Sea Power and China's Strategic Choices

China's national goals have shifted from the need to guarantee its survival during the country's revolutionary days to the current state of securing stable economic development. This shift marks a full transition for China, changing from a closed country to a developing one that is irrevocably integrated with the rest of the world. Today, while this subject is a common discourse in scholarly and political circles, the international community is still coming to grips with the meaning and impact of China's evolving role on the world stage. It is not an easy issue and extends beyond economics

Occurrence and genetic mechanism of pyrite in the No. 9 coal seam in magmatic erosion area of the Handan coalfield

The No. 9 coal of Yunjialing Coal Mine in Handan Coalfield, which is subject to obvious magmatic intrusion, is taken as the research object. Optical microscope observation, electron probe energy spectrometry (EPMA-EDS), X-ray diffractometer (XRD), X-ray fluorescence spectrometry (XRF) and other analytical tests were used to analyze the enrichment characteristics of whole sulfur, sulfur forms and minerals, to study the occurrence of sulfur and pyrite in the coals, and to explore the sources of different types of pyrite. The results show that the No. 9 coal of Yunjialing Coal Mine in Handan Coalfield is a high-sulfur coal (0.61%～7.12%), sulfide sulfur is the main form of sulfur in the coal (1.18%～4.90%), followed by organic sulfur (0.56%～2.16%) with a little sulphate sulfur (0.01%～0.06%). The No. 9 coal of Yunhailing coal mine was deposited in the transitional environment of sea and land phases, and seawater intrusion provided abundant sulfur source for the No. 9 coal seam, the gas-liquid materials brought about by neutral magmatism during the Yanshan period elevate the total sulfur content in the No. 9 coal of the Yunjialing Caol Mine, especially the total sulfur content of the upper coal plies are significantly higher than the total sulfur content of the whole coal seam. The microscopic occurrence of pyrite in the No. 9 coal mainly includes massive pyrite, disseminated pyrite and fissure-filled pyrite, and is characterized by multi-stage evolution. Massive pyrite is mainly formed in the early diagenetic stage, the high temperature and gas-liquid materials brought about by neutral magmatism during the Yanshan period modified the morphology of pyrite in the coal, resulting in the activation and recrystallization of pyrite in the coal into a massive fraction. Inorganic sulfur from the high-temperature-affected portion of the pyrite diffused into the surrounding coal body and sequestered as organic sulfur, increasing the organic sulfur content of the upper coal plies

Geochemical characteristics of rare earth elements in Late Permian coals in Western Henan and indicative meaning

With the wide application of rare earth metals in high-tech fields such as medical treatment and new materials, its strategic position has been increasing. As a major country in rare earth, China supplies rare earth products of different varieties and grades to all countries in the world, making great contributions to the development of emerging industries in the world .In order to explore the enrichment degree, occurrence state and sedimentary environment of rare earth elements in late Permian coal in western Henan, 20 stratified coal samples from No.21 coal in Huixiang mining area in western Henan were taken as the main research object. The rare earth elements and major elements in stratified coal samples were measured by ICP-MS and XRF, and the content characteristics and enrichment degree of rare earth elements in coal samples were discussed. The occurrence state and sedimentary environment of rare earth elements in samples were discussed by correlation analysis and characteristic parameters .The results show that the mass concentration of REY is 35.29-133.61 μg/g, and the average concentration is 79.14 μg/g, which is slightly higher than the average concentration of REY in the world coal, but obviously lower than the average concentration of REY in China coal. The REY content is low, and LREY is mainly enriched. There is a significant positive correlation between REY and ash content (Ad), SiO2, Al2O3 and other major oxides in the No.21 coal of Huixiang mining area, indicating that REY mainly occurs in clay minerals .The negative anomalies of Ce and Eu elements and slight positive anomalies of (Gd/Gd)N* in the samples in the study area indicate that the study area is mainly affected by terrigenous sources and the coal forming environment is a weakly acidic reducing environment

