A Survey on Blockchain-Based Federated Learning:Categorization,Application and Analysis

Federated Learning(FL),as an emergent paradigm in privacy-preserving machine learning,has garnered significant interest from scholars and engineers across both academic and industrial spheres.Despite its innovative approach to model training across distributed networks,FL has its vulnerabilities;the centralized server-client architecture introduces risks of single-point failures.Moreover,the integrity of the global model—a cornerstone of FL—is susceptible to compromise through poisoning attacks by malicious actors.Such attacks and the potential for privacy leakage via inference starkly undermine FL’s foundational privacy and security goals.For these reasons,some participants unwilling use their private data to train a model,which is a bottleneck in the development and industrialization of federated learning.Blockchain technology,characterized by its decentralized ledger system,offers a compelling solution to these issues.It inherently prevents single-point failures and,through its incentive mechanisms,motivates participants to contribute computing power.Thus,blockchain-based FL(BCFL)emerges as a natural progression to address FL’s challenges.This study begins with concise introductions to federated learning and blockchain technologies,followed by a formal analysis of the specific problems that FL encounters.It discusses the challenges of combining the two technologies and presents an overview of the latest cryptographic solutions that prevent privacy leakage during communication and incentives in BCFL.In addition,this research examines the use of BCFL in various fields,such as the Internet of Things and the Internet of Vehicles.Finally,it assesses the effectiveness of these solutions.

Yinhuang granule alleviates carbon tetrachloride-induced liver fibrosis in mice and its mechanism

BACKGROUND Liver fibrosis is a formidable global medical challenge,with no effective clinical treatment currently available.Yinhuang granule(YHG)is a proprietary Chinese medicine comprising Scutellariae Radix and Lonicerae Japonicae Flos.It is frequently used for upper respiratory tract infections,pharyngitis,as well as acute and chronic tonsillitis.AIM To investigate the potential of YHG in alleviating carbon tetrachloride(CCl4)-induced liver fibrosis in mice.METHODS To induce a hepatic fibrosis model in mice,this study involved intraperitoneal injections of 2 mL/kg of CCl4 twice a week for 4 wk.Meanwhile,liver fibrosis mice in the low dose of YHG(0.4 g/kg)and high dose of YHG(0.8 g/kg)groups were orally administered YHG once a day for 4 wk.Serum alanine/aspartate aminotransferase(ALT/AST)activity and liver hydroxyproline content were detected.Sirius red and Masson's trichrome staining assay were conducted.Realtime polymerase chain reaction,western-blot and enzyme-linked immunosorbent assay were conducted.Liver glutathione content,superoxide dismutase activity level,reactive oxygen species and protein carbonylation amount were detected.RESULTS The administration of YHG ameliorated hepatocellular injury in CCl4-treated mice,as reflected by decreased serum ALT/AST activity and improved liver histological evaluation.YHG also attenuated liver fibrosis,evident through reduced liver hydroxyproline content,improvements in Sirius red and Masson's trichrome staining,and lowered serum hyaluronic acid levels.Furthermore,YHG hindered the activation of hepatic stellate cells(HSCs)and ameliorated oxidative stress injury and inflammation in liver from CCl4-treated mice.YHG prompted the nuclear accumulation of nuclear factor erythroid 2-related factor 2(Nrf2)and upregulated the expression of Nrf2-dependent downstream antioxidant genes.In addition,YHG promoted mitochondrial biogenesis in liver from CCl4-treated mice,as demonstrated by increased liver adenosine triphosphate content,mitochondrial DNA levels,and the expression of peroxisome proliferator-activated receptor gamma coactivator 1 alpha and nuclear respiratory factor 1.CONCLUSION YHG effectively attenuates CCl4-induced liver fibrosis in mice by inhibiting the activation of HSCs,reducing inflammation,alleviating liver oxidative stress damage through Nrf2 activation,and promoting liver mitochondrial biogenesis.

