基于SRP模型的柴达木盆地生态脆弱性评价

生态脆弱性评价是生态治理和修复的重要前提。柴达木盆地是对全球气候变化和人类活动干扰最为敏感的区域之一。通过SRP模型构建柴达木盆地生态脆弱性评价指标体系,基于地理信息技术和遥感技术,采用层次分析法,系统、定量地对柴达木盆地生态脆弱性进行评价。结果表明:1)柴达木盆地微度,轻度类型脆弱区面积为79326 km^(2),占区域总面积的29.28%;中度类型脆弱区面积为67044 km^(2),占区域总面积的24.74%;重度,极度类型脆弱区面积为124613 km^(2),占区域总面积的45.98%。2)柴达木盆地东中西部生态脆弱性表现为“低-中-高”的分布特征。3)柴达木盆地生态脆弱性呈现出强烈的空间正相关特征。

基于SRP模型的新安江流域生态脆弱性评价

开展生态脆弱性与流域生态补偿机制研究,对环境保护与生态修复具有重要意义。选取反映流域生态环境的13个指标,构建生态敏感性-生态恢复力-生态压力度模型(SRP),运用层次分析法并结合专家打分对指标权重进行赋值,在500 m×500 m的栅格尺度下叠加生态红线的划定,对新安江流域2015年和2020年的生态脆弱性进行评价,可为区域生态保护与修复提出对策和建议。结果表明:(1)新安江流域整体生态状况良好,极度脆弱区略高于1%,且与人类活动强度的空间耦合性较好,呈现由中部核心区向周围逐渐衰减的态势;(2)5年间流域生态敏感性向好发展,生态恢复力略有下降,生态压力度维持在稳定态势,整体生态脆弱性结构稳定,脆弱性强度值虽下降了0.12,但86.6%区域的脆弱性等级未发生变化;(3)县域尺度上,脆弱性变化出现“马太效应”,生态环境较脆弱的屯溪区、徽州区和黟县生态脆弱性上升,而生态环境较好的祁门县、休宁县和黄山区生态脆弱性下降;(4)流域生态红线保护区受人类影响较小,基本无极度脆弱区,但仍需加大水源涵养功能保护区的维护力度。

基于SRP模型的内蒙古鄂伦春地区生态脆弱性评价

[研究目的]随着社会经济发展和城镇化率不断提高,当前人类赖以生存的生态环境不断遭受破坏,生态脆弱性日益严峻,生态脆弱性评价已成为了诸多专家学者研究的热点。鄂伦春地区从20世纪产业结构从狩猎业转变为农牧业以来,当地生态环境面临脆弱化的风险。本文通过对鄂伦春地区3期生态脆弱性评价,以期为当地生态环境保护和可持续发展提供科学依据。[研究方法]以内蒙古鄂伦春地区为研究区,基于SRP模型,选取生态恢复力、生态压力度和生态敏感性等3种类型14项指标,利用GIS空间主成分分析(SPCA)和地理探测器(GeoDetector)对鄂伦春地区2000、2010、2020年3期生态脆弱性空间分布、时空演变和驱动因子进行分析。[研究结果](1)鄂伦春地区生态脆弱性整体为良好—轻度脆弱状态,一般性脆弱区在3年的分布面积大致相当,中度和重度脆弱区主要分布在阿里河镇南部、乌鲁布铁镇南部、大杨树镇和古里乡,生态环境总体呈现恶化趋势。(2)鄂伦春地区生态脆弱性在2000-2010年间生态环境呈向良好发展趋势,在2010-2020年间生态环境遭受较大破坏,生态脆弱性明显增加,2020年首次出现重度生态脆弱区面积达111.72 km^(2),占研究区面积的0.51%,生态环境形式严峻。(3)鄂伦春地区生态脆弱性空间分布主要受生物丰度(D2)、景观多样性指数(D3)、高程(D5)、人口密度(D13)等因素影响,在2020年影响因子呈现更加多元化,蔓延度指数(D4)和年均降水量(D12)两个指标对当地生态脆弱性有较强的驱动作用,q值分别为0.737和0.568。[结论]鄂伦春地区2000、2010、2020年3期生态脆弱性总体呈现西北部低、东南部高的显著特征,在2000-2010年间生态环境向良好发展,在2010-2020年间生态环境呈恶化趋势,鄂伦春地区生态脆弱性受人为活动和自然因素共同驱动导致。

