检索结果-南通市图书馆

Science China Chemistry 2024年第2期67卷 576-586页

作者： Xiao-bao Wu jun-Xiu shi Yi-Ming Ou Hua-Jie Jiang Yi-jun Fang Qi-Ming Wang Quan Gao Jie Yu Department of Applied Chemistry Anhui Province Engineering Laboratory for Green Pesticide Development and ApplicationAnhui Province Key Laboratory of Crop Integrated Pest ManagementAnhui Agricultural UniversityHefei230036China

A privileged strategy has been developed for the precise construction of enantioenriched azaspiro polycyclic scaffolds.Structurally diverse azaspiro polycycles bearing multiple contiguous stereocenters are obtained with excellent results(up to 99:1 e.r.,>95:5 d.r.) via sequential enantioselective four-component Ugi reactions/post-Ugi transformations with substrates containing prerequisite functional groups in the presence of anionic stereogenic-at-cobalt(Ⅲ) complexes.

关键词： asymmetric catalysis post-Ugi transformation anionic stereogenic-at-cobalt(Ⅲ)complex azaspiro polycyclic scaffold one-pot synthesis

维普期刊数据库

Survey on performance of vertical slot and nature-like fishways at Angu hydropower station, Southwest China

在线全文

学校读者我要写书评

暂无评论

Water Science and Engineering 2024年第1期17卷 83-91页

作者： jun-jian Sun Jia-yue shi Qi Zhang Xiao-tao shi jun-jun Tan PowerChina Huadong Engineering Corporation Limited Hangzhou 311122China Hubei International Science and Technology Cooperation Base of Fish Passage China Three Gorges UniversityYichang 443002China

To restore dam-blocked natural fish migratory passages,a growing number of artificial fishways have been built in water conservancy and hydropower projects in China.The Angu hydropower station involved diverse important fish habitats in the lower reaches of the Daduhe River in Southwest China.Therefore,a vertical slot fishway(VSF)and a nature-like fishway(NLF)were built near the backwater area of the reservoir to connect the upstream and downstream habitats.Hydrodynamic and aquatic ecological surveys were conducted after the completion of the project to estimate the fish passing effect of the two fishways.The results indicated that both fishways were in effective operation and could maintain the desired hydrodynamic conditions and be used by several local fish species.During the survey,149 fish from 15 species and 111 fish from 17 species were captured by the traps in the VSF and NLF,respectively,while 1263 fish from 27 species were found in the downstream area.Some species captured in the VSF were not found in the NLF,and vice versa,which implied the different preferences of fish.Meanwhile,3789 signals including 2099 upward ones and 1690 downward ones were monitored with an ultrasonic fish detector at the inlet of the VSF.These findings revealed the characteristics of fish species observed in and near the fishways and provided valuable insights into the different fish passing capabilities of VSFandNLF.

关键词： Vertical slot fishway Nature-like fishway Aguatic ecological survey Fishwaymonitoring Statistical analysis

General Method of Combining Grover and Simon for Attacking Block Ciphers

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Communications 2024年第6期21卷 237-245页

作者： Fu Xiangqun bao Wansu shi Jianhong Li Tan Henan Key Laboratory of Quantum Information and Cryptography PLA SSF IEUZhengzhou 450001China Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China

The compatibility of different quantum algorithms should be considered when these algorithms are combined.In this paper,the method of combining Grover and Simon is studied for the first time,under some preconditions or assumptions.First,we give two preconditions of applying Grover’s algorithm,which ensure that the success probability of finding the marked element is close to 1.Then,based on these two preconditions,it is found out that the success probability of the quantum algorithm for FXconstruction is far less than 1.Furthermore,we give the design method of the Oracle function,and then present the general method of combining Grover and Simon algorithm for attacking block ciphers,with success probability close to 1.

关键词： block ciphers post-quantum crypto quantum algorithms

维普期刊数据库

Distributed Optimal Formation Control for Unmanned Surface Vessels by a Regularized Game-Based Approach

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 276-278页

作者： jun shi Maojiao Ye the School of Automation Nanjing University of Science and TechnologyNanjing 210094China IEEE

Dear Editor,This letter explores optimal formation control for a network of unmanned surface vessels(USVs).By designing an individual objective function for each USV,the optimal formation problem is transformed into a noncooperative game.Under this game theoretic framework,the optimal formation is achieved by seeking the Nash equilibrium of the regularized game.A modular structure consisting of a distributed Nash equilibrium seeker and a regulator is proposed.

