Tribological and rheological performance of lithium grease with poly-a-olefin and alkyl-tetralin as base oils

A new category of lithium greases was synthesized by using poly-a-olefin(PAO8) and alkyl-tetralin as base oil, where the alkyl-tetralins were synthesized by the alkylation of tetralin and olefins. The influence of thickener concentration, alkyl-tetralin content and type of blend oils on the rheological and tribological performance of lithium grease was investigated. The microstructures of soap fibers were measured to reveal the structure-property correlations. The concentration of thickener and alkyl-tetralin content obviously affect the lubricating performance of lithium grease, while the molecular structure of alkyltetralin has no obvious impact on their properties. It was found that alkyl-tetralin could significantly enhance the thickening ability of PAO8 base oils, and decrease the amount of thickeners by 1.5%(mass).Lithium greases prepared using 20%(mass) alkyl-tetralin as co-base oil exhibited high colloidal stability,excellent rheological behaviors and tribological properties.

Combined QTL mapping,GWAS and transcriptomic analysis revealed a candidate gene associated with the timing of spring bud flush in tea plant(Camellia sinensis)

Dear Editor,The timing of the spring bud f lush(TBF)is a crucial agro-nomic trait for the tea plant,as it strongly influences the yield and economic value of harvested fresh tea leaves.The TBF of tea plant is generally defined as the date when>30%of the growing tender shoots have reached the stage of one bud with one to three leaves,referred as to the stage of one and a bud,two and a bud,and three and a bud,respectively.

Experimental study on uniaxial ratchetting-fatigue interaction of extruded AZ31 magnesium alloy with different plastic deformation mechanisms

The uniaxial ratchetting-fatigue interaction of extruded AZ31 magnesium(Mg)alloy is investigated by uniaxial stress-controlled cyclic tests at room temperature and with addressing the roles of different plastic deformation mechanisms.Different stress levels are prescribed to reflect the cyclic plasticity of the alloy controlled by diverse deformation mechanisms(i.e.,dislocation slipping,deformation twinning and detwinning ones),and then the influences of stress level and stress rate on the ratchetting and fatigue life are discussed.The experimental results demonstrate that different evolution characteristics of whole-life ratchetting and fatigue life presented during cyclic tests with various mean stresses,stress amplitudes and stress rates are determined by the dominated plastic deformation mechanisms.It’s worth noting that the ratchetting can occur in the compressive direction even in the cyclic tests with a positive(tensile)mean stress,and the fatigue life increases first and then decreases with the increase of mean stress on account of the interaction between dislocation slipping and twinning/detwinning mechanisms.Comparing the fatigue lives obtained in the asymmetric stress-controlled and symmetrical strain-controlled cycle tests,it is seen that the ratchetting deformation causes an additional damage,and then leads to a shortening of fatigue life.

Affinity-Engineered Flexible Scaffold toward Energy-Dense, Highly Reversible Na Metal Batteries

The practical deployment of metallic anodes in the energy-dense batteries is impeded by the thermodynamically unstable interphase in contact with the aprotic electrolyte,structural collapse of the substrates as well as their insufficient affinity toward the metallic deposits.Herein,the mechanical flexible,lightweight(1.2 mg cm^(−2))carbon nanofiber scaffold with the monodispersed,ultrafine Sn_(4)P_(3) nanoparticles encapsulation(Sn_(4)P_(3)NPs@CNF)is proposed as the deposition substrate toward the high-areal-capacity sodium loadings up to 4 mAh cm^(−2).First-principles calculations manifest that the alloy intermediates,namely the Na_(15)Sn_(4) and Na_(3)P matrix,exhibit the intimate Na affinity as the“sodiophilic”sites.Meanwhile,the porous CNF regulates the heterogeneous alloying process and confines the deposit propagation along the nanofiber orientation.With the precise control of pairing mode with the NaVPO4F cathode(8.7 mg cm^(−2)),the practical feasibility of the Sn_(4)P_(3) NPs@CNF anode(1^(*)Na excess)is demonstrated in 2 mAh single-layer pouch cell prototype,which achieves the 95.7%capacity retention for 150 cycles at various mechanical flexing states as well as balanced energy/power densities.

