Bimetallic Single‑Atom Catalysts for Water Splitting

Green hydrogen from water splitting has emerged as a critical energy vector with the potential to spearhead the global transition to a fossil fuel-independent society.The field of catalysis has been revolutionized by single-atom catalysts(SACs),which exhibit unique and intricate interactions between atomically dispersed metal atoms and their supports.Recently,bimetallic SACs(bimSACs)have garnered significant attention for leveraging the synergistic functions of two metal ions coordinated on appropriately designed supports.BimSACs offer an avenue for rich metal–metal and metal–support cooperativity,potentially addressing current limitations of SACs in effectively furnishing transformations which involve synchronous proton–electron exchanges,substrate activation with reversible redox cycles,simultaneous multi-electron transfer,regulation of spin states,tuning of electronic properties,and cyclic transition states with low activation energies.This review aims to encapsulate the growing advancements in bimSACs,with an emphasis on their pivotal role in hydrogen generation via water splitting.We subsequently delve into advanced experimental methodologies for the elaborate characterization of SACs,elucidate their electronic properties,and discuss their local coordination environment.Overall,we present comprehensive discussion on the deployment of bimSACs in both hydrogen evolution reaction and oxygen evolution reaction,the two half-reactions of the water electrolysis process.

ACC and MACC Biosynthesis and Ethylene Production in Water-Stressed Spring Wheat

Changes of ACC and MACC levels, ACC synthase activity as well as ethylene production in the leaves of two spring wheat (Triticum aestivum L.) cultivars 8139 (with relatively low drought-resistance) and 504 (with relatively high drought-resistance) during water stress were determined. The levels of ACC and MACC in both cultivars decreased in the first 24 It of water stress and increased in the second 24 It while the activities of ACC synthase increased continuously throughout the entire period of treatment (48 h), As water stress progressed, ethylene production decreased continuously in cv. 8139 but remarkably increased earlier and decreased later in the cv. 504. Moreover, the decrease in RWC of stressed leaves was greater and the changes in ACC and MACC levels as well as ACC synthase activity were higher in the drought-sensitive cv. 8139 than in the drought-resistant cv, 504 during water stress. The levels of ACC and MACC, activities of ACC synthase and productions of ethylene in the stressed leaves in two cultivars were significantly altered by the application of MGBG (an inhibitor of SAMDC) and AOA (an inhibitor of ACC synthase) where their effects on these items were almost opposite. They were increased by the former inhibitor but reduced by the latter. All of these results suggested that the level of ethylene production in plants did not depend on the level of ACC during water stress. The increase in the level of ethylene in the drought-resistant cultivar during the earlier period of water stress might be a phenomenon of adaptation to water stress and be correlated with the development of the drought-tolerance in plants and playing role in the transduction of stress signal. The role of MACC, however, was primarily in the regulation of ethylene production under water stress.

A Simplified Model with Soil Water Limitation on Spring Wheat Growth

The authors constructed a simplified model of spring wheat (Triticum aestivum L.) carbon assimilation and dry matter accumulation (DMA) process which consisted of two independent variables, day length (L) and total daily radiation (TDR). Leaf water potential (Ψ) was incorporated into the simplified growth model based on the assumption that both light use efficiency (α) and CO 2 conductance of assimilation (g c) were depressed by water limitation. Finally,Ψ was estimated from a regression equation in which the independent variables were relative soil water content in the upper 80 cm (θ R,80 ), ambient temperature (T a), vapor pressure deficit (VPD), the cumulative leaf water potential below thresholds of -1.5 MPa (Ψ c,1.5 ). Some applications in research program of field experiment of atmosphere_land surface processes in Heihe River region were tested. The simulated data agreed well with the data observed at Linze oasis in 1989 for various levels of water supply and at Zhangye oasis in 1992 in the field. The analysis and simulation using the model demonstrated that the simplified growth model could describe very well the DMA process of spring wheat with and without water limitation in the region of HEIFE (Heihe field experiment).

Effects of Super Absorbent Polymers on Yield and Water-saving and Drought-escaping Mechanism in Spring Maize

The effects of super absorbent polymers （SAP） on yield as well as water-saving and drought-escaping mechanism in spring maize in the seasonal drought region were studied. As shown by the results, during the seasonal drought in southern China, SAP treatment promoted the soil moisture, improved the capability of absorption and transportation of roots, promoted physiological and biochemical functions, increased the chlorophyll content, photosynthetic rate and intercellular CO2 concentration, and reduced the stomatal conductance and transplre.tion rate. As a result, the economic characters of spring maize were improved, and the yield was increased.

