政府回应、政策收益与公众政策评价:基于清洁取暖改造执行的联合实验研究

在长期政策实施过程中调整政府行为与优化政策设计,以提升公众对政策的评价是国家治理效能的体现。本文从政府回应和政策收益两个层面探索政策实施中的公众政策评价的形成与影响机制。基于清洁取暖改造政策情境的联合实验设计,本文对北方某一地级市的农村居民开展实地入户问卷调查。研究结果证实了政府回应可以显著提升公众政策评价,个体政策收益的利他、互惠、利己维度在促进公众政策评价的正向影响方面呈现由低到高的谱系。在影响机制方面,政府回应增强了政策利他收益对公众政策评价的影响,呈现出与政策收益之间的互补效应;政策执行时长、信息获取、政府信任等因素均会调节政府回应和政策收益对公众政策评价的影响。政府基于动态政策评估及时识别公众政策评价,并结合评价来改善执行过程中的治理行为与方式,是促进公众满意与可持续治理的潜在路径。

随机疲劳下复合材料剩余刚度-剩余强度关联模型及寿命预测

剩余刚度和剩余强度作为描述复合材料疲劳损伤程度最常见的方法,在应用过程中都存在各自的优缺点。刚度试验成本低,但缺少明确的失效判据使得其实际工程中的应用受到限制,强度虽然存在天然的失效判据,但破坏性试验导致试验成本较高。考虑复合材料结构大多在随机交变载荷下服役,如噪声、振动等。本文通过复合材料常幅疲劳数据推导了随机疲劳下的剩余强度曲线,提出了一种随机载荷下的剩余刚度-强度关联模型,减少了试验时间和成本,并通过关联模型预测了结构随机疲劳寿命,预测值与试验值具有较好的一致性。

Exosomes derived from microglia overexpressing miR-124-3p alleviate neuronal endoplasmic reticulum stress damage after repetitive mild traumatic brain injury

We previously reported that miR-124-3p is markedly upregulated in microglia-derived exosomes following repetitive mild traumatic brain injury.However,its impact on neuronal endoplasmic reticulum stress following repetitive mild traumatic brain injury remains unclear.In this study,we first used an HT22 scratch injury model to mimic traumatic brain injury,then co-cultured the HT22 cells with BV2 microglia expressing high levels of miR-124-3p.We found that exosomes containing high levels of miR-124-3p attenuated apoptosis and endoplasmic reticulum stress.Furthermore,luciferase reporter assay analysis confirmed that miR-124-3p bound specifically to the endoplasmic reticulum stress-related protein IRE1α,while an IRE1αfunctional salvage experiment confirmed that miR-124-3p targeted IRE1αand reduced its expression,thereby inhibiting endoplasmic reticulum stress in injured neurons.Finally,we delivered microglia-derived exosomes containing miR-124-3p intranasally to a mouse model of repetitive mild traumatic brain injury and found that endoplasmic reticulum stress and apoptosis levels in hippocampal neurons were significantly reduced.These findings suggest that,after repetitive mild traumatic brain injury,miR-124-3 can be transferred from microglia-derived exosomes to injured neurons,where it exerts a neuroprotective effect by inhibiting endoplasmic reticulum stress.Therefore,microglia-derived exosomes containing miR-124-3p may represent a novel therapeutic strategy for repetitive mild traumatic brain injury.

Effect of long reaction distance on gas composition from organic-rich shale pyrolysis under high-temperature steam environment

