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Land use contradictions between economic development, food security and ecological protection are becoming more and more prominent with the rapid development of urbanization and industrialization in China. Land use engineering is an important support to alleviate land use contradictions. Chinese policy-makers have recognized the important role of land-use engineering on land use contradictions. The central government budget invested in land use engineering increases gradually. Standardization is of great significance to promote land use engineering practice. However, standardization level of land use engineering is still very low. The number of standards is rare. There are only 26 standards related to land use engineering. It is far from the needs of land-use engineering practices. Land use engineering standard system, the blueprint for constructing and revising standards, has not yet been built. For this reason, land use engineering and its standard system connotation were initially expounded in this paper according to specific characteristics of land use engineering and standard system. Then, questionnaires and semi-structured interviews were employed to collect the current situation and the demand of the land use engineering standard, and the suggestion of standard system. Beijing, Guangzhou, Wuhan, Xining, Wuxi, Harbin, Sichuan were selected to implement the investigation. Numerous proposals on standard system and current standards were collected from different land experts and front-line land workers. The characteristics of the current situation and the demand of the land use engineering standard were analyzed for the construction of the standard system. Based on the basic principles for building land use engineering standard system and the work flow drawn out from a large number of land use engineering practices in different regions, Systems Engineering proposed by Hall was applied to put forward preliminary framework of land use engineering standard system from 3 dimensions, including specialized categories (comprehensive renovation, land development, land consolidation, land reclamation and land protection), specialized sequences (integration, investigation, appraisal, plan, construction, engineering and technology, materials and equipment, and management) and standard levels (basis standards, common standards, specialized standards). Specialized categories are divided by land use target and objects. Comprehensive renovation is systems engineering containing the remediation of paddy, water ditch, road, forest and village; land development changes the structures of land function bodies; land consolidation adjusts the structures of land function bodies; land reclamation recovers land function bodies; and land protection protects land function bodies. Specialized sequences are the independent technology processes or technical methods that are significantly different from other professional activities, which contain 5 first-stage classifications and 35 second-stage classifications. Standard levels are distinguished by the scope of application. Generally speaking, the number of basis standards is the least and specialized standards are the most. The hierarchical structure of the standard reflects the inner link between the standards. The upper standards limit the lower standards. Land use engineering standard system is different from the existing land resources standard system developed by China's Ministry of Land and Resources in objects, purposes and methods. Land use engineering standard system includes both existing standards and demand standards. In this paper, land use engineering standard system table including 49 demand standards is constructed and it may provide reference to make the long-term plan or annual plan for land use engineering standards. The established standard system is significant to promote standardization of land use engineering. [ABSTRACT FROM AUTHOR]

Background:Alpine and arctic ecosystems at high latitudes have been shown to be particularly vulnerable to climate change, but little has been reported about plant community responses from lower latitudes, such as the vast Qinghai–Tibetan Plateau. Aim:To examine how alpine fen plant community species richness, diversity, cover, above- and below-ground biomass, and how the abundance of two sedges, the dominantKobresia tibeticaand the subordinateCarex moorcroftii,respond to experimental warming. Methods:We used open-top chambers of two heights, with identical open-top area, to simulate two levels of experimental warming at 4700 m on the Qinghai–Tibetan Plateau. Results:Five years of experimental warming reduced species richness and diversity, primarily due to a decrease in the diversity of graminoids. Above-ground biomass, vegetation height and cover increased at both levels of warming. Below-ground biomass increased at a depth of 5–20 cm, but not at 0–5 cm, indicating an allocation of resource to plant roots in deeper soils. Conclusion:The different responses to warming between the two graminoids in the study suggest that further studies on species-specific responses are needed to understand the regional differences observed in response to long-term warming. Our study also documented a decline in species richness and diversity in the control plots during the five-year experimental period which, together with results from other studies in this region, suggests that the alpine fens are already changing in response to the on-going climate warming in this area. [ABSTRACT FROM AUTHOR]

