聚合物添加剂作为形貌调节剂提升全小分子有机太阳能电池的效率和稳定性

活性层形貌的调控是实现全小分子有机太阳能电池高效率和稳定性的关键.本文将聚合物给体PM7作为形貌调节剂加入到BTTzR∶Y6二元体系中,制备了三元全小分子有机太阳能电池.研究结果表明,少量PM7的加入能够有效改善共混膜中的微观纳米结构和分子堆积,促使器件获得更加有效的激子解离和载流子传输;相应器件的短路电流和填充因子显著提升,最终能量转化效率从二元器件的13.9%提高到三元器件的16.0%.值得注意的是,三元器件的热稳定性大幅提升,在85℃加热2200 min后依然能够保持初始效率的79%;而二元器件则大幅衰减到初始效率的43%.以上结果表明,添加聚合物添加剂可以有效地调节共混膜形貌,以获得高效和稳定的全小分子有机太阳能电池.

水下磁谐振式电能传输最大效率追踪方法

磁谐振式电能传输系统在海水中工作时电磁波受到海水强烈的衰减导致输出功率较低。同时,由于发射和吸收端的阻抗不匹配导致部分能量被吸收端反射进而被海水衰减,造成效率的进一步降低。为了提高系统的传输效率和减小能量损失,本文提出了一种输出稳定型最大效率追踪方法,不仅实现了最大效率追踪,还保证了在一定条件下传输效率的稳定,保护了负载。本文运用仿真软件建立模型,对该方法进行了仿真验证;设计并制作了一个谐振耦合传输装置,通过实验研究证明了该方法对水下电磁谐振电能传输系统效率有显著提高作用。

N-乙酰基转移酶10通过催化赖氨酸残基和胞嘧啶碱基的乙酰化修饰在多种生物学过程和疾病中发挥作用

N-乙酰基转移酶10(N-acetyltransferase 10,NAT10)是一种具有乙酰基转移酶活性的核仁蛋白质,可催化蛋白质赖氨酸残基和RNA胞嘧啶碱基的乙酰化修饰。近年来,大量研究表明,这些乙酰化修饰在端粒酶活性调节、细胞基本且核心功能的调节、细胞胁迫响应、DNA损伤修复、细胞周期调控、核糖体RNA的生物学合成、mRNA稳定性及翻译效率的调节等多种生命活动中发挥重要作用,并且与人类癌症、Hutchinson-Gilford早衰综合症(Hutchinson-Gilford premature aging syndrome,HGPS)的发生、发展和预后密切相关。然而,关于NAT10的研究仍存在一些局限性,例如NAT10完整的结构以及这些结构对其功能的影响仍未知,由NAT10调控的细胞基本功能也尚不清楚,并且NAT10对人类癌症和HGPS发展的具体影响机制也待阐明。本文从NAT10的结构、酶活性、生物学功能及其在疾病中的作用进行了综述,并提出了目前研究的局限性,展望了未来的研究方向,以期为NAT10的相关研究提供参考。

运用机电技术提升企业生产效率

机电一体化技术是机械工程技术、微电子工程技术和信息工程技术的结合体,目前机电一体化技术体系已非常完善,随着机电一体化产品在国民经济各个领域中的不断应用,其市场容量不断扩大,价格越来越低,售后服务体系日趋完善,机电一体化技术和产品的应用已具有了很高的性价比,把机电一体化技术及产品应用到齿轮生产线改造中,对齿轮产品工艺提升,生产效率的提高,以及不良品率的降低有显著的效果。

熔喷聚丙烯驻极体过滤材料对医用消毒剂的耐受性研究

本文在前期工作的基础上,采用浸泡方法研究了材料在医用消毒剂作用下的过滤效率稳定性。结果表明:经双氧水、苯酚、戊二醛、含氯消毒剂、硼酸、甲醛、过氧乙酸和消毒酒精等医用消毒剂浸泡后,其过滤效率几乎不会衰减。但材料用洗洁精和洗衣粉清洗时,其过滤性能下降较大。因此,熔喷聚丙烯驻极体过滤材料在医用环境中使用具备良好的稳定性,可作为医用防护口罩的首选材料,并建议作为一次性呼吸防护用品使用。

分子泵整机装配工艺过程的综合评价

分子泵的装配顺序对分子泵的运行情况和抽气性能具有较大影响,为了优化分子泵装配工艺,需要综合考虑装配操作方便性、装配精度保证性、工艺简单性和装配可行性等影响分子泵装配的因素,通过装配序列的综合评价方法,建立装配序列评价模型,获取最优的装配序列,从而在最优装配序列的指导下,优化装配工艺流程并设计专用装配装置,提高分子泵装配效率和质量稳定性。