When high-temperature steam is used as a medium to pyrolyze organic-rich shale,water steam not only acts as heat transfer but also participates in the chemical reaction of organic matter pyrolysis,thus affecting the generation law and release characteristics of gas products.In this study,based on a long-distance reaction system of organic-rich shale pyrolysis via steam injection,the effects of steam temperature and reaction distance on gas product composition are analyzed in depth and compared with other pyrolysis processes.The advantages of organic-rich shale pyrolysis via steam injection are then evaluated.The volume concentration of hydrogen in the gas product obtained via the steam injection pyrolysis of organic-rich shale is the highest,which is more than 60%.The hydrogen content increases as the reaction distance is extended;however,the rate of increase changes gradually.Increasing the reaction distance from 800 to 4000 mm increases the hydrogen content from 34.91%to 69.68%and from 63.13%to 78.61%when the steam temperature is 500°C and 555°C,respectively.However,the higher the heat injection temperature,the smaller the reaction distance required to form a high concentration hydrogen pyrolysis environment(hydrogen concentration>60%).When the steam pyrolysis temperature is increased from 500°C to 555°C,the reaction distance required to form a high concentration of hydrogen is reduced from 3800 to 800 mm.Compared with the direct retorting process,the volume concentration of hydrogen obtained from high-temperature steam pyrolysis of organic-rich shale is 8.82 and 10.72 times that of the commonly used Fushun and Kivite furnaces,respectively.The pyrolysis of organic-rich shale via steam injection is a pyrolysis process in a hydrogen-rich environment.

Noise-Tolerant ZNN-Based Data-Driven Iterative Learning Control for Discrete Nonaffine Nonlinear MIMO Repetitive Systems

Aiming at the tracking problem of a class of discrete nonaffine nonlinear multi-input multi-output(MIMO) repetitive systems subjected to separable and nonseparable disturbances, a novel data-driven iterative learning control(ILC) scheme based on the zeroing neural networks(ZNNs) is proposed. First, the equivalent dynamic linearization data model is obtained by means of dynamic linearization technology, which exists theoretically in the iteration domain. Then, the iterative extended state observer(IESO) is developed to estimate the disturbance and the coupling between systems, and the decoupled dynamic linearization model is obtained for the purpose of controller synthesis. To solve the zero-seeking tracking problem with inherent tolerance of noise,an ILC based on noise-tolerant modified ZNN is proposed. The strict assumptions imposed on the initialization conditions of each iteration in the existing ILC methods can be absolutely removed with our method. In addition, theoretical analysis indicates that the modified ZNN can converge to the exact solution of the zero-seeking tracking problem. Finally, a generalized example and an application-oriented example are presented to verify the effectiveness and superiority of the proposed process.

4种肌少症筛查工具在慢性肝病患者中应用的性能比较

目的比较shii评分、 肌少症筛查5项评分量表(Strength, Assistance with Walking, Rise from aChair, Climb Stairs and Falls , SARC-F).肌少症筛查5项评分联合小腿围量表(SARC-F and Calf Circumferen-ce, SARC-CalF)及迷你肌少症风险评估-7条目问卷(Mini Sarcopenia Risk Assessment-7 ,MSRA-7)筛查慢性肝病患者肌少症的相对准确性。方法该前瞻性研究纳人366例慢性肝病患者。应用Ishii评分.SARC-F、SARC-CalF和MSRA-7对患者进行筛查。肌少症由临床医生根据亚洲肌少症工作组(AsiaWorkingGroupforSarco-penia,AWGS)2019标准进行诊断,以此为金标准对4种筛查工具的性能进行比较。结果基于AWGS2019标准,本组慢性肝病患者的肌少症患病率为17.5%。Ishii评分、SARC-F .SARC-CalF和MSRA-7的受试者工作特征(receiver operating characteristic, ROC)曲线下面积(敏感度,特异度)分别为0.820(8594% ,78.15%)、0.528(6.25% , 99.34%) 0.642(45.31% , 83.1 1%).0.552(87.50% ,22.85%)。根据ROC曲线下面积、决策曲线以及校准曲线分析结果,Ishi评分筛查馒性肝病患者肌少症的性能优于其他3个工具(P<0.0001)。结论Ishii评分比SARC-F.SARC-CalF和MSRA-7更适合用于筛查馒性肝病患者的肌少症。护士在临床工作中可应用Ishii评分对慢性肝病患者进行肌少症筛查,早期发现肌少症风险,为进一步诊断肌少症提供依据。

2D DOA Estimation of Coherent Signals with a Separated Linear Acoustic Vector-Sensor Array