非贵金属助催化剂Ni_3N修饰g-C_3N_4用于可见光催化产氢的研究（英文）

近年来,利用太阳光光解水制氢被认为是解决当前能源短缺和环境污染问题的重要途径之一.众所周知,助催化剂可以有效的降低光催化产氢反应的活化能,提供产氢反应的活性位点,有效的促进催化剂中光生载流子的传输与分离,从而提高光催化剂产氢体系的反应活性和稳定性.然而,鉴于贵金属助催化剂(Pt, Au和Pd等)储量低、成本高,极大地制约了其应用.因而,开发出适用于光催化水分解制氢的非贵金属助催化剂尤为重要.石墨相氮化碳(g-C_3N_4)因其具有热稳定性、化学稳定性高以及制备成本低廉等优点,成为光催化领域研究的热点.然而,由于g-C_3N_4的禁带宽度(Eg=2.7 eV)较宽,致使其对可见光的响应能力较弱,并且在光催化反应过程中其光生电子-空穴对易复合,从而导致其光催化产氢活性较低.因此,如何开发出含非贵金属助催化剂的g-C_3N_4高效、稳定的太阳光催化分解水制氢体系引起了人们极大的关注.本文通过水热法-高温氨化法首次将非贵金属Ni_3N作为助催化剂来修饰g-C_3N_4,增强其可见光光催化性能(l>420 nm).采用XRD、SEM、EDS、Mapping、UV-Vis、XPS和TEM等手段对Ni_3N/g-C_3N_4光催化体系进行了表征.结果表明, Ni_3N纳米颗粒成功的负载到g-C_3N_4表面且没有改变g-C_3N_4的层状结构.此外,采用荧光光谱分析(PL)、阻抗测试(EIS)和光电流谱进行表征,结果显示, Ni_3N纳米颗粒可有效促进催化剂中光生载流子的传输与分离,抑制电子-空穴对的复合.同时,将功率为300 W且装有紫外滤光片(λ>420 nm)的氙灯作为可见光光源进行光催化产氢实验结果表明,引入了一定量的Ni_3N可以极大提高g-C_3N_4的光催化活性,其中, Ni_3N/g-C_3N_4#3的产氢量为～305.4μmol·h-1·g-1,大约是单体g-C_3N_4的3倍.此外,在450nm单色光照射下, Ni_3N/g-C_3N_4光催化产氢体系的量子效率能达到～0.45%,表明Ni_3N/g-C_3N_4具有将入射电子转化为氢气的能力.循环产氢实验表明, Ni_3N/g-C_3N_4在光催化产氢过程中有着较好的产氢活性和稳定性.最后,阐述了Ni_3N/g-C_3N_4体系的光催化产氢反应机理.本文采用的原料价格低廉,性能优异,制备简单,所制材料在光催化制氢领域展现出重要前景.

贝伐珠单抗治疗非小细胞肺癌所致恶性胸腔积液的研究进展

肺癌是全球范围内发病率最高的恶性肿瘤,晚期肺癌所致的恶性胸腔积液(malignant pleural effusion,MPE)严重影响患者的生活质量和预后。MPE的治疗手段包括胸腔穿刺术、胸膜固定术、胸腔埋管引流、胸腔内灌注治疗等。血管内皮生长因子(vascular endothelial growth factor, VEGF)及其受体是一组影响血管生成的重要配体和受体,是控制血管生成的主要因素,在MPE的形成中发挥重要作用。贝伐珠单抗是一种重组的人源化VEGF单克隆抗体,可与内源性VEGF竞争性结合VEGF受体,抑制新血管生成以及降低血管通透性,阻碍胸腔积液形成,延缓肿瘤发展进程。本综述旨在讨论贝伐珠单抗治疗非小细胞肺癌所致恶性胸腔积液的研究进展,探讨贝伐珠单抗临床应用的方法、疗效、安全性以及未来的发展方向。

