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81.
选择了铁基、镍基、5A分子筛和矾土4种催化剂,在固定床反应器条件下对焦油组分(以1-甲基萘为模型化合物进行了催化裂解研究,结果表明这4种催化剂对1-甲基萘的裂解都具有很好的催化活性,其中镍基催化剂和5A分子筛的催化性能更好,它们在550℃,空速3000h^-1的条件下反应100h,其催化活性未降低。同时还研究了在这两种催化剂条件下温度和空速对转化率的影响,按一级反应线性回归得出两种催化剂在250 ̄ 相似文献
82.
目的 对26例肝硬化合并低氧血症患者进行血气分析,探讨肝硬化合并低氧血症的发病机理及发生率。方法 用美国生产的IL1306型血气分析仪,测定26例肝硬化患者及8例正常人动脉血中PaO2、SaO2、PaCO2及pH值。比较两组之间的差异。结果 研究组与对照组比较,研究组PaO2明显下降,P〈0.01,研究组中低氧血症的发生率达53.8%。结论 肝硬化如出现并发症或肝贮备功能下降者合并低氧血症发生率明 相似文献
83.
随机将 51例脑出血急性期患者分为逐瘀化痰汤组 (观察组 )及常规西药治疗对照组 ,各观察2 0d ,分别测定PaO2 、PaC0 2 、SAT及微量元素锌铜值。结果 ,观察组PaO2 、SAT治疗前后有显著性差异 ;余两组间及组内均无显著性差异 ,但观察组优于对照组。推测逐瘀化痰汤纠正了脑出血后的脑细胞缺氧状态 ,提高了缺氧耐受性 ,但对微量元素锌铜的影响不明显 相似文献
84.
85.
The changes in the anthropometric data and urine steroid metabolites caused by regular training in children in two age groups (11 and 14 years old) were investigated. The skinfolds of older girls participating in regular athletic, swimming or soccer training were thinner compared with age-matched control groups (P < 0.01) and their body mass and constitution were lower (P < 0.05). In the other groups no significant differences were observable in the anthropometric parameters. The trained children in all groups had significantly higher exercise times on the cycle ergometer (P < 0.01, in young boysP < 0.05). The strength of their hands was lower in three trained groups: in younger boys (P < 0.05), in younger girls (P < 0.01) and in older girls (right handP < 0.01, left handP < 0.05). The urinary excretion of androsterone (P < 0.02), 11-ketopregnanetriol (P < 0.01) and pregnenetriol (P < 0.02) was decreased in the older trained girls; pregnenetriol was increased in younger boys (P < 0.05). Urinary excretion of cortisol metabolites was increased in trained boys [in younger boys: tetrahydrocorticosterone (P < 0.05) and 20-hydroxycortisol (P < 0.05); in older boys allotetrahydrocortisol (P < 0.02), cortisol (P < 0.05) and 20-hydroxycortisol (P < 0.05)]. There were no significant differences in the younger girls. In the trained older girls urinary excretion of cortisol metabolites was decreased: tetrahydrocortisone (P < 0.02), allotetrahydrocorticosterone (P < 0.01), tetrahydrocortisol (P < 0.05), -cortolone (P < 0.01), cortisol (P < 0.02), 6-hydroxycortisol (P < 0.01) and 20-hydroxycortisol (P < 0.05). A multivariate analysis of the data from the trained groups and sedentary, age-matched control groups showed that regular training has a significant effect on steroid excretion. 相似文献
86.
