Designing simple non-fused terthiophene-based electron acceptors for efficient organic solar cells

Low-cost photovoltaic materials are essential for realizing large-scale commercial applications of organic solar cells(OSCs).However,highly efficient OSCs based on low-cost photovoltaic materials are scarce due to a deficiency in understanding the structure-property relationship.Herein,we investigated two low-cost terthiophene-based electron acceptors,namely,3TC8 and 3TEH,with 3,4-bis(octan-3-yloxy)thiophene,differing only in the alkylated thiophene-bridges.Both acceptors exhibit low optical gaps(∼1.43 eV)and possess deep highest occupied molecular orbital(HOMO)levels(∼−5.8 eV).Notably,the single-crystal structure of 3TEH demonstrates highly planar conjugated backbone and strongπ-πstacking between intermolecular terminal groups,attributed to the presence of the bulky alkylated noncovalently conformational locks.Upon utilizing both acceptors to fabricate OSCs,the 3TC8-based device exhibited a power conversion efficiency(PCE)of 11.1%,while the 3TEH-based OSC demonstrated an excellent PCE of 14.4%.This PCE is the highest among OSCs based on terthiophene-containing electron acceptors.These results offer a new strategy for designing low-cost electron acceptors for highly efficient OSCs.

Performance of Gas-Steam Combined Cycle Cogeneration Units Influenced by Heating Network Terminal Steam Parameters

The determination of source-side extracted heating parameters is of great significance to the economic operation of cogeneration systems.This paper investigated the coupling performance of a cogeneration heating and power system multidimensionally based on the operating characteristics of the cogeneration units,the hydraulic and thermodynamic characteristics of the heating network,and the energy loads.Taking a steam network supported by a gas-steam combined cycle cogeneration system as the research case,the interaction effect among the source-side prime movers,the heating networks,and the terminal demand thermal parameters were investigated based on the designed values,the plant testing data,and the validated simulation.The operating maps of the gas-steam combined cycle cogeneration units were obtained using THERMOFLEX,and the minimum source-side steam parameters of the steam network were solved using an inverse solution procedure based on the hydro-thermodynamic coupling model.The cogeneration operating maps indicate that the available operating domain considerably narrows with the rise of the extraction steam pressure and flow rate.The heating network inverse solution demonstrates that the source-side steam pressure and temperature can be optimized from the originally designed 1.11 MPa and 238.8°C to 1.074 MPa and 191.15°C,respectively.Under the operating strategy with the minimum source-side heating parameters,the power peak regulation depth remarkably increases to 18.30%whereas the comprehensive thermal efficiency decreases.The operation under the minimum source-side heating steam parameters can be superior to the originally designed one in the economy at a higher price of the heating steam.At a fuel price of$0.38/kg and the power to fuel price of 0.18 kg/(kW·h),the critical price ratio of heating steam to fuel is 119.1 kg/t.The influence of the power-fuel price ratio on the economic deviation appears relatively weak.

新工科项目“地方(行业)高校化学类专业应对产业变化的升级改造研究与实践”的实施

"新工科"项目"地方(行业)高校化学类专业应对产业变化的升级改造研究与实践"是教育部首批新工科项目。本项目针对地方和行业高校化学类专业如何应对产业变化而开展专业升级改造的问题,进行了深入的调查研究,分析了"新工科"对人才的能力要求,提出了适应未来要求的专业人才培养目标、毕业要求和新的培养模式,总结了部分高校化学类专业开展"新工科"建设的经验。

Novel cobalt-free tantalum-doped perovskite Ba Fe_(1-y)Ta_yO_(3-δ)with high oxygen permeation

Cobalt-free perovskite-type oxides BaFel_yTayO3-6 （0 _〈 y -〈 0.2） were synthesized via a simple solid state reac- tion. The cubic perovskite structure can be obtained when y is over 0.1. BaFeo.Ta0.lO3-6 （BFT0.1） membrane shows the highest oxygen permeation flux, which can reach 1.6 ml. min- 1. cm-2 at 950 ℃ under the gradient of air/He. The O2-TPD results reveal that BaFe0.9Ta0.lO3-a material shows an excellent reversibility and phase structure stability in air. The oxygen permeation flux is limited by the bulk diffusion when the membrane thick- ness is over 0.8 mm, and it is limited by both the bulk diffusion and the surface exchange when the membrane thickness is below 0.5 mm. Stable oxygen permeation fluxes are obtained during 180 h operation.

