Effect of extremely high CO2 pressure on the formation of the corrosion film on 13Cr stainless steel

The corrosion behaviors of 13Cr martensitic steel under different CO₂ partial pressures (4–28 MPa) were investigated by weight loss tests and surface characterizations. The results show that the corrosion rate of 13Cr steel shows a sharp increase under higher CO₂ pressure (28 MPa), which reached approximately 20–180 times as large as those under lower CO₂ pressures (4–12 MPa). Under the lower CO₂ pressures, a single-layered Cr(OH)₃ passive film forms and completely covers the steel surface. However, when the CO₂ pressure reaches 28 MPa, a very different corrosion film which contains an inner Cr(OH)₃ passive layer and an outer FeCO₃ layer forms, and the inner passive layer shows local damage. This phenomenon can be explained by the lower pH (∼2.75) and the higher H₂CO₃ concentration in the solution under the higher CO₂ pressure.

The effect of CO₂ partial pressure (up to 28 MPa) on the corrosion of 13Cr stainless steel.     

Influence of fluorinated graphene-modified epoxy coatings on the corrosion behaviour of 2024 aluminium alloy

This study provides an enhanced corrosion resistance of epoxy resin (EP) by embedding fluorinated graphene (FG) into the epoxy matrix. FG with different fluorine contents was obtained by reacting nitrogen trifluoride (NF₃) gas with GO and then incorporated into the EP matrix to fabricate the different composites. Through a series of characterization methods, the chemical composition and microstructures of FG were systematically analyzed, and its corrosion resistance was also studied. Results revealed that F atoms were bonded to the GO surface to form C–F covalent bonds, and an FG lamellar thickness less than 2 nm. The contact angle of the coatings increased with the incorporation of FG, and the coating resistance of FG2/EP coating was 3 orders of magnitude more than that of the EP coating after immersion for 4080 h. Thus, the incorporation of FG into epoxy matrix significantly enhanced its hydrophobic properties and barrier performance, which was beneficial to improving the long-term corrosion resistance of the coating.

This study provides an enhanced corrosion resistance of epoxy resin (EP) by embedding fluorinated graphene (FG) into the epoxy matrix.     

Effect of chloride ions on the corrosion behavior of carbon steel in an iron bacteria system

Reclaimed water used as circulating cooling water can effectively relieve water stress, but the corrosion problem in it is very prominent. In particular, Cl⁻ and iron bacteria (IB) are important influencing factors of corrosion behavior in a circulating water environment, and both of them often coexist in circulating water systems, so it is crucial to study their synergistic effects. This paper investigated the effect of Cl⁻ on the corrosion behavior of carbon steel in the IB system by use of weight loss measurements, electro-chemistry and X-ray photoelectron spectroscopy (XPS). In the first 1–9 days of the experiment, the increase of Cl⁻ concentration led to an increase of corrosion rate and a decrease of anode potential and charge transfer resistance at the interface. The corrosion rate of the 4Cl_IB condition reached 0.45 mm a⁻¹ in the 1st day, which was 1.47 and 1.15 times that of 3Cl_IB and 1Cl_IB, and its anode potential was 22.6% and 33.8% lower than that of 3Cl_IB and 1Cl_IB. This indicates that a higher concentration of Cl⁻ made the anodic reaction easier and the corrosion more severe. However, after 9 days, a decline in the corrosion rate was recorded at similarly high Cl⁻ concentrations. On the 15th day, the corrosion rates for 3Cl_IB and 4Cl_IB were 7.0% and 15.6% lower compared to the 1Cl_IB condition. At this stage, the anode potential and film resistance had increased significantly, to become the dominant factors controlling the corrosion reaction. On the 15th day, the β_a values of 1Cl_IB, 3Cl_IB and 4Cl_IB were 1.2, 1.5 and 1.7 times higher than those of the 1st day, and the highest R_b value of 1592.1 Ω cm² was obtained for the 4Cl_IB condition, which was 1.9 times higher than that of R_ct. In the early stage of corrosion, the surface of the carbon steel was enriched in Cl⁻ due to their high concentration, and the Cl⁻ could easily destroy the developing corrosion product film and promote the generation of Fe²⁺. At the same early stage, the growth of IB was enhanced, and the metabolism of IB was promoting local corrosion. However, in the later stage of corrosion, biofilms had an increasing effect on corrosion. A high concentration of Cl⁻ accelerated biofilm growth and densified the corrosion product layer which subsequently hindered the anodic reaction and thus inhibited corrosion.

