Recent Research Progress of Paper-Based Supercapacitors Based on Cellulose

In recent years,paper-based functional materials have received extensive attention in the field of energy storage due to their advantages of rich and adjustable porous network structure and good flexibility.As an important energy storage device,paper-based supercapacitors have important application prospects in many fields and have also received extensive attention from researchers in recent years.At present,researchers have modified and regulated paper-based materials by different means such as structural design and material composition to enhance their electrochemical storage capacity.The development of paper-based supercapacitors provides an important direction for the development of green and sustainable energy.Therefore,it is of great significance to summarize the relevant work of paper-based supercapacitors for their rapid development and application.In this review,the recent research progress of paper-based supercapacitors based on cellulose was summarized in terms of various cellulose-based composites,preparation skills,and electrochemical performance.Finally,some opinions on the problems in the development of this field and the future development trend were proposed.It is hoped that this review can provide valuable references and ideas for the rapid development of paper-based energy storage devices.

Rapid fabrication of modular 3D paper-basedmicrofluidic chips using projection-based 3D printing

Paper-based microchips have different advantages,such as better biocompatibility,simple production,and easy handling,making them promising candidates for clinical diagnosis and other fields.This study describes amethod developed to fabricate modular three-dimensional(3D)paper-based microfluidic chips based on projection-based 3D printing(PBP)technology.A series of two-dimensional(2D)paper-based microfluidic modules was designed and fabricated.After evaluating the effect of exposure time on the accuracy of the flow channel,the resolution of this channel was experimentally analyzed.Furthermore,several 3D paper-based microfluidic chips were assembled based on the 2D ones using different methods,with good channel connectivity.Scaffold-based 2D and hydrogel-based 3D cell culture systems based on 3D paper-based microfluidic chips were verified to be feasible.Furthermore,by combining extrusion 3D bioprinting technology and the proposed 3D paper-based microfluidic chips,multiorgan microfluidic chips were established by directly printing 3D hydrogel structures on 3D paperbased microfluidic chips,confirming that the prepared modular 3D paper-based microfluidic chip is potentially applicable in various biomedical applications.

Fiber swelling to improve cycle performance of paper-based separator for lithium-ion batteries application

It is well established that paper-based separators display short-circuit risk in lithium-ion batteries due to their intrinsic micron-sized pores.In this research,we have adjusted pore structure of paper by fiber swelling in liquid electrolyte.Specifically,the paper-based separator is prepared by propionylated sisal fibers through a wet papermaking process.Scanning electron microscope(SEM)and multi-range X-ray nano-computed tomography(CT)images display strong swelling of modified fibers after electrolyte absorption,which can effectively decrease the pore size of separator.Due to the high electrolyte uptake(817 wt%),paper-based separator exhibits ionic conductivity of 2.93 mS cm^(-1).^(7)Li solid-state NMR spectroscopy and Gaussian simulation reveal that the formation of local high Li^(+)ion concentration in the separator and its low absorption energy with Li^(+) ion(62.2 kcal mol^(-1))is conducive to the ionic transportation.In particular,the assembled Li/separator/LiFePO_(4) cell displays wide electrochemical stability window(5.2 V)and excellent cycle performance(capacity retention of 96.6%after 100 cycles at 0.5C)due to the reduced side reactions as well as enhanced electrolyte absorption and retention capacity by propionylation.Our proposed strategy will provide a novel perspective to design high-performance biobased separators to boost the development of clean and sustainable energy economy.

大规模英语口语考试评分质量保障体系建设——以CET-SET6在线评分为例

大规模外语口语考试在线评分质量体系建设是一项系统工程,也是保障评分信度和可靠性的关键环节。在全国大学英语四、六级考试(CET)在线评分流程顶层设计指导下,三维度在线评分质量保障体系将口语评分过程中样卷及培训卷挑选流程、评分员培训流程、评分过程动态监控流程三个不同层面的子系统一环扣一环关联起来,使标准化工作机制一步一步落到实处。该体系从宏观和微观的管理视角,自上而下而又自下而上地从不同层面对评分误差进行控制,以降低评分中因评分员主观因素造成的给分差异。CET-SET6在线评分实践表明,该保障体系的实施提升了CET-SET评分信度和效度,有效保障了评分质量。该体系的建设也可为提高大规模、高风险考试在线评分信度、效度及质量管理水平提供一定的借鉴和参考。

