Engineering the coordination structure of Cu for enhanced photocatalytic production of C_(1)chemicals from glucose

Photocatalytic decomposition of sugars is a promising way of providing H_(2),CO,and HCOOH as sus-tainable energy vectors.However,the production of C_(1)chemicals requires the cleavage of robust C−C bonds in sugars with concurrent production of H_(2),which remains challenging.Here,the photo-catalytic activity for glucose decomposition to HCOOH,CO(C_(1)chemicals),and H_(2)on Cu/TiO_(2)was enhanced by nitrogen doping.Owing to nitrogen doping,atomically dispersed and stable Cu sites resistant to light irradiation are formed on Cu/TiO_(2).The electronic interaction between Cu and nitrogen ions originates valence band structure and defect levels composed of N 2p orbit,distinct from undoped Cu/TiO_(2).Therefore,the lifetime of charge carriers is prolonged,resulting in the pro-duction of C_(1)chemicals and H_(2)with productivities 1.7 and 2.1 folds that of Cu/TiO_(2).This work pro-vides a strategy to design coordinatively stable Cu ions for photocatalytic biomass conversion.

Dietary polyphenols reduced the allergenicity ofβ-lactoglobulin via non-covalent interactions:a study on the structure-allergenicity relationship

Studies showed that complexation of polyphenols with milk allergens reduced their immunogenic potential.However,the relationship between structures of polyphenols and their hypoallergenic effects on milk allergens in association with physiological and conformational changes of the complexes remain unclear.In this study,polyphenols from eight botanical sources were extracted to prepare non-covalent complexes withβ-lactoglobulin(β-LG),a major allergen in milk.The dominant phenolic compounds bound toβ-LG with a diminished allergenicity were identified to investigate their respective role on the structural and allergenic properties ofβ-LG.Extracts from Vaccinium fruits and black soybeans were found to have great inhibitory effects on the IgE-and IgG-binding abilities ofβ-LG.Among the fourteen structure-related phenolic compounds,flavonoids and tannins with larger MWs and multi-hydroxyl substituents,notably rutin,EGCG,and ellagitannins were more potent to elicit changes on the conformational structures ofβ-LG to decrease the allergenicity of complexedβ-LG.Correlation analysis further demonstrated that a destabilized secondary structure and protein depolymerization caused by polyphenol-binding were closely related to the allergenicity property of formed complexes.This study provides insights into the understanding of structure-allergenicity relationship ofβ-LG-polyphenol interactions and would benefit the development of polyphenol-fortified matrices with hypoallergenic potential.

Emerging structures and dynamic mechanisms ofγ-secretase for Alzheimer’s disease

γ-Secretase,called“the proteasome of the membrane,”is a membrane-embedded protease complex that cleaves 150+peptide substrates with central roles in biology and medicine,including amyloid precursor protein and the Notch family of cell-surface receptors.Mutations inγ-secretase and amyloid precursor protein lead to early-onset familial Alzheimer’s disease.γ-Secretase has thus served as a critical drug target for treating familial Alzheimer’s disease and the more common late-onset Alzheimer’s disease as well.However,critical gaps remain in understanding the mechanisms of processive proteolysis of substrates,the effects of familial Alzheimer’s disease mutations,and allosteric modulation of substrate cleavage byγ-secretase.In this review,we focus on recent studies of structural dynamic mechanisms ofγ-secretase.Different mechanisms,including the“Fit-Stay-Trim,”“Sliding-Unwinding,”and“Tilting-Unwinding,”have been proposed for substrate proteolysis of amyloid precursor protein byγ-secretase based on all-atom molecular dynamics simulations.While an incorrect registry of the Notch1 substrate was identified in the cryo-electron microscopy structure of Notch1-boundγ-secretase,molecular dynamics simulations on a resolved model of Notch1-boundγ-secretase that was reconstructed using the amyloid precursor protein-boundγ-secretase as a template successfully capturedγ-secretase activation for proper cleavages of both wildtype and mutant Notch,being consistent with biochemical experimental findings.The approach could be potentially applied to decipher the processing mechanisms of various substrates byγ-secretase.In addition,controversy over the effects of familial Alzheimer’s disease mutations,particularly the issue of whether they stabilize or destabilizeγ-secretase-substrate complexes,is discussed.Finally,an outlook is provided for future studies ofγ-secretase,including pathways of substrate binding and product release,effects of modulators on familial Alzheimer’s disease mutations of theγ-secretase-substrate complexes.Comprehensive understanding of the functional mechanisms ofγ-secretase will greatly facilitate the rational design of effective drug molecules for treating familial Alzheimer’s disease and perhaps Alzheimer’s disease in general.

