共查询到18条相似文献，搜索用时 125 毫秒
1.
Extraction and physicochemical characteristics of a red pigment produced by marine bacterium strain S-9801 总被引：2，自引：0，他引：2
A red pigment that has better biological properties is produced by marine bacterium strainS- 9801. The extraction methods, physicochemical and toxicity of the pigment have been studied. Dissolubility of pigment in the five organic solvent has been tested, and ethanol is optimally chosen for extraction. Physicochemical characteristics of this pigment was stable. The absorbance of the pigment solution was no losing when put under natural light for 10 days or treated by UV for 30 minutes, color of the pigment unchanged after 100 ℃ hythere for 1 h or 80 ℃ xerother for 2 h. The median lethal dose (LD_(50) )of the rat by celiac injection was 670.04 mg/kg and minimum lethal dose of oral was greater than 2 000 mg/kg. 相似文献
2.
The topside floatover installation is always a great challenge and is sensitive to environmental conditions.In this study,experimental analysis on the mating operation of the floatover installation in different wave headings is presented.The continuous mating operation using the rapid transfer technique was experimentally simulated with the assistance of the jacking system and the ballast system.In the continuous transfer modeling,the topsides loads were transferred onto the jacket by several consecutive steps,including the first rapid jack-down for the 30%loads,continuous 30%?70%load transfer and the second repaid jack-down for the remaining 30%loads.Motions of the barge and the topsides as well as loads on the Deck Support Unite(DSU)and the Leg Mating Unite(LMU)in different wave headings were measured.Experimental results illustrated the complex motion behavior and load characteristics of the continuous transfer operation.Results indicate that the rapid jack-down operations will lead to impact loads and larger lateral DSU loads.The bow quartering seas are much more dangerous as it gives rise to the larger motions and loads.Comparisons with the traditional steady-state modeling indicate that the continuous transfer modeling has greater advantages over the steady-state modeling on predicting the loads. 相似文献
3.
Abstract-The growth rate of the hyalid amphipod Hyale perieri was studied on the bases of Ikeda'sgrowth model which is based on the inter moult period (IP) and moult increament (ΔBL). To applythis approach, laboratory experiments were carried out at three temperatures regimes (15℃, 20℃,25℃) to gain accurate data of IP and BL. The total number of specimens used in this study was 86 at15℃, 24 at 20℃ and 70 at 25℃. The number of flagellar segments of both antennae of the Hyaleperieri could not be used as an index of growth (instar criterion). The obtained results indicated that,the predicted IP of the specimens was inversely related to temperature and in good agreement with theobserved values at the experimental temperatures. IP data obtained from laboratory-reared specimes arecombined with ΔBL data to establish a growth model for Hyale perieri from its release from the mar-supium (1.64 mm BL) to the maximum size (12.67 mm BL) as a function of temperature. The maxi-mum numbers of consecutive moults 相似文献
4.
As a key species of the Southern Ocean ecosystem,the thermal and saline tolerances of Antarctic krill(Euphausia superb a Dana)are relatively unknown because of the challenging environment and complicated situations needed for observation have inhibited in-situ experiments in the field.Hence,the thermal and saline tolerance of krill were examined under in-situ aquarium conditions with different controlled scenarios.According to the experiments,the critical lethal times of krill were 24h,2h and 0.5h under 9℃,12℃,and 15℃,respectively,and the estimated 50%lethal times were about 17.1 h and 1.7 h under 12℃and 15℃,respectively.Additionally,the critical lethal times(the estimated 50%lethal times)of krill were approximately 14h and 0.5h(about 22.9 h and 1.7 h)of salinity under 19.7 and 15.9,respectively.The observed critical and 50%lethal times of krill were 0.5 h and approximately 1.4 h,respectively,salinity under 55.2.The critical and 50%lethal temperatures of krill were 13℃and approximately 14.2℃,respectively.Additionally,the critical and 50%lethal salinity was 19.6 and approximately 17.5 for the lower saline(below normal oceanic salinity[34.4])environment and 50.3 and approximately 53.2 for the higher saline(above 34.4)environment,respectively.The upper thermal and saline preferences of krill can be considered 6℃and 26.8 to 41.2,respectively.These results can provide potential scenarios for predicting the possible fate of this key species in the Southern Ocean. 相似文献
5.
