Oxidation of 2,5‐bis(hydroxymethyl)furan to 2,5‐furandicarboxylic acid catalyzed by carbon nanotube‐supported Pd catalysts

The selective oxidation of 2,5‐bis(hydroxymethyl)furan(BHMF)in this work was proven as a promising route to produce 2,5‐furandicarboxylic acid(FDCA),an emerging bio‐based building‐block with wide application.Under ambient pressure,the modified carbon nanotube‐supported Pd‐based catalysts demonstrate the maximum FDCA yield of 93.0%with a full conversion of BHMF after 60 min at 60°C,much superior to that of the traditional route using 5‐hydroxymethylfurfural(HMF)as substrates(only a yield of 35.7%).The participation of PdH_(x) active species with metallic Pd can be responsible for the encouraging performance.Meanwhile,a possible reaction pathway proceeding through 2,5‐diformylfuran(DFF)and 5‐formyl‐2‐furancarboxylic acid(FFCA)as process intermediates is suggested for BHMF route.The present work may provide new opportunities to synthesize other high value‐added oxygenates by using BHMF as an alternative feedstock.

Influence of climate change on hydrological process in the upper reaches of Shiyang River:A case study of the Xiying River,China

Climate change is the dominant factor affecting the hydrological process, it is of great significance to simulate and predict its influence on water resources management, socio-economic activities, and sustainable development in the future. In this paper, the Xiying River Basin was taken as the study area, China Atmospheric Assimilation Driven Data Set(CMADS) and observation data from the Jiutiaoling station were used to simulate runoff of the SWAT model and calibrate and verify model parameters. On this basis, runoff change of the basin under the future climate scenario of CMIP6 was predicted. Our research shows that:(1) The contribution rates of climate change and human activities to runoff increase of the Xiying River are 89.17% and 10.83%, respectively. Climate change is the most important factor affecting runoff change of the Xiying River.(2) In these three different emission scenarios of SSP1-2.6, SSP2-4.5 and SSP5-8.5 in CMIP6 climate model, the average temperature increased by0.61, 1.09 and 1.74 C, respectively, in the Xiying River Basin from 2017 to 2050. Average precipitation increased by 14.36, 66.88, and 142.73 mm, respectively, and runoff increased by 15, 24, and 35 million m3, respectively.The effect of climate change on runoff will continue to deepen in the future.

柴达木盆地北缘砂岩型铀矿目标层地球物理特征与找矿预测

柴达木盆地北缘地处柴北缘坳陷构造带,区内砂岩型铀矿成矿条件优越,具有较大的铀成矿潜力。文章基于铀矿地质条件,综合利用测井、能谱测量、活性炭、可控源音频大地电磁方法(Controlled Source Audio Magnetotelluric,CSAMT),总结目标层岩石物性、区内放射性特征,且选择典型剖面进行CSAMT实测,针对柴北缘铀成矿环境地球物理特征进行研究分析,并进行找矿预测。研究结果表明:区内目的层上干柴沟组骨架砂体发育较好,泥-砂-泥三元结构反映清晰,岩石物性变化明显,目的层灰色还原砂体(细砂岩、粗砂岩)中铀背景值高;典型剖面特征显示,区内呈现高铀、高钍、低钾的放射性特征,而铀矿化所赋存的目标砂体一般呈中高阻特征。文章根据地质-地球物理响应特征推断,区内电性剖面上中高阻电性层和地表目的层放射性异常之间、铀异常带局部膨大部位为找矿的有利部位,为柴北缘砂岩型铀矿勘查提供重要技术参考。

