Intrinsic Mechanisms of Morphological Engineering and Carbon Doping for Improved Photocatalysis of 2D/2D Carbon Nitride Van Der Waals Heterojunction

Van der Waals(VDW)heterojunctions in a 2D/2D contact provide the highest area for the separation and transfer of charge carriers.In this work,a top-down strategy with a gas erosion process was employed to fabricate a 2D/2D carbon nitride VDW heterojunction in carbon nitride(g-C_(3)N_(4))with carbon-rich carbon nitride.The created 2D semiconducting channel in the VDW structure exhibits enhanced electric field exposure and radiation absorption,which facilitates the separation of the charge carriers and their mobility.Consequently,compared with bulk g-C_(3)N_(4)and its nanosheets,the photocatalytic performance of the fabricated carbon nitride VDW heterojunction in the water splitting reaction to hydrogen is improved by 8.6 and 3.3 times,respectively,while maintaining satisfactory photo-stability.Mechanistically,the finite element method(FEM)was employed to evaluate and clarify the contributions of the formation of VDW heterojunction to enhanced photocatalysis,in agreement quantitatively with experimental ones.This study provides a new and effective strategy for the modification and more insights to performance improvement on polymeric semiconductors in photocatalysis and energy conversion.

The Nature of Active Sites for Plasmon-Mediated Photothermal Catalysis and Heat-Coupled Photocatalysis in Dry Reforming of Methane

Solar energy-induced catalysis has been attracting intensive interests and its quantum efficiencies in plasmon-mediated photothermal catalysis(P-photothermal catalysis)and external heat-coupled photocatalysis(E-photothermal catalysis)are ultimately determined by the catalyst structure for photo-induced energetic hot carriers.Herein,different catalysts of supported(TiO_(2)-P25 and Al_(2)O_(3))platinum quantum dots are employed in photo,thermal,and photothermal catalytic dry reforming of methane.Integrated experimental and computational results unveil different active sites(hot zones)on the two catalysts for photo,thermal,and photothermal catalysis.The hot zones of P-photothermal catalysis are identified to be the metal-support interface on Pt/P25 and the Pt surface on Pt/Al_(2)O_(3),respectively.However,a change of the active site to the Pt surface on Pt/P25 is for the first time observed in E-photothermal catalysis(external heating temperature of 700℃).The hot zones contribute to the significant enhancements in photothermal catalytic reactivity against thermocatalysis.This study helps to understand the reaction mechanism of photothermal catalysis to exploit efficient catalysts for solar energy utilization and fossil fuels upgrading.

La-doped TiO_(2) nanorods toward boosted electrocatalytic N_(2)-to-NH_(3)conversion at ambient conditions

Electrochemical N_(2) reduction provides a green and sustainable alternative to the Haber-Bosch technology for NH_(3 )synthesis.However,the extreme inertness of N_(2) molecules is a formidable challenge,which requires the development of an active electrocatalyst to drive the N_(2) reduction reaction(NRR)for NH_(3) production at ambient conditions.Herein,we demonstrate the development of La-doped TiO_(2) nanorods as an efficient NRR electrocatalyst for ambient NH3 synthesis.The optimized La-TiO_(2) catalyst offers a large NH_(3) yield of 23.06 pg h1 mgcat 1 and a high Faradaic efficiency of 14.54%at-0.70 V versus reversible hydrogen electrode in 0.1 M L1CIO_(4),outperforming most La-and Ti-based catalysts reported before.Significantly,it also demonstrates high electrochemical stability and its activity decay is negligible after 48 h test.The mechanism is further revealed by density functional theory calculations.

