1980—2030年石羊河流域生态系统碳储存服务对土地利用变化的响应

陆地生态系统碳储量是表征碳储存服务的重要指标,其变化与土地利用变化存在着密不可分的关系。预测未来土地利用变化对认识区域生态系统服务及其变化具有重要的意义。利用石羊河流域1980—2020年土地利用数据,运用InVEST模型和FLUS模型,探究了石羊河流域在过去40年间和未来自然变化、生态保护、耕地保护3种情景下的土地利用变化对碳储量的影响。结果表明:石羊河流域在1980—2020年间耕地、草地、建设用地呈增加趋势,林地、水域、未利用地呈减少的趋势。40年间石羊河流域碳储量增加了7.98×10^(6)t,增幅为1.44%。石羊河流域碳储量呈现明显的空间分异,碳储量较高的地区主要分布在上游祁连山区和中下游绿洲地区,这种分布格局与流域内土地利用类型的空间分布密切相关。至2030年,自然变化、生态保护、耕地保护情景下石羊河流域碳储量分别为563×10^(6)t、563.43×10^(6)t、564.98×10^(6)t,较2020年分别增加了0.45%、0.53%和0.80%,其中生态保护情景与其他两种情景相比既保护了生态环境还保障了生产,对未来土地利用规划有一定指导意义。

城市活力视角下全国地级资源型城市转型效率评价研究

从城市活力这个新颖的评价角度能够很好地体现城市发展的质量和潜力,契合中国转向高质量发展阶段的时代背景。在分析我国资源型城市活力时空分布格局的基础上,利用对抗型交叉DEA模型构建城市活力视角下的资源型城市转型效率评价体系,对2008—2018年我国114个地级资源型城市的转型效率进行定量评价,并使用Global Malmquist-Luenberger指数研究了11年间转型效率的动态变化及其因素分解。结果表明:(1)研究期间我国资源型城市整体的城市活力在迅速增长的同时,表现出明显的地区分异。(2)各城市的转型效率排名发生巨大变动,转型效果差距明显,不同地区和不同类型城市的转型效率体现出很大的差异性。(3)自2013年《全国资源型城市可持续发展规划(2013—2020年)》发布后,我国资源型城市的转型效率对比之前有了明显提高,但大部分资源型城市转型效率进步的主要驱动因素是技术进步,技术效率变化的作用较小,因此需要重视资源投入的优化配置。

宣肺败毒颗粒临床应用专家共识

宣肺败毒颗粒是在经典名方基础上化裁而成的用于治疗新型冠状病毒感染的有效方药。为进一步规范临床医师对宣肺败毒颗粒的合理使用,提高临床疗效,提高合理用药水平,发挥更大作用,特邀请来自临床一线专家,针对宣肺败毒颗粒的功能主治、用法用量、不良反应及注意事项等进行讨论,形成共识。共识认为:宣肺败毒颗粒具有宣肺化湿、清热透邪、泻肺解毒的功效;可用于治疗新冠病毒感染轻型、普通型、重型患者及流感等其他常见上呼吸道感染性疾病;急性气管炎-支气管炎及社区获得性下呼吸道感染性疾病等属湿毒郁肺者;可缓解慢性阻塞性肺疾病急性加重所引发的咳嗽、咯痰等症状,临床疗效确切,安全性好。按照循证医学原则,该专家共识将会定期进行更新。

Creep feed grinding induced gradient microstructures in the superficial layer of turbine blade root of single crystal nickel-based superalloy

The service performance of the turbine blade root of an aero-engine depends on the microstructures in its superficial layer.This work investigated the surface deformation structures of turbine blade root of single crystal nickel-based superalloy produced under different creep feed grinding conditions.Gradient microstructures in the superficial layer were clarified and composed of a severely deformed layer(DFL)with nano-sized grains(48–67 nm)at the topmost surface,a DFL with submicron-sized grains(66–158 nm)and micron-sized laminated structures at the subsurface,and a dislocation accumulated layer extending to the bulk material.The formation of such gradient microstructures was found to be related to the graded variations in the plastic strain and strain rate induced in the creep feed grinding process,which were as high as 6.67 and 8.17×10^(7)s^(−1),respectively.In the current study,the evolution of surface gradient microstructures was essentially a transition process from a coarse single crystal to nano-sized grains and,simultaneously,from one orientation of a single crystal to random orientations of polycrystals,during which the dislocation slips dominated the creep feed grinding induced microstructure deformation of single crystal nickel-based superalloy.

