多维地震下钢管混凝土柱-组合梁框架结构体系抗震性能分析

基于柱端拉筋对钢管混凝土柱、钢管混凝土柱-组合梁节点和钢管混凝土柱-组合梁平面框架结构抗震性能影响的试验研究成果,建立了钢管混凝土柱-组合梁空间框架结构动力时程分析的三维实体-壳单元模型,探讨了柱端拉筋和主梁加高等增强约束措施、削减钢梁跨中腹板高度的变截面组合梁以及多维地震波对结构抗震性能的影响规律,分析了不同地震波强度作用下该类组合框架结构的位移响应、轴压比时程曲线、应力-应变等曲线,以及结构塑性耗能分配机制、塑性铰形成与发展规律和结构刚度损伤演化规律等抗震性能指标。有限元计算结果表明:1)柱端拉筋和主梁加高等增强约束措施均能有效提升组合框架结构抗震性能而减小结构刚度损伤,且地震波强度越大作用效果越明显;相同地震波作用时,柱端拉筋增强约束措施比主梁加高增强约束措施更有效,而两种增强约束措施共同作用则能进一步提升组合结构的极限抗震能力。2)柱端拉筋增强约束措施能够降低钢管壁与混凝土间界面滑移,增强混凝土的耗能能力,降低钢管混凝土柱塑性耗能占比,提升钢梁塑性耗能占比,提升结构总塑性耗能;此外,柱端拉筋增强约束措施还可减少组合框架柱端塑性铰并增加梁端塑性铰的数量,延缓柱端“压铰”的出现,延长“压铰”向“拉铰”转变的过程。3)降低钢梁跨中腹板高度的变截面组合梁对框架结构抗震性能没有影响,采用该变截面组合梁的框架模型不仅能够满足结构基本功能要求,还可节省结构耗材、降低造价,进一步扩大建筑实用空间。4)与单向地震波作用相比,多维地震波作用下组合框架结构的极限抗震能力大幅下降,结构失效模式由剪切破坏转变为剪扭破坏。另外,三维地震波中竖向加速度对框架结构柱端轴压比有放大作用,而对楼层最大位移、层间位移角、塑性耗能和刚度损伤等方面则无明显影响。柱端拉筋增强约束措施对组合框架结构抗震性能仍有提升作用。

Axial and radial electromagnetic-vibration characteristics of converter transformer windings under current harmonics

The winding current harmonic content of converter transformer in operation is rich.However,affected by harmonics,the radial vibration characteristics are quite different from the power transformer,structural loosening and deformation caused by winding vibration are more prominent.Therefore,in view of the influence of current harmonics on axial and radial vibrations,this study builds a 3D winding electromagnetic vibration finite element simulation model,analyses the components and contents of current harmonics,compares the leakage flux and vibration distribution under the fundamental,harmonic and superimposed currents.The correlation relationship between the harmonic components and axial and radial vibration characteristics is obtained,and the vibration measurement test of±800 kV converter transformer in operation is carried out to verify the correctness of the analysis method.The results show that the winding radial vibration amplitude will exceed the axial vibration affected by harmonics.More importantly,under the superposition of the fundamental,5th and 7th harmonic current,the vibration contribution of the converter transformer tank is mainly radial vibration,and the vibration dominant frequency is shifted from 100 Hz under the fundamental current to 400 Hz.

In-situ construction of Co(OH)_(2) nanoparticles decorated biochar for highly efficient degradation of tetracycline hydrochloride via peracetic acid activation

Peracetic acid(CH_(3)C(O)OOH,PAA)-based heterogeneous advanced oxidation process(AOP)has attacked intensive interests due to production of various reactive species.Herein,Co(OH)_(2)nanoparticles decorated biochar(Co(OH)_(2)/BC)was fabricated by a simple and controllable method,which was used to degrade tetracycline hydrochloride(TTCH)in water through PAA activation.The results indicated that 100%TTCH(C_(0)=10μmol/L)degradation efficiency was realized within 7 min at pH 7,with a high kinetic rate constant(k_(1))of 0.64 min^(-1)by the optimized Co(OH)_(2)/BC.Material characterizations suggested that Co(OH)_(2)nanoparticle was successfully decorated on biochar,leading to more active sites and electronic structure alteration of biochar,thus greatly promoting the catalytic cleavage of PAA for radicals production.Then,the reactive oxygen species(ROS)quenching experiments and electron paramagnetic resonance(EPR)analysis demonstrated the key species were alkoxyl radicals(R–O^(·),mainly CH_(3)CO_(2)^(·)and CH_(3)CO_(3)^(·)),HO^(·)and^(1)O_(2)in this system.Besides,density functional theory(DFT)calculation on Fukui index further revealed that the vulnerable sites of TTCH and three possible degradation pathways were proposed.This study can provide a new strategy for synthesis functional materials in PAA activation AOPs for removal of antibiotics in water.