协同式自适应巡航技术发展现状及趋势

研究了CACC的车车通讯技术、队列稳定性及安全性控制技术、节能及交通效率提升技术的发展现状和存在的问题,指出了其发展趋势,为国内相关技术的发展提供参考。

阴极界面修饰层改善平面p-i-n型钙钛矿太阳能电池的光伏性能

有机/无机杂化金属卤化物钙钛矿半导体材料结合了有机材料良好的溶液可加工性以及无机材料优越的光电特性,近几年受到了热捧,成为太阳能电池领域一颗耀眼的明星.伴随着钙钛矿薄膜结晶过程和形貌的优化、器件结构的改进以及电极界面材料的开发,这类有机/无机杂化金属卤化物钙钛矿太阳能电池的光电转换效率从最初的3.8%迅速提高到目前最高的22.1%.其中界面工程在提升器件性能上发挥着极其重要的作用.本文总结了平面p-i-n型钙钛矿太阳能电池中阴极界面修饰层(CBL)的研究进展.CBL从材料上讲可分为无机金属氧化物、金属或金属盐以及有机材料,从构成上讲可分为单层CBL、双层CBLs以及共混型CBL.本文对这些类型的CBL分别给予详细的介绍.最后,我们归纳出CBL在改善器件效率和稳定性上所起的作用以及理想CBL所应满足的要求,希望能为以后阴极界面修饰材料的设计提供一定的借鉴.

Enhanced cycling stability of Mg-F co-modified LiNi_(0.6)Co_(0.2)Mn_(0.2-y)Mg_yO_(2-z)F_z for lithium-ion batteries

The layered LiNi0.6Co0.2Mn0.2-yMgyO2-zFz（0≤y≤0.12, 0≤z≤0.08） cathode materials were synthesized by combining co-precipitation method and high temperature solid-state reaction, with the help of the ball milling, to investigate the effects of F-Mg doping on LiNi0.6Co0.2Mn0.2O）2. Compared with previous studies, this doping treatment provides substantially improved electrochemical performance in terms of initial coulombic efficiency and cycle performance. The LiNi0.6Co0.2Mn0.11Mg0.09O1.96F0.04 electrode delivers an high capacity retention of 98.6% during the first cycle and a discharge capacity of 189.7 m A·h/g（2.8-4.4 V at 0.2 C）, with the capacity retention of 96.3% after 100 cycles. And electrochemical impedance spectroscopy（EIS） results show that Mg-F co-doping decreases the charge-transfer resistance and enhances the reaction kinetics, which is considered to be the major factor for higher rate performance. It is demonstrated that LiNi0.6Co0.2Mn0.11Mg0.09O1.96F0.04 is a promising cathode material for lithium-ion batteries for excellent electrochemical properties.

Efficient Mass Transport and Electrochemistry Coupling Scheme for Reliable Multiphysics Modeling of Planar Solid Oxide Fuel Cell Stack

A multiphysics model for a production scale planar solid oxide fuel cell （SOFC） stack is important for the SOFC technology, but usually requires an unpractical amount of computing resource. The major cause for the huge computing resource requirement is identified as the need to solve the cathode O2 transport and the associated electrochemistry. To overcome the technical obstacle, an analytical model for solving the O2 transport and its coupling with the electrochemistry is derived. The analytical model is used to greatly reduce the numerical mesh complexity of a multiphysics model. Numerical test shows that the analytical approximation is highly accurate and stable. A multiphysics numerical modeling tool taking advantage of the analytical solution is then developed through Fluent@. The numerical efficiency and stability of this modeling tool are further demonstrated by simulating a 30- cell stack with a production scale cell size. Detailed information about the stack performance is revealed and briefly discussed. The multiphysics modeling tool can be used to guide the stack design and select the operating parameters.

Rapid Regeneration of Chelated Iron Desulfurization Solution Using Electrochemical Reactor with Rotating Cylindrical Electrodes

A new electrochemical reactor with rotating cylindrical electrodes was designed and used to increase the regeneration efficiency of chelated iron desulfurization solution.The influence of operating parameters,such as the rotation speed of electrode,voltage,and inlet air and liquid flow rates,on the regeneration rate was investigated.Compared with the traditional tank-type reactor,the regeneration rate with the new electrochemical reactor was increased significantly.Under the optimum conditions,the regeneration rate was increased from 45.3%to 84.8%.Experimental results of continuous operation indicated that the new electrochemical regeneration method had some merits including higher regeneration efficiency,smaller equipment size and good stability in operation.

