Unveiling evapotranspiration patterns and energy balance in a subalpine forest of the Qinghai-Tibet Plateau:observations and analysis from an eddy covariance system

Evapotranspiration is an important parameter used to characterize the water cycle of ecosystems.To under-stand the properties of the evapotranspiration and energy balance of a subalpine forest in the southeastern Qinghai-Tibet Plateau,an open-path eddy covariance system was set up to monitor the forest from November 2020 to October 2021 in a core area of the Three Parallel Rivers in the Qing-hai-Tibet Plateau.The results show that the evapotranspira-tion peaked daily,the maximum occurring between 11:00 and 15:00.Environmental factors had significant effects on evapotranspiration,among them,net radiation the greatest(R^(2)=0.487),and relative humidity the least(R^(2)=0.001).The energy flux varied considerably in different seasons and sensible heat flux accounted for the main part of turbulent energy.The energy balance ratio in the dormant season was less than that in the growing season,and there is an energy imbalance at the site on an annual time scale.

Investigation of Nuclear Binding Energy and Charge Radius Based on Random Forest Algorithm

The random forest algorithm was applied to study the nuclear binding energy and charge radius.The regularized root-mean-square of error(RMSE)was proposed to avoid overfitting during the training of random forest.RMSE for nuclides with Z,N>7 is reduced to 0.816 MeV and 0.0200 fm compared with the six-term liquid drop model and a three-term nuclear charge radius formula,respectively.Specific interest is in the possible(sub)shells among the superheavy region,which is important for searching for new elements and the island of stability.The significance of shell features estimated by the so-called shapely additive explanation method suggests(Z,N)=(92,142)and(98,156)as possible subshells indicated by the binding energy.Because the present observed data is far from the N=184 shell,which is suggested by mean-field investigations,its shell effect is not predicted based on present training.The significance analysis of the nuclear charge radius suggests Z=92 and N=136 as possible subshells.The effect is verified by the shell-corrected nuclear charge radius model.

Seasonal Dynamics of Energy Return Through Litterfall of A Mixed Forest of Chinese Fir and T. odorum

Based on the measurement of monthly litterfall and their gross calor ic values, the seasonal dynamics of energy return through litterfall were determ ined in a pure and a mixed T. odorum (Tsoongiodendron odorum Chun) forests with Ch inese fir (Cunninghamia lanceolata (Lamb.) Hook.) in Sanming, Fujian Provinc e. Annual ene rgy return through litterfall was estimated as 12.648×10 6J·m -2 for the mixed fo rest, being 4 2% higher than that of the pure forest, and a large proportion of the energy return comprised leaf litter. The conversion efficiency of solar rad i ation energy into litterfall was 0 56% for mixed forest and 0 54% for pure for es t, respectively. The monthly energy flux in litterfall of Chinese fir showed a t hree-apex curve, peaked in March, August and December, respectively, which was s imilar to that in various fractions of leaf, twig, flower and fruit litter. The consistency in monthly patterns among different litter fractions of Chinese fir was attributed to their solid connections all the while. The monthly energy flux in litterfall of T. odorum culminated in January, May and August, the same was true for its leaf and twig litter. However, energy flux in flower litter only oc curred during March to May and that in fruit litter appeared in January and Marc h. The monthly dynamics of energy flux through litterfall of the two forests wer e both determined by their respective litterfall pattern of Chinese fir. Seasona l energy flux in litterfall for both mixed and pure forests followed the sequenc e of spring>winter>summer>autumn, but fluctuations in the former were less disti nct than those in the latter.

Ecosystem Productivity and Energy Flow of Three-Hardwood Forest

The main characteristics of energy environment, energy products, primary productivity and basic process ofenergy flow for three-hardwood forest(Juglans mandshurica, Fraxinus mandshurica, and Phellodendron amurense) werestudied. The research was mainly hased on the thcory and method of community energetics, dealing with fixed position,quantitative test and expcrimental analysis. The time-space dynamics of sun-radiation in three-hardwood forest were measured and the energy compartment model was set up. his rescarch work provided a scientitic basis for the exploitation, utilization and management of three-hardtwood forest.

