TRT顶压控制系统及其安全性的研究与优化

介绍了天钢1~#TRT顶压控制系统,对现有的顶压控制系统进行了分析,在原有差压调节模式的基础上增加了顶压调节模式,将实际操作改为差压调节与顶压调节两种互选模式,提高了系统的发电效率;对旁通阀组的控制进行了优化,优化后极大地提高了系统的安全性,保证了炉顶压力的稳定,延长了设备的使用寿命,产生了较高的经济效益。     

提高转炉护炉效果的实践

从转炉耐材的损害机理入手,分析了耐材的损耗机理,探讨了炉渣的优化机制,对炉渣的组成及渣料的使用进行优化,对溅渣的工艺进行了改进,实现了转炉护炉的提升,延长了转炉的使用寿命,降低了耐材的损耗,降低了转炉工序的成本。     

废水处理站自动控制系统的应用

介绍了邯钢冷轧废水站的配套项目废水处理站的自动控制系统,主要从自控设备组成、网络控制系统等方面论述了控制功能的实现,该系统的应用为ERP的数据采集提供了很好的保证,提高了电气控制的集成度和可靠性,简化了控制环节,提高了生产效率.     

浅议矿脉变化规律与探矿方法

概要介绍了樟东坑矿区的主要地质特征,在前人工作的基础上,对矿床的基本特征(尤其是矿脉的变化特征)进行了分析、探讨和总结;利用这些特性及其变化规律,采用一些新的探矿方法不但找到了一些隐伏盲矿,增加了地质储量,延长了矿山的服务年限,而且降低了探矿费用,减少了采矿的盲目性,节约了成本,增加了经济效益。     

采用Boost技术优化企业数据备份保护架构

为了解决大型制造企业数据中心架构变更后,在数据保护方面所面临的多种难题,对适用的数据保护技术进行了研究探讨.最终实现了企业数据保护平台架构的转型升级,提升了平台自身的安全性,改善了备份数据的传输架构,备份效率提升了10倍以上.实现了备份任务的集中智能管理,节约了备份窗口,实现了备份资源的一次性分配与自动回收,释放了备份...     

轧钢加热炉改造

针对轧钢加热炉加热能力不足,炉墙冒火,自动化控制水平落后的情况,对加热炉进行了改造,延长了加热炉的长度,更换了单蓄热式空气烧嘴,并对自动控制系统进行了升级改造,从而消除了炉墙冒火的现象,提高了加热能力和自动控制水平,降低了煤气消耗,取得了良好的经济效益。     

ACS6000SD变频器在粗轧机主传动系统中的应用

济钢中厚板厂3500线粗轧机改造主传动系统采用ACS6000SD变频驱动系统,系统的整流侧和逆变侧采用了对称结构,降低了维护难度;采用了IGCT技术,保证了系统的性能响应;使用了DTC技术,提高了系统的鲁棒性。这种交直交系统做到了对电网的最少谐波运行,既减少了对电网的污染,又省去了无功补偿系统的投资。     

工业机器人在鞍钢型钢生产线的设计与应用

根据鞍钢股份有限公司型钢生产线工艺实际,制定了机器人硬件设计方案和机器人软件实现方案,实现了工业机器人自动贴标喷码技术在型钢生产线的应用.该系统的应用满足了产线工艺要求,提升了产线生产效率,提高了产品标识的准确性和可追溯性,贴标准确率和喷码准确率均达到了99％,实现了危险岗位无人作业,作业周期缩短了25％;同时,实现了产品标识的统一规范性,提升了企业产品形象.     

45 t转炉修炉车液压传动系统设计

介绍了砌炉车的工作原理,围绕其工作原理和使用实践,对其液压系统进行了重新设计,选用了二通流量控制阀,实现了对修炉车三条油缸流量的均衡分配,确保了三个油缸的同步动作,有效地解决了原设计采用的比例分配阀流量分配不均的问题,提高了设备运行的平稳性和可靠性.     

