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81.
We review the recent progress of electrically injected and optically pumped mid-IR lasers based on antimonide quantum wells with the type II W configuration. W quantum-well diodes have achieved cw operation up to 195 K at lambda = 3.25 mum. Optically pumped devices that employ the diamond pressure bond heat sink have reached 290 K at 3 mum and 210 K at 6 mum. Pulsed power conversion efficiencies of up to 7% at 220 K have been attained by use of an optical pumping injection cavity approach, in which an etalon cavity for the pump beam significantly enhances its absorptance. The angled-grating distributed-feedback configuration has been used to obtain near-diffraction-limited output for an optical pumping stripe width of 50 mum.  相似文献   
82.
The branch information system “Hydrogeology” is part of the environmental information system of the federal state Saxony/Germany. The system comprises the decentral and the central data collection, central data storage and management as well as methods for data processing. As yet, data stocks and software were implemented particularly for point related data including applications for data collection, for the interpretation of pumping tests and grain size analysis as well as visualization. Maps are based on the implemented software applications and database structures. These data are an essential help in decisive processes for administrative objectives with a hydrogeologial and environmental background. Databases and methods for area-related data have been built up and already used for generation of maps.  相似文献   
83.
In present manufacturing environment, the manufacturing flexibility has become one of the strategic competitive tools. Flexibility refers to the availability of alternative resources. These resources may have varied parameters, particularly related to physical and operating system. These physical and operating parameters of alternative resources may influence the system's performance with the changing levels of flexibility and operational control parameters such as scheduling rules. Is increase in a flexibility level provides desired improved performance output? If yes, than under what conditions of physical and operating parameters and under which control strategy (CS)? Is improved performance is present at all increasing levels of flexibility? Flexible manufacturing system (FMS) being consist of numerous physical and operating parameters and complex in nature, the solution to these questions can provide an understanding of the productive levels of flexibility for a given physical and operating parameters of an FMS. This paper establishes the need of modelling of the physical and operating parameters of flexible manufacturing system along with flexibility and presents a simulation study under Taguchi's method analysis of these parameters. The paper contributes an approach to study the impact of variations in physical and operating parameters of an FMS and to identify the level of these variations that do not restrict the advantages of flexibility. The results show that the expected benefits from increasing the levels of flexibility and a superior CS may not be achieved if the physical and operating parameters of alternative machines have variations. Taguchi's method analysis indicates that relative percentage contribution of variations in physical and operating parameters of alternative resources should be negligible or minimum in the performance of FMS. Their increasing relative contribution may restrict the advantages of flexibility. If these variations are higher than increase in flexibility level may be counter productive.  相似文献   
84.
This paper reports an electrostatic microelectromechanical systems (MEMS) gripper with an integrated capacitive force sensor. The sensitivity is more than three orders of magnitude higher than other monolithically fabricated MEMS grippers with force feedback. This force sensing resolution provides feedback in the range of the forces that dominate the micromanipulation process. A MEMS ultrasonic device is described for aligning microobjects suspended in water using ultrasonic fields. The alignment of the particles is of a sufficient accuracy that the microgripper must only return to a fixed position in order to pick up particles less than 100 mum in diameter. The concept is also demonstrated with HeLa cells, thus providing a useful tool in biological research and cell assays  相似文献   
85.
A stream of research exists that explores a country's information technology (IT) industry success. The theoretical model used in these studies is primarily focused on small developed countries. We contend that the factors that contribute to IT industry success in developing countries are likely to differ somewhat from those that play a role in small developed countries. Research to date on IT industry success has neglected developing countries. This study therefore presents an alternative IT industry success model for developing countries. It adapts Ein-dor, Myers, and Raman's (1997) model in developing such a conceptual model. The adapted framework is then applied in a study of IT industry in a developing country—Thailand. We found IT-related foreign direct investment to be vital to IT industry success in Thailand. Unlike findings from earlier studies on small developed countries, geographical location and to a lesser extent government investment promotion policies are also important to IT industry success in a developing country. These findings support the view that there are differences in the factors that affect IT industry success in developed and developing countries. Implications for research and practice are discussed. © 2005 Wiley Periodicals, Inc.  相似文献   
86.
