石南21井区头屯河组油藏注采井网调整先导试验

石南21井区头屯河组油藏受构造、沉积微相、流体分布、注采井网和注采强度等因素的影响,不同区域开发效果差异较大,局部区域生产恶化。开展注采结构调整研究表明,对于油藏储量丰度低的区域调整为排式注采井网可取得较好的开发效果,采收率从39.2%提高至42.9%;而油藏丰度高的区域则采用加密调整的方式可取得较好开发效果,采收率从37.2%提高至43.6%.     

Photo‐Stable Organic Thin‐Film Transistor Utilizing a New Indolocarbazole Derivative for Image Pixel and Logic Applications

Small molecule pentacene layer has been a representative among many organic thin‐film transistor (OTFT) channels with decent p‐type mobilities, but it is certainly light‐sensitive due to its relatively small highest occupied molecular orbital‐lowest unoccupied molecular orbital (HOMO‐LUMO) gap (1.85 eV). Although a few other small molecule‐based layers have been reported later, their photo‐stabilities or related device applications have hardly been addressed. Here, a new photostable organic layer is reported, heptazole (C₂₆H₁₆N₂), which has almost the same HOMO level as that of pentacene but with a higher HOMO‐LUMO gap (≈2.95 eV). This heptazole OTFT displays a decent mobility comparable to that of conventional amorphous Si TFTs, showing good photostability unlike pentacene OTFTs. An image pixel driving the photostable heptazole OTFT connected to a pentacene/Al Schottky photodiode is demonstrated. This heptazole OTFT also conveniently forms a logic inverter coupled with a pentacene OTFT, sharing Au for source/drain.     

Development of the composite bumper beam for passenger cars

The fuel efficiency and emission gas regulation of passenger cars are two important issues in these days. The best way to increase the fuel efficiency without sacrificing safety is to employ fibre reinforced composite materials in the body of cars.

In this work, a new composite bumper that has two pads at the ends of the bumper was developed. The two pads were designed to hit the front two tyres of the car when the bumper brackets collapsed during collision. The end of the bumper beam was designed to have a tapered section to absorb energy by progressive buckling when the pads hit the rims of wheels after collapsing tyres.

The composite bumper beam was made of glass fibre fabric epoxy composite material except the elbow section. The elbow section was made of carbon fibre epoxy composite material to increase bending stiffness. From the static bending test of the prototype composite bumper, it was found that the weight of the composite bumper beam was only 30% that of the steel bumper beam without sacrificing the static bending strength.     

Surface modification of silicon by laser surface treatment: Improvement of adhesion and copper deposition

We have studied the use of lasers for modifying the surface properties of silicon to improve its wettability and adhesion characteristics. Using a 4th harmonic Nd:YAG (λ = 266 nm, pulse) laser, the wettability and adhesion characteristics of the silicon surfaces have been enhanced by laser irradiation. It was found that laser surface treatment of silicon modified the surface energy. By the contact angle measurement, using distilled water, the wetting characteristics of silicon after the laser irradiation show a decrease in the contact angle and a change in the surface chemical composition. In the case of the laser-treated silicon surface, laser direct writing of copper lines has been achieved through pyrolytic decomposition of copper formate by using a focused Ar⁺ laser beam (λ = 514.5 nm, continuous wave (CW)) on the silicon substrates. The deposited lines and surface chemical compositions were measured by energy dispersive x-ray (EDX), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and surface profiler (Alpha Step 500, San Jose, CA) to examine the cross section of deposited copper lines.     

Evaluation of a pellet-clad mechanical interaction in mixed oxide fuels during power transients by using axisymmetric finite element modeling

MOX fuel rod behavior due to PCMI during power transients was evaluated using a finite element code, ABAQUS. Clad elongation is calculated through a coupled temperature–displacement analysis where a half-pellet is axisymmetrically modeled. Parametric study for the PCMI model is preliminary performed to identify the dominant factors and examine the applicable range of the model. The comparison of the predicted results with recent MOX in-pile data shows that the centerline temperature and clad elongation are evaluated within an acceptable range.     