空压机积炭的原因及改进措施

本文分析了影响空压机积炭堆积过快的原因,介绍了生产工艺中存在的问题及改进措施,改进后减少了空压机积炭堆积的速度,延长了空压机部件使用寿命,降低了维修成本,提高了空压机利用率和运行效率,达到节能降耗的目的。     

Kinetics of oxygen uptake at the onset of exercise in boys and men

The objective of this study was to compare the O2 uptake (VO2) kinetics at the onset of heavy exercise in boys and men. Nine boys, aged 9-12 yr, and 8 men, aged 19-27 yr, performed a continuous incremental cycling task to determine peak VO2 (VO2 peak). On 2 other days, subjects performed each day four cycling tasks at 80 rpm, each consisting of 2 min of unloaded cycling followed twice by cycling at 50% VO2 peak for 3.5 min, once by cycling at 100% VO2 peak for 2 min, and once by cycling at 130% VO2 peak for 75 s. O2 deficit was not significantly different between boys and men (respectively, 50% VO2 peak task: 6.6 +/- 11.1 vs. 5.5 +/- 7.3 ml . min-1 . kg-1; 100% VO2 peak task: 28.5 +/- 8.1 vs. 31.8 +/- 6.3 ml . min-1 . kg-1; and 130% VO2 peak task: 30.1 +/- 5.7 vs. 35.8 +/- 5.3 ml . min-1 . kg-1). To assess the kinetics, phase I was excluded from analysis. Phase II VO2 kinetics could be described in all cases by a monoexponential function. ANOVA revealed no differences in time constants between boys and men (respectively, 50% VO2 peak task: 22. 8 +/- 5.1 vs. 26.4 +/- 4.1 s; 100% VO2 peak task: 28.0 +/- 6.0 vs. 28.1 +/- 4.4 s; and 130% VO2 peak task: 19.8 +/- 4.1 vs. 20.7 +/- 5. 7 s). In conclusion, O2 deficit and fast-component VO2 on-transients are similar in boys and men, even at high exercise intensities, which is in contrast to the findings of other studies employing simpler methods of analysis. The previous interpretation that children rely less on nonoxidative energy pathways at the onset of heavy exercise is not supported by our findings.     

BNb与BNbRE钢轨踏面区的内耗

测量了BNb钢和BNbRE钢重轨踏面区使用(热轧)态及其700℃、30min WC、室温变形态试样的内耗。发现,两种钢轨热轧态试样都有Snoek—Kê—Kster(SKK)峰;但这两种钢热轧态样品的内耗,有较明显的差异:未加稀土的BNb钢轨的SKK峰明显地大于加丁稀土的BNbRE钢轨的峰,前者的峰温度也较后者高约20℃;但后者有可测的Snoek峰,而前者则没有此峰。两种钢变形态样品的SKK峰大致相同。对结果做了讨论。     

Analysis of impaired exercise capacity in patients with cirrhosis

Exercise limitation in cirrhosis is typically attributed to a cirrhotic myopathy (without impaired oxygen utilization) and/or a cardiac chronotropic dysfunction. We performed symptom-limited cardiopulmonary exercise testing in 19 cirrhotics without confounding variables (cardiopulmonary disease, beta blockade, anemia, smoking). Twelve concurrently exercised patients without cirrhosis and with normal resting pulmonary function were controls. Oxygen consumption (VO2) at peak exercise, at anaerobic threshold (VO2-AT), work rate (WR), and heart rate (HR) were measured. Cirrhotics had significantly lower peak WR (73+/-4 vs 107+/-7% predicted, p < 0.001), VO2 (72+/-4 vs 98+/-5% predicted, P < 0.001), VO2-AT (53+/-4 vs 71+/-5% predicted peak VO2, P < 0.01), HR (83+/-2 vs 91+/-2% predicted, P < 0.01) and were more likely to have chronotropic dysfunction (peak HR < 85% predicted). Six cirrhotics had normal aerobic capacity (peak VO2 > 80% predicted), while 13 were abnormal. The abnormals had an earlier AT (46+/-2 vs 67+/-3% predicted peak VO2, P < 0.05) but no difference in peak HR percent predicted was found. In conclusion, two thirds of cirrhotics, without confounding factors, have significantly reduced aerobic capacity. Cirrhotic myopathy (without impaired O2 utilization) and cardiac chronotropic dysfunction do not adequately account for the observed decrease in aerobic capacity.     

