Comparative Study of Two Carbon Fiber Cathodes and Theoretical Analysis in Microbial Fuel Cells on Ocean Floor

Cathode activity plays an important role in the improvement of the microbial fuel cells on ocean floor （BMFCs）. A comparison study between Rayon-based （CF-R） and PAN-based carbon fiber （CF-P） cathodes is conducted in the paper. The two carbon fibers were heat treated to improve cell performance （CF-R-H ＆ CF-P-H）, and were used to build a new BMFCs structure with a foamy carbon anode. The maximum power density was 112.4mWm-2 for CF-R-H, followed by 66.6mWm-2 for CF-R, 49.7 mWm-2 for CF-P-H and 21.6mWm-2 for CF-P respectively. The higher specific area and deep groove make CF-R have a better power output than with CF-P. Meanwhile, heat treatment of carbon fiber can improve cell power, nearly two-fold higher than heat treatment of plain fiber. This improvement may be due to the quinones group formation to accelerate the reduction of oxygen and electron transfer on the fiber surface in the three phase boundary after heat treatment. Compared to PAN-based carbon fiber, Rayon-based carbon fiber would be preferentially selected as cathode in novel BMFCs design due to its high surface area, low cost and higher power. The comparison research is significant for cathode material selection and cell design.

Carbon Foam Anode Modified by Urea and Its Higher Electrochemical Performance in Marine Benthic Microbial Fuel Cell

Electrode materials have an important effect on the property of microbial fuel cell(MFC). Carbon foam is utilized as an anode and further modified by urea to improve its performance in marine benthic microbial fuel cell(BMFC) with higher voltage and output power. The electrochemical properties of plain carbon foam(PC) and urea-modified carbon foam(UC) are measured respectively. Results show that the UC obtains better wettability after its modification and higher anti-polarization ability than the PC. A novel phenomenon has been found that the electrical potential of the modified UC anode is nearly 100 m V lower than that of the PC, reaching-570 ±10 m V(vs. SCE), and that it also has a much higher electron transfer kinetic activity, reaching 9399.4 m W m-2, which is 566.2-fold higher than that from plain graphite anode(PG). The fuel cell containing the UC anode has the maximum power density(256.0 m W m-2) among the three different BMFCs. Urea would enhance the bacteria biofilm formation with a more diverse microbial community and maintain more electrons, leading to a lower anodic redox potential and higher power output. The paper primarily analyzes why the electrical potential of the modified anode becomes much lower than that of others after urea modification. These results can be utilized to construct a novel BMFC with higher output power and to design the conditioner of voltage booster with a higher conversion ratio. Finally, the carbon foam with a bigger pore size would be a potential anodic material in conventional MFC.

Electrochemical Properties of Electrodes with Different Shapes and Diffusion Kinetic Analysis of Microbial Fuel Cells on Ocean Floor

Microbial fuel cell(MFC) on the ocean floor is a kind of novel energy-harvesting device that can be developed to drive small instruments to work continuously.The shape of electrode has a great effect on the performance of the MFC.In this paper,several shapes of electrode and cell structure were designed,and their performance in MFC were compared in pairs:Mesh(cell-1) vs.flat plate(cell-2),branch(cell-3) vs.cylinder(cell-4),and forest(cell-5) vs.disk(cell-6) FC.Our results showed that the maximum power densities were 16.50,14.20,19.30,15.00,14.64,and 9.95 mWm-2 for cell-1,2,3,4,5 and 6 respectively.And the corre-sponding diffusion-limited currents were 7.16,2.80,18.86,10.50,18.00,and 6.900 mA.The mesh and branch anodes showed higher power densities and much higher diffusion-limited currents than the flat plate and the cylinder anodes respectively due to the low diffusion hindrance with the former anodes.The forest cathode improved by 47% of the power density and by 161% of diffusion-limited current than the disk cathode due to the former's extended solid/liquid/gas three-phase boundary.These results indicated that the shape of electrode is a major parameter that determining the diffusion-limited current of an MFC,and the differences in the elec-trode shape lead to the differences in cell performance.These results would be useful for MFC structure design in practical applica-tions.