A nonlinear creep damage model for gelled waxy crude

Yielding behaviors of waxy crude oil is one of the key issues of flow assurance challenges. The yielding of waxy crude under constant stress is actually a creep process of strain accumulation to structural failure,to describe the process completely and accurately is the basis of numerical simulation of restart process of the pipeline. The creep and yield behaviors of two gelled waxy crudes were investigated experimentally under different constant applied stresses. The results clearly show that the creep process of waxy crude is related to the applied stress and time. The greater the applied stress, and the longer the loaded time, the more obvious the nonlinear features. Based on the fractional calculus theory, a fractional viscous element was developed to describe the decelerated and steady creep process of gelled waxy crude. On the basis of the damage theory, an elastic damage element was proposed to describe the accelerated creep after the yielding. According to the idea of mechanical analogy, a nonlinear creep model was established by a fractional viscous element, an elastic damaged element, and an elastic element in series, which can accurately describe the whole creep and yielding process of gelled waxy crude.

Transcriptome Analysis of Ten-DPA Fiber in an Upland Cotton (<i>Gossypium hirsutum</i>) Line with Improved Fiber Traits from Phytochrome A1 RNAi Plants

Silencing phytochrome A1 gene (PHYA1) by RNA interference in Upland cotton (Gossypium hirsutum L. cv. Coker 312) had generated PHYA1 RNAi lines with improved fiber quality (longer, stronger and finer fiber). To reveal molecular mechanisms that govern fiber development with positive fiber traits, a study of global gene expression profiling of 10-DPA fibers in a PHYA1 RNAi line and its parent Coker 312 was conducted by high-throughput RNA sequencing. A comparative analysis of transcriptomes between the two lines had identified 142 genes that were differentially expressed in the 10-DPA fiber of the RNAi line. Gene Ontology analysis showed that these differentially expressed genes were mainly involved in metabolic pathways, heterocyclic/organic cyclic compound binding and multiple enzyme activities, and cell structures which were reported to play important roles in fiber development. Twenty-eight KEGG pathways were mapped for the 142 genes, and the pathways related to glycolysis/gluconeogenesis and pyruvate metabolism were the most abundant and followed by cytochrome P450-involved pathways, suggesting that fiber improvement could be through the regulation of proteins involved in cytochrome P450 pathways. Genes encoding WRKY transcription factors, sucrose synthase, xyloglucan endotransglucosylase hydrolase, udp-glucuronate: xylan alpha-glucuronosyltransferase, and genes involved in lipid metabolism and ABA/brassinosteroid signal transduction pathways were found differentially expressed in the RNAi line. These genes have direct impacts on cotton fiber quality. The results of this study elucidate molecular signatures and possible mechanisms of fiber improvement in the background of PHYA1 RNAi in cotton and should help for future fine-tuning and programming of cotton fiber development.

Discussion on “One Belt One Road” Construction and International Financial Cooperation

Under the grand economic vision of opening up and cooperation among countries,the world economy is gradually recovering,and economic and trade exchanges between countries are increasing,which is an important sign of sound economic development.At the same time,we need the joint efforts of all countries to move towards the goal of mutual benefit and common development.We should fully develop one of the"one belt one road"in the economic construction.At the same time,we need to deepen economic cooperation,improve the investment and financing system and credit system,and China International Finance is particularly important.International financial cooperation is one of the difficulties things and“One belt one road”is the same.The financial market's influence on the economic outflow of funds is not to be ignored.Based on this background,one will take the"one belt one road"as the starting point to explore the problems of international financial cooperation.

Efficient Expressive Attribute-Based Encryption with Keyword Search over Prime-Order Groups

Attribute-based encryption with keyword search(ABEKS)is a novel cryptographic paradigm that can be used to implementfine-grained access control and retrieve ciphertexts without disclosing the sensitive information.It is a perfect combination of attribute-based encryption(ABE)and public key encryption with keyword search(PEKS).Nevertheless,most of the existing ABEKS schemes have limited search capabilities and only support single or simple conjunctive keyword search.Due to the weak search capability and inaccurate search results,it is difficult to apply these schemes to practical applications.In this paper,an effi-cient expressive ABEKS(EABEKS)scheme supporting unbounded keyword uni-verse over prime-order groups is designed,which supplies the expressive keyword search function supporting the logical connectives of“AND”and“OR”.The proposed scheme not only leads to low computation and communica-tion costs,but also supports unbounded keyword universe.In the standard model,the scheme is proven to be secure under the chosen keyword attack and the cho-sen plaintext attack.The comparison analysis and experimental results show that it has better performance than the existing EABEKS schemes in the storage,com-putation and communication costs.

