实践创新能力驱动的化工人才培养模式构建与实施

以中北大学“化学工程与工艺”专业为例,构建“学训赛创”四元互促人才培养模式,在扎实的理论教学基础上,融入实验、实习、实训,并结合学科赛事,全面提升学生实践创新能力。实践结果表明,该模式强化了学生对复杂工程问题的处理能力,并显著提升了师资水平,为行业培养了工程创新人才,展现出良好的示范性和推广价值。

In situ forming injectable MSC-loaded GelMA hydrogels combined with PD for vascularized sweat gland regeneration

Dear Editor,Three dimensional(3D)bioprinted extracellular matrix(ECM)can be used to provide both biochemical and biophysical cues to direct mesenchymal stem cells(MSCs)differentiation,and then differentiated cells were isolated for implantation in vivo using surgical procedures.However,the reduced cell activity after cell isolation from 3D constructs and low cell retention in injured sites limit its application[1].Methacrylated gelatin(GelMA)hydrogel has the advantage of fast crosslinking,which could resemble complex architectures of tissue construct in vivo[2].Here,we adopted a noninvasive bioprinting procedure to imitate the regenerative microenvironment that could simultaneously direct the sweat gland(SG)and vascular differentiation from MSCs and ultimately promote the replacement of glandular tissue in situ(Fig.1a).

Three‑dimensional numerical simulation of dynamic strength and failure mode of a rock mass with cross joints

To study the dynamic mechanical properties and failure characteristics of intersecting jointed rock masses with different joint distributions under confining pressure,considering the cross angleαand joint persistence ratioη,a numerical model of the biaxial Hopkinson bar test system was established using the finite element method–discrete-element model coupling method.The validity of the model was verified by comparing and analyzing it in conjunction with laboratory test results.Dynamics-static combined impact tests were conducted on specimens under various conditions to investigate the strength characteristics and patterns of crack initiation and expansion.The study revealed the predominant factors influencing intersecting joints with different angles and penetrations under impact loading.The results show that the peak stress of the specimens decreases first and then increases with the increase of the cross angle.Whenα<60°,regardless of the value ofη,the dynamic stress of the specimens is controlled by the main joint.Whenα≥60°,the peak stress borne by the specimens decreases with increasingη.Whenα<60°,the initiation and propagation of cracks in the cross-jointed specimens are mainly controlled by the main joint,and the final failure surface of the specimens is composed of the main joint and wing cracks.Whenα≥60°orη≥0.67,the secondary joint guides the expansion of the wing cracks,and multiple failure surfaces composed of main and secondary joints,wing cracks,and co-planar cracks are formed.Increasing lateral confinement significantly increases the dynamic peak stress able to be borne by the specimens.Under triaxial conditions,the degree of failure of the intersecting jointed specimens is much lower than that under uniaxial and biaxial conditions.

Highly Porous Yet Transparent Mechanically Flexible Aerogels Realizing Solar-Thermal Regulatory Cooling

The demand for highly porous yet transparent aerogels with mechanical flexibility and solar-thermal dual-regulation for energy-saving windows is significant but challenging.Herein,a delaminated aerogel film(DAF)is fabricated through filtration-induced delaminated gelation and ambient drying.The delaminated gelation process involves the assembly of fluorinated cellulose nanofiber(FCNF)at the solid-liquid interface between the filter and the filtrate during filtration,resulting in the formation of lamellar FCNF hydrogels with strong intra-plane and weak interlayer hydrogen bonding.By exchanging the solvents from water to hexane,the hydrogen bonding in the FCNF hydrogel is further enhanced,enabling the formation of the DAF with intra-layer mesopores upon ambient drying.The resulting aerogel film is lightweight and ultra-flexible,which pos-sesses desirable properties of high visible-light transmittance(91.0%),low thermal conductivity(33 mW m^(-1) K^(-1)),and high atmospheric-window emissivity(90.1%).Furthermore,the DAF exhibits reduced surface energy and exceptional hydrophobicity due to the presence of fluorine-containing groups,enhancing its durability and UV resistance.Consequently,the DAF has demonstrated its potential as solar-thermal regulatory cooling window materials capable of simultaneously providing indoor lighting,thermal insulation,and daytime radiative cooling under direct sunlight.Significantly,the enclosed space protected by the DAF exhibits a temperature reduction of 2.6℃ compared to that shielded by conventional architectural glass.