Energy of forest systems in the Three Gorge Reservoir area

The energies of three forest ecosystems in the Three Gorge Reservoir area were analyzed. The results showed that the existing energies were 151 2438, 139 2014 and 175 1659 (×10 10 J/hm 2), the annual net fixed energies were 38 8924, 31 2214 and 46 8231 (×10 10 J/hm 2), and the utilization efficiency of light energies were 1 16, 0 99 and 1 40 for the Quercus acutissima forest(Q.A.), the Pinus massoniana forest (P.M.), and the Queresus acutissima and Pinus massoniana mixed forest (Q.P.), respectively. In the Three Gorge Reservoir Area, the energy efficiency of Quercus acutissima and Pinus massoniana mixed forest is the best.

Estimating potential harvestable biomass for bioenergy from sustainably managed private native forests in Southeast Queensland, Australia

Background： Australia＇s energy future is at the crossroads and the role of renewable sources is in focus. Biomass from sustainably managed forests provide a significant opportunity for electricity and heat generation and production of liquid fuels. Australia has extensive native forests of which a significant proportion are on private land. However, there is limited knowledge on the potential capacity of this resource to contribute to the expansion of a biomass for bioenergy industry. In addition, there are concerns on how to reconcile biomass harvesting with environmental protection. Methods： We used regional ecosystem vegetation mapping for Queensland to stratify harvestable forests within the 1.8 m hectares of private native forests present in the Southeast Queensland bioregion in 2014. We used a dataset of 52,620 individual tree measurements from 541 forest inventory plots collected over the last 10 years. Tree biomass was estimated using current biomass allometric equations for Australia. Biomass potentially available from selective sawlog harvesting and silvicultural treatment across the bioregion was calculated and mapped. Results： Current sawlog harvesting extracts 41.4% of the standing tree biomass and a biomass for bioenergy harvest would retain on average 36% of felled tree biomass on site for the protection of environmental and fauna habitat values. The estimated area extent of harvestable private native forests in the bioregion in 2013 was 888,000 ha and estimated available biomass for bioenergy in living trees was 13.6 million tonnes （t）. The spotted gum （Corymbio citriodora subsp, variegata） forests were the most extensive, covering an area of 379,823 ha and with a biomass for bioenergy yield of 14.2 t-ha-1 （with approximately 11.2 t.ha-1 of the biomass harvested from silvicultural thinning and 3 t.ha-1 recovered from sawlog harvest residual）. Conclusions： Silvicultural treatment of private native forests in the Southeast Queensland bioregion, has the capacity to supply a large quantity of biomass for bioenergy. The availability of a biomass for bioenergy market, and integration of sawlog harvesting and silvicultural treatment operations, could provide land owners with additional commercial incentive to improve the management of private native forests. This could potentially promote restoration of degraded forests, ecological sustainability and continued provision of wood products.

Mangrove forests as a nature-based solution for coastal flood protection:Biophysical and ecological considerations

Nature-based coastal protection is increasingly recognised as a potentially sustainable and cost-effective solution to reduce coastal flood risk.It uses coastal ecosystems such as mangrove forests to create resilient designs for coastal flood protection.However,to use mangroves effectively as a nature-based measure for flood risk reduction,we must understand the biophysical processes that govern risk reduction capacity through mangrove ecosystem size and structure.In this perspective,we evaluate the current state of knowledge on local physical drivers and ecological processes that determine mangrove functioning as part of a nature-based flood defence.We show that the forest properties that comprise coastal flood protection are well-known,but models cannot yet pinpoint how spatial heterogeneity of the forest structure affects the capacity for wave or surge attenuation.Overall,there is relatively good understanding of the ecological processes that drive forest structure and size,but there is a lack of knowledge on how daily bed-level dynamics link to long-term biogeomorphic forest dynamics,and on the role of combined stressors influencing forest retreat.Integrating simulation models of forest structure under changing physical(e.g.due to sea-level change)and ecological drivers with hydrodynamic attenuation models will allow for better projections of long-term natural coastal protection.

