Probing the electric double layer structure at nitrogen-doped graphite electrodes by constant-potential molecular dynamics simulations

Electric double layer(EDL)is a critical topic in electrochemistry and largely determines the working performance of lithium batteries.However,atomic insights into the EDL structures on heteroatom-modified graphite anodes and EDL evolution with electrode potential are very lacking.Herein,a constant-potential molecular dynamics(CPMD)method is proposed to probe the EDL structure under working conditions,taking N-doped graphite electrodes and carbonate electrolytes as an example.An interface model was developed,incorporating the electrode potential and atom electronegativities.As a result,an insightful atomic scenario for the EDL structure under varied electrode potentials has been established,which unveils the important role of doping sites in regulating both the EDL structures and the following electrochemical reactions at the atomic level.Specifically,the negatively charged N atoms repel the anions and adsorb Li~+at high and low potentials,respectively.Such preferential adsorption suggests that Ndoped graphite can promote Li~+desolvation and regulate the location of Li~+deposition.This CPMD method not only unveils the mysterious function of N-doping from the viewpoint of EDL at the atomic level but also applies to probe the interfacial structure on other complicated electrodes.

Mitigated reaction kinetics between lithium metal anodes and electrolytes by alloying lithium metal with low-content magnesium

Lithium(Li)metal is regarded as a promising anode candidate for high-energy-density rechargeable batteries.Nevertheless,Li metal is highly reactive against electrolytes,leading to rapid decay of active Li metal reservoir.Here,alloying Li metal with low-content magnesium(Mg)is proposed to mitigate the reaction kinetics between Li metal anodes and electrolytes.Mg atoms enter the lattice of Li atoms,forming solid solution due to the low amount(5 wt%)of Mg.Mg atoms mainly concentrate near the surface of Mg-alloyed Li metal anodes.The reactivity of Mg-alloyed Li metal is mitigated kinetically,which results from the electron transfer from Li to Mg atoms due to the electronegativity difference.Based on quantitative experimental analysis,the consumption rate of active Li and electrolytes is decreased by using Mgalloyed Li metal anodes,which increases the cycle life of Li metal batteries under demanding conditions.Further,a pouch cell(1.25 Ah)with Mg-alloyed Li metal anodes delivers an energy density of 340 Wh kg^(-1)and a cycle life of 100 cycles.This work inspires the strategy of modifying Li metal anodes to kinetically mitigate the side reactions with electrolytes.

A comparative study of the land-atmosphere energy and water exchanges over the Tibetan Plateau and the Yangtze River Region

正确认识不同区域能量和水分循环特征是研究局地地气相互作用及准确预测区域天气,气候变化的关键.为了研究属于干旱/半干旱气候的青藏高原(TP)和湿润/半湿润气候的长江流域(YRR)之间地表能量和水分交换的异同,本文对比分析了两个区域8个不同地表类型(包括高山荒漠,高山草地,(平原)城市和(平原)草地等)观测站点的地表辐射和能量通量数据.结果显示:(1)TP由于高原大气层稀薄且空气洁净,年平均入射短波辐射为251.3W m^(-2),是YRR的1.7倍.加之高原地表反照率高导致反射辐射(59.6 W m^(-2))是YRR的2.87倍.入射及出射的长波辐射为231.5和338.0 W m^(-2),分别为YRR的0.64和0.83.而两个区域的净辐射差异不大;(2)草地站更多的潜热释放使得地表总加热效率高于城市和高山荒漠,TP和YRR的草地站的年平均潜热分别为35.0和38.8 W m^(-2),而植被稀疏且土壤干燥的高山荒漠地区感热最大,年平均感热为42.1 W m^(-2);其次是城市下垫面,其年平均感热为37.7 W m^(-2).研究结果揭示了不同气候背景下典型下垫面地气相互作用特征,为地气相互作用过程深入分析奠定了基础.

