“双碳”目标下的西安地区绿地植物碳汇矩阵量化与配置模式研究

在“双碳”目标的驱动下,如何遵循绿色低碳途径在城市有限绿地空间条件下实现碳中和,提升城市绿地植物固碳效益成为新时代植物景观营造必须思考和解决的科学问题。结合西安地区不同土地利用类型下的碳储量时空变化状况,提出符合场地生境斑块连通性需求的4种城市绿色空间碳汇矩阵单元,探索植物碳汇在景观全生命周期中的设计过程。通过对西安地区典型绿地样方的持续调研观测,结合i-Tree软件总结出常见乔灌、地被植物的年固碳量,筛选出高固碳型植物种类,总结出适用于公园绿地和居住区绿地的高固碳型灌丛-地被型、地被型植物群落设计模式。依托“高固碳型植物群落数字化平台”对灌丛-地被植物群落碳汇效益进行持续智能监测与模拟,为植物种植设计方案优化和科学决策提供依据。

双碳目标导向下的绿色生态空间碳汇能力优化设计

基于双碳目标背景,从增汇减排的角度提出城市绿色空间低碳生境单元布局模式和提质增效设计途径,是当下解决城市生态问题的关键。以西安白马河公园、西安建筑科技大学南门花园及沣西绿廊等典型绿地为研究对象,通过建立植物群落-土壤下垫面-固碳效能-小气候适应性-生物多样性之间的生态联系,从增加有机物输入和保持土壤有机碳稳定性两方面提升土壤固碳能力,并总结出32种适宜性固碳植物。在此基础上,结合白马河公园实践项目,进一步探究低碳绿地具体优化设计流程,通过划分高固碳强减排、高固碳弱减排、低固碳强减排、低固碳弱减排4种碳汇单元类型提取相应的布局模式,并针对典型区域植物群落样方提出4种高固碳植物群落配置优化设计模式和方法路径,以期为合理布局城市低碳绿色空间提供实际参考。

基于全生命周期的城市小尺度绿地碳平衡

小尺度绿地在城市绿地中分布广、数量多,在全球应对碳排放问题的大背景下对于达成“碳中和”目标具有重要价值。鉴于既有城市小尺度绿地低碳设计缺乏系统性的指导与流程,以景观碳排放和碳汇为切入点,对景观材料生产、景观建造、景观日常使用和景观维护管理全过程进行分析,将小尺度绿地在景观全生命周期中各个阶段的碳排放和碳汇过程进行量化计算比较,认为景观营建中要侧重高固碳地被植物模式的选取和低碳材料的运用,筛选出6种乡土高固碳地被植物群落配置模式,可用于小尺度绿地增加碳汇,减少景观维护管理中的碳排放。提出改善城市小尺度绿地碳平衡的设计及营建方法,总结针对城市小尺度绿地增加碳汇、减少碳排放的关键性策略,为绿色碳汇网络构建提供科学依据与实践指导。

再生涤纶针织物毛坯质量影响因素研究

从原料、设备、织造工艺3方面探讨影响再生涤纶针织物毛坯质量的因素。结果表明,所用原料再生涤纶的粗细不匀、条干不匀、色差等因素影响毛坯的表面质量,会造成面料表面横路、污渍等疵点。设备精度和设备配件影响毛坯的表面质量,设置不当会引起面料表面横路、直条等疵点。编织工艺中的进纱张力、线圈长度和卷布张力也会影响毛坯质量,设置不当会造成面料表面横路、直条及表面风格差异等。同时,针对上述问题给出了合理的参数设置建议。

Effect of Different Nitrogen Fertilizer Application Strategies on Rice Growth and Yield

Nitrogen fertilizer is an important factor for crop production. The N application strategies named as former nitrogen moved backward( FNMB) are tested in three ecological regions to optimize the N application in rice. The dry matter accumulation and distribution,yield and quality are studied to understand the formation of yield and quality of rice under different N application strategies. The result indicates that former nitrogen moved backward( FNMB) can increase tiller number and dry matter accumulation; effective ears and yield can be increased with the increase of fertilization; rational nitrogen application can help to establish scientific group structure,harmonize yield component,and then achieve high ratio of input to output and benefit.

Molecular cloning and identification of mouse epididymis-specific gene mHongl, the homologue of rat HongrES1

Previous studies have shown that rat epididymis-specific gene HongrES1 plays important roles in sperm capacitation and fertility. In this study, we cloned the mouse homologue gene by sequence alignment and RT-PCR methods and designated it as mHongl. The mHongl gene is located on chromosome 12p14, spanning five exons. The cDNA sequence consists of 1257 nucleotides and encodes a 419 amino-acid protein with a predicted N-terminal signal peptide of 20 amino acids. The mHongl mRNA shows similarity with HongrES1 in the expression patterns： （i） specific expression in epididymal tissue, especially in the cauda region; and （ii） androgen-dependence but testicular fluid factor independence. Its protein product shows 71% similarity with HongrES 1 and contains a classical serpin domain as does HongrES1. A polyclonal antibody against mHongl with high specificity and sensitivity was raised. Like HongrES1, the mHongl protein shows a checker-board expression pattern in the epididymal epithelium and is secreted into the epididymal lumen. The mHongl protein shows higher glycosylation than HongrES1. Although both of them are deposited onto the sperm head surface, mHongl is localized to the equatorial segment, which is different from that of HongrES 1. The mHongl protein can be removed from the sperm membrane by high ionic strength and therefore can be classed as an extrinsic membrane protein. Collectively, we conclude that mHongl is the homologue of HongrES1 and the present work paves the way for establishing animal models to elucidate the precise functions of HongrES1 and mHongl.