In this paper, a two-dimensional(2D) DOA estimation algorithm of coherent signals with a separated linear acoustic vector-sensor(AVS) array consisting of two sparse AVS arrays is proposed. Firstly,the partitioned spatial smoothing(PSS) technique is used to construct a block covariance matrix, so as to decorrelate the coherency of signals. Then a signal subspace can be obtained by singular value decomposition(SVD) of the covariance matrix. Using the signal subspace, two extended signal subspaces are constructed to compensate aperture loss caused by PSS.The elevation angles can be estimated by estimation of signal parameter via rotational invariance techniques(ESPRIT) algorithm. At last, the estimated elevation angles can be used to estimate automatically paired azimuth angles. Compared with some other ESPRIT algorithms, the proposed algorithm shows higher estimation accuracy, which can be proved through the simulation results.

成渝地区“六江”生态廊道规划分区及管控策略研究

科学开展规划分区是对国土空间保护、修复和合理开发利用的前提。本文以成渝地区“六江”生态廊道为例,在掌握区域生态本底的基础上,识别突出生态问题,评估生态系统服务功能,开展生态廊道分区划定与管控策略研究。研究表明:(1)研究区内主要存在水土流失、石漠化、地质灾害、林地质量不高、耕地退化、生物多样性风险加剧等突出生态问题;(2)人类活动干扰强度大,生态功能以一般区为主,占比40.94%,极重要区占比26.62%,主要分布在长江屏山段、云阳—巫山段,岷江都江堰段,沱江绵竹段及乌江沿线的高海拔地区;(3)结合“三区三线”管控要求和国土空间总体格局,划定生态保护区、生态修复区和生态合理利用区,分别占比30.50%、15.26%和54.24%,并制定分区管控策略。

The relationship between compartment models and their stochastic counterparts:A comparative study with examples of the COVID-19 epidemic modeling

Deterministic compartment models(CMs)and stochastic models,including stochastic CMs and agent-based models,are widely utilized in epidemic modeling.However,the relationship between CMs and their corresponding stochastic models is not well understood.The present study aimed to address this gap by conducting a comparative study using the susceptible,exposed,infectious,and recovered(SEIR)model and its extended CMs from the coronavirus disease 2019 modeling literature.We demonstrated the equivalence of the numerical solution of CMs using the Euler scheme and their stochastic counterparts through theoretical analysis and simulations.Based on this equivalence,we proposed an efficient model calibration method that could replicate the exact solution of CMs in the corresponding stochastic models through parameter adjustment.The advancement in calibration techniques enhanced the accuracy of stochastic modeling in capturing the dynamics of epidemics.However,it should be noted that discrete-time stochastic models cannot perfectly reproduce the exact solution of continuous-time CMs.Additionally,we proposed a new stochastic compartment and agent mixed model as an alternative to agent-based models for large-scale population simulations with a limited number of agents.This model offered a balance between computational efficiency and accuracy.The results of this research contributed to the comparison and unification of deterministic CMs and stochastic models in epidemic modeling.Furthermore,the results had implications for the development of hybrid models that integrated the strengths of both frameworks.Overall,the present study has provided valuable epidemic modeling techniques and their practical applications for understanding and controlling the spread of infectious diseases.

Twin-Capture Rydberg State Excitation Enhanced with Few-Cycle Laser Pulses

Quantum excitation is usually regarded as a transient process occurring instantaneously,leaving the underlying physics shrouded in mystery.Recent research shows that Rydberg-state excitation with ultrashort laser pulses can be investigated and manipulated with state-of-the-art few-cycle pulses.We theoretically find that the efficiency of Rydberg state excitation can be enhanced with a short laser pulse and modulated by varying the laser intensities.We also uncover new facets of the excitation dynamics,including the launching of an electron wave packet through strong-field ionization,the re-entry of the electron into the atomic potential and the crucial step where the electron makes a U-turn,resulting in twin captures into Rydberg orbitals.By tuning the laser intensity,we show that the excitation of the Rydberg state can be coherently controlled on a sub-optical-cycle timescale.Our work paves the way toward ultrafast control and coherent manipulation of Rydberg states,thus benefiting Rydberg-state-based quantum technology.