Earth Summit Mission 2022:Scientific Expedition and Research on Mt.Qomolangma Helps Reveal the Synergy between Westerly Winds and Monsoon and the Resulting Climatic and Environmental Effects

“Earth summit mission 2022”is one of the landmark scientific research activities of the Second Tibetan Plateau Scientific Expedition and Research(STEP).This scientific expedition firstly used advanced technology and methods to detect vertical meteorological elements and produce forecasts for mountain climbing.The“Earth summit mission 2022”Qomolangma scientific expedition exceeded an altitude of over 8000 meters for the first time and carried out a comprehensive scientific investigation mission on the summit of Mt.Qomolangma.Among the participants,the westerly–monsoon synergy and influence team stationed in the Mt.Qomolangma region had two tasks:1)detecting the vertical structure of the atmosphere for parameters such as wind,temperature,humidity,and pressure with advanced instruments for high-altitude detection at the Mt.Qomolangma base camp;and 2)observing extreme weather processes to ensure that members of the mountaineering team could successfully reach the top.Through this scientific expedition,a better understanding of the vertical structure and weather characteristics of the complex area of Mt.Qomolangma is gained.

Autophagy and multidrug resistance in cancer

Multidrug resistance(MDR) occurs frequently after long-term chemotherapy, resulting in refractory cancer and tumor recurrence.Therefore, combatting MDR is an important issue. Autophagy, a self-degradative system, universally arises during the treatment of sensitive and MDR cancer. Autophagy can be a double-edged sword for MDR tumors: it participates in the development of MDR and protects cancer cells from chemotherapeutics but can also kill MDR cancer cells in which apoptosis pathways are inactive. Autophagy induced by anticancer drugs could also activate apoptosis signaling pathways in MDR cells, facilitating MDR reversal. Therefore, research on the regulation of autophagy to combat MDR is expanding and is becoming increasingly important. We summarize advanced studies of autophagy in MDR tumors, including the variable role of autophagy in MDR cancer cells.

Cancer stem-like cells directly participate in vasculogenic mimicry channels in triple-negative breast cancer

Objective: Vasculogenic mimicry(VM) channels that are lined by tumor cells are a functional blood supply in malignant tumors.However, the role of VM-initiating cells remains poorly understood. Cancer stem-like cells(CSCs) are positively correlated with VM. In this study, triple-negative breast cancer(TNBC) enriched with CSCs was used to investigate the relationship between VM and CSCs.Methods: The expression of several CSC markers was detected by immunohistochemistry in 100 human breast cancer samples.The clinical significance of CSC markers and the relationship between VM, CSCs, breast cancer subtypes, and VM-associated proteins were analyzed. CD133+ and ALDH+ human and mouse TNBC cells were isolated by FACS to examine the ability of VM formation and the spatial relationship between VM and CSCs.Results: CSCs were associated with TNBC subtype and VM in human invasive breast cancer. CSCs in TNBC MDA-MB-231 cells formed more VM channels and expressed more molecules promoting VM than the non-TNBC MCF-7 cells in vitro. MDA-MB-231 cells that encircled VM channels on Matrigel expressed CD133. Moreover, CSCs were located near VM channels in the 3D reconstructed blood supply system in human TNBC grafts. The CD133+ and ALDH+ cells isolated from TA2 mouse breast cancer formed more VM channels in vivo.Conclusions: CSCs line VM channels directly. Additionally, CSCs provide more VM-related molecules to synergize VM formation. The signaling pathways that control CSC differentiation may also be potential treatment targets for TNBC.

Polar interaction of polymer host-solvent enables stable solid electrolyte interphase in composite lithium metal anodes

The lithium(Li) metal anode is an integral component in an emerging high-energy-density rechargeable battery.A composite Li anode with a three-dimensional(3 D) host exhibits unique advantages in suppressing Li dendrites and maintaining dimensional stability.However,the fundamental understanding and regulation of solid electrolyte interphase(SEI),which directly dictates the behavior of Li plating/stripping,are rarely researched in composite Li metal anodes.Herein,the interaction between a polar polymer host and solvent molecules was proposed as an emerging but effective strategy to enable a stable SEI and a uniform Li deposition in a working battery.Fluoroethylene carbonate molecules in electrolytes are enriched in the vicinity of a polar polyacrylonitrile(PAN) host due to a strong dipole-dipole interaction,resulting in a LiF-rich SEI on Li metal to improve the uniformity of Li deposition.A composite Li anode with a PAN host delivers 145 cycles compared with 90 cycles when a non-polar host is employed.Moreover,60 cycles are demonstrated in a 1:0 Ah pouch cell without external pressure.This work provides a fresh guidance for designing practical composite Li anodes by unraveling the vital role of the synergy between a 3 D host and solvent molecules for regulating a robust SEI.

