Influence of self-similar stresses on scenario earthquake construction:An example along the Tanlu Fault

As a famous deep and large fault in eastern China,the Tanlu Fault passes through Anhui,Jiangsu,and Shandong and into northeastern China.It is important to improve the understanding of seismic hazard assessments in areas near faults.We start a scenario earthquake simulation in the M7.5 earthquake potential area of the Xinyi-Sihong segment of the Tanlu Fault.The fault rupture length and width are constrained according to the scaling law of large intraplate earthquakes,the background normal stress is depth dependent,and the initial shear stresses are determined using trial and error by matching the earthquake magnitude.Considering the 120 km rupture length of the M7.5 earthquake,we compare the horizontal uniform stress model and self-similar stress perturbation model.Our findings reveal that the seismic source time function of the horizontal uniform stress model is similar to that of the Haskell model and that of the self-similar stress perturbation model is more similar to that of a real earthquake case.We compare the dynamic rupture simulation and ground motion results under four different stress conditions and find that the shorter the characteristic length of the self-similar function is,the rougher the initial stress.For the M7.5earthquake with an epicenter in the vicinity of Suqian,the Xinyi-Tancheng segment,which is located in the IX-intensity zone north of the epicenter,vibrates more strongly on the northern side than on the southern side due to the influence of the lowvelocity zone and the peak slip rate.The response spectra analysis at stations in the study area is useful for improving the earthquake resistance capability.

Spontaneous hierarchical surface engineering of minerals through coupled dissolution-precipitation chemistry

Peculiar hierarchical microstructures in creatures inspire modern material design with distinct functionalities.Creatures can effortlessly construct sophisticated yet long-range ordered microstructure across bio-membrane through ion secretion and precipitation.However,microstructure biomimicry in current technology generally requires elaborate,point-by-point fabrication.Herein,a spontaneous yet controllable strategy is developed to achieve surface microstructure engineering through a natural surface phenomenon similar to ion secretion-precipitation,that is,coupled dissolution-precipitation.A series of hierarchical microstructures on mineral surfaces in fluids with tunable morphology,orientation,dimension,and spatial distribution are achieved by simply controlling initial dissolution and fluid chemistry.In seawater,long-range ordered film of vertically aligned brucite flakes forms through interfacial dissolution,nucleation,and confinement-induced orientation of flakes with vertically grown{110}plane,on the edge of which,fusiform aragonite epitaxially precipitates.With negligible initial surface dissolution,prismatic aragonite epitaxially grows on a calcite polyhedron-packed surface.By tuning fluid chemistry,closely packed calcite polyhedron and loosely packed calcite micro-pillars are engineered through rapid and retarded precipitation,respectively.Surprisingly,the spontaneously grown microstructures resemble those deliberately created by human or found in nature,and tremendously modulate surface functionality.These findings open new possibilities for facile and customizable engineering of microstructural surfaces,hierarchical heterostructures,and biomimetic materials.

The Use of Floss in Medical Faculties of Inner Mongolia Medical University in 2017

Purpose: The aim of the present study was to determine the degree of using floss and the demographic characteristics of medical faculties of Inner Mongolia Medical University. Materials and Methods: Participants completed the questionnaire in the classroom. These participants came from the medical faculties of Chinese Medicine and Western Medicine. These participants were interviewed to determine the demographic characteristics. Non-flossors responded according to their reasons for not flossing. Results: A total of 3481 effective data were available for analysis. The floss prevalence was 17.21%, which was lower by 5.72% for students living in rural areas, when compared to students living in urban areas. The largest proportion of non-flossing participants in rural areas answered, “I do not know what a floss is”, while participants in urban answered, “I do not want to use it”. The largest proportion of answered flossing frequency was less than once a month. Conclusion: The present study indicates that the prevalence of using floss in medical faculties in Inner Mongolia Medical University was higher, when compared to that in Sichuan province, China, but lower than that in other countries. Although the students use floss, more than one-third of students use floss less than once a month, which is close to “never”. The prevalence in rural areas is lower than those in urban areas. Male not only comprises the total number of prevalence, but also has a frequency greater than that in females. The emphasis on using floss should be improved in medical students.

