Fe、Ce、Cu对Mn/AC催化剂低温脱硝及抗硫性能的影响研究

通过浸渍法制备了Fe、Ce、Cu和Mn含量比不同的系列金属-Mn/AC催化剂,利用XRD、BET、SEM等进行了表征,对其NH_3-SCR低温脱硝性能和抗硫性能进行了研究。结果表明,金属改性对Mn/AC催化剂的低温脱硝性能和抗硫性能均有较大提升,改性后的催化剂比表面积增加,孔径、孔容降低,其中Fe(15)Mn(10)/AC催化剂表现最好,铁和锰均能以无定形氧化物良好分散于载体表面,该催化剂具备丰富的酸性位,良好的氧化还原性能,在120～200℃下脱硝效率均可达90%,在通入SO_2条件下,仍有70%的脱硝效率,并且经济性适中,便于推广。     

Mass Spectrometric Assays Reveal Discrepancies in Inhibition Profiles for the SARS-CoV-2 Papain-Like Protease

The two SARS-CoV-2 proteases, i. e. the main protease (M^pro) and the papain-like protease (PL^pro), which hydrolyze the viral polypeptide chain giving functional non-structural proteins, are essential for viral replication and are medicinal chemistry targets. We report a high-throughput mass spectrometry (MS)-based assay which directly monitors PL^pro catalysis in vitro. The assay was applied to investigate the effect of reported small-molecule PL^pro inhibitors and selected M^pro inhibitors on PL^pro catalysis. The results reveal that some, but not all, PL^pro inhibitor potencies differ substantially from those obtained using fluorescence-based assays. Some substrate-competing M^pro inhibitors, notably PF-07321332 (nirmatrelvir) which is in clinical development, do not inhibit PL^pro. Less selective M^pro inhibitors, e. g. auranofin, inhibit PL^pro, highlighting the potential for dual PL^pro/M^pro inhibition. MS-based PL^pro assays, which are orthogonal to widely employed fluorescence-based assays, are of utility in validating inhibitor potencies, especially for inhibitors operating by non-covalent mechanisms.     

Biodegradable,superhydrophobic walnut wood membrane for the separation of oil/water mixtures

The preparation of environmentally friendly oil/water separation materials remains a great challenge. Freeze-drying of wood after lignin removal yields wood aerogels, which can be used as substrates to prepare fluorine-free environmentally friendly superhydrophobic materials, However, they are more suitable for absorption rather than filtration applications due to their poor strength. A study using cross-sections of pristine wood chips as substrates retains the original strength of wood, but the use of the cross-sectional of wood pieces limits their thickness, strength, and size. In this paper, a degradable fluorine-free superhydrophobic film (max. water contact angle of approximately 164.2°) with self-cleaning and abrasion resistance characteristics was prepared by a one-step method using pristine and activated walnut longitudinal section films as the substrate, with tetraethyl orthosilicate as a precursor and dodecyltriethoxysilane as a modifier. The tensile strength results show that superhydrophobic films with pristine or activated wood substrates maintained the strength of pristine wood and were 2.2 times stronger than the wood aerogel substrate. In addition, after cross-laminating the two samples, the films had the ability to separate oil and water by continuous filtration with high efficiency (98.5%) and flux (approximately 1.3 × 10³ L∙m^‒2∙h^‒1). The method has potential for the large-scale fabrication of degradable superhydrophobic filtration separation membranes.     

Carbon-coated Ni-Co alloy catalysts: preparation and performance for in-situ aqueous phase hydrodeoxygenation of methyl palmitate to hydrocarbons using methanol as the hydrogen donor

