Effects of gas supersaturation on lethality and avoidance responses in juvenile rock carp (Procypris rabaudi Tchang)

Laboratory experiments were conducted to determine the effects of total dissolved gas (TDG) supersaturation on acute lethality and avoidance responses in juvenile rock carp (Procypris rabaudi Tchang). The juvenile rock carp were exposed to water with different levels of supersaturation (105%, 115%, 120%, 125%, 130%, 135%, 140%, and 145%) and depth of 0.20 m at 25°C for 60 h. Median lethal time (LT50) was used to assess the lethal responses corresponding to different levels of gas supersaturation. The results show that half of the juvenile rock carp died at the 120%, 125%, 130%, 135%, 140%, and 145% levels of supersaturation, and the LT50 corresponding to different levels of supersaturation was 18.7, 15.4, 8.2, 6.6, 3.5, and 1.7 h. When the level of supersaturated water is below 115%, the mortality is negligible. Avoidance responses were observed 5 min after the fish were put into equilibrated water (99%, 0.08 m deep) and water with different supersaturated levels (105%, 115%, 125%, 135%, and 145%, 0.08 m deep) at 25 °C. The fish exhibited strong avoidance responses in supersaturated water when the gas supersaturation was above 135%. However, they exhibited an obvious preference to supersaturated water when the gas supersaturation was below 115%. Thus, the juvenile rock carp can likely survive in water with a supersaturated level of 115%.     

降低本钢烧结工序能耗的措施

本钢炼铁厂三烧360m^2烧结机在实施低硅烧结时出现了能源升高的情况,通过加强能源基础管理,挖掘节能潜力,不断提高烧结工艺技术水平和生产操作水平,减少故障时间,提高设备作业率,烧结固体燃耗、电耗、焦炉煤气消耗逐年降低,工序能耗取得了较好水平。     

北五味子叶挥发油化学成分分析

利用同时蒸馏-萃取装置提取北五味子叶挥发油,其提取率为5.05%,并用气相色谱-质谱联用仪对北五味子叶挥发油化学成分进行分析鉴定.从分离到的132个成分中,鉴定出68个成分,占挥发油总含量的53.84%,其中主要成分为1-乙烯基-1-甲基-2,4-二（丙-1-烯-2-基）环己烷（6.33%）,2,6-二甲基-6-（4-甲基-3-戊烯基）-双环[3.1.1]庚-2-烯（4.40%）和1-甲基-5-亚甲基-8-（1-甲乙基）-1,6-环癸二烯（3.98%）.     

“非常规油气地质学”研究生课程在线教学的实践与思考

"非常规油气地质学"研究生课程的在线教学实践主要体现在:提前做好预案,调整和优化教学方法;加强过程管理和痕迹管理,促进教学计划的顺利实施和教学目标的完成;充分利用网络资源,追踪非常规油气地质学的新进展,拓展教学内容;开展网络特色课堂活动,激发学生学习的积极性和主观能动性;全方位的考核方式更加注重学生在教学过程中的参与度。     

GIS在天然气长输管网中的应用

论文首先阐述了建立天然气长输管网信息系统建设的必要性和紧迫性,对系统的用户需求进行了分析,论述了系统的设计原则、目标。研究了天然气长输管网信息系统的总体设计和功能模块设计。并针对目前我国天然气长输管网数字化建设的设计、竣工等资料,以及设备信息和数字化管网运行阶段的信息特点,论述了系统数据库的内容和组织,并设计系统数据库,对管网进行完整性管理。最后论文以具体项目为研究对象,构建了天然气长输管网信息系统应用平台。系统实现了管道地理信息管理、日常生产管理,管道巡检,以及安全决策等相关功能,为各级天然气管理部门提供了实用的管理决策依据。     

基于压力传感器的气体比热容比的测定

为提高气体比热容比的测量精度,提出一种新颖的检测方法及实验检测装置。该方法通过测定物体在特定容器中的振动周期来计算气体比热容比,采用压力传感器检测气体的压力和振动周期。实验表明,该方法方便、准确,空气的比热容比测量结果为1.39。     

“固体物质中的声速最大”的说法不妥

针对一本教案中的错误和一道错误的习题,根据波速由介质决定的物理规律,引用一组声波传播速度的数据,论述"固体物质中的声速最大"的说法不妥.     