Abstract: To investigate the mechanisms of the improvement on separation efficiency of photogenerated carriers, a Fe2O3/SrTiO3 heterojunction semiconductor with an improved separation efficiency was successfully prepared. The heterojunction semiconductor was characterized with X-ray diffraction (XRD), UV–vis absorption spectrum, scanning electron microscope (SEM) and surface photovoltage (SPV) spectroscopy. The energy band diagrams of Fe2O3 and SrTiO3 were determined with X-ray photoelectron spectroscopy (XPS), based on which the conduction band offset (CBO) between Fe2O3 and SrTiO3 was quantified to be 1.26 ± 0.03 eV. The recombination of photogenerated carriers was investigated with photoluminescence (PL) spectrum, which indicates that the formation of Fe2O3/SrTiO3 decreases the recombination. Thus the improved separation efficiency is mainly due to the energy difference between the conduction band edges of Fe2O3 and SrTiO3, and the decreased electron-hole recombination for Fe2O3/SrTiO3. [Copyright &y& Elsevier]

The scale issue is of central concern in hydrological processes to understand the potential upscaling or downscaling methodologies, and to develop models for scaling the dominant processes at different scales and in different environments. In this study, a typical permafrost watershed in the Qinghai-Tibet Plateau was selected. Its hydrological processes were monitored for 4 years from 2004 to 2008, measuring the effects of freezing and thawing depth of active soil layers on runoff processes. To identify the nature and cause of variation in the runoff response in different size catchments, catchments ranging from 1·07 to 112 km2 were identified in the watershed. The results indicated that the variation of runoff coefficients showed a 'V' shape with increasing catchment size during the spring and autumn seasons, when the active soil was subjected to thawing or freezing processes. A two-stage method was proposed to create runoff scaling models to indicate the effects of scale on runoff processes. In summer, the scaling transition model followed an exponential function for mean daily discharge, whereas the scaling model for flood flow exhibited a linear function. In autumn, the runoff process transition across multiple scales followed an exponential function with air temperature as the driving factor. These scaling models demonstrate relatively high simulation efficiency and precision, and provide a practical way for upscaling or downscaling runoff processes in a medium-size permafrost watershed. For permafrost catchments of this scale, the results show that the synergistic effect of scale and vegetation cover is an important driving factor in the runoff response. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Gd2O3:Sm3+ and Gd2O3:Sm3+,Bi3+ powders were prepared by a combustion method. Their structures were determined using X-ray diffraction. UV–visible absorption and photoluminescence spectra were investigated for Gd2O3:Sm3+ and Gd2O3:Sm3+,Bi3+ at different annealing temperatures and different doping concentrations. The emission spectra of all samples presented the characteristic emission narrow lines arising from the 4G5/2→6H J transitions (J=5/2, 7/2, and 9/2) of Sm3+ ions upon excitation with UV irradiation. The emission intensity of Sm3+ ions was largely enhanced with introducing Bi3+ ions into Gd2O3:Sm3+ and the maximum occurred at a Bi3+ concentration of 0.5mol%. The relevant mechanisms were discussed with the sensitization theory by Dexter and the aggregation behavior of Bi3+ ions. [Copyright &y& Elsevier]

The exploration of high-efficiency bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) has long been challenging. The rational design of a catalyst by constructing heterostructures and a doping element are possibly expected to achieve it. Herein, the utilization of flower-like Fe/C-doped-MoS2/Ni3S2-450 spherical structural materials for electrocatalytic HER and OER is introduced in this study. The carboxyferrocene-incorporated molybdenum sulfide/nickel sulfide (MoySx/NiS) nanostructures were prepared by solvothermal method. After annealing, the iron and carbon elements derived from ferrocenecarboxylic acid enhanced the electrical transport performance and provided rich electronic sites for HER and OER in alkaline media. Specifically, the optimized flower-like Fe/C-doped-MoS2/Ni3S2-450 exhibited efficient bifunctional performance in alkaline electrolyte, with low overpotentials of 188 and 270 mV required to deliver a current density of 10 mA cm−2 for HER and OER, respectively. This work provides valuable insights for the rational design of energy storage and conversion materials by the incorporation of transition metal and carbon elements into metal sulfide structures utilizing metallocene. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2) has been universally demonstrated to be an effective electrocatalytic catalyst for hydrogen evolution reaction (HER). However, the low conductivity, few active sites and poor stability of MoS2-based electrocatalysts hinder its hydrogen evolution performance in a wide pH range. The introduction of other metal phases and carbon materials can create rich interfaces and defects to enhance the activity and stability of the catalyst. Herein, a new defect-rich heterogeneous ternary nanocomposite consisted of MoS2, NiS and reduced graphene oxide (rGO) are synthesized using ultrathin αNi(OH)2 nanowires as the nickel source. The MoS2/rGO/NiS-5 of optimal formulation in 0.5 M H2SO4, 1.0 M KOH and 1.0 M PBS only requires 152, 169 and 209 mV of overpotential to achieve a current density of 10 mA cm−2 (denoted as η10), respectively. The excellent HER performance of the MoS2/rGO/NiS-5 electrocatalyst can be ascribed to the synergistic effect of abundant heterogeneous interfaces in MoS2/rGO/NiS, expanded interlayer spacings, and the addition of high conductivity graphene oxide. The method reported here can provide a new idea for catalyst with Ni-Mo heterojunction, pH-universal and inexpensive hydrogen evolution reaction electrocatalyst. [ABSTRACT FROM AUTHOR]