基于界面改性的碳纳米管增强水泥基复合材料力学性能与机理研究

为研究界面改性的碳纳米管(CNTs)增强水泥基复合材料力学性能与机理,用酸处理CNTs的表面,并采用聚乙烯醇(PVA)作为桥联剂改善CNTs与水泥基体间的界面,首先采用XPS光谱、FTIR测试及ToF-SIMS质谱法评价CNTs的表面处理和界面结合情况,然后对比分析了水泥/PVA、水泥/a-CNTs、水泥/PVA/a-CNTs和水泥/PVA/CNTs复合材料的力学性能测试结果。结果表明:CNTs通过表面处理可以得到有效官能团,从而增强和水泥之间的连接,PVA的加入也可以有效改善CNTs与水泥的结合程度;未经处理的原始CNTs对水泥复合材料的抗折强度增强效果不明显,而含有PVA和经表面处理的CNTs的水泥复合材料,其抗折强度显著增加,可从5.52 MPa增加到12.61 MPa。研究证明,通过强化CNTs和水泥基体之间的界面,可以明显增强水泥/CNTs复合材料的力学性能。

A low-cost in-situ CO_(2) sensor based on a membrane and NDIR for long-term measurement in seawater

The multi-point simultaneous long-term measurement of CO_(2) concentration in seawater can provide more-valuable data for further understanding of the spatial and temporal distribution of CO_(2).Thus,the requirement for a low-cost sensor with high precision,low power consumption,and a small size is becoming urgent.In this work,an in-situ sensor for CO_(2) detection in seawater,based on a permeable membrane and non-dispersive infrared(NDIR)technology,is developed.The sensor has a small size(Ф66 mm×124 mm),light weight(0.7 kg in air),low power consumption(<0.9 W),low cost(<US$1000),and high-pressure tolerance(<200 m).After laboratory performance tests,the sensor was found to have a measurement range of(0–2000)×10^(-6),and the gas linear correlation R^(2) is 0.99,with a precision of about 0.98%at a sampling rate of 1 s.A comparison measurement was carried out with a commercial sensor in a pool for 7 days,and the results showed a consistent trend.Further,the newly developed sensor was deployed in Qingdao nearshore water for 35 days.The results proved that the sensor could measure the dynamic changes of CO_(2) concentration in seawater continuously,and had the potential to carry out long-term observations on an oceanic platform.It is hoped that the sensor could be applied to field ocean observations in near future.

Profiling proteomic responses to hexokinase-II depletion in terpene-producing Saccharomyces cerevisiae

Hexokinase II(Hxk2)is a master protein in glucose-mediated transcriptional repression signaling pathway.De-grading Hxk2 through an auxin-inducible protein degradation previously doubled sesquiterpene(nerolidol)pro-duction at gram-per-liter levels in Saccharomyces cerevisiae.Global transcriptomics/proteomics profiles in Hxk2-deficient background are important to understanding genetic and molecular mechanisms for improved nerolidol production and guiding further strain optimization.Here,proteomic responses to Hxk2 depletion are investi-gated in the yeast strains harboring a GAL promoters-controlled nerolidol synthetic pathway,at the exponential and ethanol growth phases and in GAL80-wildtype and gal80Δbackgrounds.Carbon metabolic pathways and amino acid metabolic pathways show diversified responses to Hxk2 depletion and growth on ethanol,including upregulation of alternative carbon catabolism and respiration as well as downregulation of amino acid synthesis.De-repression of GAL genes may contribute to improved nerolidol production in Hxk2-depleted strains.Seven-teen transcription factors associated with upregulated genes are enriched.Validating Ash1-mediated repression on the RIM4 promoter shows the variation on the regulatory effects of different Ash1-binding sites and the syner-gistic effect of Ash1 and Hxk2-mediated repression.Further validation of individual promoters shows that HXT1 promoter activities are glucose-dependent in hxk2Δbackground,but much weaker than those in HXK2-wildtype background.In summary,inactivating HXK2 may relieve glucose repression on respiration and GAL promoters for improved bioproduction under aerobic conditions in S.cerevisiae.The proteomics profiles provide a better genetics overview for a better metabolic engineering design in Hxk2-deficient backgrounds.