Transcriptome Analysis of Ten Days Post Anthesis Elongating Fiber in the Upland Cotton (<i>Gossypium hirsutum</i>) Chromosome Substitution Line CS-B25

A chromosome substitution line, CS-B25, was developed by the substitution of chromosome pair 25 of Gossypium hirsutum TM-1 with the homologous pair of chromosome 25 from G. barbadense, a double haploid Pima 3-79 line. CS-B25 has improved fiber traits compared to its parent TM-1. To explore the molecule mechanisms underlying improved fiber traits, deep sequencing of total RNA was used to compare gene expression in fibers of CS-B25 and TM-1 at 10 days post anthesis (10-DPA). A total of 1872 differentially expressed genes (DEGs) were detected between the two lines, with 1175 up-regulated and 697 down-regulated in CS-B25. Gene Ontology (GO) enrichment analysis of the expression data by Generally Applicable Gene-set Enrichment (GAGE) and ReviGO indicated that the most prevalent Biological Process GO terms associated with DEGs included DNA-templated transcription, response to oxidative stress, and cellulose biosynthesis. Enriched Molecular Function GO terms included structural constituents of cytoskeleton, peroxidase activity, cellulose synthase (UDP-forming) activity, and transcription regulatory region sequence-specific DNA binding factors. GAGE was also used to find enriched KEGG pathways, and the highly represented pathways were Biosynthesis of Amino Acids, Starch and Sucrose Metabolism, Phenylpropanoid Biosynthesis, Protein Processing in Endoplasmic Reticulum, and Plant Hormone Signal Transduction. Many of the identified DEGs are involved in cytoskeleton and cell wall metabolism. The results of gene expression data have provided new insight into the molecular mechanisms of fiber development during the fiber elongation stage and would offer novel candidate genes that may be utilized in cotton fiber quality improvement.

The AaBBX21–AaHY5 module mediates light-regulated artemisinin biosynthesis in Artemisia annua L.

The sesquiterpene lactone artemisinin is an important anti-malarial component produced by the glandular secretory trichomes of sweet wormwood(Artemisia annua L.).Light was previously shown to promote artemisinin production,but the underlying regulatory mechanism remains elusive.In this study,we demonstrate that ELONGATED HYPOCOTYL5(HY5),a central transcription factor in the light signaling pathway,cannot promote artemisinin biosynthesis on its own,as the binding of AaHY5 to the promoters of artemisinin biosynthetic genes failed to activate their transcription.Transcriptome analysis and yeast two-hybrid screening revealed the B-box transcription factor AaBBX21 as a potential interactor with AaHY5.AaBBX21 showed a trichome-specific expression pattern.Additionally,the AaBBX21–AaHY5 complex cooperatively activated transcription from the promoters of the downstream genes AaGSW1,AaMYB108,and AaORA,encoding positive regulators of artemisinin biosynthesis.Moreover,AaHY5 and AaBBX21 physically interacted with the A.annua E3 ubiquitin ligase CONSTITUTIVELY PHOTOMORPHOGENIC 1(COP1).In the dark,AaCOP1 decreased the accumulation of AaHY5 and AaBBX21 and repressed the activation of genes downstream of the AaHY5–AaBBX21 complex,explaining the enhanced production of artemisinin upon light exposure.Our study provides insights into the central regulatory mechanism by which light governs terpenoid biosynthesis in the plant kingdom.

