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Objective To investigate the prevalence and characteristics of musculoskeletal pain (MSK) pain in Korean farmers using initial survey data of Farmers' Cohort for Agricultural Work-Related MSK pain (FARM) study. Methods Farmers (534 females and 479 males; mean age 57.2±7.5 years) who owned or rented a farm and belonged to an agricultural cooperative unit were recruited. Presence of pain for each body part (neck, shoulder, arm/elbow, wrist/hand/finger, low back, leg/foot), and characteristics of MSK pain (prevalence, location, duration, severity, and frequency) during the last year was assessed. Additionally, demographic data such as farming duration, history of prior injury, and workload (low, moderate, somewhat hard, or hard) were collected using structured questionnaires. Results Almost all subjects (n=925; 91.3%) complained of pain in more than one body part. The frequency order was low back (63.8%), leg/foot (43.3%), shoulder (42.9%), wrist/hand/finger (26.6%), arm/elbow (25.3%), and neck (21.8%). Low back pain was more frequent in those with over 30 years of farming experience (odds ratio [OR], 1.40; 95% confidence interval, 1.08-1.81). MSK pain was related to history of prior injury (OR, 2.18-5.24; p<0.05) in all body parts except for leg/foot, and very hard workload was associated with low back, leg/foot, neck, shoulder, and wrist/hand/finger pain (OR, 2.88-10.83; p<0.05). Conclusion Most Korean farmers experience MSK pain; furthermore, there is a significant association between pain, history of prior injury, and workload, suggestive of the necessity of coping and preventive strategies to reduce injury or workload. [ABSTRACT FROM AUTHOR]

The watershed scale Soil and Water Assessment Tool (SWAT) model divides watersheds into smaller subwatersheds for simulation of rainfall-runoff and sediment loading at the field level and routing through stream networks. Typically, the SWAT model first needs to be calibrated and validated for accurate estimation through adjustment of sensitive input parameters (i.e., Curve Number values, USLE P, slope and slope-length, and so on). However, in some instances, SWAT-simulated results are greatly affected by the watershed delineation and Digital Elevation Models (DEM) cell size. In this study, the SWAT ArcView GIS Patch II was developed for steep sloping watersheds, and its performance was evaluated for various threshold values and DEM cell size scenarios when delineating subwatersheds using the SWAT model. The SWAT ArcView GIS Patch II was developed using the ArcView GIS Avenue program and Spatial Analyst libraries. The SWAT ArcView GIS Patch II improves upon the SWAT ArcView GIS Patch I because it reflects the topographic factor in calculating the field slope-length of Hydrologic Response Units in the SWAT model. The simulated sediment value for 321 subwatersheds (watershed delineation threshold value of 25 ha) is greater than that for 43 subwatersheds (watershed delineation threshold value of 200 ha) by 201% without applying the SWAT ArcView GIS Patch II. However, when the SWAT ArcView GIS Patch II was applied, the difference in simulated sediment yield decreases for the same scenario (i.e., difference in simulated sediment with 321 subwatersheds and 43 subwatersheds) was 12%. The simulated sediment value for DEM cell size of 50 m is greater than that for DEM cell size of 10 m by 19.8% without the SWAT ArcView GIS Patch II. However, the difference becomes smaller (3.4% difference) between 50 and 10 m with the SWAT ArcView GIS Patch II for the DEM scenarios. As shown in this study, the SWAT ArcView GIS Patch II can reduce differences in simulated sediment values for various watershed delineation and DEM cell size scenarios. Without the SWAT ArcView GIS Patch II, variations in the SWAT-simulated results using various watershed delineation and DEM cell size scenarios could be greater than those from input parameter calibration. Thus, the results obtained in this study show that the SWAT ArcView GIS Patch II should be used when simulating hydrology and sediment yield for steep sloping watersheds (especially if average slope of the subwatershed is >25%) for more accurate simulation of hydrology and sediment using the SWAT model. The SWAT ArcView GIS Patch II is available at for free download. [ABSTRACT FROM AUTHOR]

A 512 Mb diode-switch PRAM has been developed in a 90 nm CMOS technology. The vertical diode-switch using the SEG technology has achieved minimum cell size and disturbance-free core operation. A core configuration, read/write circuit techniques, and a charge-pump system for the diode-switch PRAM are proposed. The 512 Mb PRAM has achieved read throughput of 266 MB/s through the proposed schemes. The write throughput was 0.54 MB/s in internal x2 write mode, and increased to 4.64 MB/s with x16 accelerated write mode at 1.8 V supply. [ABSTRACT FROM AUTHOR]

A 256-Mb phase-change random access memory has been developed, featuring 66-MHz synchronous burst-read operation. Using a charge pump system, write performance was characterized at a low supply voltage of 1.8 V. Measured initial read access time and burst-read access time are 62 and 10 ns, respectively. The write throughput was 0.5 MB/s with internal × 2 write and can be increased to 2.67 MB/s with × 16 write. Endurance and retention characteristics are measured to be 107 cycles and ten years at 99 °C. [ABSTRACT FROM AUTHOR]

The write performance of the 1.8-V 64-Mb phase-change random access memory (PRAM) has been improved, which was developed based on 0.12-μm CMOS technology. For the improvement of RESET and SET distributions, a cell current regulator scheme and multiple step-down pulse generator were employed, respectively. The read access time and SET write time are 68 ns and 180 ns, respectively. [ABSTRACT FROM AUTHOR]