Propagation measurements for fixed wireless loops (FWL) in asuburban region with foliage and terrain blockages

We present the results of propagation measurements at 2.485 GHz for fixed wireless loops. Path loss measurements were performed and characterized at 43 subscriber locations around a base station antenna located on top of Crawford Hill in Holmdel, NJ. This suburban location is characterized by rolling hills, foliage, and terrain blockages. Temporal and horizontal motion path loss fluctuations were found to be uncorrelated, each characterized by a different Ricean distribution. Lower r.m.s. delay spreads were obtained with directive subscriber antennas than with omni-directional antennas. No substantial gain loss (less than 2 dB) of subscribers' directive antennas was observed. The effects of trees, with foliage, surrounding the base station upon the path loss and the ratio of scattered power to specular power are also examined. The distance exponent of path loss versus distance (about 1.5) was observed to be less than free-space. Diffraction loss from hilltop trees, shadowing the base station, are suspected to be the cause. This loss decreases as the remote moves further away and comes out of the shadow. Scattered power from directions other than line-of-sight was observed to be as high as one half of the specular contribution when tree scattering near the base station was significant     

Remeshing for metal forming simulations—Part I: Two‐dimensional quadrilateral remeshing

In this paper, a general framework of practical two‐dimensional quadrilateral remeshing, which includes the determination of remeshing time, automatic quadrilateral mesh generation, and data transfer process, will be formulated. In particular, the current work contains new algorithms of mesh density specification according to the distribution of effective strain‐rate gradients, mesh density smoothing by fast Fourier transform (FFT) and low‐pass filtering techniques, coarsening it by node placement scheme, and a modified Laplacian mesh smoothing technique. The efficiency of the developed remeshing scheme was tested through three practical two‐dimensional metal forming simulations. The results clearly indicate that the algorithms proposed in this study make it possible to simulate two‐dimensional metal forming problems efficiently and automatically. Copyright © 2002 John Wiley & Sons, Ltd.     

Thoracic actinomycosis: CT findings

PURPOSE: To characterize computed tomographic (CT) findings of thoracic actinomycosis. MATERIALS AND METHODS: Chest CT scans and radiographs obtained in 22 patients with histopathologically proved thoracic actinomycosis were retrospectively reviewed. All patients were immunocompetent; they were aged 12-73 years (mean, 42.6 years; 14 male, eight female). CT findings were correlated with histopathologic findings in nine patients who underwent surgery (lobectomy [n = 8] or segmental resection [n = 1]). RESULTS: All of the lesions were unilateral, with an average diameter of 6.5 cm (range, 2-12 cm). Patchy air-space consolidation (n = 20) or a mass (n = 2) was seen on CT scans. Fifteen (75%) of the 20 patients with air-space consolidation had central areas of low attenuation (5-30 mm in diameter) within the consolidation. Thirteen of the 15 patients underwent contrast medium-enhanced CT. Ten (77%) of the 13 patients showed ring-like rim enhancement. Adjacent pleural thickening was seen in 16 patients (73%). At histopathologic examination, central low-attenuation areas at CT were seen as microabscesses with sulfur granules or a dilated bronchus that contained inflammatory cells and Actinomyces colonies. Peripheral enhancement of the low-attenuation areas was wall of the microabscess or surrounding parenchyma composed of granulation tissue rich in vascularity. CONCLUSION: Findings of chronic segmental air-space consolidation that contained low-attenuation areas with peripheral enhancement or adjacent pleural thickening at CT were suggestive of thoracic actinomycosis.     

Impact of national culture on information technology usage behaviour: an exploratory study of decision making in Korea and the USA

The globalization of world markets has led to the introduction of information technology, most often developed in western cultures, to other societies. Cultural values were embedded in the design and use of these technologies. Often, the receiving society did not embrace the technology because of culture. Examples of such behaviour include executive information systems and group decision support systems, which are cited later. This study examines the use of non-specific applications of information technology for organizational decision making. A survey instrument was developed to measure decision makers' perceptions of the impact of information technology on the decision process. Decision makers in Korea and the USA indicated their perceptions of the extent information technology use impacted their decision making activities. The results indicated some behaviours appeared to change to take advantage of the technology, while others, particularly those associated with the cultural preference for communication, did not.