Growth of cadmium sulfide (CdS) thin films on glass substrates was carried out by atmospheric pressure metal-organic chemical vapor deposition (AP-MOCVD) using Cd(S2CNEt2)2 as the single precursor. Changes in th...Growth of cadmium sulfide (CdS) thin films on glass substrates was carried out by atmospheric pressure metal-organic chemical vapor deposition (AP-MOCVD) using Cd(S2CNEt2)2 as the single precursor. Changes in the surface morphology of the deposited CdS thin films were investigated by atomic force microscope (AFM) as the function of substrate temperature (Ts), vaporizing temperature (Tv), and Ar flow rate. With the increase of Tv, CdS thin films evolved from pyramidal structure with fine grains to columnar structure with large grains. X-ray diffraction (XRD) patterns indicated that the CdS films had random orientation at the lower Tv and preferred orientation at the higher Tv. In addition, Ts had a great effect on the surface roughness of the CdS films, and a quantum dot-like structural CdS films were obtained in a narrow range of Ts with high Ar flow rate. Furthermore, the optical properties of the CdS films were measured using ultraviolet-visible (UV/VIS) spectrometer.展开更多
( CdS/ TiO2 )/ MCM-41 loaded nanometer photocatalyst was prepared by the sol-gel method and dipping process, the photocatalytic degradation of methyl thionine chloride in water was investigated by using the photocat...( CdS/ TiO2 )/ MCM-41 loaded nanometer photocatalyst was prepared by the sol-gel method and dipping process, the photocatalytic degradation of methyl thionine chloride in water was investigated by using the photocatalyst. The experimental results show that the optimum concentration of CdS over TiO2 was 3% ( molar ratio ), the photocatalytic activity was enhanced when making TiO2 the anatase ptase with a rise of the roasting temperature, and the carrier, mesoporous molecular sieve MCM-41, was beneficial to improving the photocatalytic activity of TiO2 for photocatalytic degradation of methyl thionine chloride. The morphology and the crystalline phase of the photocatalyst were discussed by means of XRD and SEM techniques, and the reaction mechanism of catalytic properties was also discussed.展开更多
Hydrogen energy has been regarded as the most promising energy resource in the near future due to that it is a clean and sustainable energy. And the heterogeneous photocatatytic hydrogen production is increasingly bec...Hydrogen energy has been regarded as the most promising energy resource in the near future due to that it is a clean and sustainable energy. And the heterogeneous photocatatytic hydrogen production is increasingly becoming a research hotspot around the world today. As visible light response photocatalysts for hydrogen production, cadmium sulfide (CdS) is the most representative material, the research of which is of continuing popularity. In the past several years, there has been significant progress in water splitting on CdS-based photocatalysts using solar light, especially in the develop- ment of co-catalysts. In this paper, recent researches into photocatalytic water splitting on CdS-based photocatalysts are reviewed, including controllable synthesis of CdS, modifications with different kinds of cocatalysts, solid solution, intercalated with layered nanocomposites and metal oxides, and hybrids with graphenes etc. Finally, the problems and future challenges in photocatalytic water splitting on CdS-based photocatalysts are described.展开更多
A hyperbolic function is introduced to reflect the attenuation effect of one firm's default to its partner. If two firms are competitors (copartners), the default intensity of one firm will decrease (increase) ab...A hyperbolic function is introduced to reflect the attenuation effect of one firm's default to its partner. If two firms are competitors (copartners), the default intensity of one firm will decrease (increase) abruptly when the other firm defaults. As time goes on, the impact will decrease gradually until extinct. In this model, the joint distribution and marginal distributions of default times are derived by employing the change of measure, and the fair swap premium of a credit default swap (CDS) can be valued.展开更多
We study the counterparty risk for a credit default swap (CDS) in a regime-switching market driven by an underlying continuous-time Markov chain. We model the default dependence via some correlated Cox processes wit...We study the counterparty risk for a credit default swap (CDS) in a regime-switching market driven by an underlying continuous-time Markov chain. We model the default dependence via some correlated Cox processes with regime-switching shot noise intensities containing common shock. Under the proposed model, the general bilateral counterparty risk pricing formula for CDS contracts with the possibility of joint defaults is presented. Based on some expressions for the conditional Laplace transform of the integrated intensity processes, semi-analytical solution for the bilateral credit valuation adjustment (CVA) is derived. When the model parameters satisfy some conditions, explicit formula for the bilateral CVA at time 0 is also given.展开更多