Pyrolyzed Iron Phthalocyanine-Modified Multi-Walled Carbon Nanotubes as Composite Anode in Marine Sediment Microbial Fuel Cells and Its Electrochemical Performance

Improving the performance of anode is a crucial step for increasing output power of marine sediment microbial fuel cells(MSMFCs)to drive marine monitor to work for a long term on the ocean floor.A pyrolyzed iron phthalocyanine modified multi-walled carbon nanotubes composite(FePc/MWCNTs)has been utilized as a novel nodified anode in the MSMFC.Its structure of the composite modified anode and electrochemical performance have been investigated respectively in the paper.There is a substantial improvement in electron-transfer efficiency from the bacteria biofilm to the modified anode via the pyrolyzed FePc/MWCNTs composite based on their cyclic voltammetry(CV)and Tafel curves.The electron transfer kinetic activity of the FePc/MWCNTs-modified anode is 1.86 times higher than of the unmodified anode.The maximum power density of the modified MSMFC was 572.3±14 m W m^-2,which is 2.6 times larger than the unmodified one(218.3±11 m W m^-2).The anodic structure and cell scale would be greatly minimized to obtain the same output power by the modified MSMFC,so that it will make the MSMFC to be easily deployed on the remote ocean floor.Therefore,it would have a great significance for us to design a novel and renewable long term power source.Finally,a novel molecular synergetic mechanism is proposed to elucidate its excellent electrochemical performance.

Influence of Cathode Modification by Chitosan and Fe^(3+)on the Electrochemical Performance of Marine Sediment Microbial Fuel Cell

The electrochemical performances of cathode play a key role in the marine sediment microbial fuel cells(MSMFCs)as a long lasting power source to drive instruments,especially when the dissolved oxygen concentration is very low in seawater.A CTS-Fe^(3+)modified cathode is prepared here by grafting chitosan(CTS)on a carbon fiber surface and then chelating Fe^(3+)through the coordination process.The electrochemical performance in seawater and the output power of the assembled MSMFCs are both studied.The results show that the exchange current densities of CTS and the CTS-Fe^(3+)group are 5.5 and 6.2 times higher than that of the blank group,respectively.The potential of the CTS-Fe^(3+)modified cathode increases by 138 mV.The output power of the fuel cell(613.0 mW m^(-2))assembled with CTS-Fe^(3+)is 54 times larger than that of the blank group(11.4 mW m^(-2))and the current output corresponding with the maximum power output also increases by 56 times.Due to the valence conversion between Fe^(3+)and Fe^(2+)on the modified cathode,the kinetic activity of the dissolved oxygen reduction is accelerated and the depolarization capability of the cathode is enhanced,resulting higher cell power.On the basis of this study,the new cathode materials will be encouraged to design with the complex of iron ion in natural seawater as the catalysis for oxygen reduction to improve the cell power in deep sea.

3-Aminopropyltriethoxysilane Complexation with Iron Ion Modified Anode in Marine Sediment Microbial Fuel Cells with Enhanced Electrochemical Performance

Anode modification plays a key role in higher power output in marine sediment microbial fuel cells(MSMFCs).A low-molecular organosilicon compound(3-aminopropyltriethoxysilane)was grafted onto the surface of carbon felt using chemical method and a composite modified anode was prepared through organic ligands coordination Fe^(3+)for better electro-chemical per-formance.Results show that the biofilm resistance of the composite modified anode(2707Ω)is 1.3 times greater than that of the unmodified anode(2100Ω),and its biofilm capacitance also increases by 2.2 times,indicating that the composite modification pro-motes the growth and attachment of electroactive bacteria on the anode.Its specific capacitance(887.8 Fm^(−2))is 3.7 times higher than that of unmodified anode,generating a maximum current density of 1.5Am^(−2).In their Tafel curves,the composite modified anodic exchange current density(5.25×10^(−6)Acm^(−2))is 5.8 times bigger than that of unmodified anode,which suggests that the electro-chemical activity of redox,anti-polarization ability and electron transfer kinetic activity are significantly enhanced.The marine sediment microbial fuel cell with the composite modified anode generates the higher power densities than the blank(203.8mWm^(−2) versus 45.07mWm^(−2)),and its current also increases by 4.4 times.The free amino groups on the anode surface expands a creative idea that the modified anode ligates the natural Fe(Ⅲ)ion in sea water in the MSMFCs for its higher power output.