Effect of acute pharmacological reduction of plasma free fatty acids on growth hormone (GH) releasing hormone-induced GH secretion in obese adults with and without hypopituitarism

In obesity, there is a markedly decreased GH secretion. The diagnosis of GH deficiency (GHD) in adults is based on peak GH responses to stimulation tests. In the severely obese, peak GH levels after pharmacological stimulation are often in the range that is observed in hypopituitary patients. To distinguish obese subjects from GHD patients, it will be necessary to demonstrate that reduced GH responsiveness to a given test is reversible in the former, but not in the latter, group. Recent studies have shown that reduction of plasma free fatty acids (FFA) with acipimox in obese patients restores their somatotrope responsiveness. There are no data evaluating GH responsiveness to acipimox plus GHRH in obese adults with hypopituitarism. The aim of the present study was to evaluate the effect of acute pharmacological reduction of plasma FFA on GHRH-mediated GH secretion in obese normal subjects and obese adults with hypopituitarism. Eight obese patients with a body mass index of 34.2+/-1.2; eight obese adults with hypopituitarism, with a body mass index of 35.5+/-1.9; and six control subjects were studied. All the patients showed an impaired response to an insulin-tolerance test (0.15 U/kg, i.v.), with a peak GH secretion of less than 3 microg/L. Two tests were carried out. On one day, they were given GHRH (100 microg, i.v., 0 min), preceded by placebo; and blood samples were taken every 15 min for 60 min. On the second day, they were given GHRH (100 microg, i.v., 0 min), preceded by acipimox (250 mg, orally, at -270 min and -60 min); and blood samples were taken every 15 min for 60 min. The administration of acipimox induced a FFA reduction during the entire test. Normal control subjects had a mean peak (microg/L) of 23.8+/-4.8 after GHRH-induced GH secretion; previous acipimox administration increased GHRH-induced GH secretion, with a mean peak of 54.7+/-14.5. In obese patients, GHRH-induced GH secretion was markedly reduced, with a mean peak (microg/L) of 3.9+/-1; previous administration of acipimox markedly increased GHRH-mediated GH secretion, with a mean peak of 16.0+/-3.2 (P < 0.05). In obese adults with hypopituitarism, GHRH-induced GH secretion was markedly reduced, with a mean peak (microg/L) of 2+/-0.7; previous acipimox administration did not significantly modify GHRH-mediated GH secretion, with a mean peak of 3.3+/-1.1 (P < 0.05). The GH response of obese patients and obese adults with hypopituitarism was similar after GHRH alone. In contrast, the GH response after GHRH plus acipimox, was markedly decreased in obese adults with hypopituitarism (mean peak, 3.3+/-1.1), compared with obese patients (mean peak, 16.0+/-3.2) (P < 0.05) and control subjects (mean peak, 54.7+/-14.5) (P < 0.01). In conclusion, GH secretion, after GHRH-plus-acipimox administration, is reduced in obese adults with hypopituitarism patients, when compared with obese normal patients. Testing with GHRH plus acipimox is safe and is free from side effects and could be used for the diagnosis of GHD in adults.     

氧化石墨烯的光学性能研究

本文主要研究了浓度和激发波长对单层氧化石墨烯水分散液光学性能的影响,结果表明：较高浓度的样品在360～500 nm之间有一个宽泛的吸收峰,360 nm处有尖锐的吸收峰。低浓度的样品在230和300 nm处有吸收峰。在365 nm波长的激发下,随着浓度的降低,发射峰位置由560～600 nm变成了蓝光发射。0.4 mg/ml的样品的发射峰位置受激发波长影响不大,但发射强度变化明显,且发射峰很宽泛。浓度为0.02 mg/ml的样品发射峰位置强烈依赖于激发波波长,利用这个性能,氧化石墨烯在可调谐光电领域会有很大应用潜力。     

Effect of exercise intensity on glucose and insulin metabolism in obese individuals and obese NIDDM patients