关键词： Regular seeking optimal

维普期刊数据库

Insights into postural orthostatic tachycardia syndrome after COVID-19 in pediatric patients

在线全文

学校读者我要写书评

暂无评论

World Journal of Pediatrics 2024年第3期20卷 201-207页

作者： Ya-Xi Cui jun-bao Du Hong-Fang Jin Department of Pediatrics Peking University First HospitalNo.1 Xi-an Men StreetWest DistrictBeijing 100034China State Key Laboratory of Vascular Homeostasis and Remodeling Peking UniversityBeijing 100191China

The pandemic caused by the novel severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)profoundly threatened human health globally and greatly impacted the world economy[1].While most patients recovered,some suff... 详细信息

关键词： acute patients tachycardia

Prevalence of prolonged grief disorder and its symptoms among bereaved individuals in China:a systematic review and meta-analysis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

General Psychiatry 2024年第2期37卷 177-188页

作者： Meng-Di Yuan jun-Fa Liu bao-Liang Zhong Research Center for Psychological and Health Sciences China University of Geosciences(Wuhan)WuhanHubeiChina Department of Psychiatry Wuhan Mental Health CentreWuhanHubeiChina

Background The prevalence of prolonged grief disorder(PGD)and its symptoms among the bereaved population in China vary considerably.Aims This meta-analysis aims to estimate the prevalence of PGD and its symptoms among bereaved individuals in China.Methods We conducted a literature search in major Chinese and English databases from their inception to 4 October 2023,for cross-sectional studies on the prevalence of PGD or its symptoms in bereaved Chinese individuals.The risk of bias of the included studies and certainty of the evidence were assessed using the Joanna Briggs Institute Critical Appraisal Checklist for Studies Reporting Prevalence Data(‘JBI checklist’)and the Grading of Recommendations,Assessment,Development and Evaluations(GRADE),respectively.The‘metaprop’package in R V.4.1.2 was used to synthesise the prevalence.Results A total of 28 studies involving 10994 bereaved individuals were included in the analysis,with JBI checklist scores between 3 and 7.The combined prevalence(95%confidence interval)of PGD and its symptoms was 8.9%(4.2%to 17.6%)and 32.4%(18.2%to 50.8%),respectively.PGD and its symptoms were most prevalent among those who had lost their only child(22.7%)and those bereaved by earthquakes(80.4%),respectively.The GRADE system assigned a very low certainty level to the evidence for the pooled prevalence of PGD and its symptoms.Conclusions The pooled prevalence of PGD and its symptoms indicate a potential high need for grief counselling services among bereaved individuals in China.This need is particularly pronounced in those who have lost their only child and those bereaved due to earthquakes.Further methodologically rigorous studies are needed to provide more accurate prevalence estimates.PROSPERO registration number CRD42023432553.

关键词： symptoms prevalence analysis

Accidental placement of venous return catheter in the superior vena cava during venovenous extracorporeal membrane oxygenation for severe pneumonia: A case report

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2024年第4期12卷 782-786页

作者： Xiao-Qin Song Yun-Long Jiang Xian-bao Zou shi-Chao Chen Ai-jun Qu Ling-Ling Guo Emergency Department Liaocheng People’s HospitalLiaocheng 252000Shandong ProvinceChina

BACKGROUND Venovenous extracorporeal membrane oxygenation(V-V ECMO)has become an important treatment for severe pneumonia,but there are various complications during the treatment.This article describes a case with severe pneumonia success-fully treated by V-V ECMO,but during treatment,the retrovenous catheter,which was supposed to be in the right internal vein,entered the superior vena cava directly in the mediastinum.The ECMO was safely withdrawn after multidiscip-linary consultation.Our experience with this case is expected to provide a reference for colleagues who will encounter similar situations.CASE SUMMARY A 64-year-old man had severe pulmonary infection and respiratory failure.He was admitted to our hospital and was given ventilation support(fraction of inspired oxygen 100%).The respiratory failure was not improved and he was treated by V-V ECMO,during which the venous return catheter,which was supposed to be in the right internal vein,entered the superior vena cava directly in the mediastinum.There was a risk of massive mediastinal bleeding if the catheter was removed directly when the ECMO was withdrawn.Finally,the patient underwent vena cava angiography+balloon attachment+ECMO with-drawal in the operating room(prepared for conversion to thoracotomy for vascular exploration and repair at any time during surgery)after multidiscip-linary consultation.ECMO was safely withdrawn,and the patient recovered and was discharged.CONCLUSION Patients may have different vascular conditions.Multidisciplinary cooperation can ensure patient safety.Our experience will provide a reference for similar cases.

关键词： Severe pneumonia Extracorporeal membrane oxygenation Complications Superior vena cava Multidisciplinary consultation Case report

Feedback of Efficient Shock Acceleration on Magnetic-field Structure Inside Young Type Ia Supernova Remnants

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第6期24卷 236-246页

作者： jun-Yu Shen Bi-Wen bao Li Zhang Department of Astronomy Key Laboratory of Astroparticle Physics of Yunnan Province Yunnan University Key Laboratory of Statistical Modeling and Data Analysis of Yunnan Province Yunnan University

Using an effective adiabatic index γeffto mimic the feedback of efficient shock acceleration, we simulate the temporal evolution of a young type Ia supernova remnant （SNR） with two different background magnetic field（BMF） topologies:a uniform and a turbulent BMF. The density distribution and magnetic-field characteristics of our benchmark SNR are studied with two-dimensional cylindrical magnetohydrodynamic simulations. When γeffis considered, we find that:（1） the two-shock structure shrinks and the downstream magnetic-field orientation is dominated by the Rayleigh–Taylor instability structures;（2） there exists more quasi-radial magnetic fields inside the shocked region; and （3） inside the intershock region, both the quasi-radial magnetic energy density and the total magnetic energy density are enhanced:in the radial direction, with γeff=1.1, they are amplified about 10–26 times more than those with γeff=5/3. While in the angular direction, the total magnetic energy densities could be amplified about 350 times more than those with γeff=5/3, and there are more grid cells within the intershock region where the magnetic energy density is amplified by a factor greater than 100.