Academia-Forest Machine Industry Collaboration in Sustainable Energy Production： A Literature Review

In this literature review, the Academia, a forest machine industry collaboration is considered, which has been a cornerstone of innovation for sustainable energy production in the Finnish forest sector. The approach has been a significant means of achieving economic growth to Joensuu, an East Finnish university town of almost 73,500 inhabitants that is located near the Finland-Russia border and approximately 430 kilometers from Finland＇s capital city, Helsinki. Over 70% of the world＇s high-tech forest harvesters are made in Eastern Finland for energy wood harvesting of renewable forests. Annually, over 1,000 harvesters are manufactured in John Deere＇s machine factory in Joensuu. The amount comprises one third of the total amount of known annual harvester manufacture. A harvester costs from 300,000 euros to 400,000 euros. Therefore, the collaborators, regard the activities as significant green business turnover to the region and Joensuu is now a globally recognized brand among wood procurement professionals. Additionally, the Joensuu region is the Finnish center of the Nordic forest machine cluster and education. In this paper, the author will present two examples of fruitful development projects for energy wood harvesting in sustainable energy production.

能源资源开发区域大气CO_(2)时空变化及影响因素分析

分析能源资源开发区域大气碳浓度的时空变化和影响因素,对于探索“碳达峰”“碳中和”背景下能源资源开发高质量发展路径至关重要。新疆维吾尔自治区是我国重要的能源和战略资源基地,本文面向新疆维吾尔自治区的能源资源开发现状,采集并预处理了2015—2021年轨道碳观测卫星-2(Orbiting Carbon Observatory-2,OCO-2)二氧化碳L3数据产品,分析研究区大气碳浓度的时间变化趋势和空间分布格局,构建深度森林回归模型,并分析各影响因素对碳浓度时空变化的驱动作用。结果表明:(1)新疆维吾尔自治区、准噶尔盆地、吐哈盆地和塔里木盆地XCO_(2)浓度在2015—2021年均呈周期性上升趋势,增长率呈“先减后增”,且季节变化趋势呈现明显的“春季高冬季低”;(2)在春、秋和冬季,新疆XCO_(2)浓度空间格局呈现“北高南低”的趋势,在盆地区域及能源资源开发区域出现XCO_(2)高浓度积聚现象,夏季则呈现“北低南高”趋势;(3)地形起伏、风场流速、NDVI、地表温度、降水量、10 mV风、10 mU风和能源开发强度对区域XCO_(2)浓度时空分布有显著影响,各因素呈现明显的空间异质性和显著差异。研究结果有助于理解能源资源开采区域的大气碳浓度时空演变机制,在国家碳减排目标的实现、指导碳中和策略、追踪碳减排效果等方面具有深远意义。

现代林产化学加工技术的现状与发展趋势

生物质资源来源广泛,具有可再生性、结构多样性和碳中性等特点。目前,以生物质为原料的林产化工已成为继煤和石油化工之后最重要的化工产业之一。在对中国的林产化学工业发展历史概览的基础上,梳理总结了现代林产化学工业的发展,创新地提出了林产化学加工工程学科发展的能源化、材料化、食药化、饲料化、肥料化和基料化6个方向。其中,能源化中的生物质气/液/固体燃料的有效开发是实现碳达峰和碳中和的重要途径之一,而我国林产化工的传统研究领域制浆造纸、木本油脂、松脂化学等则从材料化找到新的突破和发展,相比前两者,食药化、饲料化、肥料化和基料化还有很大的发展空间。林产化学工业已迈入质量和效益持续提升发展新阶段,今后将在生物质资源高值化利用、全质利用技术创新、精深加工与应用、绿色低碳与生物技术融合、生物基材料与化学品创新应用,以及多学科交叉融合等方面实现突破,推动产业转型升级,构建绿色低碳循环发展新模式。

煤矿智能化排水系统的应用研究

排水系统是煤矿井下的关键系统之一,对于排出煤矿井下涌水,保障煤矿安全生产具有重要意义。针对现有矿井排水系统智能化水平较低、系统耗电量较大等问题,提出一种矿井智能化排水系统,系统以可编程控制器PLC为核心,通过模糊控制算法分析井下水仓的液位和涌水变化率,得出排水系统的最佳运行方案,并将该模型结构输入到PLC中,结合排水主管路的流量、水泵压力等数据,达到水泵房智能运行与避峰填谷的目的,并通过随机森林算法解析水泵的振动信号,分析水泵的故障类型和健康状态。该系统有效地提升了井下排水效率,降低了设备磨损率,减少了煤矿排水系统电能消耗,对煤矿智能化排水系统设计具有一定的参考价值。