In Situ Directional Polymerization of Poly(1,3-dioxolane)Solid Electrolyte Induced by Cellulose Paper-Based Composite Separator for Lithium Metal Batteries

In traditional in situ polymerization preparation for solid-state electrolytes,initiators are directly added to the liquid precursor.In this article,a novel cellulose paper-based composite separator is fabricated,which employs alumina as the inorganic reinforcing material and is loaded with polymerization initiator aluminum trifluoromethanesulfonate.Based upon this,a separator-induced in situ directional polymerization technique is demonstrated,and the extra addition of initiators into liquid precursors is no longer required.The polymerization starts from the surface and interior of the separator and extends outward with the gradually dissolving of initiators into the precursor.Compared with its traditional counterpart,the separator-induced poly(1,3-dioxolane)electrolyte shows improved interfacial contact as well as appropriately mitigated polymerization rate,which are conducive to practical applications.Electrochemical measurement results show that the prepared poly(1,3-dioxolane)solid electrolyte possesses an oxidation potential up to 4.4 V and a high Li+transference number of 0.72.After 1000 cycles at 2 C rate(340 mA g^(−1)),the assembled Li||LiFePO_(4)solid battery possesses a 106.8 mAh g^(−1)discharge capacity retention and 83.5%capacity retention ratio,with high average Coulombic efficiency of 99.5%achieved.Our work may provide new ideas for the design and application of in situ polymerization technique for solid electrolytes and solid batteries.

Analysis of Non-English Major College Students’Test Anxiety in CET-4

Test anxiety, which means individuals show excessive worry, nervousness and anxiety in examination contexts, is becoming a more and more common phenomenon. A moderate level of test anxiety will motivate students while a too high or too low level of test anxiety will influence students’ academic performance and their cognitive abilities. Most present researches are focused on secondary school students or on the final exam of a specific school. Few researches on college students and standard tests can be found. Therefore, the researcher took 255 college students as samples to investigate the test anxiety level of non-English majors, their attitudes towards different test tasks (ATDTT) and the correlation between them. The results of the research are as follows: Firstly, the students from non-English majors are at the lower of a moderate test anxiety level in CET-4 and there is no significant gender difference. Secondly, among the four sections in CET-4, students are most positive in writing, less positive in translation and reading, and the least positive in listening. Thirdly, students’ ATDTT in CET-4 are negatively correlated with total test anxiety, cognitive anxiety and emotional anxiety. The researcher hopes this research can offer some help to teachers and students in need.

大学英语教学中翻译写作教学模式的有效性——基于CET翻译题成绩的初步实验研究

当前,大学英语四、六级考试汉译英主题倾向于中国文化相关,成为应考难点之一。将翻译写作教学模式运用至大学英语教学,特别是针对CET翻译题型的教学,或能有效应对这一难点。根据一项于独立学院选取非英语专业英语水平相近的两个自然班展开的初步对比实验研究发现,对比实验B班,实验A班采纳翻译写作教学模式,通过句法分析训练、写作与背诵训练、中英语序转换训练、拆句与组句训练,一定程度上消除了应考畏难感,CET4模考成绩较有明显提高,翻译能力有所提升。这一研究结果对大学英语翻译与写作教学均有一定指导意义,扩展了翻译写作学理论的应用范围与研究视野。

A MXene-functionalized paper-based electrochemical immunosensor for label-free detection of cardiac troponin I

Convenient,rapid,and accurate detection of cardiac troponin I(cTnI)is crucial in early diagnosis of acute myocardial infarction(AMI).A paper-based electrochemical immunosensor is a promising choice in this field,because of the flexibility,porosity,and cost-efficacy of the paper.However,paper is poor in electronic conductivity and surface functionality.Herein,we report a paper-based electrochemical immunosensor for the label-free detection of cTnI with the working electrode modified by MXene(Ti_(3)C_(2))nanosheets.In order to immobilize the bio-receptor(anti-cTnI)on the MXene-modified working electrode,the MXene nanosheets were functionalized by aminosilane,and the functionalized MXene was immobilized onto the surface of the working electrode through Nafion.The large surface area of the MXene nanosheets facilitates the immobilization of antibodies,and the excellent conductivity facilitates the electron transfer between the electrochemical species and the underlying electrode surface.As a result,the paper-based immunosensor could detect cTnI within a wide range of 5-100 ng/mL with a detection limit of 0.58 ng/mL.The immunosensor also shows outstanding selectivity and good repeatability.Our MXene-modified paper-based electrochemical immunosensor enables fast and sensitive detection of cTnI,which may be used in real-time and cost-efficient monitoring of AMI diseases in clinics.

