High performance wide bandgap perovskite solar cell with low V_(OC) deficit less than 0.4 V

Wide bandgap perovskite solar cells(PSCs)have attracted significant attention because they can be applied to the top cells of tandem solar cells.However,high open-circuit voltage(V_(OC))deficit(>0.4 V)result from poor crystallization and high non-radiative recombination losses become a serious limitation in the pursuit of high performance.Here,the relevance between different Pbl_(2)proportions and performance parameters are revealed through analysis of surface morphology,residual stress,and photostability.The increase of Pbl_(2)proportion promotes crystal growth and reduces the work function of the perovskite film surface and promotes the energy level alignment with the carrier transport layer,which decreased the V_(OC)deficit.However,residual PbI_(2)exacerbated the stress level of perovskite film,and the resulting lattice disorder deteriorated the photostability of the device.Ultimately,after the synergistic passivation of residual PbI_(2)and PEAI,the V_(OC)achieves 1.266 V and V_(OC)deficit is less than 0.4 V,the record value in wide bandgap PSCs.

Productivity Prediction Model of Perforated Horizontal Well Based on Permeability Calculation in Near-Well High Permeability Reservoir Area

To improve the productivity of oil wells,perforation technology is usually used to improve the productivity of horizontal wells in oilfield exploitation.After the perforation operation,the perforation channel around the wellbore will form a near-well high-permeability reservoir area with the penetration depth as the radius,that is,the formation has different permeability characteristics with the perforation depth as the dividing line.Generally,the permeability is measured by the permeability tester,but this approach has a high workload and limited application.In this paper,according to the reservoir characteristics of perforated horizontal wells,the reservoir is divided into two areas:the original reservoir area and the near-well high permeability reservoir area.Based on the theory of seepage mechanics and the formula of open hole productivity,the permeability calculation formula of near-well high permeability reservoir area with perforation parameters is deduced.According to the principle of seepage continuity,the seepage is regarded as the synthesis of two directions:the horizontal plane elliptic seepage field and the vertical plane radial seepage field,and the oil well productivity prediction model of the perforated horizontal well is established by partition.The model comparison demonstrates that the model is reasonable and feasible.To calculate and analyze the effect of oil well production and the law of influencing factors,actual production data of the oilfield are substituted into the oil well productivity formula.It can effectively guide the technical process design and effect prediction of perforated horizontal wells.

基于硅烷化石墨烯掺杂硅橡胶的聚合物电致动器

以有机锡为催化剂、异佛尔酮二异氰酸酯(IPDI)为偶联剂,将端羟基-聚二甲基硅氧烷(HO-PDMS)接枝到氧化石墨烯(GO)的表面,制备了硅烷化氧化石墨烯(SGO)。红外光谱、拉曼光谱和X射线光电子能谱结果证明了HO-PDMS的成功接枝。通过扫描电子显微镜观测到SGO均匀分散在硅橡胶(PDMS)基体中,由此得介电常数和力学性能提升的SGO/PDMS复合膜。当添加10 phr SGO后,复合膜的相对介电常数达到3.076,较纯PDMS膜增加了40.7%。在复合膜两侧涂覆柔性PDMS/炭黑电极,制备了SGO/PDMS膜介电弹性体电致动器(DEP)。该致动器在4.71 V/μm(2 Hz)的低压电场下发生面外弯曲振动,中心偏转位移达到0.654 mm,折合膜形变率为5.42%,在文献已报道的同类产品中处于较高水平。

高拉伸自黏附导电P(AAS-VPA)/P(EA-MAA)复合水凝胶的传感应用

以丙烯酸钠(AAS)、丙烯酸乙酯-甲基丙烯酸共聚物P(EA-MAA)和乙烯磷酸(VPA)为原料,制备了具有高拉伸性(>2000%的断裂伸长率)、良好的电导率(~0.0343 S/cm)及优异的表面自适应性黏附力(黏附金属、玻璃、木材、橡胶等多种基材,其中对橡胶的黏附强度高达250 N/m)的复合水凝胶P(AAS-VPA)/P(EA-MAA)。该水凝胶不仅能够随皮肤适时变形,而且具有高的灵敏度(GF=4.40)、宽的应变范围(0%~200%)及良好的稳定性,能够动态监测身体的各类运动(诸如手指弯曲、胳膊弯曲等)。这种集高拉伸性、导电性及自黏性于一体的多功能水凝胶能够适应多种应用场景,为水凝胶在柔性电子领域的应用提供了材料范例。