Ten-year observation of corneal densitometry and associated factors following small incision lenticule extraction

●AIM:To investigate the long-term changes of corneal densitometry(CD)and its contributing elements after small incision lenticule extraction(SMILE).●METHODS:Totally 31 eyes of 31 patients with mean spherical equivalent of-6.46±1.50 D and mean age 28.23±7.38y were enrolled.Full-scale examinations were conducted on all patients preoperatively and during followup.Visual acuity,manifest refraction,axial length,corneal thickness,corneal higher-order aberrations,and CD were evaluated.●RESULTS:All surgeries were completed successfully without complications or adverse events.Ten-year safety index was 1.17±0.20 and efficacy 1.04±0.28.CD value of 0–6 mm zones in central layer was statistically significantly lower 10y postoperatively,compared with preoperative values(0–2 mmΔ=-1.62,2–6 mmΔ=-1.24,P<0.01).There were no correlations between CD values and factors evaluated.●CONCLUSION:SMILE is a safe and efficient procedure for myopia on a long-term basis.CD values get lower 10y postoperatively,whose mechanism is to be further discussed.

Pathological diagnosis and immunohistochemical analysis of giant retrosternal goiter in the elderly: A case report

BACKGROUND Elderly giant retrosternal thyroid goiter is a rare yet significant medical condition,often presenting clinical symptoms that can be confused with other diseases,posing diagnostic and therapeutic challenges.This study aims to delve into the characteristics and potential mechanisms of this ailment through pathological diagnosis and immunohistochemical analysis,providing clinicians with more precise diagnostic and treatment strategies.A 77-year-old male,was admitted to hospital with the chief complaint of finding a goiter in the semilunar month during physical examination,accompanied by dyspnea.Locally protruding into the superior mediastinum,the adjacent structure was compressed,the trachea was compressed to the right,and the local lumen was slightly narrowed.The patient was diagnosed with giant retrosternal goiter.Considering dyspnea caused by trachea compression,our department planned to perform giant retrosternal thyroidectomy.Immunohistochemical results:Tg(+),TTF-1(+),Calcitonin(CT)(I),Ki-67(+,about 20%),CD34(-).Retrosternal goiter means that more than 50%of the volume of the thyroid gland is below the upper margin of the sternum.As retrosternal goiter disease is a relatively rare disease,once the disease is diagnosed,it should be timely surgical treatment,and the treatment is more difficult,the need for professional medical team for comprehensive treatment.CONCLUSION The imaging manifestations of giant retrosternal goiter are atypical,histomorphology and immunohistochemistry can assist in its diagnosis.This article reviews the relevant literature of giant retrosternal goiter immunohisto-chemistry and shows that giant retrosternal goiter is positive for Tg,TTF-1,and Ki-67.

Lean body mass index is a marker of advanced tumor features in patients with hepatocellular carcinoma