中国奶牛不同养殖模式效率的随机前沿分析——来自7省50县监测数据的证据

奶牛养殖模式的选择是奶业走向现代化的重要步骤,为此有必要对不同养殖模式的效率进行实证研究。本文基于7省50县615户奶农的监测面板数据,利用随机前沿分析方法,对散养、小规模、中规模三种养殖模式的效率进行了衡量和比较分析。研究发现,在保持其他因素不变的情况下,中规模、小规模养殖模式的技术效率明显高于散养模式的技术效率;相比散养户来说,中规模、小规模养殖模式的产出效率更稳定。因此,现阶段适度规模养殖是中国奶牛产业发展的目标。

Study on Stability and Efficiency of High-Power Ultrawideband Radiation Source

Investigations are directed to the development of high-power sources ofUWB （ultrawideband） radiation based on excitation of anterma arrays with bipolar voltage pulses. In the previously designed high-power UWB sources only one bipolar pulse former and different feeder systems for pulse distribution through the array elements were used. By means of this approach, a number of UWB sources were created with the bipolar voltage pulse length ranging from 0.2 to 2 ns and effective potential of radiation ranging from 0.4 to 3 MV. The approach has got a restriction related to the electrical breakdown in a bipolar voltage pulse former. A new approach to the creation of high-power UWB sources based on a multicharmel bipolar pulse former is suggested： the number of bipolar pulse formers is equal to the number of antennas in the array. The main problem in realization of this approach is a stable operation of bipolar pulse formers in order to ensure a coherent summation of radiated pulses in the far-field zone. The result of this work is the instability of-150 ps at the pulse length of 3 ns obtained in a one-channel bipolar pulse former indicating that the suggested approach is realizable.

用于聚合物太阳能电池的芳香亚胺类阴极修饰材料及其研究进展

聚合物太阳能电池作为一种新型太阳能电池,具有质量轻、成本低、易于大面积制备等突出优势,在学术界和工业界引起了广泛关注.近年来,聚合物太阳能电池能量转换效率提高迅速,单结器件效率值已超过17%.在器件优化中,构建高效阴极有机修饰层成为提高光伏器件效率与稳定性的重要策略之一.芳香亚胺类阴极修饰材料因具有大共轭平面、优异的电子传输性能、丰富的化学修饰位点以及合适的能级等特点近年来备受关注.本文简单介绍了阴极修饰层材料的功能,总结和评述了苝酰亚胺和萘酰亚胺类阴极修饰材料的研究进展,最后结合实际应用的要求展望了这类材料的未来发展趋势与前景.

Holey platinum nanotubes for ethanol electrochemical reforming in aqueous solution

The catalytic/electrocatalytic performance of platinum(Pt)nanostructures highly relates to their morphology.Herein,we propose a facile self-template pyrolysis strategy at high temperature to synthesize one-dimensionally holey Pt nanotubes(Pt-hNTs)using Pt^(Ⅱ)-dimethylglyoxime complex(Pt^(Ⅱ)-DMG)nanorods as the reaction precursor.The coordination capability of DMG results in the generation of Pt^(Ⅱ)-DMG nanorods,whereas the reducibility of DMG at high temperature leads to the reduction of Pt^(Ⅱ)species in Pt^(Ⅱ)-DMG nanorods.During the reaction process,the inside-out Ostwald ripening phenomenon leads to the hollow morphology of Pt-hNTs.Benefiting from the physical characteristics of hollow and holey structure,Pt-hNTs with clean surface show superior electroactivity and durability for catalyzing ethanol electrooxidation as well as hydrogen evolution reaction in alkaline media.Under optimized experimental conditions,the constructed symmetric Pt-hNTs||Pt-hNTs ethanol electrolyzer only requires an electrolysis voltage of 0.40 V to achieve the electrochemical hydrogen production,demonstrating a highly energy saving strategy relative to traditional water electrolysis.

Improving UV stability of perovskite solar cells without sacrificing efficiency through light trapping regulated spectral modification

The stability of perovskite solar cells is an important issue to be addressed for future applications.Perovskite solar cells are vulnerable to exposure to UV light due to promoted chemical reactions.However, preventing UV light from entering solar cells lowers the power conversion efficiency by reducing the photocurrent. The challenge is to improve UV stability without sacrificing efficiency. Here, we demonstrate the reduction of UV light-related negative effects from the perspective of spectral modification. By simultaneously introducing UV–visible downshifting and light trapping, perovskite solar cells can achieve a comparable efficiency of over 21% to that of an unmodified device. The optimized device obtains increased UV stability due to UV–visible downshifting. Different from other strategies, spectral modification externally alters the composition of incident light and improves UV stability without changing the internal device architecture, which is broadly applicable to perovskite solar cells with different structures. The present work may also find applications in other types of solar cells to boost the stability of devices exposed to UV light.