Effects of Slow-release Fertilizers and Sugarcane-specific Fertilizers on Yield and Quality of Sugarcane

The effects of slow-release fertilizers and sugarcane-specific fertilizers on the growth and quality of sugarcane were studied to provide a theoretical basis for cultivation of sugarcane with lower costs but higher efficiency. Field experiments were carried out in two major sugarcane areas in Guangxi and three fertilization treatments were studied: single application of compound fertilizers( treatment I),compound fertilizers + slow-release fertilizers( treatment II) and sugarcane-specific base fertilizers + sugarcane-specific topdressing( treatment III). Effects of equal fertilization conditions of treatment I,II and III on growth,yield and sugar of sugarcane were studied. The three fertilization treatments had little effects on emergence,tillering,and effective stems of sugarcane,but compared with the treatment of compound fertilizer( treatment I) with a ratio of N,P,and K of 1∶1∶1,treatment II using slow-release fertilizers as topdressing had better growth,higher plant height and stem diameter,so the yield was higher. Treatment III designed sugarcane-specific fertilizers with proper ratio according to fertilizer demands of sugarcane. Besides,the treatment III sugarcane-specific base fertilizers,containing certain amount of organic matters,could promote the sugar accumulation of sugarcane. Therefore,the sugarcane yield of treatment III was higher than that of treatment II. In conclusion,slow-release fertilizers and sugarcane-specific fertilizers can significantly increase sugarcane yield,especially sugarcane-specific fertilizers. Sugarcane-specific fertilizers have reasonable ratio and contain certain amount of organic matters,and can increase sugar content,obtain significant economic benefits,so it is worth popularization in large areas.

Formation of nano-twinned 3C-SiC grains in Fe-implanted 6H-SiC after 1500-℃annealing

A nano-twinned microstructure was found in amorphous SiC after high-temperature annealing.Grazing incidence x-ray diffraction,high-resolution transmission electron microscopy,and electron diffraction were performed to characterize the microstructure and phase transition in the recrystallization layer.After 1500℃or 2-h annealing,3C-SiC grains and numerous stacking faults on the{111}planes were visible.Some 3C-SiC grains have nano-twinned structure with{011}planes.Between the nano-twinned 3C-SiC grains,there is a stacking fault,indicating that the formation mechanisms of the nano-twinned structure are related to the disorder of Si atoms.The increase in the twin thickness with increasing annealing temperature demonstrates that the nano-twinned structure can sink for lattice defects,in order to improve the radiation tolerance of SiC.

Current Development and Prospects of Selenium-enriched Moringa oleifera Industry in Guangxi

Due to its unique economic value,Moringa oleifera Lam. has become a tree species with great development potential. This paper firstly introduced the value of development and utilization of M. oleifera in nutrition,medicinal,industrial,greening,etc. Then,focusing on the current development status of M. oleifera industry in Guangxi and combining Guangxi's resource conditions,it came up with recommendations for the comprehensive development and rational utilization of M. oleifera. Besides,it made a prediction of the prospect of Se-enriched M.oleifera industry in Guangxi.

