“圆”之于设计

＂圆＂既是名词也是动词,作为名词,它代表一种形式,一种内涵,一种品格;作为动词,它又昭示了一种存在方式,一种思维方式,一种精神追求。＂圆＂逐渐从一种单纯的形态上升为一种生命的精神。这种生生不息的生命精神为中国设计的发展提供了无限的动能。     

转炉煤气加压机的选型和配置

介绍了转炉煤气加压机的特性和加压机的选型方法,论述了两种常用的加压机配置模式:全恒频加压机组模式,全变频加压机组模式,评述了这两种模式的优缺点。结合这两种模式的优点,提出了第三种模式:恒频+变频加压机组模式。     

用反极图表示织构

讨论了Harris反极图法所得到的几种结果的评价。比较了两种现有的分析方法和一种新的途径。在最常用的分析中,不同的衍射是等权记录的。第二种方法包括了反射的面积加权,主要考虑了极点分布的不均匀性。在新的方法里,反射是按照它们的多重性因子来加权的。对由一个钢板试样用三种方法所得到的强度比进行了比较。     

铝酸钠溶液种分成核和附聚研究进展

系统总结了铝酸钠溶液种分成核和附聚过程研究进展,铝酸钠溶液种分过程中,成核和附聚过程是影响氢氧化铝产品质量的主要因素之一,众多研究者对成核和附聚过程进行了大量系统的工作。得到了一些普遍性的结论。工业条件下的种分过程晶体生长速率很小,铝酸钠溶液种分成核过程主要为二次成核,依靠附聚过程得到砂状氢氧化铝,研究表明,上述过程都与晶种的表面形貌密切相关,晶种表面性以及各种强化方法对铝酸钠溶液种分的成核和附聚过程的影响仍有待于深入研究。     

种分Δα_k与种分运行方式的关系

对烧结法和拜尔法种分槽的Δαk变化进行了概述,阐述了种分Δαk与种分运行方式的关系。     

铜电解使用钛种板的几个问题

钛种板在铜电解的应用已有十多年历史。但对使用钛种板的有关技术资料却介绍不多。在我国,钛种板在铜电解的应用还因各种原因未得到普遍推广。1975年初,我厂在小型试验的基础上,在五个种板槽中采用了200块钛种板进行了工业试验。在试验过程中,出现了一些小型试验未观察到的现象。     

一段法种分分解制备细白氢氧化铝

依靠提高晶种的活性进行细白氢氧化铝制备,舍弃了硫酸铝两段分解法制备细白氢氧化铝的生产工艺。主要采用一段种分分解工艺制备细白氢氧化铝,分别对活性晶种的制备工艺、晶种种分分解种子比以及分解时间进行了研究,并制备出了细白氢氧化铝,探索出了一种细白氢氧化铝生产新工艺。     

钛种板在大冶冶炼厂的应用

大冶有色金属公司冶炼厂铜电解车间过去一直采用铜种板生产始极片。1990年,该厂进行了铜电解技术改造,开始采用钛种板(约10t)取代铜种板。从此,企业技术经济指标发生了很大变化。与铜种板相比,钛种板优点如下:     

硫化锌精矿加压酸浸新工艺研究

开发了一种低温低压处理硫化锌精矿的新工艺,并对闪锌矿和铁闪锌矿2种锌的主要硫化矿物进行了浸出行为的比较。结果表明,在115℃,500kPa条件下2种矿物锌浸出率均大于97%,硫90%转化成了元素硫,但相同条件下2种矿物浸出液中铁含量具有显著差异。     

冷轧基料山水画缺陷的分析与控制

山水画缺陷是酸轧机组常见的一种表面缺陷。主要介绍了冷轧基料山水画现象的两种表现形态,针对这两种表现形态,分别分析了山水画缺陷的产生原因及预防措施。     

Variability in visual cortex activation during prolonged functional magnetic resonance imaging

OBJECTIVE: To review the EEG features of ring 20 syndrome in two patients and determine the characteristic pattern of this syndrome. The features of our cases and 24 patients reported in the literature will be discussed. SUBJECTS AND METHODS: Report of two patients and review of literature. RESULTS: The two patients had intractable epilepsy since childhood. Their clinical seizures were mostly complex partial seizures. Often the patients seizures were of prolonged duration. Ictal EEG revealed characteristic slow waves, and sharp waves. The slow waves were (1) usually synchronous high-voltage slow waves with or without a spike component predominantly in the frontal and frontopolar areas, (2) sometimes showed a change in frequency every several seconds, (3) continued for a long period, and (4) easily spread diffusely. The sharp waves were 5-6 Hz irregular and diffuse discontinuous sharp waves, and sometimes appeared predominantly in the centroparietal area. The clinical seizure pattern and EEG findings were similar in the 24 published cases. CONCLUSIONS: These EEG findings may be a characteristic feature of ring 20 syndrome and thus may be useful as a diagnostic clue.     