Enzymatic properties of UFE, a novel marine fibrinolytic enzyme 总被引：2，自引：0，他引：2
A novel potent protease, Urechis unicinctus fibrinolytic enzyme (UFE), was firstly discovered. The enzymatic properties of UFE were further investigated. As a low molecular mass protein, UFE appeared to be very stable to heat and pH. When temperature was below 50 ℃, the remnant enzyme activity remained almost unchanged, but when temperature was raised to 60 ℃, the remnant enzyme activity began to decrease rapidly. UFE was quite stable in the range of pH value from 3 to 12, especially in slightly alkaline pH value. Mn2 , Cu2 and Fe2 ions were activators of UFE, while Fe3 and Ag ions were inhibitors of UFE. Fe2 ion along with Fe3 ion might regulate UFE activity in vivo. The optimum pH and temperature of UFE were about 8 and 50 ℃, respectively. Other characteristics of this enzyme were also studied. Systematic research results are significant when UFE is applied for medical and industrial purposes. 相似文献
6.
In this study,the authors investigated the effects of residual chlorine on mortality,grazing and respiration of Labidocera euchaeta in laboratory.The grazing rate was evaluated by subtraction method of food concentration and respiration rate was measured using oxygen electrode.It was found that the lethal effect of residual chlorine on L.euchaeta increased with enhanced concentration and prolonged duration.The medium lethal concentration (LC 50 ) of chlorine for L.euchaeta in 24 h was about 0.58 mg/L and the safe concentration was about 0.21 mg/L.However,the grazing and respiration of L.euchaeta decreased by 32.6% and 18.9% when exposed to 0.2 mg/L residual chlorine for 4 h.It indicated that the physiological activities of zooplankton could be suppressed by the residual chlorine less than the safety concentration.Therefore,both survival and physiological activities of the organisms living in the thermal (nuclear) power plant discharging waters should be considered when carrying out the ecological risks assessment. 相似文献
7.
HY-2A is the first one of the Chinese HY-2 ocean satellite series carrying a microwave radiometer(RM)to measure sea surface temperature,sea surface wind speed,atmospheric water vapor,cloud liquid water content,and rain rate.We verified the RM level 1B brightness temperature(T B)to retrieve environmental parameters.In the verification,TB that simulated using the ocean-atmosphere radiative transfer model(RTM)was used as a reference.The total bias and total standard deviation(SD)of the RM level 1B TB,with reference to the RTM simulation,ranged-20.6-4.38 K and 0.7-2.93 K,respectively.We found that both the total bias and the total SD depend on the frequency and polarization,although the values for ascending and descending passes are different.In addition,substantial seasonal variation of the bias was found at all channels.The verification results indicate the RM has some problems regarding calibration,e.g.,correction of antenna spillover and antenna physical emission,especially for the 18.7-GHz channel.Based on error analyses,a statistical recalibration algorithm was designed and recalibration was performed for the RM level 1B TB.Validation of the recalibrated TB indicated that the quality of the recalibrated RM level 1B TB was improved significantly.The bias of the recalibrated T B at all channels was reduced to<0.4 K,seasonal variation was almost eradicated,and SD was diminished(i.e.,the SD of the 18.7-GHz channel was reduced by more than 0.5K). 相似文献
8.
Subtropical sediment cores(QA09-1 and QA12-9) from the coastal zone of Qi'ao Island in the Zhujiang River Estuary were used to determine the rates of sulfate reduction and their response to experimental temperature changes. The depth distribution of the sulfate reduction rates was measured from whole-core incubations with radioactive tracer 35SO42-, and peaks of 181.19 nmol/(cm3·d) and 107.49 nmol/(cm3·d) were exhibited at stations QA09-1 and QA12-9, respectively. The profiles of the pore water methane and sulfate concentrations demonstrated that anaerobic oxidation of methane occurred in the study area, which resulted in an increase in the sulfate reduction rate at the base of the sulfate-reducing zone. Meanwhile, the sulfate concentration was not a major limiting factor for controlling the rates of sulfate reduction. In addition, the incubation of the sediment slurries in a block with a temperature gradient showed that the optimum temperature for the sulfate reduction reaction was 36℃. The Arrhenius plot was linear from the lowest temperature to the optimum temperature, and the activation energy was at the lower end of the range of previously reported values. The results suggested that the ambient temperature regime of marine environments probably selected for the microbial population with the best-suited physiology for the respective environment. 相似文献
9.
Song Yupu Zhao Guofan
Ph. D. Professor The State Key Laboratory of Coastal Offshore Engineering Dalian University of Technology Dalian Professor 《中国海洋工程》1994,(2)
-The temperature distributions obtained by different methods of analysis for solving thermal transfer of reinforced concrete (R. C.) submarine oil tanks (RCSOT), including flat wall method, cylinder wall method and finite element method, are compared with the experimental data of thermal transfer of RCSOT. The precision and scope of applicability of different methods are discussed. The principle for selecting analysis method for solving thermal transfer of RCSOT is given. The analytical and experimental temperature distributions show that the wall of RCSOT should consist of double walls and empty space between them should be filled with sand or other heat insulation materials to reduce the temperature difference of the wall and to prevent concrete from cracking. 相似文献
10.
