, linear absorption and femto-second transient bleaching spectra for a colloidal solution of indium phosphide (InP) quantum dots at ambient temperatures. The photoluminescence quantum yield is shown to depend not only upon the size of the quantum dots, with larger dots exhibiting higher quantum yields, but also upon the excitation wavelength. At short wavelengths, photoluminescence excitation spectra deviate markedly from the absorption spectra indicating that an efficient non-radiative deactivation pathway becomes prominent at these higher photon energies. We interpret this observation in terms of an inefficient relaxation mechanism between the second excited state and the lowest energy excited state from which the emission emanates. The results are consistent with the existence of a phonon bottleneck.


2016 ◽  
Vol 6 (2) ◽  
pp. 118-135
Author(s):  
Lucia Della Torre

Not very long ago, scholars saw it fit to name a new and quite widespread phenomenon they had observed developing over the years as the “judicialization” of politics, meaning by it the expanding control of the judiciary at the expenses of the other powers of the State. Things seem yet to have begun to change, especially in Migration Law. Generally quite a marginal branch of the State's corpus iuris, this latter has already lent itself to different forms of experimentations which then, spilling over into other legislative disciplines, end up by becoming the new general rule. The new interaction between the judiciary and the executive in this specific field as it is unfolding in such countries as the UK and Switzerland may prove to be yet another example of these dynamics.


2019 ◽  
Vol 34 (2) ◽  
Author(s):  
Sipho Stephen Nkosi

The note is about the appeal lodged by the late Mrs Winnie Madikizela-Mandela to the SCA against the decision of the Eastern Cape High Court, Mthatha, dismissing her application for review in 2014. In that application, she sought to have reviewed the decision of the Minister of Land Affairs, to transfer the now extended and renovated Qunu property to Mr Mandela and to register it in his name. Because her application was out of time, she also applied for condonation of her delay in making the application. The court a quo dismissed both applications with costs, holding that there had been an undue delay on her part. Mrs Mandela then approached the Supreme Court of Appeal, for special leave to appeal the decision of the court a quo. Two questions fell for decision by the SCA: whether there was an unreasonable and undue delay on Mrs Mandela’s part in instituting review proceedings; and whether the order for costs was appropriate in the circumstances of the case. The SCA held that there was indeed an unreasonable delay (of seventeen years). Shongwe AP (with Swain, Mathopo JJA, Mokgothloa and Rodgers AJJA concurring) held that the fact that there had been an undue delay does not necessarily mean that an order for costs should, of necessity, particularly where, as in this case, the other litigant is the state. It is the writer’s view that two other ancillary points needed to be raised by counsel and pronounced on by the Court: (a) the lawfulness and regularity of the transfer of the Qunu property to Mr Mandela; and (b) Mrs Mandela’s status as a customary-law widow—in relation to Mr Mandela.


2017 ◽  
Vol 1 (1) ◽  
pp. 90
Author(s):  
Dian Septiandani ◽  
Abd. Shomad

Zakat is one of principal worship requiring every individual (<em>mukallaf</em>) with considerable property to spend some of the wealth for zakat under several conditions applied within. On the other hand, tax is an obligation assigned to taxpayers and should be deposited into the state based on policies applied, with no direct return as reward, for financing the national general expense. In their development, both zakat and tax had quite attention from Islamic economic thought. Nevertheless, we, at first, wanted to identify the principles of zakat and tax at the time of Rasulullah SAW. Therefore, this study referred to normative research. The primary data was collected through library/document research and the secondary one was collected through literature review by inventorying and collecting textbooks and other documents related to the studied issue.


Author(s):  
Anatolii Petrovich Mykolaiets

It is noted that from the standpoint of sociology, “management — a function of organized systems of various nature — (technical, biological, social), which ensures the preservation of their structure, maintaining a certain state or transfer to another state, in accordance with the objective laws of the existence of this system, which implemented by a program or deliberately set aside”. Management is carried out through the influence of one subsystem-controlling, on the other-controlled, on the processes taking place in it with the help of information signals or administrative actions. It is proved that self-government allows all members of society or a separate association to fully express their will and interests, overcome alienation, effectively combat bureaucracy, and promote public self-realization of the individual. At the same time, wide direct participation in the management of insufficiently competent participants who are not responsible for their decisions, contradicts the social division of labor, reduces the effectiveness of management, complicates the rationalization of production. This can lead to the dominance of short-term interests over promising interests. Therefore, it is always important for society to find the optimal measure of a combination of self-management and professional management. It is determined that social representation acts, on the one hand, as the most important intermediary between the state and the population, the protection of social interests in a politically heterogeneous environment. On the other hand, it ensures the operation of a mechanism for correcting the political system, which makes it possible to correct previously adopted decisions in a legitimate way, without resorting to violence. It is proved that the system of social representation influences the most important political relations, promotes social integration, that is, the inclusion of various social groups and public associations in the political system. It is proposed to use the term “self-government” in relation to several levels of people’s association: the whole community — public self-government or self-government of the people, to individual regions or communities — local, to production management — production self-government. Traditionally, self-government is seen as an alternative to public administration. Ideology and practice of selfgovernment originate from the primitive, communal-tribal democracy. It is established that, in practice, centralization has become a “natural form of government”. In its pure form, centralization does not recognize the autonomy of places and even local life. It is characteristic of authoritarian regimes, but it is also widely used by democratic regimes, where they believe that political freedoms should be fixed only at the national level. It is determined that since the state has achieved certain sizes, it is impossible to abandon the admission of the existence of local authorities. Thus, deconcentration appears as one of the forms of centralization and as a cure for the excesses of the latter. Deconcentration assumes the presence of local bodies, which depend on the government functionally and in the order of subordination of their officials. The dependency of officials means that the leadership of local authorities is appointed by the central government and may be displaced.