Response of Growth and Water Use Efficiency of Spring Wheat to Whole Season CO_2 Enrichment and Drought

Whole_growing season pot experiments were conducted to examine the response of growth and water use efficiency ( WUE ) of spring wheat ( Triticum aestivum L. cv. Gaoyuan 602) to CO 2 enrichment. Wheat plants were grown in open_top chambers (OTCs) subject to two concentrations of CO 2 ()(350 and 700 μL/L, hereafter 'ambient' and 'elevated' respectively) and three soil water levels (80%, 60% and 40% field water capacity ( FWC ), hereafter 'high soil moisture', 'medium soil moisture' and 'low soil moisture' respectively). Elevated CO 2 greatly increased leaf net photosynthesis ( Pn ) at all three soil water levels. The Pn of plants growing under elevated was 22% lower than that of plants growing at ambient when measured with the same (700 μL/L). Plant growth was enhanced by elevated throughout the growing season, with an increase of 14.8% in shoot dry weight at harvest under high soil moisture, and leaf area was increased by about 20% at all three soil water levels. Elevated in combination with high soil moisture increased the ratio of plant shoot dry weight to height by 15.7%, while this ratio was decreased by over 50% when plants were subject to drought. Elevated also increased the water use efficiency of wheat, mainly due to decreases in transpiration and cumulative consumption of water, and an increase in shoot dry weight, with the biggest value of 30% occurring at high soil water moisture level. Compared to high soil moisture, drought decreased shoot dry weight by 72% under ambient , and by 76% under elevated . Similarly, drought also reduced WUE by 19% under ambient , and 23% under elevated . Our results indicate that: (1) elevated can increase the photosynthetic rates, growth and WUE of wheat plants; (2) long_term exposure to high may result in lower photosynthetic capacity; (3) high stimulates plants lateral growth more than vertical growth; (4) the effects of CO 2 enrichment on plants depend on soil water status, with plants benefiting more from CO 2 enrichment if sufficient water is supplied; and (5) drought may cause relatively more reduction in plant growth and WUE under future elevated conditions.

Experimental Study on the Utilization of Shallow Groundwater for Spring Wheat

[Objective]The paper aimed to study effect of shallow groundwater at different depths on crop water requirement and crop evaporation in spring wheat field.[Method]Five treatments of shallow groundwater table at different depth were designed to do evaporation experiment for spring wheat in 2008-2009.[Result]The groundwater at different depths had great impact on crop growth and field evaporation;its supply accounted for 0-52% of actual evapotranspiration.Atmospheric evaporation and crop rooting depth were the major factors to affect the uptake of groundwater at shallow table,and the supply of deep groundwater was controlled by groundwater table.[Conclusion]The study reveled the pattern of evapotranspiration of spring wheat and evaporation of shallow groundwater at different depth,in order to supply basis for the rational and effective utilization of shallow groundwater as well as optimization of the irrigation scheduling for spring wheat.

基于SpringBoot框架的智慧校园管理系统设计与实现

随着国家《智慧校园总体框架》的提出,各职业院校纷纷启动了智慧校园的建设,因学校发展实际情况、重视程度、资金投入等不同,智慧校园建设的步伐也不一致。文章分析了智慧校园管理系统需求,提出基于Spring Boot框架,整合MyBatis数据持久化框架,数据库选择高性能的MySQL,内存数据库采用Redis缓存技术,采用前后端分离模式设计,前端采用Vue.js、Element-UI、Axios来实现前后端数据交互的系统设计方案和实现过程,为智慧校园的建设提供一种可行的方案参考。

基于Spring Boot的产教联合体信息平台设计

该文设计基于B/S架构的联合体信息平台,利用Spring Boot、MyBatis Plus、Vue等优秀框架实现高效的开发,集成Spring Security和JWT令牌机制,完成认证和权限控制。同时整合Redis缓存,将热点资源缓存至内存中,以实现快速查询操作,从而减轻MySQL数据库的负载压力。该系统稳定、兼容性强,能使联合体成员沟通更方便、信息的发布和维护的效率更高,实现人才共育共享。

Root carbon consumption and grain yield of spring wheat in response to phosphorus supply under two water regimes

