End-group modulation of phenazine based non-fullerene acceptors for efficient organic solar cells with high open-circuit voltage

Phenazine-based non-fullerene acceptors(NFAs)have demonstrated great potential in improving the power conversion efficiency(PCE)of organic solar cells(OSCs).Halogenation is known to be an effective strategy for increasing optical absorption,refining energy levels,and improving molecular packing in organic semiconductors.Herein,a series of NFAs(Pz IC-4H,Pz IC-4F,Pz IC-4Cl,Pz IC-2Br)with phenazine as the central core and with/without halogen-substituted(dicyanomethylidene)-indan-1-one(IC)as the electron-accepting end group were synthesized,and the effect of end group matched phenazine central unit on the photovoltaic performance was systematically studied.Synergetic photophysical and morphological analyses revealed that the PM6:Pz IC-4F blend involves efficient exciton dissociation,higher charge collection and transfer rates,better crystallinity,and optimal phase separation.Therefore,OSCs based on PM6:Pz IC-4F as the active layer exhibited a PCE of 16.48%with an open circuit voltage(Voc)and energy loss of 0.880 V and 0.53 e V,respectively.Accordingly,this work demonstrated a promising approach by designing phenazine-based NFAs for achieving high-performance OSCs.

Blood glucose-lowering activity of protocatechuic acid is mediated by inhibiting a-glucosidase

α-Glucosidase inhibitors are effective in controlling postprandial hyperglycemia,which play crucial roles in the management of type 2 diabetes.Protocatechuic acid(PCA)is one of phenolic acids existing not only in various plant foods but also as a major microbial metabolite of dietary anthocyanins in the large colon.The present study investigated the inhibitory mechanism of PCA on a-glucosidase in vitro and examined its effect on postprandial blood glucose levels in vivo.Results from in vitro experiments demonstrated that PCA was a mix-type inhibitor of a-glucosidase.Driven by hydrogen bonds and van der Waals interactions,PCA reversibly bound withα-glucosidase to form a stable a-glucosidase-PCA complex in a spontaneous manner.The computational simulation found that PCA could insert into the active cavity of a-glucosidase and establish hydrogen bonds with catalytic amino acid residues.PCA binding aroused the steric hindrance for substrates to enter active sites and caused the structural changes of interacted catalytic amino acid residues.PCA also exhibited postprandial hypoglycemic capacity in diabetic mice.This study may provide the theoretical basis for the application of PCA as an active ingredient of functional foods in dietary management of diabetes.

Molecular packing tuning via chlorinated end group enables efficient binary organic solar cells over 18.5%

Designing novel nonfullerene acceptors(NFAs)is of vital importance for the development of organic solar cells(OSC).Modification on the side chain and end group are two powerful tools to construct efficient NFAs.Here,based on the high-performance L8BO,we selected 3-ethylheptyl to substitute the inner chain of 2-ethylhexyl,obtaining the backbone of BON3.Then we introduced different halogen atoms of fluorine and chlorine on 2-(3-oxo-2,3-dihydro-1Hinden-1-ylidene)malononitrile end group(EG)to construct efficient NFAs named BON3-F and BON3-Cl,respectively.Polymer donor D18 was chosen to combine with two novel NFAs to construct OSC devices.Impressively,D18:BON3-Cl-based device shows a remarkable power conversion efficiency(PCE)of 18.57%,with a high open-circuit voltage(V_(OC))of 0.907 V and an excellent fill factor(FF)of 80.44%,which is one of the highest binary PCE of devices based on D18 as the donor.However,BON3-F-based device shows a relatively lower PCE of 17.79%with a decreased FF of 79.05%.The better photovoltaic performance is mainly attributed to the red-shifted absorption,higher electron and hole mobilities,reduced charge recombination,and enhanced molecular packing in the D18:BON3-Cl films.Also,we performed stability tests on two binary systems;the D18:BON3-Cl and D18:BON3-F devices maintain 88.1%and 85.5%of their initial efficiencies after 169 h of storage at 85°C in an N2-filled glove box,respectively.Our work demonstrates the importance of selecting halogen atoms on EG and provides an efficient binary system of D18:BON3-Cl for further improvement of PCE.