激电中梯和测深在柳树湾金矿勘查中的应用研究

柳树湾金矿床位于汉南-碑坝元古代Fe-Cu成矿亚带内,为典型的黄铁矿化石英脉型金矿床。矿区前期的勘查仅限于地表圈定的矿化蚀变带周边的点对点找矿,对矿(化)体的延伸范围及垂向展布特征掌握不清,为进一步扩大矿体规模,加快找矿进度,选择了大功率激电测量对矿区进行勘查。通过激电中梯和测深方法在该矿床的应用研究表明:碑坝矿区内金矿体严格受NNE向或NS向断裂控制,呈脉状产出于断裂或岩性接触带部位,倾角较大。区内视极化率的ηs异常下限为5.00%,ηs值最高超过30.00%,电阻率值相对较低,表现为低阻高极化特征,激电异常多呈条带状展布,走向基本与构造走向一致。激电中梯及激电测深所圈定的IP1、IP2异常强度及规模都较好,且与地表已知矿化蚀变带对应性好,后经钻探查证,揭露了多层矿(化)石英脉体,脉体内赋存金矿(化)体,且与异常部位基本吻合,初步掌握了矿(化)体的发育位置和展布特征,取得了较好的地质找矿效果。认为该方法可以有效地指导钻探工作部署,是开展多金属矿勘查的重要技术手段之一,可作为该金矿床勘查的首选物探技术方法。

Strengthening effect of prefabrication(10-12)tensile twinning on AZ80+0.4%Ce magnesium alloy and inhibition mechanism of discontinuous precipitation

This paper provided an effective method to further improve the mechanical properties of the AZ80+0.4%Ce magnesium alloy wheel spoke.The effect of high strength and ductility was obtained with a yield strength of 295.36 MPa,an elongation of 10%,by the combination of pre-deformation(7%deformation)and two-stage aging treatment(120℃/9 h+175℃/24 h).The evolution of the microstructure and properties of the alloy was explored under the coupling conditions of different pre-deformation degrees and multi-stage aging.The results show that,pre-deformation introduced a large number of(1012)tensile twinning and dislocations,which greatly promoted the probability of continuous precipitates(CPs)appearing.On the contrary,the discontinuous precipitates(DPs)were limited by the vertical and horizontal twin structure.As a result,the pre-nucleation method of two-stage aging increased the proportion of CPs by 34%-38%.Owing to the DPs was effectively suppressed,the alloy's yield strength has been greatly improved.Besides,under multi-stage aging,the twin boundaries induce protruding nucleation to form static recrystallization by hindering the migration of dislocations,and the matrix swallows the twins,then the texture gradually tilts from the two poles to the basal plane.As an important supplement,the grain refinement and oblique texture promoted the improvement of the yield strength of the component.

Kármán vortex street in a spin–orbit-coupled Bose–Einstein condensate with PT symmetry

The dynamics of spin–orbit-coupled Bose–Einstein condensate with parity-time symmetry through a moving obstacle potential is simulated numerically. In the miscible two-component condensate, the formation of the Kármán vortex street is observed in one component, while ‘the half-quantum vortex street' is observed in the other component. Other patterns of vortex shedding, such as oblique vortex dipoles, V-shaped vortex pairs, irregular turbulence, and combined modes of various wakes, can also be found. The ratio of inter-vortex spacing in one row to the distance between vortex rows is approximately0.18, which is less than the stability condition 0.28 of classical fluid. The drag force acting on the obstacle potential is simulated. The parametric regions of Kármán vortex street and other vortex patterns are calculated. The range of Kármán vortex street is surrounded by the region of combined modes. In addition, spin–orbit coupling disrupts the symmetry of the system and the gain-loss affects the local particle distribution of the system, which leads to the local symmetry breaking of the system, and finally influences the stability of the Kármán vortex street. Finally, we propose an experimental protocol to realize the Kármán vortex street in a system.

Tunable spectral continuous shift of high-order harmonic generation in atoms by a plasmon-assisted shaping pulse

