期刊文献+
共找到12篇文章
< 1 >
每页显示 20 50 100
东方扁虾胚胎发育温比率的初步研究 被引量:6
1
作者 王桂忠 朱冬发 李少菁 《海洋通报》 CAS CSCD 北大核心 1998年第3期39-44,共6页
从抱卵雌虾腹部剥离的东方扁虾(Thenus orientalis Lund,1793)胚胎在四组恒温水浴(22℃±0.2℃,25℃±0.2℃,28℃±0.2℃,31℃±0.2℃)下进行的离体培养孵化实验取得成功.通过监测以胚胎眼指数来指示胚胎发育进程,建立... 从抱卵雌虾腹部剥离的东方扁虾(Thenus orientalis Lund,1793)胚胎在四组恒温水浴(22℃±0.2℃,25℃±0.2℃,28℃±0.2℃,31℃±0.2℃)下进行的离体培养孵化实验取得成功.通过监测以胚胎眼指数来指示胚胎发育进程,建立了四组温度下眼指数对时间的直线回归图。在此基础上,确立了单位时间内眼指数增长值与培养温度之间的线性关系,用于预报不同温度下胚胎的孵化日期.此外,还结合亲虾抱卵孵化实验和自然水温下离体孵化实验的结果探讨了东方扁虾胚胎孵育机制及复眼形成期发育所需要的有效积温。 展开更多
关键词 东方扁虾 胚胎 温比率 离体培养 胚胎发育
下载PDF
基于STM32的化学发光免疫分析仪温控系统的设计与应用
2
作者 李中伟 王聪 +1 位作者 吴晓磊 乔美英 《自动化应用》 2024年第4期69-72,77,共5页
在全自动化学发光免疫分析仪检测样本的过程中,温度的变化会显著影响样本与试剂化学反应的速度和结果,影响仪器检验结果的可靠性,因此,亟需高精度的温度控制系统。对此,研究了一种以STM32微处理器为核心的控制电路,选用三线制PT1000温... 在全自动化学发光免疫分析仪检测样本的过程中,温度的变化会显著影响样本与试剂化学反应的速度和结果,影响仪器检验结果的可靠性,因此,亟需高精度的温度控制系统。对此,研究了一种以STM32微处理器为核心的控制电路,选用三线制PT1000温度传感器和LTC2983数字温度测量芯片,设计了比率式测温电路,同时采用光耦驱动MOS管的方式进行驱动控制。结果表明,该温度控制电路具有较高的稳定性,且测量准确度能达到±0.1℃,满足全自动化学发光免疫分析仪上的温度要求。 展开更多
关键词 STM32 三线制PT1000 比率式测 LTC2983数字度测量芯片
下载PDF
高精度多参考阻值比率测温系统 被引量:2
3
作者 辛世杰 丁雷 《光学精密工程》 EI CAS CSCD 北大核心 2021年第5期1115-1126,共12页
单参考阻值比率测温系统是一种目前常用的高精度测温方法,可以有效削弱恒流源长期漂移、放大器增益漂移、热电势等因素对测量结果所造成的影响,但测量性能会随着测量阻值远离参考电阻阻值而变差。为了解决该问题,本文首先分析了基于恒... 单参考阻值比率测温系统是一种目前常用的高精度测温方法,可以有效削弱恒流源长期漂移、放大器增益漂移、热电势等因素对测量结果所造成的影响,但测量性能会随着测量阻值远离参考电阻阻值而变差。为了解决该问题,本文首先分析了基于恒流源的铂电阻、参考电阻比率测温方法,引入非线性因子,理论分析了测量性能会随着测量阻值远离参考电阻阻值而变差的原因,并由此提出了多参考阻值比率测温方法,进行了硬件系统的设计。对多参考阻值比率测温系统进行了长期稳定性、分辨能力、不同环境温度所造成非线性标定劣化的等效实验,验证了本文理论推导部分的正确性。实验结果表明,在-38.8~64.6℃的温度测量范围内,高精度多参考阻值比率测温系统的测量稳定性优于0.0025℃/5 day,测量分辨能力优于0.00125℃,在5~45℃环境温度下的测量稳定性优于0.004℃。基本满足长期、环境温度变化较大的温度测量应用需求。 展开更多
关键词 度测量 比率 铂电阻 多参考 非线性
下载PDF
OPTIMUM OF PRESSURE RATIOS OF MULTI-STAGE RECIPROCATING COMPRESSOR WITH PRACTICAL INTER-COOLING 被引量:1
4
作者 刘卫华 昂海松 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2002年第2期177-181,共5页
The optimum pressure ratio distribution of a multistage reciprocating compressor is presented based on the assumption, i.e. the inter stage cooling is perfect and there are no pressure losses. The optimization of the... The optimum pressure ratio distribution of a multistage reciprocating compressor is presented based on the assumption, i.e. the inter stage cooling is perfect and there are no pressure losses. The optimization of the two or three stage pressure ratio is analyzed in two cases of constant heat transfer rate for the inter cooler or constant inter stage inlet temperature, based on the minimum of the sum of theoretical compression power at each stage about a multi stage reciprocating compressor. Furthermore, with an example of two stage compressor the influence on the sum of the power of each stage is analyzed when practical pressure ratio deviates from the optimum value. It is obtained that under different cooling conditions the optimum pressure ratio distribution of the multi stage compression is various, and the change of the optimum pressure ratio within a small range has little influence on the sum of the power each stage. For the two stage compression, this range can be represented as ε 1=(0 96~1 06)ε 1j . 展开更多
关键词 inter cooler multi stage compressor pressure ratio OPTIMUM
下载PDF
Effects of temperature, salinity, and irradiance on the growth of harmful algal bloom species Phaeocystis globosa Scherffel(Prymnesiophyceae) isolated from the South China Sea 被引量:11
5
作者 徐宁 黄博珠 +3 位作者 胡章喜 唐赢中 段舜山 张成武 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2017年第3期557-565,共9页