Fine-tuning electronic structure of N-doped graphitic carbon-supported Co-and Fe-incorporated Mo_(2)C to achieve ultrahigh electrochemical water oxidation activity

Mo_(2)C is an excellent electrocatalyst for hydrogen evolution reaction(HER).However,Mo_(2)C is a poor electrocatalyst for oxygen evolution reaction(OER).Herein,two different elements,namely Co and Fe,are incorporated in Mo_(2)C that,therefore,has a finely tuned electronic structure,which is not achievable by incorporation of any one of the metals.Consequently,the resulting electrocatalyst Co_(0.8)Fe_(0.2)-Mo_(2)C-80 displayed excellent OER catalytic performance,which is evidenced by a low overpotential of 214.0(and 246.5)mV to attain a current density of 10(and 50)mA cm^(-2),an ultralow Tafel slope of 38.4 mV dec^(-1),and longterm stability in alkaline medium.Theoretical data demonstrates that Co_(0.8)Fe_(0.2)-Mo_(2)C-80 requires the lowest overpotential(1.00 V)for OER and Co centers to be the active sites.The ultrahigh catalytic performance of the electrocatalyst is attributed to the excellent intrinsic catalytic activity due to high Brunauer-Emmett-Teller specific surface area,large electrochemically active surface area,small Tafel slope,and low chargetransfer resistance.

Designing Symmetric Gradient Honeycomb Structures with Carbon‑Coated Iron‑Based Composites for High‑Efficiency Microwave Absorption

The impedance matching of absorbers is a vital factor affecting their microwave absorption(MA)properties.In this work,we controllably synthesized Material of Institute Lavoisier 88C(MIL-88C)with varying aspect ratios(AR)as a precursor by regulating oil bath conditions,followed by one-step thermal decomposition to obtain carbon-coated iron-based composites.Modifying the precursor MIL-88C(Fe)preparation conditions,such as the molar ratio between metal ions and organic ligands(M/O),oil bath temperature,and oil bath time,influenced the phases,graphitization degree,and AR of the derivatives,enabling low filler loading,achieving well-matched impedance,and ensuring outstanding MA properties.The MOF-derivatives 2(MD_(2))/polyvinylidene Difluoride(PVDF),MD_(3)/PVDF,and MD4/PVDF absorbers all exhibited excellent MA properties with optimal filler loadings below 20 wt%and as low as 5 wt%.The MD_(2)/PVDF(5 wt%)achieved a maximum effective absorption bandwidth(EAB)of 5.52 GHz(1.90 mm).The MD_(3)/PVDF(10 wt%)possessed a minimum reflection loss(RL_(min))value of−67.4 at 12.56 GHz(2.13 mm).A symmetric gradient honeycomb structure(SGHS)was constructed utilizing the high-frequency structure simulator(HFSS)to further extend the EAB,achieving an EAB of 14.6 GHz and a RL_(min) of−59.0 dB.This research offers a viable inspiration to creating structures or materials with high-efficiency MA properties.

The Tension Cosmology, Largest Cosmic Structures and Explosions of Supernovae from SST

Here, using the Scale-Symmetric Theory (SST) we explain the cosmological tension and the origin of the largest cosmic structures. We show that a change in value of strong coupling constant for cold baryonic matter leads to the disagreement in the galaxy clustering amplitude, quantified by the parameter S8. Within the same model we described the Hubble tension. We described also the mechanism that transforms the gravitational collapse into an explosion—it concerns the dynamics of virtual fields that lead to dark energy. Our calculations concern the Type Ia supernovae and the core-collapse supernovae. We calculated the quantized masses of the progenitors of supernovae, emitted total energy during explosion, and we calculated how much of the released energy was transferred to neutrinos. Value of the speed of sound in the strongly interacting matter measured at the LHC confirms that presented here model is correct. Our calculations show that the Universe is cyclic.

