Understanding the underlying forces of China's climate governance, and assessing effectiveness institutions, are critical to global governance architecture. This paper reviews evolution system over past three decades, examines how factors such as socioeconomic transitions, cognitive shifts associated with change, well international politics have influenced institutions. We argue that is by varying dynamics between change Chinese state's quest for performance legitimacy. The positive...

A brominated flame retardant (BFR), hexabrominated heterocyclic tris-(2,3-dibromopropyl) isocyanurate (TBC), was identified, for the first time, in natural environment. The chemical found river water (2.33−163 ng/L), surface sediments (85.0 ng/g−6.03 μg/g dry weight (dw)), soils (19.6−672 ng/g dw), earthworm (9.75−78.8 and carp samples (12.0−646 dw) from a factory-polluted area southern China. It that TBC can strongly adsorb to organic material sediment, trend of decreasing concentration...

We demonstrate a 2.8 μm gas Raman laser in methane-filled hollow-core negative-curvature fiber with average power of 113 mW, pulse energy μJ and estimated peak 9.5 MW. quantum efficiency 40% has been reached from the pump source at 1.064 to 2nd order vibrational Stokes 2.812 using 1.8 MPa methane gas. To our knowledge, this is first high fiber-based mid-infrared region range applications supercontinuum generation, surgery, molecular tracing detection are prospect.

We study photothermal phase modulation in gas-filled hollow-core optical fibers with differential structural dimensions and attempt to develop highly sensitive practical gas sensors an in-line Fabry-Perot interferometer for detection of the modulation. Analytical formulations based on a hollow-capillary model are developed estimate amplitude at low frequencies as well -3 dB roll-off frequency, which provide guide selection pump maximize Numerical simulation capillary experiments two types...

We report for the first time multi-watt mid-infrared supercontinuum (SC) output from a dehydrated tellurite step-index fiber. The glass preform is melted in dry-atmosphere filled glovebox and water impurity has been reduced to 1ppm level. fiber large core diameter of 12 µm numerical aperture (NA) 0.21. Using amplified Raman-shifted soliton pulses 1.55 erbium-doped laser as pump, broadband 2-3 with 3dB bandwidth 985 nm generated an 80cm-long power spectral density SC above 3.5 dBm/nm whole...

Power scaling of broadband and narrowband thulium-doped all-fiber superfluorescent sources based on master-oscillator power-amplifier configuration is reported. For the output-power fiber source, a stable low-power seed source two-stage cladding-pumped amplifiers were adopted. The power amplifier yielded 122 W superfluorescence output, wavelength range spanned from 1935-2075 nm with full width at half maximum (FWHM) 25 nm. To best our knowledge, this first demonstration exceeding 100 2 μm....

We demonstrate a stable passively Q-switched and gain-switched Yb-doped all-fiber laser cladding-pumped by continuous fiber-coupled 976 nm diode. By use of an dual-cavity, the efficient elements mainly include fiber Bragg gratings rare-earth doped fiber, allowing oscillator to be integrated in compact size with reliable output. In this scheme, output 45 ns pulse width, 62 μJ energy, 1.4 kW peak power operating at 1081 was obtained. To best our knowledge, is minimum width similar kind...

We demonstrate generation of widely tunable femtosecond pulses by utilizing the soliton self-frequency shift effect in a Tm-doped fiber amplifier, seeded dispersion managed mode-locked Tm oscillator. The monochromatic with duration order 100 fs have been obtained and its wavelength can be adjusted continuously range 1.9-2.36 μm varying pump power. efficiency Raman conversion is as high 97% output power up to 1.16 W. experimental results are good agreement numerical simulations pulse...

