Essential role of composting industry in achieving China's dual-carbon goals: Case studies from Chinese composting companies.

Composting is one of the primary methods for organic waste recycling in China. This study aims to analyze the product quality of organic fertilizer enterprises from the perspective of actual production and the relationship between production process variations and organic matter content in organic fertilizers based on 348 samples from 229 organic fertilizer companies across 22 provinces. Results showed that fertilizers produced through composting processes contain higher organic matter, averaging 45.

Effects of aeration modes and rates on nitrogen conversion and bacterial community in composting of dehydrated sludge and corn straw.

Aeration is an important factor to regulate composting efficiency and nitrogen loss. This study is aimed to compare the effects of different aeration modes (continuous and intermittent) and aeration rate on nitrogen conversion and bacterial community in composting from dehydrated sludge and corn straw. Results showed that the intermittent aeration mode at same aeration volume was superior to the continuous aeration mode in terms of NH emission reduction, nitrogen conversion and germination index (GI) improvement.

Optimization of coupling crop and livestock production system's eco-efficiency in northern China based on a life cycle assessment and data envelopment analysis method.

Under the twin pressures of global food security and dual‑carbon strategies, improving farm eco-efficiency is critical for achieving China's goal of a 50 Pg increase in grain production, meeting the ambitious climate mitigation targets set by the Paris Agreement, and meeting seven of the seventeen Sustainable Development Goals (SDGs) set by the United Nations. However, there is limited research on eco-efficiency measures supported by localised fine-scale data and coupling mechanisms for the structure, production process, efficiency improvement, and carbon reduction synergies of integrated farming systems in China. This study used the Life Cycle Assessment (LCA) and Data Envelopment Analysis (DEA) methods to assess eco-efficiency at the farm level in northern China, included in the National Coupling Crop and Livestock Production Pilot Programs, to improve the eco-efficiency of farms to achieve increased production and emission reductions.

Synergistic effects of chemical additives and mature compost on reducing HS emission during kitchen waste composting.

Additives could improve composting performance and reduce gaseous emission, but few studies have explored the synergistic of additives on HS emission and compost maturity. This research aims to make an investigation about the effects of chemical additives and mature compost on HS emission and compost maturity of kitchen waste composting. The results showed that additives increased the germination index value and HS emission reduction over 15 days and the treatment with both chemical additives and mature compost achieved highest germination index value and HS emission reduction (85%).

Fabricating and investigating a beveled mesa with a specific inclination angle to improve electrical and optical performances for GaN-based micro-light-emitting diodes.

In this Letter, beveled mesas for 30 × 30 µm GaN-based micro-light-emitting diodes (µLEDs) with different inclination angles are designed, fabricated, and measured. We find that µLED with a mesa inclination angle of 28° has the lowest internal quantum efficiency (IQE) and the highest injection current density at which the peak IQE is obtained. This is due to the increased quantum confined Stark effect (QCSE) at the mesa edge.

Lattice-matched AlInN/GaN bottom DBR impact on GaN-based vertical-cavity-surface-emitting laser diodes: systematical investigations.

In this paper, by using advanced numerical models, we investigate the impact of the AlN/GaN distributed Bragg reflector (DBR) and AlInN/GaN DBR on stimulated radiative recombination for GaN-based vertical-cavity-surface-emitting lasers (VCSELs). According to our results, when compared with the VCSEL with AlN/GaN DBR, we find that the VCSEL with AlInN/GaN DBR decreases the polarization-induced electric field in the active region, and this helps to increase the electron-hole radiative recombination. However, we also find that the AlInN/GaN DBR has a reduced reflectivity when compared with the AlN/GaN DBR with the same number of pairs.

Chemical-Mechanical Robustness of Single-Crystalline Ni-Rich Cathode Enabled by Surface Atomic Arrangement Control.

Layered transition metal oxide cathodes have been one of the dominant cathodes for lithium-ion batteries with efficient Li intercalation chemistry. However, limited by the weak layered interaction and unstable surface, mechanical and chemical failure plagues their electrochemical performance, especially for Ni-rich cathodes. Here, adopting a simultaneous elemental-structural atomic arrangement control based on the intrinsic Ni-Co-Mn system, the surface role is intensively investigated.

Size controllable single-crystalline Ni-rich cathodes for high-energy lithium-ion batteries.