Mineralogical Characteristics of Early Permian Paragonite-Bearing Coal (No. 3) in the Jinyuan Mine, Tengxian Coalfield, Shandong Province, Eastern China

The Early Permian coal is of great value in the Tengxian Coalfield, Shandon Province, Eastern China. This work deals with the new data focusing on mineralogical characteristics in the Early Permian Shanxi Formation No. 3 coal from the Jinyuan Mine. The Jinyuan coal is a low ash and highly volatile A bituminous coal. Minerals in the No. 3 coal mainly comprise of kaolinite, ankerite, illite, calcite, siderite, and quartz, with varying compositions of trace amounts of pyrite, jarosite, bassanite, anatase, and rutile. According to mineral assemblage in the coal plies, three Types (A to C) can be identified in the No. 3 coal. The dominant minerals in Type A are poorly-ordered kaolinite, illite, quartz, pyrite, and jarosite. Type B is mainly composed of well-ordered kaolinite, illite, siderite, ankerite, and calcite. Type C, with just one sample (JY-3-7c), which contains high proportions of calcite (54%) and ankerite (34%). Terrigenous minerals are elevated in coal plies that typically have relatively high contents of ash yield. The formation of syngenetic pyrite was generally due to seawater, while the sulphate minerals (jarosite and coquimbite) were derived from the oxidation of pyrite. Epigenetic vein-like or fracture-fillings carbonate minerals (ankerite, calcite, and siderite), kaolinite, and pyrite, as well as authigenic quartz were derived from the influx of hydrothermal fluids during different periods, from the authigenic to epigenetic. The paragonite in the coal may have been formed by the precipitated from Na-rich hydrothermal fluids. No effects of magmatic intrusion on mineralogy were investigated in this research

The use of polydopamine for improving polymer flame retardancy

This thesis introduces a new method to utilize polydopamine (PDA) in flame retardancy.Three types of PDA are mentioned in this thesis: a) PDA nano-particles, b) PDA coating andc) PDA encapsulation.PDA nano-particle, a bio-flame retardant filler was synthesized through theself-polymerization of dopamine hydrochloride in alkaline solution, yielding nano-sizedpolydopamine (nano-PDA) particles ranging between 50 and 100 nm in diameters. Blendinga small amount (2 wt%) of the nano-PDA particles with epoxy can remarkably decrease thepeak heat release rate by 53.6%, exceeding the performance aluminum trihydroxide (ATH)particles at 10 wt%. The significant improvement in flame retardancy at a relatively lowloading of PDA has been found to originate from several key mechanisms including radicalscavenging, higher char yield, and production of CO2. Furthermore, the addition ofnano-PDA in the epoxy resin increased the tensile strength by ~ 6%. In contrast, the additionof common flame retardant, such as ATH, to achieve the same increase in flame retardancy ofepoxy would reduce the tensile strength by 28%. The enhancement of mechanical property ismainly due to the better bonding between PDA particles with epoxy than ATH with epoxy.PDA coating has proven to be a fire resistant layer on polyurethane (PU) foam outside. HNT& PDA hybrid coating was hypothesized to have synergetic effect between HNT and PDA inflame retardant applications. However, 10 wt% PDA coating on PU foam surface result in similar reduction of the peak heat release rate when compared to 20 wt% HNT & PDA hybridcoating, implying that there is no synergistic effect between the PDA coating and NHTparticles.PDA encapsulated ATH particles, synthesized via a self-polymerization of dopaminehydrochloride on ATH surface in alkaline condition, have been proved to improve the surfacemorphology of ATH particles which would improve the dispersibility of ATHs in polymer

Gut microbiota dysbiosis and decreased levels of acetic and propionic acid participate in glucocorticoid-induced glycolipid metabolism disorder