Extrapolation over temporal knowledge graph via hyperbolic embedding

Predicting potential facts in the future,Temporal Knowledge Graph(TKG)extrapolation remains challenging because of the deep dependence between the temporal association and semantic patterns of facts.Intuitively,facts(events)that happened at different timestamps have different influences on future events,which can be attributed to a hierarchy among not only facts but also relevant entities.Therefore,it is crucial to pay more attention to important entities and events when forecasting the future.However,most existing methods focus on reasoning over temporally evolving facts or mining evolutional patterns from known facts,which may be affected by the diversity and variability of the evolution,and they might fail to attach importance to facts that matter.Hyperbolic geometry was proved to be effective in capturing hierarchical patterns among data,which is considered to be a solution for modelling hierarchical relations among facts.To this end,we propose ReTIN,a novel model integrating real-time influence of historical facts for TKG reasoning based on hyperbolic geometry,which provides low-dimensional embeddings to capture latent hierarchical structures and other rich semantic patterns of the existing TKG.Considering both real-time and global features of TKG boosts the adaptation of ReTIN to the ever-changing dynamics and inherent constraints.Extensive experiments on benchmarks demonstrate the superiority of ReTIN over various baselines.The ablation study further supports the value of exploiting temporal information.

Isolation and Identification of Selenium-tolerant Strains from Selenium-rich Soil in Guangxi

To provide reference for selenium resource exploitation of soil,many selenium-tolerant strains were isolated from selenium-rich soil in Guangxi. The dilution spread plate method and selenium-added culture method were used to screen the selenium-tolerant strains from the soils which were sampled from the main Selenium-rich areas such as Yongfu,Bama,Yulin Hanshan,Guiping and Tengxian. The results showed that 8 strains with high selenium tolerance were obtained,which could tolerate the selenium concentration above 10 000 μg/m L in solid medium. Among the 8 strains,YLB1-33 showed the highest selenium tolerance,and it could still grow weakly in the solid medium with selenium concentration of 29 000 μg/m L. The sequencing of 16 S rD NA and phylogenetic analysis showed that YLB1-6 was identified as Bacillus cereus,BMB2-1 and TXB1-8 were identified as Bacillus pumilus,GPB2-5 was identified as Bacillus thuringiensis,YLB1-26 and YLB1-33 were identified as Bacillus licheniformis,and YLB1-2 and YFB1-8 were identified as Serratia marcescens. The finding of selenium-tolerance strains had potential application value on promoting the utilization of selenium soil resources and the development of selenium-rich agricultural products in Guangxi.

Study on Extraction Method of Selenium-enriched Rice

[Objectives] The aims were to optimize the extraction process of selenoproteins from selenium-enriched rice in Guangxi and provide references for the intensive processing and comprehensive utilization of selenium protein resources. [Methods]Selenium-enriched rice was used as materials to extract selenoproteins by phosphate buffer extraction method and to optimize the extraction process of selenoproteins by using the orthogonal experiment. Proteins and selenium content was measured by Coomassie Brilliant Blue G-250 reagent and AFS（ atomic fluorescence spectrometry） respectively. [Results] The most significant factor affecting extraction of rice Selenoproteins was extraction NaO H concentration,followed by the ratio of solid-liquid,temperature and then extraction time. The optimum extraction conditions of selenoproteins from rice were extraction temperature of 50 ℃,NaO H concentration of 0. 14 mol/L,extraction time of 5 h,and solid-liquid ratio of 1∶ 30. [Conclusions]The alkali extraction process optimized by orthogonal test could effectively improve the extraction rate of selenoproteins,and the optimized process parameters could be popularized and applied in practical production.

In掺杂对PbTe薄膜结构及电输运特性影响

本文采用分子束外延(MBE)方法在BaF2(111)衬底上外延生长了Pb1-xInxTe (0.00 ≤ x ≤ 0.20)薄膜。研究结果表明当x ≤ 0.06时,In在PbTe中进行替位式掺杂,形成n型的立方相Pb1?xInxTe结构,薄膜电导率随In掺杂量的增加而增大;当x ≥ 0.10时,In掺杂出现过饱和,过量的In形成In2Te3结构相,Pb1-xInxTe薄膜电导率急剧下降。整个掺杂过程中,In均向薄膜表面发生了偏析。综合分析不同In掺杂量下Pb1-xInxTe薄膜的Seebeck系数和电导率测试结果,可以得出In的微量掺杂可实现PbTe薄膜电输运性能的提升,In掺杂量为0.06时薄膜表现出最佳的电输运性能,440K时Pb1-xInxTe (x = 0.06)的功率因子可达9.7 μW-cm-1`K-2,为本征PbTe最大功率因子的1.2倍。