Evaluation of Technical Education by Using a Modern Structured MOODLE Laboratory Course, in Relation to Recent Data

E-learning platforms support education systems worldwide, transferring theoretical knowledge as well as soft skills. In the present study high-school pupils’, and adult students’ opinions were evaluated through a modern structured MOODLE interactive course, designed for the needs of the laboratory course “Automotive Systems”. The study concerns Greek secondary vocational education pupils aged 18 and vocational training adult students aged 20 to 50 years. The multistage, equal size simple random cluster sample was used as a sampling method. Pupils and adult students of each cluster completed structured 10-question questionnaires both before and after attending the course. A total of 120 questionnaires were collected. In general, our findings disclosed that the majority of pupils and adult students had significantly improved their knowledge and skills from using MOODLE. They reported strengthening conventional teaching, using the new MOODLE technology. The satisfaction indices improved quite, with the differences in their mean values being statistically significant.

Temporal change of plankton size structure preserved by Lugol's solution:a FlowCAM study

Plankton size structure is crucial for understanding marine ecosystem dynamics and the associated biogeochemical processes.A fixation step by acid Lugol’s solution has been commonly employed to preserve plankton samples in the field.However,the acid Lugol’s solution can bias the estimation of size structure and the preserved plankton size structure can vary with time.Here,we explore the impact of sample storage time on the size-structure of the plankton community preserved by Lugol’s solution.Two short-term experiments and one long-term experiment were conducted to explore the change of plankton community size structure with the storage time:covering from a week to a month,and to nearly seven months based on particle-size data obtained by continuous Flow Cytometer and Microscope(FlowCAM)measurements.We found a linear change of plankton size with the storage time in short-term periods(less than 3 months)with a decrease of the slope but an increase of the intercept for the normalized biomass size spectrum(NBS S).However,there were opposite trends for NBSS with increasing slope but decreasing intercept after3 months.The potential causes of the distinct patterns of the NBSS parameters are addressed in terms of the interplay between particle aggregation and fragmentation.We found large changes in plankton biovolume and abundance among different size classes,which may indicate a distinct effect of acid Lugol’s solution on various plankton size classes.The mechanism driving temporal change in the size-structure of the Lugolfixed plankton community was further discussed in terms of particle aggregation and fragmentation.Finally,we emphasize that the effect of storage time should be taken into account when interpreting or comparing data of plankton community acquired from samples with various storage durations.

Binary molten salt in situ synthesis of sandwich-structure hybrids of hollowβ-Mo2C nanotubes and N-doped carbon nanosheets for hydrogen evolution reaction

Focused exploration of earth-abundant and cost-efficient non-noble metal electrocatalysts with superior hydrogen evolution reaction(HER)performance is very important for large-scale and efficient electrolysis of water.Herein,a sandwich composite structure(designed as MS-Mo2C@NCNS)ofβ-Mo2C hollow nanotubes(HNT)and N-doped carbon nanosheets(NCNS)is designed and prepared using a binary NaCl–KCl molten salt(MS)strategy for HER.The temperature-dominant Kirkendall formation mechanism is tentatively proposed for such a three-dimensional hierarchical framework.Due to its attractive structure and componential synergism,MS-Mo2C@NCNS exposes more effective active sites,confers robust structural stability,and shows significant electrocatalytic activity/stability in HER,with a current density of 10 mA cm-2 and an overpotential of only 98 mV in 1 M KOH.Density functional theory calculations point to the synergistic effect of Mo2C HNT and NCNS,leading to enhanced electronic transport and suitable adsorption free energies of H*(ΔGH*)on the surface of electroactive Mo2C.More significantly,the MS-assisted synthetic methodology here provides an enormous perspective for the commercial development of highly active non-noble metal electrocatalysts toward efficient hydrogen evolution.