Hypoxic microenvironment induced spatial transcriptome changes in pancreatic cancer

Objective: Hypoxia is a significant feature of solid tumors, including pancreatic ductal adenocarcinoma(PDAC). It is associated with tumor invasion, metastasis, and drug resistance. However, the spatial distribution of hypoxia-related heterogeneity in PDAC remains unclear.Methods: Spatial transcriptomics(STs), a new technique, was used to investigate the ST features of engrafted human PDAC in the ischemic hind limbs of nude mice. Transcriptomes from ST spots in the hypoxic tumor and the control were clustered using differentially-expressed genes. These data were compared to determine the spatial organization of hypoxia-induced heterogeneity in PDAC. Clinical relevance was validated using the Tumor Cancer Genome Atlas and KM-plotter databases. The CMAP website was used to identify molecules that may serve as therapeutic targets for PDAC.Results: ST showed that the tumor cell subgroups decreased to 7 subgroups in the hypoxia group, compared to 9 subgroups in the control group. Different subgroups showed positional characteristics and different gene signatures. Subgroup 6 located at the invasive front showed a higher proliferative ability under hypoxia. Subgroup 6 had active functions including cell proliferation, invasion, and response to stress. Expressions of hypoxia-related genes, LDHA, TPI1, and ENO1, induced changes. CMAP analysis indicated that ADZ-6482, a PI3 K inhibitor, was targeted by the invasive subgroup in hypoxic tumors.Conclusions: This study is the first to describe hypoxic microenvironment-induced spatial transcriptome changes in PDAC, and to identify potential treatment targets for PDAC. These data will provide the basis for further investigations of the prognoses and treatments of hypoxic tumors.

The chemical origin of temperature-dependent lithium-ion concerted diffusion in sulfide solid electrolyte Li_(10)GeP_(2)S_(12)

Solid-state batteries have received increasing attention in scientific and industrial communities,which benefits from the intrinsically safe solid electrolytes(SEs).Although much effort has been devoted to designing SEs with high ionic conductivities,it is extremely difficult to fully understand the ionic diffusion mechanisms in SEs through conventional experimental and theoretical methods.Herein,the temperature-dependent concerted diffusion mechanism of ions in SEs is explored through machinelearning molecular dynamics,taking Li_(10)GeP_(2)S_(12) as a prototype.Weaker diffusion anisotropy,more disordered Li distributions,and shorter residence time are observed at a higher temperature.Arrhenius-type temperature dependence is maintained within a wide temperature range,which is attributed to the linear temperature dependence of jump frequencies of various concerted diffusion modes.These results provide a theoretical framework to understand the ionic diffusion mechanisms in SEs and deepen the understanding of the chemical origin of temperature-dependent concerted diffusions in SEs.

玻化微珠在无机保温承重材料中的传热机理分析

细观尺度是宏观特征和微观组成之间联系的纽带,对混凝土进行细观尺度的研究,能够形象地揭示混凝土各组成成分对整体性能的传热机理,是研究该类型保温混凝土传热机理的一种有效方法。研究了保温骨料粒径、所占体积比对保温混凝土有效导热系数的影响,并建立了保温混凝土细观模型,针对其保温特性,采用有限元模拟的方式对保温混凝土温度场和热流通道进行了分析。研究表明:保温骨料所占体积比越大,导热系数越低;当保温骨料粒径在0.315~0.63 mm时,混凝土能够获得较好的导热系数;随着保温骨料占比的逐渐增大,保温骨料类似于“热阻器”,能够使粗骨料与砂浆形成的大热流通道不断被阻隔、压缩,大热流通道在混凝土试件中的比例不断缩小,从而使混凝土整体热阻增大,传热能力减弱。