BACKGROUND Obesity is an independent risk factor for the development of hepatocellular carcinoma(HCC)and may influence its outcomes.However,after diagnosis of HCC,like other malignancies,the obesity paradox may exist where higher body mass index(BMI)may in fact confer a survival benefit.This is frequently observed in patients with advanced HCC and cirrhosis,who often present late with advanced tumor features and cancer related weight loss.AIM To explore the relationship between BMI and survival in patients with cirrhosis and HCC.METHODS This is a retrospective cohort study of over 2500 patients diagnosed with HCC between 2009-2019 at two United States academic medical centers.Patient and tumor characteristics were extracted manually from medical records of each institutions'cancer registries.Patients were stratified according to BMI classes:<25 kg/m^(2)(lean),25-29.9 kg/m^(2)(overweight),and>30 kg/m^(2)(obese).Patient and tumor characteristics were compared according to BMI classification.We performed an overall survival analysis using Kaplan Meier by the three BMI classes and after adjusting for Milan criteria.A multivariable Cox regression model was then used to assess known risk factors for survival in patients with cirrhosis and HCC.RESULTS A total of 2548 patients with HCC were included in the analysis of which 11.2%(n=286)were classified as noncirrhotic.The three main BMI categories:Lean(n=754),overweight(n=861),and obese(n=933)represented 29.6%,33.8%,and 36.6%of the total population overall.Within each BMI class,the non-cirrhotic patients accounted for 15%(n=100),12%(n=94),and 11%(n=92),respectively.Underweight patients with a BMI<18.5 kg/m^(2)(n=52)were included in the lean cohort.Of the obese cohort,42%(n=396)had a BMI≥35 kg/m^(2).Out of 2262 patients with cirrhosis and HCC,654(29%)were lean,767(34%)were overweight,and 841(37%)were obese.The three BMI classes did not differ by age,MELD,or Child-Pugh class.Chronic hepatitis C was the dominant etiology in lean compared to the overweight and obese patients(71%,62%,49%,P<0.001).Lean patients had significantly larger tumors compared to the other two BMI classes(5.1 vs 4.2 vs 4.2 cm,P<0.001),were more likely outside Milan(56%vs 48%vs 47%,P<0.001),and less likely to undergo transplantation(9%vs 18%vs 18%,P<0.001).While both tumor size(P<0.0001)and elevated alpha fetoprotein(P<0.0001)were associated with worse survival by regression analysis,lean BMI was not(P=0.36).CONCLUSION Lean patients with cirrhosis and HCC present with larger tumors and are more often outside Milan criteria,reflecting cancer related cachexia from delayed diagnosis.Access to care for hepatitis C virus therapy and liver transplantation confer a survival benefit,but not overweight or obese BMI classifications.

Effects of ulinastatin combined with dexmedetomidine on cognitive dysfunction and emergence agitation in elderly patients who underwent total hip arthroplasty

BACKGROUND With the continuous growth of the modern elderly population,the risk of fracture increases.Hip fracture is a common type of fracture in older people.Total hip arthroplasty(THA)has significant advantages in relieving chronic pain and promoting the recovery of hip joint function.AIM To investigate the effect of ulinastatin combined with dexmedetomidine(Dex)on the incidences of postoperative cognitive dysfunction(POCD)and emergence agitation in elderly patients who underwent THA.METHODS A total of 397 patients who underwent THA from February 2019 to August 2022.We conducted a three-year retrospective cohort study in Shaanxi Provincial People’s Hospital.Comprehensive demographic data were obtained from the electronic medical record system.We collected preoperative,intraoperative,and postoperative data.One hundred twenty-nine patients who were administered Dex during the operation were included in the Dex group.One hundred fifty patients who were intravenously injected with ulinastatin 15 min before anesthesia induction were included in the ulinastatin group.One hundred eighteen patients who were administered ulinastatin combined with Dex during the operation were included in the Dex+ulinastatin group.The patients’perioperative conditions,hemodynamic indexes,postoperative Mini-Mental State Examination(MMSE)scores,Ramsay score,incidence of POCD,and serum inflammatory cytokines were evaluated.RESULTS There was a significant difference in the 24 h visual analogue scale score among the three groups,and the score in the Dex+ulinastatin group was the lowest(P<0.05).Compared with the Dex and ulinastatin group,the MMSE scores of the Dex+ulinastatin group were significantly increased at 1 and 7 d after the operation(all P<0.05).Compared with those in the Dex and ulinastatin groups,incidence of POCD,levels of serum inflammatory cytokines in the Dex+ulinastatin group were significantly decreased at 1 and 7 d after the operation(all P<0.05).The observer’s assessment of the alertness/sedation score and Ramsay score of the Dex+ulinastatin group were significantly different from those of the Dex and ulinastatin groups on the first day after the operation(all P<0.05).CONCLUSION Ulinastatin combined with Dex can prevent the occurrence of POCD and emergence agitation in elderly patients undergoing THA.