The natural gas generation process is simulated by heating source rocks of the Yacheng Formation, including the onshore-offshore mudstone and coal with kerogens of Type II_2-III in the Qiongdongnan Basin. The aim is to quantify the natural gas generation from the Yacheng Formation and to evaluate the geological prediction and kinetic parameters using an optimization procedure based on the basin modeling of the shallow-water area. For this, the hydrocarbons produced have been grouped into four classes(C_1, C_2, C_3 and C_(4-6)). The results show that the onset temperature of methane generation is predicted to occur at 110℃ during the thermal history of sediments since 5.3 Ma by using data extrapolation. The hydrocarbon potential for ethane, propane and heavy gaseous hydrocarbons(C_(4-6)) is found to be almost exhausted at geological temperature of 200℃ when the transformation ratio(TR) is over 0.8, but for which methane is determined to be about 0.5 in the shallow-water area. In contrast, the end temperature of the methane generation in the deep-water area was over 300℃ with a TR over 0.8. It plays an important role in the natural gas exploration of the deep-water basin and other basins in the broad ocean areas of China. Therefore, the natural gas exploration for the deep-water area in the Qiongdongnan Basin shall first aim at the structural traps in the Ledong, Lingshui and Beijiao sags, and in the forward direction of the structure around the sags, and then gradually develop toward the non-structural trap in the deep-water area basin of the broad ocean areas of China. 相似文献
11.
滨海电厂温排水停止排放以及季节更替、寒潮来袭等现象会引起海水温度降低,从而对鱼类等变温生物产生冷冲击效应。本研究通过模拟水温骤降情形,以孵化率、死亡率、畸形率等为指标,探讨了温度骤降对大黄鱼早期发育阶段(鱼卵和仔鱼)的冷冲击作用。研究发现,大黄鱼仔鱼(3日龄)对温度骤降的敏感性略高于鱼卵。在大黄鱼鱼卵和仔鱼的适温范围内,当水温由22 ℃骤降至19 ℃或16 ℃时,鱼卵的孵化率和死亡率无明显变化,而胚胎发育和仔鱼的生长发育均减缓,仔鱼的死亡率提高;水温超出适温范围,由22 ℃骤降至13 ℃或10 ℃时,对鱼卵和仔鱼造成致命的冷冲击伤害,48 h累积死亡率分别为84.6%~100%和72.1%~98.2%。由此推测:当水温骤降超出适温范围后,大黄鱼的早期发育阶段遭受致命的冷冲击伤害,从而影响种群补充和年龄结构。 相似文献
12.
在冰脊的固结过程中,由于接触面积与温差的大幅提升,冰水之间的换热强度显著增强。本文通过浸没试验对自然对流条件下冰水间的换热系数进行了研究。在试验过程中,对试样内部的温度分布与体积变化分别用温度梯度测试系统与数字图像进行测量。为研究初始条件对换热系数的影响,分别采用不同初始温度与厚度的试样在瞬态热传导的环境下进行测试。试验结果表明,换热系数与表面温差呈指数增长,且在本文试验条件下的变化区间为0.3~175 W/（m2·K）。试样的初始温度及厚度并不是影响换热系数的直接因素,而其根本因素为流-固界面的边界层状态。在自然对流状态下流体的驱动条件是热胀效应,即当边界层存在温度差时,虽然外界并不存在扰动流体状态的因素,但由于液体自身温差引起的密度差进而驱动流体运动并影响了换热系数。随着边界层温度梯度的增加,边界层的影响区域扩大,从而导致了较高的换热系数。 相似文献
13.
2008年孟加拉湾春季暖池生消过程的热收支诊断分析 总被引：1，自引：1，他引：0
在夏季风爆发前孟加拉湾会出现季节性暖池,在季风爆发后它则快速消失。本文利用RAMA浮标阵列中孟加拉湾中部浮标的观测资料,通过进行混合层热收支诊断,对2008年孟加拉湾春季暖池的生消过程进行了分析。结果表明:热通量项主导了暖池的生成和消亡过程,它在暖池生成期表现为强加热效应,而在暖池消亡期变为强冷却效应;垂向卷夹的冷却作用在暖池生成阶段比较突出;温度平流项的冷却作用在冬季较强。对热通量项的进一步分析表明:短波辐射平均热效应在暖池生成期高达0.32℃/d,而在暖池消亡期降低一半,这是使热通量项在两个时期有不同表现的根本原因;潜热通量在各阶段的平均冷却效应基本保持不变,都在-0.14℃/d左右;长波辐射的冷却效应在暖池生成期比较显著,一定程度上减缓了海温的上升速度;感热通量的热效应相对较小。 相似文献
14.