We delve into the phenomenon of high-order harmonic generation within a helium atom under the influence of a plasmon-assisted shaping pulse.Our findings reveal an intriguing manipulation of the frequency peak position in the harmonic emission by adjusting the absolute phase parameter within the frequency domain of the shaping pulse.This phenomenon holds potential significance for experimental setups necessitating precisely tuned single harmonics.Notably,we observe a modulated shift in the created harmonic photon energy,spanning an impressive range of 1.2 eV.This frequency peak shift is rooted in the asymmetry exhibited by the rising and falling edges of the laser pulse,directly influencing the position of the peak frequency emission.Our study quantifies the dependence of this tuning range and the asymmetry of the laser pulse,offering valuable insights into the underlying mechanisms driving this phenomenon.Furthermore,our investigation uncovers the emergence of semi-integer order harmonics as the phase parameter is altered.We attribute this discovery to the intricate interference between harmonics generated by the primary and secondary return cores.This observation introduces an innovative approach for generating semi-integer order harmonics,thus expanding our understanding of high-order harmonic generation.Ultimately,our work contributes to the broader comprehension of complex phenomena in laser-matter interactions and provides a foundation for harnessing these effects in various applications,particularly those involving precise spectral control and the generation of unique harmonic patterns.

蛋白酶体抑制剂RA190对口腔腺样囊性癌的调节作用

目的探讨蛋白酶体抑制剂双苄基吡啶酮(RA190)通过非ATP酶依赖性调节颗粒13(Rpn13)抑制泛素-蛋白酶体通路途径对口腔腺样囊性癌的作用,揭示RA190对腺样囊性癌ACC-2细胞增殖、凋亡的调节作用和可能机制。方法确定ACC-2细胞表达Rpn13后,选择RA190对ACC-2细胞的合适剂量(600 nmol/L);实验分为ACC-2组、ACC-2-Rpn13-siRNA组、RA190-ACC-2-Rpn13-siRNA组;敲除ACC-2细胞中Rpn13的表达;用RA190处理ACC-2细胞;用RA190处理敲除Rpn13的ACC-2细胞;MTT法观察各组细胞增殖、凋亡情况;Western blotting检测各组细胞Survivin、TIP30、泛素化蛋白相对表达量;qRT-PCR检测Survivin和TIP30 mRNA相对表达量。结果敲除Rpn13后的细胞组中Rpn13蛋白相对表达量较ACC-2细胞组降低(P<0.05)。MTT法检测显示,不同剂量的RA190作用ACC-2细胞后光密度(OD)比较,差异有统计学意义(P<0.05)。与ACC-2组比较,其余3组OD值均降低(P<0.05)。与ACC-2组比较,其余3组Survivin蛋白相对表达量均降低(P<0.05),TIP30蛋白相对表达量均升高(P<0.05),RA190-ACC-2组TIP30蛋白相对表达量最高,泛素化蛋白聚集最明显(P<0.05)。与ACC-2组比较,其余3组Survivin mRNA的相对表达量均降低(P<0.05),TIP30 mRNA相对表达量均升高(P<0.05)。结论RA190促凋亡的活动主要取决于Rpn13,Rpn13是口腔腺样囊性癌的致癌基因。RA190的调节作用可能改善口腔腺样囊性癌的预后,Rpn13可能成为治疗口腔腺样囊性癌的靶点。

微生物发酵在菜籽饼粕饲用品质改良中的应用研究进展

随着畜牧业的快速发展、优质饲料原料的严重不足以及国际进口贸易形势的日益紧张,开发非常规饲料资源的需求愈发迫切。菜籽饼粕是我国第一大油料作物油菜的加工副产物,饲用价值不高严重制约了在饲料工业中的应用。微生物发酵技术具有改良菜籽饼粕品质和提高畜禽生产性能的优势。本文综述了微生物发酵改良菜籽饼粕饲用价值的机理、影响因素以及微生物发酵菜籽饼粕饲料在畜禽生产中的应用,讨论了目前微生物发酵菜籽饼粕生产中存在的问题,展望了未来微生物发酵菜籽饼粕饲料的发展方向。