We consider a two-dimensional reduced form contagion model with regime-switching interacting default intensities. The model assumes the intensities of the default times are driven by macro-economy described by a homog...We consider a two-dimensional reduced form contagion model with regime-switching interacting default intensities. The model assumes the intensities of the default times are driven by macro-economy described by a homogeneous Markov chain as well as the other default. By using the idea of 'change of measure' and some closed-form formulas for the Laplace transforms of the integrated intensity processes, we derive the two-dimensional conditional and unconditional joint distributions of the default times. Based on these results, we give the explicit formulas for the fair spreads of the first-to-default and second-to-default credit default swaps (CDSs) on two underlyings.展开更多
The contagion credit risk model is used to describe the contagion effect among different financial institutions. Under such a model, the default intensities are driven not only by the common risk factors, but also by ...The contagion credit risk model is used to describe the contagion effect among different financial institutions. Under such a model, the default intensities are driven not only by the common risk factors, but also by the defaults of other considered firms. In this paper, we consider a two-dimensional credit risk model with contagion and regime-switching. We assume that the default intensity of one firm will jump when the other firm defaults and that the intensity is controlled by a Vasicek model with the coefficients allowed to switch in different regimes before the default of other firm. By changing measure, we derive the marginal distributions and the joint distribution for default times. We obtain some closed form results for pricing the fair spreads of the first and the second to default credit default swaps (CDSs). Numerical results are presented to show the impacts of the model parameters on the fair spreads.展开更多
基金supported by the Project of Key Technologies Research & Development Programme of Chengdu under Grant No.06GGYB512GX-030
文摘Growth of cadmium sulfide (CdS) thin films on glass substrates was carried out by atmospheric pressure metal-organic chemical vapor deposition (AP-MOCVD) using Cd(S2CNEt2)2 as the single precursor. Changes in the surface morphology of the deposited CdS thin films were investigated by atomic force microscope (AFM) as the function of substrate temperature (Ts), vaporizing temperature (Tv), and Ar flow rate. With the increase of Tv, CdS thin films evolved from pyramidal structure with fine grains to columnar structure with large grains. X-ray diffraction (XRD) patterns indicated that the CdS films had random orientation at the lower Tv and preferred orientation at the higher Tv. In addition, Ts had a great effect on the surface roughness of the CdS films, and a quantum dot-like structural CdS films were obtained in a narrow range of Ts with high Ar flow rate. Furthermore, the optical properties of the CdS films were measured using ultraviolet-visible (UV/VIS) spectrometer.
基金Funded by Special Fund of Education Department of ShaanxiProvince(No.03JK144)
文摘( CdS/ TiO2 )/ MCM-41 loaded nanometer photocatalyst was prepared by the sol-gel method and dipping process, the photocatalytic degradation of methyl thionine chloride in water was investigated by using the photocatalyst. The experimental results show that the optimum concentration of CdS over TiO2 was 3% ( molar ratio ), the photocatalytic activity was enhanced when making TiO2 the anatase ptase with a rise of the roasting temperature, and the carrier, mesoporous molecular sieve MCM-41, was beneficial to improving the photocatalytic activity of TiO2 for photocatalytic degradation of methyl thionine chloride. The morphology and the crystalline phase of the photocatalyst were discussed by means of XRD and SEM techniques, and the reaction mechanism of catalytic properties was also discussed.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 20973110), the National Basic Research Program of China (No. 2009CN220000) and the international Cooperation Project of Shanghai Municipal Science and Technology Commission (No. 12160705700).