基于SRP模型的广东省林地生态脆弱性评价

综合评价广东省林地生态脆弱性等级,掌握广东省林地生态脆弱性的空间分布特征,可为公益林布局优化和生态修复提供理论支持。以广东省第三次全国国土调查成果、林草湿综合监测成果、生态保护红线成果、石漠化监测成果、DEM数据、气象数据、土壤数据等为基础数据,选取人口密度、单位建设用地、耕地占比、植被覆盖度、石漠化严重地区、年均降水量、植物净初级生产力、生物丰度等17个评价指标,基于3S技术,结合SRP模型,采用层次分析方法构建广东省林地脆弱性评价指标体系。结果表明:广东省林地生态环境脆弱性以微度、轻度、中度脆弱为主,占全省林地总面积的92.02%;从行政区划来看,重度脆弱区和极度脆弱区主要分布在清远市、韶关市、梅州市、河源市、肇庆市、茂名市、揭阳市7个市;从空间布局来看,重度脆弱区和极度脆弱区相对集中分布在石漠化区域、水土流失重点治理区和水土流失重点预防区、珠江三角洲人口密集区以及沿海基干林带和周边岛屿。

基于多时相SRP模型的滦州市矿区生态脆弱性评价研究

生态脆弱性评价是衡量矿区生态安全的重要标准之一。为分析滦州市矿区生态脆弱性的时空分布和主要影响因子,依托珠海一号影像数据得到滦州市矿区中心范围的分类结果,从生态敏感性、生态恢复力、生态压力度3个维度,构建了以采场和尾矿库为中心,涵盖三个缓冲圈层的“敏感性-恢复力-压力度”模型(SRP模型),对2010、2015、2019年滦州市矿区的生态脆弱性进行综合评价,最终划定了5个生态脆弱性等级区。评价结果表明:(1)滦州市矿区在空间上以微度和轻度脆弱区为主,在时间上呈现出微度和轻度脆弱区先增加后降低的趋势、中度和中度以上脆弱区先降低后增加的趋势,生态环境总体质量呈向好发展;(2)2010、2015、2019年滦州市矿区生态环境脆弱性总体以微度脆弱为主,分别占69.33%、86.13%、78.89%,重度和极度脆弱区的比例之和均低于5%;(3)从时间和空间变化情况看,采矿、城镇发展,人口、GDP等都是导致滦州市生态脆弱性结果的主要影响因素,矿山对生态脆弱性的影响程度在政策引导作用下逐步减弱,而经济建设对自然的破坏性不容忽视。滦州市矿区2010~2019年3期生态脆弱性整体呈现西北高、东南低的趋势,2010~2015年间生态脆弱性缓和,在2015~2019年间生态脆弱性加重,滦州市矿区生态脆弱性受人为活动和自然因素的共同影响。

基于SRP模型的地质灾害易发区生态脆弱性评价

以甘肃省舟曲县为研究对象,以2010,2015和2020年遥感影像数据、地形数据、气象数据、地质灾害数据以及社会经济数据等为基础,结合SRP模型构建评价体系,采用层次分析法、空间自相关、地理探测器等方法,对舟曲县生态环境脆弱性进行定量评价与分析.结果表明:从县域尺度来看,2010—2020年舟曲县生态处于中等脆弱水平,在空间上呈现“北低南高,东低西高”的特征,时间上呈现“极度、重度脆弱区面积明显减少,中度脆弱区面积显著增加”趋势,整体向好趋势明显;从乡镇尺度来看,生态脆弱性状况均呈好转趋势,各乡镇生态脆弱性等级变化以极度、重度脆弱区减少,中度脆弱区增加为主;生态脆弱性空间集聚效应减弱,高高集聚类型乡镇由4个减少至3个,低聚集类型乡镇由1个增加至2个;生态脆弱性分布与变化主要受土壤、气象、地形地貌、人类活动以及地质灾害等因素综合影响,其中年降水量、地质灾害易发点密度和距离道路距离3个因子解释力最强,地形起伏度、坡度和距离河流距离3个因子解释力最弱.

