智能电网中的电网调度技术应用研究

本文探索电网调度技术在智能电网中的应用,并通过具体案例展示其解决问题的方法和效果,分析实施后的电网调度效果包括能源稳定性、经济性和环境友好性方面的改善。针对技术应用中的关键问题和挑战,讨论了数据管理与通信安全、大规模系统优化与协调,自适应控制与动态响应能力等方面的挑战。

Investigation of the mechanical and ballistic properties of hybrid carbon/aramid woven laminates

High-performance ballistic fibers,such as aramid fiber and ultra-high-molecular-weight polyethylene(UHMWPE),are commonly used in anti-ballistic structures due to their low density,high tensile strength and high specific modulus.However,their low modulus in the thickness direction and insufficient shear strength limits their application in certain ballistic structure.In contrast,carbon fiber reinforced epoxy resin matrix composites(CFRP)have the characteristics of high modulus in the thickness direction and high shear resistance.However,carbon fibers are rarely used and applied for protection purposes.A hybridization with aramid fiber reinforced epoxy resin matrix composites(AFRP)and CFRP has the potential to improve the stiffness and the ballistic property of the typical ballistic fiber composites.The hybrid effects on the flexural property and ballistic performance of the hybrid CFRP/AFRP laminates were investigated.Through conducting mechanical property tests and ballistic tests,two sets of reliable simulation parameters for AFRP and CFRP were established using LS-DYNA software,respectively.The experimental results suggested that by increasing the content of CFRP that the flexural properties of hybrid CFRP/AFRP laminates were enhanced.The ballistic tests'results and the simulation illustrated that the specific energy absorption by the perforation method of CFRP achieved 77.7%of AFRP.When CFRP was on the striking face,the shear resistance of the laminates and the resistance force to the projectiles was promoted at the initial penetration stage.The proportion of fiber tensile failures in the AFRP layers was also enhanced with the addition of CFRP during the penetration process.These improvements resulted in the ballistic performance of hybrid CFRP/AFRP laminates was better than AFRP when the CFRP content was 20 wt%and 30 wt%.

Effects of adding sodium dichloroacetate to low-protein diets on nitrogen balance and amino acid metabolism in the portaldrained viscera and liver of pigs

Background:Identifying regulatory measures to promote glucose oxidative metabolism while simultaneously reducing amino acid oxidative metabolism is one of the foremost challenges in formulating low-protein(LP)diets designed to reduce the excretion of nitrogen-containing substances known to be potential pollutants.In this study,we investigated the effects of adding sodium dichloroacetate(DCA)to a LP diet on nitrogen balance and amino acid metabolism in the portal-drained viscera(PDV)and liver of pigs.To measure nitrogen balance,18 barrows(40±1.0 kg)were fed one of three diets(n=6 per group):18%crude protein(CP,control),13.5%CP(LP),and 13.5%CP+100 mg DCA/kg dry matter(LP-DCA).To measure amino acid metabolism in the PDV and liver,15 barrows(40±1.0 kg)were randomly assigned to one of the three diets(n=5 per group).Four essential amino acids(Lys,Met,Thr,and Trp)were added to the LP diets such that these had amino acid levels comparable to those of the control diet.Results:The LP-DCA diet reduced nitrogen excretion in pigs relative to that of pigs fed the control diet(P<0.05),without any negative effects on nitrogen retention(P>0.05).There were no differences between the control and LP-DCA groups with respect to amino acid supply to the liver and extra-hepatic tissues in pigs(P>0.05).The net release of ammonia into the portal vein and production rate of urea in the liver of pigs fed the LP-DCA diet was reduced relative to that of pigs fed the control and LP diets(P<0.05).Conclusion:The results indicated that addition of DCA to a LP diet can efficiently reduce nitrogen excretion in pigs and maximize the supply of amino acids to the liver and extra-hepatic tissues.

Correlation between special brain area and blood perfusion in patients with cerebral infarction at convalescent period Feasibility for quantitative determination and estimation of learning and memory function

