The optical attenuation of fused silica glass impacted by high-speed micro-particle was studied. The high-speed impact test was carried out using a laser-driven flyer system which accelerated 16 ...μm-thick flyer to high speed of 3.7 km s
−1
. Scanning electron microscopy and optical microscopy were used to characterize the damage morphology of the impacted surface. The transmittance of the impacted glass samples was measured by means of UV/VIS double beam spectrophotometer. It was found that the transmittance of the impact region decreased due to the formation of structural defects such as crater, ejecta and micro-crack on the surface. A mathematic formula was established to explain the relationship between glass optical properties and the damaged modes, which aids to describe optical degradation and design long life optical equipments used in spacecrafts under space particles environment.
The reservoirs of the Upper Triassic Xujiahe Formation in Sichuan Basin have the characteristics of low compositional maturity, low contents of cements and medium textural maturity. The general ...physical properties of the reservoirs are poor, with low porosity and low permeability, and there are only a few reservoirs with medium porosity and low permeability in local areas. Based on the diagenetic mineral association, a diagenetic sequence of cements is established: early calcites (or micrite siderites) arrow right first quartz overgrowtharrow rightchlorite coatingsarrow rightdissolution of feldspars and debrisarrow rightchlorite liningsarrow rightsecond quartz overgrowth (quartz widen or filled in remain intergranular pores and solution pores)arrow rightdissolutionarrow rightthird quartz overgrowth (quartz filled in intergranular and intragranular solution pores)arrow rightintergrowth (ferro) calcitesarrow rightdolomitesarrow rightferro (calcites) dolomitesarrow rightlater dissolutionarrow rightveins of quartz and calcites formation. Mechanical compaction is the main factor in making the reservoirs tight in the basin, followed by the second and third quartz overgrowth. In a long-term closed system, only feldspars and some lithic fragments are dissolved by diagenetic fluids, while intergranular cements such as quartz and calcit are not dissolved and thus have little influence on the porosity of the Xujiahe Formation. This is the third factor that may have kept the sandstones of Xujiahe Formation tight finally. The hydrocarbon was extensively generated from organic materials after the second quartz overgrowth, and selectively entered favorable reservoirs to form tight sandstone gas reservoirs. PUBLICATION ABSTRACT
In the past two decades, an outpouring of Chinese scholarship on the millennium-long Ashkenazi Jewish presence in Shanghai and Harbin China has significantly advanced our understanding of Sino-Jewish ...relations and laid a solid foundation for further investigation of Chinese Jewish studies. This article is intended to move the conversation forward, from a predominantly Western-facing one to consider a persepective on Chinese Jewish studies that centers upon the Chinese experience of the thousand year presence of Judaism in its lands, rather than the single narrative of Jews acculturating in China.
Jewish studies develops fast in contemporary China. In a land which is neither Christian nor Muslim and where Judaism and the animus against it never developed substantial roots, what are the ...perceptible orientations within Jewish studies? What kinds of issues may Chinese scholars encounter when teaching and writing about Jews and Judaism? Does the unique context in which Jewish studies is emerging have a bearing upon Chinese practioners? And in what way is Chinese Jewish Studies different from that produced in other quarters of the world? Through a holistic review of Chinese Jewish Studies and three glimpses of Chinese Jewish scholarship with regard to the Jewish diaspora in China, the Holocaust and Biblical Studies, this paper tries to reflect on these questions in a comparative perspective.
Novel dendrite‐like silver particles were electrodeposited on Ti substrates from a supporting electrolyte‐free 30 mmol L−1 Ag(NH3)2+ solution, to synthesize the den‐Ag/Ti electrode. Binary AgxCoy/Ti ...electrodes with different Ag:Co atomic ratios were further obtained by electrodeposition of Co particles on the den‐Ag/Ti electrode. Polyaniline (PANI) modified den‐Ag/Ti and AgxCoy/Ti electrodes, PANI(n)‐den‐Ag/Ti and PANI(n)‐AgxCoy/Ti, were also obtained by cyclic voltammetry at different numbers of cycles (n) in acidic and alkaline solutions containing aniline, respectively. All these electrodes exhibit high electroactivity for oxygen reduction reaction (ORR) in alkaline solution and their electroactivities follow the order: PANI(15)‐Ag31Co69/Ti>Ag31Co69/Ti>PANI(20)‐den‐Ag/Ti>den‐Ag/Ti. Among them, PANI(15)‐Ag31Co69/Ti displays the highest electrocatalytic activity for ORR with a much positive onset potential of 0 V (vs. Ag/AgCl) and a high ORR current density of 1.2 mA cm−2 at −0.12 V (vs. Ag/AgCl). The electrocatalysts are electrochemically insensitive to methanol and ethanol oxidation, and, as cathode electrocatalysts of direct alcohol fuel cells, can resist poisoning by the possible alcohol crossover from the anode.