Blooms of Phaeocystis globosa have been frequently reported in Chinese coastal waters, causing serious damage to marine ecosystems. To better understand the ecological characteristics of P. globosa in Chinese coastal ... Blooms of Phaeocystis globosa have been frequently reported in Chinese coastal waters, causing serious damage to marine ecosystems. To better understand the ecological characteristics of P. globosa in Chinese coastal waters that facilitate its rapid expansion, the effects of temperature, salinity and irradiance on the growth of P. globosa from the South China Sea were examined in the laboratory. The saturating irradiance for the growth ofP. globosa (Is) was 60 μmol/(m^2·s), which was lower than those of other harmful algal species (70-114μmol/(m^2·s)). A moderate growth rate of 0.22/d was observed at 2 μmol/(m^2·s) (the minimum irradiance in the experiment), and photo-inhibition did not occur at 230 μmol/(m^2·s) (the maximum irradiance in the experiment). Exposed to 42 different combinations of temperatures (10- 31 ℃) and salinities (10-40) under saturating irradiance, P. globosa exhibited its maximum specific growth rate of 0.80/d at the combinations of 24℃ and 35, and 27℃ and 40. The optimum growth rates (〉0.80/d) were observed at temperatures ranging from 24 to 27℃ and salinities from 35 to 40. While P. globosa was able to grow well at temperatures from 20℃ to 31℃ and salinities from 20 to 40, it could not grow at temperatures lower than 15℃ or salinities lower than 15. Factorial analysis revealed that temperature and salinity has similar influences on the growth of this species. This strain ofP. globosa not only prefers higher temperatures and higher salinity, but also possesses a flexible nutrient competing strategy, adapted to lower irradiance. Therefore, the P. globosa population from South China Sea should belong to a new ecotype. There is also a potentially high risk of blooms developing in this area throughout the year. 展开更多
关键词 Phaeocystis globosa harmful algal bloom TEMPERATURE SALINITY IRRADIANCE GROWTH
原文传递
Hydrogenation of Silicon Tetrachloride in Microwave Plasma 被引量:2
6
作者 卢振西 张伟刚 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2014年第2期227-233,共7页
This study investigated the hydrogenation of silicon tetrachloride (SIC14) in microwave plasma. A new launcher of argon (Ar) and hydrogen (Ha) plasma was introduced to produce a non-thermodynamic equilibrium act... This study investigated the hydrogenation of silicon tetrachloride (SIC14) in microwave plasma. A new launcher of argon (Ar) and hydrogen (Ha) plasma was introduced to produce a non-thermodynamic equilibrium activation plasma. The plasma state exhibited a characteristic temperature related to the equilibrium constant, which was termed "Reactive Temperature" in this study. Thus, the hydrogenation of SIC14 in the plasma could easily be handled with high conversion ratio and very high selectivity to trichlorosilane (SiHC13). The effects of SiC14/Ar and H2/Ar ratios on the conversion were also investigated using a mathematical model developed to determine the op- timum experimental parameters. The highest hydrogenation conversion ratio was produced at a H2/SiCl4 molar ratio of 1, with mixtures of SICl4 and H2 to Ar molar ratio of 1.2 to 1.4. In this plasma, the special system pressure and incident power were required for the highest energy efficiency of hydrogenating SIC14, while the optimum system pressure varies from 26.6 to 40 kPa depending on input power, and the optimum feed gas (He and SiCI4) molar en- ergy input was about 350 kJ. mo1-1. 展开更多
关键词 HYDROGENATION silicon tetrachloride non-thermodynamic equilibrium plasma equilibrium constant plasma temperature
下载PDF
Study on co-cracking performance of different hydrocarbon mixture in a steam pyrolysis furnace 被引量:9
7
作者 Benfeng Yuan Jinlong Li +1 位作者 Wenli Du Feng Qian 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第9期1252-1262,共11页
