Competitive Redox Chemistries in Vanadium Niobium Oxide for Ultrafast and Durable Lithium Storage

Niobium pentoxide(Nb_(2)O_(5))anodes have gained increasing attentions for high-power lithium-ion batteries owing to the outstanding rate capability and high safety.However,Nb2O5 anode suffers poor cycle stability even after modified and the unrevealed mechanisms have restricted the practical applications.Herein,the over-reduction of Nb5+has been demonstrated to be the critical reason for the capacity loss for the first time.Besides,an effective competitive redox strategy has been developed to solve the rapid capacity decay of Nb_(2)O_(5),which can be achieved by the incorporation of vanadium to form a new rutile VNbO_(4)anode.The highly reversible V^(3+)/V^(2+)redox couple in VNbO_(4)can effectively inhibit the over-reduction of Nb^(5+).Besides,the electron migration from V^(3+)to Nb5+can greatly increase the intrinsic electronic conductivity for VNbO4.As a result,VNbO4 anode delivers a high capacity of 206.1 mAh g^(−1)at 0.1 A g^(−1),as well as remarkable cycle performance with a retention of 93.4%after 2000 cycles at 1.0 A g^(−1).In addition,the assembled lithium-ion capacitor demonstrates a high energy density of 44 Wh kg^(−1)at 5.8 kW kg^(−1).In summary,our work provides a new insight into the design of ultra-fast and durable anodes.

Synthesis of melamine-formaldehyde microcapsules containing oil-based fragrances via intermediate polyacrylate bridging layers

A general and versatile strategy to prepare melamine-formaldehyde(MF)microcapsules encapsulating oil-based fragrances by combining solvent evaporation and in situ polymerization was proposed in this work.The oil-based fragrance was pre-encapsulated by an inner polyacrylate membrane via solvent evaporation,followed by in situ polymerization of MF precondensates as an outer shell.The polyacrylate membrane is used as an intermediate bridging layer to stabilize the oil-based fragrance,and to provide driving forces for in situ polymerization of MF precondensates through electrostatic attractions between carboxyl groups and ammonium ions.It was demonstrated that MF microcapsules containing clove oil were prepared successfully.The amount and the composition of the intermediate polyacrylate bridging layer were critical.Smooth and sphere-shaped MF-clove oil microcapsules were prepared when the weight ratio of polyacrylate to clove oil was over 60 wt%and the concentration of acrylic acid(AA)increased to 10 wt%in polyacrylate.In addition,MF microcapsules containing sunflower oil and hexyl salicylate were prepared by using this method.The work suggests that this new approach can be potentially used to encapsulate various core materials,tuning the shell properties of microcapsules such as thickness,mechanical strength and release properties.

基于监督学习模型的央行沟通测度

央行沟通是受到市场广泛关注的重要叙事文本,如何从高维文本中有效提取关键信息是有待深入研究的科学问题.本文将Ke et al.(2019)提出的基于文本筛选和主题建模情感提取模型运用到央行沟通测度中,具有简单透明、可复制性强的优势.结合中文文本特征和中国货币政策多工具的框架,选取多个货币政策实际干预的变动值作为监督变量进而构建央行沟通指数,并基于广义货币政策规则对未来货币政策实际干预进行预测.研究结果表明,央行沟通文本信息有助于提供额外预测能力,并且与现有文献基于关键措辞、监督词典和LDA主题模型等文本分析方法构建的指数相比,本文构建的指数对未来货币政策实际干预的预测能力更好,尤其是长期预测表现更为优越.本文从预测角度验证了央行沟通引导政策预期的有效性,提供了根据不同预测指标提取文本大数据信息的可行方案.

In situ self-assembled organoid for osteochondral tissue regeneration with dual functional units

The regeneration of hierarchical osteochondral units is challenging due to difficulties in inducing spatial,directional and controllable differentiation of mesenchymal stem cells(MSCs)into cartilage and bone compartments.Emerging organoid technology offers new opportunities for osteochondral regeneration.In this study,we developed gelatin-based microcryogels customized using hyaluronic acid(HA)and hydroxyapatite(HYP),respectively for inducing cartilage and bone regeneration(denoted as CH-Microcryogels and OS-Microcryogels)through in vivo self-assembly into osteochondral organoids.The customized microcryogels showed good cytocompatibility and induced chondrogenic and osteogenic differentiation of MSCs,while also demonstrating the ability to self-assemble into osteochondral organoids with no delamination in the biphasic cartilage-bone structure.Analysis by mRNA-seq showed that CH-Microcryogels promoted chondrogenic differentiation and inhibited inflammation,while OS-Microcryogels facilitated osteogenic differentiation and suppressed the immune response,by regulating specific signaling pathways.Finally,the in vivo engraftment of pre-differentiated customized microcryogels into canine osteochondral defects resulted in the spontaneous assembly of an osteochondral unit,inducing simultaneous regeneration of both articular cartilage and subchondral bone.In conclusion,this novel approach for generating self-assembling osteochondral organoids utilizing tailor-made microcryogels presents a highly promising avenue for advancing the field of tissue engineering.