Evolution of Biofilm and Its Effect on Microstructure of Mortar Surfaces in Simulated Seawater

To explore the role of biofilm formation on the corrosion of marine concrete structures, we investigated the attachment of biofilm on mortar surfaces in simulated seawater and the influence of biofilm on the microstructure of mortar surfaces. The results show that the evolution of biofilm on mortar surfaces in simulated seawater is closely related to the corrosion suffered by the mortar, and the process of biofilm attachment and shedding is continuous and cyclical. It is found that the specimens in the absence of biofilm attachment are more severely eroded internally by the corrosive medium in simulated seawater than those in the presence of biofilm attachment. For the specimens without biofilm attachment, after 60 days, gypsum forms,and after 120 days, the number of pores in the mortar is reduced. In contrast, for the specimens in the presence of biofilm attachment, gypsum could only be detected after 90 days, and fewer pores are filled. Therefore, the formation of biofilm could delay the invasion of the corrosive medium into the interior of mortar during the evolution of biofilm on mortar surfaces, mitigating the corrosion of mortars in seawater.

An Investigation into the Performances of Cement Mortar Incorporating Superabsorbent Polymer Synthesized with Kaolin

Cement-based materials are fundamental in the construction industry,and enhancing their properties is an ongoing challenge.The use of superabsorbent polymers(SAP)has gained significant attention as a possible way to improve the performance of cement-based materials due to their unique water-absorption and retention properties.This study investigates the multifaceted impact of kaolin intercalation-modified superabsorbent polymers(K-SAP)on the properties of cement mortar.The results show that K-SAP significantly affects the cement mortar’s rheological behavior,with distinct phases of water absorption and release,leading to changes in workability over time.Furthermore,K-SAP alters the hydration kinetics,delaying the exothermic peak of hydration and subsequently modifying the heat release kinetics.Notably,K-SAP effectively maintains a higher internal relative humidity within the mortar,reducing the autogenous shrinkage behavior.Moreover,K-SAP can have a beneficial effect on pore structure and this can be ascribed to the internal curing effect of released water from K-SAP.

Influence of Recycled Concrete Fine Powder on Durability of Cement Mortar

In this paper,the durability of cement mortar prepared with a recycled-concrete fine powder(RFP)was examined;including the analysis of a variety of aspects,such as the carbonization,sulfate attack and chloride ion erosion resistance.The results indicate that the influence of RFP on these three aspects is different.The carbonization depth after 30 days and the chloride diffusion coefficient of mortar containing 10%RFP decreased by 13.3%and 28.19%.With a further increase in the RFP content,interconnected pores formed between the RFP particles,leading to an acceleration of the penetration rate of CO_(2)and Cl^(−).When the RFP content was less than 50%,the corrosion resistance coefficient of the compressive strength of the mortar was 0.84-1.05 after 90 days of sulfate attack.But the expansion and cracking of the mortar was effectively alleviated due to decrease of the gypsum production.Scanning electron microscope(SEM)analysis has confirmed that 10%RFP contributes to the formation of a dense microstructure in the cement mortar.