Comparative Analysis of Proanthocyanidins and Polysaccharides on Wild Lycium ruthenicum

[Objectives] To compare content of proanthocyanidins and polysaccharides in wild Lycium ruthenicum. [Methods] The wild L. ruthenicum collected from different regions such as Qinghai, Inner Mongolia, Ningxia and Gansu Province were taken as the research objects. The conventional indicators such as proanthocyanidins and polysaccharides of the experimental materials were determined, and the proanthocyanidins and polysaccharides of the experimental materials in different regions were compared and analyzed. The difference in content and correlation, and the cluster analysis method were used to divide clusters of the experimental materials. [Results] The absorbance of proanthocyanidins in the fruit of wild L. ruthenicum was No.4>No.1>No.5>No.6>No.3>No.2, among which the absorbance of anthocyanin(2.43) of wild L. ruthenicum variety No.4 was significantly higher than other experimental materials(P<0.05), and proanthocyanidin of No.2 had the lowest absorbance value of 1.35. There was no significant difference between No.3 and No.6(P>0.05), and there were significant differences among other experimental materials(P<0.05). The content of polysaccharides was: No.3>No.7>No.2>No.4>No.5>No.6>No.1; there was no significant difference between No.3 and No.7(P>0.05), but significantly higher than other materials(P<0.05). Besides, proanthocyanidins and polysaccharides showed significant variability, but there was no consistency in the correlation between them. [Conclusions] In terms of the absorbance of proanthocyanidins, the experimental materials No.1 and No.4 can be classified into a cluster; experimental materials No.2, No.3, No.5 and No.6 can be classified into another cluster. This can provide a theoretical basis for the introduction and breeding of fine varieties.

Simulated biomass tar removal mechanism by a Quench Coupled with ADsorption Technology(QCADT)

Tar removal is a bottleneck in the smooth commercialization of biomass gasification technology. Based on introducing adsorption process into Quench Coupled with ABsorption Technology(QCABT) previously proposed by the author’s group, Quench Coupled with ADsorption Technology(QCADT) has been developed to narrow this gap. Additionally, benzene and naphthalene, which are more similar to the real tar for containing aromatic ring structures, were adopted as light and heavy simulated tar, respectively. Also their removal behavior by QCADT was investigated. The results show that the removal mechanism of QCADT is similar to that of QCABT, except for the higher overall tar removal rate due to adsorption effect. Adsorbents with both micro-and narrow mesopores exhibit a better benzene removal performance, while narrow mesopores play dominant roles in naphthalene removal. Penetration adsorption loading of benzene and naphthalene on AC-1 can reach0.38 g·g^-1 and 0.34 g·g^-1, respectively. The sawdust hardly has any tar removal effect. Combined micro-and meso-pores, will benefit both deep tar removal and large adsorption rate, providing a high tar removal efficiency.

Sm^(2+)ions boost ammonia electrooxidation reaction on samarium oxide anode for hydrogen generation in non-aqueous electrolyte

Ammonia has garnered recognition as a zero-carbon fuel due to its high-density hydrogen storage capacity and its convenience for storage and transportation.To address the challenges associated with the direct usage of ammonia,the development of NH_(3)-to-H_(2)conversion technologies has emerged as a promising and effective approach.Herein,we present for the first time that crystallized Sm_(2)O_(3−x)electrodes demonstrate high and stable electrocatalytic activities,including N_(2)evolution rate and Faradaic efficiency,for ammonia electrolysis in a non-aqueous electrolyte.It was observed that Sm^(2+)ions in samarium oxide play an indispensable role in the ammonia electrooxidation reaction on the anodes.Furthermore,the mechanism of ammonia electrooxidation has also been elucidated,laying the foundation for a better understanding of the relationship between local structure and electrochemical properties in order to facilitate research on Pt-free electrocatalysts for the electrolysis of ammonia into H_(2).