In the early stage, Cl⁻ destroys the corrosion product film and promotes localized corrosion. In the later stage, a high concentration of Cl⁻ accelerates biofilm growth and densifies the corrosion product layer, thereby inhibiting corrosion.     

镍铬合金烤瓷冠对人体尿中镍、铬离子的影响

背景：镍铬合金烤瓷冠因其机械性能优良、低廉价格,在国内口腔修复领域广泛应用。目的：观察镍铬合金烤瓷冠对患者尿中镍、铬离子的量的影响。方法：选择2009-03/2010-03在新疆医科大学第一附属医院就诊戴用镍铬合金烤瓷冠患者55例为实验组,同期未做任何修复治疗者55例为对照组,比较2组患者尿中镍、铬的离子水平。结果与结论：镍铬合金冠修复患者尿镍、铬离子水平与对照组接近（P〉0.05）,且镍铬合金烤瓷冠数量〈5个与≥5个的患者的镍、铬离子水平也接近（P〉0.05）,但与使用镍铬合金烤瓷冠〈5年的患者相比,使用年限≥5年者的尿镍、尿铬离子水平升高（P〈0.05,P〈0.01）。提示镍铬合金烤瓷冠修复不会影响患者尿中镍、铬离子水平,但镍铬合金烤瓷冠使用年限会影响患者尿中的镍、铬离子的水平。     

恒温箱内低流量吸氧在早产儿治疗中的应用

[目的]观察恒温箱内低流量吸氧对早产儿缺氧状况的治疗效果。[方法]52例早产儿采用吸氧导管直接插入恒温箱内,使氧气均匀弥散在恒温箱内,让患儿自由吸氧。[结果]51例患儿呼吸改善,血氧饱和度达90%以上,1例缺氧状况无明显改善,改用头罩吸氧。[结论]对于需要恒温箱内保暖的早产儿可采用恒温箱内低流量吸氧法代替鼻导管低流量吸氧法。     

恒温箱内低流量吸氧在早产儿治疗中的应用

[目的]观察恒温箱内低流量吸氧对早产儿缺氧状况的治疗效果。[方法]52例早产儿采用吸氧导管直接插入恒温箱内，使氧气均匀弥散在恒温箱内，让患儿自由吸氧。[结果]51例患儿呼吸改善，血氧饱和度达90％以上，1例缺氧状况无明显改善．改用头罩吸氧。[结论]对于需要恒温箱内保暖的早产儿可采用恒温箱内低流量吸氧法代替鼻导管低流量吸氧法.     

反复熔铸对NEO钴铬烤瓷合金金瓷结合性能的影响

背景:NEO钴铬烤瓷合金不含有害物质,但其钴铬烤瓷合金能否回收利用存在争议,反复熔铸对NEO烤瓷合金性能影响的报道较少。目的:观察反复熔铸对NEO钴铬烤瓷合金金瓷结合力、金相结构、金瓷界面形貌的影响。方法:根据ISO9693标准,采用真空条件下氩气保护加压铸造方法,用三点弯曲实验测试分别经过1～5次熔铸后NEO钴铬烤瓷合金的金瓷结合能力,金相显微镜观察各代铸件金相结构,扫描电镜观察各代试件金瓷结合界面形貌。结果与结论:分别经过1～5次熔铸后的NEO钴铬烤瓷合金的金瓷结合能力差异有显著性意义(P<0.05);随着熔铸次数增加铸件的树枝状结构和晶粒结构逐渐模糊、消失;试件金瓷界面结合逐渐疏松、过渡层厚度增加。提示经过反复熔铸的NEO会明显影响其金瓷结合性能。     

Indentation-induced plastic behaviour of nanotwinned Cu/high entropy alloy FeCoCrNi nanolaminate: an atomic simulation

