提高电炉炼钢效率的新技术

比利时的古斯塔布勒公司最近投产了一台出钢量为８５／１１５ｔ、变压器容量为９５ＭＶＡ的直流电弧炉，其出钢一出钢时间低于６０ｍｉｎ。与传统的三相交流电弧炉相比较，电能消耗减少约５％。吨钢电极耗量降低到１．４ｋｇ以下。     

电炉炼钢效率的改进

比利时的Ｇｕｓｔａｖｅ Ｂｏｅｌ厂的一台直流电弧炉最近投入使用，其出钢量为８５／１１５吨。变压器额定功率是９５ＭＶＡ，出钢到出钢时间小于６０分钟，与传统三相交流电炉相比，电能消耗显著降低约５％，电极消耗低于１．４ｋｇ／ｔ。     

转炉内加锰铁脱硫工艺的研究和实践

阐述了在转炉内加锰铁脱硫的理论和可行性，以及九钢炼钢厂的实践，其脱硫效率能达到40％～60％。     

英钢公司采用氧气碱性转炉炼钢法生产低磷钢的实践

英国钢公司对型材，板材及带材产品，在保证其价格具有竞争的前提下，优先的原则是将钢中的磷含量减少到〈０．０１％，为此，英钢公司已使用了硅铝酸盐熔剂，并采用了一些相应的炼钢工艺技术，使未经过预处理的铁水，冶炼后达到硅含量为０．４％或〈０．４％，磷含量为０．０７％～０．０９％的低磷规格，同时提高了成本效果。开始试验期间，在吹炼和出钢过程中，８５％和１００％地监控了钢，渣的化学过程。这表明，大部分渣的生成     

10t电炉炉衬扩容改造实践

本文叙述了广钢第二电炉炼钢分厂１０ｔ电炉扩容改造的过程。１０ｔ电炉通过扩容改造，平均每炉出钢量提高１８．７１％，电炉日历利用系数提高２４．６１％，平均炉龄提高８．３６％。     

为生产纯净钢开发的白渣高效脱硫工艺

１前言沙伦钢公司有两座１２５ｔ交流电弧炉。最初的产品大纲是铝脱氧低碳和中碳钢锭。在最初６个月的生产期间，最终硫含量在０．０１％～０．０２５％之间。为了提高钢的质量，开发了一种“白渣”工艺。其目的是降低出钢期间渣中的ＦｅＯ＋ＭｎＯ。提高渣的流动性，以达...     

转炉工艺因素对08Al钢锰回收率的影响

采用数理统计方法，研究分析了转炉炼钢工艺因素对80Al钢脱氧合金化过程中Mn元素回收率的影响。结果表明，在现行生产工艺条件下，提高终点碳含量，降低出钢温度、渣中(％FeO)含量和出钢下渣量，合理控制出钢流钢时间，有利于提高Mn元素的回收率。     

北方重工50t EBT超高功率电弧炉无富氧泡沫渣工艺

北方重工业集团50t偏心炉底出钢超高功率电弧炉冶炼周期为2h，采用氧化铁皮作为氧化剂，炉料中配入20％以上生铁，控制炉渣碱度2～3．5，渣中FeO含量为15％～25％，渣量3．0t。使用泡沫渣埋弧操作后，钢液的升温速度由原来的3．5℃／min提高到7．5℃／min，45钢出钢[S]为0．012％～0．020％，[P]0．005％～0．007％，电弧炉的炉龄由原来的50炉提高到150炉。     

白渣出钢——有效地脱硫和生产纯净钢

位于宾西法尼亚的Sharon钢公司于1994年末被Caparo集团收购。原有的电弧炉和60“热带材轧机恢复使用，并投入生产。最初的产品大纲是利用下注法生产的铝镇静中碳和低碳热带材。在最初的六个月的生产中，最终铝含量是0．010％—0．025％。为提高钢的整体质量，开发出利用团块“白渣”材料的钢包渣操作。其目的是形成流动的、与耐火材料相容的低FeO MnO渣，在出钢过程中，有效地降低硫含量，回收可氧化的合金。采用该操作后，最终硫含量最高为0．010％。     