Fabrication of paper-based devices for in vitro tissue modeling

Paper devices have recently attracted considerable attention as a class of cost-effective cell culture substrates for various biomedical applications.The paper biomaterial can be used to partially mimic the in vivo cell microenvironments mainly due to its natural three-dimensional characteristic.The paper-based devices provide precise control over their structures as well as cell distributions,allowing recapitulation of certain interactions between the cells and the extracellular matrix.These features have shown great potential for the development of normal and diseased human tissue models.In this review,we discuss the fabrication of paper-based devices for in vitro tissue modeling,as well as the applications of these devices toward drug screening and personalized medicine.It is believed that paper as a biomaterial will play an essential role in the field of tissue model engineering due to its unique performances,such as good biocompatibility,eco-friendliness,cost-effectiveness,and amenability to various biodesign and manufacturing needs.

Facile Fabrication of Cellulosic Paper-based Composites with Temperature-controlled Hydrophobicity and Excellent Mechanical Strength

In this paper,we presented a novel strategy to employ a plantderived carbohydrate polymer,i.e.,cellulose,to prepare a hydrophobic composite.Cellulose was used as a scaffold,and ethylene-propylene side by side(ES)fiber was thermally melted and then coated on the cellulose surface to achieve hydrophobicity.Experimental results revealed that the thermocoating ES fibers greatly increased the water contact angle of the cellulose scaffold from 25°to 153°while simultaneously enhanced the wet tensile strength of the composite approximately 6.7-fold(drying temperature of 170℃)compared with the pure cellulose paper.In particular,compared with other related research,the prepared cellulose-based composite possessed excellent hydrophobicity and superior mechanical strength,which introduces a new chemical engineering approach to prepare hydrophobic cellulose-based functional materials.

Highly Improved Microstructure and Properties of Poly(p-phenylene terephthalamide) Paper-based Materials via Hot Calendering Process

In this study,the effect of hot calendering process on the microstructure and properties of poly(p-phenylene terephthalamide)(PPTA) paper-based materials was investigated.The microstructures of the fracture surface,crystalline structure,and single fiber strength of the PPTA paperbased materials as well as the different bonding behaviors between the PPTA fibers and PPTA fibrids obtained before and after the hot calendering process were examined.The results indicated that a high linear pressure would result in a limited improvement of the strength owing to the unimproved paper structure.The optimal values of tensile index and dielectric strength of 56.6 N·m/g and 27.6 kV/mm,respectively,could only be achieved with a synergistic effects of hot calendering temperature and linear pressure(240℃ and 110 k N/m,respectively).This result suggested it was possible to achieve a significant reinforcement and improvement in the interfacial bonding of functional PPTA paper-based materials,and avoid the formation of unexpected pleats and cracks in PPTA paper-based materials during the hot calendering process.

Determination of inhibitory activity of Salvia miltiorrhiza extracts on xanthine oxidase with a paper-based analytical device

A novel paper-based analytical device(PAD)was prepared and applied to determine the xanthine oxidase(XOD)inhibitory activity of Salvia miltiorrhiza extracts(SME).First,polycaprolactone was 3D printed on filter paper and heated to form hydrophobic barriers.Then the modified paper was cut according to the specific design.Necessary reagents including XOD for the colorimetric assay were immobilized on two separate pieces of paper.By simply adding phosphate buffer,the reaction was performed on the double-layer PAD.Quantitative results were obtained by analyzing the color intensity with the specialized device system(consisting of a smartphone,a detection box and sandwich plates).The 3Dprinted detection box was small,with a size of 9.0 cm×7.0 cm×11.5 cm.Color component G performed well in terms of linearity and detection limits and thus was identified as the index.The reaction conditions were optimized using a definitive screening design.Moreover,a 10%glycerol solution was found to be a suitable stabilizer.When the stabilizer was added,the activity of XOD could be maintained for at least 15 days under 4℃ or-20℃ storage conditions.The inhibitory activity of SME was investigated and compared to that of allopurinol.The results obtained with the PAD showed agreement with those obtained with the microplate method.In conclusion,the proposed PAD method is simple,accurate and has a potential for point-of-care testing.It also holds promise for use in rapid quality testing of medicinal herbs,intermediate products,and preparations of traditional Chinese medicines.