固-液界面接触角测定实验的课程思政设计

固液界面接触角的测定是一个重要的物理化学实验,本案例结合特殊润湿性材料可处理含油废水这一科研进展,将其改进为一个融入课程思政元素的综合创新实验,不仅能提升学生的学习兴趣,还能引导学生学会理论联系实际,利用所学专业知识来保护自然、治理环境,培养学生的社会责任感和专业自豪感,有助于达成创新型人才培养目标。

Overexpression of Sirt6 ameliorates sleep deprivation induced-cognitive impairment by modulating glutamatergic neuron function

Sleep benefits the restoration of energy metabolism and thereby suppo rts neuronal plasticity and cognitive behaviors.Sirt6 is a NAD+-dependent protein deacetylase that has been recognized as an essential regulator of energy metabolism because it modulates various transcriptional regulators and metabolic enzymes.The aim of this study was to investigate the influence of Sirt6 on cerebral function after chronic sleep deprivation(CSD).We assigned C57BL/6J mice to control or two CSD groups and subjected them to AAV2/9-CMV-EGFP or AAV2/9-CMV-Sirt6-EGFP infection in the prelimbic cortex(PrL).We then assessed cerebral functional connectivity(FC) using resting-state functional MRI,neuron/astrocyte metabolism using a metabolic kinetics analysis;dendritic spine densities using sparse-labeling;and miniature excitato ry postsynaptic currents(mEPSCs) and action potential(AP) firing rates using whole-cell patchclamp recordings.In addition,we evaluated cognition via a comprehensive set of behavioral tests.Compared with controls,Sirt6 was significantly decreased(P<0.05) in the PrL after CSD,accompanied by cognitive deficits and decreased FC between the PrL and accumbens nucleus,piriform cortex,motor co rtex,somatosensory co rtex,olfactory tubercle,insular cortex,and cerebellum.Sirt6 ove rexpression reve rsed CSD-induced cognitive impairment and reduced FC.Our analysis of metabolic kinetics using [1-13C] glucose and [2-13C] acetate showed that CSD reduced neuronal Glu4and GABA2synthesis,which could be fully restored via forced Sirt6 expression.Furthermore,Sirt6 ove rexpression reversed CSD-induced decreases in AP firing rates as well as the frequency and amplitude of mEPSCs in PrL pyramidal neurons.These data indicate that Sirt6 can improve cognitive impairment after CSD by regulating the PrL-associated FC network,neuronal glucose metabolism,and glutamatergic neurotransmission.Thus,Sirt6 activation may have potential as a novel strategy for treating sleep disorder-related diseases.

Photothermal‐boosted polaron transport in Fe_(2)O_(3)photoanodes for efficient photoelectrochemical water splitting

Introduction of the photothermal effect into transition-metal oxide photoanodes has been proven to be an effective method to improve the photoelectrochemical(PEC)water-splitting performance.However,the precise role of the photothermal effect on the PEC performance of photoanodes is still not well understood.Herein,spinel-structured ZnFe_(2)O_(4)nanoparticles are deposited on the surface of hematite(Fe_(2)O_(3)),and the ZnFe_(2)O_(4)/Fe_(2)O_(3)photoanode achieves a high photocurrent density of 3.17 mA cm^(-2)at 1.23 V versus a reversible hydrogen electrode(VRHE)due to the photothermal effect of ZnFe_(2)O_(4).Considering that the hopping of electron small polarons induced by oxygen vacancies is thermally activated,we clarify that the main reason for the enhanced PEC performance via the photothermal effect is the promoted mobility of electron small polarons that are bound to positively charged oxygen vacancies.Under the synergistic effect of oxygen vacancies and the photothermal effect,the electron conductivity and PEC performance are significantly improved,which provide fundamental insights into the impact of the photothermal effect on the PEC performance of small polaron-type semiconductor photoanodes.