The separation of the base flow component from a varying streamflow hydrograph is called "hydrograph analysis." In this study, two digital filter based separation modules, the BFLOW and Eckhardt filters, were incorporated into the Web based Hydrograph Analysis Tool (WHAT) system. A statistical component was also developed to provide fundamental information for flow frequency analysis and time series analysis. The Web Geographic Information System (GIS) version of the WHAT system accesses and uses U.S. Geological Survey (USGS) daily streamflow data from the USGS web server. The results from the Eckhardt filter method were compared with the results from the BFLOW filter method that was previously validated, since measured base flow data were not available for this study. Following validation, the two digital filter methods in the WHAT system were run for 50 Indiana gaging stations. The Nash-Sutcliffe coefficient values comparing the results of the two digital filter methods were over 0.91 for all 50 gaging stations, suggesting the filtered base flow using the Eckhardt filter method will typically match measured base flow. Manual separation of base flow from streamflow can lead to inconsistency in the results, while the WHAT system provides consistent results in less than a minute. Although base flow separation algorithms in the WHAT system cannot consider reservoir release and snowmelt that can affect stream hydrographs, the Web based WHAT system provides an efficient tool for hydrologic model calibration and validation. The base flow information from the WHAT system can also play an important role for sustainable ground water and surface water exploitation, including irrigation and industrial uses, and estimation of pollutant loading from both base flow and direct runoff. Thus, best management practices can be appropriately applied to reduce and intercept pollutant leaching if base flow contributes significant amounts of pollutants to the stream. This Web GIS based system also demonstrates how remote, distributed resources can be shared through the Internet using Web programming. [ABSTRACT FROM AUTHOR]

A nonvolatile 64-Mb 1T1R phase-transition random access memory (PRAM) has been developed by fully integrating chalcogenied storage material (GST: Ge2Sb2Te5) into 0.18-µm CMOS technology. To optimize SET/RESET distribution, 512-kb sub-array core architecture was proposed, featuring meshed ground line and separated SET/RESET control schemes. Random read access time, random SET and RESET write access times were measured to be 60 ns, 120 ns, and 50 ns, respectively, at 3.0-V supply voltage with 30°C. [ABSTRACT FROM AUTHOR]

We report an improved optical pumping efficiency in a vertical-external-cavity surface-emitting laser (VECSEL) by employing the double-band mirror (DBM), which acts as a pump beam reflector as well as a cavity mirror. The optical pumping efficiency of a VECSEL with the DBM was increased by 23%, as compared to one with the conventional distributed Bragg reflector. It was found that the use of the DBM was more effective in the VECSEL with the shorter absorption layer thickness. [ABSTRACT FROM PUBLISHER]

We report a high-power fundamental transverse mode operation of an optically pumped 920-nm vertical-external- cavity surface-emitting laser. The effects of the gain related structural parameters on the laser performance are investigated. Based on the optimization of the gain structure and the thermal management, a maximum pump-limited output power of 12 W in a TEM00 mode with a slope efficiency of 58% (input power of 24 W) was achieved at room temperature. [ABSTRACT FROM PUBLISHER]

We propose a novel lens-less optical end-pumping scheme and report on the development of a highly efficient and compact green vertical-external-cavity surface-emitting laser (VECSEL). A constant-wave pump-power-limited maximum green output power of 1.1 W and an optical-to-optical conversion efficiency of as high as ~15.7% (=1.1 W/7 W) were achieved using a single chip pump laser diode placed directly behind the VECSEL structure without any beam focusing and shaping optical elements. [ABSTRACT FROM PUBLISHER]

We investigate the effect of relative wavelength difference between material gain and resonance peaks on lasing performance in vertical-external-cavity surface-emitting lasers (VECSELs). We propose a measurement method of the wavelength-dependent modal gain profiles by inserting a birefringent filter inside a cavity in order to modulate the optical loss according to the wavelength. With knowledge of the detailed gain profiles, we achieve a stable green output power of 3.3 W and a power conversion efficiency (= green output power/pump input power) of 17% in VECSEL with a LiB3O5 crystal as an intracavity frequency doubler [ABSTRACT FROM PUBLISHER]

The authors report on the development and demonstration of the high power operation of optically end-pumped vertical external cavity surface emitting laser devices emitting at 532 and 460 nm. 2.7 W green and 1.4 W blue output powers were achieved with a good beam quality by intracavity frequency doubling with second harmonic generation crystal. High efficiency and good beam quality are attributed to the enhanced thermal management by the diamond heat spreader directly bonded to the gain region and effective optical pumping by placing the pump laser diode behind the laser structure. [ABSTRACT FROM AUTHOR]

We report the first demonstration of an end-pumped vertical-external-cavity surface-emitting semiconductor laser (VECSEL) with more than 9.1-W continuous-wave output power at a wavelength of 1079 nm. In order to enable the VECSEL to operate in an end-pumping scheme, a liquid capillary bonding method is used to bond the VECSEL chip to the surface of an optically transparent heat spreader. Moreover, a modified distributed Bragg reflector is applied to the VECSEL chip structure to maximize the pump efficiency. These will result in an end-pumped VECSEL that is characterized by high output power with good beam quality without additional antireflection coatings of the samples. In combination with an end-pumped scheme and desirable output beam, the end-pumped VECSEL will prove useful in a variety of applications requiring compact module and efficient source with high output power [ABSTRACT FROM PUBLISHER]

We present a promising method to achieve a high-performance GaInNAs quantum-well (QW) laser emitting 1.36 μm by metal-organic vapor phase epitaxy. It was found that the insertion of GaNAs-InGaAs layers to GaInNAs QW-GaAs barrier is very effective to control the emission wavelength and improve the optical property of QW. As the thickness of the GaNAs and InGaAs layers was decreased, the wavelength emitted from QW became longer. The optical efficiencies of the proposed QW structure were confirmed by the lasing performance in edge-emitting laser. The threshold current density and slope efficiency per facet of a 1360-nm laser diode are measured to be 892 A/cm2 and 0.135 W/A, respectively. [ABSTRACT FROM PUBLISHER]