Antioxidant enzymes and compounds complement each other during arsenic detoxification in shoots of Isatis cappadocica Desv.

Isatis cappadocica has been reported to be an arsenic (As) hyperaccumulator. Antioxidant enzymes and compounds have been proposed to play an important role in the detoxification and tolerance of As. In the present study, As-induced oxidative stress and antioxidant responses were investigated on I. cappadocica grown hydroponically in response to application of arsenate (0–1200?μmol). As accumulation increased with an increase in arsenate concentration in the medium. Along with a significant increase in arsenate concentration, a build up in hydrogen peroxide, indicators of oxidative stress, was observed. The activity of superoxide dismutase and peroxidase was induced after arsenate treatment, reached a maximal value at 800?μmol arsenate and then declined at the highest arsenate treatment. Glutathione reductase activity and contents of non-enzymatic antioxidants (carotenoids, flavonoids and anthocyanins) increased significantly as arsenate concentration augmented. These results indicated that high efficient antioxidant system may play significant roles in As detoxification and improve I. cappadocica tolerance against As toxicity.     

热盐腐蚀环境对TC11钛合金高温寿命影响规律试验研究

目的 针对发动机钛合金部件在热盐环境与工作载荷下的寿命衰减问题，开展TC11钛合金热盐腐蚀疲劳与应力腐蚀试验，研究腐蚀环境下TC11的高温寿命衰减规律与失效机理。方法 利用喷盐法制备TC11钛合金试验件，研究不同温度与应力水平对TC11腐蚀疲劳以及应力腐蚀的影响规律。利用SEM等观测手段，开展腐蚀疲劳以及应力腐蚀试样断口与表面的形貌分析，分析腐蚀环境下的失效机理。结果 热盐腐蚀环境导致TC11的寿命显著降低，对比450 ℃下无腐蚀寿命，腐蚀疲劳寿命下降了2个数量级，应力腐蚀寿命下降到不足1%，且分散性较大。观察腐蚀疲劳和应力腐蚀的试样可以发现，表面有明显的腐蚀坑，腐蚀坑底发现裂纹。结论 热盐环境下，TC11腐蚀疲劳寿命和应力腐蚀寿命都会明显下降。由于腐蚀导致钛合金试样表面产生许多腐蚀坑，在腐蚀坑局部形成近似缺口，缺口部位的应力集中是导致腐蚀疲劳寿命衰减的重要因素。腐蚀疲劳的寿命低于Kt=1的无腐蚀疲劳寿命，但是要大于Kt=3的无腐蚀疲劳寿命。     

视屏显示终端对精神心理和神经行为的影响

本文进行了视屏显示终端(VDT)对操作人员精神心理和神经行为影响的调查研究。初步显示VDT作业可对操作人员造成情绪、感知、记忆、操作及复合功能诸多方面的不良影响。通过职业应激源的调查评价,显示VDT作业本身独特的作业性质、环境和要求形成了VDT作业的主要应激源。对从事VDT作业时间较长和作业负荷较大者则产生较高的职业性紧张度。从而说明VDT作业引起操作人员的某些心身疾患的可能性。     

AQUATIC ORGANISMS RESPONSE TO SEVERE STRESS FOLLOWING ACUTELY SUBLETHAL TOXICANT EXPOSURE1

ABSTRACT: Snails, Goniobasis livescens (Menke), were exposed to acutely sublethal concentrations of p-nitrophenol and the lampricide, 3-triflourmethyl-4 nitrophenol(TFM), and then to acutely lethal thermal shocks. The same species were also exposed to acutely sublethal concentrations of zinc followed by exposure to acutely lethal concentrations of p-nitrophenol; and to acutely sublethal concentrations of TFM followed by exposure to acutely lethal concentrations of zinc. Brown trout, Salmo trutta, were exposed to acutely sublethal concentrations of TFM and then to an acutely lethal thermal shock. Results of these experiments indicate that prior exposure to acutely sublethal toxicant concentrations may reduce survival time for a subsequent exposure to acutely lethal concentrations of a second toxicant (e.g., snails exposed to Zn⁺⁺ then p-nitrophenol) but neither prior or concomitant exposure to acutely sublethal toxicant concentrations insures that the median survival time for a lethal exposure will be significantly altered (e.g., snails exposed to 0.2 × 48 hour LC50 for TFM then Zn⁺⁺). However, some acutely sublethal concentrations of a toxicant may significantly alter survival time of snails to a lethal concentration of a different toxicant (e.g., exposure to 0.4 × 48 hour LC50 TFM then a lethal dose of Zn⁺⁺). The brown trout exposed to an acutely sublethal concentration of TFM and then an acutely lethal thermal shock did have significantly altered survival patterns.     