Analysis of 19-nortestosterone residue in animal tissues by ion-trap gas chromatography-tandem mass spectrometry

A rapid sample treatment procedure for the gas chromatography-tandem mass spectrometry (GC-MS) determination of 19-nortestosterone (19-NT) in animal tissues has been developed. In our optimized procedures, enzymatic hydrolysis with β-glucuronidase from Escherichia coli was performed in an acetate buffer (pH 5.2, 0.2 mol/L). Next, the homogenate was mixed with methanol and heated at 60 °C for 15 min, then placed in an ice-bath at −18 °C for 2 h. After liquid-liquid extraction with n-hexane, the analytes were subjected to a normal-phase solid phase extraction (SPE) C₁₈ cartridge for clean-up. The dried organic extracts were derivatized with heptafluorobutyric anhydride (HFBA), and then the products were injected into GC-MS. Using electron impact mass spectrometry (EI-MS) with positive chemical ionization (PCI), four diagnostic ions (m/z 666, 453, 318, and 306) were determined. A standard calibration curve over the concentration range of 1–20 ng/g was reached, with Y=467 084X-68 354 (R ²=0.999 7) for 19-NT, and the detection limit was 0.3 ng. When applied to spiked samples collected from bovine and ovine, the recoveries ranged from 63% to 101% with relative standard deviation (RSD) between 2.7% and 8.9%. The procedure is a highly efficient, sensitive, and more economical method which offers considerable potential to resolve cases of suspected nandrolone doping in husbandry animals.     

A Rare Case of Short-Chain Acyl-COA Dehydrogenase Deficiency: The Apparent Rarity of the Disorder Results in Under Diagnosis

Short-chain acyl-CoA dehydrogenase (ACAD) deficiency is an extremely rare inherited mitochondrial disorder of fat metabolism. This belongs to a group of diseases known as fatty acid oxidation disorders. Screening programmes have provided evidence that all the fatty acid oxidation disorders combined are among the most common inborn errors of metabolism. Mitochondrial beta oxidation of fatty acids is an essential energy producing pathway. It is a particularly important pathway during prolonged periods of starvation and during periods of reduced caloric intake due to gastrointestinal illness or increased energy expenditure during febrile illness. The most common presentation is an acute episode of life threatening coma and hypoglycemia induced by a period of fasting due to defective hepatic ketogenesis. Here, the case of a 4 month old female patient who had seizures since the third day of her birth and persistent hypoglycemia is described. She was born to parents of second degree consanguinity after 10 years of infertility treatment. There was history of delayed cry after birth. Metabolic screening for TSH, galactosemia, 17-OHP, G6PD, cystic fibrosis, biotinidase were normal. Tandem mass spectrometric (TMS) screening for blood amino acids, organic acids, fatty acids showed elevated butyryl carnitine (C4) as 3.40 μmol/L (normal <2.00 μmol/L), hexanoyl carnitine (C6) as 0.92 μmol/L (normal <0.72 μmol/L), C4/C3 as 2.93 μmol/L (normal <1.18 μmol/L). The child was started immediately on carnitor syrup (carnitine) 1/2 ml twice daily. Limitation of fasting stress and dietary fat was advised. Baby responded well by gaining weight and seizures were controlled. Until now, less than 25 patients have been reported worldwide. The limited number of patients diagnosed until now is due to the rarity of the disorder resulting in under diagnosis.     

城市综合体燃气设计的几点思考

城市综合体不同于传统的建筑,对各方面的要求较高,尤其对配套的燃气工程更是提出了新的课题。文章简介了城市综合体使用燃气的特点,并以实例说明了此类项目燃气设计的特点。