Improved nitrogen reduction electroactivity by unique MoS_(2)‐SnS_(2) heterogeneous nanoplates supported on poly(zwitterionic liquids)functionalized polypyrrole/graphene oxide

Unique MoS_(2)‐SnS_(2)heterogeneous nanoplates have successfully in‐situ grown on poly(3‐(1‐vinylimidazolium‐3‐yl)propane‐1‐sulfonate)functionalized polypyrrole/graphene oxide(PVIPS/PPy/GO).PVIPS can attract heptamolybdate ion(Mo7O246−)and Sn^(4+)as the precursors by the ion‐exchange,resulting in the simultaneous growth of 1T’‐MoS2 and the berndtite‐2T‐type hexagonal SnS_(2)by the interfacial induced effect of PVIPS.The obtained MoS_(2)‐SnS_(2)/PVIPS/PPy/GO can serve as electrocatalysts,exhibiting good NRR performance by the synergistic effect.The semi‐conducting SnS_(2)would limit the surface electron accessibility for suppressing HER process of 1T’‐MoS_(2),while metallic 1T’‐MoS_(2)might efficiently improve the NRR electroactivity of SnS_(2)by the creation of Mo‐Sn‐Sn trimer catalytic sites.Otherwise,the irreversible crystal phase transition has taken place during the NRR process.Partial 1T’‐MoS_(2)and SnS_(2)have electrochemically reacted with N_(2),and irreversibly converted into Mo^(2)N and SnxNz due to the formation of Mo−N and Sn−N bonding,meanwhile,partial SnS_(2) has been irreversibly evolved into SnS due to the reduction by the power source in the electrochemical system.It would put forward a new design idea for optimizing the preparation method and electrocatalytic activity of transition metal dichalcogenides.

Prediction of Low-Permeability Reservoirs Performances Using Long and Short-Term Memory Machine Learning

In order to overcome the typical limitations of numerical simulation methods used to estimate the production of low-permeability reservoirs,in this study,a new data-driven approach is proposed for the case of water-driven hypo-permeable reservoirs.In particular,given the bottlenecks of traditional recurrent neural networks in handling time series data,a neural network with long and short-term memory is used for such a purpose.This method can reduce the time required to solve a large number of partial differential equations.As such,it can therefore significantly improve the efficiency in predicting the needed production performances.Practical examples about water-driven hypotonic reservoirs are provided to demonstrate the correctness of the method and its ability to meet the requirements for practical reservoir applications.

Selection of the appropriate reference genes by quantitative real-time PCR in leopard coral groupers Plectropomus leopardus

Leopard coral groupers(Plectropomus leopardus),commercially bred in South China,are a significant economical fish species.In this study,by means of quantitative real-time PCR(qRT-PCR)technology,we assessed the stability of six common reference genes expression and selected the appropriate reference genes in leopard coral groupers with or without Vibrio harveyi stimulation at different time points.These data produced by qRT-PCR was handled via the geNorm,NormFinder,and BestKeeper software.The results revealed all the examined reference genes had manifest tissue-specific expression in different tissues.Prior to V.harveyi stimulation,RPL13 gene was the appropriate reference gene among eleven tissue types(blood,spleen,hepatopancreas,kidney,stomach,gill,heart,skin,muscle,intestine,brain)in leopard coral groupers.Under V.harveyi stimulation,the most reliable reference genes varied from tissue to tissue and were closely hinged upon different time points.At 6-h post-bacterial injection,the appropriate reference genes in hepatopancreas,spleen,kidney,and gill were Actin,B2M,UBCE,and Actin,respectively.At 9-and 12-h post-bacterial injection,the appropriate reference genes in hepatopancreas,spleen,kidney,and gill were RPL13,Actin,Actin,and Actin,respectively.If one reference gene was preferable,RPL13,Actin,Actin,and Actin could be selected as the reference gene in hepatopancreas,spleen,kidney,and gill of leopard coral groupers after V.harveyi infection,respectively.Expression profiles of two target genes(IL-6 and NK-lysin)were used to further validate reliability of these selected appropriate candidates.This study will lay a solid foundation for the future research on qRTPCR analysis of gene expression in leopard coral groupers.