基于随机森林模型内脏脂肪等级相关指标分析

目的探讨基于随机森林模型分析内脏脂肪等级的相关指标。方法本研究为横断面研究,选取2021年3—9月在黑龙江省医院健康管理中心进行体检的医院职工(包括在职职工和退休职工)共617例的各项实验室指标以及体成分分析各项指标,按照2∶1的比例将样本分为训练集(411例)和测试集(206例),模型共纳入预测变量110个,使用训练集数据进行随机森林模型构建,测试集数据进行模型验证,选择最优节点数和决策树数目,对构建模型的预测性能进行评价,同时选取重要性在前10位的相对重要因子进行下一步的研究。按内脏脂肪等级,对617名研究对象再次进行分组:内脏脂肪等级正常组和内脏脂肪等级偏高组,进一步分析前10位相对重要因子在组间的差异。结果随机森林模型的最优节点数为39、决策树数目为300。模型在测试集上的准确率为83.3%、精确率为73.9%、灵敏度为89.4%、特异度为78.7%,其受试者工作特征曲线下面积为0.881(95%CI:0.832~0.931)。模型中前10位相对重要因子依次为:体重指数、性别、年龄、尿酸、红细胞计数、单核细胞计数、C肽、癌胚抗原、糖化血红蛋白、谷氨酰转肽酶。内脏脂肪等级偏高组的体重指数、年龄、尿酸、红细胞计数、单核细胞计数、C肽、癌胚抗原、糖化血红蛋白、谷氨酰转肽酶水平均高于内脏脂肪等级正常组(均P<0.05);内脏脂肪等级偏高的发生率男性大于女性(P<0.05)。结论本研究构建的内脏脂肪等级的随机森林预测模型表现良好,内脏脂肪与机体肝功能、胰岛功能、免疫功能的改变均有关系。

磷酸化石墨烯吸附铀的性能研究

本文利用简单的原位磷酸化反应,成功地将磷酸基团接枝到氧化石墨烯的表面,制备了一种磷酸化石墨烯吸附材料(PGO).采用扫描电子显微镜(SEM)和透射电子显微镜(TEM)表征了PGO的微观形貌,通过傅里叶转换红外光谱(FT-IR)、X射线光电子能谱(XPS)和拉曼光谱(Raman)等表征了PGO表面官能团的结构.结果表明,磷酸基团通过与GO中的C–O–C反应引入.系统研究了pH、离子强度、温度和时间等对PGO吸附铀性能的影响. pH是影响吸附铀过程的主要因素,吸附过程受离子强度影响较弱,说明PGO的吸附受内层表面络合控制;吸附过程符合Langmuir模型,单分子饱和吸附容量为396.83 mgg^(-1),高于GO (249.38 mgg^(-1));吸附过程符合准二级动力学模型,证明化学吸附占有主导地位;热力学参数(ΔG、ΔH、ΔS)表明吸附过程是吸热和自发的; PGO吸附铀的选择率高达56%,用1.0 molL^(-1)HCl洗脱时,脱附率达到98%; 5次吸附、脱附循环后PGO的吸附量仅降低了13%.磷酸化石墨烯在放射性废水处理领域具有广阔的应用前景.

油气工况下提升管出口旋流快分系统性能的数值研究

为促进旋流快分(SVQS)系统的工业应用、准确评估其性能,参照国家标准设计了一系列不同密度、黏度的油气模型,并采用商用软件FLUENT 2019 R3对一套Φ600 mm×3150 mm的SVQS系统进行了流动模拟和可行性验证。用单因素变量法分别研究了油气性质对系统无量纲切向速度和压降的影响;用标量输运方程分析了油气在系统内的停留时间分布规律。结果表明,无量纲切向速度随油气密度增加或黏度降低而变大;无量纲最大切向速度随油气密度增加或黏度减小而呈对数递增,最大为0.912;密度越大、黏度越小的油气在SVQS系统内的平均停留时间越短,最短可达6.279 s;压降、阻力系数不仅与系统的结构参数相关,也与油气黏度呈对数关系。拟合得到了与油气参数相关的无量纲切向速度、压降和阻力系数函数式,具有较好的普适性,可为SVQS系统的结构优化提供参考。