Why does a high-fat diet induce preeclampsia-like symptoms in pregnant rats?

Changes in neurotransmitter levels in the brain play an important role in epilepsy-like attacks after pregnancy-induced preeclampsia-eclampsia. Metabotropic glutamate receptor 1 participates in the onset of lipid metabolism disorder-induced preeclampsia. Pregnant rats were fed with a high-fat diet for 20 days. Thus, these pregnant rats experienced preeclampsia-like syndromes such as hyper-tension and proteinuria. Simultaneously, metabotropic glutamate receptor 1 mRNA and protein ex-pressions were upregulated in the rat hippocampus. These findings indicate that increased expres-sion of metabotropic glutamate receptor 1 promotes the occurrence of high-fat diet-induced pree-clampsia in pregnant rats.

Full-Blind Delegating Private Quantum Computation

The delegating private quantum computation(DQC)protocol with the universal quantum gate set{X,Z,H,P,R,CNOT}was firstly proposed by Broadbent et al.[Broadbent(2015)],and then Tan et al.[Tan and Zhou(2017)]tried to put forward a half-blind DQC protocol(HDQC)with another universal set{H,P,CNOT,T}.However,the decryption circuit of Toffoli gate(i.e.T)is a little redundant,and Tan et al.’s protocol[Tan and Zhou(2017)]exists the information leak.In addition,both of these two protocols just focus on the blindness of data(i.e.the client’s input and output),but do not consider the blindness of computation(i.e.the delegated quantum operation).For solving these problems,we propose a full-blind DQC protocol(FDQC)with quantum gate set{H,P,CNOT,T},where the desirable delegated quantum operation,one of{H,P,CNOT,T},is replaced by a fixed sequence(H,P,CZ,CNOT,T)to make the computation blind,and the decryption circuit of Toffoli gate is also optimized.Analysis shows that our protocol can not only correctly perform any delegated quantum computation,but also holds the characteristics of data blindness and computation blindness.

Highly efficient ternary organic solar cells with excellent open-circuit voltage and fill factor via precisely tuning molecular stacking and morphology

The micro-morphology and molecular stacking play a key role in determining the charge transport process and nonradiative energy loss, thus impacting the performances of organic solar cells(OSCs). To address this issue, a non-fullerene acceptor PhC6-IC-F with alkylbenzene side-chain, possessing optimized molecular stacking, complementary absorption spectra and forming a cascade energy level alignment in the PM6:BTP-eC9 blend, is introduced as guest acceptor to improve efficiency of ternary OSCs. The bulky phenyl in the side-chain can regulate crystallinity and optimizing phase separation between receptors in ternary blend films, resulting in the optimal phase separations in the ternary films. As a result, high efficiencies of 18.33% as photovoltaic layer are obtained for PhC6-IC-F-based ternary devices with excellent fill factor(FF) of 78.92%. Impressively, the ternary system produces a significantly improved open circuit voltage(V_(oc)) of 0.857 V compared with the binary device,contributing to the reduced density of trap states and suppressed non-radiative recombination result in lower energy loss. This work demonstrates an effective approach for adjusting the aggregation, molecular packing and fine phase separation morphology to increase V_(oc) and FF, paving the way toward high-efficiency OSCs.

嫦娥五号最快速冷却年轻月海玄武岩的结晶动力学

我国嫦娥五号任务在月球风暴洋北部采集到了迄今为止最年轻的月海玄武岩并成功返回.研究这些年轻月海玄武岩的岩相学特征和冷却速率对于揭示月球熔岩流的结构剖面和就位情况具有重要科学意义.本文利用扫描电子显微镜和电子探针技术对一个嫦娥五号玄武质岩屑(CE5C0800YJYX005GP)进行了详细的岩相学和矿物学研究,并利用晶体粒径分布和热力学模拟恢复了该样品的冷却速率.结果表明,该样品的辉石具有高和低切尔马克组分的两个成分分区,指示开始结晶时30~50℃的高过冷度条件;钛铁矿和斜长石的晶体粒径分布指示152~189℃/h的快速冷却条件和5.7~6.3 cm的埋藏深度,使得该样本成为迄今为止所报道的最快速冷却、最接近熔岩流表面的嫦娥五号玄武岩.结合先前对其他嫦娥五号样本的冷却速率研究,重建了嫦娥五号熔岩流的结构剖面和就位模型.该模型表明嫦娥五号玄武岩母岩浆比阿波罗玄武岩母岩浆的去气程度更低,有利于熔岩流热量的维持,从而有利于在月球表面形成超长月溪.