Solvating power regulation enabled low concentration electrolyte for lithium batteries

Li^(+) solvation structures have a decisive influence on the electrode/electrolyte interfacial properties and battery performances.Reduced salt concentration may result in an organic rich solid electrolyte interface(SEI)and catastrophic cycle stability,which makes low concentration electrolytes(LCEs)rather challenging.Solvents with low solvating power bring in new chances to LCEs due to the weak salt-solvent interactions.Herein,an LCE with only 0.25 mol L^(-1) salt is prepared with fluoroethylene carbonate(FEC)and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropylether(D_(2)).Molecular dynamics simulations and experiments prove that the low solvating power solvent FEC not only renders reduced desolvation energy to Li^(+) and improves the battery kinetics,but also promotes the formation of a LiF-rich SEI that hinders the electrolyte consumption.Li||Cu cell using the LCE shows a high coulombic efficiency of 99.20%,and LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)||Li cell also exhibits satisfying capacity retention of 89.93%in 200 cycles,which demonstrates the great potential of solvating power regulation in LCEs development.

The effects of an experimental drought on the ecophysiology and fruiting phenology of a tropical rainforest palm

Aims Anthropogenic climate change is predicted to increase mean temperatures and rainfall seasonality.How tropical rainforest species will respond to this climate change remains uncertain.Here,we analysed the effects of a 4-year experimental throughfall exclusion(TFE)on an Australian endemic palm(Normambya normanbyi)in the Daintree rainforest of North Queensland,Australia.We aimed to understand the impact of a simulated reduction in rainfall on the species’physiological processes and fruiting phenology.Methods We examined the fruiting phenology and ecophysiology of this locally abundant palm to determine the ecological responses of the species to drought.Soil water availability was reduced overall by~30%under a TFE experiment,established in May 2015.We monitored monthly fruiting activity for 8 years in total(2009–2018),including 4 years prior to the onset of the TFE.In the most recent year of the study,we measured physiological parameters including photosynthetic rate,stomatal conductance and carbon stable isotopes(δ13C,an integrated measure of water use efficiency)from young and mature leaves in both the dry and wet seasons.Important Findings We determined that the monthly fruiting activity of all palms was primarily driven by photoperiod,mean solar radiation and mean temperature.However,individuals exposed to lower soil moisture in the TFE decreased significantly in fruiting activity,photosynthetic rate and stomatal conductance.We found that these measures of physiological performance were affected by the TFE,season and the interaction of the two.Recovery of fruiting activity in the TFE palms was observed in 2018,when there was an increase in shallow soil moisture compared with previous years in the treatment.Our findings suggest that palms,such as the N.normanbyi,will be sensitive to future climate change with long-term monitoring recommended to determine population-scale impacts.

A novel dopant for spiro-OMeTAD towards efficient and stable perovskite solar cells

2,2’,7,7’-tetrakis-(N,N-di-4-methoxyphenylamino)-9,9’-spirobifluorene(spiro-OMeTAD), as the most commonly used hole transport material(HTM), plays a significant role in the normal structured(n-i-p) high-efficiency perovskite solar cells(PSCs). In general, it is prepared by a halogen solvent(chlorobenzene, CBZ) and needs an ion dopant(lithium bis(trifluoromethanesulfonyl)imide, Li-TFSI) to improve its conductivity and hole mobility. However, such a halogen solvent is not environmentally friendly and the widely used LiTFSI dopant would affect the stability of PSCs. Herein, we develop a non-halogen solvent-tetrahydrofuran(THF)-prepared spiro-OMeTAD solution with a new p-type dopant,potassium bis(fluorosulfonyl)imide(K-FSI), to apply into PSCs. By this strategy, high-hole-mobility spiro-OMeTAD film is achieved. Meanwhile, the potassium ions introduced by diffusion into perovskite surface passivate the interfacial defects. Therefore, a hysteresis-free champion PSC with an efficiency of 21.02% is obtained, along with significantly improved stability against illumination and ambient conditions. This work provides a new strategy for HTMs toward hysteresis-free high-efficiency and stable PSCs by substituting dopants.

Achieving superior high-temperature sodium storage performance in a layered potassium vanadate

The high-temperature sodium-ion batteries(SIBs)used for large-scale energy storage have attracted extensive attention in recent years.However,the development of SIBs is still hampered mainly by their poor charge/discharge efficiency and stability,necessitating the search for appropriate electrodes.A simple potassium ion intercalation process is used herein to obtain the potassium vanadate(KV_(3)O_(8))nanobelts.When serving as the anode for SIBs at a high temperature(60℃),the KV_(3)O_(8) nanobelts display superior sodium storage performance with a high capacity of 414mA h g^(-1) at 0.1Ag^(-1),remarkable rate capability(220mAh g^(-1) at 20Ag^(-1)),and super-long cycle life(almost no capacity fading at 10Ag^(-1) over 1000 cycles).Moreover,the ex-situ X-ray powder diffraction reveals no structural changes throughout the whole charge/discharge process,which further confirms their outstanding stability,indicating KV_(3)O_(8) nanobelts are a promising candidate for high-temperature SIBs.