Study on the Energy Situation and Energy Policies in China

The development of socialist economy and market in China is rapid,which raises people’s demand for energy in daily life.The development of energy industry has,to a large extent,boosted the development of national economy.In the current society,in order to increase GDP in an all-round way,China should take full advantage of clean energy and economical energy in the development of energy.This thesis will analyze the energy situation and energy policies in China,in the hope of promoting the sustainable development in China.

Promoting digital twin technology application for process industry:A novel generation modelling platform and its implementations

One key concept of Industry 4.0 is the industrial digital twin(DT)-a virtual replica of physical assets,processes,and systems.DTs optimise operations,enhance productivity,and facilitate innovation across various industries,including manufacturing,energy,healthcare,and transportation.This paper presents a multi-domain and multi-time scale modelling and simulation platform,featuring built-in model libraries that represent diverse physical,chemical,and behavioural properties.A comprehensive system model-ling approach and a closed-loop industrial control system based on DTs are developed,showcasing advanced control,optimisation,and system security research capabilities.The architecture and advantages of the novel generation modelling platform are detailed,with specific applications highlighted,underscoring its contributions to the process industry.

光滑边域连续-非连续细胞自动机在裂纹开裂扩展中的应用

针对岩石裂纹开裂扩展问题,将应变光滑技术与连续-非连续细胞自动机方法相结合,构建了非连续裂纹贯穿单元和裂纹尖端单元光滑应变场,提出快速自适应光滑边域连续-非连续细胞自动机方法.构建了裂纹面位移非连续精细表征的非连续增强形函数,建立了裂纹贯穿单元和裂纹尖端单元的光滑应变矩阵求解方法,利用高斯散度定理将单元的区域积分转换为光滑域边界线积分,推导给出了光滑边域连续-非连续细胞自动机应变矩阵计算表达式,并提出了快速自适应更新方法,建立了加速因子随元胞更新而同步更新的自适应加速算法,基于此,最佳加速因子随更新自动获得,收敛速度较传统细胞自动机方法得到极大提高.利用C++编制了分析计算程序,针对多裂纹开裂扩展过程进行了模拟,并与扩展有限元进行了比较.研究发现,光滑边域连续-非连续细胞自动机方法在解的精确性、稳定性和收敛性上较扩展有限元有显著优势.

《生物多样性公约》下我国珊瑚礁养护履约进程与改善建议

珊瑚礁生态系统是《生物多样性公约》(下称《公约》)的重点保护对象。自1998年珊瑚礁出现大规模白化现象以来,珊瑚礁养护议题一直受到《公约》缔约方大会的关注。本文通过梳理我国珊瑚礁养护管理的法律法规和相关履约措施,结合海南、广西、广东三省的珊瑚礁资源变化状况,评价我国在履约方面的表现并识别存在的主要差距。研究发现,总体上我国积极采取了多种措施进行珊瑚礁的养护和管理,活珊瑚覆盖度和种类数量有一定程度的恢复,但仍存在相关立法分散、综合性治理方案缺乏、气候变化适应不足、跨部门协调机制不完善、海洋保护区管理有效性不足、资金缺乏且当地社区参与度低、珊瑚礁监测标准和规范简单且不统一、监测数据不足以进行有效评估、国际合作程度低、公众参与度不高等问题。建议我国结合履约要求,与《公约》的目标和精神基本保持一致,并考虑正在讨论的《2020后全球生物多样性保护框架》,进一步完善珊瑚礁养护立法、行动计划和气候变化适应方案,加强综合管理和协调机制建设,提升海洋保护区的管理实效性,改进珊瑚礁监测和数据采集,提升国际合作,进一步提高公众参与度,从而不断提升履约能力,构建更加完善的珊瑚礁养护体系。