无贵金属光催化剂VC/CdS纳米线将苯甲醇选择性氧化为苯甲醛并产氢

太阳能制氢作为一种绿色、实用、可再生的能源生产技术越来越受到人们的关注.传统的光解水产氢通常用三乙醇胺、硫化钠/亚硫酸钠、乳酸、甲醇、抗坏血酸和甲醇等做牺牲剂,这些试剂的加入不仅会污染环境,还会增加制氢成本.而目前完全无牺牲剂体系的产氢效率普遍较低,使得发展经济绿色的牺牲剂体系尤为迫切.通过光催化在单一水性体系中同时生产可储存和可再生的氢气与高附加值的有机化学品是一种新兴环保的策略.本文采用简单的静电自组装和煅烧方法将碳化钒(VC)和CdS纳米线(NW)复合形成VC/CS.结果表明,与原始的CdS NWs相比,负载适量VC的CdS NWs的光催化活性显著提高.然而,同时促进光解水产氢和苯甲醇选择性氧化的机理仍需要进一步探究.X射线衍射谱、高倍透射电子显微镜、扫描透射电子显微镜以及光电子能谱结果表明,VC和CdS NW是紧密结合的,且Cd,S,C和V元素均匀分布,由于两者之间的紧密结合引起了催化剂颜色变化.紫外可见光谱(UV-Vis)结果表明,样品的光吸收范围增大,但吸收带边没有发生明显改变.当采用Na_(2)S·9H_(2)O和Na_(2)SO_(3)做牺牲剂时,VC/CS的产氢活性明显高于Pt负载的CdS,说明VC是一种非常有利于产氢的非贵金属助催化剂.当改用苯甲醇(BO)做牺牲剂时,产氢速率明显增加,同时苯甲醇选择性氧化成苯甲醛(BD).进一步增加VC的负载量,样品产氢活性先增加后减小;当VC的负载量达到15%(VC/CS-15)时,在可见光(λ>420 nm)照射2 h后产氢效率达到20.5 mmol g^(–1) h^(–1),BO转化率为41%,BD选择性超过99%,约为CdS NW的661倍.将光活性测试时间由2 h延长至4 h,BO转化率由41%提高到58%,但BD选择性降至88%.样品VC/CS-15上BD和H_(2)生成趋势与UV-Vis漫反射光谱结果一致,表明反应是通过光催化过程进行的.此外,VC/CS-15在单色420 nm处产生BD和H_(2)的表观量子效率约为7.5%.光催化活性的增强是由于VC的加入降低了样品的Zeta电位,使其对BO具有更强的吸附作用,同时VC在CdS NWs上的牢固附着为质子还原提供了更多的活性位点,通过减少电荷传输距离和提供更宽的电子传输通道来增强光生电子的传输.综上,本文设计的同时产氢和生成高附加值有机化学品的方法光解水产氢提供了新思路.

Distribution and partitioning of heavy metals in large anthropogenically impacted river, the Pearl River, China

In order to evaluate the distribution and partitioning characteristics of heavy metals in the large anthropogenically impacted Pearl River Basin, the contents of ‘‘anthropophile'' elements(Cr, Ni, Cu, Zn, Cd and Pb,which are clearly influenced by human activities) were determined, and their partitioning coefficients(Kd) between water and sediments and enrichment factors(EF) were calculated for samples collected at different locations along the Pearl River main stream. The modified BCR sequential extraction procedure(proposed by the European Community Bureau of Reference in 1993), which involves the successive extraction of metals in a decreasing order of reactivity, was applied. Sediment samples from the upper,middle, and lower reaches were included in this study. The results showed that the content of most metals in water and sediment samples gradually increases from upstream to downstream, suggesting a possible input from human activities as shown by their increasing high EF, ranged from 1.4 to 3.9 for Cu, from 1.4 to 6.7 for Zn, from 2.5 to59.1 for Cd, and from 1.7 to 8.9 for Pb, respectively. Thehigher partition coefficients(Kd) for Cr, Zn, and Pb(10~5–10~6) indicated that they were mainly transported in solid phase, while parts of Ni, Cu, and Cd were transported in dissolved phase as they display relatively lower Kdin the range of 10~4–10~5. According to the results of the BCR leaching, the percentage of non-residual fraction of heavy metals in the sediments showed a decreasing order of Cd [ Pb [ Zn [ Cu [ Ni [ Cr, implying that Cd and Pb were more active and bioavailable compared to the other four metals, and thus would be potentially more harmful to the watershed ecosystem.

