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1.
Marielle Christiansen Kjetil Fagerholt Truls Flatberg Øyvind Haugen Oddvar Kloster Erik H. Lund 《European Journal of Operational Research》2011
This paper considers a maritime inventory routing problem faced by a major cement producer. A heterogeneous fleet of bulk ships transport multiple non-mixable cement products from producing factories to regional silo stations along the coast of Norway. Inventory constraints are present both at the factories and the silos, and there are upper and lower limits for all inventories. The ship fleet capacity is limited, and in peak periods the demand for cement products at the silos exceeds the fleet capacity. In addition, constraints regarding the capacity of the ships’ cargo holds, the depth of the ports and the fact that different cement products cannot be mixed must be taken into consideration. A construction heuristic embedded in a genetic algorithmic framework is developed. The approach adopted is used to solve real instances of the problem within reasonable solution time and with good quality solutions. 相似文献
2.
3.
Hsu E. M. Mailman N. A. Botton G. A. Haugen H. K. 《Applied Physics A: Materials Science & Processing》2011,103(1):185-192
We present a structural investigation of single-crystal diamond following ultrafast laser irradiation of the surface and the
bulk material. Optical microscopy, atomic force microscopy, scanning electron microscopy, and focused-ion beam and transmission
electron microscopy techniques were utilized to selectively examine the final state of the samples. Laser induced periodic
surface structures (LIPSS) with high- and low-spatial frequencies were obtained with multiple-pulse surface irradiation under
both stationary and translated target conditions. High magnification transmission electron microscopy analysis of cross sections
of the LIPSS revealed modified layers of a few tens of nanometers in thickness capping the crystalline diamond matrix. Sub-surface
irradiation of diamond at high laser fluences led to damaged regions and cracks in the bulk material. When translational bulk
irradiation of the diamond was performed, substantially sub-wavelength periodic structures were observed at the unpolished
side facet of the diamond plate where the laser focus was translated out of the bulk. Spatial periods were 140 nm and the
structures largely consisted of single-crystal diamond with a 10 nm modified layer. Finally, preliminary studies of single-shot
laser ablation craters at high laser fluences exhibited suppression of material removal for peak values above 45 J/cm2. 相似文献
4.
M. Budiman E. M. Hsu H. K. Haugen G. A. Botton 《Applied Physics A: Materials Science & Processing》2010,98(4):849-853
Bulk irradiation of crystalline α-quartz was performed with ∼170-fs laser pulses with a wavelength of 800 nm focused below the sample surface. Investigations
were carried out using transmission electron microscopy on a cross-sectional specimen prepared using focused ion beam techniques.
We observed alternating amorphous–crystalline structures with sharp transitions and associated density changes, surrounded
by a highly strained crystalline structure. The alternating sub-surface structures are parallel to the laser’s electric field
polarization and exhibit a spacing which is close to the laser wavelength in air. Cracking was also observed in the near proximity
of these structures. 相似文献
5.
Under certain conditions the leading and trailing members of an acoustically deflected train can be spatially separated from the intermediate pulses. This is shown to be a simple and useful experimental technique for temporally cleaning up the output of a pulse-picked, mode-locked laser or cavity-dumped cw laser. In addition a physical model is described that explains the phenomenon. 相似文献
6.
Per Haugen Edward I. Hayes Hans-Henrik von Benzon 《Particle & Particle Systems Characterization》1994,11(1):63-72
Particles comparable in size to or larger than the measurement volume need extra consideration when measured by a phase-Doppler system. The phase of the Doppler burst received when such particles traverse the measurement volume depends not only on the size of the particle but also on its trajectory, since the particle is not uniformly illuminated. This paper presents a strategy for securing correct measurements even under such conditions, taking advantage of the three-detector receiving optics of the Dantec Particle Dynamics Analyzer. The effectiveness of the approach is demonstrated for sizing drops in liquid-gas and liquid-liquid two-phase flows: water drops in air, water drops in FC72 and FC72 drops in water. The combination of water and FC72 is also of interest because the relative refractive index is close to unity. Measurements of drops size were made on a monodisperse stream of drops about 2 mm in diameter, i.e. substantially larger than the measurement volume, and polydisperse distributions of drops ranging in diameter from below 0.2 mm to about 1 mm. 相似文献
7.
Irradiation of Si(1 0 0), Si(1 1 1), Si(1 1 0), Ge(1 0 0), and Ge(1 1 1) is compared for 150 fs, 800 nm wavelength pulses in a rough vacuum atmosphere. The surface crystalline orientation of the material is found to affect the final morphology, with (1 1 1)- and (1 1 0)-surface orientations exhibiting a much higher tendency for conical structure formation under multiple-pulse irradiation. Using cross-sectional transmission electron microscopy, the structures on Si(1 1 1) are found to have primarily crystalline cores with the same crystalline orientation as the substrate. The results show that the crystalline orientation of the target should be considered in laser machining applications. 相似文献
8.
Bragg gratings are used in several photonic devices to reflect, and thus to isolate, specific wavelengths of light. Gratings can be photoinduced in chalcogenide glasses by illumination of bandgap light in an interference pattern. We used holographic interferometry to create Bragg gratings in amorphous As2Se3 thin films with a period of 0.56 microm by illumination with 633-nm light. The quality of the gratings was tested in real time, and refractive-index modulations as high as 0.037 were measured. These gratings were found to be stable over a period of several months if they were kept in the dark. 相似文献
9.
Femtosecond laser pulse ablation of GaAs and InP: studies utilizing scanning and transmission electron microscopy 总被引:2,自引:0,他引:2
A. Borowiec M. MacKenzie G.C. Weatherly H.K. Haugen 《Applied Physics A: Materials Science & Processing》2003,77(3-4):411-417
Single pulse laser ablation of GaAs and InP using 130 fs light pulses at 800 nm was studied with various techniques, in particular, scanning and transmission electron microscopies. The final state of the material near the laser-ablated region following femtosecond ablation was characterized in detail for selected laser fluences. Threshold ablation laser fluences were also obtained for both compounds. PACS 61.80.Ba; 64.60.-i; 79.20.Ds 相似文献
10.
A. Borowiec M. MacKenzie G.C. Weatherly H.K. Haugen 《Applied Physics A: Materials Science & Processing》2003,76(2):201-207
The final state of the material resulting from laser irradiation of silicon using 130 fs pulses at 790 nm was studied using
a number of techniques including scanning and transmission electron microscopies, as well as atomic force microscopy. Structural
details and the level of damage to the nearby solid following irradiation were characterized and are discussed in the context
of recent dynamical studies.
Received: 28 September 2001 / Accepted: 3 March 2002 / Published online: 19 July 2002
RID="*"
ID="*"Department of Engineering Physics, McMaster University, Hamilton, Ontario, L8S 4M1, Canada
RID="**"
ID="**"Corresponding author. Fax: +1-905/521-2773, E-mail: borowia@mcmaster.ca
RID="***"
ID="***"Present address: Department of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
RID="****"
ID="****"Department of Materials Science and the CEMD, McMaster University, Hamilton, Ontario, L8S 4M1, Canada
RID="*****"
ID="*****"Departments of Engineering Physics, and Physics and Astronomy, and the CEMD, McMaster University, Hamilton, Ontario,
L8S 4M1, Canada 相似文献