OBJECTIVE: The primary purpose of this study was to evaluate the acute effect of exercise of differing intensity on plasma glucose and insulin responses to an oral glucose challenge. RESEARCH DESIGN AND METHODS: Six obese men and six obese men with NIDDM of similar age, weight, percentage body fat, and VO2peak participated in the study. Each subject underwent two 7-day exercise programs in a counterbalanced order at 2-week intervals. During each 7-day exercise period, the subjects cycled every day at a power output corresponding to 50% VO2peak for 70 min or 70% VO2peak for 50 min. Muscle glycogen utilization was estimated during exercise on day 7 using a [3H]glucose infusion technique in conjunction with indirect calorimetry. During the day before and after each 7-day exercise period, a 3-h oral glucose tolerance test (OGTT) was administered after a 12-h overnight fast. RESULTS: The average caloric expenditure did not differ between exercise at 50 and 70% VO2peak in both obese and obese NIDDM subjects. However, the carbohydrate oxidation was higher (P < 0.05) during exercise at 70 than 50% VO2peak in obese subjects (77 +/- 5 vs. 68 +/- 6 g) and obese NIDDM subjects (70 +/- 4 vs. 58 +/- 6 g). Muscle glycogen utilization was also higher (P < 0.05) during exercise at 70 than 50% VO2peak in obese subjects (59 +/- 9 vs. 30 +/- 7 g) and in obese NIDDM subjects (48 +/- 5 vs. 24 +/- 5 g). In obese subjects, plasma glucose response area during the OGTT did not change after 7 days of exercise at either 50 or 70% VO2peak. Plasma insulin response area during the OGTT also did not change after 7 days of exercise at 50% VO2peak. However, plasma insulin response area was reduced (P < 0.05) after 7 days of exercise at 70% VO2peak (9,644 +/- 1,783 vs 7,538 +/- 1,522 microU.ml-1.180 min-1). In obese NIDDM subjects, both plasma glucose and insulin response areas during the OGTT did not decrease after 7 days of exercise at either 50 or 70% VO2peak. CONCLUSIONS: It is concluded that the exercise-induced improvement in insulin sensitivity is influenced by exercise intensity in obese individuals. The improved insulin sensitivity after 7 days of exercise at 70% VO2peak in obese individuals may be related to greater muscle glycogen utilization during exercise. The lack of improvement in glucose tolerance and insulin sensitivity after 7 days of exercise at either 50 or 70% VO2peak in obese NIDDM patients may be due to the fact that the NIDDM patients selected in the present study were relatively hypoinsulinemic.     

Post-exercise changes in blood pressure, heart rate and rate pressure product at different exercise intensities in normotensive humans

To evaluate the effect of exercise intensity on post-exercise cardiovascular responses, 12 young normotensive subjects performed in a randomized order three cycle ergometer exercise bouts of 45 min at 30, 50 and 80% of VO2peak, and 12 subjects rested for 45 min in a non-exercise control trial. Blood pressure (BP) and heart rate (HR) were measured for 20 min prior to exercise (baseline) and at intervals of 5 to 30 (R5-30), 35 to 60 (R35-60) and 65 to 90 (R65-90) min after exercise. Systolic, mean, and diastolic BP after exercise were significantly lower than baseline, and there was no difference between the three exercise intensities. After exercise at 30% of VO2peak, HR was significantly decreased at R35-60 and R65-90. In contrast, after exercise at 50 and 80% of VO2peak, HR was significantly increased at R5-30 and R35-60, respectively. Exercise at 30% of VO2peak significantly decreased rate pressure (RP) product (RP = HR x systolic BP) during the entire recovery period (baseline = 7930 +/- 314 vs R5-30 = 7150 +/- 326, R35-60 = 6794 +/- 349, and R65-90 = 6628 +/- 311, P < 0.05), while exercise at 50% of VO2peak caused no change, and exercise at 80% of VO2peak produced a significant increase at R5-30 (7468 +/- 267 vs 9818 +/- 366, P < 0.05) and no change at R35-60 or R65-90. Cardiovascular responses were not altered during the control trial. In conclusion, varying exercise intensity from 30 to 80% of VO2peak in young normotensive humans did not influence the magnitude of post-exercise hypotension. However, in contrast to exercise at 50 and 80% of VO2peak, exercise at 30% of VO2peak decreased post-exercise HR and RP.     

