Study on Acoustic Emission Characteristics of Self-Compacting Concrete under Uniaxial Compression Test

To study the relationship between acoustic emission characteristic parameters of self-compacting concrete(SCC)and its destruction evolution,under uniaxial compression,acoustic emission(AE)tests are performed on C30 selfcompacting concrete test blocks that are preserved for 7 days and 28 days,the corresponding relationship among energy,amplitude,ring count and different failure stages of the specimens are analyzed by AE experiment,and the spatial distribution of AE in each stage is described by introducing location map.The test shows that there are two rules for the failure of SCC specimens cured for 7 days and 28 days:(1)The first failure law is divided into four stages according to the percentage of the stress value reaching the limit stress:Initial stage:above 10%,the compaction time of test block cured for 28 days is relatively low;Elastic failure stage:30%–35%,the cumulative value of each parameter increases linearly,and the cumulative value of the amplitude is the largest;Crack stable propagation stage:35%–90%,there is a moment that causes local stress concentration in both test blocks;Active stage:above 90%,the cumulative value of the parameter rises sharply,then continues to load the test block instability and damage.(2)The second failure law is divided into five stages according to the percentage of the stress value reaching the limit stress:Initial stage:15%–20%,the cumulative value of each parameter increases with time;Elastic failure stage:20%–40%,the cumulative value of the parameter continues to grow,but the growth curve is approximately parallel;Crack stable propagation stage:40%–60%,all parameters increased sharply and the increase reached the peak of the whole process;A stable state:60–80%,the emission characteristic parameter will become zero,and the stable state of the 28 days curing test block is lagging;Active stage:above 90%,the number of signals increased sharply,but the energy and amplitude are low,and the later test block is completely fractured.(3)In the process of failure,the test block of SCC will form an inverted triangle or landslide failure surface,and the part above the failure surface is prone to failure,and there is a tendency to leave the test block.(4)Under uniaxial compression,the penetration of SCC cracks is mostly shear penetration.

Concrete Physics Method for Solving NP hard Problem

With a NP hard problem given, we may find a equivalent physical world. The rule of the changing of the physical states is simply the algorithm for solving the original NP hard problem .It is the most natural algorithm for solving NP hard problems. In this paper we deal with a famous example , the well known NP hard problem——Circles Packing. It shows that our algorithm is dramatically very efficient. We are inspired that, the concrete physics algorithm will always be very efficient for NP hard problem.

The dynamic changes of genes revealed that persistently overexpressed genes drive the evolution of cyflumetofen resistance in Tetranychus cinnabarinus

Changes in gene expression are associated with the evolution of pesticide resis-tance in arthropods.In this study,transcriptome sequencing was performed in 3 different resistance levels(low,L;medium,M;and high,H)of cyflumetofen-resistant strain(YN-CyR).A total of 1685 genes,including 97 detoxification enzyme genes,were upregulated in all 3 stages,of which 192 genes,including 11 detoxification enzyme genes,showed a continuous increase in expression level with resistance development(L to H).RNA in-terference experiments showed that overexpression of 7 genes(CYP392A1,TcGSTd05,CCE06,CYP389A1,TcGSTz01,CCE59,and CYP389C2)is involved in the development of cyflumetofen resistance in Tetranychus cinnabarinus.The recombinant CYP392A1 can effectively metabolize cyflumetofen,while CCE06 can bind and sequester cyflumetofen in vitro.We compared 2 methods for rapid screening of resistance molecular markers,in-cluding short-term induction and 1-time high-dose selection.Two detoxification enzyme genes were upregulated in the field susceptible strain(YN-S)by induction with 20%lethal concentration(LC2o)of cyflumetofen.However,16 detoxification enzyme genes were up-regulated by 1-time selection with LCso of cyflumetofen.Interestingly,the 16 genes were overexpressed in all 3 resistance stages.These results indicated that 1685 genes that were upregulated at the L stage constituted the basis of cyflumetofen resistance,of which 192 genes in which upregulation continued to increase were the main driving force for the de-velopment of resistance.Moreover,the 1-time high-dose selection is an efficient way to rapidly obtain the resistance-related genes that can aid in the development of resistance markers and resistance management in mites.