A water‐soluble fluorescent copolymer poly(acrylamide‐acrylic acid‐styrene pyridinium) (PAAS) for detecting polymer concentration in real time was synthesized via micellar free‐radical polymerization by acrylamide, acrylic acid, and styryl‐pyridinium salt derivative (SP‐4). The special Donor‐π‐Acceptor unit and ionic structure of SP‐4 endued the copolymer with excellent fluorescent properties and remarkable water solubility. The fluorescent copolymer was fully characterized by Fourier transform infrared, 1H nuclear magnetic resonance, thermogravimetry, Ubbelohde viscosity, ultraviolet–visible spectroscopy, and fluorescence measurements. Furthermore, the fluorescence intensity and the concentration of PAAS were verified to have ideal linear relationship with a correlation coefficient up to 0.9993, indicating that the copolymer's concentration can be easily measured by detecting its fluorescence intensity. Most importantly, the introduction of water‐soluble fluorescent monomer SP‐4 endowed the PAAS with good fluorescent stability in a wide range of temperature, pH, and brine concentrations. This study demonstrated that the fluorescent copolymer PAAS exhibits great potential application in detecting polymer concentration in various environments. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47062. [ABSTRACT FROM AUTHOR]

The anatase nanocrystalline TiO2 samples were synthesized by a sol-gel method with a thermal treatment under air and oxygen atmospheres at 500 °C and investigated by x-ray powder diffraction, ultraviolet-visible diffuse reflectance spectra (UV-vis DRSs), Raman spectra, and photoluminescence (PL) spectra, respectively. Compared to the sample calcined in air, there were slight differences in the lattice parameter and Raman line shape for the sample calcined in oxygen. UV-vis DRSs exhibited a visible redshift of the absorption edge, which could be understood by Burstein–Moss effect. Different calcination atmospheres led the obvious variations of intensity, position, and linewidth in the PL spectra, which could be attributed to the surface oxygen defect changes. [ABSTRACT FROM AUTHOR]

