RESUMO
Two kinds of 1 W white high power light emitting diode (LED) were made by packaging blue chips from Taiwan and US. The chips were coated by the same phosphor and transparent silica gel. Optical properties of the two kinds of LEDs were investigated in the temperature range of 15-75 degrees C and at the current of 350 mA. The results show that temperature badly affects the optical parameters such as peak wavelength, radiant flux, color temperature and so on. After analyzing the PL spectrum, the relationship between temperature and LED performance was found. The reasons for optical parameters vs. temperature were theoretically analyzed. Some suggestions were given to reduce the influence of temperature on power LED.
RESUMO
White powder light emitting diodes (LED) with different color temperature were made by using different ratio of yellow to orange silicate phosphor. When the ratio of yellow to orange phosphor was less than 7, the peak wavelength of yellow light in spectra was about 570 nm and the wavelength was about 590 nm as the ratio was greater than 7. With the color temperature increasing, the color rendering index and the luminous efficiency increased at the beginning and then decreased. And color temperature of 5 521 K is the optimal value. The reason was the ineffective excitation of blue light due to higher concentration of phosphor and excess red light in spectra. In contrast, blue light was not excited effectively and red light in spectra was little when the color temperature was higher than 5 521 K. The luminous efficiency was decreased, and the decreased magnitude was inconsistency with the testing temperature from 10 to 80 degrees C. This suggests that, besides Auger recombination, the decrease in excitation efficiency of yellow and orange phosphors is different as the temperature rises and orange phosphor's temperature characteristic is superior to that of yellow phosphor.
RESUMO
OBJECTIVE: To investigate the immune protection of the recombinant membrane protein(45M) against larvae of Taenia multiceps in sheep. METHODS: Twelve sheep were randomly divided into immune group and control group, and each sheep was immunized four times (three weeks interval) respectively with 50 microg recombinant 45M or GST emulsified with adjuvant. Serum samples were collected at pre-immunization and certain time after immunization, and were analyzed for IgG and IgM by ELISA. At the 105th day after the final inoculation, each sheep was orally challenged by 5000 eggs of T. multiceps. Two weeks after infection, the sheep were sacrificed, serum samples were collected, and number of cysts in brain tissue was counted. Activated oncospheres were cultured with 10% sera of immune group or control group, and observed by light microscopy. RESULTS: The mean number of cysts was 1.5, and the average diameter of the cysts was 2.2 mm. Compared with control group, the reduction rate of cysts in immunized sheep was 68.9%. At the 72th hour after culture with serum of immunized sheep, about 90% oncospheres were killed by antiserum, and the oncospheres began to shrink or expand, and internal structure became fuzzy. ELISA showed that after final immunization (the 9th week), the levels of IgG in sera of immune group (2.32+/-0.76) were significantly higher than those of the control (0.70+/-0.42) (t=4.47, P<0.01). At the 24th week the levels of IgG and IgM in sera of immune group (1.53+/- 0.81, 0.90+/-0.26) were significantly higher than those of the control (0.64+/-0.43, 0.43+/-0.15) (P<0.01). CONCLUSION: The recombinant 45M can induce certain humoral immune response.