Genetic diversity and population structure of the sea star Asterias amurensis in the northern coast of China

The sea star Asterias amurensis is widely viewed as a severe“marine pest”because of its broad feeding habits.Over the past few decades,A.amurensis undergoes massive and sporadic population outbreaks worldwide,causing extensive economic and ecological losses to the local aquaculture industry and marine ecosystem.Understanding the genetic diversity and population structure of A.amurensis can provide vital information for resource management.By analyzing the polymorphism of the mitochondrial cytochrome C oxidase subunit I(COI)gene and ten simple sequence repeat(SSR)microsatellites markers,the genetic diversity and population structure of A.amurensis of four populations along the northern coast of China was uncovered.A total of 36 haplotypes were identified,and a main haplotype was found in four populations.The Qingdao(QD)population displayed the highest genetic diversity among all the populations.The AMOVA and pairwise F_(st)showed that there was small but statistically significant population differentiation among the four populations,especially between QD and Weihai(WH).Moreover,the principal component analysis(PCA)and admixture analysis showed that several individuals in Yantai(YT)and Dalian(DL)had little genetic association with other individuals.Overall,this study provided useful information of the genetic diversity and population structure of A.amurensis and will contribute to the resource management of A.amurensis in China.

妊娠糖尿病患者蛋白C、蛋白S和抗凝血酶Ⅲ水平及其与孕周的关系

目的探讨妊娠糖尿病(GDM)患者蛋白C(PC)、蛋白S(PS)和抗凝血酶Ⅲ(ATⅢ)水平及其与孕周的关系。方法选择2019年1月至2023年3月在医院就诊的232例GDM孕妇作为观察组,同时随机选取同期在医院进行孕检的268例正常孕妇作为对照组,比较两组一般资料和PC、PS和ATⅢ水平;按孕周将观察组和对照组分为孕中期和孕晚期,分别比较孕中期和孕晚期观察组和对照组PC、PS和ATⅢ水平。通过相关性分析,分析PC、PS和ATⅢ水平与孕周的相关性。结果与对照组相比,观察组PS和PC水平降低(P<0.05),但ATⅢ水平差异无统计学意义(P>0.05)。GDM患者PC和ATⅢ水平与孕周呈负相关(r=-0.156、-0.134,P<0.05)。结论GDM患者PS和PC水平降低,且随孕周增大,PC、PS和ATⅢ水平降低,应尽早进行干预,以减少血栓形成的风险。

The Inner Structure of the Intrinsic Electron and the Origin of Self-Mass

A brief review and analysis of two historical models of the electron, the charged spinning sphere and Goudsmit and Uhlenbeck’s concept, is presented. It is shown that the enormous potential of classical electrodynamics has been underutilized in particle physics. Such observation leads to discovery of a principal component in the electron inner structure—the charged c-ring. The intrinsic (fundamental) electron model based on the charged c-ring successfully explains the ontology of the charge fractionation in quantum chromodynamics and the formation of Cooper pairs in superconductivity. The c-ring properties are explained on the basis of the General Compton Conditions as defined. Properties of the charged c-ring include the explanation of the boundary conditions, electro-magnetostatic field configuration, self-mass, spin, magnetic moment, and the gyromagnetic ratio. The self-mass of the intrinsic electron is 100% electro-magnetostatic and it is shown how to compute its value. The classical-quantum divide no longer exists. Relation between the intrinsic electron and the electron is fundamentally defined. The electron is the composite fermion consisting of the intrinsic electron and the neutrino. The ontology of the anomaly in the electron magnetic moment is demonstrated—it is due to the addition of the neutrino magnetic moment to the overall electron magnetic moment. The intrinsic electron replaces the W? boson in particle physics, resulting in a fundamental implication for the Standard Model.

