The W/O xanthan fermentation is simulated by integrating the microbial kinetic behaviors and the multiple-phase process characteristics. Model 1 assumes uniform redistribution of cells, substrates and product by frequent droplet breakup and coalescence. Model 2 simulates the system of viscous aqueous phase with minimal droplet breakup and component redistribution. The real fermentation should proceed within the bounds set by the two models. Effects of various parameters are evaluated. The aqueous-phase xanthan concentration (Xn) and volumetric productivity (QP) achieved at 200 h are used as the indicators. Xn and QP increase with nitrogen-source concentration (SNO) initially but plateau (Model 1) or decrease slightly (Model 2) at high SNO. Xn (at 200 h) decreases with increasing aqueous-phase volume fraction (f). QP, however, increases with f reflecting its basing on the total dispersion volume. Increasing agitation and aeration result in higher Xn and QP. The higher agitation enhances the G/O interfacial oxygen transfer and reduces the droplet size. Increasing aeration improves the G/O interfacial transfer but increases the droplet size. Its net positive effect implies a rate-limiting step at G/O interface. The W/O fermentation can produce far higher Xn (> 200 kg/m3) and QP( > 0.8 kg/m3-h) than the conventional fermentation (Xn ~ 50 kg/m3, QP ~ 0.5 kg/m3-h). 相似文献
An analogue-oriented synthetic route for the formulation of furazan-functionalized 5-nitroimino-1,2,4-triazoles has been explored. The process was found to be straightforward, high yielding, and highly efficient, and scalable. Nine compounds were synthesized and the physicochemical and energetic properties, including density, thermal stability, and sensitivity, were investigated, as well as the energetic performance (e.g., detonation velocities and detonation pressures) as evaluated by using EXPLO5 code. Among the new materials, compounds 4 – 6 and 11 possess high densities, acceptable sensitivities, and good detonation performances, and thereby demonstrate the potential applications as new secondary explosives. 相似文献
Aspirin (abbr. ASA) is intercalated into the layered terbium hydroxide (LTbH) by anion exchange method. Structure, chemical compositions, thermostability, morphology, luminescence property, cytotoxic effects and controlled‐release behaviors have been investigated. The ASA molecules may embed between layers with monolayered vertical arrangement, and the thermal stability of organics was enhanced after intercalation. The Tb3+ luminescence in ASA‐LTbH composites was enhanced compared with LTbH precusor and the luminescence intensity increased with the deprotonation degree. The cytotoxic effect of LTbH was observed with a sulforhodamine B (SRB) colorimetric assay, which revealed that the LTbH showed low cytotoxic effects. In addition, the ASA‐LTbH composites exhibited a sustained release of ASA in Na2HPO4‐NaH2PO4 buffer solution at pH 6.86 and 37°C. Construction of LRHs composites with drug molecules provided a beneficial pathway for preparing biohybrid based on LRHs, which may have potential applications in drug delivery carrier and biological fluorescence probe. 相似文献
Accidental leakage of automobile oils is of great inclination to initiate pool fires in engine compartment, with threats to induce the flashover of other components and flame penetration into the passenger compartment. This paper presents experimental results of the ignition and burning behaviors of a kind of automobile oils (automatic transmission oil) using a cone calorimeter. Measurements of oil temperature, ignition time, mass loss and heat release rate are performed at different external heat fluxes and initial fuel depths. The comparison between experimental and numerical oil temperature evolutions shows that the variations of the ignition time at different experimental conditions depend on the heat dissipation process inside the liquid phase. The steady mass burning rate is nearly independent of initial fuel depth and has a linear relation with external heat fluxes. In addition, the results indicate an increase in peak heat release rate by a large margin initially, followed by a relatively small margin under thicker initial fuel depths, while its variations are proportional to external heat fluxes. Correlations are also developed to determine the peak heat release rate as a function of the initial fuel depth.
Nanofabrication is an indispensable process in nanoscience and nanotechnology. Unconventional lithographic techniques are often used for fabrication as alternatives to photolithography because they are faster, more cost‐effective, and simpler to use. However, these techniques are limited in scalability and utility because of the collapse of preprinted structures during step‐and‐repeat processes. This study proposes a new class of temperature‐controllable polymeric molds that are coated with a metal such that any site‐specific patterning can be accomplished in a programmable manner using selective contact‐dewetting lithography. The lithography allows sub‐100 nm patterning, step‐and‐repeat processing, and hierarchical structure fabrication. The programmable feature of the lithography can be utilized for the structural coloring and shaping of objects. Large‐area programmable patterning, semiconductor device manufacturing, and the fabrication of iridescent security devices would benefit from the unique features of the proposed strategy. 相似文献
In this paper, we mainly studied the limit properties for the
countable nonhomogeneous Markov chains. We established some limit properties for the
functions of the countable nonhomogeneous Markov chains with variables under the
convergence in the sense, which extended the similar conclusions for the
functions with two variables. At last, as a corollary, we given the similar result in
the homogeneous Markov stock market. 相似文献
An array of coupled cavities, each of which contains a triangle-down-level atom, is investigated. An effective Hamiltonian can be achieved under the strong classical driving. We can control the transition between Mott-insulator and superfluid states by the classical driving. The frequency conversion in one site has the same effects of nonlinear in BH hamiltonian which can induce insulator-superfluid states. 相似文献