In semiarid areas, cereal crops often alocate more biomass to root at the expense of aboveground yield. A pot experiment was conducted to investigate carbon consumption of roots and its impact on grain yield of spring wheat （Triticum aestivum L.） as affected by water and phosphorus （P） supply. A factorial design was used with six treatments namely two water regimes （at 80–75% and 50–45% ifeld capacity （FC）） and three P supply rates （P1=0, P2=44 and P3=109 μg P g–1 soil）. At shooting and lfowering stages, root respiration and carbon consumption increased with the elevate of P supply rates, regardless of water conditions, which achieved the minimum and maximum at P1 under 50–45% FC and P3 under 80–75% FC, respectively. However, total aboveground biomass and grain yield were higher at P2 under 80–75% FC; and decreased with high P application （P3）. The results indicated that rational or low P supply （80–75% of ifeld water capacity and 44 mg P kg–1 soil） should be recommended to improve grain yield by decreasing root carbon consumption in semiarid areas.

基于Spring Boot+Vue框架的羊场综合 管理系统软件的设计与应用

本研究旨在辅助羊场生产数据规范化管理及良种繁育智能科学化应用,采用MySQL数据库及Java、R编程语言,基于Spring Boot+Vue框架设计了一套羊场综合管理系统软件。该系统优化了羊只信息管理、羊场配种方案,实现生产数据可视化,设置预警功能帮助羊场及时掌握羊只产羔时间与生产性能情况;系统设计羊只基本信息管理、生产信息、疫病信息、繁殖信息、药品管理、饲料管理、统计报表与预警、科学育种八个模块。其中,在科学育种管理子模块中,根据羊场育种需求,构建了三种育种值计算模型(BLUP模型、GLMM模型、平均表现型模型),结合种公母羊实际表现,实现种公母羊的等级排序并自动生成近交系数,得到科学合理的配种方案。本系统在陕北某集约化肉羊场、横山区某绒山羊养殖联合育种户、富平县某奶山羊养殖场进行为期半年的实际生产应用,通过跟踪核心群体,完善与优化系统各项功能,为羊场智慧化、数字化育种管理提供了数据平台,同时也为实现智慧羊场的发展增添了新版本1.0。

Water Requirements and Irrigation Scheduling of Spring Maize Using GIS and CropWat Model in Beijing-Tianjin-Hebei Region

Due to the over use of available water resources, it has become very important to define appropriate strategies for planning and management of irrigated farmland. In this paper, Beijing-Tianjin-Hebei (Jing-Jin-Ji) region was chosen as the case study area for its special political and economic status and its severe water problem. To achieve effective planning, the information about crop water requirements, irrigation withdrawals, soil types and climatic conditions were obtained in the study area. In the meantime, a GIS method was adopted, which extends the capabilities of the crop models to a regional level. The main objectives of the study are: 1) to estimate the spatial distribution of the evapotranspiration of spring maize; 2) to estimate climatic water deficit; 3) to estimate the yield reduction of spring maize under different rainfed and irrigated conditions. Based on the water deficit analysis, recommended supplemental irrigation schedule was developed using CropWat model. Compared to the rainfed control, the two or three times of supplemental water irrigated to spring maize at the right time reduced the loss of yield, under different scenarios.

Geochemical Constraints on the Origin and Evolution of Spring Waters in the Changdu-Lanping-Simao Basin, Southwestern China

Chemical and isotopic data were measured for 51 leached brine springs in the Changdu-Lanping-Simao Basin(CD-LP-SM),China.The predominance of Cl and Na,saturation indices of carbonate minerals,and Na/Cl and Ca/SO4 ratios of^1 suggest that halite,sulphate,and carbonate are the solute sources.Integration of geochemical,δ18 O,andδD values suggests that springs are mainly derived from meteoric water,ice-snow melt,and water-rock interactions.B concentrations range from 0.18 to 11.9 mg/L,withδ11 B values of-4.37‰to+32.39‰,indicating a terrestrial source.Theδ11 B-B relationships suggest B sources of crustal origin(marine carbonates with minor crust-derived volcanics);we did not identify a marine or deep mantle origin.Theδ11 B values of saline springs(+4.61‰to+32.39‰)exceed those of hot(-4.37‰to+4.53‰)and cold(-3.47‰to+14.84‰)springs;this has contributed to strong water-rock interactions and strong saturation of dissolved carbonates.Conversely,the global geothermalδ11 B-Cl/B relationship suggests mixing of marine and non-marine sources.Theδ11 B-Cl/B relationships of the CD-LP-SM are similar to those of the Tibet geothermal belt and the Nangqen Basin,indicating the same B origin.These differ from thermal waters controlled by magmatic fluids and seawater,suggesting that B in CD-LP-SM springs has a crustal origin.