淮钢70tUHP电弧炉能量平衡分析

1　能量平衡分析对电弧炉进行能量平衡分析的目的是实现以最低能耗成本生产出温度合格的钢水。淮钢 70ｔＵＨＰＥＡＦ能量指标要素包括供电制度、吹氧制度、烧嘴制度、二次燃烧制度和铁水热装制度等。能量平衡分析的依据是能量守衡定律 ,即 :“Ｅ供 =Ｅ消 Ｅ损 。”根据分析所得 70ｔＵＨＰ电弧炉能量平衡示于图 1。图 1　淮钢 70ｔＵＨＰＥＡＦ能量平衡简图Ｆｉｇ .1　Ｓｃｈｅｍａｔｉｃｏｆｅｎｅｒｇｙｂａｌａｎｃｅｆｏｒａ 70ｔＵＨＰｅｌｅｃｔｒｉｃａｒｃｆｕｒｎａｃｅａｔＨｕａｉｙｉｎＳｔｅｅｌ2　能量供应 (Ｅ供)淮钢 70ｔ…     

The value of physical examination in the diagnosis of patients with blunt abdominal trauma: a retrospective study

Between 1 January 1993 and 1 January 1994, 204 consecutive patients with possible blunt abdominal injury were analysed retrospectively. All patients underwent a standardized diagnostic approach on admission to the emergency room. Abdominal ultrasound (AUS) was performed in all cases. If there was evidence of intra-abdominal injury on physical examination or AUS, without signs of persistent hypovolaemia after initial assessment, contrast-enhanced computed tomographic scanning (CECT) of the abdomen was carried out without exception. Physical examination was equivocal in 13 and 3 per cent, respectively, of patients with 'isolated' abdominal trauma (N = 23) or with fractures of lower ribs 7-12 as a sole diagnosis (N = 30). In multiple injury patients (N = 95) or those with suspected 'isolated' head injury (N = 56), these figures reached 45 and 84 per cent, respectively. AUS (N = 204) revealed intra-abdominal injury in 20 per cent of patients, and CECT (N = 43) resulted in additional information in 49 per cent. Patients with 'isolated' head injury showed 9 per cent abnormalities on abdominal evaluation versus 32 per cent in multiple injury patients. In lower rib fractures (7-12) in multiple injury patients abdominal injury was diagnosed in 67 per cent of the cases. We conclude that: (1) negative findings following reliable physical examination of patients with 'isolated' head injury show very high values (NPV 100 per cent), but reliable physical examination is very infrequent (16 per cent); (2) NPV in lower rib fractures due to low energy impact is very high (100 per cent), with a reliable physical examination in most patients (97 per cent); (3) in patients with isolated abdominal trauma 87 per cent have a reliable physical examination with a moderately high NPV (71 per cent); (4) almost half the multiple injury patients have an unequivocal physical examination (45 per cent), with a high NPV following reliable physical examination for abdominal injury (85 per cent); (5) abdominal ultrasonography should be the first step in the radiological assessment of all patients with possible blunt abdominal injury; (6) in multiply injured patients with fractures of their lower ribs (7-12) due to high energy impact the incidence of abdominal injury is very high and CECT might be indicated even in the case of normal AUS findings.     

Anxiety and depression as a hidden problem in primary health care. Only one case in four identified

Of 374 unselected primary care patients assessed with the Hospital Anxiety and Depression (HAD) scale, 11.8 per cent rated themselves as suffering from anxiety, and 3.7 per cent as depressed. Clinically, 8 per cent were diagnosed as cases of anxiety, and 4 per cent as cases of depression, but agreement was very poor between these cases and those elicited with the HAD scale, only 25 per cent of the latter being identified by the primary care physicians. One third of the patients with a clinical diagnosis of anxiety and 47 per cent of those with diagnosed depression were offered appropriate treatment, usually medication with a selective serotonin re-uptake inhibitor (SSRI) and consultation with a medical social worker. The results were consistent with the expected prevalences, thus indicating anxiety and depression to be markedly under-diagnosed and under-treated, and suggest that there is a manifest need of consultation facilities and of further education among primary care physicians.     