Carbon-coated Ni, Co and Ni-Co alloy catalysts were prepared by the carbonization of the metal doped resorcinol-formaldehyde resins synthesized by the one-pot extended Stöber method. It was found that the introduction of Co remarkably reduced the carbon microsphere size. The metallic Ni, Co, and Ni-Co alloy particles (mainly 10–12 nm) were uniformly distributed in carbon microspheres. A charge transfer from Ni to Co appeared in the Ni-Co alloy. Compared with those of metallic Ni and Co, the d-band center of the Ni-Co alloy shifted away from and toward the Fermi level, respectively. In the in-situ aqueous phase hydrodeoxygenation of methyl palmitate with methanol as the hydrogen donor at 330 °C, the decarbonylation/decarboxylation pathway dominated on all catalysts. The Ni-Co@C catalysts gave higher activity than the Ni@C and Co@C catalysts, and the yields of n-pentadecane and n-C₆–n-C₁₆ reached 71.6% and 92.6%, respectively. The excellent performance of Ni-Co@C is attributed to the electronic interactions between Ni and Co and the small carbon microspheres. Due to the confinement effect of carbon, the metal particles showed high resistance to sintering under harsh hydrothermal conditions. Catalyst deactivation is due to the carbonaceous deposition, and the regeneration with CO₂ recovered the catalyst reactivity.     

上海环球金融中心结构设计简析

上海环球金融中心是一座多功能、先进智能型的摩天大厦，建成后总高度达492米，为世界第一高楼。设计建造这一超级摩天大厦是一项复杂的系统工程，尤其在结构设计方面，如何选用最有效的结构体系，如何建立完善的计算模型，以及如何进行全面的计算分析都是结构设计的关键问题。本对上海环球金融中心的结构设计及施工方案进行了较全面的介绍。     

水泥石热膨胀性能的研究

对水泥石从室温(20℃)升到600℃和经室温到180℃热循环后再从室温升至600℃的热膨胀率进行了研究,结果表明,2种条件下水泥石热膨胀率的变化均表现为随温度的升高先提高而后再降低的趋势,而热膨胀率达最大值时前者温度较后者低70℃左右,即热循环可以提高水泥石在受热时出现收缩的温度值.借助于DSC/TG和XRD测试手段,对水泥石的热膨胀性能变化规律进行了机理分析.     

基于ANSYS分析比较有无腹筋对梁抗爆的影响

初步介绍了ANSYS/LS-DYNA软件在爆炸研究中的应用,然后用这个软件模拟了炸药爆炸荷载对悬臂梁产生的影响,并分析箍筋在构件抗爆过程中所起到的作用。     

地震区建筑用钢的韧性对建筑物抗震性能的影响

根据地震区建筑用钢在交变地震载荷下的服役条件及其失效模式的特点 ,分析了钢的韧性对建筑物抗震性能的影响。介绍了国外有关动态及国内现状 ,提出了地震区建筑用钢避免低温低应力脆断的建议     

Efficiency of activated carbon to transform ozone into *OH radicals: influence of operational parameters

Based on previous findings (Jans, U., Hoigné, J., 1998. Ozone Sci. Eng. 20, 67-87), the activity of activated carbon for the transformation of ozone into *OH radicals including the influence of operational parameters (carbon dose, ozone dose, carbon-type and carbon treatment time) was quantified. The ozone decomposition constant (k(D)) was increased by the presence of activated carbon in the system and depending on the type of activated carbon added, the ratio of the concentrations of *OH radicals and ozone, the R(ct) value ([*OH]/[O3]), was increased by a factor 3-5. The results obtained show that the surface chemical and textural characteristics of the activated carbon determines its activity for the transformation of ozone into *OH radicals. The most efficient carbons in this process are those with high basicity and large surface area. The obtained results show that the interaction between ozone and pyrrol groups present on the surface of activated carbon increase the concentration of O2*- radicals in the system, enhancing ozone transformation into *OH radicals. The activity of activated carbon decreases for extended ozone exposures. This may indicate that activated carbon does not really act as a catalyst but rather as a conventional initiator or promoter for the ozone transformation into *OH radicals. Ozonation of Lake Zurich water ([O3] = 1 mg/L) in presence of activated carbon (0.5 g/L) lead to an increase in the k(D) and R(ct) value by a factor of 10 and 39, respectively, thereby favouring the removal of ozone-resistant contaminants. Moreover, the presence of activated carbon during ozonation of Lake Zurich water led to a 40% reduction in the content of dissolved organic carbon during the first 60 min of treatment. The adsorption of low concentrations of dissolved organic matter (DOM) on activated carbon surfaces did not modify its capacity to initiate/promote ozone transformation into *OH radicals.