Exploration of Human Resource Management in Enterprise Business Management

Human resource management is an integral part of enterprise operation and management,contributing to the avoidance of financial risks,alleviation of performance problems,promotion of organizational development,enhancement of operational efficiency,and fostering sustainable enterprise development.Enterprise management should prioritize attention to human resource management by establishing an independent human resource management department and strategically planning human resource management tasks.This involves building an information management platform,developing a professional human resource management model to mitigate market risks,actively recruiting human resource management talents to form a competent team,and enhancing the human resource management and supervision system.These measures are essential for comprehensively improving the level of enterprise operation and management.

中国故事翻译研究(2013~2023)知识图谱分析

利用可视化知识图谱软件CiteSpace,对“CNKI中国学术期刊(网络版)”数据库检索的491篇中国故事翻译研究文献进行可视化分析,考察该领域总体特征、研究热点与趋势。结果显示:(1)根据整体发文数量,中国故事翻译研究可分为初步繁荣期、学术累积期与平稳发展期;(2)研究热点涉及翻译策略、典籍翻译、文化外译、文学外译、译介,前沿话题包括中国特色、出版与文化自信。后续研究应注意多学科互动,使用多元互证方法,扩展研究对象,加强受众研究,以利中国故事翻译研究健康发展。

Optimal Cut-off Point of Waist to Height Ratio in Beijing and Its Association with Clusters of Metabolic Risk Factors

A host of studies found waist-to-height ratio(WHtR)having higher diagnostic value than other abdominal obesity anthropometric indicators for metabolic disorders.But the cut-off points are still not consistent.This study was aimed to explore the optimal cut-off point of WHtR in Chinese population and identify the association between WHtR and cluster of metabolic risk factors.In total,13379 Han adults(7553 men and 5726 women)from over 40 institutions who took physical examination in Xuanwu Hospital of Capital Medical University between January 2014 and January 2015 were involved in this cross-sectional study.Subjects with two or more components of metabolic syndrome(MetS)were considered to have multiple risk factors.Optimal cut-off points of WHtR for cluster of metabolic risk factors were analyzed by receiver operating characteristic(ROC)curve analysis.The optimal cut-off points of WHtR were 0.51 for men and 0.49 for women.People with elevated WHtR had higher levels of metabolic risk factors.And the prevalence of individual and clusters of 5 risk factors were all higher among WHtR-defined abdominal obesity people than in normal subjects.The optimal cut-off points of WHtR were 0.51 for men and 0.49 for women.In conclusion,people with elevated WHtR.are susceptible to cluster of metabolic risk factors.

小细胞肺癌的分子分型及其治疗策略的研究进展

小细胞肺癌(small cell lung cancer,SCLC)是一种具有极强增殖和侵袭能力的恶性肿瘤,由于缺乏有效治疗手段,临床预后差。近年来,对细胞、动物模型及肿瘤组织本身的研究推动了SCLC分子亚型的提出,并发现不同分子亚型的SCLC具有独特的生物学和临床特征及潜在的特异性治疗靶点,这将有助于为SCLC患者制定更精准的治疗策略,以期改善预后。本文拟对目前关于SCLC的分子分型进行综述,重点关注不同分子分型的SCLC的临床特征以及治疗策略,并提出未来SCLC治疗的合理建议。

基于代谢组学探究豨芍方治疗神经性病理性疼痛的镇痛机制

目的:通过代谢组学和网络药理学探究豨芍方(Xi Shao Formula,XSF)治疗神经性疼痛(neuropathic pain,NP)的机制。方法:建立NP的坐骨神经慢性压缩损伤(chronic compression injury,CCI)模型。造模后,分别给予生理盐水、XSF或阳性对照药物普瑞巴林灌胃治疗21天。通过代谢组学分析,明确XSF在体内的主要血清代谢产物和代谢途径。通过网络药理学和液相色谱–质谱仪分析,探究XSF治疗NP的主要活性成分和可能作用靶点。在此基础上,进一步整合代谢组学和网络药理学研究结果,使用Cytoscape 3.9.1绘制XSF治疗NP的“靶点–代谢途径–代谢物”网络关系图,并通过分子对接进行结果验证。结果:通过代谢组学分析,共获得XSF治疗NP中具有显著变化的差异代谢物11个,并通过功能富集分析获得了8条相关代谢通路。进一步通过联合代谢组学和网络药理学研究发现,“单胺氧化酶A(MAOA)/单胺氧化酶B(MAOB)/酪氨酸酶(TYR)–酪氨酸代谢途径–龙胆酸钠”可能是XSF治疗NP的重要网络途径。此外,分子对接结果显示XSF的活性成分与MAOA、MAOB和TYR(结合能<-5 kcal/mol)之间均具有高亲和力且相互作用稳定。结论:我们的发现进一步明确了XSF治疗NP的镇痛药效及作用机制,为XSF的临床应用和机制研究提供了科学基础。