Topology optimization of turbine disk considering maximum stress prediction and constraints

For the stress-constrained topology optimization of a turbine disk under centrifugal loads,the jagged boundaries of the mesh and the gray densities on the solid/void interfaces could make the calculated stress field inconsistent with the actual value.It may result in overestimating the maximum stress and thus affect the effectiveness of stress constraints.This paper proposes a new method for predicting the maximum stress to overcome the difficulty.In the process,a predicted density is newly defined to obtain stable boundaries with thin layers of gray elements,a transition factor is innovatively proposed to evaluate the effects of intermediate-density elements,two different stiffness penalty schemes are flexibly used to calculate the elastic modulus of elements,and a linear stress penalty is further adopted to relax the stress field of the structure.The proposed approach for predicting the maximum stress value is verified by the analysis of a structure with smooth boundaries and the topology optimization of a turbine disk.An updating scheme of the stress constraint in the topology optimization is also developed using the predicted maximum stress.Some key ingredients affecting the optimization results are discussed in detail.The results prove the effectiveness and efficacy of the proposed maximum stress prediction and developed stress constraint methods.

Study on the pipe friction resistance in long-distance rock pipe jacking engineering

Previous studies on pipe friction resistance are mainly concentrated in the soil layer,whereas the study on that in the rock stratum is limited.To estimate the pipe friction resistance in the rock stratum,the calculation models of pipe friction resistance and their applica-tion conditions were compared first.Then the friction resistance calculation model for pipe jacking in the rock stratum was established and simplified.Lastly,the measured(FM)and the computed(FN)pipe friction resistance was compared to validate the simplified friction resistance calculation model.The following conclusions can be drawn:(1)The existing calculation methods of pipe friction resistance can be well verified in the soil layer but cannot be applied in the rock stratum.(2)Sediment,pipe–rock friction coefficient and mud buoyancy are the main factors affecting the pipe friction resistance in long-distance rock pipe jacking engineering.(3)The simplified calculation model established by Deng et al.can estimate the pipe friction resistance in different rock strata at different jacking stages with satisfac-tory outcomes.Further research on the pipe-rock friction coefficient in different rock strata with different pipe–rock contact conditions merits further investigation to better predict the pipe friction resistance in the rock stratum.The research results have certain practica-bility and can provide a reference for similar projects.

Targeting GATA1 and p2x7r Locus Binding in Spinal Astrocytes Suppresses Chronic Visceral Pain by Promoting DNA Demethylation

Irritable bowel syndrome is a gastrointestinal disorder of unknown etiology characterized by widespread,chronic abdominal pain associated with altered bowel movements.Increasing amounts of evidence indicate that injury and inflammation during the neonatal period have long-term effects on tissue structure and function in the adult that may predispose to gastrointestinal diseases.In this study we aimed to investigate how the epigenetic regulation of DNA demethylation of the p2x7r locus guided by the transcription factor GATA binding protein 1(GATA1)in spinal astrocytes affects chronic visceral pain in adult rats with neonatal colonic inflammation(NCI).The spinal GATA1 targeting to DNA demethylation of p2x7r locus in these rats was assessed by assessing GATA1 function with luciferase assay,chromatin immunoprecipitation,patch clamp,and interference in vitro and in vivo.In addition,a decoy oligodeoxynucleotide was designed and applied to determine the influence of GATA1 on the DNA methylation of a p2x7r CpG island.We showed that NCI caused the induction of GATA1,Ten-eleven translocation 3(TET3),and purinergic receptors(P2X7Rs)in astrocytes of the spinal dorsal horn,and demonstrated that inhibiting these molecules markedly increased the pain threshold,inhibited the activation of astrocytes,and decreased the spinal sEPSC frequency.NCI also markedly demethylated the p2x7r locus in a manner dependent on the enhancement of both a GATA1–TET3 physical interaction and GATA1 binding at the p2x7r promoter.Importantly,we showed that demethylation of the p2x7r locus(and the attendant increase in P2X7R expression)was reversed upon knockdown of GATA1 or TET3 expression,and demonstrated that a decoy oligodeoxynucleotide that selectively blocked the GATA1 binding site increased the methylation of a CpG island in the p2x7r promoter.These results demonstrate that chronic visceral pain is mediated synergistically by GATA1 and TET3 via a DNA-demethylation mechanism that controls p2x7r transcription in spinal dorsal horn astrocytes,and provide a potential therapeutic strategy by targeting GATA1 and p2x7r locus binding.