The limited spectral bandwidth achieved in state-of-the-art hollow-core photonic bandgap fibers (HC-PBGF) has hindered its implementation a wide range of applications. Here we demonstrate that broad and low loss can be simultaneously 7-cell HC-PBGF. Several HC-PBGFs operating at 1550 nm telecom band 1 μm laser are present. One the exhibits minimum 6.5 dB/km 1633 3 dB 458 nm, approaching to central wavelength ratio 26%. This is our knowledge broadest triangular lattice HC-PBGF lowest transmission

Although the Ice, Cloud, and land Elevation Satellite/Geoscience Laser Altimetry System (ICESat/GLAS) has been used for urban monitoring, however, previous studies focused on extracting maximum building height within footprint. In fact, full-waveform recording of GLAS data makes it possible to extract multiple heights. However, uncertainty spatial distribution reflectance creates considerable challenges fine inversion heights this letter, we proposed an method using assisted by QuickBird...

The global digital elevation measurement (DEM) products such as SRTM DEM and GDEM have been widely used for terrain slope retrieval in forests. However, the estimation accuracy is generally limited due to DEMs’ low vertical over complex forest environments. Ice, Cloud, land Elevation Satellite-2 (ICESat-2) mission shows excellent potential because of high unique design beam pairs. This study aimed explore possibility ICESat-2 data United States First, raw were processed obtain accurate...

An Yb : YVO4 single crysal with good optical quality and large size has been grown by the Czochralski method. We have discussed growth shape of crystal which is composed {100} {101} simple forms. The data thermal expansion specific heat measured. coefficients along a- c-axis directions are α1 = 1.5 × 10—6/K α3 8.2 10—6/K, respectively. 30.4 cal/mol K at 320 K. absorption fluorescence spectra

We demonstrate a polarization-maintaining (PM) dual-wavelength (DW) single-frequency Er-doped distributed Bragg reflection (DBR) fiber laser with 28 GHz stable frequency difference. A homemade PM low-reflectivity superimposed grating (SFBG) is employed as the output port of DBR laser. The SFBG has two wavelengths located in same region. reflectivity both DWs around 85%. achieved linear polarization extinction ratio more than 20 dB. are at 1552.2 nm and 1552.43 nm, respectively. optical...

We investigated the frequency noise coupling mechanism of a 2 μ m polarization-maintaining single fiber laser (SFFL) theoretically and experimentally. The pump’s relative intensity (RIN) to single-frequency high-gain silica is shown experimentally be consistent with theoretical model where thermal expansion thermo-optic effect mediate coupling. measured SFFL three pump sources compared. find using 1550 nm source produces lowest noise, less than 100 <mml:math...

Abstract Accurate evaluation of evapotranspiration ( ET ) is crucial for efficient agricultural water management. Data‐driven models exhibit strong predictive capabilities, yet significant limitations like naive extrapolation hamper wider generalization. In this perspective, we explore a novel hybrid deep learning DL framework to integrate domain knowledge and demonstrate its potential evaluating under the influence soil salinity. Specifically, integrated physical constraints from process...

We investigate the stimulated Brillouin scattering (SBS) effect in high-power thulium-doped fiber amplifier seeded with a narrow-linewidth superfluorescent source or conventional laser. No random backward SBS pulses are observed when using as seed. The corresponding average power and peak reach 153 W 3.4 kW, respectively, only limited by available pump power. This gives extraction from 17 fold enhancement, comparison situation laser similar central wavelength spectral linewidth work...

Attitude jitter is a problem commonly experienced by remote-sensing satellites, and deteriorates the accuracy of geo-positioning mapping. Therefore, it important to design method which can handle this problem. This paper presents compensation using compressive sampling. In method, influence attitude in imagery represented two fluctuating signals, are called distortion signals paper. Using sampling, be estimated with small set ground control points (GCPs). Based on we conduct affected jitter....

As an essential parameter in forestry, crown base height (CBH) faces many tasks. The methods are still developing for estimating it. Unmanned aerial vehicles (UAVs) light detection and ranging (LiDAR) supplies new, massive, high-density data CBH. Many had been generated to compute CBH indirectly using regression-based ways or directly geometric/statistical LiDAR-based ways. However, there were few deal with the problem of understory, trunk, noise points caused by UAV data. A robust method...