Since 1990, the role of satellite observations for climate and land services increased considerably, especially with the introduction in 2011 of the new generation of NOAA operational satellites, called Suomi NPOSS Polar-Orbiting Partnership (S-NPP). S-NPP will continue as the Joint Polar Satellite System (JPSS) for the next two decades. The Visible Infrared Imaging Radiometer Suite (VIIRS) on the S-NPP spacecraft is accommodating the best technical and scientific features of its predecessors and has several new important features. S-NPP and JPSS, in addition to data collection, will address the impacts of climate and weather on industries, water, energy, population health, and other resources and activities. This article discusses how these operational satellites improve early drought detection, monitoring its features (intensity, duration, area, etc.) and prediction of agricultural losses; how fast the Earth’s natural resources deteriorate; and whether the current warm climate intensifies droughts and increases its area and duration. These climate services have already become available to the global community (http://www.star.nesdis.noaa.gov/smcd/emb/vci/VH/index.php). The S-NPP/VIIRS data permits its users to enhance long-term environmental data records, thereby improving the ability to estimate global warming, land-cover changes, and better monitoring of environmental resources.  相似文献   
87.
ABSTRACT

Two approaches could be utilized to derive the vegetation health indices from recently launched Visible Infrared Imaging Radiometer Suite (VIIRS) sensor with the goal to maintain the consistency with the long-term Advanced Very High Resolution Radiometer (AVHRR) vegetation health products. One approach is to convert VIIRS Normalized Difference Vegetation Index (NDVI)/brightness temperature (BT) to AVHRR, as the first version. The other is to derive long-term pixel-based VIIRS climatology without converting at NDVI/BT level. The second version of products, derived from the new VIIRS pseudo long-term climatology as presented in this article, can trace the signature of the long-term AVHRR vegetation health products quite well, in terms of histogram, correlation coefficients, time series, and so on. The extended products with higher resolutions also perform as expected, indicating that the constructed long-term high-resolution climatology is reasonable. The third version of the products, based on VIIRS real long-term climatology, still needs many years to develop.  相似文献   
88.
The zebrafish pineal gland plays a fundamental role in the regulation of the circadian rhythm through the melatonin secretion. The pinealocytes, also called photoreceptive cells, are considered the morphofunctional unit of pineal gland. In literature, the anatomical features, the cellular characteristics, and the pinealocytes morphology of zebrafish pineal gland have not been previously described in detail. Therefore, this study was undertaken to analyze the structure and ultrastructure, as well as the immunohistochemical profile of the zebrafish pineal gland with particular reference to the pinealocytes. Here, we demonstrated, using RT-PCR, immunohistochemistry and transmission electron microscopy, the expression of the mRNA for rhodopsin in the pineal gland of zebrafish, as well as its cellular localization exclusively in the pinealocytes of adult zebrafish. Moreover, the ultrastructural observations demonstrated that the pinealocytes were constituted by an outer segment with numerous lamellar membranes, an inner segment with many mitochondria, and a basal pole with the synapses. Our results taken together demonstrated a central role of zebrafish pinealocytes in the control of pineal gland functions.  相似文献   
89.
Translocations at chromosomal band 11q23 characterize most de novo acute lymphoblastic leukemias (ALL) of infants, acute myeloid leukemias (AML) of infants and young children, and secondary AMLs following epipodophyllotoxin exposure. The chromosomal breakpoints at 11q23 have been cloned from isolated cases of de novo ALL and AML. Using an 859-base pair BamHI fragment of human ALL-1 complementary DNA that recognizes the genomic breakpoint region for de novo ALL and AML, we investigated two cases of secondary AML that followed etoposide-treated primary B-lineage ALL. In the first case, the translocation occurred between chromosomes 9 and 11 and the breakpoint at 11q23 localized to the same 9-kilobase region of the ALL-1 gene that is disrupted in most of the de novo leukemias. In the second case the translocation was between chromosomes 11 and 19. The breakpoint occurred outside of the ALL-1 breakpoint cluster region.  相似文献   
90.
The step away from a synchronized or cue-based brain-computer interface (BCI) and from laboratory conditions towards real world applications is very important and crucial in BCI research. This work shows that ten naive subjects can be trained in a synchronous paradigm within three sessions to navigate freely through a virtual apartment, whereby at every junction the subjects could decide by their own, how they wanted to explore the virtual environment (VE). This virtual apartment was designed similar to a real world application, with a goal-oriented task, a high mental workload, and a variable decision period for the subject. All subjects were able to perform long and stable motor imagery over a minimum time of 2 s. Using only three electroencephalogram (EEG) channels to analyze these imaginations, we were able to convert them into navigation commands. Additionally, it could be demonstrated that motivation is a very crucial factor in BCI research; motivated subjects perform much better than unmotivated ones.  相似文献   
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