Ethyl 2-[(tert-but­oxy­carbon­yl)amino]­thia­zole-5-carboxyl­ate

In the crystal of the title compound, C11H16N2O4S, molecules are linked via pairs of N—H⋯N hydrogen bonds to form inversion dimers. The dimers are linked by a weak C—H⋯O interaction to form chains propagating along direction [100]

Persistent Flows in Deterministic Chains

This paper studies the role of persistent flows in the convergence of infinite backward products of stochastic matrices of deterministic chains over networks with non-reciprocal interactions between agents. An arc describing the interaction strength between two agents is said to be persistent if its weight function has an infinite l1 norm; convergence of the infinite backward products to a rank-one matrix of a deterministic chain of stochastic matrices is equivalent to achieving consensus at the node states. We discuss two balance conditions on the interactions between agents which generalize the arc-balance and cut-balance conditions in the literature, respectively. The proposed conditions require that such a balance should be satisfied over each time window of a fixed length instead of at each time instant. We prove that in both cases global consensus is reached if and only if the persistent graph, which consists of all the persistent arcs, contains a directed spanning tree. The convergence rates of the system to consensus are also provided in terms of the interactions between agents having taken place. The results are obtained under a weak condition without assuming the existence of a positive lower bound of all the nonzero weights of arcs and are compared with the existing results. Illustrative examples are provided to validate the results and show the critical importance of the nontrivial lower boundedness of the self-confidence of the agents

Heat Transfer and Failure Mode Analyses of Ultrahigh-Temperature Ceramic Thermal Protection System of Hypersonic Vehicles

The transient temperature distribution of the ultrahigh-temperature ceramic (UHTC) thermal protection system (TPS) of hypersonic vehicles is calculated using finite volume method. Convective cooling enables a balance of heat increment and loss to be achieved. The temperature in the UHTC plate at the balance is approximately proportional to the surface heat flux and is approximately inversely proportional to the convective heat transfer coefficient. The failure modes of the UHTCs are presented by investigating the thermal stress field of the UHTC TPS under different thermal environments. The UHTCs which act as the thermal protection materials of hypersonic vehicles can fail because of the tensile stress at the lower surface, an area above the middle plane, and the upper surface as well as because of the compressive stress at the upper surface. However, the area between the lower surface and the middle plane and a small area near the upper surface are relatively safe. Neither the compressive stress nor the tensile stress will cause failure of these areas

Two new species of Feroperis Lafer (Carabidae, Pterostichus) from China, with a key to all known Chinese species in this subgenus

Two new Pterostichus species (Coleoptera, Carabidae) in the subgenus Feroperis Lafer, 1979 are described from Zhangguangcai Mountain, northeastern China: Pterostichus (Feroperis) silvestris Sun & Shi, sp. n. and Pterostichus (Feroperis) maryseae Sun & Shi, sp. n. Detailed descriptions and illustrations of the male endophallus and female reproductive tracts for these new species are provided, along with a key to the five known species of the subgenus in China

Magnetic properties and geochemistry of the Xiashu Loess in the present subtropical area of China, and their implications for pedogenic intensity

Abstract Variations in the magnetic susceptibility of Chinese loess have been used to indicate pedogenic intensity and therefore past climate across the Chinese Loess Plateau (CLP). However, the relationship between climate and magnetic properties has not been fully resolved, and therefore a study of loess sections distributed over a wider climatic region is timely. In this study, we have investigated a 22.1 m loess section (named the Xiashu Loess) at Dagang, China, by integrating both rock magnetic and geochemical proxies. This loess profile is situated in a modern subtropical climate region with annual mean precipitation and temperature of 1100 mm and 15.4°C, respectively, and therefore has experienced a stronger weathering intensity due to its lower latitude, higher temperature and rainfall. Geochemical and magnetic evidence indicate the same source area for the Xiashu Loess as for loess in northern China. The magnetic mineral assemblage of the Xiashu Loess is dominated by a higher concentration of superparamagnetic (SP)/single domain (SD) magnetite/maghemite grains in strongly weathered paleosols than in the loess layers, consistent with the production of fine-grained ferrimagnetic minerals during pedogenic processes. Nevertheless, compared to loess in the CLP, the Xiashu Loess shows: 1) reduced contrasts in magnetic susceptibility (χ), Hard Isothermal Remanent Magnetization (HIRM) and remanence of coercivity (B cr ) between loess and paleosols units, which indicates that the loess units have undergone stronger pedogenic alterations; 2) lower peak values of HIRM and χ in paleosols. In addition, the ratios SIRM/χ, χ ARM /SIRM (where SIRM and χ ARM are Saturation Isothermal Remanent Magnetization and the susceptibility of Anhysteretic Remanent Magnetization, respectively) and B cr are found to be significantly correlated with the quotient (CaO ⁎ + Na 2 O + MgO)/TiO 2 , a geochemical indicator of pedogenic intensity. Overall, it seems that pedogenic processes in the Xiashu Loess lead to a relative increase in fine-grained ferrimagnetic SP/SD grains but depletion of anti-ferromagnetic minerals. Magnetic and geochemical proxies indicate strengthened East Asia summer monsoon during Marine Isotope Stages 13, 11 and 5, which is in good agreement with the records from the CLP and the South China Sea