构筑企业级信息系统安全体系

本文以跨地区公司为例,探讨企业级信息系统安全体系的构筑,所述的原则和做法可以实现在外部网-内部网-主机-用户体系上,形成多道防线,使企业计算机网络具有相当程度的安全性,从而达到企业信息系统的安全目标。     

Perfluorocarbons are effective oxygen carriers in cardiopulmonary bypass

Intravascular perfluorochemical (PFC) emulsions together with a high oxygen (O2) tension may increase the delivery of dissolved O2 to useful levels. A severely anemic model of cardiopulmonary bypass (CPB) was used to test the hypothesis that a novel PFC emulsion (PFCE; Oxygent [Alliance Pharmaceutical Corp., San Diego, CA] 90% w/v perflubron) used at a high PO2 during bypass delivers sufficient O2 to ameliorate hypoxic myocardial contractile dysfunction. Acutely anemic dogs (N = 42; hematocrit = 15.8 +/- 0.6% [mean +/- SEM] before CPB and 10.9 +/- 0.1% during CPB) were divided into four groups. Group 1 was a control (n = 12). As CPB was initiated, groups 2 (n = 10), 3 (n = 10), and 4 (n = 10) had 1.35 g PFC.kg-1, 2.7 g PFC.kg-1, or 5.4 g PFC.kg-1 added via the venous return cannula. Pre-CPB and post-CPB cardiac function was measured by the first derivative of left ventricular pressure (dP/dtmax). The dP/dtmax on separation from CPB was: group 1, 619 +/- 96; group 2, 738 +/- 56; group 3, 782 +/- 101; and group 4, 828 +/- 100 (p < 0.05 groups 3 and 4 versus group 1). Mortality during the first hour after separation from CPB was higher in group 1 than in PFCE treated dogs; however, this trend did not attain statistical significance (p < 0.065). The PFC dose was higher in survivors than in nonsurvivors (2.6 +/- 0.4 g PFC.kg-1 versus 1.2 +/- 0.5 g PFC.kg-1; p < 0.05). A PFCE used at a high PO2 provides sufficient physically dissolved O2 to relieve myocardial hypoxic injury in a severely anemic model of CPB. Current PFCEs are effective O2 carriers. This finding suggests that they can be used as a temporary erythrocyte substitute to diminish the need for allogeneic transfusions during cardiac operations.     

潮汐河口平面二维非恒定流数值模拟

本文基于三角形网格划分，采用有限元法，建立了平面二维非恒定潮流数学模型。采用了质量集中、压缩存储的处理方法和“预估校正”的时间推进算法，较好地解决了有限元计算存储量和计算速度问题。对长江口南北支河段进行了验证计算，结果表明模型能较好模拟长江口南北支河段的潮流运动情况，且计算稳定性好、速度快、精度高。     

PAN聚合物一次性溶解新技术

阐述了一个全新的聚丙烯腈高聚物溶解理论，取代了以往人们思维中的高聚物大分子必须经过先溶胀再溶解的漫长的静态溶解过程。对于年产50kt/a腈纶装置可减少一次性投资约1500万元，减少运转费用360万元／a，在现有腈纶大装置上实施，经济效益十分可观。     

热老化聚丙烯薄膜宏观力学性能及微观结构的研究

通过对热老化处理的聚内稀薄膜进行X射线衍射实验.对测得的实验数据采用X射线衍射线形分析理论处理,同时对热老化聚丙烯薄膜进行拉仲形变测量,得到材料的力学性质和微晶尺寸及内部点阵畸变的变化规律.从而将热老化聚丙烯材料宏观性质变化与微观结构联系起来,找出材料聚集态精细结构随老化时问而改变的微观规律.     

Diagnosis of asthma and chronic obstructive pulmonary disease in general practice

There may be an overlap between the clinical pictures of asthma and chronic obstructive pulmonary disease which hampers a clear distinction between the two diseases. Most symptoms presented by patients do not clearly belong exclusively to either asthma or chronic obstructive pulmonary disease. By the nature of their discipline and training, general practitioners focus mainly on symptoms presented, which do not give a decisive answer in the differential diagnosis between the two diseases. Therefore, general practitioners must rely on objective parameters, such as determining the presence and degree of reversibility of airway obstruction, diurnal peak flow variability, bronchial hyper-responsiveness and allergy. This paper puts forward a pragmatic, primary care definition of asthma and chronic obstructive pulmonary disease.     

Endoscopic injection therapy for bleeding peptic ulcer; a comparison of adrenaline alone with adrenaline plus ethanolamine oleate

One hundred and seven consecutive patients presenting with significant peptic ulcer haemorrhage were randomised to endoscopic injection with 3-10 ml of 1:100,000 adrenaline (55 patients, group 1) or to a combination of adrenaline and 5% ethanolamine (52 patients, group 2). All had major stigmata of haemorrhage and endoscopic injection was undertaken by a single endoscopist. The groups were well matched with regard to risk factors. Rebleeding occurred in eight of the group 1 patients and seven in the group 2 patients; surgical operation rates, median blood transfusion requirements, and hospital stay were similar in both groups. The efficacy of either form of injection was similar whether patients presented with active bleeding or a non-bleeding visible vessel. No complications occurred. In patients presenting with significant peptic ulcer bleeding, the addition of a sclerosant confers no advantage over injection with adrenaline alone.