基于随机森林回归的船舶特涂维修的日能耗预测

特殊涂装(简称特涂)维修是修船工作的核心内容,能耗的预测是船舶智能能效优化中的一项重要任务。使用随机森林回归(RFR)模型对船舶特涂维修日能耗进行分析,去除异常值、随机化和标准化数据集,然后使用RFR模型对船舶日能耗历史数据进行训练拟和,利用带交叉验证的网格搜索优化RFR模型,使用优化后的RFR模型对船舶特涂维修日能耗数据进行分析,并与其他模型进行对比实验。结果表明,优化后的RFR模型预测效果优于多种其他模型,R2值达93.25%,均方误差明显更低。

基于经验模态分解和随机森林的阀门泄漏模式识别方法

作为核电站的一类关键设备,阀门泄漏会给系统安全、稳定运行造成影响。利用声发射技术识别阀门泄漏,区分出内、外两种不同泄漏模式有助于后续针对性维修,对维修经济性提升具有重要意义。针对上述问题,本文提出了一种基于经验模态分解(EMD)和随机森林的阀门泄漏模式识别方法。首先,对泄漏声发射信号进行EMD处理以获得处于不同频段的分量信号;其次,对各分量信号进行傅里叶变换获取其频谱,并从频谱中提取谱能量比作为特征;最后,基于随机森林算法建立智能识别模型以实现内漏和外漏的自动识别。利用试验数据对方法进行了验证,结果表明,该方法提取的谱能量比特征能够量化内漏、外漏两种模式下声发射信号频谱差异,建立的基于随机森林的模型能够有效实现两种泄漏模式的识别。

西北退化防护林可持续利用模式研究

本研究针对我国西北地区退化防护林可持续利用的迫切需求,从当地对生物质资源的实际需求和防护林退化残次林特点出发,分别提出了残次灌木林和乔木林利用技术方案,这2种方案能为加工生物质成型燃料、牧草饲料、中草药等提供高品质原料,具有因地制宜、产品多样和循环利用的优势,能带来显著的林业增产、农民增收、生态环境改善等多重效果,并能最大程度地减少政府初投资、带动社会资本投入,为我国西北及其他地区退化防护林的利用提供了一种切实可行的可持续模式。

基于文本特征能量编码的多模态语声情感识别

能量是情感表达重要的特征之一,说话时不同的文字有着各自的能量值,反映了说话者不同的情感状态。而把语声转录成文本的过程中,每个文字表达的能量信息并不包含在内,在提取文本特征的时候导致能量信息丢失。故对于文本模态,该文提出并设计了一种能量编码,将语声信号的每个词、每个停顿的能量值添加到转录文本中,使文本特征包含能量信息,并通过DC-BERT模型获取话语级文本特征。对于语声模态,利用OpenSMILE工具箱,提取语声中的浅层声学特征,采用随机森林算法,选取情感特征重要度靠前的1000维特征作为新的特征集。通过Transformer Encoder网络从新的特征集中提取深层特征,并将浅层特征和深层特征融合,形成多层次的语声情感特征。最后,利用基于自注意力机制的双向长短时记忆神经网络进行情感分类。结果表明,该文提出的方法在IEMOCAP四类情感分类中的加权准确率达到了76.49%。