Co-cracking is a process where the mixtures of different hydrocarbon feedstocks are cracked in a steam pyrolysis furnace, and widely adopted in chemical industries. In this work, the simulations of the co-cracking of ... Co-cracking is a process where the mixtures of different hydrocarbon feedstocks are cracked in a steam pyrolysis furnace, and widely adopted in chemical industries. In this work, the simulations of the co-cracking of ethane and propane, and LPG and naphtha mixtures have been conducted, and the software packages of COILSIM1 D and Sim CO are used to account for the cracking process in a tube reactor. The effects of the mixing ratio, coil outlet temperature, and pressure on cracking performance have been discussed in detail. The co-cracking of ethane and propane mixture leads to a lower profitability than the cracking of single ethane or single propane. For naphtha, cracking with LPG leads to a higher profitability than single cracking of naphtha, and more LPG can produce a higher profitability. 展开更多
关键词 Co-cracking Mixing ratio Coil outlet temperature(COT) Coil outlet pressure(COP) Pyrolysis furnace
下载PDF
The Effect of Temperature on Growth and Energy Budget of the Polychaete,Neanthes japonica Izuka 被引量:1
8
作者 LIU Yong XIAN Weiwei 《Journal of Ocean University of China》 SCIE CAS 2009年第2期177-183,共7页
Growth and energy budget of the polychaete,Neanthes japonica,at various temperatures(17,20,23,26 and 29℃) were investigated in this study. The growth,as indicated by final dry weight and specific growth rate(SGR),inc... Growth and energy budget of the polychaete,Neanthes japonica,at various temperatures(17,20,23,26 and 29℃) were investigated in this study. The growth,as indicated by final dry weight and specific growth rate(SGR),increased with increasing temperature,with the maximum level at 26℃,and then decreased significantly at 29℃. A similar trend was observed in feeding rate,food conversion efficiency(FCE) and apparent digestive rate(ADR). However,no significant differences were detected in ADR among all the temperature treatments. In the pattern of energy allocation,faeces energy was only a small component of energy budget and had little influence on the proportion of food energy allocated to growth. The metabolic energy accounted for a large portion of energy intake for each temperature treatment. The nitrogen excretion was appreciable with changing temperature. The two expenditure terms(respiration energy and excretion energy) in energy budget were the major factors influencing the proportion of food energy allocated to growth. These results revealed that temperature affected the growth of N. japonica mainly by influencing feeding rate and FCE. In addition,regression equations describing the relationship between feeding rate,faecal production,SGR,FCE and temperature were obtained. The optimum temperatures for feeding rate,FCE and SGR were estimated at 25.01℃,24.24℃ and 24.73 ℃,respectively,from the regression equations. 展开更多
关键词 Neanthesjaponica TEMPERATURE GROWTH energy budget
下载PDF
Modeling the contribution of the microbial carbon pump to carbon sequestration in the South China Sea 被引量:4
9
作者 Wenfang LU Yawei LUO +1 位作者 Xiaohai YAN Yuwu JIANG 《Science China Earth Sciences》 SCIE EI CAS CSCD 2018年第11期1594-1604,共11页