Reactive species regulation by interlayered Na^(+)/H^(+)of titanate nanotubes decorated Co(OH)_(2)hollow microsphere for peroxymonosulfate activation and gatifloxacin degradation

Emerging organic pollutants(EoPs)in water are of great concern due to their high environmental risk,so urgent technologies are needed for effective removal of those pollutants.Herein,a heterogeneous advanced oxidation process(AoP)of peroxymonosulfate(PMS)activation by functional material was developed for degradation of a typical antibiotic,gatifloxacin(GAT).The reactive species including sulfate radical(SO^(4)^(·-))and singlet oxygen(^(1)O_(2))in this AOP were regulated by interlayered ions(Na^(+)/H^(+))of titanate nanotubes that supported on Co(OH)_(2)hollow microsphere.Both the Na-type(NaTi-CoHS)and H-type(HTi-CoHS)materials achieved efficient PMS activation for GAT degradation,and HTi-CoHS even exhibited a relatively high degradation efficiency of 96.6%within 5 min.Co(OH)_(2)was considered the key component for generation of SO_(4)^(·-)after PMS activation,while hydrogen titanate nanotubes(H-TNTs)promoted the transformation of peroxysulfate radical(SO_(5)^(·-))to ^(1)O_(2) by hydrogen bond interaction.Therefore,when the interlayer ion of TNTs transformed from Na^(+) to H^(+),more ^(1)O_(2) was produced for organic pollutant degradation.H-TNTs with lower symmetry preferred to adsorb PMS molecules to achieve interlayer electron transport through hydrogen bonding,rather than electrostatic interaction of Na^(+) for Na-TNTs.In addition,the degradation pathway of GAT mainly proceeded by the cleavage of C-N bond at the 8 N site of the piperazine ring,which was confirmed by condensed Fukui index and mass spectrographic analysis.This work gives new sights into the regulation of reactive species in AoPs by the composition of material and promotes the understanding of pollutant degradation mechanisms in water treatment process.

水平地震下钢-混凝土组合框架结构极限抗震与强柱构造

“强柱弱梁”是当前国际上主流的工程结构抗震设计理念,已有地震灾害调查表明,由于地震作用机制的复杂性以及对工程结构极限抗震认识的不足,强震作用后框架结构除出现梁铰的“强柱弱梁”破坏之外,还出现整体倒塌、柱铰以及局部楼层倒塌的“强梁弱柱”破坏。为合理认识各类破坏形式,首先对传统的塑性铰概念细分为“压铰”和“拉铰”,指出“拉铰”容易引发结构整体失稳;随后以钢-混凝土组合框架结构为对象,建立并采用实体单元与壳单元为主的组合框架结构有限元精细化抗震计算模型,开展组合结构极限抗震分析,初步探讨各水平地震波工况对组合框架结构位移、应力、轴压比等时程响应以及框架梁柱塑性耗能分配机制、塑性铰形成模式与失效机制的影响规律。分析结果显示:1)柱端拉筋减小了钢管与混凝土之间滑移,从而增大了柱和框架的刚度,降低了钢管和混凝土的应变水平,增大了钢梁的应力水平;620 cm/s^(2)及以上强度的地震波作用时,柱端拉筋构造可显著减小组合框架结构的最大层间位移角,在接近极限强度的水平地震波作用时,柱端拉筋屈服,框架梁端混凝土板纵筋一般不易屈服;2)“强梁弱柱”组合框架表现为“约束梁”与“耗能柱”,此时框架梁对框架柱约束较强,框架以框架柱耗能为主而梁端仅形成“压铰”,此时框架的耗能能力取决于框架柱;“强柱弱梁”组合框架表现为“耗能梁”与“承载柱”,此时框架梁对框架柱约束较弱,框架以框架梁耗能为主使得梁端先形成“压铰”,当梁端耗能至极限时形成“拉铰”引发框架柱长细比增大,导致框架加速失效,不利于发挥框架柱耗能潜力;3)柱端拉筋技术的“强柱”构造将提高组合结构的刚度、塑性耗能与抗倒塌能力,强柱构造对以柱耗能为主的6层框架抗震能力提升尤其显著。

The capacity and mechanisms of various oxidants on regulating the redox function of ZVI