长江流域水-能源-粮食-森林系统耦合协调发展研究

研究长江流域水-能源-粮食-森林(WEFF)系统耦合机理及协调发展时空演变,有助于实现长江流域高质量发展,以便更好地支撑和服务中国式现代化。本文在阐述WEFF系统耦合协调发展机理的基础上,运用综合评价指数模型、耦合协调度模型及全局空间自相关分析测度2003—2021年长江流域WEFF系统综合评价指数、耦合度及耦合协调度,并分析其时空特征,进一步利用灰色预测GM(1,1)模型预测了未来5年发展情况。本文主要结果如下:1)时序变化上,耦合阶段均处于磨合阶段,耦合协调类型从濒临失调转为勉强协调。2)空间差异上,除上海和青海外,各省(直辖市)耦合度均处于磨合阶段,耦合协调度大部分处于濒临失调、勉强协调和初级协调类型;多数年份耦合协调空间集聚状态明显,但空间分布格局缺乏稳定。3)发展模拟上看,基本延续了目前的耦合协调发展变化趋势,但各省(直辖市)发展情况各异。基于以上,统筹推进经济社会发展和生态环境保护、建立跨区域综合协商机制和健全跨部门沟通协商机制有助于保障流域资源安全、维护生态平衡、实现区域可持续发展,进一步推动长江流域高质量发展。

中国居民直接能源消费碳排放时空跃迁特征及影响因素分析

动态把握居民直接能源消费碳排放的时空演化特征及影响因素,对于建立绿色低碳的能源消费模式以及推进碳减排具有重要的理论价值和现实意义。本文基于2000−2021年中国居民直接能源消费量数据、社会经济数据等,利用全局空间自相关、LISA时间路径以及LISA时空跃迁分析中国居民直接能源消费碳排放量整体和局部空间格局演化特征,并使用随机森林模型探究其影响因素。结果表明:①2000−2021年居民直接能源消费碳排放总量和居民人均直接能源消费碳排放量均呈上升趋势,但二者增速均有所下降。②居民人均直接能源消费碳排放量整体上具有较强的空间正相关性且空间关联性有所增强,空间差异呈缩小的变化趋势。局部空间结构较为稳定,且局部空间依赖方向的波动性较弱。省域及其邻域的居民人均直接能源消费碳排放量随时间推移均不发生跃迁的概率较大,空间格局存在一定的路径依赖特征。③能源消费结构对居民人均直接能源消费碳排放量的增长起抑制作用,经济发展水平、城乡居民消费水平、受教育程度和专利授权数量均起促进作用,人口密度和老龄化程度在一定范围内起抑制作用,而超过阈值则起促进作用。能源消费结构对居民人均直接能源消费碳排放量的影响最大,均方误差增量为58.60%;老龄化程度的影响最小,均方误差增量为3.96%。研究显示,中国居民直接能源消费碳排放时空演变及影响因素存在一定差异,因此建议各省份因地制宜构建低碳发展方案,加强区域间碳减排的交流与合作,从能源、人口和经济等方面综合推动居民能耗碳减排,走各具特色的高质量发展道路。

基于变分模态分解能量熵混合时域特征和随机森林的故障电弧检测方法

在家庭生活用电器中,非线性负载电器逐渐增多。这一趋势使基于电弧“零休”特性的传统故障电流检测方法无法准确识别故障现象,因此本文提出一种基于信号时域特征结合变分模态分解固有模态能量熵的随机森林故障电弧识别方法。以线路电流为分析对象,先提取其时频特征量,再采用变分模态分解算法对故障电弧电流进行分解得到模态分量并计算其能量熵。以时域、能量熵特征构成多维特征向量,输入随机森林模型中对信号类型进行分类决策,进而识别故障电弧。实验发现,相比于其他方法,本文所提方法的故障电弧识别准确率可达99%,且适用于多种典型负载和非线性负载工作的低压配电故障电弧识别。

基于残差的分布式光伏发电功率组合预测方法

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为建立一种将扫描电镜/能谱法与多元统计学结合检测粉底液物证的方法。对收集到的50个粉底液样本进行前处理,利用扫描电镜/能谱仪对样本进行分析测试,将50个样本大致分成2大类;结合K-Means聚类对实验数据进行处理,将2大类样本细化分为4类;最后利用随机森林算法搭建分类模型,40个样本作为训练集,10个样本作为测试集,测试集的预测正确率达到86.6%,预测效果良好,可实现样本分类自动化。此方法操作简单,可实现无损检材、分类效果良好,可直接用于公安机关侦查破案,在法庭科学领域有广阔的应用前景。