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Distribution of gasses to the cast volume and volume of pores can be maintained within the acceptable limits by means of correct setting of technological parameters of casting and by selection of suitable structure and gating system arrangement. The main idea of this paper solves the issue of suitability of die casting adjustment—i.e., change of technological parameters or change of structural solution of the gating system—with regards to inner soundness of casts produced in die casting process. Parameters which were compared included height of a gate and velocity of a piston. The melt velocity in the gate was used as a correlating factor between the gate height and piston velocity. The evaluated parameter was gas entrapment in the cast at the end of the filling phase of die casting cycle and at the same time percentage of porosity in the samples taken from the main runner. On the basis of the performed experiments it was proved that the change of technological parameters, particularly of pressing velocity of the piston, directly influences distribution of gasses to the cast volume.  相似文献   

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Characterization of the beta-adrenoceptor of the adipose cell of the rat   总被引:3,自引:0,他引:3  
The dose-response curves of the beta-adrenergic agonists isoprenaline (mixed beta 1 and beta 2), prenalterol (beta 1-selective), noradrenaline (more beta 1 than beta 2) and salbutamol (beta 2-selective) were studied on adipose cells of the rat, in vitro. The observed lipolytic potencies were in the order: isoprenaline greater than noradrenaline greater than salbutamol greater than prenalterol. The effects of beta-adrenergic antagonists betaxolol (beta 1-selective) propranolol (non-selective) and ICI 118551 (beta 2-selective) on lipolysis stimulated by the various beta-adrenergic agonists showed that in each case propranolol was the most potent blocking agent. These observations are not compatible with the concept that regulation of lipolysis in adipose tissue is mediated exclusively either by adrenergic receptors of the classical beta 1 type, or of the classical beta 2 type. We propose therefore, that this beta-adrenergic receptor, because of its non-compliance with the current classification system, be termed a 'beta-3' or beta-hybrid' adrenoceptor. Thus cardio-selective beta-adrenergic blocking agents, like betaxolol, may offer a hitherto unrecognized clinical advantage in obese patients undergoing anti-hypertensive therapy by offering a reduced impediment to hormone-induced utilization of calorie stores in adipose tissue.  相似文献   

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目的本文旨在了解医务人员现代结控知识掌握的现状及培训效果?方法于培训前后进行问卷调查,内容包括:病例发现?结核病诊断及化疗?结果培训前疫情报告和转诊,回答正确者占75.2%?71.7%;对临床表现?查痰和诊断依据,回答正确者占83.5%?42.5%?40.8%;抗痨药物?用药方法?化疗原则?短化方案?短化疗程?治愈标准六项,回答正确者占58%?14.4%?20.8%?9.2%?17%?24.3%?培训后再次调查发现,90%以上医务人员对现代结控基本知识已掌握?结论各级医务人员现代结控知识是很贫乏的,因此,对其进行系统培训是极为必要的,此项工作省时?省力?投入少,可收到事半功倍的效果。  相似文献   

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The high concentration of the diagnoses among the categories of death causes is called the concentration of death causes. The idea of diversity used in statistical ecology is in a sense a contrary concept. Introducing the investigation of diversity indices on epidemiological material, we have shown sexual differences and age characteristics of the latter. In the course of the investigations, there was an opportunity to measure exactly and analyse the high increase of the concentration of death causes at an older age. In this paper we related the changes due to age to the structure of the set of specific death rates and to that of hazard functions. According to our fitting investigations, the majority of the elements of the set of curves could be well approximated by the Gompertz or by the Weibull function. In this case, a mathematical explanation can be given to the increase, then decrease of Hill's diversity indices, that is, to the decrease, than increase of the concentration of death causes. Finally we point briefly to the evolutionary aspects of the discussed changes with age of this concentration.  相似文献   

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In 9 young men, healthy volunteers, we studied the effect of dry swallows, liquid and paste swallows on the pharyngeal motility. The viscosities of liquids and past were 200 centipoise (cP), 300 cP and 60000 cP, respectively. The bolus volume was 10 ml. For pharyngeal manometry we used two strain-gauge manometric probes taped together, so that a total of six transducers were staggered at 1.5 cm intervals. After its passage through the nose, the assembly was positioned so that all its transducers faced posteriorly, and manometric activity was recorded from oropharynx, hypopharynx and upper esophageal sphincter (UES). We also recorded infra-hyoid electromiographic activity. The amplitude and duration of the oropharyngeal and hypopharyngeal peristaltic pressure complex were not changed by the different boluses. The velocity of peristaltism propagation between oropharynx and UES was slower for paste than for liquids or dry swallows. The increased of viscosity was associated with longer duration of UES relaxation, and greater intrabolus pressure in hypopharynx and UES. The infra-hyoid electromiographic activity was longer for paste than for liquids or dry swallows. These findings suggest that pharyngeal motility is affected by the characteristics of the swallowed bolus.  相似文献   

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