A flow chemiluminescence paper-based microfuidic device for detection of chromium(Ⅲ)in water

In this work,a solely gravity and capillary force-driven flow chemiluminescence(GCF-CL)paper-based microfuidic device has been proved for the first time as a new platforn for inex-pensive,usable,mini mally instrumented dynamic chemiluninescence(CL)detection of chromium(Ⅲ)[Cr(Ⅲ)],where an appropriate angle of inclination between the loading and detection zones on the paper produces a rapid flow of CL prompt solution through the paper charnel.For this study,we use a cost-effective paper device that is manufactured by a simple wax screen-printing method,while the signal generated from the Cr(Ⅲ)-catalyzed oxidation of luminol by H_(2)O_(2) is recorded by a low-cost and luggable CCD camera.A series of GCF-CL affecting factors have been evaluated carefully.At optimal conditions,two linear relationships between GCF-CL intensities and the logarithms of Cr(Ⅲ)concentrations are obtained in the concentration mnges of 0.025-35 mg/L and 50-500 mg/L separately,with the detection limit of 0.0245mg/L for a les than 30s assay,and relative standard deviations(RSDs)of 38%,4.5%and 2.3%for 0.75,5 and 50 mg/L of Cr(Ⅲ)(n=8).The above results indicate that the GCF-CL paper-based microfluidic device possesses a receivable sensitivity,dynamic range,storage stability and reproducibility.Finally,the developed GCF-CL is utilized for Cr(Ⅲ)detection in real water samples.

Literature Review of the Use of Zinc and Zinc Compounds in Paper-Based Microfluidic Devices

Zinc and its compounds, alloys and composites play an important role in the modern day world and find application in almost every aspect that can improve the quality of our lives. This ranges from supplements and pharmaceuticals that are meant to improve our health and wellbeing to additives meant to guard or reduce corrosion in metals. However, over the past several years, a new area of technology has been garnering a great deal of attention and has made use of zinc and its compounds. This is with reference to paper-based microfluidic technology that offers several advantages and that keeps expanding in the amount of applications it covers. In this paper, a review is offered for the applications that have used zinc or zinc compounds in paper-based microfluidic devices.

Flexible Paper-Based Li-ion Batteries: A Review

Lithium-ion (Li-ion) batteries have been fabricated in various ways to improve flexibility. Flexibility could be enhanced via active materials, separators, electrodes, and electrolytes, which could then be integrated to form flexible electronic devices with promising electrochemical properties compared to traditional non-flexible Li-ion batteries. Recent progress towards flexible Li- ion batteries fabrication, materials, and their electrochemical properties are investigated in this review. Additionally, recent developments in electronic devices utilizing flexible batteries and their future applications are explored. Portable and wearable electronics, as the primary beneficiaries of the flexible, rechargeable, and high-performance Li-ion batteries, are examined. In the end, various applications and challenges of flexible batteries in healthcare and various energy storage systems, considering practical implementation, are argued.

改进的C4.5算法在CET-4成绩分析中的应用

CET-4是一个客观、准确的大学生英语能力测量平台,C4.5算法在应用于CET-4成绩分析中仍存在一些问题。针对运用C4.5算法对高职院校CET-4成绩数据构建分析决策树时存在的离散化运算繁琐、忽视各属性影响度等典型问题,提出一种面向高职院校CET-4成绩分析的改进C4.5算法。首先通过在C4.5算法中引入成绩正态分布规律确立初始聚类中心、K-means算法来离散连续属性;其次引入CET-4中听、读、写的权重来修正信息增益率的计算;最后运用改进的C4.5算法、经典的C4.5算法分别构建决策树模型并进行预测分析。实验结果表明,改进的C4.5算法所构建高职院校CET-4成绩分析的模型效率、预测能力均有明显提高。运用改进的C4.5算法有效地分析出影响CET-4达标各因素间的关系,从而提升CET-4反拨英语教学效应。

First Detailed Photometric Investigation on the Nature of Contact Binary System AA Cet

