The technology of He ion implantation for improving the catastrophic optical damage (COD) level of 980nm semiconductor lasers is introduced.After He ion implantation,p-GaAs obtain higher resistivity than before.About...The technology of He ion implantation for improving the catastrophic optical damage (COD) level of 980nm semiconductor lasers is introduced.After He ion implantation,p-GaAs obtain higher resistivity than before.About 25μm-long current non-injection regions are introduced near both facets,where the injection current is blocked by high resistivity area.The current non-injection regions can reduce carriers inject to facets,and the rate of the non-radiative recombination are reduced.So the COD level is higher than before.The He ion implantation LDs exhibit no COD failure until the rollover occure at a mean maximum power of 440.5mW.Mean COD level of conventional LDs is given as 407.5mW.Compared to conventional LDs,the mean maximum output power level of He ion implantation LDs is improved by 8%.展开更多
For a special class of non-injective maps on Riemannian manifolds an upper bound for the fractal dimension of invariant set in terms of singular values of the tangent map and degree of non-injectivity is given.
The aim of the current study was to examine the prevalence of HIV, past six-month illicit drug use, and risk behaviors among a population of heavy drug users living in an urban setting. Although many studies investiga...The aim of the current study was to examine the prevalence of HIV, past six-month illicit drug use, and risk behaviors among a population of heavy drug users living in an urban setting. Although many studies investigate substance use, sex-risk behavior, and HIV by race and gender, no studies have examined these variables simultaneously. The current study seeks to fill this gap in the literature by exploring HIV prevalence among a predominantly heterosexual sample of recent substance users by injection drug use (IDU) status, race, and sex. Baseline data from the Baltimore site of the NEURO-HIV epidemiologic study was used in this study. This study examines neuropsychological and social-behavioral risk factors of HIV, hepatitis A, hepatitis B, and hepatitis C among both injection and non-injection drug users. Descriptive statistics and chi-square statistics were used in data analyses. Blood and urine samples were obtained to test for the presence of recent drug use, viral hepatitis, HIV, and other sexually transmitted diseases (STDs). Findings presented here have several important implications for HIV prevention and care among substance users. Intervention programs that incorporate substance use treatment in addition to HIV education, particularly with respect to substance use and sex risk behavior are imperative.展开更多
Family 373 and 406 of CdS magic-sized nanocrystals （MSNCs） were synthesized by a one-pot non-injection approach and white-light emission was generated from the coexistence of them. This light had excellent color cha...Family 373 and 406 of CdS magic-sized nanocrystals （MSNCs） were synthesized by a one-pot non-injection approach and white-light emission was generated from the coexistence of them. This light had excellent color characteristics, as defined by their pure white CIE （Commission International de l＇Eclairage） color coordinates （0.328, 0.343）, and it correlated with a color temperature of 5696 K. A probable thermodynamic equilibrium was proposed to explain the white-light emission behavior in this letter.展开更多
文摘The technology of He ion implantation for improving the catastrophic optical damage (COD) level of 980nm semiconductor lasers is introduced.After He ion implantation,p-GaAs obtain higher resistivity than before.About 25μm-long current non-injection regions are introduced near both facets,where the injection current is blocked by high resistivity area.The current non-injection regions can reduce carriers inject to facets,and the rate of the non-radiative recombination are reduced.So the COD level is higher than before.The He ion implantation LDs exhibit no COD failure until the rollover occure at a mean maximum power of 440.5mW.Mean COD level of conventional LDs is given as 407.5mW.Compared to conventional LDs,the mean maximum output power level of He ion implantation LDs is improved by 8%.
文摘For a special class of non-injective maps on Riemannian manifolds an upper bound for the fractal dimension of invariant set in terms of singular values of the tangent map and degree of non-injectivity is given.
文摘The aim of the current study was to examine the prevalence of HIV, past six-month illicit drug use, and risk behaviors among a population of heavy drug users living in an urban setting. Although many studies investigate substance use, sex-risk behavior, and HIV by race and gender, no studies have examined these variables simultaneously. The current study seeks to fill this gap in the literature by exploring HIV prevalence among a predominantly heterosexual sample of recent substance users by injection drug use (IDU) status, race, and sex. Baseline data from the Baltimore site of the NEURO-HIV epidemiologic study was used in this study. This study examines neuropsychological and social-behavioral risk factors of HIV, hepatitis A, hepatitis B, and hepatitis C among both injection and non-injection drug users. Descriptive statistics and chi-square statistics were used in data analyses. Blood and urine samples were obtained to test for the presence of recent drug use, viral hepatitis, HIV, and other sexually transmitted diseases (STDs). Findings presented here have several important implications for HIV prevention and care among substance users. Intervention programs that incorporate substance use treatment in addition to HIV education, particularly with respect to substance use and sex risk behavior are imperative.
文摘Family 373 and 406 of CdS magic-sized nanocrystals （MSNCs） were synthesized by a one-pot non-injection approach and white-light emission was generated from the coexistence of them. This light had excellent color characteristics, as defined by their pure white CIE （Commission International de l＇Eclairage） color coordinates （0.328, 0.343）, and it correlated with a color temperature of 5696 K. A probable thermodynamic equilibrium was proposed to explain the white-light emission behavior in this letter.