Changes and determining factors of crop evapotranspiration derived from satellite-based dual crop coefficients in North China Plain

Evaluating actual crop evapotranspiration(ET) variations and their determining factors under changing climates is crucial for agricultural irrigation management and crop productivity improvement in nonhumid regions.This study analyzed the spatiotemporal characteristics and detected the determining factors of ETfor winter wheat and summer maize rotation system from 2000 to 2017 in the North China Plain(NCP),by combining the FAO-56 dual crop coefficient approach with remotely sensed vegetation indices(VIs).The results indicated that daily air temperature increased in varying degrees while wind speed and sunshine hours decreased slightly during the growing season of winter wheat and summer maize over the study period.The trends of relative humidity and effective precipitation varied in crop growing seasons.Based on the validated relationship of dual crop coefficients and VIs,the estimated multi-year average ETof winter wheat(370.29±31.28 mm) was much higher than summer maize(281.85±20.14 mm),and the rotation cycle was 652.43±27.67 mm.Annual ETof winter wheat and the rotation cycle increased by 2.96 mm aand 1,77 mm a,respectively.However,the ETof summer maize decreased with distinct spatial variation.Spatially,winter wheat ETincreased significantly in the northeast NCP,covering the Beijing-Tianiin-Hebei areas.Meanwhile,significant increases in summer maize ETwere detected in the southwest NCP.The sensitivity and contribution analysis showed that ETof winter wheat and summer maize was positively sensitive to temperature,wind speed,and sunshine hours while negatively to relative humidity.Moreover,wind speed and sunshine hours contributed most to changes in ET(around 20%-40%).

Preparation of CH_3NH_3PbI_3 thin films for solar cells via Vapor Transfer Method

Organometal halide perovskite based solar cells have emerged as one of the most promising candidates for low-cost and high-efficiency solar cell technologies. Here a Vapor Transfer Method （VTM） is used to fabricate high quality perovskite thin films in a balanced vacuum capsule. By adjusting the reaction tem- perature, CH_3NHl_3 saturated vapor which then reacts with Pbl_2 films can be controlled and the formation process of CH_3NH_3Pbl_3 perovskite films can be further influenced. Prepared perovskite films which ex- hibit pure phase, smooth surface and high crystallinity are assembled into planar heterojunction inverted solar cells. The whole fabrication process of solar cell devices is organic solution free. Finally, the cham- pion cell achieved power conversion efficiency （PCE） of 13.08% with negligible current-voltage hysteresis under fully open-air conditions. The photovoltaic performance could be further enhanced by optimizing perovskite composition and the device structure.

Evaluation of groundwater geochemical characteristics and quality in the central and Northern Shaanxi Province,China

Groundwater is of vital importance to many aspects of ecosystem services,especially in the central and northern Shaanxi Provence,China,-an area covered by loess deposits and short of water resources.We studied the solute geochemistry and water quality of groundwater in this area to improve the understanding of hydrogeochemical processes in loess deposits area.The results showed that the average pH of groundwaters was 8.03±0.36(1 SD)with large ranges(324-83,379 mg/L)of the total dissolved solids(TDS).The cations and anions followed the order of Na^+>Ca^2+>Mg^2+>K^+>SiO2 and HCO3>Cl^->SO4^2->F^->NO3^-.Most groundwater samples show the HCO3^--Na^+-Ca^2+water type and a small number of samples the Na^+-Cl^-type.Irrigation water quality assessments showed that 40%of the groundwater has good water quality,42%moderate water quality,and 18%(the upper reaches of Wuding River and Wei River)poor water quality with very high salinity.About 40%of groundwater samples were not suitable for drinking due to the high TDS,fluoride,sulfide,and chloride.Gibbs plot and stoichiometry analysis showed that carbonate weathering is the main source of groundwater chemistry in central Shaanxi Province while evaporite dissolution dominates in northern Shaanxi Provence.The loess weathering significantly influences the dissolved solutes of groundwater in the Loess Plateau.The ion-exchange between Mg^2+and Ca^2+in groundwater and Na^+in clay minerals and the deposition of carbonate minerals increased Na^+but decreased the Ca^2+in groundwater.Our research results improve our understanding of hydrogeochemical processes that affect the solutes chemistry of groundwater in the loess area and provide essential data to the global groundwater database.