不同油气参数下SVQS系统内颗粒浓度场的模拟

为研究提升管出口旋流快分(SVQS)系统中催化剂颗粒的运动规律与浓度分布特征,对不同油气参数下SVQS系统的气固分离进行了数值流动模拟,从粒径、浓度分布和颗粒返混三个方面进行了分析。结果表明,在入口浓度一定的情况下,油气密度越大或黏度越小,封闭罩壁面处颗粒浓度越大,呈螺旋状分布的细带带宽和螺距不同;在隔流筒盖板处有颗粒大量聚集,并形成具有周期脱落特点的颗粒环带;隔流筒底部出现的“短路流”现象,削弱了SVQS系统的分离性能;不同粒径的颗粒下行时始终处于螺旋分层排列状态,且SVQS系统对直径为0.013 mm以下的细小颗粒的分离性能较弱。油气密度越大或黏度越小,颗粒间的跟随性更佳,浓度分布更均匀,SVQS系统对中、细颗粒的捕捉能力变强。SVQS系统中存在颗粒返混现象,且随油气密度增大或黏度减小而削弱。削弱颗粒返混、抑制颗粒高峰是提高该系统分离性能的重要方式。

Recent progress in sono-photodynamic cancer therapy:From developed new sensitizers to nanotechnology-based efficacy-enhancing strategies

Many sensitizers have not only photodynamic effects,but also sonodynamic effects.Therefore,the combination of sonodynamic therapy(SDT)and photodynamic therapy(PDT)using sensitizers for sonophotodynamic therapy(SPDT)provides alternative opportunities for clinical cancer therapy.Although significant advances have been made in synthesizing new sensitizers for SPDT,few of them are successfully applied in clinical settings.The anti-tumor effects of the sensitizers are restricted by the lack of tumor-targeting specificity,incapability in deep intratumoral delivery,and the deteriorating tumor microenvironment.The application of nanotechnology-based drug delivery systems(NDDSs)can solve the above shortcomings,thereby improving the SPDT efficacy.This review summarizes various sensitizers as sono/photosensitizers that can be further used in SPDT,and describes different strategies for enhancing tumor treatment by NDDSs,such as overcoming biological barriers,improving tumor-targeted delivery and intratumoral delivery,providing stimuli-responsive controlled-release characteristics,stimulating anti-tumor immunity,increasing oxygen supply,employing different therapeutic modalities,and combining diagnosis and treatment.The challenges and prospects for further development of intelligent sensitizers and translational NDDSs for SPDT are also discussed.

Cooperation between Pt and Ru on RuPt/AC bimetallic catalyst in the hydrogenation of phthalates

RuPt/AC bimetallic catalysts were pre pared by two-step incipient impregnation method and evaluated in the hydrogenation of phthalates.According to the characterization results,well dispersed Ru Pt bimetallic nanoparticles were formed on the catalyst,and the strong interaction between the two metals resulted in the formation of RuPt alloy.It was found that Ru can donate electrons to Pt on RuPt alloy nanoparticles,leading to the formation of electron-deficient Ru which significantly promotes the hydrogenation rate of dioctyl phthalate and improves the selectivity of dioctyl di-2-ethylhexylcyclohexane-1,4-dicarboxylate by accelerating the further hydrogenation of intermediate products.The bimetallic RuPt catalyst also presented excellent stability and versatility in the hydrogenation of phthalates,demonstrating its prospective future in the hydrogenation of aromatic ring contained compounds.

Systematic Synthesis of Dedicated Hybrid Transmission

The great diversity of dedicated hybrid transmissions(DHTs)requires a method to identify solutions among all potential concepts involved in each structure.Therefore,a DHT synthesis tool is developed on the basis of general transmission synthesis.In the first synthesis step,transmission structures are generated with only conventional functions such as driving with only the internal combustion engine.Electric machines are then installed in the transmissions to achieve further hybrid functions,including boosting,eCVT and electric driving modes.The number of generated transmission concepts increases exponentially with each synthesis step.Various evaluations are carried out successively to identify the most suitable DHT concepts among the many possible solutions.The generated DHT concepts are evaluated in terms of structural feasibility,driving modes,drivability and load factors on transmission components.An example of DHT synthesis involving planetary gear sets is explained in detail.The best five DHT structures are identified out of more than 120 billion solutions.