Uncovering the solid-phase conversion mechanism via a new range of organosulfur polymer composite cathodes for lithium-sulfur batteries

The sulfur cathodes operating via solid phase conversion of sulfur have natural advantages in suppressing polysulfide dissolution and lowering the electrolyte dosage,and thus realizing significant improvements in both cycle life and energy density.To realize an ideal solid-phase conversion of sulfur,a deep understanding of the regulation path of reaction mechanism and a corresponding intentional material and/or cathode design are highly essential.Herein,via covalently fixing of sulfur onto the triallyl isocyanurate,a series of S-triallyl isocyanurate organosulfur polymer composites(STIs) are developed.Relationship between the structure and the electrochemical conversion behavior of STIs is systematically investigated.It is found that the structure of STIs varies with the synthetic temperature,and correspondingly the electrochemical redox of sulfur can be controlled from conventional "solid-liquid-solid" conversion to the "solid-solid" one.Among the STI series,the STI-5 composite realizes an ideal solid-phase conversion and demonstrates great potential for building a Li-S battery with high-energy density and long-cyclelife:it realizes stable cycling over 1000 cycles in carbonate electrolyte,with a degradation rate of0.053% per cycle;the corresponding pouch cell shows almost no capacity decay for 125 cycles under the conditions of high sulfur loading(4.5 mg cm^(-2)) and lean electrolyte(8 μL mg_s^(-1)).In addition,the tailoring strategy of STI can also apply to other precursors with allyl functional groups to develop new organosulfur polymers for "solid-solid" sulfur cathodes.The vulcanized triallyl phosphate(STP) and triallylamine(STA) both show great lithium storage potential.This strategy successfully develops a new family of organosulfur polymers as cathodes for Li-S batteries via solid-phase conversion of sulfur,and brings insights to the mechanism study in Li-S batteries.

Genipin relieves diabetic retinopathy by down-regulation of advanced glycation end products via the mitochondrial metabolism related signaling pathway

BACKGROUND Glycation is an important step in aging and oxidative stress,which can lead to endothelial dysfunction and cause severe damage to the eyes or kidneys of diabetics.Inhibition of the formation of advanced glycation end products(AGEs)and their cell toxicity can be a useful therapeutic strategy in the prevention of diabetic retinopathy(DR).Gardenia jasminoides Ellis(GJE)fruit is a selective inhibitor of AGEs.Genipin is an active compound of GJE fruit,which can be employed to treat diabetes.AIM To confirm the effect of genipin,a vital component of GJE fruit,in preventing human retinal microvascular endothelial cells(hRMECs)from AGEs damage in DR,to investigate the effect of genipin in the down-regulation of AGEs expression,and to explore the role of the CHGA/UCP2/glucose transporter 1(GLUT1)signal pathway in this process.METHODS In vitro,cell viability was tested to determine the effects of different doses of glucose and genipin in hRMECs.Cell Counting Kit-8(CCK-8),colony formation assay,flow cytometry,immunofluorescence,wound healing assay,transwell assay,and tube-forming assay were used to detect the effect of genipin on hRMECs cultured in high glucose conditions.In vivo,streptozotocin(STZ)induced mice were used,and genipin was administered by intraocular injection(IOI).To explore the effect and mechanism of genipin in diabetic-induced retinal dysfunction,reactive oxygen species(ROS),mitochondrial membrane potential(MMP),and 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-d-glucose(2-NBDG)assays were performed to explore energy metabolism and oxidative stress damage in high glucose-induced hRMECs and STZ mouse retinas.Immunofluorescence and Western blot were used to investigate the expression of inflammatory cytokines[vascular endothelial growth factor(VEGF),SCG3,tumor necrosis factor-alpha(TNF-α),interleukin(IL)-1β,IL-18,and nucleotide-binding domain,leucine-rich-containing family,pyrin domain-containing 3(NLRP3)].The protein expression of the receptor of AGEs(RAGE)and the mitochondria-related signal molecules CHGA,GLUT1,and UCP2 in high glucose-induced hRMECs and STZ mouse retinas were measured and compared with the genipin-treated group.RESULTS The results of CCK-8 and colony formation assay showed that genipin promoted cell viability in high glucose(30 mmol/L D-Glucose)-induced hRMECs,especially at a 0.4μmol/L dose for 7 d.Flow cytometry results showed that high glucose can increase apoptosis rate by 30%,and genipin alleviated cell apoptosis in AGEs-induced hRMECs.A high glucose environment promoted ATP,ROS,MMP,and 2-NBDG levels,while genipin inhibited these phenotypic abnormalities in AGEs-induced hRMECs.Furthermore,genipin remarkably reduced the levels of the pro-inflammatory cytokines TNF-α,IL-1β,IL-18,and NLRP3 and impeded the expression of VEGF and SCG3 in AGEs-damaged hRMECs.These results showed that genipin can reverse high glucose induced damage with regard to cell proliferation and apoptosis in vitro,while reducing energy metabolism,oxidative stress,and inflammatory injury caused by high glucose.In addition,ROS levels and glucose uptake levels were higher in the retina from the untreated eye than in the genipin-treated eye of STZ mice.The expression of inflammatory cytokines and pathway protein in the untreated eye compared with the genipin-treated eye was significantly increased,as measured by Western blot.These results showed that IOI of genipin reduced the expression of CHGA,UCP2,and GLUT1,maintained the retinal structure,and decreased ROS,glucose uptake,and inflammation levels in vivo.In addition,we found that SCG3 expression might have a higher sensitivity in DR than VEGF as a diagnostic marker at the protein level.CONCLUSION Our study suggested that genipin ameliorates AGEs-induced hRMECs proliferation,apoptosis,energy metabolism,oxidative stress,and inflammatory injury,partially via the CHGA/UCP2/GLUT1 pathway.Control of advanced glycation by IOI of genipin may represent a strategy to prevent severe retinopathy and vision loss.

