Construction of 0D/2D Schottky Heterojunctions of ZnO and Ti3C2 Nanosheets with the Enriched Transfer of Interfacial Charges for Photocatalytic Hydrogen Evolution

The development of cost-effective co-catalysts of high photocatalytic activity and recyclability is still a challenge in the energy transformation domain. In this study, 0D/2D Schottky heterojunctions, consisting of 0D ZnO and 2D Ti₃C₂, were successfully synthesized by the electrostatic self-assembling of ZnO nanoparticles on Ti₃C₂ nanosheets. In constructing these heterojunctions, Ti₃C₂ nanosheets acted as a co-catalyst for enhancing the transfer of excitons and their separation to support the photocatalytic response of ZnO. The as-prepared ZnO/Ti₃C₂ composites demonstrate an abbreviated charge transit channel, a huge interfacial contact area and the interfacial electrons’ transport potential. The extended optical response and large reactive area of the ZnO/Ti₃C₂ composite promoted the formation of excitons and reactive sites on the photocatalyst’s surface. The ZnO/Ti₃C₂ Schottky heterojunction showed significantly high photocatalytic activity for hydrogen production from a water–ethanol solution under the light illumination in the visible region. The hydrogen evolution overoptimized the ZnO/Ti₃C₂ composition with 30 wt.% of Ti₃C₂, which was eight times higher than the pristine ZnO. These findings can be helpful in developing 0D/2D heterojunction systems for photocatalytic applications by utilizing Ti₃C₂ as a low-cost co-catalyst.     

全球甲型流感病毒H5A1序列的分子进化研究

目的应用生物信息学数据库和工具,对现有的H5亚型甲型流感病毒全球分离株的H5A1抗原序列进化规律进行研究。方法下载NCBI Genbank和美国洛斯阿莫斯国家实验室流感病毒数据库中全部的甲型流感病毒H5A1序列,采用快速极大似然法绘制进化树,并用SRDT模型估计各分枝的进化速度与出现时间。结果H5A1序列的进化树可被分为两个各自独立进化的世系:美洲世系和欧/亚世系,它们在地域分布、序列位点等方面区别明显,且可被进一步细分为几大进化枝,野生禽类分枝和家禽株系分枝的进化速度存在明显差异,所有的人及其他哺乳动物感染株系则均来自于欧/亚世系的亚洲禽/人分枝。结论H5A1序列在野生禽类中已达到相对稳定的状态,其自然变异速度为(1.990~2.535)×10-3/位点/年,而家禽中的高毒力变异株进化速度明显加快。目前威胁人类的主要是1996年之后出现的亚洲变异株,且进化树结构提示该株系出现过多次禽/人跨宿主传播事件,值得对其位点特征进行深入研究。     

桃仁现代研究进展和炮制方法历史沿革

桃仁Persicae Semen具有活血祛瘀、润肠通便、止咳平喘的功效,在我国具有广泛且悠久的应用历史。通过查阅历代本草典籍及现代研究文献报道,梳理桃仁的历史沿革,并对其现代炮制规范的研究进展进行归纳。为了全面理解药材,对桃仁的化学成分和药理作用的研究进展进行综述,还特别关注了药对配伍使用角度。有助于从多个方面全面了解药材的特性和潜在效果,为后续对桃仁炮制前后主要成分、指纹图谱、药理活性变化和减毒增效机制的研究提供研究思路,以期为其质量评价、临床应用和资源开发提供科学的理论依据。     

Thermodynamic Modeling Study of Carbonation of Portland Cement

The assessment of the extent of carbonation and related phase changes is important for the evaluation of the durability aspects of concrete. The phase assemblage of Portland cements with different clinker compositions is evaluated using thermodynamic calculations. Four different compositions of cements, as specified by ASTM cements types I to IV, are considered in this study. Calcite, zeolites, and gypsum were identified as carbonation products. CO₂ content required for full carbonation had a direct relationship with the initial volume of phases. The CO₂ required for portlandite determined the initiation of carbonation of C-S-H. A continual decrease in the pH of pore solution and a decrease in Ca/Si is observed with the carbonation of C-S-H. Type II cement exhibited rapid carbonation at relatively less CO₂for full carbonation, while type III required more CO₂ to carbonate to the same level as other types of cement. The modeling of carbonation of different Portland cements provided insights into the quantity of CO₂ required to destabilize different hydrated products into respective carbonated phases.     

Photocatalytic Hydrogen Evolution from Artificial Seawater Splitting over Amorphous Carbon Nitride: Optimization and Process Parameters Study via Response Surface Modeling

Photocatalytic water splitting has garnered tremendous attention for its capability to produce clean and renewable H₂ fuel from inexhaustible solar energy. Until now, most research has focused on scarce pure water as the source of H₂, which is not consistent with the concept of sustainable energy. Hence, the importance of photocatalytic splitting of abundant seawater in alleviating the issue of pure water shortages. However, seawater contains a wide variety of ionic components which have unknown effects on photocatalytic H₂ production. This work investigates photocatalytic seawater splitting conditions using environmentally friendly amorphous carbon nitride (ACN) as the photocatalyst. The individual effects of catalyst loading (X₁), sacrificial reagent concentration (X₂), salinity (X₃), and their interactive effects were studied via the Box–Behnken design in response surface modeling towards the H₂ evolution reaction (HER) from photocatalytic artificial seawater splitting. A second-order polynomial regression model is predicted from experimental data where the variance analysis of the regressions shows that the linear term (X₁, X₂), the two-way interaction term X₁X₂, and all the quadratic terms (X₁₂, X₂₂, X₂₃) pose significant effects towards the response of the HER rate. Numerical optimization suggests that the highest HER rate is 7.16 µmol/h, achievable by dosing 2.55 g/L of ACN in 45.06 g sea salt/L aqueous solution containing 17.46 vol% of triethanolamine. Based on the outcome of our findings, an apparent effect of salt ions on the adsorption behavior of the photocatalyst in seawater splitting with a sacrificial reagent has been postulated.     