Ecological Restoration Technology and Benefit Assessment of Karst Rocky Desertification Mountains in Xixiu District of Anshun City

Ecological restoration refers to the containment of soil erosion,restoration of water conservation,climate regulation,maintenance of ecological functions of biodiversity,and improvement of ecological environment and landscape pattern based on self-repairing capacity of the nature and combined with appropriate artificial measures. Since the natural restoration process of karst desertification mountain is very long,it needs to be supplemented by artificial vegetation restoration. This paper introduced the ecological restoration technologies implemented in karst rocky desertification mountains in Xixiu District,Anshun City of Guizhou Province,and also introduced the afforestation tending management measures. It assessed the ecological benefits of the ecological restoration project from five aspects: mountain community characteristics,vegetation coverage,species diversity,afforestation survival rate and landscape effect.

A Compact Wideband Dual-Polarized Printed Antenna with Coaxial Feeds for TD-SCDMA Application

In this article, a low-profile wideband dual-polarized planar printed dipole antenna, fed by coaxial lines, is investigated for the TD-SCDMA operation. The antenna is composed of two printed dipoles, two pairs of feeding coaxial lines and a ground. The single-polarized planar printed rectangular dipole and petal dipole, with the similar configuration, are first studied, exhibiting the potential wideband operation. Two petal dipoles are then cross-arranged to design a dual-polarized planar printed antenna, giving a lower profile and a better bandwidth covering the Chinese TD-SCDMA band (1880-2400 MHz). The dual-polarized antenna is simply excited by two pairs of coaxial feeds. Simulated and measured results show that the antenna achieves a common impedance bandwidth of 42% at both ports, good isolation of more than 25 dB, stable radiation patterns and the gain of about 7 dBi over the operating bandwidth.

Is Compulsory School a Heaven or a Hell?

With the development of education and the society revolution,in the last few years,the word“freedom”has been discussed intensely,and the debates on some items like human rights,racial discrimination and political liberty have never stopped.At the same time,the discussion of freedom in the field of education is also rising.This article quotes Lynda Barry and John Taylor Gatto’s paper,clearly analyzing the effect of compulsory education through 3 aspects:national identity,creative approach and personal psychology.

316L奥氏体不锈钢高温单拉和蠕变行为的实验和晶体塑性模拟研究

316L奥氏体不锈钢(ASS)因其优异的抗蠕变性和耐腐蚀性被广泛应用于核反应堆中的包壳材料.但由于核反应堆长期处于高温环境,其包壳材料会不断累积蠕变损伤并最终导致性能退化,进而影响设备的安全运行.因此,为保障核反应堆的安全服役,针对其包壳材料高温蠕变行为的研究具有重要意义.基于此,我们开展了316L ASS在高温下的单轴拉伸变形和蠕变行为的研究.结果表明,316L ASS的力学响应具有明显的温度依赖性,且在特定的温度范围(723 K-923 K)和应变率(1.3×10−3 s−1)条件下,显示出明显的动态应变时效效应;此外,316L ASS在高温条件下的主要蠕变机制为位错攀移机制,它一方面会影响位错密度的演化,另一方面会影响位错越过障碍物的激活频率.基于316L ASS在高温下的微结构演化机理,我们建立了基于位错机制的晶体塑性本构模型.在该模型中额外考虑了位错攀移机制对刃型位错湮灭、位错偶极子形成和刃型位错越过障碍物的贡献.最终结果表明,该模型能有效地模拟和预测316L ASS在高温条件下的单轴拉伸和蠕变响应,而该研究成果也为316L ASS的蠕变性能评估提供了重要的理论依据.

Ytterbium modified birnessite MnO_(2) for improving deep oxidation of toluene

A series of rare earth metals modified birnessite manganese dioxides(RE-Mn)was synthesized by hydrothermal method and their catalytic degradation of toluene was investigated.Yb-Mn shows the best toluene oxidation activity with the conversion of T50%and T99%at 196 and 226℃,respectively.The physiochemical characterizations identified that the high catalytic performance and excellent stability of Yb-Mn are mainly associated with its higher molar ratios of Mn^(4+)/Mn^(3+),more lattice oxygen(Olatt),and better mobility of surface adsorbed oxygen(O_(ads)).Moreover,it is confirmed that introduction of Yb into birnessite MnO_(2) facilitates the production of acetic acid at lower temperature.These results can aid the design of high-efficiency manganese oxide catalysts for the catalytic combustion of VOCs.