Humic Acid and Iron Chelation Modified Anode Improves the Electrochemical Performance of Marine Sediment Microbial Fuel Cell

Marine sediment microbial fuel cell(MSMFCs)can be utilized as a long lasting power source to drive small instruments to work for long time on ocean floor and its higher power has a significant meaning for practical application.Anode modification can greatly improve the performance of MSMFCs.Herein,humic acid(HA)and humic acid-iron ion complex(HA-Fe)were used to modify the anode for constructing a better MSMFCs.The results indicated that HA-Fe modified anode,better than HA modification,significantly improved the MSMFCs cell power output.The maximum power density of HA-Fe modified MSMFCs is 165.3 mW m−2,which are 6.5-folds of blank MSMFCs.The number of microorganisms on anode,redox activity,and relative kinetic activity were 1.8-,6.1-,and 13.1-folds of blank MSMFCs,respectively.The MSMFCs improvement would be attributed to the electron transfer media of HA and the valence conversion of Fe ions.A synergistic interaction between the naturally occurring HA and Fe ions on the anodic surface in marine sediments would make the modified anodes have‘renewable’characteristics,which is beneficial for the MSMFCs to maintain its long-term higher power.

我国青少年无偿献血科普工作实践研究——结合广州市近五年“献血健康”宣教项目的案例分析

无偿献血是中国公民的健康素养。本文通过对献血宣教和健康教育相关理论研究现状的文献综述,得出青少年时期作为人生发展的关键期,对其开展无偿献血健康教育工作,有利于18岁成人后参加无偿献血、保障社会面临床用血、促进全民健康,做好血源开发系统性基础性健康促进工作的结论。并回顾了广州血液中心2020—2024年“献血健康”青少年科普项目,总结了青少年献血科普若干“青”字号服务品牌的实践成果,提出了构建“市-区-社区”三级联动的青少年无偿献血宣教工作队的研究展望。

基于独立分类网络的开集识别研究

【目的】为解决图像分类模型面对传统闭集训练方式出现的模型缺乏开集泛化性的问题,提出了一种分离式的独立分类网络结构。【方法】每个类别都包含独立的线性特征层,特征层中设计的神经元节点能够在有限的数据样本下更准确地捕获类别特征。同时,在模型训练时,文中引入了一类无需标注的负样本,使得模型在构建决策边界时不仅依赖于已知类别的特征差异,在不增加额外标注样本的情况下,增加模型决策边界的开集泛化性。【结果】结果表明:独立分类网络开集识别(ICOR)模型结构和开集自适应训练策略均能有效改善传统模型开放集识别(OSR)性能;随着开放度的增加,能表现出更好的鲁棒性,能更有效地降低模型的OSR风险。【结论】提出的独立分类网络并融合开集自适应训练的算法比现有开集识别算法具有更优的开集识别性能。

广东省无偿献血志愿服务队运行现状分析

目的调查广东省无偿献血志愿服务队的运行现状,分析现存问题。方法2016年6月对全省的31家采供血机构的无偿献血志愿服务队在册人数和有效运行人数（指每年参与志愿服务3次以上的志愿者数）相关情况开展问卷调查（调查表回收有效率为90.32%）,通过SPSS20软件运用单因素分析方法进行数据分析。结果全省服务队平均有效运行率41.83%,远低于全国平均水平（66.68%）。其中,按服务队所在地采供血机构规模分组比较,省级血液中心、其他血液中心、中心血站以及血站、血库的服务队有效运行率分别为53.85%、20.83%、44.03%和17.59%;按服务队所在地年献血人次（n）分组比较,n≥200000、50000≤n〈200000、20000≤n〈50000、10000＜n≤20000和n≤10000的服务队有效运行率分别为53.85％、33.54％、57.11％、16.95％以及0％。2种分组比较模型的F值和P值提示组间有显著性差异，并且差异有统计学意义。讨论广东省无偿献血志愿服务队的有效运行水平低于全国平均水平。省内各地区的有效运行水平参差，建队时间与服务队有效运行没有必然联系。献血人数少的地区，服务队运行的效果差。总体上，服务队在志愿者管理、组织建设、招募方式和营运资金等方面可能存在问题。结论建议进一步运用定量分析和定性分析相结合的方法，探索改善广东省无偿献血志愿服务队管理运行的对策。