The long-term prognosis and predictors of epilepsy:a retrospective study in 820 patients

Background:To investigate the prognosis and predictors for seizure control in epileptic patients in China.Methods:Eight hundred and twenty patients with epilepsy who visited Xuanwu Hospital from October 2017 to January 2020,were enrolled.The clinical information of the patients was obtained by retrospectively reviewing medical records.Prognostic measures of seizure control included remission,relapse and occurrence of drug resistance.The relationship of prognosis of seizure control with factors such as demographics,clinical characteristics and initial electroencephalography(EEG)features was investigated.Results:A total of 503(61.3%)patients experienced a 1-year remission and 330(49.3%of 669)had a 2-year remission.Idiopathic type of epilepsy(P<0.001),normal EEG(P<0.05),number of antiepileptic drugs(P<0.05)and seizure frequency of<1/month(P<0.001)at the first arrival predicted a remission independently.Of the 503 patients who achieved a 1-year remission,184(36.6%)experienced a relapse,due to external reversible causes(58 patients)or with unknown reversible triggers(126 patients).No factors were found to be associated with a relapse(P>0.05).At the end of the study,322 patients(39.3%)developed drug resistance.The development of drug resistance was associated with the following factors:symptomatic aetiology of epilepsy,epileptiform abnormality in EEG,number of antiepileptic drugs and seizure frequency of≥1/month at first arrival(P<0.001).For symptomatic epilepsy,patients with meningitis/encephalitis(P=0.007)were more likely to develop drug-resistant epilepsy than these with other causes.Conclusions:Remission is a common process.The type of epilepsy(idiopathic or symptomatic),EEG features,seizure frequency and treatment history at first arrival are related to both remission and terminal drug resistance.Among various causes of symptomatic epilepsy,meningitis/encephalitis is associated with the worst prognosis of epilepsy.

Numerical investigation on fire-induced indoor and outdoor air pollutant dispersion in an idealized urban street canyon

Fire-induced pollutant dispersion under the influence of buoyancy in urban street canyons has attracted wide attention given its adverse impact on human health.This study analyzes the influences of fire source location and crossflowing wind(perpendicular to the canyon centerline)on indoor and outdoor air pollutant dispersion in an idealized urban street canyon by employing large eddy simulation.Three fire scenarios are defined according to the transverse location of the fire source:near the windward building(scenario 1),in the middle of the canyon(scenario 2),and near the leeward building(scenario 3).Results show that a re-entrainment phenomenon appears when the wind velocity reaches a critical value in scenarios 1 and 2,but it doesn't occur in scenario 3.Fire source location significantly influences the critical re-entrainment velocity.The critical velocity in scenario 1 is approximate 1.2-1.5 m/s larger than that in scenario 2.When the heat release rate is large,the critical Fr numbers are less sensitive to changes in HRR,and remain approximately constant with values of 0.47(scenario 1)and 0.37(scenario 2).When the wind velocity is large,more compartments are expected to be affected in the upper floors in all of the three scenarios,and smoke is distributed in an inverted triangle within the buildings.The indoor/outdoor temperature and pollutant concentrations are also analyzed.Our findings can provide valuable information for both human and property safety in relation to urban street canyons and their surrounding buildings.

Palladium-Catalyzed Regioselective Asymmetric Chemodivergent Allylation of Oxazolones with Morita-Baylis-Hillman Adducts

Oxazolones are structural subunits in numerous natural products and designed molecules with substantial pharmacological properties.Here,a palladium-catalyzed chemodivergent regio-and enantioselective allylic alkylation of 4-or 5-substituted oxazol-2(3H)-ones with Morita-Baylis-Hillman(MBH)adducts has been developed using a spiroketal-based diphosphine as the ligand(50 examples).Interestingly,4-substituted oxazol-2(3H)-ones acted as a C-nucleophiles in the reaction to afford a range of chiral 4,5-substituted oxazol-2(3H)-ones in high yields(72-99%)with good to excellent chemo-,regio-,and enantioselectivities(C/N 95:5->99:1,b/l 91:9->99:1,85-98%ee).When a N-nucleophile was used under otherwise identical conditions,5-substituted oxazol-2(3H)-ones delivered a range of chiral 3,5-substituted oxazol-2(3H)-ones in high yields(68-98%)with good regio-and enantioselectivities(b/l 71:29-91:9,66-94%ee).The synthesis can be readily performed on gram scale under fairly low catalyst loadings,and the utility of the protocol was showcased in the facile transformation of the products into more elaborate chiral molecules.