基于C/S架构和物联网技术的可移动医疗设备共享调配系统的设计与应用

目的 设计一个可移动医疗设备高效管理与临床科室共享调配相结合的医疗设备共享管理平台,实现可移动医疗设备使用的全过程管理。方法 基于C/S架构,利用物联网技术优化整合现有医疗设备大数据资源,结合医院需求,构建可移动医疗设备共享调配系统,实现医疗设备共享管理、预约借用、统计分析等核心功能。通过比较系统上线前后呼吸机调配次数、平均调配时间、呼吸机使用率、单台呼吸机日均收入4个指标,分析系统应用效果。结果 系统上线后,呼吸机调配次数明显增加、平均调配时间明显降低,呼吸机使用率、单台呼吸机日均收入明显升高,且差异均有统计学意义(P﹤0.05),表明系统对提高呼吸机调配效率与使用效率有促进作用。结论 可移动医疗设备共享调配系统优化了医院设备管理流程,实现了医疗资源的统一调配,有效满足临床紧急抢救时医疗设备调配使用的相关需求,提高了医疗设备周转率以及设备管理人员的工作效率,有助于医院节约人员成本、降低采购费用,为医院管理者制定相关决策提供数据支撑。

纳米C-S-H/PCE对蒸养UHPC力学性能增强机理研究

目前超高性能混凝土(UHPC)制品的力学性能有待进一步提升,采用纳米C-S-H/PCE对UHPC进行增强在理论上是一种可行的技术途径。本文研究了蒸养条件下掺入以聚羧酸(PCE)为分散剂的纳米水化硅酸钙(C-S-H/PCE)对UHPC力学性能的影响,通过测试水化热、水化产物、微观形貌和孔结构等对其机理进行了分析。结果表明,掺入3.0%(质量分数)纳米C-S-H/PCE可以显著提高蒸养UHPC的抗压强度和抗折强度。掺入纳米C-S-H/PCE可以促进UHPC的早期水化,生成更多的水化硅酸钙(C-S-H)凝胶,使水化放热温峰增高,并缩短达到水化温峰的时间。掺入纳米C-S-H/PCE可有效改善蒸养UHPC的孔结构,在掺量为3.0%(质量分数)时总孔隙率最小,有害孔比例最低。该研究可为纳米C-S-H/PCE在蒸养UHPC中的应用提供参考。

NOTCH3基因C260S位点突变导致CADASIL的临床和影像学特征分析

目的探讨NOTCH3基因第5外显子C260S位点突变导致的伴有皮层下梗死和白质脑病的常染色体显性遗传性脑动脉病(cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy,CADASIL)家系的临床和影像学特征。方法选取2021年12月首都医科大学附属北京同仁医院来自同一家庭的CADASIL患者,对所有患者进行NOTCH3基因测序,回顾性分析患者的临床表现和头颅影像学特征。复习既往文献报道的导致同一位置氨基酸改变的其他突变类型的临床及影像学特征。结果4名家庭成员中,包括先证者(46岁,女)及其两个姐姐(分别为48岁和50岁)和女儿(18岁)。先证者及其父亲、两个姐姐都有偏头痛病史,其中大姐有记忆力减退;先证者患有脑梗死及伴有视觉先兆的偏头痛;先证者女儿体健;先证者父亲因脑梗死去世。4名家庭成员均存在C260S位点的NOTCH3基因突变。既往文献无此位点突变的报道,先证者头颅MRI示右侧脑桥亚急性梗死,颞叶、脑室周围及脑干异常高信号改变,其大姐脑桥可见腔隙性梗死灶。结论NOTCH3基因第5外显子c.778T>A(p.C260S)的罕见突变导致的CADASIL发病时间早,早期会出现认知障碍。合并偏头痛的脑干梗死患者,需警惕CADASIL的可能。

