水华蓝藻毒素研究概述

随着科技进步,发现的有毒种类越来越多,毒素分子结构的研究也越来越清楚。在大量文献的基础上,综合介绍水华微囊藻毒素、水华束丝藻毒素和水华鱼腥藻毒素对动物的毒害、毒素结构、检测方法和去除方法,并讨论存在的问题。     

腐蚀对30CrMnSiNi2A钢结构疲劳寿命的影响

采用周期浸润加速腐蚀试验与疲劳试验相结合的方法,研究了腐蚀及腐蚀与疲劳交替作用对某型飞机30CrMnSiNi2A机翼主梁疲劳寿命的影响.结果表明,腐蚀环境的影响会引起30CrMnSiNi2A高强度结构钢的疲劳寿命明显降低.与未腐蚀状态相比,预腐蚀5、10、15天后,某型飞机机翼主梁模拟件的平均疲劳寿命分别下降了17.3%、20.5%、33.2%;而在腐蚀与疲劳交替作用下,其平均疲劳寿命下降了22.8%.在给定的腐蚀环境和疲劳载荷谱作用下,平均疲劳寿命N50随预腐蚀时间t的变化可以用N50=1044.541-219.978t描述.     

直升机蒙皮典型结构有机涂层防护性能在模拟高原大气环境中的变化

目的评价服役于高原大气环境中的直升机蒙皮典型结构及其防护体系的防护性能。方法通过模拟高原大气环境加速试验方法再现直升机蒙皮典型结构防护体系实际服役过程中出现的损伤,利用扫描电镜对表面微观形貌进行观察,采用电化学阻抗谱测试研究有机涂层阻抗的变化。结果在实验室加速试验中,蒙皮试验件螺钉周边先出现局部腐蚀,之后腐蚀产物又逐渐减少,而铆钉周边经过多个周期后腐蚀产物都没有显著增多。螺钉中间区域有机涂层电化学阻抗模值直至第8个周期后与原始情况相比才大幅度下降,而铆钉中间区域有机涂层电化学阻抗模值在试验中多次明显下降。结论铆钉周边的有机涂层经过多个周期加速试验仍具有阻挡腐蚀性介质的作用。与螺钉结构的情况相比,铆钉中间区域有机涂层防护性能退化显著。     

喷丸强化对超高强度钢耐腐蚀性能的影响

目的提高舰载机结构疲劳关键部位的主体材料超高强度钢的耐蚀性能。方法基于实测的环境数据编制加速腐蚀试验环境谱,针对喷丸和未喷丸超高强度钢试验件在实验室条件下开展加速腐蚀试验,从宏观/微观形貌、质量损失、腐蚀速率和表面粗糙度等方面表征腐蚀行为,分析讨论喷丸强化对超高强度钢耐腐蚀性能的影响。结果超高强度钢腐蚀初期为局部点蚀,然后转变为全面均匀腐蚀。喷丸强化延缓了腐蚀形态转变的时机,喷丸试验件腐蚀速率约为未喷丸试验件的75%,加速腐蚀当量为3 a,未喷丸和喷丸试验件表面平均粗糙度分别为5.67mm和4.16mm,前者为后者的1.36倍。结论通过质量损失率、腐蚀速率和表面粗糙度的对比分析知,喷丸强化明显提高了超高强度钢的耐腐蚀性能。     

Surfactant-based oil dispersant toxicity to developing nauplii of Artemia: effects on ATPase enzymatic system

The paper deals with the toxicity of a surfactant-based oil dispersant to the ATPase activities of two naupliar stages of Artemia (instar I & II). Both instars were exposed to sub-lethal and lethal concentrations derived from acute toxicity data. The chosen concentrations were near to LOECs and NOECs. An eightfold difference indicated between the instars was instar-exposure time dependent. The most prominent effects were the inhibition and the stimulation of Na⁺/K⁺-ATPase and Mg²⁺-ATPase activities, respectively. The cause of these effects was related to the dispersant components, the surfactants. The pattern stimulation/inhibition of Mg²⁺-ATPase and Na⁺/K⁺-ATPase activities could be used to indicate toxic stress by surfactant-based oil dispersants since previous studies with other contaminants have shown different ATPase activity patterns.     

先进增强结构仿真分析与实验研究

目的 研究先进增强结构受载条件下的应力分布特点.方法 开展先进增强结构有限元仿真分析,模拟先进增强结构在单轴载荷作用下的应力应变特点,同时开展先进增强结构力学试验.试验以0.02 mm/s的速度匀速加载至20 kN,采用应变检测方法获取先进增强结构复合材料结构和金属基体结构的应力应变大小,对比分析有限元和试验结果.结果...     

锅炉脱硫系统烟气换热器堵塞故障分析及处理

抗滑桩在滑坡治理中应用得比较广泛,确保抗滑桩的耐久性至关重要,抗滑桩混凝土中性化程度是影响其耐久性的重要因素。通过酸雨侵蚀与应力耦合作用下的模型试验,探讨了混凝土受酸雨侵蚀后强度和中性化深度的变化情况。分析结果显示:在酸雨侵蚀作用下,抗滑桩混凝土抗压强度先增大,然后逐渐减小;应力作用下,抗滑桩混凝土中性化深度与无应力时有很大区别,弯曲拉应力作用下的混凝土中性化深度大于无应力状态下的中性化深度,弯曲压应力下的中性化深度小于无应力下的中性化深度,应力水平的大小将影响到中性化深度的大小。     

A case of mosaicism involving an unstable 13/14 Robertsonian translocation

Prenatal diagnosis of mosaicism involving an apparently unstable 13/14 Robertsonian trans-location is reported. This illustrates the difficulties encountered in counselling when mosaicism is ascertained prenatally. Other reported examples of apparently unstable Robertsonian translocations are discussed.     

Contribution of a New PCR assay to the prenatal diagnosis of congenital toxoplasmosis

A polymerase chain reaction (PCR) assay has been developed for the detection of Toxoplasma gondii. The target sequence (88 bp) is part of a rDNA repetitive gene. A signal can be observed with only one parasite. It is directly and rapidly detected by electrophoresis and ethidium bromide staining. We report a prospective study of 80 documented cases of toxoplasmic seroconversions during pregnancy. The PCR assay of the amniotic fluids was compared with the current standard methods for diagnosis of fetal infection. Seventy specimens gave no PCR signal, and were negative according to prenatal tests and postnatal examinations. The presence of T. gondii was detected in ten specimens by PCR analysis. Four were confirmed by isolation of the parasite from the amniotic fluid; four by biological study of the fetal blood. For the remaining two, infection was diagnosed after birth. Together with ultrasonographic and biological data, this technique permits prenatal diagnosis within 1 day.