骨料级配和压缩比对聚乙烯醇基膨胀珍珠岩保温板性能的影响研究

研究了膨胀珍珠岩级配和保温板压缩比对聚乙烯醇(PVA)基膨胀珍珠岩保温板物理力学性能的影响。结果表明:膨胀珍珠岩级配后的堆积密度越大制备的保温板干密度越大;保温板的干密度、抗压强度和导热系数随着压缩比的增加而增大,当压缩比增大到1.6~2.2时,保温板的导热系数与干密度呈线性相关;以改性PVA为胶黏剂,合理确定骨料级配,压缩比为2.0时,制备得到干密度159.5~168.6 kg/m3、抗压强度0.313~0.332 MPa、导热系数0.0527~0.0545 W/(m·K)的PVA基膨胀珍珠岩保温板。

非金属矿物材料在无机保温材料中的应用及进展

新型无机保温材料作为一种功能材料,近些年发展迅速,在工业和建筑领域已得到广泛应用。非金属矿物材料具有耐高温、低导热的优势,是一种难燃材料,作为增强保温材料特性的一种主要原材料,已经广泛应用于无机保温材料,对新型无机保温材料的研究开发起到了助推作用。

蛭石膨胀性能影响因素试验研究

以产自河北灵寿和新疆尉犁的两种蛭石为原料,在化学成分、矿物组成测试分析的基础上,开展蛭石膨胀性能影响因素试验研究。通过研究得出不同产地的蛭石化学成分及矿物组成均有较大差异;蛭石中TFe_2O_3含量影响膨胀蛭石的外观及膨胀性能,随着TFe_2O_3含量的增加,膨胀蛭石颜色加深,由银白色变为金黄色,膨胀温度由1 000℃降到850℃,粉化率也随之增加;过多延长蛭石膨胀时间会导致膨胀蛭石粉化率增加,影响膨胀蛭石的应用性能。

Existence of Solutions for Boundary Value Problems of Vibration Equation with Fractional Derivative

In this paper, we investigate the solvability of boundary value problems for a class of vibration differential equation describing the fractional order damped system with signal stimulus. By presenting kernel function through the Laplace transform, and using the eigenvalue and the improved Leray-Schauder degree, the existence of solutions for boundary value problems is established.

Plasma-Etching of the Organic Layer in Nacre

Nacre’s brick and mortar structure has been motivating innovations in biomimetic materials for decades. However, there is still room to improve understanding of the structure of the organic layer in order to engineer better biomimetic composites. A plasma-etching technique that allows for the selective removal of some organic components from individual layers is developed. We conclude that this technique enables a closer examination of the organic layer such that the locations and mechanical properties of individual components can be determined. A methodology for examining nacre samples that have not been demineralized provides a more accurate substrate for understanding the structure-property relationships of the organic layer in native nacre.

城市桥梁集群现代化运维管理策略研究

文章结合桥梁养护管理工作实践,研究治理能力现代化建设背景下城市桥梁集群运维管理提升的策略,以更好地统筹城市桥梁安全运行。基于桥梁各构件单元,探索加强基础数据管理、技术状况评估与运维成本动态优化,强化养护施工、台账管理,推进部门协同联动,建立城市桥梁集群运维数字化、信息化、一体化、可视化的管理目标,为架构智慧城市桥梁运维平台做准备。

Z型电荷分离介导的0D/2D AgVO_(3)/TiO_(2)异质结用于增强光催化CO_(2)还原

合理利用Z型电荷调节机制是提高光催化CO_(2)还原效率的有效策略.在本工作中,通过将AgVO_(3)量子点(QDs)原位锚定在TiO_(2)纳米片(NSs)上,从而构建了0D/2D AgVO_(3)/TiO_(2)直接Z型异质结光催化剂.TiO_(2)NSs抑制了AgVO_(3)量子点自身的团聚,从而优化了体系的形貌结构.AgVO_(3)QDs增强了复合材料的光吸收能力,从而提高了对太阳光的利用效率.同时,两种单体之间匹配的能带结构和合适的内部界面电场(即(-)AgVO_(3)/(+)TiO_(2))促进了直接Z型异质结的构建,从而显著促进了光生电子-空穴对的分离,并保持了体系中最高的氧化还原电位.优化后的AgVO_(3)/TiO_(2)复合材料在没有任何助催化剂的情况下,表现出具有竞争力的光催化CO_(2)还原效率(CO,47.61μmol h-1g-1),是原始TiO_(2)NSs的20.97倍.本工作提出了一种直接Z型异质结的合理设计方法,为高效光催化CO_(2)还原催化剂的开发提供了指导.