三疣梭子蟹(Portunus trituberculatus)幼体不同干露温度下死亡率的研究 总被引：1，自引：0，他引：1
通过设置15℃、20℃、25℃、30℃4个干露温度梯度,检测不同发育阶段三疣梭子蟹幼体的露空时间、死亡率、含水量、失水率及体重消耗率等指标,分析干露温度、发育阶段与幼体死亡率的关系。结果表明,各发育阶段的幼体死亡率均随干露时间的增加而升高(P<0.05);不同温度条件下,Ⅰ期幼蟹(CⅠ)的含水量、失水率和体重消耗率均高于Ⅱ期幼蟹(CⅡ)(P<0.05);CⅡ20℃时的露空时间最长,为11h,半致死时间为7—8h;30℃时最短,为2h;CⅠ15℃时的露空时间最短,为0.5h;20℃时最长,为4h。相同温度下,幼体各发育阶段的耐干露能力为CⅡ>CⅠ>ZⅣ>ZⅢ=M。结果说明,温度≤15℃不利于幼体的存活,温度≥25℃干露耐受性降低。因此,20℃更有利于幼体获得长存活时间。 相似文献
15.
温度操作对褐牙鲆幼鱼的生长和能量分配的影响 总被引：1，自引：0，他引：1
实验对褐牙鲆(Paralichthys olivaceus)幼鱼在温度胁迫及温度调整后的生长与能量分配进行了研究。驯养于17.5℃的褐牙鲆幼鱼分别在8.5℃(T8.5),13.0℃(T13.0),17.5℃(T17.5),22.0℃(T22.0)和26.5℃(T26.5)养殖10 d后,除T22.0处理的褐牙鲆幼鱼除以干重表示时与T17.5和T26.5处理差异不显著外,以湿重、蛋白质和能量表示的鱼体重均显著大于其他处理。所有处理调整养殖温度至22.0℃继续养殖,由于不同温度造成的生长差异在30 d内可获得完全补偿。在不同温度养殖期间,摄食量少和分配于生长的能量减少是导致低温处理(T8.5和T13.0)生长慢的主要原因,而T17.5和T26.5生长慢的主要原因是分配在生长的能量较少。低温处理分配于生长的能量较少主要是由于其粪便损失和用于呼吸的能量比例较多,而高温处理则主要是由于排泄损失的能量比例较高导致生长能减少。温度调整后的第2个10 d,T8.5,T13.0,T17.5和T26.5的摄食量都显著比T22.0多,而温度调整后的30 d内不同处理的总摄食量没有显著差异,个体水平上的摄食能在生长、粪便、排泄、呼吸上的分配也没有显著差异。因此,补偿生长的获得主要依靠阶段性的提高摄食量。在温度调整后的30 d内,T8.5,T13.0,T17.5和T26.5的幼鱼单位体重日摄食能和生长能都比T22.0多,表现出明显的补偿生长现象。对于整个实验期间而言,T8.5的幼鱼摄食比其他处理少,但由于其排泄和呼吸损失的能量比例较少,因此分配于生长的能量比例比其他处理略多。养殖在不同温度的褐牙鲆幼鱼会在身体蛋白质和能量含量上产生差异,在实验结束时T8.5和T26.5的能量含量与对照组仍有显著差异。本研究的结果表明褐牙鲆幼鱼对温度变动具有较强的适应能力,短期的温度变动不会对其长期生长产生显著影响。 相似文献
16.
雪热传导系数是海冰质量平衡过程中的重要物理参数,决定了穿透海冰的热传导通量。北冰洋海冰质量平衡浮标观测获得多年冰上冬季温度链剖面可以明显地区分冰雪界面。本文考虑到冰雪界面处温度随时间变化,再根据冰雪界面热传导通量连续假定,提出了新的雪热传导系数计算方法。受不同环境因素影响,多年冰上各个浮标的雪热传导系数在0.23~0.41 W/（m·K）之间,均值为（0.32±0.08） W/（m·K）。北冰洋多年冰上冬季穿过海冰的热传导通量最大发生在11月至翌年3月,约14~16 W/m2。结冰季节,来自海冰自身降温的热量对穿过海冰向大气传输的热量贡献逐月减少,从9月100%减小到12月的35%,翌年的1月至3月稳定在10%左右。夏季,短波辐射通能量通过热传导自上而下加热海冰,海冰上层温度高于下层,热量传播方向与冬季反向,往海冰内部传递。直到9月短波辐射完全消失,气温下降,热量再次转变为自下往上传递。从冰底热传导来看,夏季出现海冰向冰水界面传递热量现象。由于雪较好的绝热性,冰上覆雪极大地削弱了海冰上层热传导通量,从而减缓了秋冬季节的结冰速度。尽管受雪厚影响,多年冰上层热传导通量与气温依旧具有很好的线性关系,气温每降低1℃,热传导通量增加约0.59 W/m2。 相似文献
17.