Understanding Bridging Sites and Accelerating Quantum Efficiency for Photocatalytic CO_(2) Reduction

We report a novel double-shelled nanoboxes photocatalyst architecture with tailored interfaces that accelerate quantum efficiency for photocatalytic CO_(2) reduction reaction(CO_(2)RR)via Mo–S bridging bonds sites in S_(v)–In_(2)S_(3)@2H–MoTe_(2).The X-ray absorption near-edge structure shows that the formation of S_(v)–In_(2)S_(3)@2H–MoTe_(2) adjusts the coordination environment via interface engineering and forms Mo–S polarized sites at the interface.The interfacial dynamics and catalytic behavior are clearly revealed by ultrafast femtosecond transient absorption,time-resolved,and in situ diffuse reflectance–Infrared Fourier transform spectroscopy.A tunable electronic structure through steric interaction of Mo–S bridging bonds induces a 1.7-fold enhancement in S_(v)–In_(2)S_(3)@2H–MoTe_(2)(5)photogenerated carrier concentration relative to pristine S_(v)–In_(2)S_(3).Benefiting from lower carrier transport activation energy,an internal quantum efficiency of 94.01%at 380 nm was used for photocatalytic CO_(2)RR.This study proposes a new strategy to design photocatalyst through bridging sites to adjust the selectivity of photocatalytic CO_(2)RR.

Progress and prospects of pH-neutral aqueous organic redox flow batteries:Electrolytes and membranes

Aqueous organic redox flow batteries(AORFBs),which exploit the reversible electrochemical reactions of water-soluble organic electrolytes to store electricity,have emerged as an efficient electrochemical energy storage technology for the grid-scale integration of renewable electricity.pH-neutral AORFBs that feature high safety,low corrosivity,and environmental benignity are particularly promising,and their battery performance is significantly impacted by redox-active molecules and ion-exchange membranes(IEMs).Here,representative anolytes and catholytes engineered for use in pH-neutral AORFBs are outlined and summarized,as well as their side reactions that cause irreversible battery capacity fading.In addition,the recent achievements of IEMs for pH-neutral AORFBs are discussed,with a focus on the construction and tuning of ion transport channels.Finally,the critical challenges and potential research opportunities for developing practically relevant pH-neutral AORFBs are presented.

Decoding the inconsistency of six cropland maps in China

Accurate cropland information is critical for agricultural planning and production,especially in foodstressed countries like China.Although widely used medium-to-high-resolution satellite-based cropland maps have been developed from various remotely sensed data sources over the past few decades,considerable discrepancies exist among these products both in total area and in spatial distribution of croplands,impeding further applications of these datasets.The factors influencing their inconsistency are also unknown.In this study,we evaluated the consistency and accuracy of six cropland maps widely used in China in circa 2020,including three state-of-the-art 10-m products(i.e.,Google Dynamic World,ESRI Land Cover,and ESA WorldCover)and three 30-m ones(i.e.,GLC_FCS30,GlobeLand 30,and CLCD).We also investigated the effects of landscape fragmentation,climate,and agricultural management.Validation using a ground-truth sample revealed that the 10-m-resolution WorldCover provided the highest accuracy(92.3%).These maps collectively overestimated Chinese cropland area by up to 56%.Up to 37%of the land showed spatial inconsistency among the maps,concentrated mainly in mountainous regions and attributed to the varying accuracy of cropland maps,cropland fragmentation and management practices such as irrigation.Our work shed light on the promotion of future cropland mapping efforts,especially in highly inconsistent regions.

Physics-based battery SOC estimation methods:Recent advances and future perspectives

The reliable prediction of state of charge(SOC)is one of the vital functions of advanced battery management system(BMS),which has great significance towards safe operation of electric vehicles.By far,the empirical model-based and data-driven-based SOC estimation methods of lithium-ion batteries have been comprehensively discussed and reviewed in various literatures.However,few reviews involving SOC estimation focused on electrochemical mechanism,which gives physical explanations to SOC and becomes most attractive candidate for advanced BMS.For this reason,this paper comprehensively surveys on physics-based SOC algorithms applied in advanced BMS.First,the research progresses of physical SOC estimation methods for lithium-ion batteries are thoroughly discussed and corresponding evaluation criteria are carefully elaborated.Second,future perspectives of the current researches on physics-based battery SOC estimation are presented.The insights stated in this paper are expected to catalyze the development and application of the physics-based advanced BMS algorithms.