The Earth Summit Mission-2022:Successful ozone soundings contribute to source identification in the north Mt.Qomolangma region

As part of“The Earth Summit Mission-2022”during the second Tibetan Plateau Scientific Expedition and Research(STEP)in April and May 2022,we conducted the ozone sounding experiment(an ozonesonde mated to a radiosonde)at Mt.Qomolangma Base Camp(MQBC;86.85°E,28.14°N;5200 m),a location at an extremely high altitude.A total of ten sounding profiles were obtained between April 30 and May 06,2022,of which seven profiles were above35 km in altitude,with a maximum detection altitude up to 39.0 km.This study presents the temporal variation and vertical distributions of atmospheric temperature,humidity,and ozone during the MQBC campaign.The averaged ozone concentration was high(68.3 ppbv)at the surface and then increased smoothly until peaking(~110 ppbv)in the middle troposphere(approximately 10 km),and afterward,the ozone concentration increased rapidly from the upper troposphere to a maximum of~10 ppmv at~30 km.The enhanced ozone concentration in the middle troposphere was associated with the blocking high pressure,and transport from the southern flank of the Himalayas occurred during the campaign period.The average total ozone column was 291.9±21.4 DU for the seven profiles exceeding 35km in altitude.The ozonesonde measurements were also compared with the vertical ozone profiles retrieved from the space-borne ozone products from the Microwave Limb Sounder(MLS)onboard the Aura satellite and the Atmospheric Infrared Sounder(AIRS)onboard the Aqua satellite.

High-performance localized high-concentration electrolytes by diluent design for long-cycling lithium metal batteries

Electrolyte design is essential for stabilizing lithium metal anodes and localized high-concentration electrolyte(LHCE) is a promising one. However, the state-of-the-art LHCE remains insufficient to ensure long-cycling lithium metal anodes. Herein, regulating the solvation structure of lithium ions in LHCE by weakening the solvating power of diluents is proposed for improving LHCE performance. A diluent,1,1,2,2,3,3,4,4-octafluoro-5-(1,1,2,2-tetrafluoroethoxy) pentane(OFE), with weaker solvating power is introduced to increase the proportion of aggregates(an anion interacts with more than two lithium ions,AGG-n) in electrolyte compared with the commonly used 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether(TTE). The decomposition of AGG-n in OFE-based LHCE intensifies the formation of anion-derived solid electrolyte interphase and improves the uniformity of lithium deposition. Lithium metal batteries with OFE-based LHCE deliver a superior lifespan of 190 cycles compared with 90 cycles of TTE-based LHCE under demanding conditions. Furthermore, a pouch cell with OFE-based LHCE delivers a specific energy of 417 Wh/kg and undergoes 49 cycles. This work provides guidance for designing high-performance electrolytes for lithium metal batteries.

Chemical constituents from endophytic fungus Plectosphaerella cucumerina YCTA2Z1 of Cynanchum auriculatum

Objective： To study the chemical constituents from the Et OAc extract of endophytic fungal Plectosphaerella cucumerina YCTA2 Z1.Methods： The chemical constituents were isolated and purified by silica gel column,Sephadex LH-20,and reverse-phase C-18 column chromatography as well as crystallization.Results： Thirteen compounds were isolated from the EtOAc extract of the fungal strain YCTA2 Z1.Their chemical structures were elucidated according to the spectral evidence.They were identified as caudatin（1）,baishouwubenzophenone（2）,cynandione B（3）,asterbatanoside A（4）,p-hydroxyphenethyl-O-β-D-glycoside（5）,caffeic acid（6）,ferulic acid（7）,2,5-dihydroxyacetophenone（8）,protocatechuic acid（9）,vanillic acid（10）,stearic acid（11）,azelaic acid（12）,and succinic acid（13）.Conclusions： It is the first chemical study on endophytic fungi from Cynanchum auriculatum and all the compounds are obtained from the species,the genus,as well as the family Plectosphaerellaceae for the first time.