Iterative Android automated testing

With the benefits of reducing time and workforce,automated testing has been widely used for the quality assurance of mobile applications(APPs).Compared with automated testing,manual testing can achieve higher coverage in complex interactive Activities.And the effectiveness of manual testing is highly dependent on the user operation process(UOP)of experienced testers.Based on the UOP,we propose an iterative Android automated testing(IAAT)method that automatically records,extracts,and integrates UOPs to guide the test logic of the tool across the complex Activity iteratively.The feedback test results can train the UOPs to achieve higher coverage in each iteration.We extracted 50 UOPs and conducted experiments on 10 popular mobile APPs to demonstrate IAAT’s effectiveness compared with Monkey and the initial automated tests.The experimental results show a noticeable improvement in the IAAT compared with the test logic without human knowledge.Under the 60 minutes test time,the average code coverage is improved by 13.98%to 37.83%,higher than the 27.48%of Monkey under the same conditions.

Inner alkyl chain modulation of small molecular acceptors enables molecular packing optimization and efficient organic solar cells

With the generation of Y6,organic solar cells have reached remarkable achievement of over 19%efficiency.Alkyl chain is of importance to modulate intermolecular stacking and possibly enhance optoelectronic properties of small molecule acceptors(SMAs).Three alkyl chains of 2-ethylhexyl,2-butylocyl and 3-ethylheptyl were selected to obtain G6-EH,G6-BO and G6-EHep molecules,respectively.Compared to G6-EH and G6-BO,G6-EHep was found inducing unfavourable large domain size.Furthermore,we discover that 2-butyloctyl effectively inhibits monomolecular and bimolecular recombination,improves molecular packing,generates more balanced carrier mobility and enhances exciton dissociation.The SMA with 2-butyloctyl alkyl chains(G6-BO)shows the best electrical and morphological characteristics,achieving a higher power conversion efficiency(PCE)of 17.06%,with an open circuit voltage of 0.912 V,a short-circuit current of 24.22 m A cm-2and a fill factor of 77.25%.Finally,using the ternary strategy by incorporating the G6-BO acceptor into PM6:BTP-e C9,we achieved a higher PCE of18.13%with enhanced electron transport.

Predicting the utilization factor of blasthole in rock roadways by random forest

The utilization factor of blasthole is a crucial indicator of the effectiveness of blasting in rock roadways.A significant value means that the explosive energy is fully utilized,the single-cycle advance is high,and the excavation rate is fast.A good blasting programme is a prerequisite for improving the utilization rate and predicting the utilization rate before blasting operations can verify the feasibility of the blasting programme.Firstly,a database of rock roadway blasting covering different geological and production conditions is estab-lished.Secondly,error analysis and the Gini coefficient method are used to weight the characteristic variables,quantify the importance of the variables and identify eight key indicators affecting the blasting hole utilization rate.Then,a random forest algorithm-based model for predicting utilization factor of blasthole is proposed,and the results of the model on the test set are:root mean square error(RMSE)is 0.0137,mean absolute error(MAE)is 0.0087,and coefficient of determination(R^(2))is 0.905.The performance of this method is com-pared with that of the neural network and support vector machine models on the test sets to verify the superiority of the random forest algorithm.Finally,to verify the generalization ability and practicality of the random forest prediction model,the model is applied to the rock roadway blasting construction of Gu Bei coal mine in Anhui Province.The results show that R2 is 0.913,so the model is reliable and accurate,which can meet the actual engineering requirements and lay the foundation for the promotion and application of this technology.