Temperature and light tolerance of representative brown, green and red algae in tumble culture revealed by chlorophyll fluorescence measurements 总被引：2，自引：0，他引：2
Laminaria japonica, Undaria pinnatifida, Ulva lactuca, Grateloupia turuturu and Palmaria palmata are suitable species that fit the requirements of a seaweed-animal integrated aquaculture system in terms of their viable biomass, rapid growth and promising nutrient uptake rates. In this investigation, the responses of the optimal chlorophyll fluorescence yield of the five algal species in tumble culture were assessed at a temperature range of 10 - 30℃. The results revealed that Ulva lactuca was the most resistant species to high temperature, withstanding 30℃ for 4 h without apparent decline in the optimal chlorophyll fluorescence yield . While the arctic alga Palmaria palmata was the most vulnerable one, showing significant decline in the optimal chlorophyll fluorescence yield at 25℃ for 2 h. The cold-water species Laminaria japonica, however, demonstrated strong ability to cope with higher temperature （24 -26℃ ） for shorter time （within 24 h） without significant decline in the optimal chlorophyll fluorescence yield . Grateloupia turuturu showed a general decrease in the optimal chlorophyll fluorescence yield with the rising temperature from 23 to 30℃ , similar to the temperate kelp Undaria pinnatifida. Changes of chlorophyll fluorescence yields of these algae were characterized differently indicating the existence of species-unique strategy to cope with high light. Measurements of the optimal chlorophyll fluorescence yield after short exposure to direct solar irradiance revealed how long these exposures could be without significant photoinhibition or with promising recovery in photosynthetic activities. Seasonal pattern of alternation of algal species in tank culture in the Northern Hemisphere at the latitude of 36°N was proposed according to these basic measurements. 相似文献
18.
双齿围沙蚕对潮汐更替的行为响应 总被引：1，自引：0，他引：1
潮汐更替对潮间带生物的生理和行为影响显著,底内动物可以通过行为过程建立适宜的微环境适应潮间带环境变化。本实验运用行为学观测装置研究了双齿围沙蚕对潮汐更替的行为响应特征。实验设置3个温度梯度（15℃、20℃和25℃）和4个时间段（T1: 退潮前、T2: 退潮后、T3: 涨潮30 min内和T4: 涨潮30 min后）,每个处理组设6个重复。结果显示,在同一时间段内,随着温度的升高,双齿围沙蚕的径向起伏频率、径向起伏泵水速率、轴向爬行速度和头尾对调次数呈增大的趋势,头尾对调一次的时间逐渐缩短。同一温度下,双齿围沙蚕在T3时间段内的径向起伏频率、轴向爬行速度、径向起伏泵水速率、径向起伏泵水效率、轴向爬行时间和头尾对调次数均高于其他时间段,头尾对调一次的时间均有短于其他时间段的趋势;T1和T4时间段内的所有运动指标均无显著差异（p>0.05）。20℃时,双齿围沙蚕在T3时间段比T1时间段的径向起伏频率和泵水速率的增幅均高于15℃和25℃时。同一时间段内,双齿围沙蚕径向起伏时间的最大值和轴向爬行时间的最小值均出现在20℃。15℃和20℃时,双齿围沙蚕在T1和T3时间段内的轴向爬行速度均无显著差异（p>0.05）。但是在25℃时,T3时间段内双齿围沙蚕的轴向爬行速度显著高于T1时间段（p<0.05）。结果表明,双齿围沙蚕的运动强度随温度升高而增强,在水温为20℃时,其在沉积物中的运动状态较佳。退潮后双齿围沙蚕轴向爬行运动较为缓慢;刚涨潮时,双齿围沙蚕的运动强度显著增加;涨潮30 min后,双齿围沙蚕的运动逐渐恢复到与退潮前相近的状态。双齿围沙蚕可以通过一系列运动行为应对潮汐更替产生的不利条件。 相似文献