Using large-scale molecular dynamics (MD) simulations, the effects of interface and layer number in the nanoindentation response of experimentally observed nanotwinned Cu/high entropy alloy (HEA) FeCoCrNi nanolaminate are studied. The dislocations are nucleated and emitted, which are more limited to the first twinning layer > second twinning layer > HEA layer. The stacking fault strengthening is pronounced due to the obvious difference of stacking fault energy between Cu and HEA, which can be rarely observed from the previous work in traditional alloys and metals. After the indentation induced deformation, the nanotwinned Cu/HEA FeCoCrNi nanolaminates for different layer numbers generate a mass of Shockley partial dislocations to cause the good plasticity, attributed to the strong strain gradient effect. The strong layer number and interface structure effects found here can provide insight for the design of advanced nanolaminate with high strength and good plasticity.

Using large-scale molecular dynamics (MD) simulations, the effects of interface and layer number in the nanoindentation response of experimentally observed nanotwinned Cu/high entropy alloy (HEA) FeCoCrNi nanolaminate are studied.     

Effects of vasopressin on left anterior descending coronary artery blood flow during extremely low cardiac output

Because of the possibility of vasopressin-mediated coronary vasospasm, this study was designed to assess effects of vasopressin compared to saline placebo on left anterior descending (LAD) coronary artery blood flow. Twelve anaesthetized domestic swine were prepared for LAD coronary artery blood flow measurement with ultrasonic flow probes, using cardiopulmonary by-pass adjusted to 10% of the prearrest cardiac output. This 10% value approximates that reported for cardiac output during conventional closed-chest CPR. After 4 min of untreated ventricular fibrillation, and 3 min of cardiopulmonary by-pass blood flow, 12 pigs were randomly assigned to receive intravenously, every 5 min, either vasopressin (0.4, 0.4, and 0.8 U/kg; n = 6) or saline placebo (n = 6). The mean +/- S.D. LAD coronary artery blood flow in the vasopressin and placebo pigs was comparable before cardiac arrest, and during cardiopulmonary by-pass low flow; but increased significantly (P < 0.05) 90 s after each of three vasopressin injections compared to placebo (78 +/- 1 versus 42 +/- 2 ml/min; 62 +/- 2 versus 36 +/- 1 ml/min; and 54 +/- 1 versus 27 +/- 1 ml/min), respectively. Coronary vascular resistance decreased significantly (P < 0.05 ) 90 s after each of three vasopressin and placebo injections. In this model, repeated bolus administration of vasopressin, given during simulated extremely low cardiac output improved LAD coronary artery blood flow to prearrest levels without affecting coronary vascular resistance. Conclusions: during extremely low blood flow using cardiopulmonary by-pass, vasopressin improves LAD coronary artery blood flow without affecting coronary vascular resistance.     

Effect of the Y-piece of the ventilation circuit on ventilation requirements in extremely low birth weight infants

Objective Volutrauma caused by high tidal volumes contributes considerably to the development of bronchopulmonary dysplasia. Yet high tidal volumes are required to overcome dead space. In an experimental arrangement we tested whether reduction of dead space might reduce ventilation requirements and thus reduce volutrauma in preterm infants.Materials and methods The time required to eliminate CO₂ by standardized mechanical ventilation from a preterm infants test lung flooded with CO₂ was measured. Four different Y-pieces and flow sensor combinations were tested with and without a device for closed suction: Y-piece without flow sensor; integrated flow sensor; small dead-space flow sensor; and a new dead-space free-flow sensor for preterm infants. CO₂ concentrations were measured by a capnograph. Mean CO₂ elimination times (±SD) were compared.Results Mean CO₂ elimination time was 37.5 s (±1.18 s) with and 37.4 s (±0.97 s) without closed suction device for the Y-piece without flow sensor, 47.7 s (±0.82 s) and 45.5 s (±1.18 s) for the integrated flow sensor, 42.5 s (±1.27 s) and 41.1 s (±0.99 s) for the small dead-space flow sensor and 38.3 s (±1.16 s) and 36.8 s (±0.79 s) for the dead-space free-flow sensor.Conclusion CO₂ elimination time with and without closed suction device was nearly identical for the Y-piece without flow sensor and for the dead-space free-flow sensor. With both systems, ventilation requirements were significantly lower than for the integrated flow sensor and for the small dead-space flow sensor (integrated flow sensor vs dead-space free-flow sensor 23.6 and 24.5%, respectively, small dead-space flow sensor vs dead-space free flow sensor 11.7 and 10.9%, respectively); thus, we think that introduction of the innovative dead-space free-flow sensor into clinical practice might reduce incidence and severity of bronchopulmonary dysplasia by reduction of volutrauma.The new dead-space free flow sensor was patented in Austria by M. Wald, who acted as a private person. A reservation for a possible worldwide patent was made. The study was performed without any financial support by a commercial institution or company.     