Serum levels of cardiac troponin I and troponin T in estimating myocardial infarct size soon after reperfusion

BACKGROUND: Cardiac troponin I (TnI) and troponin T (TnT) are highly specific myocardial markers. OBJECTIVE: To determine whether their serum levels can be used to estimate myocardial infarct size soon after reperfusion. METHODS: We measured the serum levels of TnI, TnT, and creatine kinase every 3 h, and the serum cardiac myosin light chain I (MLCI) every 24 h, in 42 patients with acute myocardial infarction in whom reperfusion therapy had successfully been performed. We calculated the severity of regional hypokinesis by analyzing the follow-up ventriculograms with the centerline method. RESULTS: The time from reperfusion to the peak level for TnI was 6.1 +/- 3.5 h, significantly shorter than those for creatine kinase (7.5 +/- 4.1 h) and MLCI (55 +/- 28 h). The time to peak level for TnT (6.8 +/- 4.0 h) differed significantly from that for MLCI but not from that for creatine kinase. There was a significant correlation between the peak levels of TnI and TnT (r = 0.86). The peak TnI and TnT levels were correlated well to the peak creatine kinase level (r = 0.67 and 0.69, respectively), total creatine kinase release (r = 0.66 and 0.66), and the peak MLCI level (r = 0.71 and 0.80). We observed excellent correlations between the peak levels of TnI and TnT, and regional hypokinesis (r = -0.84 and -0.85, respectively). These were comparable to the correlations between regional hypokinesis and the peak creatine kinase level (r = 0.75), total creatine kinase release (r = -0.72), and the peak MLCI level (r = -0.76). CONCLUSIONS: These results suggest that the peak serum levels of TnI and TnT in patients with successful reperfusion are accurate and early indices of infarct size.     

Peak oxygen deficit predicts sprint and middle-distance track performance

The purpose of this study was to determine the value of the peak oxygen deficit (POD) as a predictor of sprint and middle-distance track performance. POD, peak blood lactate, VO2peak, lactate threshold, and running economy at 3.6 m.s-1 were measured during horizontal treadmill running in 22 male and 19 female competitive runners of different event specialties. Subjects also completed running performance trials at 100, 200, 400, 800, 1500, and 5000 m. Correlations of track performances with POD (ml.kg-1) (-0.66, -0.71, -0.71, -0.62, -0.52, and -0.40) were moderately strong at the sprint and middle distances, accounting for 44-50% of the performance variance at the three shortest distances. Correlations of track performances with peak blood lactate concentration were lower than with POD and accounted for approximately one-half as much of the performance variance (21-26%) at the three shortest distances. Multiple regression analyses indicated that the POD was the strongest metabolic predictor of 100-, 200- and 400-m performance, and that VO2peak was the strongest metabolic predictor of 800-, 1500-, and 5000-m performance. We conclude that the POD is a moderately strong predictor of sprint and middle-distance track performance.     

Age alters regional distribution of blood flow during moderate-intensity exercise

During dynamic exercise in warm environments, requisite increases in skin and active muscle blood flows are supported by increasing cardiac output (Qc) and redistributing flow away from splanchnic and renal circulations. To examine the effect of age on these responses, six young (Y; 26 +/- 2 yr) and six older (O; 64 +/- 2 yr) men performed upright cycle exercise at 35 and 60% of peak O2 consumption (VO2peak) in 22 and 36 degrees C environments. To further isolate age, the two age groups were closely matched for VO2peak, weight, surface area, and body composition. Measurements included heart rate, Qc (CO2 rebreathing), skin blood flow (from increases in forearm blood flow (venous occlusion plethysmography), splanchnic blood flow (indocyanine green dilution), renal blood flow (p-amino-hippurate clearance), and plasma norepinephrine concentration. There were no significant age differences in Qc; however, in both environments the O group maintained Qc at a higher stroke volume and lower heart rate. At 60% VO2peak, forearm blood flow was significantly lower in the O subjects in each environment. Splanchnic blood flow fell (by 12-14% in both groups) at the lower intensity, then decreased to a greater extent at 60% VO2peak in Y than in O subjects (e.g., -45 +/- 2 vs. -33 +/- 3% for the hot environment, P < 0.01). Renal blood flow was lower at rest in the O group, remained relatively constant at 35% VO2peak, then decreased by 20-25% in both groups at 60% VO2peak. At 60% VO2peak, 27 and 37% more total blood flow was redistributed away from these two circulations in the Y than in the O group at 22 and 36 degrees, respectively. It was concluded that the greater increase in skin blood flow in Y subjects is partially supported by a greater redistribution of blood flow away from splanchnic and renal vascular beds.