Analysis of Calcined Red Mud Properties and Related Mortar Performances

Red mud(RM)is a low-activity industrial solid waste,and its utilization as a resource is currently a hot topic.In this study,the micro characteristics of red mud at different calcination temperatures were analyzed using X-ray diffraction and scanning electron microscopy.The performance of calcined red mud was determined through mortar strength tests.Results indicate that high-temperature calcination can change the mineral composition and microstructure of red mud,and increase the surface roughness and specific surface area.At the optimal temperature of 700°C,the addition of calcined red mud still leads to a decrease in mortar strength,but its activity index and flexural coefficient increase by 16.2%and 11.9%with respect to uncalcined red mud,reaching values of 0.826 and 0.974,respectively.Compared with the control group,the synergistic activation of calcined red mud with slag can increase the compressive and flexural strength of the mortar by 12.9%and 1.5%,reaching 8.7 and 62.4 MPa,respectively.Correspondingly,the activity index and flexural coefficient of the calcined RM and GGBS(Ground Granulated Blast furnace Slag)mixtures also increase to 1.015 and 1.130,respectively.

Effect of Partial Replacement of Fly Ash by Decoration Waste Powder on the Fresh and Mechanical Properties of Geopolymer Masonry Mortar

This study aims to investigate the feasibility of using decoration waste powder(DWP)as a partial replacement for fly ash(FA)in the preparation of geopolymer masonry mortar,and to examine the effect of different DWP replacement rates(0%-40%)on the fresh and mechanical properties of the mortar.The results showed that each group of geopolymer masonry mortar exhibited excellent water retention performance,with a water retention rate of 100%,which was due to the unique geopolymer mortar system and high viscosity of the alkaline activator solution.Compared to the control group,the flowability of the mortar containing lower contents of DWP(10%and 20%)was higher.However,as the DWP replacement rate further increased,the flowability gradually decreased.The DWP could absorb the free water in the reaction system of geopolymer mortar,thereby limiting the occurrence of geopolymerization reaction.The incorporation of DWP in the mortar resulted in a decrease in compressive strength compared to the mortar without DWP.However,even at a replacement rate of 40%,the compressive strength of the mortar still exceeded 15 MPa,which met the requirements of the masonry mortar.It was feasible to use DWP in the geopolymer masonry mortar.Although the addition of DWP caused some performance loss,it did not affect its usability.

Study on physical and mechanical properties of cement asphalt emulsified mortar under track slab

Purpose–During the construction process of the China Railway Track System(CRTS)I type filling layer,the nonwoven fabric bags have been used as grouting templates for cement asphalt(CA)emulsified mortar.The porous structure of nonwoven fabrics endowed the templates with breathability and water permeability.The standard requires that the volume expansion rate of CA mortar must be controlled within 1%–3%,which can generate expansion pressure to ensure that the cavities under track slabs are filled fully.However,the expansion pressure caused some of the water to seep out from the periphery of the filling bag,and it would affect the actual mix proportion of CA mortar.The differences in physical and mechanical properties between the CA mortar under track slabs and the CA mortar formed in the laboratory were studied in this paper.The relevant results could provide important methods for the research of filling layer materials for CRTS I type and other types of ballastless tracks in China.Design/methodology/approach–During the inspection of filling layer,the samples of CA mortar from different working conditions and raw materials were taken by uncovering the track slabs and drilling cores.The physical and mechanical properties of CA mortar under the filling layer of the slab were systematically analyzed by testing the electrical flux,compressive strength and density of mortar in different parts of the filling layer.Findings–In this paper,the electric flux,the physical properties and mechanical properties of different parts of CA mortar under the track slab were investigated.The results showed that the density,electric flux and compressive strength of CA mortar were affected by the composition of raw materials for dry powders and different parts of the filling layer.In addition,the electrical flux of CA mortar gradually decreased within 90 days’age.The electrical flux of samples with the thickness of 54 mm was lower than 500 C.Therefore,the impermeability and durability of CA mortar could be improved by increasing the thickness of filling layer.Besides,the results showed that the compressive strength of CA mortar increased,while the density and electric flux decreased gradually,with the prolongation of hardening time.Originality/value–During 90 days’age,the electrical flux of the CA mortar gradually decreased with the increase of specimen thickness and the electrical flux of the specimens with the thickness of 54 mm was lower than 500 C.The impermeability and durability of the CA mortar could be improved by increasing the thickness of filling layer.The proposed method can provide reference for the further development and improvement of CRTS I and CRTS II type ballastless track in China.