关键词： ISM: magnetic fields ISM: supernova remnants magnetohydrodynamics (MHD) methods: numerical

Research progress of slippage characteristic and gas film stability enhancement methods on biomimetic hydrophobic surfaces

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2024年第1期36卷 87-101页

作者： Meng-zhuo Zhang Hai-bao Hu Liu-zhen Ren Lu-yao bao jun Wen Luo Xie School of Marine Science and Technology Northwestern Polytechnical UniversityXi’an710072China Research and Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen518063China

The biomimetic hydrophobic surface is a potentially efficient underwater drag reduction method and the drag reduction mechanism of this kind of surface comes from the interfacial slippage.For now,it is a hotspot to grasp the slippage characteristic and explore slippage enhancement strategies.This paper not only summarizes our numerical simulation and experimental results of slippage characteristic at the solid-liquid interface(SLI)of hydrophobic surfaces(HS)and the gas-liquid interface(GLI)of superhydrophobic surfaces(SHS)in recent years,but also introduces some innovative methods that can effectively improve the gas film stability and drag reduction effect of SHS.First,we used the molecular dynamics(MD)simulation method to figure out the effect of the solid-liquid interaction strength,the system temperature and the shear rate on the slippage of SLI,and expound their action mechanism from molecular scale.Then,by MD and multibody dissipative particle dynamics(MDPD)method,the slippage behavior at the GLI was studied under the influence of the microstructure size and the flow driving velocity.We proposed a new kind of hybrid slip boundary condition model to describe the slippage characteristic on GLI.In addition,we found through experiment that a three-dimensional backflow will appear on the GLI under the interfacial adsorption of surfactants,and the backflow direction will reverse with the change of GLI morphology.Finally,we put forward the wettability step structure and gas injection method to enhance the stability and drag reduction effect of the gas film on SHS.

关键词： Hydrophobic surface superhydrophobic surface interfacial slip underwater drag reduction

Warming intensified the effects of nitrogen addition on N_(2)O emissions from alpine meadow in the northern Qinghai-Tibet Plateau

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Climate Change Research 2024年第1期15卷 101-112页

作者： Ming-Jie LI Yi-Qing GE Hasbagan GANJURJAV Guo-Zheng HU Hong-bao WU jun YAN shi-Cheng HE Qing-Zhu GAO Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agricultural SciencesBeijing 100081China National Agricultural Experimental Station for Agricultural Environment Nagqu 852100China Ecology and Nature Conservation Institute Chinese Academy of ForestryBeijing 100091China College of Resource and Environment Anhui Science and Technology UniversityFengyang 233100China Nagqu Agriculture Animal Husbandryand Prataculture Science and Technology Research and Extension CenterNagqu 852100China Tongliao Experimental Middle School Tongliao 028000China

Warming and nitrogen(N)addition may impact soil nitrous oxide(N_(2)O)emissions,but the relationship between plant community composition and soil microbial activities remains unclear.For a two-year field study in the Qinghai-Tibet Plateau,open-top chambers were used to quantify the effects of warming,N-addition,and their interactions on N_(2)O emissions.We found that the N-addition greatly increased N_(2)O emissions by 77.4%in 2018 when compared to the control group.In contrast,warming showed little effect on N_(2)0 emissions but did increase the activity of enzymes associated with soil nitrification and denitrification.A combined effect of warming and N-addition of resulted in 208.6%(2018)and 90.8%(2019)increase in N_(2)0 emissions,respectively,compared to the individual treatments of warming or N-addition.Global warming in alpine meadows is causally linked to increased legume biomass which is further intensified with the N-addition.Intensified legume biomass(p<0.05),soil moisture(p<0.001)and enzyme activity(p<0.001)had a positive effect on N_(2)0 emissions,while diminished microbial carbon/nitrogen(MBC/MBN)(p<0.05)correlated with reduced N_(2)O emissions.Final results indicated that N-addition has a positive effect on N_(2)O emissions,and the addition of warming further intensifies this effect.The increased dominance of legumes and microbial N content contributes to this effect.These outcomes suggest that warming and atmospheric N deposition can stimulate N_(2)O emissions of alpine meadows inthefuture.

关键词： Alpine meadow Community composition Nitrogen addition Nitrous oxide flux Qinghai-Tibet Plateau Warming