Adsorption and sensing characteristics of insulating gas C4F7N on 3d late transition metal-phthalocyanine:Theoretical and experimental study

Heptafluoroisobutyronitrile(C_(4)F_(7)N)is being considered as a promising alternative to the greenhouse gas SF6 in the electrical industry.However,its biotoxicity necessitates the development of gas sensing technology to detect leaked C_(4)F_(7)N.A combination of density functional theory and experiments was employed to evaluate the adsorption and sensing performance of different metal-phthalocyanines as potential sensing materials for C_(4)F_(7)N detection.The study included exploring adsorption configurations with adsorption energies,electron transfer,and adsorption distance,as well as comparisons of electronic properties,electron distribution,and density of states(DOS)among the MPcs.Furthermore,gas sensing experiments were conducted using different MPcs to detect 25-100 ppm C_(4)F_(7)N.The results revealed that Mn-Pc,Fe-Pc,Co-Pc,and Zn-Pc exhibited considerable chemical interactions,while Ni-Pc and Cu-Pc showed weaker adsorption strength.These findings were further elucidated based on the electron density and DOS of atomic orbitals.Moreover,gas sensing experiments indicated that Co-Pc demonstrated a higher response compared to Fe-Pc at the same concentration of C_(4)F_(7)N.Overall,the theoretical and experimental insights offer valuable guidance for C_(4)F_(7)N detection and provide a systematic approach to screen and explore organometallic polymer-based gas sensors applicable in various fields.

基于IRSEI的石羊河流域生态环境质量时空变化及驱动力分析

基于绿度、湿度、热度、盐度、荒漠化程度五个指标,构建了改进遥感生态指数IRSEI,提出了完全基于遥感数据的石羊河流域生态环境质量综合评价方法。以2000-2020年为时间序列,对石羊河流域生态环境质量时空分布特征和驱动因素进行了分析。结果表明:石羊河流域生态环境质量整体偏低,空间差异显著;近20年间,流域生态环境质量整体有所改善,绿洲边缘、上游林地和草地区域改善较显著;流域生态环境质量受自然因素和人为因素共同影响,年平均气温、年降水量、海拔、土地利用类型是流域生态环境质量空间分异的主要驱动力因子,驱动因子之间的交互作用表现为双因子增强和非线性增强,土地利用类型和其他驱动因子的交互作用最为明显。

基于天然低共熔溶剂的甜叶菊中甜菊糖绿色提取方法及优化

尝试利用天然低共熔溶剂(NADES)提取甜叶菊(Stevia rebaudiana)中的甜菊糖,探索一种高效、绿色和环保的甜菊糖提取新方法。以甜叶菊干叶为原料,对照传统提取溶剂水,以甜菊糖中甜菊苷和莱鲍迪苷A的提取浓度作为指标,筛选出最优的NADES提取配方,然后通过Box-Behnken响应面法对NADES提取甜叶菊中甜菊糖的工艺条件进行筛选优化。结果表明,提取效率最高的NADES配方为1,2-丙二醇:甘油:水=8:1:1(v/v/v),提取的甜菊苷浓度为2.59 mg·mL^(-1),比水提取高16.40%,提取的莱鲍迪苷A浓度为1.06 mg·mL^(-1),比水提取高12.62%;通过响应面法得到最优提取条件:提取时间90分钟,提取温度60℃,超声功率为80 J·s^(-1),预测甜菊苷提取浓度为3.49 mg·mL^(-1),莱鲍迪苷A提取浓度为1.43 mg·mL^(-1),与实验验证值(甜菊苷浓度为3.48 mg·mL^(-1),莱鲍迪苷A浓度为1.42 mg·mL^(-1))接近。在最优条件下,甜菊苷提取浓度比初始条件提高了34.36%,莱鲍迪甘A提取浓度比初始条件提高了33.96%。NADES绿色环保,且提取效率高于传统溶剂,可用于甜叶菊中甜菊糖的绿色提取;同时,该提取方法可为后续推广至其它大宗经济植物类天然产物的绿色工业生产提供参考。

Grinding force and surface quality in creep feed profile grinding of turbine blade root of nickel-based superalloy with microcrystalline alumina abrasive wheels

Creep feed profile grinding of the fir-tree blade root forms of single crystal nickel-based superalloy was conducted using microcrystalline alumina abrasive wheels in the present study. The grinding force and the surface quality in terms of surface topography, subsurface microstructure,microhardness and residual stress obtained under different grinding conditions were evaluated comparatively. Experimental results indicated that the grinding force was influenced significantly by the competing predominance between the grinding parameters and the cross-sectional root workpiece profile. In addition, the root workpiece surface, including the root peak and valley regions, was produced with the large difference in surface quality due to the nonuniform grinding loads along the root workpiece profile in normal section. Detailed results showed that the surface roughness, subsurface plastic deformation and work hardening level of the root valley region were higher by up to25%, 20% and 7% in average than those obtained in the root peak region, respectively, in the current investigation. Finally, the superior parameters were recommended in the creep feed profile grinding of the fir-tree blade root forms. This study is helpful to provide industry guidance to optimize the machining process for the high-valued parts with complicated profiles.

