Template-assisted spray-drying method for the fabrication of porous particles with tunable structures

Developing strategies for the production of porous particles with controllable structures using a spray-drying method has attracted attention of researchers for decades. Although many papers have reported their successful production of porous particles using this method, information on how to create and control the porous structures as well as what parameters involving and what formation mechanism occurring during the synthesis process are still not clear. To meet these demands, the present review covers strategies in the spray-drying developments for the fabrication of porous particles with controllable structure. This information is important for optimizing the production of porous particles with desirable properties. Regulation of process conditions and precursor formulations are also explained, including composition, type, and physicochemical properties of droplet and raw components used (i.e., host component, template, and solvent). The electrostatic interactions between the individual components and the droplets are also presented, while this information tends to be neglected in the conventional spray-drying process. To clarify how the porous particles are designed, current experimental results completed with illustrations for the proposal particle formation mechanism are presented. The review also completed with the opportunities and potential roles of the changing porous structures in practical uses. This review would provide information on how to produce porous particles that can be used for advanced functional materials, such as catalysts, adsorbents, and sensors.     

Reformate-enriched gasoline-ethanol blends: Volatility criteria and azeotrope formation

Four hydrocarbon-base gasolines (BG) were formulated from the local refinery streams; isomerate, reformate, and light naphtha. The formulations were enriched in reformate. Each of these BG formulations was blended with 10 vol% of anhydrous ethanol. From ASTM-D86 distillation data, eight distillation curves were constructed and the trend line equations of these distillation curves were developed. Also, the area under each distillation curve (AUDC) was calculated through calculus definite integration technique. Subsequently, the area due to azeotrope formation (ADAF) for each BG-ethanol blend was estimated. In this paper, the influence of increasing reformate proportions on the created positive azeotrope, was studied. Also the influence of increasing reformate proportions on vapor pressure, Temperature for the vapor-liquid ratio of 20, T50 and octane number was studied. The results show that the R² values of the distillation curve equations prove the reliability of the fits. Also, increasing reformate proportion in the fuel blend improves the octane number while increasing reformate proportion decreases the volatility of the fuel formulation.     

Has China's coal consumption actually reached its peak? National and regional analysis considering cross-sectional dependence and heterogeneity

To investigate whether China's coal consumption has actually peaked, this study tests the national and regional coal Kuznets curve (CKC) hypothesis by using a panel dataset of 30 provinces covering 2000 to 2016. To fully capture the trends of coal consumption at the national, regional, and provincial levels, this study proposes a novel regional division method based on coal dependence and economic level. Considering the potential cross-sectional dependence and slope homogeneity, the newly developed methods allowing for heterogeneous slope coefficients are employed. The whole panel and subpanel results validate the CKC hypothesis for China, and province-specific results are mixed. The subpanel results reveal that only in the coal-dependent developing region has the peak of coal consumption not been reached, and for other regions, coal consumption displays a downward trend along with gross domestic product (GDP) increases. Furthermore, the province-specific results suggest that coal consumption will continue to increase slightly in certain provinces. This study implies that to reduce coal consumption, the coal-dependent developing region and provinces with a future turning point should act with great urgency to achieve a balance of economic growth and environmental responsibility. In addition, policymakers formulating coal consumption reduction policy in China must consider the remarkable differences across regions and provinces.     

分级加载电压下考虑有效电势变化的软黏土电渗固结理论

分级加载电压技术能够有效延长电渗处理的时间,改善地基的处理效果并能有效降低能耗。在利用分级加载电压技术开展电渗试验时,随着土体的排水固结,土体各点的电势会发生明显的变化,这与现有的电渗固结理论假设土体各点电势保持不变有所差异。利用自主设计的电渗试验仪器开展了分级加载电压下的电渗室内试验,分析了电渗过程中土体有效电势变化的规律。基于该规律并结合Esrig固结理论建立了在阳极处不排水、阴极处排水条件下考虑土体有效电势变化的电渗固结理论,得到了分级加载电压条件下考虑土体有效电势变化的超静孔隙水压力和平均固结度的解析表达式。研究表明,在电压分级加载过程中,土体有效电势变化规律表现为随时间先基本保持不变,后呈抛物线状先增后减。通过试验案例验证了考虑土体有效电势变化所求得解析解的合理性,且该数值计算结果相较于Esrig数值计算结果,前者更加接近实测值,该固结方程的建立为后续分级加载电压技术的推广应用提供了理论依据,也为实际工程提供了参考。     

2.5 GHz城市环境电磁态势的计算与补偿

复杂城市空间的电磁态势分布可以通过电磁场数值计算的方法进行预测。文章使用矩量法(MOM)结合一致性几何绕射理论(UTD)的方法对2.5 GHz频率下某小区环境中的电磁态势进行了仿真计算以及实际测量。场景中的树木结构在此频率下显示出比较强烈的波动性,对电磁仿真计算结果产生了不可忽略的影响,文中将其对仿真计算结果的影响进行了单独建模仿真,给出其产生影响的经验值,对仿真结果进行修正。修正结果与测量结果对比证明该经验值在该频率下可以有效补偿计算结果的缺失。     

Cell Death Mechanisms Induced by CLytA-DAAO Chimeric Enzyme in Human Tumor Cell Lines