Bimetallic metal-organic frameworks (BMOFs) have shown a superior oxygen evolution reaction (OER) performance, attributed to the synergistic effects of dual metal sites. However, the significant role of these dual-metal synergies in the OER is not yet fully understood. In this study, we employed density functional theory to systematically investigate the OER performance of NiAl- and NiFe-based BMOFs by examining all possible spin states of each intermediate across diverse external potentials and pH environments. We found that the spin state featuring a shallow hole trap state and Ni ions with a higher oxidation state serve as strong oxidizing agents, promoting the OER. An external potential-induced spin crossover was observed in each intermediate, resulting in significant changes in the overall reaction and activation energies due to altered energy levels. Combining the constant potential method and the electrochemical nudged elastic band method, we mapped the minimum free energy barriers of the OER under varied external potential and pH by considering the spin crossover effect for both NiAl and NiFe BMOFs. The results showed that NiFe exhibits better OER thermodynamics and kinetics, which is in good agreement with experimentally measured OER polarization curves and Tafel plots. Moreover, we found that the improved OER kinetics of NiFe not only is attributed to lower barriers but also is a result of improved electrical conductivity arising from the synergistic effects of Ni-Fe dual-metal sites. Specifically, replacing the second metal Al with Fe leads to two significant outcomes: a reduction in both the band gap and the effective hole mass compared to NiAl, and the initiation of super- and double-exchange interactions within the Ni-F-Fe chain, thereby enhancing electron transfer and hopping and leading to the improved OER kinetics., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Development of a low cost, high activity, and stable nonprecious metal bifunctional catalyst for electrocatalytic water cracking is a hot topic and big challenge. In this paper, we prepared a nitrogen-doped carbon nanotube (NCNT)-enhanced three-dimensional self-supported electrocatalyst with CoP and Co 2 P coexistence by a two-step strategy of high-temperature carbonization and low-temperature phosphorylation. Furthermore, the induced three-dimensional carbon network skeleton facilitates rapid charge transfer. In addition, the active sites of the carbon foam (CF) are greatly increased by the construction of hollow structures. As a bifunctional electrocatalyst, CoP/Co 2 P/NCNT@CF exhibited excellent catalytic activity for both hydrogen evolution reaction and oxygen evolution reaction in alkaline media, requiring low overpotentials of 133 and 289 mV to obtain a current density of 10 mA cm -2 , respectively. Additionally, the synthesized catalysts also exhibit good long-term stability, maintaining high catalytic activity after 20 h of continuous operation. We also confirmed the main driving force to improve the electron transfer between the heterostructures of Co and P by XPS spectra. The excellent electrocatalytic performance can be attributed to the close synergy between the highly active CoP/Co 2 P/NCNT and CF. This study provides a new strategy for the design of highly active bifunctional self-supporting electrocatalysts., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Ternary composites have demonstrated better capability than binary composites in enhancing the mechanical properties of the modified epoxy resins and are, therefore, currently under intensive investigation. Herein, we report a novel ternary nanocomposite prepared by filling a binary BPF (bisphenol F epoxy resin)/SCPs (sugarcane-based carbon powders) matrix with C-coated inorganic fullerene-like tungsten disulfide (IF-WS 2 @C) nanoparticles, and the analysis of its interface synergetic effect using XPS/FTIR. This activated nano-carbon core-shell structure filler is considered an ideal nanofiller and shows the excellent mechanical performance of the ternary composites. XRD, IR, XPS, SEM, and TEM characterizations were applied in investigating this nanocomposite. The improvement of the thermal and mechanical properties demonstrated the enhancement effects of this nanofiller. The results show that the great improvement of the bending modulus of 39.4% increased with the addition of 0.5 wt% IF-WS 2 @C nanoparticles, while 34.1% enhancement of bending strength was obtained with the addition of 0.2 wt% IF-WS 2 @C nanoparticles. The hardness and thermal conductivity were also boosted up to 5.2% and 33.1% with 0.5 wt% addition, respectively. The incorporation of a chemically activated coating may provide a novel means for improving graphite crystallization, which could somehow expand the potential application of IF-WS 2 @C nanoparticles., Competing Interests: The authors declare no conflicts of interest., (This journal is © The Royal Society of Chemistry.)

Objective: To measure setup error of head and neck neoplasm in radiotherapy and discuss over effects of error on physical dose acting on target region and organs at risk of nasopharynx cancer (NPC) patients treated with intensity modulated radiation therapy (IMRT)., Methods: A total of 152 patients who developed head and neck neoplasm and received IMRT were randomly selected. Through comparing digital portal image and digital reconstruction image, we measured setup error, calculated expanding margin from clinical target volume (CTV) to planning target volume (PTV) and analyzed whether there was rules between setup error and treatment time. Additionally, 20 cases of NPC were selected. Three-dimensional error was simulated in planning system. Dose distribution was recalculated and a series of dose parameters of target volume and OAR were analyzed., Results: Setup error in left-right, head-feet and ventral-dorsal direction was (-0.62±1.46) mm, (-0.41±1.54) mm and (-0.31±1.67) mm respectively. Regarding limit value, the maximum and minimum value in left-right direction, head-feet direction and ventral-dorsal direction was 2.70 mm and -6.00 mm; 3.00 mm and -5.00 mm, 5.00 mm and -7.50 mm. Expanding margin from CTV to PTV was 2.26 mm, 1.88 mm and 1.97 mm in left-right direction, head-feet direction and ventral-dorsal direction., Conclusion: During IMRT, only when setup error is controlled below 3 mm can sharply reduce the damage caused by radiation to normal tissue; therefore, quality security and control of electronic portal imaging device need (EPID) to be improved.