Study of Series-Parallel and Power-Split DHT for Hybrid Powertrains

Dedicated hybrid transmission(DHT)is the developing trend of hybrid transmissions.This paper studies different types of DHTs regarding the structure,function,and performance.Firstly,the structure and function of different well-known DHTs in the market are discussed and analyzed.Through the analysis,the reasonability and necessity of the different modes and the electric motor power requirements that lie behind different DHTs are derived.Secondly,the dynamics of different DHTs are further compared with the driving areas in different modes under different driving conditions.Then,the basic or minimum dynamic requirements are defined and taken into consideration before the economic comparison.To ensure the effectiveness of the comparison,the optimization of the configurations for each kind of DHT is carried out with the modular simulation model.The economic comparison is conducted under the premise of excluding the influences of the configurations in the results.Finally,the sensitivity and influence of different engine characteristics for different DHTs are studied to find out the sensibilities of the two kinds of DHTs with engine technology.Through these studies,the essential differences and features of different DHTs can be derived to help better understand the decision in choosing the technical route for the original equipment manufacturers.

Efficient silver nanocluster photocatalyst for simultaneous methyl orange/4-chlorophenol oxidation and Cr(Ⅵ) reduction

Metal nanoclusters have shown great potential in photocatalysis,while simultaneous removal of both inorganic and organic contaminants by metal nanoclusters under visible light is less explored.Here,we synthesized Agm(SR)n(SR represents 3-mercaptopropyltriethoxysilane ligand) nanoclusters(~1 nm) via a reduction of silver triphenylphosphine under ambient conditions in the presence of 3-mercaptopropyltriethoxysilane.The nanocluster was characterized by UV-vis spectroscopy,high resolution transmission electron microscopy(HRTEM),Fourier transform infrared spectrum(FTIR),and X-ray photoelectron spectroscopy(XPS).Under 5 W blue LED,the Agm(SR)n/P25 exhibits enhanced catalytic activity for simultaneous methyl orange(MO) oxidation and Cr(Ⅵ) reduction,and also for synchronous 4-chlorophenol oxidation and Cr(Ⅵ) reduction.Mechanism studies by electrochemical impedance spectroscopy(EIS),photoluminescence(PL),electron spin resonance(ESR) etc.and control experiments reveal that the unique structure of silver nanoclusters with thiolate ligands is vital to the high catalytic performance,and both the photo-generated holes and superoxide radicals are responsible for the decomposition of MO.

UNCERTAINTY ANALYSIS OF ROCK FAILURE BEHAVIOUR USING AN INTEGRATION OF THE PROBABILISTIC COLLOCATION METHOD AND ELASTO-PLASTIC CELLULAR AUTOMATON

The Karhunen-Loeve （KL） expansion and probabilistic collocation method （PCM） are combined and applied to an uncertainty analysis of rock failure behavior by integrating a self- developed numerical method （i.e., the elastic-plastic cellular automaton （EPCA））. The results from the method developed are compared using the Monte Carlo Simulation （MCS） method. It is concluded that the method developed requires fewer collocations than MCS method to obtain very high accuracy and greatly reduces the computational cost. Based on the method, the elasto- plastic and elasto-brittle-plastic analyses of rocks under mechanical loadings are conducted to study the uncertainty in heterogeneous rock failure behaviour.

Engineering BiOBr_(x)I_(1-x)solid solutions with enhanced singlet oxygen production for photocatalytic benzylic C-H bond activation mediated by N-hydroxyl compounds

The aerobic,selective oxidation of hydrocarbons via C-H bond activation is still a challenge.This work shows the achievement of the room temperature visible light driven photocatalytic activation of benzylic C-H bonds with N-hydroxysuccinimide over BiOBr_(x)I_(1-x)(0≤x≤1)solid solutions,whose valance bands were engineered through varying the ratio of bromide to iodide.The optimal BiOBr0.85I0.15 catalyst exhibited over 98%conversion ratio of ethylbenzene,which was about 3.9 and 8.9 times that of pure BiOBr and BiOI,respectively.The excellent photocatalytic activity of BiOBr0.85I0.15 solid solution can be ascribed to the orbital hybridization of the valence band containing both Br 4p and I 5p orbitals,which could promote photo-induced charge carrier separation and improve the generation of singlet oxygen.This work shed some light on the rational design of photocatalysts for targeted organic transformation.