BACKGROUND： Presently, clinic memory scale is used to evaluate learning memory ability in most studies, and the influence of difference in measurement condition of individuals exists. OBJECTIVE： To study the correlation between regional cerebral blood flow （rCBF） perfusion and learning memory function in special brain regions of patients with cerebral infarction at convalescent period, and to try to find out a method which can quantitatively evaluate learning ability. DESIGN： Case observation, and correlation analysis. SETTINGS： Shandong Institute for Behavioral Medicine; the Affiliated Hospital of Jining Medical College. PARTICIPANTS： Totally 70 patients with cerebral infarction admitted to Department of Neurology, Jining Medical College between January 2004 and December 2005 were involved. The involved patients, 58 male and 12 female, were averaged （52±3） years, and they were all right handed. They all met the diagnosis criteria instituted by the Fourth National Conference on Cerebrovascular Disease, and were confirmed as cerebral infarction by skull CT or MRI. Informed consents of detected items were obtained from all the patients and relatives. METHODS： When the patients were at convalescent period, their learning and memory ability were measured with “ clinic memory scale （set A）”. The 18 patients whose total mark over 100 were regarded as good learning memory function group; The 23 cases whose total mark less than 70 were regarded as poor learning memory function group. RCBF of hippocampus, nucleus amygdalae, temporal cortex and prefrontal lobe of patients between two groups were measured and compared by single photon emission computed tomography （SPECT）. The total scores of the 18 good learning memory patients and 23 poor learning memory patients were taken as dependent variable Y, and their rCBFs of hippocampus, nucleus amygdale, temporal cortex and prefrontal lobe respectively as independent variable X for linear correlation analysis. MAIN OUTCOME MEASURES： Correlation of rCBF in different brain regions and learning memory ability in patients with cerebral infarction. RESULTS： ①The rCBF of hippocampus, nucleus amygdale, temportal cortex and prefrontal cortex of good learning memory function group were significantly higher than those of poor learning memory function group （P 〈 0.05）. ②In the good learning memory function group, rCBF of hippocampus, nucleus amygdale, temportal cortex and prefrontal cortex were significantly positively correlated with memory scale scores （ r = 0.961, 0.926, 0.954, 0.907, P 〈 0.05 ） , and also in the poor learning memory function group （r = 0.979, 0.976, 0.991, 0.953, P 〈 0.05 ） . CONCLUSION： The rCBF of hippocampus, nucleus amygdale, temportal cortex and prefrontal cortex of patients with cerebral infarction are significantly positively correlated with memory scale scores. Predicting learning memory ability of patients by quantitative determination of rCBF provides a quantitative and objective method for evaluating learning memory ability.

水溶液中三氯生的吸附研究进展

三氯生(TCS)作为一种抗菌剂,在药品与个人护理产品中有着广泛的应用,已成为水环境中一种普遍存在的污染物。因其具有生物积累性、内分泌干扰效应、生殖毒性等危害,且已被证实可为某些毒性更大物质的前体,故水体中TCS的无害化处理引起了广泛关注,吸附处理法去除水中的TCS具有简单、绿色、高效等优势。文章总结了不同类型吸附剂对TCS的吸附效果,分析了水体的部分参数对吸附过程可能的影响,并对吸附过程的动力学及热力学方面进行了讨论,最后对TCS吸附处理的研究方向做出了展望。总体而言,绿色、低成本、可再生吸附剂的开发应用是研究重要方向,吸附剂的改性与复合是提高吸附效果的有效方式,为了更好地应用于实际环境中TCS的处理,TCS的吸附机理及环境因素的影响机制尚需进一步研究。

Bi-level Multi-leader Multi-follower Stackelberg Game Model for Multi-energy Retail Package Optimization

In the competitive energy market,energy retailers are facing the uncertainties of both energy price and demand,which requires them to formulate reasonable energy purchasing and selling strategies for improving their competitiveness in this market.Particularly,the attractive multi-energy retail packages are the key for retailers to increase their benefit.Therefore,combined with incentive means and price signals,five types of multi-energy retail packages such as peak-valley time-of-use(TOU)price package and day-night bundled price package are designed in this paper for retailers.The iterative interactions between retailers and end-users are modeled using a bi-level model of stochastic optimization based on multi-leader multi-follower(MLMF)Stackelberg game,in which retailers are leaders and end-users are followers.Retailers make decisions to maximize the profit considering the conditional value at risk(CVaR)while end-users optimize the satisfaction of both energy comfort and economy.Besides,a distributed algorithm is proposed to obtain the Nash equilibrium of above MLMF Stackelberg game model while the particle swarm optimization(PSO)algorithm and CPLEX solver are applied to solve the optimization model for each participant(retailer or end-user).Numeral results show that the designed retail packages can increase the overall profit of retailers,and the overall satisfaction of industrial users is the highest while that of residential users is the lowest after game interaction.