The combination of the choline binding domain of the amidase N-acetylmuramoyl-L-alanine (CLytA)-D-amino acid oxidase (DAAO) (CLytA-DAAO) and D-Alanine induces cell death in several pancreatic and colorectal carcinoma and glioblastoma cell lines. In glioblastoma cell lines, CLytA-DAAO-induced cell death was inhibited by a pan-caspase inhibitor, suggesting a classical apoptotic cell death. Meanwhile, the cell death induced in pancreatic and colon carcinoma cell lines is some type of programmed necrosis. In this article, we studied the mechanisms that trigger CLytA-DAAO-induced cell death in pancreatic and colorectal carcinoma and glioblastoma cell lines and we acquire a further insight into the necrotic cell death induced in pancreatic and colorectal carcinoma cell lines. We have analyzed the intracellular calcium mobilization, mitochondrial membrane potential, PARP-1 participation and AIF translocation. Although the mitochondrial membrane depolarization plays a crucial role, our results suggest that CLytA-DAAO-induced cell death is context dependent. We have previously detected pancreatic and colorectal carcinoma cell lines (Hs766T and HT-29, respectively) that were resistant to CLytA-DAAO-induced cell death. In this study, we have examined the putative mechanism underlying the resistance in these cell lines, evaluating both detoxification mechanisms and the inflammatory and survival responses. Overall, our results provide a better understanding on the cell death mechanism induced by CLytA-DAAO, a promising therapy against cancer.     

羟基(—OH)对煤自燃侧链活性基团氧化反应特性的影响

针对煤结构及其氧化反应机理不明等问题,以羟基(—OH)和煤自燃侧链活性基团—OCH,—CHOHCH 3和—OCH 3为研究对象,采用密度泛函理论(DFT)的B3LYP-311G(d,p)方法,构建出了羟基(—OH)处于侧链活性结构邻位的小分子结构模型。基于前线轨道理论和量子化学理论,采用Gaussian 16软件对小分子模型的静电势、前线轨道的能级和电荷分布及煤氧复合反应过程中的热力学参数进行了模拟计算,探究了侧链活性基团的低温氧化特性和羟基(—OH)对其的影响。计算结果显示,在侧链活性结构中,氢原子周边呈强正电势,为亲核反应活性位点,而氧原子附近呈强负电势,为亲电反应活性位点。当羟基(—OH)处于侧链活性基团邻位时,会削弱侧链活性基团的亲电反应能力,增加—CHO和—CHOHCH 3的亲核反应能力,而使—OCH 3的亲核反应能力消失;通过分析各活性基团最高占据轨道(HOMO:Highest Occupied Molecular Orbital)和最低未占轨道(LUMO:Lowest Unoccupied Molecular Orbital)可知,侧链活性基团的稳定性与其前线轨道的成键能力并不一致,而活性基团与氧气发生复合反应的难易程度主要取决于该基团前线轨道中LUMO的成键能力,成键能力越强,复合反应越容易发生;由于羟基(—OH)改变了侧链活性基团前线轨道上的电子特性,故当其与侧链基团共存时,会使—CHO和—CHOHCH 3与氧气的复合反应更容易发生,而使—OCH 3与氧气的复合由自发的放热反应转变为非自发的吸热反应。该研究成果可为揭示煤自燃微观作用机理和研发煤自燃新型高效阻化材料提供参考。     

基于背压和最佳阀位控制的滑压曲线实时优化及应用

针对目前凝汽器背压对滑压值的修正无普适算式可供遵循的问题，通过作图法推理获得了滑压设定值与凝汽器背压及机组负荷之间的二元函数表达式；利用流量变工况计算方法解决最佳综合阀位的确定问题，在满足机组日常运行需求的条件下达到汽轮机高压调阀节流损失最小化；将提出的基于凝汽器背压和机组负荷的二元函数滑压实时优化和基于流量变工况计算的最佳综合阀位控制滑压实时优化方法相结合，将凝汽器背压对滑压值的修正作为粗调，将最佳综合阀位控制对滑压值的修正作为细调，共同实现对滑压设定值的实时调整。在某660 MW超临界机组上的应用表明，该方法能够节约供电煤耗约1.12 g/(kW·h）。     

Predictive association of metal–organic systems in the solid-state: the molecular electrostatic potential based approach

Designing crystalline solids with improved properties or performances remains a challenging task, despite great strides that have been made within the field of crystal engineering since its birth several decades ago. Herein, we are bringing examples that illustrate recent successes in taking supramolecular synthetic guidelines from the organic crystal engineering and adjusting those to metal-containing systems, particularly to the lower-dimensional ones. The versatility of calculated molecular electrostatic potential (MEP) as a new crystal engineering tool is demonstrated.     

Corrosion behaviour and mechanism of 6082 aluminium alloy in NaCl and Na2SO4 etchants

The corrosion behaviour of 6082 aluminium alloy was studied by measuring the electrochemical impedance spectra and electrode polarization curves. After the electrochemical tests, a microstructural analysis of the samples was conducted by using optical microscopy and electron scanning microscopy techniques to determine the corrosion mechanism. The results show that the Nyquist plot of the electrochemical impedance data in the NaCl solution consists of high- and low-frequency capacitive impedance loops. When ions are added to the NaCl etchant, the Nyquist plots of the electrochemical impedance data are composed of two different curves: a high-frequency capacitive impedance loop and a low-frequency inductive impedance loop. The corrosion current density increases with increasing concentration, and as a result, the corrosion resistance of the aluminium alloy decreases. The microstructures of 6082 aluminium alloy consist of Mg₂Si secondary particles in a large α-Al matrix. Pitting corrosion initially occurs at the boundary between the matrix and secondary particles because the electrode potentials of the matrix and secondary particles are different. Then, corrosion paths develop along the network-like grain boundaries, and finally, massive network-like corrosion occurs throughout the entire alloy.