Surface chemical disorder and lattice strain of GaN implanted by 3-MeV Fe^(10+)ions

Chemical disorder on the surface and lattice strain in GaN implanted by Fe^(10+)ions are investigated.In this study,3-MeV Fe^(10+)ions fluence ranges from 1×10^(13)ions/cm^(2)to 5×10^(15)ions/cm^(2)at room temperature.X-ray photoelectron spectroscopy,high-resolution x-ray diffraction,and high-resolution transmission electron microscopy were used to characterize lattice disorder.The transition of Ga-N bonds to oxynitride bonding is caused by ion sputtering.The change of tensile strain out-of-plane with fluence was measured.Lattice disorder due to the formation of stacking faults prefers to occur on the basal plane.

Comparison of cavities and extended defects formed in helium-implanted 6H-SiC at room temperature and 750 ℃

The formation of cavities in silicon carbide is vitally useful to“smart-cut”and metal gettering in semiconductor industry.In this study,cavities and extended defects formed in helium(He)ions implanted 6H-SiC at room temperature(RT)and 750℃ followed by annealing at 1500℃are investigated by a combination of transmission electron microscopy and high-resolution electron microscopy.The observed cavities and extended defects are related to the implantation temperature.Heterogeneously distributed cavities and extended defects are observed in the helium-implanted 6H-SiC at RT,while homogeneously distributed cavities and extended defects are formed after He-implanted 6H-SiC at 750℃.The possible reasons are discussed.

Effect of helium concentration on irradiation damage of Fe-ion irradiated SIMP steel at 300℃and 450℃

SIMP steel is newly developed fully martensitic steel for lead-cooled fast reactors and accelerator-driven systems.It is important to evaluate its radiation resistance via high flux neutron irradiation,where dense He atoms can be formed via(n,α)transmutation reaction.Co-irradiation with Fe and He ions,instead of neutron,was performed.Specimens were irradiated with 6.4-MeV Fe ions to the damage dose of 5 dpa at a depth of 600 nm.Three different helium injection ratios of 60-appm He/dpa(dpa:displacements per atom),200-appm He/dpa and 600-appm He/dpa at a depth of 600 nm,were performed.Two different irradiation temperatures of 300℃and 450℃were carried out.The effect of helium concentration on the microstructure of Fe-irradiated SIMP steel was investigated.Microstructural damage was observed using transmission electron microscopy.The formed dislocation loops and bubbles depended on the helium injection ratio and irradiation temperature.Lots of dislocation loops and helium bubbles were homogeneously distributed at 300℃,but not at 450℃.The causes of observed effects are discussed.

Optical spectroscopy study of damage evolution in 6H-SiC by H_(2)^(+)implantation

Lattice defects induced by ion implantation into SiC have been widely investigated in the decades by various techniques.One of the non-destructive techniques suitable to study the lattice defects in SiC is the optical characterization.In this work,confocal Raman scattering spectroscopy and photoluminescence spectrum have been used to study the effects of 134-keV H_(2)^(+)implantation and thermal treatment in the microstructure of 6H-SiC single crystal.The radiation-induced changes in the microstructure were assessed by integrating Raman-scattering peaks intensity and considering the asymmetry of Raman-scattering peaks.The integrated intensities of Raman scattering spectroscopy and photoluminescence spectrum decrease with increasing the fluence.The recovery of the optical intensities depends on the combination of the implantation temperature and the annealing temperature with the thermal treatment from 700℃to 1100℃.The different characterizations of Raman scattering spectroscopy and photoluminescence spectrum are compared and discussed in this study.