构建Cu台阶位促进电催化CO_(2)还原制醇类化学品的研究

电催化CO_(2)制备高附加值的化学品是解决当前碳排放问题的可行技术路线之一.其中,合成醇类化合物因具有广泛用途和高价值而备受关注.在电催化CO_(2)还原合成多碳醇反应中,关键中间体*CH_(2)CHO容易发生热力学有利的脱氧反应而生成C2H4,降低了醇类产物的选择性.由于电催化CO_(2)还原是一个表面结构敏感的反应,因此可以通过设计Cu基催化剂的特定表面结构,实现对反应路径的有效调节,从而提升醇类产物的选择性.本课题组前期通过密度泛函理论(DFT)计算和主成分分析法等对Cu基催化剂的构效关系进行解析,说明配位不饱和的台阶位点有望高效地促进醇类产物的生成.本文进一步从实验角度,证明了配位不饱和的台阶位点是生成醇类产物的活性位点.本文采用CO分子作为还原剂制备了CuO衍生的金属Cu催化剂(COD-Cu),利用CO分子对Cu表面的重构作用,获得了具有丰富台阶位点的Cu催化剂.而通过H_(2)还原制备的金属Cu催化剂(HOD-Cu)对照样表面则多为平面位点.X射线衍射和原位拉曼光谱结果表明,CuO前驱体经过CO或H_(2)还原后被完全还原为金属态,并且在电化学还原条件下依旧呈现金属态,排除了催化剂价态对反应的影响.扫描电镜结果表明,两种催化剂的形貌没有明显区别,排除了催化剂形貌对反应的影响.高分辨透射电镜结果表明,COD-Cu表面因为CO的重构作用,产生相较于HOD-Cu更多的台阶位点,这与CO原位红外光谱结果一致(COD-Cu催化剂在2080 cm~(–1)波数处具有明显的台阶位点CO吸附峰).电化学CO_(2)还原活性测试结果表明,COD-Cu表现出更高的醇类产物选择性,相较于HOD-Cu,法拉第效率与部分电流密度均提升了5倍以上,醇类产物的法拉第效率达到40.5%,部分电流密度达到56.3 mAcm~(-2),产物中醇/烯烃比值为2.2.这表明台阶位点对调控反应路径促进醇类生成具有重要作用.结合原位衰减全反射表面增强傅里叶变换红外吸收光谱的阶跃电位和Ar气吹扫实验结果表明,COD-Cu因具有更多的台阶位点而表现出更高的催化CO_(2)到*CO反应活性,并有效促进后续的C–C偶联反应.通过热退火实验制备了具有不同台阶位点含量的COD-Cu催化剂,其台阶位点的含量与醇类产物的选择性保持良好的线性关系,进一步验证了台阶位点是促进醇类产物生成活性位点的结论.DFT结果也表明,台阶位点可以有效的提升关键中间体*CH_(2)CHO中C–O键强度,从而抑制C–O键断裂,促进醇类产物的生成.综上,本文提出了一种通过催化剂活性位点设计调控电催化CO_(2)还原反应路径的有效策略,为解析催化剂构效关系、明确活性位点提供参考.得益于催化科学的快速发展,具有高活性的CO_(2)还原电催化剂不断涌现,未来可在发展活性位点精细化调控方法、开发新型原位瞬态表征技术、创新催化剂失活机制原位研究方法等方面做出更多的努力.