Enhanced thermal performance from liquid metal in copper/graphite filled elastomer

With the increasing integration level of modern electronics,thermal management becomes an urgent issue for guaranteeing the work efficiency and lifespan of electronics.On the basis of intrinsic high thermal conductivity nature,highly ordered graphite and copper stripes are densely aligned in the silicone gel pads in vertical(VCuGr)and oblique(@15°CuGr)directions to couple the high thermal conductivity and mechanical softness.The wetting nature of liquid metal(LM)on the chemically treated Cu surface is utilized to form a LM layer on the two surfaces of thermal pads.The obtained LM-pad TIMs possessed ultrahigh through-plane thermal conductivity(VCuGr:71.4 W/(m K),@15°CuGr:62.5 W/(m K))under the normal packaging pressure.The thermal resistance decreased from 0.69 cm^(2) K/W to 0.25 cm^(2) K/W with the surface modification with LM.Theoretical simulation and practical thermal dissipation test results further demonstrate the excellent thermal management capability of these composites in high-power electronics.

Rational design, synthesis, and biological evaluation of novel C6-modified geldanamycin derivatives as potent Hsp90 inhibitors and anti-tumor agents

Heat shock protein 90(Hsp90) is an appealing anticancer drug target that provoked a tremendous wave of investigations. Geldanamycin(GA) is the first identified Hsp90 inhibitor that exhibited potent anticancer activity, but the off-target toxicity associated with the benzoquinone moiety hampered its clinical application. Until now, structure optimization of GA is still in need to fully exploit the therapeutic value of Hsp90. Due to the structural complexity and synthetic challenge of this compound family, conventional optimization is bound to be costly but high efficiency is expected to be reachable by combining the art of rational design and total synthesis. Described in this paper is our first attempt at this approach aiming at rational modification of the C6-position of GA. The binding affinities towards Hsp90 of compound 1(C6-ethyl) and 2(C6-methyl) were designed and predicted by using Discovery Studio. These compounds were synthesized and further subjected to a thorough in vitro biological evaluation. We found that compounds1 and 2 bind to Hsp90 protein with the IC_(50) of 34.26 nmol/L and 163.7 nmol/L, respectively. Both compounds showed broad-spectrum antitumor effects. Replacing by ethyl, compound 1 exhibited more potent bioactivity than positive control GA, such as in G2/M cell cycle arrest, cell apoptosis and client proteins degradations. The results firstly indicated that the docking study is able to provide a precise prediction of Hsp90 affinities of GA analogues, and the C6 substituent of GA is not erasable without affecting its biological activity.

Highly efficient synthesis of boron nitride nanotubes by catalytic chemical vapor deposition of boron/nickel containing precursors

High-purity and high-yield boron nitride nanotubes with large aspect ratio were prepared by a facile two-step process,including the synthesis of boron/nickel containing precursors by precipitation reactions and subsequent thermally catalytic chemical vapor deposition reactions.The influence of catalyst content and annealing temperature on the phase composition and microstructure of the products were investigated.The results show that it is difficult to exert the catalytic effect of nickel-based catalyst at low temperatures(<1400℃).At appropriate temperatures(1400-1500℃),highly crystalline boron nitride nanotubes with a length of more than 50 mm and a diameter of 50 nm are formed.The content of catalyst in the precursor mainly affects the morphology of the boron nitride product.If the content is too low,it is easy to form boron nitride particles;while high catalyst content can easily lead to catalyst aggregation and form a submicron one-dimensional boron nitride with unregular structure.Based on microstructural evolutions,phase changes,and thermodynamic analysis,the vapor-liquid-solid(V-L-S)growth mechanism of the tip growth mode dominates the formation of boron nitride nanotubes has also been verified.