Oxidation behavior of Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C-M_(x)C(M=Ti,Zr,Hf,Nb,Ta) composite ceramic at high temperature

Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C-M_(t)C composite ceramic was prepared by hot press sintering,with the Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C high-entropy carbide as the main phase.Secondary phase M_(x)C(M=Ti,Zr,Hf,Nb,Ta) was found to be distributed relatively uniform in the composite ceramic.The oxidation behavior of the ceramic was examined after exposure to 923 K and 1173 K.Morphology of the surface and cross sections of all oxidation samples were observed.The characteristics of the oxidation behavior of the high-entropy carbide and the secondary phase M_(x)C were compared and analyzed.The secondary phases(such as Ti-rich carbide or Hf-rich carbide) in the material were seriously oxidized at 923 K and 1173 K,which reflects the superior oxidation performance of the high-entropy carbide.The nano high-entropy oxides with Ti,Zr,Hf,Nb,Ta,and O elements were discovered by oxidation of the composite ceramic.This research will help deepen the understanding of the oxidation mechanism of high-entropy carbide and composite ceramic.

Comparison of helium bubble formation in F82H, ODS, SIMP and T91 steels irradiated by Fe and He ions simultaneously

Ferritic-martensitic steels and ODS steels are attractive candidates for structural materials in advanced nuclear-power systems due to their good swelling resistance. Four kinds of steels, F82 H, 15 Cr-ODS, SIMP and T91, are investigated in this study. We take 6.4 Me V Fe3+ ions and energy-degraded 1.0 Me V He+ ions in the irradiation of these materials to 5 dpa and 60 appm He/dpa, 200 appm He/dpa and 600 appm He/dpa at 300℃ and 450℃, respectively. The bubble formation and distribution are investigated by transmission electron microscopy(TEM). Formation and distribution of the bubbles in the four investigated steels are compared. The influence of irradiation temperature and helium injection ratio on bubble formation is discussed. It is found that there appears to be homogenously distributed bubbles at 300℃ irradiation while heterogeneously distributed bubbles at 450℃ irradiation.

Comparison of Cavities Formed in Single Crystalline and Polycrystalline α-SiC after H Implantation

Cavities and extended defects formed in single crystalline and polycrystalline α-SiC implanted with H+ions are compared.The samples are investigated by cross-sectional transmission electron microscopy.H2 bubbles are formed during H implantation and H2 molecules escape the sample to form cavities during thermal annealing at 1100℃.Microcracks and the extended defects prefer to nucleate in single crystalline α-SiC,but not polycrystalline α-Si C.Grain boundaries can account for the experimental results.The formation of cavities on grain boundaries is investigated.

Form and Interconversion Factor of Selenium in Soil

In recent years,production and processing of natural selenium-rich agricultural products has become a research hotspot. The main factor affecting the selenium content in plant is the content of effective selenium in soil. So it is important to understand the form and conversion relationship of selenium in soil and find ways to improve selenium effectiveness. By summarizing the researches on selenium at home and abroad,we analyze the classification of soil selenium form,the transformation among different selenium forms and the improving factors of selenium effectiveness. We understand the relationship between chemical form and extraction form of selenium,analyze the driving factors of conversion among different forms,and discuss the ways to improve selenium effectiveness of soil in high selenium-rich area. By combining characteristics of soil and crop in different selenium-rich regions,different selenium activation methods are used,which could provide more scientific evidence for further selenium research.

Isolation and Identification of Cellulose- decomposing Bacteria from Deep-litter Systems

In this study, 43 cellulose-decomposing strains were isolated from deep-litter systems. After preliminary screening with Congo red identification medium and filter paper strip medium, five strains with large transparent circles that disintegrated filter paper strips were obtained. After further liquid fermentation, CMC activity, FPA activity and natural eellulase activity of these five strains were determined, and two cellulose-decomposing strains with higher enzyme activity were screened, which were named F7 and F21. Based on molecular biological identification and phylogenetic analysis of 16S rRNA gene sequences, these two cellulose- decomposing strains were identified as Bacillus subtilis and Streptomyces sp. , respectively.