提高极低出生体重儿存活率的护理研究

目的研究护理措施在极低出生体重儿存活率中的作用。方法按我院新生儿病区监护室 (NICU)建立的前后 ,分为前五年组 (1989～ 1993年 )和后五年组 (1994～ 1998年 ) ,比较两组极低出生体重儿并发症的发生率、存活率。结果两组极低出生体重儿的胎龄、出生体重构成比差异无显著意义 (P〉0 .0 5 )。主要并发症呼吸系统疾病的病死率 ,严重感染的病死率和颅内出血的发生率 ,后五年组较前五年组均下降 ,差异均有显著性意义 (P〈0 .0 5 )。结论建立NICU ,加强对护士的培训 ,提高护士对重症监护的整体护理水平 ,配合医疗 ,是提高极低出生体重儿存活率的关键。     

Effect of the composition of very low and low density lipoproteins on the rate of cholesterylester transfer from high density lipoproteins in man, studied in vitro

The process of cholesterylester (CE) transfer is supposed to be a regulatory factor in the distribution of CE between lipoproteins. In addition to the activity of CE transfer protein, this process may be affected by acceptor lipoprotein characteristics. In this study the effect of the composition of different very low density lipoproteins (VLDL) and low density lipoproteins (LDL) on the ability to accept CE from HDL in vitro was investigated. [3H]-CE high density lipoprotein (HDL) (100 nmol CE) from one batch was incubated with VLDL (75 nmol CE), isolated from fifteen subjects for 4 h and separately with LDL (250 nmol CE), isolated from thirteen subjects for 16 h, both in the presence of lipoprotein-free plasma providing a source of cholesterylester transfer protein. The CE transfer rate of VLDL (range 1.34-2.84% [3H]-CE transferred h-1) was correlated to the triacylglycerol (TG):CE molar ratio (r: 0.63, P less than 0.05), to the phospholipid (PL):CE molar ratio (r: 0.75, P less than 0.01), to the protein (Pr):CE ratio (expressed in g nmol-1) (r: 0.72, P less than 0.01) and to the free cholesterol (FC):CE molar ratio (r: 0.69, P less than 0.01), but not to the FC:PL molar ratio (r: -0.08, NS). The CE transfer rate to LDL (range 1.18-3.59 nmol CE h-1) was correlated to the Pr:CE ratio (r: 0.72, P less than 0.01) and inversely to the FRC:PL molar ratio (r: -0.88, P less than 0.001), but not to the TG:CE molar ratio (r: 0.40, NS), nor to the FC:CE molar ratio (r: -0.37, NS).(ABSTRACT TRUNCATED AT 250 WORDS)     

恒温条件下低流量吸氧最佳湿度研究

[目的]探讨低流量氧疗过程中吸入氧气温度在30℃～35℃时,不同湿度对病人氧疗舒适度和依从性的影响.[方法]根据吸氧湿度将75例脑外科病人分为A组、B组、C组、D组、E组,即病室温度22℃,湿度在55％～65％,在氧气加热至30℃～35℃,将A组的吸氧湿度控制在50％以下,B组的吸氧湿度控制在51％～70％,C组的吸氧湿度控制在71％～80％,D组的吸氧湿度控制在81％～90％,E组的吸氧湿度控制91％～100％,3d后比较各组病人的氧疗舒适度和依从性.[结果]5组病人鼻咽部感觉、咳嗽程度、咳痰难度、依从性方面比较差异有统计学意义（P＜0.05）,吸氧湿度在71％～90％时病人舒适度和依从性优于其他组.[结论]低流量氧疗过程中吸入氧气温度在30℃～35℃时,吸氧最佳湿度为71％～90％.     