双缺陷工程RuO_(2)/D-Co_(3)O_(4)/CC复合材料作为引发酸性介质中氧析出反应的高效电催化剂

缺陷工程被认为是提高催化剂性能的有效方法,因为它能使催化剂具有丰富的活性位点和合适的结合能,从而提高催化性能.本文采用简单的电沉积和酸蚀刻方法制备了双缺陷工程RuO_(2)/D-Co_(3)O_(4)/CC(低Ru负载2.42 wt%)复合材料,用于增强酸性介质中的氧析出反应(OER).所制备的RuO_(2)/D-Co_(3)O_(4)/CC催化剂采用物理化学技术进行了深入表征,结果表明催化剂中存在明显的阴离子和阳离子缺陷.实验研究表明具有双重缺陷的优化RuO_(2)/D-Co_(3)O_(4)/CC催化剂暴露了更多的电化学活性位点,有效降低了催化反应对电解质中质子浓度的依赖性,从而触发了高性能的OER.只需要181 mV的过电位就能驱动10 mA cm^(-2)的电流密度,并能在此电流密度下保持连续电解120 h.RuO_(2)/D-Co_(3)O_(4)/CC是一种很有前途的酸性OER电催化剂.

Overexpressed Cyclin D1 and CDK4 proteins are responsible for the resistance to CDK4/6 inhibitor in breast cancer that can be reversed by PI3K/mTOR inhibitors

CDK4/6 inhibitors are the standard treatment in advanced HR+/HER2-breast cancer patients.Nevertheless,the resistance to CDK4/6 inhibitors is inevitable and the strategies to overcome resistance are of great interest.Here,we show that the palbociclibresistant breast cancer cells expressed significantly higher levels of Cyclin D1 and CDK4 proteins because of upregulated protein synthesis.Silencing Cyclin D1 or CDK4 led to cell cycle arrest while silencing Cyclin E1 or CDK2 restored the sensitivity to palbociclib.Furthermore,PI3K/mTOR pathway was hyper-activated in palbociclib-resistant cells,leading to more phosphorylated 4E-BP1 and higher levels of Cyclin D1 and CDK4 translation.Targeting PI3K/mTOR pathway with a specific PI3Kαinhibitor(BYL719)or an mTOR inhibitor(everolimus)reduced the protein levels of Cyclin D1 and CDK4,and restored the sensitivity to palbociclib.The tumor samples expressed significantly higher levels of Cyclin D1,CDK4,p-AKT and p-4E-BP1 after progression on palbociclib treatment.In conclusion,our findings suggest that overexpressed Cyclin D1 and CDK4 proteins lead to the resistance to CDK4/6 inhibitor and PI3K/mTOR inhibitors are able to restore the sensitivity to CDK4/6 inhibitors,which provides the biomarker and rationale for the combinational use of CDK4/6 inhibitors and PI3K/mTOR inhibitors after CDK4/6 inhibitor resistance in breast cancer.

Optimization of fixed aviation support resource station configuration for aircraft carrier based on aircraft dispatch mission scheduling

Before the dispatch of the carrier-based aircraft,a series of pre-flight preparation operations need to be completed on the flight deck.Flight deck fixed aviation support resource station configuration has an important impact on operation efficiency and sortie rate.However,the resource station configuration is determined during the aircraft carrier design phase and is rarely modified as required,which may not be suitable for some pre-flight preparation missions.In order to solve the above defects,the joint optimization of flight deck resource station configuration and aircraft carrier pre-flight preparation scheduling is studied in this paper,which is formulated as a two-tier optimization decision-making framework.An improved variable neighborhood search algorithm with four original neighborhood structures is presented.Dispatch mission experiment and algorithm performance comparison experiment are carried out in the computational experiment section.The correlation between the pre-flight preparation time(makespan)and flight deck cabin occupancy percentage is given,and advantages of the proposed algorithm in solving the mathematical model are verified.

Chinese expert consensus on the diagnosis and treatment of borderline developmental dysplasia of the hip (2022 Edition)

Developmental dysplasia of the hip(DDH)is one of the most common diseases causing hip pain in adults and is an important cause of osteoarthritis(OA).Borderline developmental dysplasia of the hip(BDDH)is a condition that falls between a normal hip and adult DDH.In BDDH,the lateral center-edge angle(LCEA)of the acetabulum is usually defined between 18°and 25°or 20°and 25°;however,this definition remains controversial.