The two key mechanisms for biologically driven carbon sequestration in oceans are the biological pump(BP) and the microbial carbon pump(MCP); the latter is scarcely simulated and quantified in the China seas. In this ... The two key mechanisms for biologically driven carbon sequestration in oceans are the biological pump(BP) and the microbial carbon pump(MCP); the latter is scarcely simulated and quantified in the China seas. In this study, we developed a coupled physical-ecosystem model with major MCP processes in the South China Sea(SCS). The model estimated a SCSaveraged MCP rate of 1.55 mg C m^(-2) d^(-1), with an MCP-to-BP ratio of 1:6.08 when considering the BP at a depth of 1000 m.Moreover, the ecosystem responses were projected in two representative global warming scenarios where the sea surface temperature increased by 2 and 4°C. The projection suggested a declined productivity associated with the increased near-surface stratification and decreased nutrient supply, which leads to a reduction in diatom biomass and consequently the suppression of the BP. However, the relative ratio of picophytoplankton increased, inducing a higher microbial activity and a nonlinear response of MCP to the increase in temperature. On average, the ratio of MCP-to-BP at a 1000-m depth increased to 1:5.95 with surface warming of 4°C, indicating the higher impact of MCP in future ocean carbon sequestration. 展开更多
关键词 South China Sea Microbial Carbon Pump Global change Numerical model
原文传递
N limitation increases along a temperate forest succession:evidences from leaf stoichiometry and nutrient resorption 被引量:5
10
作者 Peng Zhang Xiao-Tao Lu +2 位作者 Mai-He Li Tonggui Wu Guangze Jin 《Journal of Plant Ecology》 SCIE CSCD 2022年第5期1021-1035,共15页
Forest productivity and carbon(C) sequestration largely depend on soil N and P availability.To date,however,the temporal variation of nutrient limitation along forest succession is still under debate.Leaf stoichiometr... Forest productivity and carbon(C) sequestration largely depend on soil N and P availability.To date,however,the temporal variation of nutrient limitation along forest succession is still under debate.Leaf stoichiometry and nutrient resorption are important indicators for predicting nutrient limitation of plant growth.Here,we measured nitrogen(N)and phosphorus(P)concentrations in green leaves and leaf liter for all woody species at four stages of temperate forest succession,and analyzed how abiotic and biotic factors affect leaf stoichiometry and nutrient resorption along forest succession.At the individual scale,leaf N and P concentrations had a significant increase at the end of the succession,while no change in leaf N:P ratio was detected.Nitrogen resorption efficiency(NRE)increased significantly with succession,but P resorption efficiency(PRE)first increased and then decreased.Significant increases in NRE:PRE ratios only occurred at the end of the succession.Moreover,plant N cycling was less responsive to soil nutrient than P cycling.At the community scale,we found that leaf N and P concentrations first decreased and then increased along forest succession,which were mainly affected by Shannon-Wiener index and species richness.Leaf N:P ratio significantly varied with succession and was mainly determined by community-weighted mean diameter at breast height(DBH).NRE increased and was significantly influenced by species richness and DBH,while PRE was relatively stable along forest succession.Thus,the NRE:PRE ratios significantly increased,indicating that N limitation is exacerbated with the temperate forest succession.These results might reflect the intense interspecific competition for limiting resource in a higher biodiversity community.In conclusion,our findings highlight the importance of biotic factors in driving forest ecosystem nutrient cycling and provide valuable information for sustainable fertilizer management practices in China's temperate and boreal forests. 展开更多