Let the sun shine into a brighter future:an interview with Prof.Aldo Steinfeld

Aldo Steinfeld(Ph.D.,University of Minnesota,1989)is a professor at the Department of Mechanical and Process Engineering of ETH Zurich,where he holds the Chair of Renewable Energy Carriers.He has pioneered the development of solar thermochemical reactor technologies for producing clean transportation fuels

Effects of special brain area regional cerebral blood flow abnormal perfusion on learning and memory function and its molecular mechanism in rats

To study the effect of special brain area regional cerebral blood flow(rCBF)abnormal perfusion on learning and memory function and its molecular mechanism,64 adult male healthy Sprague-Dawley(SD)rats were randomly divided into two groups,the false operation group(control group)and the operation group(model group).After surgical operation,the operation group undertook bilateral common carotid artery permanent ligation,while the other group did not.Learning and memory function were measured by Y-maze at 4 h,8 h,24 h and 3 d after surgical operation,respectively.The rCBF of the right frontal lobe and hippocampus was also detected by the PerifluxPF model laser Doppler flowmetry,and the expressions of c-fos or c-jun or Bcl-2 and Bax were also measured by immune histochemistry S-P method accordingly.Results showed that the rCBF of the right frontal lobe and hippocampus in the operation group was significantly lower than that in the false operation group(P,0.05).The learning indexes,error number(EN),day of reach standard and total reaction time(TRT)in the operation group,were significantly higher than that in the false operation group(P,0.05).However,the initiative evasion rate in the operation group was significantly lower than that in the false operation group.The study also found that the rCBF was relatively more,the indexes(EN,the day of reach standard and TRT)relatively fewer,but the initiative evasion rate and the memory keeping rate were relatively more.The positive expression and the average absorbency of Fos and Jun in the operation group were significantly higher than that in the false operation group(P<0.05).Furthermore,Bax and Bcl-2 positive cells were all increased over time in the operation group,and the expression ratio of Bax/Bcl-2 in the operation group was significantly higher than that in the false operation group(P<0.01).In conclusion,rCBF decrease can impair the learning and memory function in rats,which may be related to the increase of the expression ratio of c-fos or c-jun or Bcl-2 or Bax in the frontal cortex and hippocampus.

From Chinese Science Bulletin to Science Bulletin: celebrate the coming 50th birthday

As the only multidisciplinary journal supervised by Chinese Academy of Sciences and the National Natural Science Foundation of China,Science Bulletin will usher in its50th anniversary in 2016.A fifty-year history for a journal is always remarkable.However,the more important reason to celebrate besides the great age is:the fifty-year old journal continues to be vigorous and influential.

陈晓亚:能否办好期刊取决于大家的信心和努力

陈晓亚,植物生理学家,中国科学院院士、发展中国家科学院院士,中国科学院(以下简称"中科院")分子植物科学卓越创新中心/上海植物生理生态研究所研究员、博士生导师,中科院上海辰山植物科学研究中心主任,兼任上海辰山植物园园长,主要从事植物次生代谢调控及表皮细胞发育研究. 2008年起至今担任《中国科学:生命科学》编委;2014~2017年担任Science Bulletin(《科学通报》英文版)主编, 2018年起担任顾问委员会委员.

王恩哥:我与Science Bulletin

王恩哥,物理学家,中国科学院院士,第三世界科学院院士,北京大学物理学院教授,中国科学院物理研究所学术委员会主任,广东省松山湖材料实验室理事长.1999~2017年先后任中国科学院物理研究所所长、北京大学校长、中国科学院副院长.主要从事凝聚态物理研究,在纳米新材料探索及其物性、原子尺度上的表面生长动力学以及受限条件下水的全量子化复杂形态等方面做出了具有重要影响的研究工作. 2018年起担任Science Bulletin (《科学通报》英文版)主编.

Unravel the spatio-temporal patterns and their nonlinear relationship with correlates of dockless shared bikes near metro stations

The dockless bike-sharing system has rapidly expanded worldwide and has been widely used as an intermodal transport to connect with public transportation.However,higher flexibility may cause an imbalance between supply and demand during daily operation,especially around the metro stations.A stable and efficient rebalancing model requires spatio-temporal usage patterns as fundamental inputs.Therefore,understanding the spatio-temporal patterns and correlates is important for optimizing and rescheduling bike-sharing systems.This study proposed a dynamic time warping distance-based two-dimensional clustering method to quantify spatio-temporal patterns of dockless shared bikes in Wuhan and further applied the multiclass explainable boosting machine to explore the main related factors of these patterns.The results found six patterns on weekdays and four patterns on weekends.Three patterns show the imbalance of arrival and departure flow in the morning and evening peak hours,while these phenomena become less intensive on weekends.Road density,living service facility density and residential density are the top influencing factors on both weekdays and weekends,which means that the comprehensive impact of built-up environment attraction,facility suitability and riding demand leads to the different usage patterns.The nonlinear influence universally exists,and the probability of a certain pattern varies in different value ranges of variables.When the densities of living facilities and roads are moderate and the relationship between job and housing is relatively balanced,it can effectively promote the balanced usage of dockless shared bikes while maintaining high riding flow.The spatio-temporal patterns can identify the associated problems such as imbalance or lack of users,which could be mitigated by corresponding solutions.The relative importance and nonlinear effects help planners prioritize strategies and identify effective ranges on different patterns to promote the usage and efficiency of the bike-sharing system.

CEPC Technical Design Report

The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.