Results of specific immunotherapy with Allergovit in patients with pollen allergy

The immunotherapy among patients with pollen allergy was performed by individuals composed Allergovit. The effects of this treatment was compared to patients with pollenosis who don't have desensitization because they would'nt it. This results indicated that is need to do the nasal provocation test before the choice of antigens for the specific immunotherapy because the prick skin test was very often positive but patients don't have the symptoms. Precise composition of the vaccine improved the course in first season in 77.9 per cent, in second season in 87.5 per cent and in third season in 91.6 per cent.     

Physical rehabilitation of the old, old patient

An increasing number of persons over the age of 85 are surviving acute illnesses and are being referred for physical rehabilitation. There have been no reports in the United States literature about the effectiveness of rehabilitation for this age group. Results of treatment of 97 patients (one hundred consecutive admissions) who were referred by four general hospitals to a suburban physical rehabilitation center were examined and the patients followed for six to 18 months. Seventy-nine per cent of the patients showed improvement, 18 per cent stayed the same, and 3 per cent worsened. Seventy-one per cent either returned to the same setting as before hospitalization or moved in with family members after treatment. These results show that well-planned rehabilitation is effective in the very old patient.     

Frequency of N. gonorrhoeae, T. vaginalis, and C. albicans in female venereological patients. A one-year study

The frequency of Neisseria gonorrhoeae, Trichomonas vaginalis, and Candida albicans has been studied over a period of one year in women attending a venereal diseases clinic. A total of 1,347 women were investigated, all coming from the same catchment area. Gonorrhoea was established at the first visit in 506 patients (38 per cent.), who constituted 97.5 per cent. of the total number of cases of gonorrhoea. Trichomonas vaginalis was found in 272 (20 per cent.) and Candida albicans in 233 (17 per cent.). 176 patients (13 per cent.) had more than one pathogen. Of the patients attending, 22 per cent. (292 women) were so-called "named contacts". The frequency of gonorrhoea established at the first visit in these patients (64 per cent.), was significantly higher, but the frequency of symptoms did not differ from that in other gonorrhoea patients. The number of asymptomatic cases was so large that a single compulsory examination is undoubtedly very useful from the epidemiological point of view, but the value of repeated specimen collections for gonorrhoea is debatable. Complications of gonorrhoea were observed in 29 patients (6 per cent.) at the first visit.     

Example of active therapeutic follow-up: itraconazole

The systematic fungal infections are very serious diseases, the crude mortality in invasive aspergillosis reaches 75 to 100 per cent. Systemic mycosis tends to develop in immunocompromised patients with subsequent physiopathological state, causing a risk of impairment in their digestive absorption potential; in addition these patients are polymedicated and the emergence of multiple drug interactions is frequent. Itraconazole is a very potent antifungal drug with large safety margin and the drug monitoring to maintain a satisfactory plasma level. Immunocompromised patients with suspected malabsorption and treated with oral capsule itraconazole were monitored during two years. In such difficult patients (approximately equal to 500 cases), the result has shown good trough steady-state plasma levels in 72 per cent and insufficient in 28 per cent of the observed patients. However concomitant treatments with antacids produce, in a lot of cases (approximately equal to 48 per cent), a noticeable decrease of the itraconazole availability for these patients. A training program was established to perform the analytical determination of itraconazole and hydroxyitraconazole in biological samples by HPLC method. Analytical validation procedures were associated to this training program which included 115 scientific, technical staff (pharmacists, biochemists ...) from 56 hospitals and institutes.     

A novel invertase from a thermophilic fungus Thermomyces lanuginosus: its requirement of thiol and protein for activation

BACKGROUND: In April 1988, Family Credit families lost their right to free school meals. They were compensated by an increase in Family Credit of 65p per child per schoolday, subsequently uprated by the retail price index. Families on Income Support continued to be entitled to free school meals. The impact of this legislation on the uptake of school meals has not been documented. METHODS: The uptake of school meals by Family Credit and income Support families over a decade was examined in two samples, each consisting of about 7000 English primary school children, one of "inner city' children and the other more representative of the whole population. RESULTS: The change in legislation resulted in an immediate drop in uptake by Family Credit children of around 30 per cent in both samples. By ethnic group, 42 per cent of the Asian Family Credit children changed from school meals compared with 10 per cent of the Afro-Caribbean children. Income Support children continued to have high uptake of about 90 per cent. By the early 1990s, half of the Family Credit children were not taking school meals, and the price of school meals was more than the allowance in 81 per cent of the areas in the representative sample, and in 45 per cent of the inner city areas. CONCLUSION: Uptake of school meals is very sensitive to changes in welfare policy. Monitoring the impact of these changes on children's health and welfare in families with low resources continues to be an important activity.     