从生物进化看脑苷脂类化合物的分布及其生物活性研究进展

脑苷脂类化合物是一类广泛存在于菌类、植物类、动物类及海洋生物组织细胞膜中含量很低的内源性生物活性物质。本文就近年来发现的脑苷脂类化合物的化学结构特点与生物进化相关性、脑苷脂类的生物合成与体内转化、生物活性与药理作用、应用前景等方面的研究进行综述和展望,为此类活性成分的深入研究提供参考。     

Numerical Analysis of Microcrack Propagation Characteristics and Influencing Factors of Serrated Structural Plane

The serrated structural plane is the basic unit of structural plane morphology. However, the understanding of its internal stress distribution, failure mode and crack evolution law was not clear enough in previous studies. In this paper, the shear mechanical properties of the serrated structural planes were studied by numerical simulation, and the crack evolution law of the serrated structural planes and the effects of four microscopic parameters on the shear properties were analyzed. The results show that: (1) the number of microcracks increases with the increase in normal stress; the crack expansion rate is slow before the shear stress reaches the peak. After the shear stress reaches the peak, the crack expansion rate continues to increase, and the microcracks keep sprouting and expanding, and the number of microcracks tends to stabilize when the shear stress reaches the residual shear strength. (2) The particle contact stiffness ratio kn∗/ks∗ and parallel bond stiffness ratio kn/ks were negatively correlated with the shear strength; and the particle contact modulus E and parallel bond modulus E∗ were positively correlated with the shear strength. As the particle contact modulus E and parallel bond modulus E∗ increase, the peak shear displacement gradually decreases. The parallel bond stiffness ratio kn/ks has a negative correlation with the peak shear displacement. This study is expected to provide theoretical guidance for the microscopic parameter calibration and shear mechanical analysis of serrated structural planes. (3) Several XGBoost, WOA-XGBoost, and PSO-XGBoost algorithms are introduced to construct the quantitative prediction model, and the comparative analysis found that WOA-XGBoost has the best fitting effect and can be used for the prediction of shear strength. When using this model to calculate the weight shares of micro-parameters, it was found that kn∗/ks∗ has the greatest influence on shear strength, followed by E∗; E and kn/ks had the least influence.     

Influence of Structural Porosity and Martensite Evolution on Mechanical Characteristics of Nitinol via In-Silico Finite Element Approach

Nitinol (NiTi) alloys are gaining extensive attention due to their excellent mechanical, superelasticity, and biocompatibility properties. It is difficult to model the complex mechanical behavior of NiTi alloys due to the solid-state diffusionless phase transformations, and the differing elasticity and plasticity presenting from these two phases. In this work, an Auricchio finite element (FE) model was used to model the mechanical behavior of superelastic NiTi and was validated with experimental data from literature. A Representative Volume Element (RVE) was used to simulate the NiTi microstructure, and a microscale study was performed to understand how the evolution of martensite phase from austenite affects the response of the material upon loading. Laser Powder Bed Fusion (L-PBF) is an effective way to build complex NiTi components. Porosity being one of the major defects in Laser Powder Bed Fusion (L-PBF) processes, the model was used to correlate the macroscale effect of porosity (1.4–83.4%) with structural stiffness, dissipated energy during phase transformations, and damping properties. The results collectively summarize the effectiveness of the Auricchio model and show that this model can aid engineers to plan NiTi processing and operational parameters, for example for heat pump, medical implant, actuator, and shock absorption applications.     

Xenohormesis:从进化与生态角度理解中药的生物效应

Xenohormesis解释了为何植物受环境胁迫后产生的次生代谢产物能提高取食动物的胁迫耐受性与生存机会,认为在自然选择压力下动物保留着感知这些胁迫信号分子的能力,从而激活进化保守性的细胞应激响应机制,提高逆境适应力.该文在介绍Xenohormesis效应概念与机制,分析总结植物与昆虫及人类的Xenohormesis效应关系的基础上,以人参为例阐述了中药Xenohormesis效应,认为借鉴Xenohormesis理论能从进化与生态角度理解中药生物效应的本质,对中药现代化研究具重要价值.     

中药白芷的基原植物研究Ⅳ.白芷的基原植物、栽培历史以及其近缘野生植物演化的讨论

目的 :确认中药白芷的基原植物 ,探讨其栽培历史变化以及有关近缘野生植物的演化。方法 :对已取得的各项研究结果作综合分析 ,并结合历史文献、分布现状等进行讨论。结果 :各项研究结果与历史文献、分布现状等均较为一致。结论 :①中药白芷的基原植物应是台湾白芷。②建议将雾灵当归处理为兴安白芷的变种 ,定名为A .dahuricavar.porphyrocaulis。③对川 (杭 )白芷和祁 (禹 )白芷不应作分类学上的区分。同时 ,还对中药白芷的使用栽培历史和白芷的野生近缘植物兴安白芷、台湾白芷和雾灵当归的演化关系作出了推断。