Correction to:Highly Porous Yet Transparent Mechanically Flexible Aerogels Realizing Solar-Thermal Regulatory Cooling

Tianxi Liu was missed to be denoted as a corresponding author in the article.Both Chao Zhang and Tianxi Liu are the corresponding authors of this article.The original article has been corrected.Open Access This article is licensed under a Creative Commons Attribution 4.0 International License,which permits use,sharing,adaptation,distribution,and reproduction in any medium or format,as long as you give appropriate credit to the original author(s)and the source,provide a link to the Creative Commons licence,and indicate if changes were made.The images or other third-party material in this article are included in the article’s Creative Commons licence,unless indicated otherwise in a credit line to the material.If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use,you will need to obtain permission directly from the copyright holder.

Measuring small longitudinal phase shifts via weak measurement amplification

Weak measurement amplification,which is considered as a very promising scheme in precision measurement,has been applied to various small physical quantities estimations.Since many physical quantities can be converted into phase signals,it is interesting and important to consider measuring small longitudinal phase shifts by using weak measurement.Here,we propose and experimentally demonstrate a novel weak measurement amplification-based small longitudinal phase estimation,which is suitable for polarization interferometry.We realize one order of magnitude amplification measurement of a small phase signal directly introduced by a liquid crystal variable retarder and show that it is robust to the imperfection of interference.Besides,we analyze the effect of magnification error which is never considered in the previous works,and find the constraint on the magnification.Our results may find important applications in high-precision measurements,e.g.,gravitational wave detection.

Dinitrophenyl-oxadiazole compounds:Design strategy,synthesis,and properties of a series of new melt-cast explosives

Melt-cast explosives are the most widely used energetic materials in military composite explosives,researchers have been unremittingly exploring high-energy and insensitive melt-cast explosives.In this work,a series of dinitrophenyl-oxadiazole compounds were designed and prepared.These compounds have an ideal low melting point(80-97℃),good detonation performance(detonation velocity D=6455-6971 m/s,detonation pressure P=18-19 GPa)and extreme insensitive nature(impact sensitivity≥60 J,friction sensitivity>360 N).All these compounds were well characterized by nuclear magnetic resonance,fourier transform infrared spectroscopy,elemental analysis.Compounds 2,3 were unambiguously confirmed by X-ray single crystal diffraction analysis.As a result,their overall properties are superior to traditional melt-cast explosives trinitrotoluene(TNT)and dinitroanisole(DNAN)which may have excellent potential applications in insensitive melt-cast explosives.

Preoperatively predicting vessels encapsulating tumor clusters in hepatocellular carcinoma:Machine learning model based on contrast-enhanced computed tomography

BACKGROUND Recently,vessels encapsulating tumor clusters(VETC)was considered as a distinct pattern of tumor vascularization which can primarily facilitate the entry of the whole tumor cluster into the bloodstream in an invasion independent manner,and was regarded as an independent risk factor for poor prognosis in hepatocellular carcinoma(HCC).AIM To develop and validate a preoperative nomogram using contrast-enhanced computed tomography(CECT)to predict the presence of VETC+in HCC.METHODS We retrospectively evaluated 190 patients with pathologically confirmed HCC who underwent CECT scanning and immunochemical staining for cluster of differentiation 34 at two medical centers.Radiomics analysis was conducted on intratumoral and peritumoral regions in the portal vein phase.Radiomics features,essential for identifying VETC+HCC,were extracted and utilized to develop a radiomics model using machine learning algorithms in the training set.The model’s performance was validated on two separate test sets.Receiver operating characteristic(ROC)analysis was employed to compare the identified performance of three models in predicting the VETC status of HCC on both training and test sets.The most predictive model was then used to constructed a radiomics nomogram that integrated the independent clinical-radiological features.ROC and decision curve analysis were used to assess the performance characteristics of the clinical-radiological features,the radiomics features and the radiomics nomogram.RESULTS The study included 190 individuals from two independent centers,with the majority being male(81%)and a median age of 57 years(interquartile range:51-66).The area under the curve(AUC)for the combined radiomics features selected from the intratumoral and peritumoral areas were 0.825,0.788,and 0.680 in the training set and the two test sets.A total of 13 features were selected to construct the Rad-score.The nomogram,combining clinicalradiological and combined radiomics features could accurately predict VETC+in all three sets,with AUC values of 0.859,0.848 and 0.757.Decision curve analysis revealed that the radiomics nomogram was more clinically useful than both the clinical-radiological feature and the combined radiomics models.CONCLUSION This study demonstrates the potential utility of a CECT-based radiomics nomogram,incorporating clinicalradiological features and combined radiomics features,in the identification of VETC+HCC.

