The recycled cathode ray tube(CRT)funnel glass was used as replacement of magnetite sand in the concrete,and its mass replacement rates were 0,20%,40%and 60%,respectively.The flowability,apparent density and mechanica...The recycled cathode ray tube(CRT)funnel glass was used as replacement of magnetite sand in the concrete,and its mass replacement rates were 0,20%,40%and 60%,respectively.The flowability,apparent density and mechanical properties of the radiation shielding concrete were investigated,while itsγ-ray radiation shielding parameters such as linear and mass attenuation coefficients(μandμm,respectively),thickness values of half-value layer(hHVL)and tenth-value layer(hTVL)were obtained by theoretical calculation,experiment and Monte.Carlo N-Particle(MCNP)simulation code.The experimental results show that the flowability of the concrete increases significantly,whilst its apparent density,compressive strength and static elastic modulus decrease slightly.The calculated,simulated and experimentalμm,μ,hHVL and hTVL values of all concrete samples are very consistent at the sameγ-ray photon energy,and it is feasible to use MCNP code to simulateγ-ray radiation shielding parameters of materials.The calculated results show that in a wide range ofγ-ray photon energy,theμm value of the concrete with CRT funnel glass replacing magnetite sand is improved effectively,and its radiation shielding performances are the same as those of the control concrete(M.1).By comprehensively comparing the flowability,mechanical properties andγ-ray radiation shielding properties,the concrete samples with 20%.40%funnel glass as fine aggregate have good performances.展开更多
In this paper we have reported a simple and cost effective lab level experiment to determine the revolution of DC motor at various voltages.This experiment is designed on the basis of laser light pulses observed in ca...In this paper we have reported a simple and cost effective lab level experiment to determine the revolution of DC motor at various voltages.This experiment is designed on the basis of laser light pulses observed in cathode ray oscilloscope(CRO)output through an aperture.These output waveforms are directly related with the revolution of DC motor.A laser light beam was allowed to pass through a slot attached with the shaft of DC motor.The outcoming light is in the form of light pulses that falls on the photodetector which was connected to CRO.The frequency of light pulses is the function of applied voltage to DC motor.The CRO output was measured at different voltages.The visual waveforms on CRO interpret the different values of revolutions per minute(rpm)at different values of voltages given to DC motor.Analysis was made to determine the voltage depended revolution.展开更多
We experimentally demonstrate all-optical clock recovery for 100 Gb/s return-to-zero on-off keying signals based on a monolithic dual-mode distributed Bragg reflector （DBR） laser, which can realize both mode spacing...We experimentally demonstrate all-optical clock recovery for 100 Gb/s return-to-zero on-off keying signals based on a monolithic dual-mode distributed Bragg reflector （DBR） laser, which can realize both mode spacing and wavelength tuning. By using a coherent injection locking scheme, a 100 GHz optical clock can be recovered with a timing jitter of 530 fs, which is derived by an optical sampling oscilloscope from both the phase noise and the power fluctuation. Furthermore, for degraded injection signals with an optical signal-to-noise ratio as low as 4.1 dB and a 25 km long distance transmission, good-quality optical clocks are all successfully recovered.展开更多
基金Project(14JJ2083)supported by the Natural Science Foundation of Hunan Province,ChinaProject(2015JC3090)supported by the Science and Technology Department of Hunan Province,China
文摘The recycled cathode ray tube(CRT)funnel glass was used as replacement of magnetite sand in the concrete,and its mass replacement rates were 0,20%,40%and 60%,respectively.The flowability,apparent density and mechanical properties of the radiation shielding concrete were investigated,while itsγ-ray radiation shielding parameters such as linear and mass attenuation coefficients(μandμm,respectively),thickness values of half-value layer(hHVL)and tenth-value layer(hTVL)were obtained by theoretical calculation,experiment and Monte.Carlo N-Particle(MCNP)simulation code.The experimental results show that the flowability of the concrete increases significantly,whilst its apparent density,compressive strength and static elastic modulus decrease slightly.The calculated,simulated and experimentalμm,μ,hHVL and hTVL values of all concrete samples are very consistent at the sameγ-ray photon energy,and it is feasible to use MCNP code to simulateγ-ray radiation shielding parameters of materials.The calculated results show that in a wide range ofγ-ray photon energy,theμm value of the concrete with CRT funnel glass replacing magnetite sand is improved effectively,and its radiation shielding performances are the same as those of the control concrete(M.1).By comprehensively comparing the flowability,mechanical properties andγ-ray radiation shielding properties,the concrete samples with 20%.40%funnel glass as fine aggregate have good performances.
文摘In this paper we have reported a simple and cost effective lab level experiment to determine the revolution of DC motor at various voltages.This experiment is designed on the basis of laser light pulses observed in cathode ray oscilloscope(CRO)output through an aperture.These output waveforms are directly related with the revolution of DC motor.A laser light beam was allowed to pass through a slot attached with the shaft of DC motor.The outcoming light is in the form of light pulses that falls on the photodetector which was connected to CRO.The frequency of light pulses is the function of applied voltage to DC motor.The CRO output was measured at different voltages.The visual waveforms on CRO interpret the different values of revolutions per minute(rpm)at different values of voltages given to DC motor.Analysis was made to determine the voltage depended revolution.
基金supported by the National 973 Program of China(Nos.2011CB301702 and 2011CB301703)the National Natural Science Foundation of China(Nos.61201103,61335009,and 61321063)
文摘We experimentally demonstrate all-optical clock recovery for 100 Gb/s return-to-zero on-off keying signals based on a monolithic dual-mode distributed Bragg reflector （DBR） laser, which can realize both mode spacing and wavelength tuning. By using a coherent injection locking scheme, a 100 GHz optical clock can be recovered with a timing jitter of 530 fs, which is derived by an optical sampling oscilloscope from both the phase noise and the power fluctuation. Furthermore, for degraded injection signals with an optical signal-to-noise ratio as low as 4.1 dB and a 25 km long distance transmission, good-quality optical clocks are all successfully recovered.