《国朝文棷题辞》与清代古文的图景构建

《国朝文棷题辞》是清代最大的一部当代文话,它有选择性地评论清代古文家三百多人,推崇文能自立之文家,有意识地将古文分成义理、考据、辞章、经济四类之文,对于释经传史之文颇加推尊。平步青将清代古文分成了三个阶段:顺治、康熙时期的古文一扫晚明文风积习,呈现出百家争流的特点;雍正、乾隆时期的古文流派众多,平步青提出了桐城、阳湖、江西、闽派、浙派五大文派之说;嘉庆迄同治,则表现出以桐城派之扩展与对抗为发展的主要趋势。平步青还从地域和家族两个角度评论了清代古文的特点,重点评论了江西、浙江、江苏、福建等九个地域和其间家族的古文发展史。对于清代的古文文体,平步青对奏疏、表文、文告、制艺文、考据文都有特别的注意,表现出异于时流又相对客观的审美趣味。可以说,《国朝文棷题辞》通过目录体的写作方式,呈现出了清代古文的基本图景。

地方风习与主流建构——晚清民初浙江词人的词学选择与词风嬗变

晚清民初词坛为常州词派所笼罩,浙江词人虽有其浙西词派宗风,但亦因时代风气之发展,词学内部之变化,而受到常州词派比较大的影响。在词学门径上,由以师法姜、张为主变成出入诸家之间;在词学风格上,由南返北,风格更为多元;在词学宗旨上,则由浙入常,浙江词人对于常派,或自觉地融入,或依违于浙、常二派之间而实以常派为主,或开径独行,但仍可清楚看出常州词派的印迹。这说明晚清民初词学发展的大势,正是因为这么一批浙江词人参与主流词学建设,常州词派的词学影响更趋广大,常州词派的理论也更趋圆融,也使得传统词学向现代词学的演进加快了进程。

评点之学:论俞平伯词学方法的学术渊源及其超越

现代词学家俞平伯出身文学世家,其词学方法具有深刻的传统学术渊源。评点之学即其一。在注重文本的章法、结构方面,俞平伯受古文评点较深;在评点的细致、用语的生动活泼方面,又受小说评点的影响;在对词作风格的细致辨认和词史的比较视野方面,俞平伯又受词集评点的影响。同时,俞平伯对传统的评点之学又有所突破,主要表现在于纵横捭阖的比较批评方法的运用和会通艺文的批评理念和路径。综而言之,俞平伯词学研究是在吸收了传统评点方法的优长之处的基础上而进一步发展的。

基于节点流量重要度的电网关键节点辨识

当电力系统发生大规模连锁故障的时候,电网中的某些关键节点可能会对故障的扩大起着推动的作用。为了提高关键节点辨识的准确性以及更好地预防大规模连锁故障的发生,本文提出了基于节点流量重要度的电网关键节点辨识方法。该方法通过定义节点传输贡献度指标和节点传输效率,然后基于电网节点潮流传输贡献重要度矩阵,计算各节点的节点流量重要度并进行比较。最后,通过对IEEE 39节点系统和南方某区域电网进行仿真,所得仿真结果表明本文所提方法计算的指标可以定量表征某个节点在潮流传输及其在电网拓扑结构中的重要度,可以有效、准确地辨识出电网中的关键节点,判断它们在交直流电网自组织临界演化过程中的作用,对预防系统向连锁故障临界状态演化有着重要的意义。

风电场与电铁同母线接入对供电质量的影响研究

基于实际工程,借助电磁暂态仿真软件EMTP-RV,建立了广西灵川县灵田风电场的详细仿真模型及与风电场接入同一变电站110 k V母线的灵川电铁牵引站及机车负荷模型。研究了风电场在不同风速出力和电铁负荷状态下公共接入点电能质量,以及风电场与电铁牵引负荷接入同一110 k V母线的相互影响。并开发了电能质量计算模板用于多种电能质量指标的计算。多种运行工况的仿真表明,风电场与电铁负荷接入同一母线会恶化电网的运行条件,导致公共接入点剧烈电压波动,并向公共电网注入大量谐波。针对仿真中揭示的电压波动与功率振荡现象,结合现场条件,针对性提出合理调度风电出力、谐波治理与无功补偿等多项改善措施,使接入点的电能质量满足国家标准。

氧化物靶材的制备及研究进展

氧化物靶材是一种关键性镀膜基材,主要用于磁控溅射制备TFT薄膜,并将其应用于晶体管等器件中透明电极、半导体沟道层,同时也广泛应用于显示面板领域。为满足高性能器件对薄膜的要求,氧化物靶材逐渐向高致密、大尺寸、异形化方向发展。以显示行业中氧化物靶材作为重点,介绍了氧化物靶材制备流程,主要从素坯成型、烧结工艺两个角度对氧化物靶材进行总结,分析了烧结工艺对靶材参数与溅射薄膜电阻率、光学透射率及粗糙度等方面的影响,最后阐述了国内外氧化物靶材市场的现状及发展趋势。