跨越省际移民中的文化壁垒:信息沟通与身份认同

中国存在源远流长、各具特色的地域文化,文化差异是否成为影响劳动力跨区域流动的隐形壁垒?本文利用基因、姓氏和方言等群体特征数据,通过主成分方法构建省际文化差异的度量指标。研究表明:在控制地理和经济因素之后,文化差异对2000—2010年的省际移民具有显著的阻碍效应,并且这种阻碍效应随着时间的推移逐渐减缓,工具变量估计等稳健性分析均支持这一发现。进一步分析显示,信息沟通与身份认同是文化差异影响省际移民的两个主要机制。

货币政策不确定性是中国股票市场的定价因子吗?

本文以M2增长率度量中国的数量型货币政策,基于结构向量自回归模型和随机波动率模型测度货币政策不确定性(MPU)指数,发现其具有明显的反周期特征。在随机折现因子模型框架下对MPU指数进行截面定价。研究结果表明:MPU因子定价核的系数显著为正,风险溢价显著为负;在Fama-French的25个规模账面市值比投资组合中,控制其他风险因子之后,最低MPUβ投资组合的收益要比最高MPUβ投资组合的收益平均每年高出1.428%,即MPU是中国股市的重要定价因子。

膝骨关节炎患者生活质量和非手术治疗方式的多中心横断面研究

目的探究膝骨关节炎患者健康相关生活质量(HRQoL)的影响因素,并分析膝骨关节炎的非手术治疗方式。方法收集2017年12月至2018年11月在北京市五家医院骨科门诊就诊的膝骨关节炎患者的人口统计学变量、治疗方式、影像学资料以及12条目简短生命质量量表(SF-12)评分,分析HRQoL的影响因素及非手术治疗方式。结果共纳入2034例患者,男530例(26.1%),女1504例(73.9%),年龄(59.17±10.22)岁。在躯体生活质量方面,与男性相比,女性膝骨关节炎患者的生理总评分较低(β=-0.521,P=0.036);与年龄<55岁者相比,年龄≥64岁者生理总评分较低(β=-0.636,P=0.026);与受教育年限≤9年的人群相比,受教育年限≥13年的人群生理总评分较高(β=1.063,P<0.001);与轻度临床症状者相比,中度临床症状者生理总评分较低(β=-0.860,P=0.002),而重度临床症状者则更低(β=-1.126,P<0.001)。与未经治疗者相比,采用多种方式联合治疗者生理总评分较高(β=0.731,P=0.005)。在心理生活质量方面,与久坐工作人群相比,轻度体力工作人群的心理总评分较低(β=-0.712,P=0.015);与Charson合并症指数为0的人群相比,Charson合并症指数≥2的人群心理总评分较低(β=-1.183,P=0.007)。在过去的12个月中,使用过非甾体类抗炎药、对乙酰氨基酚、氨基葡萄糖/软骨素制剂、物理治疗、关节腔穿刺注射药物、中医治疗以及运动治疗的患者分别为648例(31.9%)、143例(7.0%)、406例(20.0%)、680例(33.4%)、343例(16.9%)、681例(33.5%)、170例(8.4%)。使用单一治疗和联合治疗的患者分别为451例(22.2%)、889例(43.7%)。结论北京市膝骨关节炎患者的非手术治疗方式以非甾体抗炎药、理疗和中医治疗为主,联合治疗的使用比例高于单一治疗。躯体生活质量与性别、年龄、受教育程度、症状严重程度及治疗方式相关,而心理生活质量与职业劳动性质和合并症相关。

颜值与公平感知——基于中国劳动力动态调查数据的实证研究

颜值作为个人天生禀赋是否影响其公平感知?本文基于中国劳动力动态调查数据(CLDS)的实证研究发现:个体颜值越高,则越感到公平,社会地位是两者关系的重要中介渠道。机制分析表明颜值主要通过人际技能信号机制产生影响,而非偏好机制,具体表现为:第一,相比女性,男性的颜值对于社会地位以及公平感知的影响更为显著,这与中国"郎才女貌"的传统偏好倾向不同;第二,在对人际技能要求更高的职业中,颜值对公平感知与社会地位的影响更为重要;第三,相比于年轻人,中老年人颜值的影响更大;第四,颜值与朋友圈规模之间具有倒U形关系,颜值次高者拥有最多密切朋友数量。