Optimization of the Advanced Earth Observing Satellite II Global Imager channels by use of radiative transfer calculations

The channel specifications of the Global Imager onboard the Advanced Earth Observing Satellite II have been determined by extensive numerical experiments. The results show that there is an optimum feasible position for each ocean color channel. The bandwidth of the 0.763-microm channel should be less than 10 nm for good sensitivity to the cloud top height and geometric thickness of the cloud layer; a 40-nm bandwidth is suitable for the 1.38-microm channel to have the strongest contrast between cloudy and clear radiance with a sufficient radiant energy; and a 3.7-microm channel is better than a 3.95-microm channel for estimation of the sea surface temperature (SST) and determination of the cloud particle size when the bandwidth of the channel is 0.33 microm. A three-wavelength combination of 6.7, 7.3, and 7.5 microm is an optimized choice for water vapor profiling. The combination of 8.6, 10.8, and 12.0 microm is suitable for cloud microphysics and SST retrievals with the split-window technique.     

Dynamic single-mode semiconductor lasers with a distributed reflector

Recent progress in the dynamic single-mode (DSM) semiconductor lasers in the wavelength of1.5-1.6mum are reviewed and the basic principle of DSM operation is given. Study of the DSM laser is originated for application to the wide-band optical-fiber communication in the lowest loss wavelength region of 1.5 to 1.65 μm. A DSM laser consists of a mode-selective resonator and a transverse-mode-controlled waveguide, such as the narrow-striped distributed-Bragg-reflector (DBR) laser, so as to maintain a fixed axial mode under the rapid direct modulation. The technology of monolithic integration for optical circuits is applied to realize some of DSM lasers. Structures, static and dynamic characteristics of lasing wavelength, output power, and reliability of the art DSM lasers are reviewed. The dynamic Spectral width of 0.3 nm, the output power of a few milliwatts, and the reliability over a few thousand hours are reported for experimental DSM lasers.     

On tangible user interfaces,humans and spatiality

Like the prehistoric twig and stone, tangible user interfaces (TUIs) are objects manipulated by humans. Tangible user interface success will depend on how well they exploit spatiality, the intuitive spatial skills humans have with the objects they use. In this paper, we carefully examine the relationship between humans and physical objects, and related previous research. From this examination, we distill a set of observations and turn these into heuristics for incorporation of spatiality into TUI application design, a cornerstone for their success. Following this line of thought, we identify spatial TUIs, the subset of TUIs that mediate interaction with shape, space and structure. We then examine several existing spatial TUIs using our heuristics.     

Analysis of threshold current density of CdZnSe/ZnSSe strained well lasers

The threshold current density (J/sub th/) of blue-green CdZnSe/ZnSSe strained quantum well lasers is analysed using the laser theory established for III-V semiconductor lasers. Very good agreement between theory and the reported experimental J/sub th/ values is obtained over a wide temperature range from 77 to 273 K. The optimal Cd composition of a CdZnSe single quantum well active layer for obtaining a low J/sub th/ value at room temperature is in the range 0.25-0.30.<>     

Characterization of deep levels in Si‐MOS structure using ICTS measurement

Interface traps and bulk traps induced by heavy metal impurities in Si‐MOS structure were characterized by isothermal capacitance transient spectroscopy (ICTS). In addition, the use of an MOS inversion time is proposed for the detection of a very low density of heavy metal impurities in the ICTS measurements. It is shown that heavy metal impurities enhanced interface trap densities as well as induced bulk traps. The degree of the enhancement varies with the species of heavy metal impurities. Interface traps may be enhanced by the substitutional heavy metal impurities. Moreover, it has been ascertained that a very low level of contamination by heavy metals can be detected by using the MOS inversion time. This has been experimentally shown by the use of a copper impurity. Furthermore, it has been clarified from the change of MOS inversion time that interface traps are also detrimental to the carrier generation lifetime. © 2000 Scripta Technica, Electr Eng Jpn, 130(4): 76–86, 2000     

Variable bit-rate coding of video signals for ATM networks

Statistical characteristics of video signals for video packet coding, are clarified and a variable-bit-rate coding method for asynchronous transfer mode (ATM) networks is described that is capable of compensating for packet loss. ATM capabilities are shown to be greatly affected by delay, delay jitter, and packet loss probability. Packet loss has the greatest influence on picture quality. Packets may be lost either due to random bit error in a cell header or to network control when traffic is congested. A layered coding technique using discrete-cosine transform (DCT) coding is presented which is suitable for packet loss compensation. The influence of packet loss on picture quality is discussed, and decoded pictures with packet loss are shown. The proposed algorithm was verified by computer simulations     

Optimizing gettering conditions for VLSI chips using simple yieldmodel

Conditions of an effective gettering procedure for VLSI processing are investigated by means of analytical simulation. The effectiveness of a gettering procedure is judged from the VLSI yield when the density of heavy metal impurities and gettering capability are varied over a wide range. It is found that the VLSI yield is seriously degraded by the negative effects of gettering, namely, wafer warpage and dislocation propagation from a gettering site region to a device area. It is seen that gettering effects are profitable in VLSI processes only when the density of heavy metal impurity to be removed is not too high     

Low threshold current density operation of GaInP-AlGaInP visiblemultiple quantum wire-like lasers (MQWR-LDs) under the room temperaturepulsed condition

GaInP-AlGaInP multiple quantum wire-like layers were fabricated by the in situ strain induced lateral layer ordering process during MBE growth. According to TEM images, the quantum wire size was around 10 nm and quantum wire axis was along [011¯] direction. When we made laser diodes with stripes along [011] direction, the low threshold current density, of 315 A/cm² was obtained. Anisotropic lasing characteristics between [011] and [011¯] directions, in threshold current density, lasing mode, and lasing wavelength were observed     

Conjugated linoleic acid production from linoleic acid by lactic acid bacteria

After screening 14 genera of lactic acid bacteria, Lactobacillus plantarum AKU 1009a was selected as a potential strain for CLA production from linoleic acid. Washed cells of L. plantarum with high levels of CLA production were obtained by cultivation in a nutrient medium with 0.06% (wt/vol) linoleic acid (cis-9,cis-12-octadecadienoic acid). Under the optimal reaction conditions with the free form of linoleic acid as the substrate, washed cells of L. plantarum produced 40 mg CLA/mL reaction mixture (33% molar yield) from 12% (wt/vol) linoleic acid in 108 h. The resulting CLA was a mixture of two CLA isomers, cis-9,trans-11 (or trans-9,cis-11)-octadecadienoic acid (CLA1, 38% of total CLA) and trans-9,trans-11-octadecadienoic acid (CLA2, 62% of total CLA), and accounted for 50% of the total FA obtained. A higher yield (80% molar yield to linoleic acid) was attained with 2.6% (wt/vol) linoleic acid as the substrate in 96 h, resulting in CLA production of 20 mg/mL reaction mixture [consisting of CLA1 (2%) and CLA2 (98%)] and accounting for 80% of total FA obtained. Most of the CLA produced was associated with the cells (ca. 380 mg CLA/g dry cells), mainly as FFA.     

Remarkable reduction of threshold current density of 670 nm GaInAsP/AlGaAs visible lasers by increasing Al content of AlGaAs cladding layers

Extremely low threshold current density operation of the LPE grown 670 nm GaInAsP/AlGaAs lasers has been realised with drastic improvement of the characteristic temperature of the threshold from 45 K to 90 K by increasing the Al content of the AlGaAs cladding layers from 0.7 to 0.95. The threshold current density was 1.7 kA/cm/sup 2/, about one-third of the previously reported value of 5-6 kA/cm/sup 2/.<>