Tillage and straw mulching impacts on grain yield and water use efficiency of spring maize in Northern Huang–Huai–Hai Valley

A two-year field experiment(2012–2013) was conducted to investigate the effects of two tillage methods and five maize straw mulching patterns on the yield, water consumption,and water use efficiency(WUE) of spring maize(Zea mays L.) in the northern Huang–Huai–Hai valley of China. Compared to rotary tillage, subsoil tillage resulted in decreases in water consumption by 6.3–7.8% and increases in maize yield by 644.5–673.9 kg ha-1, soil water content by 2.9–3.0%, and WUE by 12.7–15.2%. Chopped straw mulching led to higher yield,soil water content, and WUE as well as lower water consumption than prostrate whole straw mulching. Mulching with 50% chopped straw had the largest positive effects on maize yield, soil water content, and WUE among the five mulching treatments. Tillage had greater influence on maize yield than straw mulching, whereas straw mulching had greater influence on soil water content, water consumption, and WUE than tillage. These results suggest that 50% chopped straw mulching with subsoil tillage is beneficial in spring maize production aiming at high yield and high WUE in the Huang–Huai–Hai valley.

Assessing Crop Water Demand and Deficit for the Growth of Spring Highland Barley in Tibet, China

The aim of this study was to assess the crop water demand and deficit of spring highland barley and discuss suitable irrigation systems for different regions in Tibet, China. Long-term trends in reference crop evapotranspiration and crop water demand were analyzed in different regions, together with crop water demand and deficit of spring highland barley under different precipitation frequencies. Results showed that precipitation trends during growth stages did not benefit the growth of spring highland barley. The crop coefficient of spring highland barley in Tibet was 0.87 and crop water demand was 389.0 ram. In general, a water deficit was found in Tibet, because precipitation was lower than water consumption of spring highland barley. The most severe water deficit were in the jointing to heading stage and the heading to wax ripeness stage, which are the most important growth stages for spring highland barley; water deficit in these two stages would be harmful to the yield. Water deficit showed different characteristics in different regions. In conclusion, irrigation systems may be more successful if based on an analysis of water deficit within different growth stages and in different regions.

基于Vue.js与Spring Boot的教务管理系统设计

随着Web应用开发技术的不断发展,采用传统Web技术开发的教务管理系统越来越难满足实际需求,在此背景下,提出了一种同时基于Vue.js与Spring Boot的教务管理系统设计与实现方案。该系统采用Vue.js框架作为前端开发框架,实现了前台页面的交互和后台数据展示。同时,使用Spring Boot作为后端框架,提供了稳定的数据请求和数据存储功能。阐述了系统的架构设计、技术实现和功能需求设计等方面内容。该设计方案,使系统具有速度快、效率高、稳定性强等优点,带来良好的用户体验,同时能够满足教务管理的需要。采用该架构设计的系统同时也具有很好的可扩展性和可移植性,方便学校进行二次开发和部署。

Hydrogeochemical and isotopic characteristics of spring water in the Yarlung Zangbo River Basin, Qinghai-Tibet Plateau, Southwest China

The Yarlung Zangbo River Basin(YZRB)is situated in the southern part of the Tibetan Plateau and remains in a mostly natural state.To understand the chemical characteristics of spring water and its controlling factors in the YZRB,68 sets of spring water samples were analyzed using hydrochemical and isotopic techniques.The spring water was found to be slightly alkaline with total dissolved solids(TDS)below 1000 mg L−1.Major ions were Mg2+,Ca2+,SO42−,and HCO3−.The spring water types in this basin were determined to be HCO3-Ca·Mg and SO4·Cl-Ca·Mg.Ion exchange and dissolution of carbonate,gypsum,and silicate were identified as the prevalent hydrogeochemical processes contributing and defining spring water chemistry in this basin.Saturation indices(SI)of most major minerals studied in this region were below zero,indicating that these minerals remain under-saturated in the spring water in this area.Overall,the rank of different processes in terms of their contribution to the chemical composition of spring water in the YZRB was carbonate weathering>evaporate dissolution>silicate weathering>precipitation input.The content of 18O in spring water ranged from−22.22‰to−14.08‰with a mean of−18.15‰.Samples collected below and close to the local and global meteoric water lines indicated that spring water in this area is derived from meteoric water with chemistry affected by evaporation.