现代汉语“语用数”的种类及其确定

在'语用数'研究中,可以从不同的维度对其分类:一是根据名词性成分参与事件的方式到底是必须的还是必要的,区分出充分数和必要数;二是根据参与事件的实体维度的不同,区分出空间分割的语用数、时间分割的语用数、功能分割的语用数和特征分割的语用数。在以上分析的基础上,本文主要从时间角度对语用数进行考察,同时也对相关的语言现象作了一定的解释。

地震超材料:从自然结构到新型人工结构

光子晶体、声子晶体和声学超材料在调控波和波衰减等领域产生了深远影响.它们并不是自然界中新发现的材料,而是根据不同需求设计的复合结构,通常利用布拉格散射或局域共振机理来达到调控声波/弹性波能带结构的目的.与光子晶体不同,声子晶体和声学超材料的工作区域在较低频区域,因此获得低频且大范围的禁带是该领域的研究重点,并逐渐拓展到频率低、波长长的地震波隔震减灾防控上.本文从纳米光子和地震超材料的联系出发,从固体物理的视角分析了地震超材料的城市群、自然森林超材料等,将新型人工地震超材料在分布区域、禁带机制、实验方式3个方面进行了分类比较,并展望了现阶段地震超材料研究的一些局限性以及面临的挑战.

MXene在电化学传感器中的应用

过渡金属碳化物或氮化物(MXene)作为一种新型的二维层状材料,由于具有良好的导电性、水中分散性、高的生物相容性和稳定性等,在电化学传感领域具有巨大的应用潜力。将MXene与其他纳米材料复合,可以扬长避短,在性能上实现优势协同和功能互补,有效提高电化学传感器的灵敏度和选择性。本文按照检测物的种类进行分类,综述了基于MXene材料构建的电化学传感平台在生物标记物和环境污染物检测中的应用,并讨论了MXene材料在电化学传感领域未来研究发展和应用中所面临的挑战。

Automatic test report augmentation to assist crowdsourced testing

In crowdsourced mobile application testing, workers are often inexperienced in and unfamiliar with software testing. Meanwhile, workers edit test reports in descriptive natural language on mobile devices. Thus, these test reports generally lack important details and challenge developers in understanding the bugs. To improve the quality of inspected test reports, we issue a new problem of test report augmentation by leveraging the additional useful information contained in duplicate test reports. In this paper, we propose a new framework named test report augmentation framework (TRAF) towards resolving the problem. First, natural language processing (NLP) techniques are adopted to preprocess the crowdsourced test reports. Then, three strategies are proposed to augment the environments, inputs, and descriptions of the inspected test reports, respectively. Finally, we visualize the augmented test reports to help developers distinguish the added information. To evaluate TRAF, we conduct experiments over five industrial datasets with 757 crowdsourced test reports. Experimental results show that TRAF can recommend relevant inputs to augment the inspected test reports with 98.49% in terms of NDCG and 88.65% in terms of precision on average, and identify valuable sentences from the descriptions of duplicates to augment the inspected test reports with 83.58% in terms of precision, 77.76% in terms of recall, and 78.72% in terms of F-measure on average. Meanwhile, empirical evaluation also demonstrates that augmented test reports can help developers understand and fix bugs better.

18.01%Efficiency organic solar cell and 2.53%light utilization efficiency semitransparent organic solar cell enabled by optimizing PM6:Y6 active layer morphology

Optimizing the photoactive layer morphology is a simple,promising way to improve the power conversion efficiencies(PCEs)of organic solar cells(OSCs).Here,we compared different post-processing treatments on PM6:Y6 blend films and relevant effects on device performances,including as-cast,thermal annealing and solvent annealing.This solvent annealing processes can effectively improve the vertical distribution and aggregation of polymer donors and small molecule acceptors,then optimize the active layer film morphology,ultimately elevating PCE.Thus,one of champion efficiencies of 18.01%was achieved based on the PM6:Y6 binary OSCs.In addition,a relatively high light utilization efficiency(2.53%)was achieved when a transparent electrode made of Cu(1 nm)and Ag(15 nm)was utilized to fabricate a semitransparent OSC with a remarkable PCE of 13.07%and 19.33%average visible-light transmittance.These results demonstrated that carefully optimizing morphology of active layer is conducive to achieving a high-performance OSC.