固体发酵技术在油料饼粕合成高附加值微生物代谢产物中的研究进展

随着加工技术的快速发展,油料饼粕简单直接的低值化应用已经无法满足产业的需求,如何将其合理转化为高附加值产品是当前社会亟需解决的问题。固体发酵技术由于具有高效、节能、环保等优势而备受关注。近年来,越来越多的研究者针对油料饼粕的特性,利用高通量筛选、代谢工程和人工诱变等方法获得了大量能够有效利用油料饼粕的微生物,以合成高附加值微生物代谢产物,如酶、抗生素、多不饱和脂肪酸、多肽等。本文综述了固体发酵技术在油料饼粕合成高附加值微生物代谢产物中的关键影响因素,包括微生物种类、油料饼粕种类和营养特性、发酵工艺、以及高附加值产物分类等,讨论了固体发酵技术在油料饼粕应用中存在的问题,为油料饼粕等一大类农业副产物的高值化转化提供了新的思路和展望。

杜仲叶及提取物在畜禽生产中的应用

杜仲叶作为一种可再生资源,对畜禽脂肪代谢、生产性能的改善等方面有积极作用,本文就杜仲叶及提取物的主要功能成分和在畜禽生产中的应用做一综述。

Influence of pore structures on the mechanical behavior of low-permeability sandstones:numerical reconstruction and analysis

The research of rock properties based on its inherent microscopic to mesoscopic porous structure has drawn great attention for its potential in predicting the macroscopic behavior of rocks.An accurate reconstruction of the threedimensional porous structure is a premise for the related studies of hydraulic and mechanical properties of rocks,such as the transport properties and mechanical responses under pressures.In this paper,we present a computer procedure for reconstructing the 3D porous structure of low-permeability sandstone.Two large-size 3D models are reconstructed based on the information of a reference model which is established from computed tomography(CT)images.A self-developed finite element method is applied to analyze the nonlinear mechanical behavior of the sandstone based on its reconstructed model and to compare the results with those based on the reference model.The good consistency of the obtained mechanical responses indicates the potential of using reconstruction models to predict the influences of porous structure on the mechanical properties of low-permeability sandstone.

Changes in sea ice kinematics in the Arctic outflow region and their associations with Arctic Northeast Passage accessibility

Amplification of climate warming in the Arctic is causing a dramatic retreat of sea ice, which means the Arctic sea routes are becoming increasingly accessible. This study used a satellite-derived sea ice motion product to quantify the kinematic features of sea ice in the Arctic outflow region which specially referred to the Fram Strait and to the north of the Northeast Passage(NEP). An observed trend of increased southward sea ice displacement from the central Arctic to the Fram Strait indicated enhancement of the Transpolar Drift Stream(TDS). In the regions to the north of the NEP, the long-term trend of northward sea ice speed in the Kara sector was +0.04 cm/s per year in spring. A significant statistical relationship was found between the NEP open period and the northward speed of the sea ice to the north of the NEP. The offshore advection of sea ice could account for the opening of sea routes by 33% and 15% in the Kara and Laptev sectors, respectively. The difference in sea level pressure across the TDS,i.e., the Central Arctic Index(CAI), presented more significant correlation than for the Arctic atmospheric Dipole Anomaly index with the open period of the NEP, and the CAI could explain the southward displacement of sea ice toward the Fram Strait by more than 45%. The impact from the summer positive CAI reinforces the thinning and mechanical weakening of the sea ice in the NEP region, which improves the navigability of the NEP.

The retromer component SNX6 interacts with dynactin p150Glued and mediates endosome-to-TGN transport

The retromer is a protein complex that mediates retrograde transport of transmembrane cargoes from endosomes to the trans-Golgi network （TGN）. It is comprised of a cargo-selection subcomplex of Vps26, Vps29 and Vps35 and a membrane-binding coat subcomplex of sorting nexins （SNXs）. Previous studies identified SNX1/2 as one of the components of the SNX subcomplex, and SNX5/6 as candidates for the second SNX. How the retromer-associated cargoes are recognized and transported by molecular motors are largely unknown. In this study, we found that one of SNX1/2＇s dimerization partners, SNX6, interacts with the p150Gued subunit of the dynein/dynactin motor complex. We present evidence that SNX6 is a component of the retromer, and that recruitment of the motor complex to the membrane-associated retromer requires the SNX6-pl50Gued interaction. Disruption of the SNX6-pl50Glued interaction causes failure in formation and detachment of the tubulovesicular sorting structures from endosomes and results in block of CI-MPR retrieval from endosomes to the TGN. These observations indicate that in addition to SNX1/2, SNX6 in association with the dynein/dynactin complex drives the formation and movement of tubular retrograde intermediates.