文摘Hydrogen energy has been regarded as the most promising energy resource in the near future due to that it is a clean and sustainable energy. And the heterogeneous photocatatytic hydrogen production is increasingly becoming a research hotspot around the world today. As visible light response photocatalysts for hydrogen production, cadmium sulfide (CdS) is the most representative material, the research of which is of continuing popularity. In the past several years, there has been significant progress in water splitting on CdS-based photocatalysts using solar light, especially in the develop- ment of co-catalysts. In this paper, recent researches into photocatalytic water splitting on CdS-based photocatalysts are reviewed, including controllable synthesis of CdS, modifications with different kinds of cocatalysts, solid solution, intercalated with layered nanocomposites and metal oxides, and hybrids with graphenes etc. Finally, the problems and future challenges in photocatalytic water splitting on CdS-based photocatalysts are described.
基金the National Basic Research Program of China(973 Program)(No.2007CB814903)the National Natural Science Foundation of China(No.70671069)
文摘A hyperbolic function is introduced to reflect the attenuation effect of one firm's default to its partner. If two firms are competitors (copartners), the default intensity of one firm will decrease (increase) abruptly when the other firm defaults. As time goes on, the impact will decrease gradually until extinct. In this model, the joint distribution and marginal distributions of default times are derived by employing the change of measure, and the fair swap premium of a credit default swap (CDS) can be valued.
基金The authors thank the anonymous referees for valuable comments to improve the earlier version of the paper. The research of Yinghui Dong was supported by the Natural Science Foundation of Jiangsu Province (Grant No. BK20170064) and QingLan project. The research of Kam Chuen Yuen was supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. HKU17329216), and the CAE 2013 research grant from the Society of Actuaries-any opinions, finding, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the SOA. The research of Guojing Wang was supported by the National Natural Science Foundation of China (Grant No. 11371274).
文摘We study the counterparty risk for a credit default swap (CDS) in a regime-switching market driven by an underlying continuous-time Markov chain. We model the default dependence via some correlated Cox processes with regime-switching shot noise intensities containing common shock. Under the proposed model, the general bilateral counterparty risk pricing formula for CDS contracts with the possibility of joint defaults is presented. Based on some expressions for the conditional Laplace transform of the integrated intensity processes, semi-analytical solution for the bilateral credit valuation adjustment (CVA) is derived. When the model parameters satisfy some conditions, explicit formula for the bilateral CVA at time 0 is also given.
基金Acknowledgements The authors thank the anonymous referees for valuable comments to improve the earlier version of the paper. The research of Yinghui Dong was supported by the Natural Science Foundation of Jiangsu Province (Grant No. BK20130260), the National Natural Science Foundation of China (Grant No. 11301369), and the China Postdoctoral Science Foundation (Grant No. 2013M540371). The research of Guojing Wang was supported by the National Natural Science Foundation of China (Grant No. 11371274) and the Natural Science Foundation of Jiangsu Province (Grant No. BK2012613).
文摘We consider a two-dimensional reduced form contagion model with regime-switching interacting default intensities. The model assumes the intensities of the default times are driven by macro-economy described by a homogeneous Markov chain as well as the other default. By using the idea of 'change of measure' and some closed-form formulas for the Laplace transforms of the integrated intensity processes, we derive the two-dimensional conditional and unconditional joint distributions of the default times. Based on these results, we give the explicit formulas for the fair spreads of the first-to-default and second-to-default credit default swaps (CDSs) on two underlyings.
基金Acknowledgements The authors cordially thank the anonymous reviewers for valuable comments to improve the earlier version of the paper. This work was supported by the National Natural Science Foundation of China (Grant Nos. 11371274, 11671291), the Natural Science Foundation of Jiangsu Province (Grant No. BK20160300), and the Open Project of Jiangsu Key Laboratory of Financial Engineering (Grant No. NSK2015-05).
文摘The contagion credit risk model is used to describe the contagion effect among different financial institutions. Under such a model, the default intensities are driven not only by the common risk factors, but also by the defaults of other considered firms. In this paper, we consider a two-dimensional credit risk model with contagion and regime-switching. We assume that the default intensity of one firm will jump when the other firm defaults and that the intensity is controlled by a Vasicek model with the coefficients allowed to switch in different regimes before the default of other firm. By changing measure, we derive the marginal distributions and the joint distribution for default times. We obtain some closed form results for pricing the fair spreads of the first and the second to default credit default swaps (CDSs). Numerical results are presented to show the impacts of the model parameters on the fair spreads.