Influence of Ultra Fine Glass Powder on the Properties and Microstructure of Mortars

This study focuses on the effect of ultrafine waste glass powder on cement strength,gas permeability and pore structure.Varying contents were considered,with particle sizes ranging from 2 to 20μm.Moreover,alkali activation was considered to ameliorate the reactivity and cementitious properties,which were assessed by using scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDS),and specific surface area pore size distribution analysis.According to the results,without the addition of alkali activators,the performance of glass powder mortar decreases as the amount of glass powder increases,affecting various aspects such as strength and resistance to gas permeability.Only 5%glass powder mortar demonstrated a compressive strength at 60 days higher than that of the control group.However,adding alkali activator(CaO)during hydration ameliorated the hydration environment,increased the alkalinity of the composite system,activated the reactivity of glass powder,and enhanced the interaction of glass powder and pozzolanic reaction.In general,compared to ordinary cement mortar,alkali-activated glass powder mortar produces more hydration products,showcases elevated density,and exhibits improved gas resistance.Furthermore,alkali-activated glass powder mortar demonstrates an improvement in performance across various aspects as the content increases.At a substitution rate of 15%,the glass powder mortar reaches its optimal levels of strength and resistance to gas permeability,with a compressive strength increase ranging from 28.4%to 34%,and a gas permeation rate reduction between 51.8%and 66.7%.

SRP72基因突变致骨髓衰竭综合征1型1例

骨髓衰竭综合征1型(BMFS1)是一种罕见的骨髓衰竭性疾病,由SRP72(NM_006947.4)基因突变所致,需要进行造血干细胞移植(HSCT)治疗。基因检测对该病的诊断和治疗方法选择至关重要。本文报道1例由SRP72基因c.1502+1G>A自发突变致BMFS1的患儿,并顺利实施HSCT治疗,患儿最终痊愈。本研究发现的c.1502+1G>A变异,未检索到与BMFS1相关的文献报道。本例患儿的发现扩展了SRP72基因致病性变异谱和表型谱,为BMSF1的早期诊断和正确治疗的选择提供了典型案例。

Substitution of Aggregates in Concrete and Mortar with Coltan Mining Waste: Mechanical, Environmental, and Economic Impact Case Study

The mining process involves drilling and excavation, resulting in the production of waste rock and tailings. The waste materials are then removed and stored in designated areas. This study aims to evaluate the mechanical strength and the environmental and economic impact of using Coltan Mining Waste (CMW) as a substitute for aggregates in concrete and mortar production. To achieve this, the CMW needs to be characterised. The Dreux Gorisse method was primarily used to produce concrete with a strength of 20 MPa at 28 days. The mortars, on the other hand, were formulated according to the NF P 18-452 standard. The environmental impact of using CMW as substitutes for natural aggregates in the production of concrete and mortar was analysed using SimaPro software. The results showed that mortars and concrete made with CMW have comparable compressive strengths to the reference mortar and concrete;reduce the negative impact on ecosystem quality, human health, resources, and climate change. It has also been shown that the substitution of aggregates by CMW reduces the cost of concrete and mortar as a function of the distance from the aggregate footprint.

Research Analysis on the Microscopic Properties and Damping Performance of Carbon Nanomaterial-Modified Cement Mortar

The application of carbon nanomaterials, particularly graphene and carbon nanotubes, in cement-based composites is highly significant. These materials demonstrate the multifunctionality of carbon and offer extensive possibilities for technological advancements. This research analyzes how the integration of graphene into cement-based composites enhances damping and mechanical properties, thereby contributing to the safety and durability of structures. Research on carbon nanomaterials is ongoing and is expected to continue driving innovation across various industrial sectors, promoting the sustainable development of building materials.