探测来自宇宙深空的奥秘

敦煌,这个承载着千年历史与文化的地方,不仅是丝绸之路的重要驿站,更是人类向往天外的神思的象征。那壁画上的飞天,仿佛诉说着古人对天空的无限遐想与追求,给人带来无尽的美的享受。而更为神奇的是,敦煌壁画上还隐藏着一幅古老的星图,它绘制了多达1359颗恒星,这在那时是一个惊人的数字。要知道,在欧洲人发明望远镜之前,所记录的恒星数量从未超过1022颗。因此,敦煌星图不仅代表着中国古代天文学的卓越成就,更彰显了人类对宇宙的无尽好奇与探索精神。

万里敦煌道 引领射电波——记超大型中微子射电探测阵列实验(GRAND)发展过程

2019年的春天,万里敦煌道,三春雪未晴。月牙湖畔,莫高窟旁,千年古丝绸之路上,一群不同肤色和面孔的物理学家相聚一堂,瞄准射电探测中微子实验进行了数天的会议。随后他们驾车穿越薄雪覆盖的祁连山脉,深入戈壁,到达青海冷湖地区,在方圆几百里内勘探环境。这里渺无人烟,几乎没有人类活动的痕迹,被誉为地球上最像火星的地区。青藏高原绵延千里,在这里由西南往东北海拔逐渐降低。高耸的昆仑山脉和阿尔金山脉在这里和祁连山脉相对,将柴达木盆地环抱其中。正是这样的环境,将这些人吸引到这里。

星蒌承气汤对急性缺血性中风小鼠中枢和外周免疫炎症的影响与肠道菌群有关

目的:探讨星蒌承气汤(Xinglou Chengqi decoction,XCD)对急性缺血性卒中小鼠脑–肠轴的影响。方法:根据中医辨证分型标准,采用改良Longa法建立痰热腑实证脑缺血再灌注模型。60只无特定病原体的雄性C57BL/6小鼠随机分为5组,36只经抗生素处理的(ABX)小鼠随机分为三组。采用酶联免疫吸附试验检测盲肠去甲肾上腺素(NE)和胃动素(MTL),免疫组织化学方法检测盲肠酪氨酸羟化酶(TH)蛋白表达水平,免疫荧光法检测Iba-1和胶质纤维酸性蛋白(GFAP)表达水平,流式多因子技术检测血清炎症因子含量。结果:与假手术组相比,大脑中动脉闭塞(MCAO)组盲肠组织中TH的表达水平显著升高(P=0.015)。与假手术组相比,MCAO组大鼠MTL水平显著升高(P<0.001),与MCAO组相比XCD组和尼莫地平(Nim)组大鼠血清MTL水平明显降低(P=0.003和P=0.007)。MCAO组星形胶质细胞和小胶质细胞明显激活,而XCD组激活程度低于MCAO组。ABX小鼠中星形胶质细胞和小胶质细胞在ABX–MCAO组明显激活,而ABX–XCD组激活程度较低。ABX–XCD组白细胞介素22水平较ABX–MCAO组显著升高(P=0.021)。结论:星蒌承气汤对急性缺血性卒中小鼠脑–肠轴的免疫通路有明显的调节作用,去除肠道菌群使该作用明显减弱。

Intelligent prediction of slope stability based on visual exploratory data analysis of 77 in situ cases

Slope stability prediction research is a complex non-linear system problem.In carrying out slope stability prediction work,it often encounters low accuracy of prediction models and blind data preprocessing.Based on 77 field cases,5 quantitative indicators are selected to improve the accuracy of prediction models for slope stability.These indicators include slope angle,slope height,internal friction angle,cohesion and unit weight of rock and soil.Potential data aggregation in the prediction of slope stability is analyzed and visualized based on Six-dimension reduction methods,namely principal components analysis(PCA),Kernel PCA,factor analysis(FA),independent component analysis(ICA),non-negative matrix factorization(NMF)and t-SNE(stochastic neighbor embedding).Combined with classic machine learning methods,7 prediction models for slope stability are established and their reliabilities are examined by random cross validation.Besides,the significance of each indicator in the prediction of slope stability is discussed using the coefficient of variation method.The research results show that dimension reduction is unnecessary for the data processing of prediction models established in this paper of slope stability.Random forest(RF),support vector machine(SVM)and k-nearest neighbour(KNN)achieve the best prediction accuracy,which is higher than 90%.The decision tree(DT)has better accuracy which is 86%.The most important factor influencing slope stability is slope height,while unit weight of rock and soil is the least significant.RF and SVM models have the best accuracy and superiority in slope stability prediction.The results provide a new approach toward slope stability prediction in geotechnical engineering.

