Sub-wavelength and non-periodic holes array based fully lensless imager

We present a novel concept for microscopic imaging. The proposed microscope-like device does not include an objective lens neither a condenser. Instead, a metallic plate of sub-wavelength hole-array with a varying pitch is used to illuminate the inspected object that is mounted very close to it. As a result, the transmitted spectrum through each hole differs from the others and therefore, each spot of the detected object is illuminated with a unique spectrum. By measuring a single spectrum that is the sum of all the spectra that are transmitted through the sample and by using spectral decomposition algorithms, the spatial transmission pattern of the object can be extracted.     

Minmax scheduling with job-classes and earliness–tardiness costs

We address scheduling problems with job-dependent due-dates and general (possibly nonlinear and asymmetric) earliness and tardiness costs. The number of distinct due-dates is substantially smaller than the number of jobs, thus jobs are partitioned to classes, where all jobs of a given class share a common due-date. We consider the settings of a single machine and parallel identical machines. Our objective is of a minmax type, i.e., we seek a schedule that minimizes the maximum earliness/tardiness cost among all jobs.     

Methane adsorption on microporous carbon adsorbent with wide pore size distribution

Methane adsorption on a microporous carbon adsorbent with a bimodal pore size distribution is studied at temperatures of 303–333 K at pressures up to 30 MPa. The total micropore volume of the adsorbent, as determined by the Dubinin method, is as large as 1.02 cm³/g. Maximum values of methane adsorption of ≈18 mmol/g are attained at a temperature of 303 K and a pressure of 30 MPa. Methane adsorption isosteres are plotted based on experimental data, and adsorption equilibria at low temperatures are calculated using the linearity of the plots. Experimental isotherms of methane adsorption are compared with the isotherms calculated by the Dubinin–Nikolaev equation with variations in parameters E and n. Temperature dependences of these parameters are determined. Specific characteristics of methane adsorption accumulation are calculated.     

Analysis of porous structure of furfurol-based active carbons with application of the density functional theory

Isotherms of nitrogen low-temperature adsorption on active FAS carbons and coconut-shell carbons were studied by the method of the density functional nonlocal theory. Distribution curves of micropore volumes in their width were obtained.m dodecyl sulfate in the presence of hydrogen peroxide under the action of UV light was studied.     

On the core and nucleolus of minimum cost spanning tree games

We develop two efficient procedures for generating cost allocation vectors in the core of a minimum cost spanning tree (m.c.s.t.) game. The first procedure requires O(n ²) elementary operations to obtain each additional point in the core, wheren is the number of users. The efficiency of the second procedure, which is a natural strengthening of the first procedure, stems from the special structure of minimum excess coalitions in the core of an m.c.s.t. game. This special structure is later used (i) to ease the computational difficulty in computing the nucleolus of an m.c.s.t. game, and (ii) to provide a geometric characterization for the nucleolus of an m.c.s.t. game. This geometric characterization implies that in an m.c.s.t. game the nucleolus is the unique point in the intersection of the core and the kernel. We further develop an efficient procedure for generating fair cost allocations which, in some instances, coincide with the nucleolus. Finally, we show that by employing Sterns' transfer scheme we can generate a sequence of cost vectors which converges to the nucleolus. Part of this research was done while the author was visiting the Department of Operations Research at Stanford University. This research was partially supported by Natural Sciences and Engineering Research Council Canada Grant A-4181.     

Stability of lyophobic sols

The coagulation of positively charged sol of hydrous ferric oxide of different average particle sizes for potassium sulphate as the coagulant has been studied in the presence of ethyl alcohol, acetone and gelatin. It has been observed that these sensitise the sol and the degree of sensitisation increases with the fineness of dispersed particles. It has been concluded that the adhesive tendency of the surface of dispersed particles increases in the presence of said non-electrolytes leading to an increase in the frequency of collisions resulting in sensitisation. The stability ratioW decreases in the presence of said non-electrolytes for the same amount of coagulant.     

System for recording and analysis of reflection high-energy electron diffraction patterns

An efficient and fast system for recording and analysis of reflection high-energy electron diffraction (RHEED) patterns is described. The software developed for this system includes three program packages: one for operating in the single-window mode, one for operating in the four-window mode, and one for the linear regime. Examples are given of the use of the system for monitoring and control of growth of III–V semiconductor compounds by molecular-beam epitaxy. Using this system, we discovered an effect wherein a periodic splitting of the RHEED peaks occurs during the growth of GaAs (100). Zh. Tekh. Fiz. 67, 111–116 (August 1997)     

Error bounds for the aggregated convex programming problem

Applied mathematical programming problems are often approximations of larger, more detailed problems. One criterion to evaluate an approximating program is the magnitude of the difference between the optimal objective values of the original and the approximating program. The approximation we consider is variable aggregation in a convex program. Bounds are derived on the difference between the two optimal objective values. Previous results of Geoffrion and Zipkin are obtained by specializing our results to linear programming. Also, we apply our bounds to a convex transportation problem. Thanks are due to Ron Dembo, Paul Zipkin and the referees for valuable comments. This research was supported by NSF Grant ENG-76-15599.     

Due-window assignment with identical jobs on parallel uniform machines

A scheduling problem with a common due-window, earliness and tardiness costs, and identical processing time jobs is studied. We focus on the setting of both (i) job-dependent earliness/tardiness job weights and (ii) parallel uniform machines. The objective is to find the job allocation to the machines and the job schedule, such that the total weighted earliness and tardiness cost is minimized. We study both cases of a non-restrictive (i.e. sufficiently late), and a restrictive due-window. For a given number of machines, the solutions of the problems studied here are obtained in polynomial time in the number of jobs.