The Effect of Graphene Oxide on Mechanical Properties of Cement Mortar

Cement is widely used in engineering applications,but it has both the characteristics of high brittleness and poor bending resistance.In this paper,the effects of different amounts ofgraphene oxide on the flexural strength and compressive strength of cement mortar were studied by doping a certain amount of graphene oxide with cement mortar,and the strengthening mechanism of graphene oxide on cement mortar was obtained through microstructure detection.It is found that graphene oxide has a significant enhancement effect on the macroscopic mechanical properties of cement mortar,and graphene oxide provides nano-nucleation sites and growth templates for cement mortar,accelerates the hydration process,reduces the voids between hydration products,greatly increases the compactness,and improves the macroscopic properties of cement-based materials.

矿产资源开发视角下基于SRP模型的秦岭“生命共同体”生态脆弱性评价

生态脆弱性评价作为开展生态保护的依据之一,对于区域生态建设具有重要作用。为系统分析秦岭“生命共同体”生态脆弱性的时空分布特征和主要驱动因子,从山水林田湖出发,根据山水林田湖系统在秦岭地区的典型性,构建矿产资源开发视角下秦岭“生命共同体”概念模型,并利用生态敏感性-生态恢复力-生态压力度(SRP)模型选取32个评价指标构建秦岭“生命共同体”评价指标体系,结合主成分分析(PCA)法对秦岭“生命共同体”2013年、2017年、2020年3期生态脆弱性进行定量评价。结果表明:(1)矿产资源开发视角下秦岭“生命共同体”的生态脆弱性空间分布呈东北高、西南低的特征,在3期内经历了从以极度脆弱为主到以微度脆弱为主,整体上生态脆弱性呈好转趋势,但渭南市生态脆弱性程度趋向严重;(2)工业废弃物排放量、采矿业能源消耗量、耕地面积、地区生产总值、人口密度、环保投资、水库库容是影响秦岭“生命共同体”生态脆弱性的主要因素。该研究结果可为秦岭“生命共同体”建设和生态修复与保护提供理论依据。

快速SRP-PHAT多声源定位算法

相位变换加权指向响应功率(SRP-PHAT)算法在低信噪比和强混响环境下具有较好的鲁棒性,但是空间遍历带来的海量计算给其声源实时定位带来了挑战。提出了一种适用于多声源的随机区域收缩SRP-PHAT算法,通过最小描述长度(MDL)准则确定声源数量,利用K-means聚类算法进行空间区域划分,且引入瑞利限驱动的K-means聚类纠错机制,通过随机区域收缩算法进行空间区域快速收缩,利用波束主瓣宽度准则判别和界定有效声源,实现多声源定位。结果表明:针对3个声源和信噪比0 dB的情形,所提算法能够在保证定位准确率高于95%的前提下,提高30倍的计算效率,实现快速多声源定位。

基于SRP模型榆林市生态脆弱性评价及时空演变研究

文章以2000年和2020年2个时期的榆林市为研究对象,基于SRP(敏感性-恢复力-压力度)概念模型选取13个指标构建生态脆弱性评价指标体系,采用空间主成分分析法计算生态脆弱指数,通过莫兰指数和地理探测器等方法揭示生态脆弱性的时空分布特征及演变驱动因素。结果表明:研究区生态敏感性总体上表现出西北高,东南低的空间分异特点。2000—2020年研究区各等级生态脆弱性相互转化的面积总和为23619.93km^(2),中度以上脆弱区转入更低度脆弱区的面积明显高于微、轻度脆弱区转入更高度脆弱区方向转移的趋势。研究区生态脆弱性空间集群现象呈缓慢上升趋势,“高-高”聚集型地区在收缩,“低-低”聚集型区域不断外扩。两个时期研究区生态脆弱性主要驱动因子为年降水量、植被覆盖度。总之,虽然2000—2020年研究区生态脆弱性程度呈现好转趋势,但生态环境压力仍不容小觑。为榆林市的资源利用、生态保护与生态恢复提出合理的措施,实现资源、环境和社会经济的和谐发展。