重庆大学学生核学会组织核科学知识培训

2023年1月13日,《大学科普》编辑部、全国科学技术名词审定委员会、重庆大学核工程与核技术系、重庆大学学生核学会联合,通过在线报告和交流的方式顺利举办了“核科学技术名词专题学习暨科技志愿者研学班(第一期)”研习活动。本次参加研学班的学员有重庆大学核工程与核技术系、重庆大学学生核学会、重庆市大学科学传播研究会、重庆市涪陵实验中学校、重庆市涪陵第五中学校、重庆市渝西中学、重庆量子时空教育科技有限公司、重庆市九龙坡区科普创作与传播学会、兰州大学核科学与技术学院、西北工业大学动力与能源学院、清华人文学院、陕西师范大学等的师生、员工。

CFRP复合材料超声振动套孔分层抑制机理分析

针对碳纤维增强复合材料在传统钻孔过程易出现分层缺陷,采用金刚石空心套刀和超声振动加工技术进行了CFRP超声振动套孔分层抑制机理分析。理论分析了传统麻花钻钻孔与金刚石套刀普通套孔过程的分层机理及评价,超声振动套孔对分层抑制的机理,并且进行了实验验证。结果表明:相比于CFRP普通套孔,超声振动套孔能够有效提高套刀切削性能和排屑效果,降低钻削力12.5%~19.2%,抑制切屑粉尘黏附套刀和料芯堵塞套刀,抑制CFRP分层缺陷形成,改善孔表面质量。

A Quasi-Interpolation Satisfying Quadratic Polynomial Reproduction with Radial Basis Functions

In this paper,a new quasi-interpolation with radial basis functions which satis- fies quadratic polynomial reproduction is constructed on the infinite set of equally spaced data.A new basis function is constructed by making convolution integral with a constructed spline and a given radial basis function.In particular,for twicely differ- entiable function the proposed method provides better approximation and also takes care of derivatives approximation.

Consolidated cluster systems for data centers in the cloud age： a survey and analysis

In the cloud age, heterogeneous application modes on large-scale infrastructures bring about the chal- lenges on resource utilization and manageability to data cen- ters. Many resource and runtime management systems are developed or evolved to address these challenges and rele- vant problems from different perspectives. This paper tries to identify the main motivations, key concerns, common fea- tures, and representative solutions of such systems through a survey and analysis. A typical kind of these systems is gener- alized as the consolidated cluster system, whose design goal is identified as reducing the overall costs under the quality of service premise. A survey on this kind of systems is given, and the critical issues concerned by such systems are sum- marized as resource consolidation and runtime coordination. These two issues are analyzed and classified according to the design styles and external characteristics abstracted from the surveyed work. Five representative consolidated cluster systems from both academia and industry are illustrated and compared in detail based on the analysis and classifications. We hope this survey and analysis to be conducive to both de- sign implementation and technology selection of this kind of systems, in response to the constantly emerging challenges on infrastructure and application management in data centers.

Nested-PCR assay for detection of Schistosoma japonicum infection in domestic animals

Background:Schistosomiasis japonica is a common zoonosis.Domestic animals are the primary source of infection and play an important role in disease transmission.The prevalence and infectivity of this disease in domestic animals in China have significantly decreased and,for this reason,diagnostics with a higher sensitivity have become increasingly necessary.It was reported that polymerase chain reaction(PCR)-based methods could be used to detect schistosome infection in humans and animals and presented a high sensitivity and specificity.The present study aimed to develop a PCR-based method for detection of Schistosoma japonicum infection in domestic animals.Methods:A specific nested-PCR assay was developed to detect S.japonicum infection in domestic animals via amplification of a 231-bp DNA fragment of retrotransposon SjR2.The developed assay was first used in sera and dry blood filter paper(DBFP)from goats and buffaloes at different time points of infection.Then,78 DBFPs from 39 artificially-infected bovines at 14 and 28 days post-infection and 42 DBFPs from schistosome-negative bovines from the city of Huangshan in the Anhui province were used to evaluate the diagnostic validity.Furthermore,this assay was used to detect S.japonicum infection in domestic animals in Dongzhi and Wangjiang counties.Results:The expected PCR product was detected in eggs and adult worms of S.japonicum and blood samples from S.japonicum-infected goats and water buffaloes,but not from Fasciola and Haemonchus contortus worms.The nested-PCR assay could detect the target S.japonicum DNA in DBFPs from goats and buffaloes after day 3 post-infection.The sensitivity in buffaloes at 14 and 28 days post-infection was 92.30%(36/39)and 100%(39/39),respectively.The specificity was 97.60%(41/42).The positivity rates in Dongzhi and Wangjiang counties were 6.00%and 8.00%in bovines and 22.00%and 16.67%in goats,respectively.The positivity rates in goats in both counties were higher than those in bovines with a significant difference in Dongzhi County but not in Wangjiang County(P<0.05 and P=0.23,respectively).Conclusions:Our results suggest that the developed nested-PCR assay may be used for the diagnosis of S.japonicum infection in domestic animals,and the control of S.japonicum infection in goats should be paid more attention.

CirroData: Yet Another SQL-on-Hadoop Data Analytics Engine with High Performance

This paper presents CirroData,a high-performance SQL-on-Hadoop system designed for Big Data analytics workloads.As a home-grown enterprise-level online analytical processing(OLAP)system with more than seven-year research and development(R&D)experiences,we share our design details to the community about how to achieve high performance in CirroData.Multiple optimization techniques have been discussed in the paper.The effectiveness and the efficiency of all these techniques have been proved by our customers'daily usage.Benchmark-level studies,as well as several real application case studies of CirroData,have been presented in this paper.Our evaluations show that CirroData can outperform various types of counterpart database systems in the community,such as"Spark+Hive","Spark+HBase",Impala,DB-X/Y,Greenplum,HAWQ,and others.CirroData can achieve up to 4.99x speedup compared with Greenplum,HAWQ,and Spark in the standard TPC-H queries.Application-level evaluations demonstrate that CirroData outperforms"Spark+Hive"and"Spark+HBase"by up to 8.4x and 38.8x,respectively.In the meantime,CirroData achieves the performance speedups for some application workloads by up to 20x,100x,182.5x,92.6x,and 55.5x as compared with Greenplum,DB-X,Impala,DB-Y,and HAWQ,respectively.