低流率团注高浓度对比剂在兔脑CTA成像中的效果

目的 探讨低流率团注高浓度对比剂在脑CT血管成像(CTA)中的可行性.方法 18只新西兰白兔随机分为3组,实验组使用A方案(碘迈伦400 mgI/ml,流率0.5 ml/s);对照组分别使用B方案(300 mgI/ml,流率1.0 ml/s)或C方案(400 mgI/ml,流率1.0 ml/s),每次注射对比剂含碘量为0.5 g/kg体重,行脑CT同层动态扫描,获得兔大脑中动脉强化的时间-密度曲线.对比各方案兔大脑中动脉强化峰值到达时间(PT)及到达峰值时大脑中动脉的CT值.结果 大脑中动脉平均强化峰值分别为(164.67±5.16)HU、(163.00±7.13)HU、(193.50±5.13)HU,C方案高于A、B方案(P<0.01),A、B方案之间差异无统计学意义(P=0.63).三组方案测得大脑中动脉PT分别为5 s、5 s、4 s,C较A、B方案提前.结论 在兔脑CTA扫描中,使用高浓度对比剂,可以大大降低注射流率而对血管强化效果无明显影响;在注射流率相同情况下,应用高浓度对比剂可使血管显示更清晰.     

Nutritional influences on the growth of extremely low birth weight infants

Recent advances in the area of neonatal nutrition have contributed to the overall survival rate of extremely low birth weight preterm infants. However, the pathophysiologic conditions that affect these infants influences the overall nutrition plan and ultimately impacts their growth. This article discusses research findings related to the growth of extremely low birth weight infants and the relationship between growth and nutritional care practices. Copyright 2002, Elsevier Science (USA). All rights reserved.     

低分子量肝素对纤维蛋白凝结速率影响的体外研究

目的 应用SONOCLOT血凝分析仪测定不同剂量及不同种类LMWH对纤维蛋白CR的影响,探讨应用CR检测LMWH抗凝活性的可行性.方法 选择20名健康志愿者,抽取所有受试者外周血标本依次加入不同剂量的LMWH(达肝素),最终血标本浓度范围为0～1.8 IU/ml;应用3种不同促凝剂玻璃珠、硅藻土、高岭土分别依次测定CR值,对不同浓度达肝素与相应的CR值进行相关性分析.向外周血标本分别加入相同剂量(最终血标本浓度为0.8 IU/ml)的不同种类LMWH(达肝素、依诺肝素、那曲肝素),应用玻璃珠促凝剂依次测定CR值并进行相关性分析.结果 随达肝素剂量的增加,用3种促凝剂分别测得的CR值均逐渐降低.达肝素浓度为0～1.8 IU/ml时,应用玻璃珠促凝剂测定的CR值为20.0～4.5 IU/min,应用硅藻土促凝剂测定的CR值为26.1～6.6 IU/min,应用高岭土促凝剂测定的CR值为27.2～7.5 IU/min,均与达肝素浓度呈指数相关关系(R2分别为-0.796、-0.884、-0.921,P＜0.01).不同种类LMWH在相同浓度下(0.8 IU/ml)测定的CR值也不同,达肝素作用下测定的CR值为7.4 IU/min,依诺肝素作用下测定的CR值为8.5 IU/min,那曲肝素作用下测定的CR值为8.5 IU/min,与基线值17.6 IU/min比较差异均有统计学意义(t值分别为18.45、12.33、14.93,P＜0.01),达肝素作用下测定的CR值低于依诺肝素和那曲肝素作用下测定的CR值(t值分别为2.552、2.924,P＜0.05).结论 3种促凝剂所测得的CR值与达肝素浓度均呈指数相关关系,不同种类LMWH均可显著降低CR值.CR值有可能成为LMWH抗凝活性的床旁检测指标.