Spectral analysis in cyclic changes of human sleep evaluation

In this study cyclic changes of human sleep structure were examined. For whole-night polysomnograms of 35 healthy volunteers of both sexes, manual hypnograms were created and divided into NREM-REM cycles. EEG signals from C3-A2 derivation were analysed by computer using a Fast Fourier Transform (FFT). For consecutive NREM-REM cycles of individual sleep stages, EEG power density contents for delta, theta, alpha, sigma and beta waves were analysed. For consecutive sleep cycles, a clear decrease in NREM sleep duration, especially slow wave sleep duration, was obtained. In addition, a decrease in power density of delta waves was observed. For consecutive sleep cycles, increases in REM sleep duration and in power density of theta and alpha waves were obtained. In consecutive sleep cycles, high amplitude delta slow waves are replaced by higher frequency and lower amplitude waves. Thus stages of NREM sleep are replaced by stages of REM.     

The effect of high-dose right upper quadrant lithotripsy on normal swine tissue

To assess the effects of high doses of shock waves to organs in the right upper quadrant of the abdomen, 36 adolescent swine were given one treatment of either 2,000 (2k), 6,000 (6k), or 10,000 (10k) shock waves at 24 kV peak pressure using a spark-gap lithotriptor. Shock waves were sonographically focused on the lumen of the gallbladder. Blood and tissue were examined for each group at 48 hours, at 35 days, and at 6 months. This study showed that administration of up to five times the accepted upper limit of shock waves produced no permanent damage. Transient injury, most commonly hematoma, was encountered. No posttreatment intra-abdominal catastrophes occurred. Although no renal injury was seen, it should be noted that the focus of maximum energy was 5 cm cephalad to the right kidney. This study suggests that an increased number of shock waves may be administered safely to this area of the abdomen.     

Small intestinal dysmotility following abdominal irradiation in the rat small intestine

Abdominal symptoms such as diarrhoea, abdominal cramps and vomiting are common during and after abdominal radiotherapy for gynaecological and pelvic malignancy. It has recently been recognized that small intestinal dysmotility may contribute to these symptoms but the underlying mechanisms are unclear in part because of the technical difficulties inherent in performing studies in irradiated small intestine. The aim of the current study was to evaluate small intestinal motor activity using perfused micromanometric techniques in 6-8-cm segments of ileum during arterial perfusion with isotonic oxygenated fluorocarbon solution. Intestinal segments from six rats were studied 4 days after treatment with 10 Gy abdominal irradiation. Ileal segments from nine nonirradiated animals acted as controls. For each experiment the total number of pressure waves, high-amplitude (> 20 mmHg, long-duration > 6 sec) pressure waves, and long (> 20 associated) bursts of pressure waves were determined. Irradiation had no effect on the overall number of pressure waves, but increased high-amplitude long-duration (HALD) pressure waves (248 vs 7, P < 0.01). In control animals HALD waves were localized to a single recording site but after radiotherapy 74% of HALD waves were temporally associated with similar pressure waves in other manometric channels. Forty-seven per cent of associated HALD waves migrated aborally. Retrograde migration of HALD waves was seen in five segments following irradiation. Irradiation abolished bursts of > 20 pressure waves.     

Modeling of Melt Flow and Surface Standing Waves in a Continuous Casting Mold

Majority of surface and subsurface defects in the continuously cast steel may be attributed to surface standing waves and turbulence. A lot of work has been done on surface defects and on understanding the behavior of the surface waves but there is a dearth of literature connecting the two. Also 3‐D modeling of surface waves with heat transfer and solidification has received little attention. In the present study, a 3‐dimensional mathematical model incorporating turbulent fluid flow, heat transfer, and solidification using a commercial code, FLOW3D, was developed. Using the model, the applicability of Froude criterion for scaling down industrial flow systems was analyzed. Although the small scale models, using this criterion, correctly predict the general fluid flow but the prediction of surface waves is not very accurate. Also, the effect of temperature is difficult to incorporate in water models. The model was used to study the effect of temperature on surface waves and verify the water modeling results. The effects of casting and SEN parameters on the fluid flow and surface waves were studied.     