超疏水表面的制备及其在含油废水处理中的应用——一个物理化学综合创新实验

以较前沿的科研成果为基础设计了一个物理化学综合创新实验。通过该实验,学生不仅可以了解油污染水环境问题,加深对润湿性一般理论的理解,还可以掌握超疏水材料的制备、接触角表征以及超疏水/超亲油材料对含油废水进行处理的操作和方法。实验融入了较多的课程思政元素,通过引导学生利用课堂学习的表面化学理论知识解决含油废水处理问题,培养学生的社会责任感、专业自豪感、严谨的科学思维和创新能力。

Rumen microbial-driven metabolite from grazing lambs potentially regulates body fatty acid metabolism by lipid-related genes in liver

Background Lipid metabolism differs significantly between grazing and stall-feeding lambs,affecting the quality of livestock products.As two critical organs of lipid metabolism,the differences between feeding patterns on rumen and liver metabolism remain unclear.In this study,16S rRNA,metagenomics,transcriptomics,and untargeted metabolomics were utilized to investigate the key rumen microorganisms and metabolites,as well as liver genes and metabolites associated with fatty acid metabolism under indoor feeding(F)and grazing(G).Results Compared with grazing,indoor feeding increased ruminal propionate content.Using metagenome sequencing in combination with 16S rRNA amplicon sequencing,the results showed that the abundance of propionate-producing Succiniclasticum and hydrogenating bacteria Tenericutes was enriched in the F group.For rumen metabolism,grazing caused up-regulation of EPA,DHA and oleic acid and down-regulation of decanoic acid,as well as,screening for 2-ketobutyric acid as a vital differential metabolite,which was enriched in the propionate metabolism pathway.In the liver,indoor feeding increased 3-hydroxypropanoate and citric acid content,causing changes in propionate metabolism and citrate cycle,while decreasing the ETA content.Then,the liver transcriptome revealed that 11 lipid-related genes were differentially expressed in the two feeding patterns.Correlation analysis showed that the expression of CYP4A6,FADS1,FADS2,ALDH6A1 and CYP2C23 was significantly associated with the propionate metabolism process,suggesting that propionate metabolism may be an important factor mediating the hepatic lipid metabolism.Besides,the unsaturated fatty acids in muscle,rumen and liver also had a close correlation.Conclusions Overall,our data demonstrated that rumen microbial-driven metabolite from grazing lambs potentially regulates multiple hepatic lipid-related genes,ultimately affecting body fatty acid metabolism.