关键词 abiotic and biotic factors forest succession N limitation N:P ratio nutrient resorption efficiency temperate forest
原文传递
Measurement of high-dynamic temperature field using high-speed quadriwave lateral shearing interferometer
11
作者 崔博川 王建立 +1 位作者 姚凯男 陈涛 《Optoelectronics Letters》 EI 2018年第2期124-128,共5页
An approach to measure a high-dynamic two-dimensional(2 D) temperature field using a high-speed quadriwave lateral shearing interferometer(QWLSI) is proposed. The detailed theoretical derivation to express the wavefro... An approach to measure a high-dynamic two-dimensional(2 D) temperature field using a high-speed quadriwave lateral shearing interferometer(QWLSI) is proposed. The detailed theoretical derivation to express the wavefront reconstruct principle of the proposed method is presented. The comparison experiment with thermocouples shows that the temperature field measurement using QWLSI has a precision of ±0.5 °C. An experiment for measuring the highdynamic temperature field generated by an electrical heater is carried out. A 200 frame rate temperature field video with 512 × 512 resolution is obtained finally. Experimental results show that the temperature field measurement system using a QWLSI has the advantage of high sensitivity and high resolution. 展开更多
关键词 Measurement of high-dynamic temperature field using high-speed quadriwave lateral shearing interferometer
原文传递
Greater soil microbial biomass loss at low frequency of N addition in an Inner Mongolia grassland 被引量:1
12
作者 Qiushi Ning Liangchao Jiang +3 位作者 Ruzhen Wang Jing Wang Xingguo Han Junjie Yang 《Journal of Plant Ecology》 SCIE CSCD 2022年第4期721-732,共12页
Soil microbial biomass is critical for biogeochemical cycling and serves as precursor for carbon(C)sequestration.The anthropogenic nitrogen(N)input has profoundly changed the pool of soil microbial biomass.However,tra... Soil microbial biomass is critical for biogeochemical cycling and serves as precursor for carbon(C)sequestration.The anthropogenic nitrogen(N)input has profoundly changed the pool of soil microbial biomass.However,traditional N deposition simulation experiments have been exclusively conducted through infrequent N addition,which may have caused biased effects on soil microbial biomass compared with those under the natural and continuous N deposition.Convincing data are still scarce about how the different N addition frequencies affect soil microbial biomass.By independently manipulating the frequencies(2 times vs.12 times N addition yr^(–1))and the rates(0–50 g N m^(−2) yr^(−1))of N addition,our study aimed to examine the response of soil microbial biomass C(MBC)to different N addition frequencies with increasing N addition rates.Soil MBC gradually decreased with increasing N addition rates under both N addition frequencies,while the soil MBC decreased more at low frequency of N addition,suggesting that traditional studies have possibly overestimated the effects of N deposition on soil microbial biomass.The greater soil microbial biomass loss with low N frequency resulted from the intensifed soil acidifcation,higher soil inorganic N,stronger soil C and N imbalance,less net primary production allocated to belowground and lower fungi to bacteria ratio.To reliably predict the effects of atmospheric N deposition on soil microbial functioning and C cycling of grassland ecosystems in future studies,it is necessary to employ both the dosage and the frequency of N addition. 展开更多
关键词 nitrogen addition frequency temperate grasslands nutrient imbalance fungi to bacteria ratio plant–microbe interaction belowground net primary production Shannon–Weiner diversity index
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部