Characterization of the aerosol chemical composition during the COVID-19 lockdown period in Suzhou in the Yangtze River Delta,China

To control the spread of COVID-19,rigorous restrictions have been implemented in China,resulting in a great reduction in pollutant emissions.In this study,we evaluated the air quality in the Yangtze River Delta during the COVID-19 lockdown period using satellite and ground-based data,including particle matter(PM),trace gases,water-soluble ions(WSIs) and black carbon(BC).We found that the impacts of lockdown policy on air quality cannot be accurately assessed using MODIS aerosol optical depth(AOD) data,whereas the tropospheric nitrogen dioxide(NO_(2)) vertical column density can well reflect the influences of these restrictions on human activities.Compared to the pre-COVID period,the PM_(2.5),PM_(10),NO_(2),carbon monoxide(CO),BC and WSIs during the lockdown in Suzhou were observed to decrease by 37.2%,38.3%,64.5%,26.1%,53.3% and 58.6%,respectively,while the sulfur dioxide(SO_(2)) and ozone(O_(3)) increased by 1.5% and 104.7%.The WSIs ranked in the order of NO_(3)~->NH_(4)^(+)>SO_(4)^(2-)>Cl~->Ca^(2+)>K^(+)>Mg^(2+)>Na + during the lockdown period.By comparisons with the ion concentrations during the pre-COVID period,we found that the ions NO 3-,NH 4 +,SO_(4)^(2-),Cl~-,Ca^(2+),K^(+) and Na^(+) decreased by 66.3%,48.8%,52.9%,56.9%,57.9% and 76.3%,respectively,during the lockdown,in contrast to Mg^(2+),which increased by 30.2%.The lockdown policy was found to have great impacts on the diurnal variations of Cl~-,SO_(4)^(2-),Na^(+) and Ca^(2+).

An investigation on machined surface quality and tool wear during creep feed grinding of powder metallurgy nickel-based superalloy FGH96 with alumina abrasive wheels

In this study,the machined surface quality of powder metallurgy nickel-based superalloy FGH96(similar to Rene88DT)and the grinding characteristics of brown alumina(BA)and microcrystalline alumina(MA)abrasive wheels were comparatively analyzed during creep feed grinding.The infuences of the grinding parameters(abrasive wheel speed,workpiece infeed speed,and depth of cut)on the grinding force,grinding temperature,surface roughness,surface morphology,tool wear,and grinding ratio were analyzed comprehensively.The experimental results showed that there was no significant difference in terms of the machined surface quality and grinding characteristics of FGH96 during grinding with the two types of abrasive wheels.This was mainly because the grinding advantages of the MA wheel were weakened for the difficult-to-cut FGH96 material.Moreover,both the BA and MA abrasive wheeIs exhibited severe tool wear in the form of wheel clogging and workpiece material adhesion.Finally,an analytical model for prediction of the grinding ratio was established by combining the tool wear volume,grinding force,and grinding length.The acceptable errors between the predicted and experimental grinding ratios(ranging from 0.6 to 1.8)were 7.56%and 6.31%for the BA and MA abrasive wheels,respectively.This model can be used to evaluate quantitatively the grinding performance of an alumina abrasive wheel,and is therefore helpful for optimizing the grinding parameters in the creep feed grinding process.

溶解润湿动力学的物理力学

溶解润湿涉及润湿、扩散及对流多个复杂的物理过程.本文采用物理力学方法研究了溶解润湿的动态过程,分析了溶质粒子进入液体内部对于液滴铺展、溶剂结构以及液滴内部流场造成的影响,结合理论得到了溶解润湿过程中的标度律.研究结果表明在液滴铺展前期界面张力驱动占主导,标度关系满足Tanner律.随着溶解的进行,溶质粒子进入液滴内部一方面造成溶剂分子结构的变化,另一方面浓度梯度的存在加快了液滴的铺展速度并改变了液滴内部的流场,且液滴内部流场中有无对流对于液滴铺展标度律会产生显著的影响.因此,溶解润湿对于液滴的内部结构、流场及铺展过程都会产生重要的影响,其研究对于理解、控制和优化涉及溶解润湿的实际问题具有十分重要的意义.