ABSTRACTLong-term/high-dose glucocorticoid (GC) use results in glycolipid metabolism disorder, which severely limits its clinical application. The role of the gut microbiota and its metabolites in GC-induced glycolipid metabolism disorder remains unclear. Our previous human study found that obvious gut microbiota dysbiosis characterized by an increasing abundance of Proteobacteria and a decreased abundance of Lachnospiraceae and Faecalibacterium were observed in patients with endogenous hypercortisolism. In this study, we established a mouse model of GC-induced glycolipid metabolism disorder (Dex group) and found that the relative abundances of Proteobacteria and Parasuttrerella were increased, while the abundances of Lachnospiraceae, Faecalibacterium, and Lachnospiraceae_NK4A136_group were decreased significantly in the Dex group. Compared with the control group, serum total short-chain fatty acids (SCFAs), acetic acid, propionic acid, and GLP-1 levels were all decreased in the Dex group. The mRNA expression of the GPR41 receptor and Pcsk1 in the colon was significantly decreased in the Dex group. Furthermore, GC-induced glycolipid metabolism disorder could be alleviated by depletion of the gut microbiota or fecal bacteria transplantation with control bacteria. The abundances of Lachnospiraceae_NK4A136_group and the serum GLP-1 levels were significantly increased, while the abundances of Proteobacteria and Parasutterella were significantly decreased after fecal bacteria transplantation with control bacteria. Our work indicates that gut microbiota dysbiosis and decreased levels of serum acetic acid and propionic acid may participate in GC-induced glycolipid metabolism disorder. These findings may provide novel insights into the prevention and treatment of GC-induced metabolic disorders.IMPORTANCEThe role of the gut microbiota in glucocorticoid (GC)-induced glycolipid metabolism disorder remains unclear. In our study, gut microbiota dysbiosis characterized by an increased abundance of Proteobacteria/Parasuttrerella and a decreased abundance of Lachnospiraceae_NK4A136_group was observed in mice with GC-induced glycolipid metabolism disorder. Some bacteria were shared in our previous study in patients with endogenous hypercortisolism and the mouse model used in the study. Furthermore, the depletion of the gut microbiota and fecal bacteria transplantation with control bacteria could alleviate GC-induced glycolipid metabolism disorder. Plasma acetic acid, propionic acid, and GLP-1 and the mRNA expression of the GPR41 receptor and Pcsk1 in the colon were decreased significantly in mice with GC-induced glycolipid metabolism disorder, which indicated that the gut microbiota/SCFA/GPR41/GLP-1 axis may participate in GC-induced glycolipid metabolism disorder. Our findings indicate that the gut microbiota may serve as a novel therapeutic target for GC-related metabolic disorders

Effects of waste coffee grounds on the mechanical properties, flame retardancy and toxic gas production of epoxy composites

Waste coffee grounds, a biomaterial with high carbon content, have been suggested as a non-toxic organic flame retardant due to their high char forming and radical scavenging properties. Herein, investigations are conducted on the effects of waste coffee grounds, especially their concentration and particle size, on the mechanical properties, flame retardancy, toxic gas production of epoxy composites. Results reveal that reducing average size of the waste coffee grounds from 46 µm to 16 µm, using freeze-milling or filtering, can reduce peak heat release rate and total heat release of their epoxy composites by 52.0% and 33.7% respectively, exceeding the effectiveness of other bio-based flame retardants such as chitosan, lignin and seashell. More importantly, the fine coffee grounds can achieve the same performance as aluminium trihydrates, the most widely used non-bio flame retardant. Furthermore, the burning rates and emissions of toxic gas have also been greatly reduced, almost entirely suppressing the highly toxic NO2 gas. The findings provide new insights into the effect of particle size of waste coffee grounds on both the mechanical properties and flame retardancy performnance of epoxy composites

Mineralogical characteristics of early permian paragonite-bearing coal (No. 3) in the Jinyuan Mine, Tengxian coalfield, Shandong Province, Eastern China