Gravity anomalies determined from mean sea surface model data over the Gulf of Mexico

With the improvements in the density and quality of satellite altimetry data,a high-precision and high-resolution mean sea surface model containing abundant information regarding a marine gravity field can be calculated from long-time series multi-satellite altimeter data.Therefore,in this study,a method was proposed for determining marine gravity anomalies from a mean sea surface model.Taking the Gulf of Mexico(15°–32°N,80°–100°W)as the study area and using a removal-recovery method,the residual gridded deflections of the vertical(DOVs)are calculated by combining the mean sea surface,mean dynamic topography,and XGM2019e_2159 geoid,and then using the inverse Vening-Meinesz method to determine the residual marine gravity anomalies from the residual gridded DOVs.Finally,residual gravity anomalies are added to the XGM2019e_2159 gravity anomalies to derive marine gravity anomaly models.In this study,the marine gravity anomalies were estimated with mean sea surface models CNES_CLS15MSS,DTU21MSS,and SDUST2020MSS and the mean dynamic topography models CNES_CLS18MDT and DTU22MDT.The accuracy of the marine gravity anomalies derived by the mean sea surface model was assessed based on ship-borne gravity data.The results show that the difference between the gravity anomalies derived by DTU21MSS and CNES_CLS18MDT and those of the ship-borne gravity data is optimal.With an increase in the distance from the coast,the difference between the gravity anomalies derived by mean sea surface models and ship-borne gravity data gradually decreases.The accuracy of the difference between the gravity anomalies derived by mean sea surface models and those from ship-borne gravity data are optimal at a depth of 3–4 km.The accuracy of the gravity anomalies derived by the mean sea surface model is high.

Cross-linked polyelectrolyte reinforced SnO_(2)electron transport layer for robust flexible perovskite solar cells

SnO_(2)electron transport layer(ETL)is a vital component in perovskite solar cells(PSCs),due to its excellent photoelectric properties and facile fabrication process.In this study,we synthesized a water-soluble and adhesive polyelectrolyte with ethanolamine(EA)and poly-acrylic acid(PAA).The linear PAA was crosslinked by EA,forming a 3D network that stabilized the SnO_(2)nanoparticle dispersion.An organic–inorganic hybrid ETL is developed by introducing the cross-linked PAA-EA into SnO_(2)ETL,which prevents nano particle agglomeration and facilitates uniform SnO_(2)film formation with fewer defects.Additionally,the PAA-EA-modified SnO_(2)facilitated a uniform and compact perovskite film,enhancing the interface contact and carrier transport.Consequently,the PAA-EA-modified PSCs exhibited excellent PCE of 24.34%and 22.88%with high reproducibility for areas of 0.045 and 1.00 cm~2,respectively.Notably,owing to structure reinforce effect of PAA-EA in SnO_(2)ETL,flexible device demonstrated an impressive PCE of 23.34%while maintaining 90.1%of the initial PCE after 10,000 bending cycles with a bending radius of 5 mm.This successful approach of polyelectrolyte reinforced hybrid organic–inorganic ETL displays great potential for flexible,large-area PSCs application.

State of art on the mechanisms of laparoscopic sleeve gastrectomy in treating type 2 diabetes mellitus

Obesity and type-2 diabetes mellitus(T2DM)are metabolic disorders.Obesity increases the risk of T2DM,and as obesity is becoming increasingly common,more individuals suffer from T2DM,which poses a considerable burden on health systems.Traditionally,pharmaceutical therapy together with lifestyle changes is used to treat obesity and T2DM to decrease the incidence of comorbidities and allcause mortality and to increase life expectancy.Bariatric surgery is increasingly replacing other forms of treatment of morbid obesity,especially in patients with refractory obesity,owing to its many benefits including good long-term outcomes and almost no weight regain.The bariatric surgery options have markedly changed recently,and laparoscopic sleeve gastrectomy(LSG)is gradually gaining popularity.LSG has become an effective and safe treatment for type-2 diabetes and morbid obesity,with a high cost-benefit ratio.Here,we review the mechanism associated with LSG treatment of T2DM,and we discuss clinical studies and animal experiments with regard to gastrointestinal hormones,gut microbiota,bile acids,and adipokines to clarify current treatment modalities for patients with obesity and T2DM.