溃疡穿孔型Ⅵ型支气管结核患者经支气管镜氩气刀联合冷冻及异烟肼灌注治疗的疗效评价

目的评估经支气管镜氩气刀联合冷冻及异烟肼灌注治疗溃疡穿孔型Ⅵ型支气管结核(endobronchial tuberculosis,EBTB)患者的临床效果。方法搜集2013年1月至2018年8月湖南省胸科医院收治的符合纳入标准的65例溃疡穿孔型Ⅵ型EBTE患者的临床资料,将2017年1月之前收治的31例接受经支气管镜冷冻+异烟肼灌注治疗的患者作为对照组,将2017年1月至2018年8月前收治的34例接受经支气管镜氩气刀+冷冻+异烟肼灌注治疗的患者作为观察组。观察并分析两组患者痿口愈合时间、治疗效果及并发症情况。采用SPSS19.0软件进行数据的统计学分析,计量资料采用t检验或秩和检验,计数资料采用χ^2检验,均以F<0.05为差异有统计学意义。结果对照组和观察组患者分别进行经支气管镜介入治疗241例次和222例次,例均治疗次数分别为(7.81±2.20)次/例和(6.53±2.05)次/例,差异有统计学意义(r=2.425,P=0.018)。对照组行冷冻+异烟肼灌注治疗次数(3.45±0.91)次/例,高于观察组行氩气刀+冷冻+异烟肼灌注治疗(2.59±0.82)次/例(t=3.987,P<0.001)。对照组痿口愈合中位时间[12.0(10.0,12.0)周]长于观察组[10.0(8.0,12.0)周](Z=-2.001,P=0.045)。对照组和观察组患者治疗后痊愈和有效者分别为29例和33例、2例和1例,治疗有效率均为100.00%(χ^2=0.000,P=1.000)。两组患者在治疗过程中均未出现与治疗相关的支气管-纵隔痿、大出血或氮气刀相关气体栓塞等严重并发症。结论对溃疡穿孔型Ⅵ型EBTB行经支气管镜氩气刀联合冷冻及异烟肼灌注治疗,可减少治疗次数、缩短痿口愈合时间,安全有效,值得推广。

Comparisons of microstructure homogeneity,texture and mechanical properties of AZ80 magnesium alloy fabricated by annular channel angular extrusion and backward extrusion

This paper provided an efficient single pass severe plastic deformation(SPD)method,annular channel angular extrusion(ACAE),for fabricating AZ80 magnesium alloy shell part.The effect of ACAE process on the microstructure homogeneity,texture,and mechanical properties of extruded part was experimentally investigated.For comparison,conventional backward extrusion(BE)was also conducted on processing AZ80 part with same specification.The results showed that ACAE process has a better capacity to refine the microstructure and dramatic improve the deformation homogeneity of the extruded part than BE process.Due to two strong shear deformations were implemented,ACAE process could also concurrently modify the basal texture more notably than BE process.In particular,a bimodal texture was found in ACAE extruded part,which was greatly related to the enhanced synergetic action of basal slip and secondary<c+a>slip caused by the effective shear stress.More uniform and superior hardness along the thickness and height of part were achieved via ACAE process.Further surveying of tensile tests also showed that the part fabricated by ACAE process exhibited significantly higher and far more homogeneous tensile properties with an excellent balance of strength and ductility.The remarkable enhanced tensile properties of ACAE extruded part could be primarily attributed to the significant grain refinement,which provided a powerful grain boundary strengthening effect and meaningfully suppressed the development of twin-sized cracks during tensile deformation.It was established that ACAE process seemed to be a very promising single pass SPD method for manufacturing Mg-based alloy shell parts with more homogeneous microstructure and superior performance.