The Early Permian coal is of great value in the Tengxian Coalfield, Shandon Province, Eastern China. This work deals with the new data focusing on mineralogical characteristics in the Early Permian Shanxi Formation No. 3 coal from the Jinyuan Mine. The Jinyuan coal is a low ash and highly volatile A bituminous coal. Minerals in the No. 3 coal mainly comprise of kaolinite, ankerite, illite, calcite, siderite, and quartz, with varying compositions of trace amounts of pyrite, jarosite, bassanite, anatase, and rutile. According to mineral assemblage in the coal plies, three Types (A to C) can be identified in the No. 3 coal. The dominant minerals in Type A are poorly-ordered kaolinite, illite, quartz, pyrite, and jarosite. Type B is mainly composed of well-ordered kaolinite, illite, siderite, ankerite, and calcite. Type C, with just one sample (JY-3-7c), which contains high proportions of calcite (54%) and ankerite (34%). Terrigenous minerals are elevated in coal plies that typically have relatively high contents of ash yield. The formation of syngenetic pyrite was generally due to seawater, while the sulphate minerals (jarosite and coquimbite) were derived from the oxidation of pyrite. Epigenetic vein-like or fracture-fillings carbonate minerals (ankerite, calcite, and siderite), kaolinite, and pyrite, as well as authigenic quartz were derived from the influx of hydrothermal fluids during different periods, from the authigenic to epigenetic. The paragonite in the coal may have been formed by the precipitated from Na-rich hydrothermal fluids. No effects of magmatic intrusion on mineralogy were investigated in this research

Highly graphitized nitrogen-doped porous carbon nanopolyhedra derived from ZIF-8 nanocrystals as efficient electrocatalysts for oxygen reduction reactions

Nitrogen-doped graphitic porous carbons (NGPCs) have been synthesized by using a zeolite-type nanoscale metal–organic framework (NMOF) as a self-sacrificing template, which simultaneously acts as both the carbon and nitrogen sources in a facile carbonization process. The NGPCs not only retain the nanopolyhedral morphology of the parent NMOF, but also possess rich nitrogen, high surface area and hierarchical porosity with well-conducting networks. The promising potential of NGPCs as metal-free electrocatalysts for oxygen reduction reactions (ORR) in fuel cells is demonstrated. Compared with commercial Pt/C, the optimized NGPC-1000-10 (carbonized at 1000 °C for 10 h) catalyst exhibits comparable electrocatalytic activity via an efficient four-electron-dominant ORR process coupled with superior methanol tolerance as well as cycling stability in alkaline media. Furthermore, the controlled experiments reveal that the optimum activity of NGPC-1000-10 can be attributed to the synergetic contributions of the abundant active sites with high graphitic-N portion, high surface area and porosity, and the high degree of graphitization. Our findings suggest that solely MOF-derived heteroatom-doped carbon materials can be a promising alternative for Pt-based catalysts in fuel cells

Determination of Iron Active Sites in Pyrolyzed Iron-Based Catalysts for the Oxygen Reduction Reaction

Fe-based oxygen reduction reaction (ORR) catalyst materials are considered promising nonprecious alternatives to traditional platinum-based catalysts. These catalyst materials are generally produced by high-temperature pyrolysis treatments of readily available carbon, nitrogen, and iron sources. Adequate control of the structure and active site formation during pyrolysis methods is nearly impossible. Thus, the chemical nature, structure, and ORR mechanism of catalytically active sites in these materials is a subject of significant debate. We have proposed a method, utilizing CN^– ions as ORR inhibitors on Fe-based catalysts, to provide insight into the exact nature and chemistry of the catalytically active sites. Moreover, we propose two possible catalytically active site formation mechanisms occurring during high-temperature pyrolysis treatments, dependent on the specific type of precursor and synthesis methods utilized. We have further provided direct evidence of our proposed active site formations using ToF-SIMS negative and positive ion imaging. This knowledge will be beneficial to future work directed at the development of Fe-based catalysts with improved ORR activity and operational stabilities for fuel cell and battery applications