This paper considers a two-machine ordered flow shop problem, where each job is processed through the in-house system or outsourced to a subcontractor. For in-house jobs, a schedule is constructed and its performance is measured by the makespan. Jobs processed by subcontractors require paying an outsourcing cost. The objective is to minimize the sum of the makespan and the total outsourcing cost. Since this problem is NP-hard, we present an approximation algorithm. Furthermore, we consider three special cases in which job j has a processing time requirement pj, and machine i a characteristic qi. The first case assumes the time job j occupies machine i is equal to the processing requirement divided by a characteristic value of machine i, that is, pj/qi. The second (third) case assumes that the time job j occupies machine i is equal to the maximum (minimum) of its processing requirement and a characteristic value of the machine, that is, max{pj, qi} (min{pj, qi}). We show that the first and the second cases are NP-hard and the third case is polynomially solvable. 相似文献
We study the dynamical invariant for dissipative three coupled oscillators mainly from the quantum mechanical point of view. It is known that there are many advantages of the invariant quantity in elucidating mechanical properties of the system. We use such a property of the invariant operator in quantizing the system in this work. To this end, we first transform the invariant operator to a simple one by using a unitary operator in order that we can easily manage it. The invariant operator is further simplified through its diagonalization via three-dimensional rotations parameterized by three Euler angles. The coupling terms in the quantum invariant are eventually eliminated thanks to such a diagonalization. As a consequence, transformed quantum invariant is represented in terms of three independent simple harmonic oscillators which have unit masses. Starting from the wave functions in the transformed system, we have derived the full wave functions in the original system with the help of the unitary operators. 相似文献
The evolution of bond structure of laser deposited Ge33As12Se55 films under various processing conditions has been investigated by X-ray photoelectron spectroscopy. It was found that a large number of Se-rich structures in the as-grown film may coalesce with As and Ge after annealing at high temperatures. In addition, both Ge and As 3d spectra show the presence of oxides. The oxygen distribution exponentially decays along the normal direction of the films regardless of different processing conditions. The critical thickness of the oxidized layer was extracted for the film annealed at various pressures and temperatures. 相似文献
A variety of shapes, such as rod, tripod, -shape and cube, of Au nanocrystals were synthesized by employing different reaction conditions. The nanocrystals and their shape variation were characterized by transmission electron microscopy and UV–vis spectrophotometry. The evolution of shape was accomplished by controlling the parameters used in their synthesis, the concentration of reducing agent and surface capping agent. The effect of synthetic parameters on shape was explored, to determine suitable conditions for producing each shape of nanocrystals. Nanocrystals with different shapes have different plasmon bands in the visible region of the spectrum, which is a valuable property for sensor applications. 相似文献
1-Methyl-3,4-dihydroquinoxalin-2(1H)-one was heated with a range of aldehydes to generate intermediate azomethine ylides which underwent [3 + 2] cycloaddition reactions with N-methyl or N-phenylmaleimide to give substituted tetrahydropyrroloquinoxalinones. Only one (racemic) stereoisomer was formed in each case and the stereochemical outcome was verified by single crystal X-ray analysis. The products from this multicomponent reaction could be oxidised with DDQ to the pyrroloquinoxalinones. 相似文献
Microglia, the brain‐resident macrophage, are involved in brain development and contribute to the progression of neural disorders. Despite the importance of microglia, imaging of live microglia at a cellular resolution has been limited to transgenic mice. Efforts have therefore been dedicated to developing new methods for microglia detection and imaging. Using a thorough structure–activity relationships study, we developed CDr20, a high‐performance fluorogenic chemical probe that enables the visualization of microglia both in vitro and in vivo. Using a genome‐scale CRISPR‐Cas9 knockout screen, the UDP‐glucuronosyltransferase Ugt1a7c was identified as the target of CDr20. The glucuronidation of CDr20 by Ugt1a7c in microglia produces fluorescence. 相似文献
An effective electrochemical reduction of nitrous oxide (N2O) is established by controlling solution compositions in this study. N2O was electrochemically reduced varying solvent composition and supporting electrolytes (K2SO4 and Na2SO4) concentrations. The differences in reduction current density and solution resistance were analyzed via linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS), respectively, depending on solution conditions. UV‐Vis spectroscopy was adopted to measure the solubility of N2O. As a result, among the conditions investigated in this study, 300 mM of K2SO4 and aqueous based solution were revealed as an optimum condition for the electrochemical N2O reduction. At 300 mM of K2SO4, the highest current density was obtained due to a high conductance of the electrolyte and a moderate solubility of N2O. 相似文献
Starch is one of the main carbohydrates in food; it is formed by two polysaccharides: amylose and amylopectin. The granule size of starch varies with different botanical origins and ranges from less than 1 μm to more than 100 μm. Some physicochemical and functional properties vary with the size of the granule, which makes it of great interest to find an efficient and accurate size-based separation method. In this study, the full-feed depletion mode of split-flow thin cell fractionation (FFD-SF) was employed for a size-based fractionation of two types of starch granules (corn and potato) on a large scale. The fractionation efficiency (FE) of fraction-a for corn and potato granules was 98.4 and 99.4%, respectively. The FFD-SF fractions were analyzed using optical microscopy (OM) and gravitational field-flow fractionation (GrFFF). The respective size distribution results were in close agreement for the corn starch fractions, while they were slightly different for the potato starch fractions. The thermal properties of FFD-SF fractions were analyzed, and the results for the potato starch showed that the peak temperature of gelatinization (Tp) slightly decreases as the size of the granules increases. Additionally, the enthalpy of gelatinization (ΔH) increases when the granule size increases and shows negative correlation with the gelatinization range (ΔT).
The surface of poly(dimethylsiloxane) (PDMS) is grafted with poly(acrylic acid) (PAA) layers via surface‐initiated photopolymerization to suppress the capsular contracture resulting from a foreign body reaction. Owing to the nature of photo‐induced polymerization, various PAA micropatterns can be fabricated using photolithography. Hole and stripe micropatterns ≈100‐µm wide and 3‐µm thick are grafted onto the PDMS surface without delamination. The incorporation of PAA micropatterns provides not only chemical cues by hydrophilic PAA microdomains but also topographical cues by hole or stripe micropatterns. In vitro studies reveal that a PAA‐grafted PDMS surface has a lower proliferation of both macrophages (Raw 264.7) and fibroblasts (NIH 3T3) regardless of the pattern presence. However, PDMS with PAA micropatterns, especially stripe micropatterns, minimizes the aggregation of fibroblasts and their subsequent differentiation into myofibroblasts. An in vivo study also shows that PDMS samples with stripe micropatterns polarized macrophages into anti‐inflammatory M2 macrophages and most effectively inhibits capsular contracture, which is demonstrated by investigation of inflammation score, transforming‐growth‐factor‐β expression, number of macrophages, and myofibroblasts as well as the collagen density and capsule thickness. 相似文献
An iterated improved reduced system (IIRS) procedure combined with substructuring scheme for both undamped and nonclassically damped structures is presented. Iterated IIRS method is an efficient reduction technique because the highly accurate eigenproperties from the repeatedly updated condensed matrices can be obtained without consuming expensive computational cost. However, single domain direct approach of this method to large structures requires much computational resources and even makes analysis intractable in the case only limited computer storage is available. These problems can be overcome by combining the substructuring scheme with IIRS procedure. The newly developed IIRS method combined with a substructuring scheme can provide an efficient methodology for large-scale eigenvalue problems. The validation of the present method and the evaluation of computational efficiency are demonstrated through the numerical examples. 相似文献