2016 ◽  
Vol 1 (1) ◽  
Author(s):  
D.G. Shah ◽  
D.N. Mehta ◽  
R.V. Gujar

Bryophytes are the second largest group of land plants and are also known as the amphibians of the plant kingdom. 67 species of bryophytes have been reported from select locations across the state of Gujrat. The status of family fissidentaceae which is a large moss family is being presented in this paper. Globally the family consists of 10 genera but only one genus, Fissidens Hedw. has been collected from Gujarat. Fissidens is characterized by a unique leaf structure and shows the presence of three distinct lamina, the dorsal, the ventral and the vaginant lamina. A total of 8 species of Fissidens have been reported from the state based on vegetative characters as no sporophyte stages were collected earlier. Species reported from the neighboring states also showed the absence of sporophytes. The identification of different species was difficult due to substantial overlap in vegetative characters. Hence a detailed study on the diversity of members of Fissidentaceae in Gujarat was carried out between November 2013 and February 2015. In present study 8 distinct species of Fissidens have been collected from different parts of the state. Three species Fissidens splachnobryoides Broth., Fissidens zollingerii Mont. and Fissidens curvato-involutus Dixon. have been identified while the other five are still to be identified. Fissidens zollingerii Mont. and Fissidens xiphoides M. Fleisch., which have been reported as distinct species are actually synonyms according to TROPICOS database. The presence of sexual reproductive structures and sporophytes for several Fissidens species are also being reported for the first time from the state.


2015 ◽  
Vol 4 (3) ◽  
Author(s):  
Vinay Chauhan ◽  
Sushma Kaushal

Environmental scanning yields greater anticipatory management that provides important inputs for aquitision and use of information for planning and designing organization strategies. Apart from this, effective environmental scanning activities are likely to deal with threats and grasp the opportunities to finally link with enhancing organizational effectiveness. In fact this relationship matrix has led the researchers to conduct an environmental scanning through an examination of the existing status the components of the macro-environment vis-a-vis their relationship with the organizational effectiveness. There are a number of approaches, which describe the macro-environment, of which PEST analysis is regarded as the most common approach for considering the external business environment. Thus, the present study applies PEST analysis to scan the existing business environment. Jammu and Kashmir due to its peculiar political, geographical, economic, and socio-cultural features, had led its cost mountain economy become a distinctive identity. Despite the fact that the state has rich endowments, international relations with its neighbours vis-a-vis its impact on political environment also pose developmental challenges for the business units operating in the state. This has provided valid rationale for conducting the present. The environmental scanning is done through the perception of the select entrepreneurs operating MSMEs in the state of J & K. An impact analysis of environmental factors (PEST) on the organizational effectiveness is also done in the study. The findings of the study show that the political environment of the state that is not favourable for entrepreneural development whereas the rest of the other drivers of PEST i.e. economic environment, socio-cultural environment, and technological environment show a favourable response of the entrepreneurs. In terms of cause and effect relationship, it is found that the first two drivers of the PEST i.e. political and economic dimension impacts OE positively whereas the other two dimensions namely socio-cultural and technological impacts OE negatively but it is pertinent to mention that the impact is very less and is insigninificant. The study also suggests some of strategic options for developing and creating an enabling environment for successful entrepreneurial development to achieve integrated development of the state.


1987 ◽  
Vol 52 (10) ◽  
pp. 2482-2491 ◽  
Author(s):  
Ján Urban ◽  
Petr Kuzmič ◽  
David Šaman ◽  
Milan Souček

Anaerobic photolysis of dimethoxynitrobiphenyls IIIa-VIa in aqueous alkaline tert-butanol gave products of nucleophilic photosubstitution of methoxyl by hydroxide anion, while the dimethoxybiphenyls Ia and IIa were found unreactive. Regioselectivity of the reaction was examined in view of a possible “extended meta activation” by the nitro group. The most reactive substrate IIIa gives both C-3 and C-4 substitution products with an unsubstantial preference for the latter, which opposes the “extended meta selectivity” rule. All of the other compounds obey the rule, and 3,4-dimethoxy-3'-nitrobiphenyl (IVa) even displayed absolute selectivity by yielding C-3 substituted compound as the only product. 2,5-Dimethoxy substituted compounds underwent photosubstitution which much lower quantum yields than their 3,4-substituted counterparts, most probably due to some steric hindrance of conjugation. Similarly, 3-nitro-substituted biphenyls exhibited much lower overall reactivity than 4-nitro derivatives.


Author(s):  
Clive Holes

The vocabulary of the modern Gulf Arabic dialects contains many items of ancient Mesopotamian origin; there is also evidence of early south Arabian influences. Historically, three dialect types existed in the region: Najdi, coastal (these two are ‘A dialects’), and Baḥārna (‘B’ dialects). There must long have been contact between these three, but the main interface was between the Najdi and the coastal type. The (Shīˁī) Baḥārna lived in separate settlements, pursued livelihoods specific to them, and did not marry with the other two groups. All of this preserved their dialect. This sociolinguistic division was most evident in the state of Bahrain. In recent decades, changes in employment and increased urbanization have brought about increased interdialectal contact, resulting in the loss of B dialect features and a homogenization of the A dialects to the point that one can now speak of the emergence of a Gulf koine.


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