A single-crystalline Ni-rich (SCNR) cathode with a large particle size can achieve higher energy density, and is safer, than polycrystalline counterparts. However, synthesizing large SCNR cathodes (>5 μm) without compromising electrochemical performance is very challenging due to the incompatibility between Ni-rich cathodes and high temperature calcination. Herein, we introduce Vegard's Slope as a guide for rationally selecting sintering aids, and we successfully synthesize size-controlled SCNR cathodes, the largest of which can be up to 10 μm.

Suppressing optical crosstalk for GaN/InGaN based flip-chip micro light-emitting diodes by using an air-cavity patterned sapphire substrate as a light filter.

In this work, by using three-dimensional finite-difference time-domain (3D FDTD) method, the effect of conventional nano-patterned sapphire substrate (NPSS) on the optical crosstalk and the light extraction efficiency (LEE) for InGaN/GaN-based flip-chip micro light-emitting diodes (µ-LEDs) are systematically studied. We find that the conventional NPSS is not suitable for µ-LEDs. It is because the inclined mesa sidewall for µ-LEDs possesses a good scattering effect for µ-LEDs, but the introduced conventional NPSS causes part of the light be off escape cone between sapphire and air and become the guided light.

On the impact of the beveled mesa for GaN-based micro-light emitting diodes: electrical and optical properties.

In this report, the impact of different mesa designs on the optical and electrical characteristics for GaN-based micro-light emitting diodes (µLEDs) has been systematically and numerically investigated by using TCAD simulation tools. Our results show that an enhanced light extraction efficiency can be obtained by using beveled mesas. The inclined mesa angles can more effectively reflect the photons to the substrate, and this helps to extract the photons to free air for flip-chip µLEDs.

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Single-crystalline Ni-rich cathodes with high capacity have drawn much attention for mitigating cycling and safety crisis of their polycrystalline analogues. However, planar gliding and intragranular cracking tend to occur in single crystals with cycling, which undermine cathode integrity and therefore cause capacity degradation. Herein, we intensively investigate the origin and evolution of the gliding phenomenon in single-crystalline Ni-rich cathodes.

Precision Feeding in Ecological Pig-Raising Systems with Maize Silage.

Ecological pig-raising systems (EPRSs) differ from conventional breeding systems, focusing more on environmental consequences, human health, and food safety during production processes. Thus productions from EPRSs have undergone significant development in China. Thus far, adding plant fiber sources (e.

An Air-Stable High-Nickel Cathode with Reinforced Electrochemical Performance Enabled by Convertible Amorphous Li CO Modification.

High-nickel (Ni ≥ 90%) cathodes with high specific capacity hold great potential for next-generation lithium-ion batteries (LIBs). However, their practical application is restricted by the high interfacial reactivity under continuous air erosion and electrolyte assault. Herein, a stable high-nickel cathode is rationally designed via in situ induction of a dense amorphous Li CO on the particle surface by a preemptive atmosphere control.

Artificially formed resistive ITO/p-GaN junction to suppress the current spreading and decrease the surface recombination for GaN-based micro-light emitting diodes.

Due to the increased surface-to-volume ratio, the surface recombination caused by sidewall defects is a key obstacle that limits the external quantum efficiency (EQE) for GaN-based micro-light-emitting diodes (µLEDs). In this work, we propose selectively removing the periphery p-GaN layer so that the an artificially formed resistive ITO/p-GaN junction can be formed at the mesa edge. Three types of LEDs with different device dimensions of 30 × 30 µm, 60 × 60 µm and 100 × 100 µm are investigated, respectively.

Is a thin p-GaN layer possible for making high-efficiency AlGaN-based deep-ultraviolet light-emitting diodes?

In this report, we investigate the impact of a thin p-GaN layer on the efficiency for AlGaN-based deep-ultraviolet light-emitting diodes (DUV LEDs). According to our results, the light extraction efficiency (LEE) becomes higher with the decrease of the p-GaN layer thickness, which can be ascribed to the decreased absorption of DUV emission by the thin p-GaN layer. Moreover, we also find that the variation trend of external quantum efficiency (EQE) is consistent with that of LEE.

Mitigating the Kinetic Hindrance of Single-Crystalline Ni-Rich Cathode via Surface Gradient Penetration of Tantalum.

Single-crystalline Ni-rich cathodes are promising candidates for the next-generation high-energy Li-ion batteries. However, they still suffer from poor rate capability and low specific capacity due to the severe kinetic hindrance at the nondilute state during Li intercalation. Herein, combining experiments with density functional theory (DFT) calculations, we demonstrate that this obstacle can be tackled by regulating the oxidation state of nickel via injecting high-valence foreign Ta .