经皮肝穿刺胆道引流/胆道支架植入术治疗肝外胆管癌合并梗阻性黄疸的研究进展

肝外胆管癌(extrahepatic cholangiocarcinoma,ECC)是起源于肝外胆管包括肝门区至胆总管下端胆管的恶性肿瘤,确诊时胆道受侵犯压迫常合并出现梗阻性黄疸,患者多处于中晚期而丧失根治性切除机会.随着介入技术及医学材料的发展,经皮肝穿刺胆道引流术(percutaneous transhepatic cholangial drainage,PTCD)或胆道支架植入术(percutaneous transhepatic biliary stent,PTBS)已成为解除胆道梗阻的主要治疗方法.然而,术后并发症的发生严重影响患者的预后,目前发现胆道支架联合局部治疗可显著延长胆道通畅时间.本文综述关于PTCD/PTBS治疗肝外胆管癌合并梗阻性黄疸的进展,评价其临床疗效,并指出目前存在的问题及处理方法,为后续相关研究提供更多参考.

An optimization method for enhancement of gas–liquid mass transfer in a bubble column reactor based on the entropy generation extremum principle

In this study,an optimization method is proposed to enhance the gas–liquid mass transfer in bubble column reactor based on the entropy generation extremum principle.The mass transfer–induced entropy generation can be maximized with the increase of mass transfer rate,based on which the velocity field can be optimized.The oxygen gas–liquid mass transfer is the major rate–limiting step of the toluene emissions biodegradation process in bubble column reactor,so the entropy generation due to oxygen mass transfer is used as the objective function,and the conservation equations of the gas–liquid flow and species concentration are taken as constraints.This optimization problem is solved by the calculus of variations,the optimal liquid flow pattern is obtained and the relationship of the maximum mass transfer enhancement on viscous dissipation is revealed,which can be used to improve the design of internal structure of the bubble column reactor.

Causes of the record-low Antarctic sea-ice in austral summer 2022

2022年夏季(2021年12月至2022年2月)南极海冰面积达到历史新低,西南极减少最显著.2021年8~10月南半球环状模接近历史最强和7~9月海洋性大陆附近海温显著增暖是两个关键因素.由于平流层臭氧破纪录减少使得前者维持历史最强或接近最强,导致阿蒙森低压(ASL)加深并向西南移动,有利于海冰减少.后者持续到夏季,有利于拉尼娜的发展,通过激发罗斯贝波列加深ASL.在热力上,臭氧减少导致向下净短波辐射增加,引起西南极增暖.此外,净短波辐射-海温-云形成正反馈,与埃克曼输送一起,放大表面增暖,从而促进海冰融化.

High-quality haplotype-resolved genome assembly of cultivated octoploid strawberry

Cultivated strawberry(Fragaria×ananassa),a perennial herb belonging to the family Rosaceae,is a complex octoploid with high heterozygosity at most loci.However,there is no research on the haplotype of the octoploid strawberry genome.Here we aimed to obtain a high-quality genome of the cultivated strawberry cultivar,“Yanli”,using single molecule real-time sequencing and high-throughput chromosome conformation capture technology.The“Yanli”genome was 823 Mb in size,with a long terminal repeat assembly index of 14.99.The genome was phased into two haplotypes,Hap1(825 Mb with contig N50 of 26.70 Mb)and Hap2(808 Mb with contig N50 of 27.51 Mb).Using the combination of Hap1 and Hap2,we obtained for the first time a haplotype-resolved genome with 56 chromosomes for the cultivated octoploid strawberry.We identified a∼10 Mb inversion and translocation on chromosome 2-1.104957 and 102356 protein-coding genes were annotated in Hap1 and Hap2,respectively.Analysis of the genes related to the anthocyanin biosynthesis pathway revealed the structural diversity and complexity in the expression of the alleles in the octoploid F.×ananassa genome.In summary,we obtained a high-quality haplotype-resolved genome assembly of F.×ananassa,which will provide the foundation for investigating gene function and evolution of the genome of cultivated octoploid strawberry.