Ultrafine PdAg alloy nanoparticles anchored on NH2-functionalized 2D/2D TiO_(2) nanosheet/rGO composite as efficient and reusable catalyst for hydrogen release from additive-free formic acid at room temperature

A 2 D-2 D titanium dioxide nanosheet-reduced graphene oxide(TNS-r GO)composite with better electronic conductivity and hydrophilicity was prepared by the hydrothermal method.The as-obtained TNS-r GO composite was further functionalized with 3-aminopropyltriethoxysilane(APTES)to provide a large amount of-NH2 groups on the surface for anchoring ultrafine Pd Ag alloy nanoparticles with an average particle size of 1.69 nm by a facile wet reduction approach.Benefiting from the combined effects of well-dispersed Pd Ag alloy nanoparticles,facilitated electron transfer from TNS-r GO to Pd,and increased electron density of active sites,the Pd8 Ag_(1)/NH_(2)-TNS-r GO catalyst exhibited excellent activity towards dehydrogenation of formic acid without adding any additives at 298 K,corresponding to an initial turn over frequency as high as 1090 h-1,which is much higher than that of most other state-of-theart catalysts.

Recent research and development on forming for large magnesium alloy components with high mechanical properties

The lightweight of high-end equipment relies on high mechanical properties magnesium(Mg) alloy structural components, because it is the best way to improve equipment service performance and reduce energy consumption. This article summarizes the current progress and characteristics of large-scale high-performance Mg alloy components by analyzing the strengthening-toughening mechanisms, characteristics of plastic forming, and the preparation of large high mechanical properties forging blanks. Due to the lack of breakthroughs in the key technologies for forming large-scale Mg alloy components, their uniformity of mechanical properties and consistency are poor, the forming accuracy of components is low, and the production cost is high, which limit their engineering application and restrict the lightweight level of high-end equipment. In view of the above problems, the forming trends and research directions of large-scale and high mechanical properties Mg alloy components are proposed in this paper. It can provide help for the breakthrough of the key technology of large-scale Mg alloy components with high mechanical properties and expand the application of Mg alloy in high-end products.

Evolvement of tsunami waves on the continental shelves with gentle slope in the China Seas

Potential tsunami generated in the Okinawa Trench or the Manila Trench may attack the southeast coast of China. The continental shelves with extremely gentle slope in the China Seas affect the evolvement of tsunami waves. In this paper, we carry out the simulation of tsunami propagation based on the fully nonlinear and highly dispersive Boussinesq model, which could describe the nonlinearity and dispersion of water waves quite well. So the undulation characters could be well presented. In terms of the real topographies of the East China Sea and the South China Sea, we take some typical profiles to simulate the hypothetical tsunamis generated in the Okinawa Trench and the Manila Trench. Different waveforms in the near shore regions are obtained. The N-shape tsunami waves will evolve into long wave trains, undular bores or solitons near the coastal area. The numerical results of the near shore waveform provide essential conditions for the further studies of tsunami runup and inundation.

A Fast-Fractional Flow Reserve Simulation Method in A Patient with Coronary Stenosis Based on Resistance Boundary Conditions

Fractional flow reserve(FFR)is the gold standard to identify individual stenosis causing myocardial ischemia in catheter laboratory.The purpose of this study is to present a fast simulation method to estimate FFR value of a coronary artery,which can evaluate the performance of vascular stenosis,based on resistance boundary conditions.A patient-specific 3-dimensional(3D)model of the left coronary system with intermediate diameter stenosis was reconstructed based on the CTA images.The resistance boundary conditions used to simulate the coronary microcirculation were computed based on anatomical reconstruction of coronary 3D model.This study was performed by coupling the 3D coronary tree model with the lumped parameter model(0D model).The flow rate and pressure of coronary tree were calculated in twenty minutes.In addition,the effect of inlet pressure and myocardial mass on FFRss values has been investigated.The results showed that the effect of myocardial mass was greater than the effect of inlet pressure on FFRss.This FFRss simulation method can quickly and accurately assess the influence of coronary stenosis in aid clinical diagnosis.