Effect of allowing for ethnic group in prenatal screening for Down's syndrome

We conducted a study to investigate ethnic group differences in levels of serum markers used in screening for Down's syndrome [serum alpha-fetoprotein (AFP), unconjugated oestriol (uE3), total human chorionic gonadotrophin (hCG), free alpha- and free beta-hCG, and dimeric inhibin-A], to estimate the extent to which maternal weight differences between ethnic groups explain these differences, and to estimate the effect of adjusting for ethnic group and maternal weight on screening performance. Serum measurements were taken from women who were screened prenatally for Down's syndrome. AFP, uE3, and hCG concentrations were available from 9462 white, 4215 black, and 4392 South Asian women with singleton pregnancies without Down's syndrome or neural tube defects between 15 and 22 weeks' gestational age. Frozen serum samples were available from a subset of 922 white, 449 black, and 135 South Asian women and were used for measurement of free alpha-hCG, free beta-hCG, and inhibin. Values were expressed as multiples of the median (MOM) for women of the same gestational age. There were statistically significant differences in the serum marker levels between ethnic groups that were not explained by differences in maternal weight. The main differences were found in black women compared with white women; black women had serum AFP levels 22 per cent higher (95 per cent confidence interval 20-24 per cent), total hCG levels 19 per cent higher (16-22 per cent), and free beta-hCG levels 12 per cent (3-21 per cent) higher. The other differences were less than 10 per cent. Adjusting for ethnic group only had a small estimated effect on screening performance: a maximum of about 0.5 per cent extra detection at a 5 per cent false-positive rate. At a fixed risk cut-off level, the false-positive rate will not be materially different between different ethnic groups. Adjusting serum markers for ethnic groups improves Down's syndrome screening performance to a very small extent. It is worthwhile because of its established value in AFP screening for open neural tube defects.     

The management and natural history of severe dysplasia and carcinoma in situ of the uterine cervix

From 1951 to 1972, a total of 631 cases of invasive carcinoma of the cervix were diagnosed in Frederiksberg, Copenhagen, Denmark. Treatment was either by surgery or radiotherapy, a combination of both being rarely used. The crude five-year survival rates were 99 per cent in stage Ia, 79 per cent in stage Ib, 67 per cent in stage IIa, 45 per cent in stage IIb, 23 per cent in stage III, 5 per cent in stage IV and 63 per cent for all stages. The relative survival rates were respectively 100 per cent, 81 per cent, 73 per cent, 48 per cent, 26 per cent, 5 per cent and 66 per cent. Radical hysterectomy were found more effective than radiotherapy in stage Ib carcinoma of the cervix. This difference was not explained by age but other factors possibly playing a role are considered. The combination of surgery and radiotherapy is discussed and only seems indicated for patients with stage Ib carcinoma and lymph node metastases.     

Bilithiasis (cholenephrolithiasis)

The study covers 232 patients with chronic calculous cholecystitis, operated in the Surgical Clinic of the Military Hospital--Plovdiv over the period 1991 through August 1995. Bilithiasis (cholenephrolithiasis) is diagnosed in 26 cases (11.2 per cent). This is a condition running a clinical course characterized by pain in the right subcostal and lumbosacral regions, accompanied by nausea and vomit in 57.7 per cent. Eighteen patient sustain renal crisis. Palpatorily, pain is established in the right subcostal region, and positive succussio renalis--in twelve patients. In nine patients there is evidence of albuminuria and leukocyturia (34.6 per cent). In 26 cases the echographic study reveals presence of concretions in the gallbladder, and in all of them-renal calculi too (left kidney--9, right kidney--9, and bilaterally--8 patients). Intraoperatively, concretions in the gallbladder are found in all patients, with hydrops and empyema of the gallbladder documented in five, and vesicoduodenal fistula in one (23 per cent), whereas in the patients free of urolithiasis they amount to 10.8 per cent which points to a reciprocal aggravation of the two pathological conditions. The early, as well as the long-term results of the operative management applied are estimated as very good.