Testate amoebae contribute significantly to belowground ecological processes like nutrient cycling, but a decline in their nutrient cycling functions in peatlands is expected due to global climate ...warming. We studied the dynamics of testate amoebae communities in relation to soil environmental variables in a permafrost peatland that experienced in situ experimental warming for a 7-yr period. Experimental warming reduced testate amoebae biomass by 41%. Redundancy analyses showed that testate amoebae community structure was correlated with water table depth and soil temperature (these explained 10% of the variance in community structure) and dissolved organic carbon (which explained 2.2% of the variance). Our results demonstrated that warming-induced changes to the water table depth affected the testate amoebae community in peatland, which could have consequences for the stability of the microbial food web and carbon cycling in peatland ecosystems.
•Experimental warming reduced testate amoebae biomass by 41% in boreal peatlands.•Heterotrophic testate amoebae were vulnerable to experimental warming.•Testate amoebae dynamics were associated with water table depth in warmed peatlands.
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•The adsorption mechanism of Li2S on VS and VSe are calculated.•A strong Eb is beneficial for controlling uniform deposition of Li2S on VX.•VS and VSe are promising cathode materials ...for Li-S batteries.
Both the shuttle effect of long-chain polysulfides and the non-uniform deposition of short-chain polysulfides upon the surface of a cathode will reduce the usage rate of active materials and restrict the large-scale production of lithium-sulfur (Li-S) batteries. Here, a first-principles calculation was employed to systematically determine and investigate the potential application of VX (X = S, Se) as an anchoring material for Li-S batteries. The adsorption energy, density of state, charge transfer, and difference-charge density were calculated. It is apparent that there are charges transfer between Li2S and VX, and the chemical-adsorption energies of Li2S on VX are strong. The interaction between the S atom of Li2S and the surface V atom of VX is the origin of anchoring; moreover, the diffusion behavior of Li ions on the VX surface was studied, and the diffusion barrier was found to be relatively low. The results demonstrate that VS and VSe may act as excellent anchoring materials for high-efficiency Li-S batteries.
This study combined three different data sources, the Global Entrepreneurship Monitor (GEM), Index of Economic Freedom (IEF) and World Development Indicator (WDI) to examine the relationships between ...three dimensions of the country-level institutional environment (i.e., regulatory, cognitive, and normative) and two types of hospitality entrepreneurship (opportunity-based vs. necessity-driven). Logit regression analyses on a multi-sourced dataset indicate that the three dimensions of institutional environment had different effects on hospitality entrepreneurship. Specifically, the regulatory dimension positively affected opportunity-based entrepreneurship; however, its effect on necessity entrepreneurship was negative. In contrast, the normative dimension had a negative effect on opportunity entrepreneurship and a positive effect on necessity entrepreneurship. The cognitive dimension had no significant relationship with either opportunity or necessity entrepreneurship in the hospitality sector.
•Three different data sources, GEM, IEF and WDI were used to test the research framework•The impact from the country-level institutional environment on hospitality entrepreneurship was examined•Regulatory dimension positively affected opportunity-based entrepreneurship and negatively affected necessity entrepreneurship•Normative dimension had a negative effect on opportunity entrepreneurship and a positive effect on necessity entrepreneurship•Cognitive dimension had no significant relationship with either opportunity or necessity entrepreneurship
Extant studies of environmental investment determinants have not distinguished between different types of political connections. This study tries to close this gap by employing an extensive dataset ...based on the four-yearly Chinese Private Enterprises Survey conducted between 2006 and 2012. The central question in this paper asks whether different political connections (ascribed vs. achieved) are fostering or hindering environmental protection expenditures in private enterprises. The results show that achieved political connections serve as binds of promoting firm environmental investment while ascribed political connections act as buffers, hampering firm environmental expenditures. The moderating roles of environmental regulation and innovation capability demonstrate heterogeneous effects: environmental regulation stringency strengthens the positive impact of achieved political connections only. In contrast, innovation capability enhances the negative impact of ascribed political connections.