Scleroderma and silicone gel breast prostheses--the Sydney study revisited

Intracellular calcium waves were observed in cultured human myometrium using confocal laser scanning microscopy in the epifluorescence mode. Intracellular calcium waves were observed following stimulation of the cells with 10 mU ml-1 oxytocin in physiological bathing solution, or following substitution of tetraethylammonium chloride for NaCl. Intracellular wave speeds were 18.9 +/- 8.2 microns s-1 in physiological bathing solution. Intracellular calcium waves were also observed in cells bathed in calcium-free solutions, with no significant differences in wave speeds. Calcium waves that crossed cell boundaries were also observed. Some intercellular calcium waves travelled large distances (> 500 microns). Wave speeds for intercellular waves were 7.8 +/- 1.6 microns s-1. Attempts to use octanol to determine the contribution of gap junctions to intercellular calcium wave propagation were unsuccessful because of direct effects of 2 mM octanol on calcium oscillations. These data demonstrate that intra- and intercellular calcium waves are a means of tissue level communication in myometrium that is distinct from action potentials with regard to mechanisms of action, propagation speeds, responses to stimuli, and responses to inhibitors.     

Monitoring Corrosion of Rebar Embedded in Mortar Using High-Frequency Guided Ultrasonic Waves

Corrosion of reinforced concrete structures creates serviceability and safety issues, costing millions of dollars for inspection, repair, and rehabilitation. Recent efforts have focused on monitoring corrosion in situ, providing accurate real-time information for decision-making. The goal of this research is the creation of an embeddable ultrasonic sensing network for assessment of reinforcement deterioration. Toward this effort, guided ultrasonic waves were used to monitor reinforced mortar specimens undergoing accelerated uniform and localized corrosion. Longitudinal waves were invoked at higher frequencies (2–9?MHz), where the attenuation is a local minimum. Using a through-transmission configuration, waveforms were sensitive to both forms of corrosion damage. Scattering, mode conversions, and reflections from irregularities at the bar surface from uniform corrosion and the severely tapered cross section from localized corrosion are thought to cause the increase in attenuation. Because localized corrosion did not yield a discontinuity that was nearly perpendicular to the bar axis, incident waves were severely scattered, mode converted, and rapidly attenuated. As evidence, this was the inability of pulse-echo testing to detect reflected waveforms for localized corrosion.     

热连轧带钢的板形控制

介绍了板形的分类，实际生产中浪形产生的原因，以及单边浪的调整方法和通过控制带钢凸度的方法来消除双边浪和中间浪。     

Downscaling Model Resolution to Illuminate the Internal Wave Field in a Small Stratified Lake

This paper presents the application of hydrostatic and nonhydrostatic three-dimensional hydrodynamic models to a stratified lake. Focus was given to the multiscale response of the internal wave field to strong wind gusts exceeding 20?m?s?1. Simulations were performed using different horizontal grid resolutions with uniform grid sizes varying from 100×100 to 10×10?m. Results of the hydrostatic models were used to investigate the large-scale features of the internal wave motion. With the intent of investigating the high-frequency waves, observed results of these simulations were used as initial conditions for nonhydrostatic simulations using smaller grids. Wavelength of the high frequency waves decreased with grid resolution. However, none of the uniform grids were sufficiently fine to capture the waves of the highest frequency. Simulations performed using a nonuniform grid produced internal waves of similar frequency of the waves observed in the field. The simulations showed that these waves were shear unstable modes and that their vertical and horizontal length scales were in close agreement with results from linear stability analysis.     

A 2.5-dimensional Analytical Model of Cold Leveling for Plates with Transverse Wave Defects

Waves occurring in cold-rolled plates or sheets can be divided into longitudinal and transverse waves. Classical leveling theories merely solve the problem of longitudinal waves, while no well accepted method can be employed for transverse waves. In order to investigate the essential deformation law of leveling for plates with transverse waves, a 2.5-dimensional(2.5-D) analytical approach was proposed. In this model, the plate was transversely divided into some strips with equal width; the strips are considered to be in the state of plane strain and each group of adjacent strips are assumed to be deformation compatible under stress. After calculation, the bending deformation of each strip and the leveling effect of overall plate were obtained by comprehensive consideration of various strips along with the width. Bending of roller is a main approach to eliminate the transverse waves, which is widely accepted by the industry, but the essential effect of bending of roller on the deformation of plates and the calculation of bending of roller are unknown. According to the 2.5-D analytical model, it can be found that, for plates, it is neutral plane offsetting and middle plane elongation or contraction under inner stress that can effectively improve plate shape. Taking double side waves as an example, the appropriate values of bending of roller were obtained by the 2.5-D analytical model related to different initial unevenness, which was applicable to the current on-line adjusting of bending of roller in rolling industry.