Step-type quantum wells with slightly varied InN composition for GaN-based yellow micro light-emitting diodes.

In this work, we propose adopting step-type quantum wells to improve the external quantum efficiency for GaN-based yellow micro light-emitting diodes. The step-type quantum well is separated into two parts with slightly different InN compositions. The proposed quantum well structure can partially reduce the polarization mismatch between quantum barriers and quantum wells, which increases the overlap for electron and hole wave functions without affecting the emission wavelength.

Bridging Interparticle Li Conduction in a Soft Ceramic Oxide Electrolyte.

Li-conductive ceramic oxide electrolytes, such as garnet-structured LiLaZrO have been considered as promising candidates for realizing the next-generation solid-state Li-metal batteries with high energy density. Practically, the ceramic pellets sintered at elevated temperatures are often provided with high stiffness yet low fracture toughness, making them too brittle for the manufacture of thin-film electrolytes and strain-involved operation of solid-state batteries. The ceramic powder, though provided with ductility, does not yield satisfactorily high Li conductivity due to poor ion conduction at the boundaries of ceramic particles.

Alternative Strategy to Reduce Surface Recombination for InGaN/GaN Micro-light-Emitting Diodes-Thinning the Quantum Barriers to Manage the Current Spreading.

Owing to high surface-to-volume ratio, InGaN-based micro-light-emitting diodes (μLEDs) strongly suffer from surface recombination that is induced by sidewall defects. Moreover, as the chip size decreases, the current spreading will be correspondingly enhanced, which therefore further limits the carrier injection and the external quantum efficiency (EQE). In this work, we suggest reducing the nonradiative recombination rate at sidewall defects by managing the current spreading effect.

Enhancing the lateral current injection by modulating the doping type in the p-type hole injection layer for InGaN/GaN vertical cavity surface emitting lasers.

In this report, we propose GaN-based vertical cavity surface emitting lasers with a p-GaN/n-GaN/p-GaN (PNP-GaN) structured current spreading layer. The PNP-GaN current spreading layer can generate the energy band barrier in the valence band because of the modulated doping type, which is able to favor the current spreading into the aperture. By using the PNP-GaN current spreading layer, the thickness for the optically absorptive ITO current spreading layer can be reduced to decrease internal loss and then enhance the lasing power.

On the origin for the hole confinement into apertures for GaN-based VCSELs with buried dielectric insulators.

A better lateral current confinement is essentially important for GaN-based vertical-cavity-surface-emitting lasers (VCSELs) to achieve lasing condition. Therefore, a buried insulator aperture is adopted. However, according to our results, we find that the current cannot be effectively laterally confined if the insulator layer is not properly selected, and this is because of the unique feature for GaN-based VCSELs grown on insulating substrates with both p-electrode and n-electrode on the same side.

[Spatial pattern and evolutionary trend of sustainable development index of crop-livestock system: A case study in Shandong Province, China.].

The intensification and industrialization of agricultural production leads to more and more serious separation of crop and livestock, which causes serious contradiction between livestock excrement and environment, and major challenges for agricultural sustainable development. Here, we quantitatively investigated the spatial pattern and evolutionary trend of the sustainable development index (ESI) of the crop-livestock system using the emergy analysis and the input/output data in Shandong Province (1999-2015). The results showed that the sustainability of the crop-livestock system in Shandong Province decreased from 1999 to 2015 by 22.

Robust Electrodes with Maximized Spatial Catalysis for Vanadium Redox Flow Batteries.

Catalytic efficiency is a crucial index for electrodes in flow batteries, and tremendous efforts have been devoted to exploring catalysts with as many reaction zones as possible. Nevertheless, the space between the reaction sites, especially for interstitial space utilization, is usually ignored and challengeable to exploit owing to the balance between the catalytic efficiency and structural stability. Herein, a three-dimensional conducting network was constructed via a nitrogen-rich carbon film-bridged graphite felt framework (GF@N-C) to maximize its electrocatalytic effectiveness toward redox species.

Three-Dimensional Carbon Nanotubes Forest/Carbon Cloth as an Efficient Electrode for Lithium-Polysulfide Batteries.

The development of a three-dimensionally flexible, large-surface area, high-conductivity electrode is important to improve the low conductivity and utilization of active materials and restrict the shuttle of long-chain polysulfides in Li-polysulfide batteries. Herein, we constructed an integrated three-dimensional carbon nanotube forest/carbon cloth electrode with heteroatom doping and high electrical conductivity. The as-constructed electrode provides strong trapping on the polysulfide species and fast charge transfer.