基于力电耦合冲击矿压电磁辐射预测法的研究

笔者首先提出了煤岩变形破裂过程电磁辐射与应力耦合的概念 ,然后在实验研究、理论分析和数值模拟的基础上从力电耦合的角度研究了煤岩冲击矿压预测的电磁辐射法 (EME)。研究结果表明 :FLAC3D方法能对矿山巷道掘进过程煤岩内部应力场进行有效的数值模拟 ;电磁辐射信号主要来源于应力集中区 ,在场点监测到的电磁辐射信号主要是应力集中区煤岩变形破裂过程产生的 ;EME信号呈现出与煤岩内部应力变化相同的规律 ;利用力电耦合方法研究煤岩冲击矿压电磁辐射预测法是可行的。笔者最后还对未来煤岩冲击矿压电磁辐射预测法的研究进行了展望。     

Recycling and utilization of metabolic wastes for energy production is an index of biochemical adaptation of fish under environmental pollution stress

The activity levels of lactate dehydrogenase andlactic acid were assessed in various tissues of the fishduring exposure to lethal concentration of group-IIPyrethroids (deltamethrin, cypermethrin, fenvalerate andfluvalinate) for a period of 72 hours. The results showedsteady increased levels in all the tissues (blood,muscle, brain and liver) with response patterncharacteristic of their own. The increased LDH activityand lactic acid levels indicate the shifting of aerobicglycolysis to anaerobiosis and its further utilizationfor energy production during adaptation to toxic stress.     

Effects of mechanical fracturing and experimental trampling on Hawaiian corals

In situ trampling occurred under experimental conditions to quantify the differences in the responses to anthropogenic trampling in four dominant species of Hawaiian corals, Porites compressa, Porites lobata, Montipora capitata, and Pocillopora meandrina. Trampling was simulated daily for a period of nine days at which time further breakage was minimal. Forty treatment colonies produced 559 fragments. Trampling was followed by an 11-month recovery period. Coral colony and fragment mortality was low. All four species were highly tolerant of inflicted damage, suggesting that some species of corals can withstand limited pulse events that allow time for recovery. Growth rates following trampling were significantly lower in the treatment groups for three of the four species. This study demonstrated that very few trampling events can produce significant changes in growth even after a long recovery period. Survivorship of fragments is clearly size- and species-dependent in M. capitata and P. compressa. Smaller fragments (<5 cm) had higher mortality than larger fragments (>5 cm). High breakage rates for M. capitata and P. compressa are consistent with the nearshore, low-energy regions they inhabit—the same environment frequented by skin divers and waders. Mechanical tests were conducted to determine tensile and compressive strengths. Pocillopora meandrina exhibited the strongest skeletal strength, followed in decreasing order by Porites lobata, Porites compressa, and Montipora capitata. The skeletal strength obtained from the experiments correlate with the wave energy present in the environments in the regions they inhabit, suggesting that structural strength of corals is an adaptive response to hydraulic stress.     

高等职业技术教育的模式比较

本文分析了我国蓬勃发展的高职教育形势,对国内外主要职业教育的培养模式进行了比较,以期为我国高等职业技术教育的健康发展提供帮助。     

地应力壶与临震预测

设计和安装了地应力壶，在１９７７～１９７８年进行了观测。用日变曲线异常进行临震预测。在地震三要素预测中，发震时间预测较准确；在地点上震中方位角预测较准，震中距难以预测；震级预测误差较大。     

高压容器旋转自紧方法研究

把超速旋转工艺引入高压容器自紧过程，提出旋转自紧方法，并对平面应变问题导出了厚壁圆管在旋转时的弹塑性及塑性极限的应力解和停转后的残余应力解，所得结果表明，由于残余应力的存在而导致了圆管弹性强度极限的提高，达到了自紧的效果。