Abstract：

Objective To study the in vitro effects of different doses and different kinds of LMWH on CR, and to determine whether the CR test could be used to monitor LMWH. Methods The CR value was measured with different reagents ( glass beads, celite and kaolin ) in blood samples from twenty volunteer donors, which were spiked with increasing concentration of LMWH ( dalteparin, 0-1.8 IU/ml ). Then the CR test was performed again on the same blood samples spiked with the same concentration ( 0. 8 IU/ml ) but different LMWH ( dalteparin, enoxaparin and nadroparin ). Regression analysis was performed to establish a regression equation from corresponding LMWH levels. Results With the increasing of dalteparin dose, CR values were reduced gradually for all three reagents. When the concentration of dalteparin was 0-1.8 IU/ml,the value of CR was 20. 0-4. 5 IU/min for glass beads, 26. 1-6.6 IU/min for celite and 27. 2-7. 5 IU/min for kaolin. An exponential relationship was observed between the CR value and dalteparin concentration for three reagents( R2 = -0.796, -0.884, -0.921 ,P ＜0.01 ). All three kinds of LMWH with the same concentration (0.8 IU/ml ) induced a different change in CR. The value of CR was 7.4 IU/min with dalteparin,8. 5 IU/min with enoxaparin and 8.5 IU/min with nadroparin. Compared with the control group ( CR was 17.6 IU/min ), three kinds of LMWH had statistical significance ( t = 18.45, 12. 33, 14. 93, P ＜ 0.01 ).Compared with the enoxaparin and nadroparin, dalteparin induced a higher CR value ( t = 2. 552,2. 924,P＜0. 05 ). Conclusions There is an exponential relationship between CR value and dalteparin concentration for three reagents. Three kinds of LMWH can significantly reduce the value of CR. CR test can be used to monitor the anticoagulant effect of LMWH.     

Efficiency of oxygen delivery through different oxygen entrainment devices during sedation under low oxygen flow rate: a bench study

Sedative anesthetic procedures outside the operating room may depend on cylinders as oxygen source. Cylinders have limited storage capacity and a low oxygen flow rate improves the durability. We conducted the bench study to evaluate the fraction of inspired oxygen (FiO₂) in different oxygen entrainment devices under low oxygen flow rate. The purpose of the bench study was to provide information to choose appropriate oxygen entrainment devices in non-operating room sedative anesthetic procedures. We utilized a manikin head-test lung-ventilator model and evaluated eight oxygen entrainment devices, including four nasal cannulas, two oral bite blocks, and two masks. Two different minute volumes that defined as the normal ventilation and the hypoventilation group were evaluated. Three pneuflow resistors were placed in turn in the mouth represented ratio of the nasal/oral breathing. Each condition was sampled 70 times after a 3 min ventilation period. Most devices had few drop in FiO₂ according to the increased oral breathing ratio in normal ventilation. Most devices had obvious drop in FiO₂ related to the increased oral breathing ratio in hypoventilation. Oxygen reservoir units had little effect for accumulating oxygen in normal ventilation. In the hypoventilation group, oxygen reservoir units helped oxygen retention in local area and maintained a higher oxygen concentration. There were multiple factors lead to different oxygen fraction that we measured, such as different devices, respiratory patterns, and oxygen reservoir units. The result of our bench study provided some information for anesthesiologist to choose appropriate oxygen entrainment devices in various sedative anesthetic procedures.     

肠内营养开始时间对超低出生体重儿生长发育指标及消化功能的影响

目的探讨超低出生体重儿(ELBWI)合适的肠内营养开始时间,观察不同肠内营养开始时间对ELBWI生长发育指标及消化功能的影响。方法选择我院NICU 2013年1月-2016年5月收治的76例ELBWI,按照肠内营养开始时间,将其分为3组,A组(≤24h,26例)、B组(24~72h,25例)、C组(≥72h,25例)。观察不同的肠内营养开始时间对生长发育指标及消化功能的影响。结果 A组生后1周奶量显著高于其它两组;B组生后1周奶量显著高于C组;出生后2~3周,A组及B组奶量显著高于C组。三组患儿体质量、头围增加影响的差异无统计学意义(P0.05),但A组和C组生后1周身长增长明显高于B组;A组中心静脉置管时间小于另外两组,B组和C组差异无统计学意义(P0.05);C组达到全肠内营养的时间显著长于其它两组。结论肠内营养开始时间对ELBWI生长发育指标无影响,但早期开始肠内营养能促进其胃肠功能提前成熟,利于奶量增长,并且能缩短达到全肠内营养的时间及中心静脉置管时间。