Hydrochemical and isotope characteristics of spring water discharging from Qiushe Loess Section in Lingtai, northwestern China and their implication to groundwater recharge

The loess plateau in northwestern China with an area of 640 000km^2, which has developed the loess deposits with a thickness up to 200m in typical areas, is regarded as a huge carbon stock like the karst area in southwestern China, and plays an important role in regional(even global) carbon cycle. But the spring discharging from loess is poorly known compared with karst spring so far. The objective of this study is to ascertain the characteristics and origin of spring at Qiushe Village, Lingtai County, Gansu Province by hydro-chemical and isotopic methods. The results show that the springs including LGQ, HMQ, YYQ and CZQ are the depression spring and belong to the same shallow aquifer with the well water JZJ. There are not distinct seasonal/diurnal-scale variations on the hydro-chemical characteristics of the spring water(LGQ, HMQ, YYQ, CZQ) and groundwater(JZJ). The hydro-chemical type of groundwater is Ca·Mg-HCO_3. The D and O isotope ratios indicate that the precipitation is the main recharge source of groundwater in study area. And the results of tritium(TU) and Cl concentration suggest that the recharge cycle of groundwater may be more than 60 yrs. Our study shows that the water cycle in loess plateau including rainfall, infiltration, recharge and discharge exerts a continuous impact on carbon stock in loess, which should be paid more attention to in future research on the quantitative reconstruction of paleoclimate.

Changing Spring Phenology Dates in the Three-Rivers Headwater Region of the Tibetan Plateau during 1960–2013

The variation of the vegetation growing season in the Three-Rivers Headwater Region of the Tibetan Plateau has recently become a controversial topic. One issue is that the estimated local trend in the start of the vegetation growing season(SOS)based on remote sensing data is easily affected by outliers because this data series is short. In this study, we determine that the spring minimum temperature is the most influential factor for SOS. The significant negative linear relationship between the two variables in the region is evaluated using Moderate Resolution Imaging Spectroradiometer–Normalized Difference Vegetation Index data for 2000–13. We then reconstruct the SOS time series based on the temperature data for 1960–2013.The regional mean SOS shows an advancing trend of 1.42 d(10 yr)during 1960–2013, with the SOS occurring on the 160th and 151st days in 1960 and 2013, respectively. The advancing trend enhances to 6.04 d(10 yr)during the past 14 years. The spatiotemporal variations of the reconstructed SOS data are similar to those deduced from remote sensing data during the past 14 years. The latter exhibit an even larger regional mean trend of SOS [7.98 d(10 yr)] during 2000–13. The Arctic Oscillation is found to have significantly influenced the changing SOS, especially for the eastern part of the region,during 2000–13.

Effects of deficit irrigation with saline water on spring wheat growth and yield in arid Northwest China

Field experiments were conducted in 2008 and 2009 to study the effects of deficit irrigation with saline water on spring wheat growth and yield in an arid region of Northwest China. Nine treatments included three salinity levels sl, s2 and s3 （0.65, 3.2, and 6.1 dS/m） in combination with three water levels wl, w2 and w3 （375, 300, and 225 mm）. In 2008, for most treatments, deficit irrigation showed adverse effects on wheat growth; meanwhile, the effect of saline irrigation was not apparent. In 2009, growth parameters of wl treatments were not always optimal under saline irrigation. At 3.2 and 6.1 dS/m in 2008, the highest yield was obtained by wl treatments, however, in 2009, the weight of 1,000 grains and wheat yield both followed the order w2 〉 wl 〉 w3. In this study, spring wheat was sensitive to water deficit, especially at the booting to grain-filling stages, but was not significantly affected by saline irrigation and the combination of the two factors. The results demonstrated that 300-mm irrigation water with a salinity of less than 3.2 dS/m is suitable for wheat fields in the study area.

The black water around the Changjiang (Yangtze) Estuary in the spring of 2003

The Changjiang （Yangtze） Estuary is located in the East China Sea shelf with shallow water. Affected by the tide mixing and the runoff of the Changjiang River and the Qiantang River the turbidity is very high. Generally, the water-leaving radiance is high in the turbid water because of the large particle scattering. Based on the in-situ data and ocean color remote sensing data of SeaWiFS, it was found that there was a black water region with the normalized water-leaving radiances less than 0.5 mW/（cm2-μm2-sr）. The optical principle of the occurrence of this black water was analyzed by the inherent optical properties and the ocean color components. The results show that black water is caused by the relative low values of the suspended particle matter concentration and the back scattering ratio. In the black water region, the percentage of the phytoplankton absorption was relatively high, and the large size of the phytoplankton caused the low value of the particle backscattering ratio.