The TESS light curve(LC)of the marginal contact binary A A Cet was analyzed simultaneously with the radial velocity and the orbital period(OP)change of the system was investigated.The physical parameters of the system were obtained by analyzing the LC of A A Cet with the Wilson-Devinney method,and the absolute parameters of the components were calculated using the results obtained.For the components of AA Cet,the masses and radii were calculated as M_(1)=1.39±0.04 M_⊙,M_(2)=0.48±0.02 M_⊙,and R_(1)=1.64±0.03 R_⊙,R_(2)=1.01±0.04 R_⊙,respectively.AA Cet is a marginal contact binary with a temperature difference of 1305 K between its components.A total of 14 eclipse times were obtained from the TESS data and used in the OP analysis together with those collected from the literature.It has been observed that the change in the OP of AA Cet is in the form of a decreasing parabola.Conservative mass transfer between the components has been interpreted as the reason for this change.The OP decrease amount of A A Cet was obtained as dP/dt=0.0062±0.0006 s yr^(-1).and the reason for this decrease was attributed to a 3.3(9)×10^(-8)M_⊙.mass transfer per year from the more massive component to the less massive one.The age of A A Cet has been estimated as 7 Gyr,as the age of contact systems helps us to understand their evolution.

美国国家科学技术委员会更新《关键和新兴技术清单》(2024年版)

2024年2月,美国国家科学技术委员会(NSTC)发布了新一版关键和新兴技术(critical and emerging technologies,CETs)清单。NSTC以美国2020年发布的《关键和新兴技术国家战略》为基础,每两年更新一次关键和新兴技术领域列表及各领域内的具体技术清单。跟2022年版本相比,2024年版CETs清单中,“清洁能源发电和存储技术”替代了“可再生能源发电和存储技术”的说法,排名第八.

CET-SET复杂考试环境下录音质量保障与检测方法研究

当前全国大学英语四、六级口语考试(CET-SET)全面采用计算机录音、人工评分或计算机智能辅助的方式进行评分工作,考生作答的录音质量会直接影响评分的准确性。在考试和评分过程中及时发现和处理异常录音样本能够有效保证考试顺利平稳进行,同时能够充分保证考生权益和考试公平。本文以CET-SET模拟考试中的数据为研究对象,对CET-SET录音数据的质量进行分析,提出针对CET-SET这类复杂环境下考试的录音质量保障方法和串联式录音异常样本检出方法,确保所有考生的作答录音能够进行最终准确评分,为保障CET-SET考试后续大规模开展奠定了坚实基础。

^(124)I标记抗体及抗体片段用于胃癌动物模型表皮生长因子受体表达水平

西妥昔单抗(Cetuximab)常用于晚期胃癌肿瘤患者的治疗,获得患者肿瘤表皮生长因子受体(Epidermal growth factor receptor,EGFR)的整体表达水平对于预测西妥昔单抗的疗效尤为重要。本研究拟通过对比研究的方式筛选最符合临床需求的靶向EGFR的探针。本研究基于西妥昔单抗通过酶切法制备了Cet-F(ab')_(2)和Cet-Fab,并偶联CY3-NHS酯(Cyanine 3 NHS ester)得CY3-Cetuximab、CY3-Cet-F(ab')_(2)和CY3-Cet-Fab进行细胞荧光实验以验证亲和力。通过Iodogen(1,3,4,6-四氯-3α,6α-二苯基甘脲)法制备得到3种^(124)I标记的分子探针:^(124)I-Cetuximab、^(124)I-Cet-F(ab')_(2)和^(124)I-Cet-Fab,使用micro-PET/CT分别在探针注射后1 h、3 h、6 h、12 h显像进行对比研究。最后,通过生物学分布实验探究3种探针在各时间点在体内的分布情况,采用两独立样本t检验进行组间比较。西妥昔单抗经过片段化后,亲和力无显著降低。Cetuximab、Cet-F(ab')_(2)和Cet-Fab分子量分别约为150 kDa、100 kDa和50 kDa。经^(124)I标记并纯化后,^(124)I-Cetuximab、^(124)I-Cet-F(ab')_(2)和^(124)I-Cet-Fab放射化学纯度均大于94%,比活度均约为2×10^(4) MBq/μmol。^(124)I-Cetuximab、^(124)I-Cet-F(ab')_(2)和^(124)I-Cet-Fab在生理盐水和胎牛血清(FBS)中稳定性好,体外放置24 h放射化学纯度仍高于90%。Micro-PET/CT显像显示在^(124)I-Cet-Fab尾静脉注射后3 h肿瘤部位明显浓聚,^(124)I-Cet-F(ab')_(2)尾静脉注射后12 h肿瘤部位明显浓聚,而^(124)I-Cetuximab尾静脉注射后12 h肿瘤部位仍无明显显像剂分布。生物学分布结果与micro-PET/CT结果一致。3种正电子探针中,^(124)I-Cet-Fab代谢速度最快,肿瘤最早显象的同时有最少的累积辐射剂量,有一定的临床转化潜力。