15 research outputs found
Effectiveness Evaluation of Financing Platform Operation of Buildings Energy Saving Transformation Using ANP-Fuzzy in China: An Empirical Study
Building energy saving transformation is an inevitable requirement to achieve sustainable development, which can bring considerable economic, environmental, and social benefits. The key to healthy development of the market lies in the orderly operation of the financing platform. The effectiveness of the financing platform depends on scientific evaluation. Therefore, it is necessary to design a set of systematic and practical evaluation indicators for operational effectiveness of the buildings energy saving transformation financing platform, so as to provide reference for the effective operation of the financing platform, and provide measurement means for scholars to conduct quantitative research on the financing platform. This paper analyzes the effectiveness evaluation content for the financing platform operation of buildings energy saving transformation from the two levels of operation mechanism and operation subject behavior. Combined with the particularity of the financing platform of building energy saving transformation, the operational effectiveness evaluation index system of the financing platform is designed from three levels. The Analytic Network Process (ANP) method is applied to construct network structure, to describe element correlation, and to calculate index weight. The fuzzy comprehensive evaluation (Fuzzy) method was used to carry out quantitative evaluation of qualitative indicators. The Energy Performance Contracting (EPC) financing platform in Beijing was taken as an example to make an empirical analysis. The results show that the operational effectiveness evaluation system of the financing platform of buildings energy saving transformation constructed in this paper has certain practicability. In this evaluation system, scores of target consistency, the degree of information sharing among departments and coordination of operation mechanism are low. Finally, some policy suggestions are put forward to optimize financing platform of buildings energy saving transformation in China
Transient behaviors of pulse breaking and recovering in a dispersion-managed mode-locked Yb fiber laser
Various pulse regimes have been discovered in mode-locked fiber lasers with carefully designed cavity setups. However, the transitions between different types of stable pulse solutions are rarely observed in a laser with the same cavity configuration. Here, we report on the experimental observation of the transformation from stretched pulses (SPs) to dissipative solitons (DSs) in an all-polarization-maintaining dispersion-managed mode-locked Yb fiber laser for the first time. By means of the time-stretch dispersive Fourier transform technique, the temporal and spectral dynamics of transient behaviors from pulse breaking to pulse recovering are identified in real time. It is revealed that the overdriven nonlinear effect induced by pump increase triggers the wave breaking of SPs, and the improved net-cavity dispersion originated from wavelength shift helps the self-recovering of DSs. Numerical simulations validate the experimental observations and bring insights to the understanding of transient nonlinear dynamics in ultrafast fiber lasers
Observation of Wavelength Tuning in a Mode-Locked Figure-9 Fiber Laser
We demonstrate an all-PM Er-doped soliton mode-locked fiber oscillator based on the figure-9 configuration with a compact adjustable reflection-type non-reciprocal phase shifter. An analytical model based on the Jones matrix is established to simulate the wavelength tuning phenomenon. Experimentally, it is observed that the increase in pump power results in a significant redshift in the spectrum of output pulses. When the angle of the half-wave plate is rotated in one direction, the output spectrum is redshifted and then blueshifted successively. Good qualitative agreement is presented between the simulations and the experimental results. It is shown that the increase in pump power changes the nonlinear phase shift, which causes the redshift of the transmittance curves at the laser output port. In contrast, the rotation of wave plates not only changes the nonlinear phase shift difference, but also causes variations in linear phase bias and modulation depth. The changes in these parameters lead to the redshift and blueshift of the transmission curves, which enables wavelength tuning
Observation of Wavelength Tuning in a Mode-Locked Figure-9 Fiber Laser
We demonstrate an all-PM Er-doped soliton mode-locked fiber oscillator based on the figure-9 configuration with a compact adjustable reflection-type non-reciprocal phase shifter. An analytical model based on the Jones matrix is established to simulate the wavelength tuning phenomenon. Experimentally, it is observed that the increase in pump power results in a significant redshift in the spectrum of output pulses. When the angle of the half-wave plate is rotated in one direction, the output spectrum is redshifted and then blueshifted successively. Good qualitative agreement is presented between the simulations and the experimental results. It is shown that the increase in pump power changes the nonlinear phase shift, which causes the redshift of the transmittance curves at the laser output port. In contrast, the rotation of wave plates not only changes the nonlinear phase shift difference, but also causes variations in linear phase bias and modulation depth. The changes in these parameters lead to the redshift and blueshift of the transmission curves, which enables wavelength tuning.