经皮穴位电刺激治疗术后疼痛的最佳证据总结

目的 总结经皮穴位电刺激及其相关技术治疗术后疼痛的证据,为临床实践提供依据。方法 系统检索BMJ Best Practice、JBI、UpToDate、GIN、NICE、SIGN、RNAO、医脉通、梅斯医学网站、国家中医药管理局、Epistemonikos、Cochrane Library、PubMed、Embase、Web of Science、CBM、CNKI、万方、维普和中华医学期刊全文数据库中关于经皮穴位电刺激及其相关技术治疗术后疼痛的证据,由经过循证培训的小组成员对文献质量进行评价,对证据进行提取、汇总并分级。结果 共纳入13篇文献,包括1篇指南,3篇系统评价和9篇随机对照试验。从治疗适应证、治疗获益、刺激参数、干预时机、穴位选择和操作者资质6个方面汇总了24条证据。结论 经皮穴位电刺激治疗可以缓解术后疼痛,不同的刺激参数、干预时机及穴位选择会影响疗效,建议临床应用时结合各医院科室的实际情况,有针对性地选择证据,以提升其有效性。

Analysis of“Teaching”and“Learning”in Interdisciplinary Learning

After the release of the new curriculum plan,interdisciplinary learning has emerged as a pivotal aspect of curriculum reform in compulsory education.This shift has necessitated a corresponding reform in the teaching and learning methods of fundamental education courses.The implementation of interdisciplinary learning has consequently become a pressing challenge in educational practice.To successfully execute interdisciplinary learning,several key preparations are imperative.Firstly,educators must recognize the significance of interdisciplinary teaching.Secondly,they should clearly understand that the essence of interdisciplinary learning lies in the enhancement of students’core qualities.Thirdly,teachers need to prioritize their professional development,cultivating a robust understanding of interdisciplinary knowledge and bolstering their proficiency in interdisciplinary teaching.Lastly,students themselves must foster a diverse range of interests,cultivate high-level thinking abilities,and develop effective learning habits across multiple fields.

基于数据非依赖性采集定量蛋白质组学分析的原发性干燥综合征潜在唾液生物标志物研究

目的唾液腺是原发性干燥综合征(pSS)的主要靶器官,因此唾液被认为是腺体病理生理学和疾病状态的镜子。本研究旨在说明pSS患者的唾液蛋白质组学特征,并鉴定可能辅助诊断的潜在生物标志物。方法发现集包含49个样本[24个来自pSS,25个来自年龄和性别匹配的健康对照(HCs)],验证集包括25个样本(12个来自pSS,13个来自HCs)。36例pSS患者和38例健康对照者以2:1的比例集中随机分配至Discovery组或验证组。在2D LC-HRMS/MS平台上使用数据非依赖性采集(DIA)策略分析来自pSS患者和健康对照组的未刺激性全唾液样本,以揭示差异蛋白。根据基因本体(GO)分析和国际药学文摘(IPA)分析的蛋白质注释,使用DIA分析验证了关键蛋白质。随机森林用于建立SS的预测模型。结果共发现1,963个蛋白,其中136个蛋白在pSS患者中表现出差异性。生物信息学研究表明这些蛋白质主要与免疫功能、新陈代谢和炎症有关。一组19个蛋白质生物标志物通过基于P值和随机森林的排序顺序进行鉴定,并验证为具有特殊曲线下面积(AUC)值(发现集:0.817;验证集:0.882)的潜在生物标志物,可用于鉴别pSS患者和健康对照人群。结论新发现的候选蛋白组合可能有助于pSS的诊断。唾液蛋白质组学分析是一种很有前途的无创方法,可用于对pSS患者进行预后评估以及早期和精确治疗。DIA具备最佳的时间效率和数据可靠性,可望成为未来唾液蛋白质组研究的合适选择。

大量程浊度测量的散射角实验研究

浊度对于评价水体质量具有重要的意义。针对90°散射法在高浊度范围测量误差大、分辨率低的问题,提出了一种135°散射大量程浊度测量方法。由于散射相位函数与散射角密切相关,实验研究了散射角的浊度测量适应性。通过多项式拟合阶次分析发现,在100 NTU~2000 NTU范围内单一散射条件下,135°散射法具有更大的量程范围。经过实验标定,分段线性拟合的R^(2)结果分别为0.99(100 NTU~800 NTU),0.98(800 NTU~1500 NTU)和0.99(1500 NTU~2000 NTU)。实验证明,135°散射法可以扩大浊度测量范围,改善高浊度范围内测量精度。