It is well known that zero-valent iron(ZVI)could catalyze the oxidation of various oxidants to realize the rapid oxidation removal of pollutants.However,in this study,we found that the addition of different oxidants could regulate the redox function of ZVI system.In three different co-treatment systems,the effects of different oxidizers(peroxymonosulfate(PMS),persulfate(PDS),hydrogen peroxide(H_(2)O_(2)))dosages on the ratios of oxidative degradation rate and reductive degradation rate of p-nitrophenol(PNP)were studied.The effect of the H+released from oxidizers and the generated reactive oxygen species(ROS)in ZVI/PMS,ZVI/PDS,ZVI/H_(2)O_(2)systems were detailed discussed.Especially,the contribution of generated ROS for reductive degradation of PNP was quantified in the ZVI/H_(2)O_(2)system.Based on the results of TOC removal,UV-vis absorption spectra,and intermediates concentration curves,it was found that the degradation of PNP changed from reduction to oxidation with the increase of oxidant proportion.When the molar ratio of ZVI to oxidizer equal to 100,PNP was mainly degraded by reduction accompanied by slight oxidation.Combined with the results of SEM-EDS and XPS,it was confirmed that the enhanced degradation of PNP under the addition of oxidant was mainly related to the generated ROS,the additional H+,and the corrosion products of ZVI.

Reconfiguring phosphorylation signaling by genetic polymorphisms affects cancer susceptibility

Large-scale sequencing has characterized an enormous number of genetic variations(GVs),and the functional analysis of GVs is fundamental to understanding differences in disease susceptibility and therapeutic response among and within populations.Using a combination of a sequence-based predictor with known phosphorylation and protein–protein interaction information,we computationally detected 9606 potential phosSNPs(phosphorylation-related single nucleotide polymorphisms),including 720 known,disease-associated SNPs that dramatically modify the human phosSNP-associated kinase–substrate network.Further analyses demonstrated that the proteins in the network are heavily associated in various signaling and cancer pathways,while cancer genes and drug targets are significantly enriched.We re-constructed four population-specific kinase–substrate networks and found that several inherited disease or cancer genes,such as IRS1,RAF1,and EGFR,were differentially regulated by phosSNPs.Thus,phosSNPs may influence disease susceptibility and be involved in cancer development by reconfiguring phosphorylation networks in different populations.Moreover,by systematically characterizing potential phosphorylation-related cancer mutations(phosCMs)in 12 types of cancers,we observed that both types of GVs preferentially occur in the known cancer genes,while a considerable number of phosphorylated proteins,especially those over-representing cancer genes,contain both phosSNPs and phosCMs.Furthermore,it was observed that phosSNPs were significantly enriched in amplification genes identified from breast cancers and tyrosine kinase circuits of lung cancers.Taken together,these results should prove helpful for further elucidation of the functional impacts of disease-associated SNPs.

Revealing the intrinsic mechanisms for accelerating nitrogen removal efficiency in the Anammox reactor by adding Fe(Ⅱ)at low temperature

Fe(Ⅱ)is an essential trace element for anaerobic ammonium oxidation bacteria(AAOB)metabolism,and can improve the nitrogen removal efficiency of anaerobic ammonia oxidation(Anammox).Here we oper-ated two identical expanded granular sludge bed(EGSB)reactors at low temperature(15±3℃)for 154 days.Reactor 1(R_(1))received additional Fe(Ⅱ)(0.12 mmol/L)during the late startup phase,while reactor 0(R_(0))served as the control and did not receive extra Fe(Ⅱ).Nitrogen removal in R_(1)became stable at 55 d of operation,ten days earlier than R_(0).The nitrogen removal rate(NRR)of R_(1) was 1.64 kg N m^(−3)d^(−1)and its TN removal rate was as high as 89%,while R_(0)only reached 75%.The addition of Fe(Ⅱ)was fur-ther beneficial to aggregation and stability of the granular sludge,and the used sludge of both reactors showed enrichment for AAOB populations compared to the inoculum,for instance,increased abundance of Candidatus-Kuenenia and in particular of Candidatus-Brocadia(from 0.17%to 10.10%in R_(0)and 7.79%in R_(1)).Diverse microbial species and complex microbial network structure in R_(1)compared to R_(0)promoted the coupled denitrogenation by Anammox,dissimilatory nitrate reduction to ammonium(DNRA),nitrate-dependent Fe oxidation(NDFO),and ferric ammonium oxidation(Feammox).In addition,the microbial community in R_(1)was more resistant to short-term low temperature(2-7℃)starvation,illustrating a further positive effect of adding Fe(Ⅱ)during the startup phase of an Anammox reactor.