Fretting wear behaviour of machined layer of nickel-based superalloy produced by creep-feed profile grinding

Fretting wear has an adverse impact on the fatigue life of turbine blade roots.The current work is to comparatively investigate the fretting wear behaviour of the nickel-based superalloy surfaces produced by polishing and creep-feed profile grinding,respectively,in terms of surface/subsurface fretting damage,the friction coefficient,wear volume and wear rate.Experimental results show that the granulated tribolayer aggravates the workpiece wear,while the flat compacted tribolayer enhances the wear resistance ability of workpiece,irrespective of whether the workpiece is processed by polishing or grinding.However,the wear behaviors of tribolayers are different.For the polished surface,when the normal load exceeds 100 N,the main defects are crack,rupture,delamination and peeling of workpiece materials;the wear mechanism changes from severe oxidative wear to fatigue wear and abrasive wear when the loads increase from 50 to 180 N.As for the ground surface,the main wear mechanism is abrasive wear.Particularly,the ground surface possesses better wear-resistant ability than the polished surface because the former has the lower values in coefficient friction(0.23),wear volume(0.06×10^(6)μm^(3))and wear rate(0.25×10^(-16)Pa^(-1)).Finally,an illustration is given to characterize the evolution of wear debris on such nickel-based superalloy on the ground surface.

Advances in anti-tumor effects and mechanisms of Pulsatilla Chinensis saponins and its monomers

As a traditional Chinese herbal medicine, Pulsatilla Chinensis(P. Chinensis) is widely used in the clinical practice of traditional Chinese medicine(TCM). Recently, medical research has found that the natural product P. Chinensis saponins and their monomeric compounds extracted from P. Chinensis have a variety of biological activities, especially the triterpenoid saponins, which have significant and broad-spectrum anti-tumor effects. Moreover, its anti-tumor molecular mechanisms include inhibition of the growth and proliferation of tumor cells, repression of the migration, invasion, and metastasis, prevention of tumor cell cycle, regulation of cancer cell energy metabolism, anti-tumor angiogenesis, induction of cancer cell differentiation, apoptosis and autophagy, reversing cancer cell resistance, regulation a variety of related signaling pathways, and improvement of the inflammatory microenvironment of tumor cells. In the present work, we reviewed the related anticancer mechanisms of P. Chinensis saponins and their monomers in different tumors, aiming to provide a theoretical basis for the development and clinical application of new anti-tumor drugs of P. Chinensis saponins and their monomeric compounds.

Single-atom sites on perovskite chips for record-high sensitivity and quantification in SERS

Surface enhanced Raman scattering(SERS)is a rapid and nondestructive technique that is capable of detecting and identifying chemical or biological compounds.Sensitive SERS quantification is vital for practical applications,particularly for portable detection of biomolecules such as amino acids and nucleotides.However,few approaches can achieve sensitive and quantitative Raman detection of these most fundamental components in biology.Herein,a noblemetal-free single-atom site on a chip strategy was applied to modify single tungsten atom oxide on a lead halide perovskite,which provides sensitive SERS quantification for various analytes,including rhodamine,tyrosine and cytosine.The single-atom site on a chip can enable quantitative linear SERS responses of rhodamine(10^(−6)-1 mmol L^(−1)),tyrosine(0.06-1 mmol L^(−1))and cytosine(0.2-45 mmol L^(−1)),respectively,which all achieve record-high enhancement factors among plasmonic-free semiconductors.The experimental test and theoretical simulation both reveal that the enhanced mechanism can be ascribed to the controllable single-atom site,which can not only trap photoinduced electrons from the perovskite substrate but also enhance the highly efficient and quantitative charge transfer to analytes.Furthermore,the label-free strategy of single-atom sites on a chip can be applied in a portable Raman platform to obtain a sensitivity similar to that on a benchtop instrument,which can be readily extended to various biomolecules for low-cost,widely demanded and more precise point-of-care testing or in-vitro detection.