预应力混凝土风机塔架结构安全性影响因素研究

预应力混凝土塔架较钢制塔架具有更高的抗疲劳特性及稳定性,能够满足复杂地形的建设需求。基于现场监测数据,利用混凝土塑性损伤模型对塔架结构进行全尺寸建模,通过对比监测数据与数值仿真结果,研究了预应力损失、混凝土劣化及表观缺陷等因素对塔架结构力学性能的影响规律。结果表明,预应力混凝土塔架结构安全受多种因素影响,随着结构的劣化塔架刚度逐渐软化,低阶振型对结构共振的影响较大,塔架结构损伤形式趋向于受拉破坏。

高导热相变水凝胶的制备及温度响应性

传统的相变水凝胶用于温度监测时会面临响应时间长、力学性能不佳、导电性能差、相变焓低等问题。因此,文中以黄原胶和聚乙烯醇为主要原料,利用黄原胶分子的多官能团活性和分散性,对石蜡进行乳化,结合Zn2+和纳米氧化铝的离子导电性和高导热性,制备了兼具高热焓、高导热、高导电和强力学的双网络交联黄原胶/石蜡/聚乙烯醇/硼酸/锌离子/纳米氧化铝(XPPB-Zn^(2+)-Al_(2)O_(3))相变水凝胶。扫描电镜图片显示,相变微粒均匀嵌入到水凝胶的微结构中;力学测试结果显示,双交联网络赋予相变水凝胶优异的力学性能,其拉伸强度达到(0.38±0.01) MPa;差示扫描量热分析显示,水凝胶相变焓高达(180.98±3.12) J/g。此外,相变水凝胶展现出高的导热性,其热传导系数达到(0.558±0.035)W/(m·K),电阻温度系数达到1.23%℃-1,在25~60℃范围内,显示出良好的温度循环稳定性。文中所制备的高性能相变水凝胶在温度监测领域具有良好的应用前景。

基于全生命周期的建筑加压调蓄系统碳核算方法研究

随着城市化进程加快,人口密度提高,建筑高度也在不断增长。建筑加压调蓄系统是高层建筑运行过程中不可或缺的组成部分,近年来各地区逐步推动水务企业接管建筑加压调蓄系统,但目前对建筑加压调蓄系统的碳排放核算仍缺少统一的方法。以全生命周期评价为理论基础,采用排放因子法作为计算方法,构建建筑加压调蓄系统的碳排放核算模型并选取上海市某建筑进行案例分析,最后提出了系统碳减排策略。案例分析结果表明运行维护阶段碳排放占比最大,约为62.5%,进一步说明优化水泵效率对系统碳减排的重要性,为后续的理论研究奠定了基础。

Exploring the impact of Nafion modifier on electrocatalytic CO_(2) reduction over Cu catalyst

Nafion as a universal polymer ionomer was widely applied for nanocatalysts electrode preparation.However,the effect of Nafion on electrocatalytic performance was often overlooked,especially for CO_(2)electrolysis.Herein,the key roles of Nafion for CO_(2)RR were systematically studied on Cu nanoparticles(NPs)electrocatalyst.We found that Nafion modifier not only inhibit hydrogen evolution reaction(HER)by decreasing the accessibility of H_(2)O from electrolyte to Cu NPs,and increase the CO_(2)concentration at electrocatalyst interface for enhancing the CO_(2)mass transfer process,but also activate CO_(2)molecule by Lewis acid-base interaction between Nafion and CO_(2)to accelerate the formation of^(*)CO,which favor of C–C coupling for boosting C_(2)product generation.Owing to these features,the HER selectivity was suppressed from 40.6%to 16.8%on optimal Cu@Nafion electrode at-1.2 V versus reversible hydrogen electrode(RHE),and as high as 73.5%faradaic efficiencies(FEs)of C_(2)products were achieved at the same applied potential,which was 2.6 times higher than that on bare Cu electrode(~28.3%).In addition,Nafion also contributed to the long-term stability by hinder Cu NPs morphology reconstruction.Thus,this work provides insights into the impact of Nafion on electrocatalytic CO_(2)RR performance.