射频消融辅助肝切除术在肝细胞癌治疗中的应用

目的探讨射频消融辅助肝切除术(RF-LR)在肝细胞癌治疗中的有效性。方法收集2016年1月至2019年6月在郑州大学第一附属医院接受肝切除术的Ⅰa、Ⅰb、Ⅱa期肝细胞癌患者173例,其中82例采用RF-LR(RF-LR组,n=82),91例采用传统的钳夹结扎法肝切除术(CC-LR组,n=91),比较2组手术中的基本情况、术后肝功能、术后并发症、住院时间、住院费用及术后36个月内肿瘤转移复发情况。结果RF-LR组手术时间、术中出血量、肝门阻断时间均较CC-LR组低(P均<0. 05);2组术中输血比较差异无统计学意义(P>0. 05)。RF-LR组术后并发症较CC-LR组低(P <0. 05);RF-LR组住院总费用均较CC-LR组高(P <0. 05);2组术后第1天和第4天谷丙转氨酶、谷草转氨酶、总胆红素、白蛋白水平,以及住院时间比较差异均无统计学意义(P均> 0. 05)。RF-LR组术后12、24、36个月无瘤生存均优于CC-LR组(P均<0. 05)。结论 RF-LR在肝细胞癌治疗中具有较大应用价值,不仅能有效降低患者手术时间、术中出血量以及并发症,还能使其获得更好的长期生存率,但该方案治疗费用更高。

Oxidation Modification of Polyacrylonitrile-Based Carbon Fiber and Its Electro-Chemical Performance as Marine Electrode for Electric Field Test

A novel sensor for ocean electric field testing has been fabricated by polyacrylonitrile-based on carbon fibers with electro-chemical oxidation.The surface profile characteristics of the carbon fibers were characterized by scanning electron microscope,Fourier transform infrared spectra and contact angle.Cyclic voltammetry and Tafel curves have been used to study its electro-chemical performances.Two identical electrodes in sea water as the electric field sensor will swiftly respond to applied electric field which causes positive and negative ions to move in opposite direction,resulting in a electric potential difference(ΔE).Test result indicates that the offset potential is typically below 1 m V with a drift of 60-170μVd^-1.Typical self noise level is 1.07 nV√Hz^(1/2)@1 Hz.The electric field response indicates that the modified electrode pair shows better response to AC sine signal of amplitude and frequency(5 mV and 1 mHz)respectively than its blank.The electric field response model of the modified electrodes is creatively presented according to its electric double layer capacitance and Faraday pseudo-capacitance.Many advantages of the carbon fiber electric field electrode will make it have potential application prospect.

基于倾向性评分匹配法评价术后辅助性经导管肝动脉化疗栓塞对大肝癌根治性切除术后复发风险的影响

目的探讨大肝癌(>5 cm)术后早期复发的影响因素及术后辅助性经导管肝动脉化疗栓塞(PA-TACE)对大肝癌患者复发的影响。方法回顾性分析郑州大学第一附属医院2015年2月至2019年7月首次行肝癌根治性手术切除并经病理证实肝细胞肝癌患者165例的临床资料。根据是否接受PA-TACE治疗分为单纯手术组和PA-TACE组。采用倾向性评分匹配法(PSM)和Kaplan-Meier生存分析分别比较匹配前、后2组的无复发生存率和早期无复发生存率。采用限制性立方样条模型评估PA-TACE组患者发生早期复发风险随肿瘤大小变化的情况。结果165例患者中,50例接受了PA-TACE治疗。经PSM匹配后,PA-TACE组的12、36和60个月无复发生存率明显高于单纯手术组(82.9%、59.2%、43.3%和46.3%、19.5%、13.0%,P均<0.001)。PA-TACE降低了术后早期复发(<2 a)的风险(匹配前P<0.001;匹配后P<0.001)。多因素COX回归分析显示PA-TACE是延长早期无复发生存时间的独立性保护因素(P<0.001)。限制性立方样条模型显示肿瘤直径>7.5 cm的PA-TACE患者,术后早期复发风险随肿瘤直径的增加而增加。结论PA-TACE可降低大肝癌根治性切除术后的复发风险,对于>10 cm的巨大肝癌患者,可根据术后肝功能恢复情况及乙肝病毒DNA定量选择PA-TACE治疗或联合其他辅助治疗以改善预后。

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