A. C. M. Schrikker H. Wesenhagen S. C. M. Luijendijk 《Pflügers Archiv : European journal of physiology》1995,430(5):862-870
In this study we have investigated the effects of breath holding and of the physical properties of gases on four different respiratory dead spaces (V
D): the Fowler, the physiological, the washout and the inert gas dead space. The experiments were performed with dogs which were ventilated artifically with breathing patterns with different post-inspiratory breath holding times (t
a) of 0, 0.5, 1.0 and 2.0 s. Tracer amounts of acetone, ether and enflurane were infused continuously into a peripheral vein and a bolus of a mixture of krypton, Freon12 and SF6 was introduced into the peritoneal cavity. After reaching steady state, samples of arterial blood, mixed venous blood and mixed expired air were taken simultaneously. From the partial pressures (P
a, P
¯V and P
respectively) we determined the excretion (=P/P¯V), retention (R=Pa/P¯V) and the physiological dead space fraction (V
D,phys/V
T=(1 P/Pa) for each gas, where V
T is tidal volume. Further, we recorded the expirograms of the six tracer gases and of CO2 from which the Fowler dead space fractions (V
D,Fowler/V
T) of the different gases were determined. Also the washout dead space fractions (V
D,washout/V
T) for He and SF6 were determined as well as the inert gas dead space fraction (V
D,MIGET/V
T) with the use of the multiple inert gas elimination technique (MIGET).With the exception of V
D,phys/V
T for SF6, all dead space fractions decreased with increasing t
a. V
D,phys/V
T for the poorly soluble gas SF6 was considerably larger than V
D,phys/V
T for the remaining gases. For the highly soluble acetone V
Fowler/V
T was considerably smaller than V
D,Fowler/V
T for the other gases. V
D,washout,SF6/V
T was always larger than V
D,washout,He/V
T and V
D,Fowler,SF6/V
T. Further, V
D,phys/V
T was larger than V
D,Fowler/V
T for SF6 and acetone. However, for gases with intermediate solubility in blood V
D,phys/V
T tended to be smaller than V
D,Fowler/V
T. We conclude that the respiratory dead spaces are affected by the breathing pattern and by the physical properties of gases, i.e. their diffusivity in alveolar gas and their solubility in blood or lung tissue. 相似文献
87.
Background Patient discomfort 0–24 h after double-contrast barium enema (DCBE) was investigated in two ways.Methods In part 1, 139 patients, not previously informed, were contacted by telephone to assess symptom rates without bias. In part 2, designed as a prospective randomized double-blind trial, the effect of carbon dioxide (CO2) as an insufflating gas was compared with conventional atmospheric air (AA).Results Part 1: 10% experienced severe abdominal pain, and 18% severe abdominal distention. Part 2: Low discomfort rates were found for both severe pain (7% for AA vs. 2% for CO2) and severe distention (13% for AA vs. 8% for CO2); the differences were not significant. In both parts of the study, female patients with a history of abdominal discomfort of colon irritabile type were significantly overrepresented in the severely symptomatic groups. Equal numbers of patients experiencing severe abdominal distention for the first time were found in both the AA and CO2 groups, ruling out AA as the sole cause of these symptoms.Conclusion Abdominal post-DCBE discomfort seems to be less frequent than previously reported and is not effectively eliminated by CO2. We still find the use of AA in DCBEs justified. 相似文献
88.
利用垃圾填埋气体发电走垃圾处理资源化道路 总被引:3,自引:0,他引:3
城市生活固体弃物经卫生填埋后,产生的洁气可以做为资源加以利用。杭州市天子岭废弃物处理场1998年建成中外合作的发电厂,利用沼气并网发电,不但学习了国外的先进技术,而且培养自己的技术,管理人员。 相似文献
89.
In this paper a micromachined electrochemically driven pump capable of dosing precise nanoliter amounts of liquid is presented. The pump consists of a micromachined channel structure realized in silicon by reactive ion etching. On top of this structure a Pyrex((R)) cover piece with noble metal electrodes was bonded. The fluid to be dispensed is stored in a meander shaped reservoir which is part of the channel structure. This meander starts in an electrolyte solution containing reservoir, on top of which two noble metal electrodes are positioned. By the electrochemical production of gas bubbles by electrolysis of water at these electrodes, liquid can be driven out of the meander. The measured volume displacements were in close agreement with theory. Pump rates as low as a few nl/s could accurately be controlled via the actuation current through the electrodes. By applying current pulses rather than a continuous current, preset amounts of fluid in the nanoliter range could be dosed successfully. Because the resulting device consists of simple channel structures and metal electrodes it can easily be integrated in miniaturized chemical analysis systems to dose reagents or calibration solutions. 相似文献
90.
目的:评价视网膜玻璃体手术中利用原裂孔气液交换联合C3F8气体眼内填充治疗复杂性视网膜脱离的效果。方法:对51例(51眼)复杂性视网膜脱离患者采用环扎加压术加玻璃体切除术、利用原裂扎进行气液体交换(Fluid-Airexchange简称FA)后眼内填充C3F8气体,其中22例(22眼)行完全FA术,29例(29眼)行不全FA术。结果:观察术中并发症及术后1周眼内气量、眼压及视网膜复位情况,全FA组与不全FA组比较术后第1天眼内气体充满及始终未充满病例有明显差异(P<0.05),其余情况均无明显差异(P>0.05)。结论:利用原裂孔进行气液交换,并采用不同剂量C3F8眼内填充是一种较为简单可行的手术方法。 相似文献