不同溶剂预处理煤在ScCO_(2)作用下的谱学差异及其机制

为了探究溶剂预处理后超临界二氧化碳(ScCO_(2))对煤化学结构的影响,以长治霍尔辛赫贫煤为研究对象,分别用四氢呋喃(THF)、盐酸(HCI)和氢氟酸(HF)对煤样进行预处理,采用傅里叶红外光谱(FTIR)、固体核磁共振(^(13)C-NMR)和X射线衍射(XRD)测试,探讨了ScCO_(2)对预处理煤的化学组成和结构的影响机理。研究表明:①FITR分峰拟合谱图实验曲线基本一致,而各官能团吸收峰位置及峰强度仍出现一定的偏差,酸(HCI、HF)预处理后部分波段脂肪族峰位消失。两类酸预处理顺序不同,对煤中含氧官能团、脂肪结构及芳烃结构作用效果也不相同。HF-HCI处理后芳烃C=C结构和含氧官能团峰强度均增强,而HCI-HF处理后芳烃C=C结构强度减弱,含氧官能团结构峰强度变化不明显。THF预处理后煤样芳烃C=C结构峰强度增强,含氧官能团结构峰强度降低。总体芳烃C=C结构峰强度远大于脂肪族结构和含氧官能团结构的峰强度。②^(13)C-NMR谱中主要官能团谱峰的化学位移出现了一定程度的偏移,芳香碳f_(a)^(B)化学位移向增大的方向偏移。大分子结构参数中,芳香碳含量远大于脂肪碳含量,说明煤大分子结构中芳香碳占主要组成部分。③XRD谱中002峰与101峰衍射强度明显增大,芳香微晶层网面间距d_(002)呈现升高趋势,说明THF、酸(HF、HCI)处理和ScCO_(2)对煤大分子结构产生了一定程度的改造作用,使煤的大分子网络结构变得疏松,进而使微晶结构参数d_(002)整体增大。研究认为,溶剂作用后煤的谱学特征变化不仅与溶剂性质有关,还与无机酸处理顺序有关,由此使得官能团组成和大分子结构不同程度改变,进而影响ScCO_(2)对预处理煤的萃取效果。

基于STC12C5A60S2的温湿度控制系统设计

文章针对环境温湿度对纺织生产影响很大的情况,设计温湿度控制系统。系统采用STC12C5A60S2为控制核心,由DHT11进行数据采集,并且采用直观的1602LCD数字显示模块,以实现温度和湿度实时显示,高温时启动外部负载降温,低温时外部负载停止工作的控制,以将温湿度控制在一定的范围内,可以帮助纺织厂生产区域控制环境温湿度,确保纺织厂的温湿度符合要求。

基于剩余电流和不平衡电流突变向量比的TN-C-S系统漏电故障检测方法

TN-C-S系统在我国应用广泛,但由于固有剩余电流大,无法区分负荷投切和故障引起的剩余电流变化,漏电总保和中保无法投运,存在安全隐患。针对该问题,提出一种基于剩余电流和不平衡电流突变量之比的漏电故障保护方法。首先,分析剩余电流回路,剩余电流和不平衡电流突变量之比在单相接地故障发生时刻突变,在负荷投切时不变。其次,基于中性线阻抗和接地阻抗不会发生突变的特征,计算故障电流突变量幅值,以故障电流突变量幅值越限作为故障判别依据,实现漏电故障检测。仿真及试验证明,所提方法可有效区分负荷投切和漏电故障,实现大幅值固有剩余电流下的漏电故障检测,在单支路和多支路系统中的检测灵敏度分别为70、150 mA,满足TN-C-S系统多级漏电保护的灵敏度要求。

The Intrinsic Electron with Its Properties Such as Inner Structure and Self-Mass Is in Conflict with Quantum Field Theory

The quantum field theory (QFT) is one of branches of the Standard Model. According to QFT, quantum fields are the primary entities and particles are the excitations of these fields, coming in discrete lumps with no inner structures and with properties assigned by declaration. Such view is in conflict with the observed vacuum energy density, 140 orders of magnitudes less than required by the QFT. In addition, such view is challenged by Aphysical Quantum Mechanics (AQM), a deeper quantum theory. According to AQM, the fundamental understanding of quantum reality is expanded by the addition of two fundamental categories, aphysical and elementary consciousness of elementary particles. Based on AQM and as an example, the total ontology of the intrinsic (fundamental) electron is presented with its inner structure of perfect geometry consisting of the physical charged c-ring and aphysical cylinder, and with its properties such as self-mass, spin, magneto-electrostatic field configuration and magnetic moment. The position parameter in the inner structure demonstrates that there are no two identical intrinsic electrons in the Universe thus placing a question mark over the QFT principle of indistinguishability.

10℃条件下纳米C-S-H掺量对水泥早期水化的影响

目的探究10℃条件下不同掺量纳米C-S-H对水泥早期水化进程及强度发展的影响,并分析其早强剂作用机理。方法通过溶液共沉淀法制备纳米C-S-H悬浮液,将其掺入到普通硅酸盐水泥中,在10℃条件下进行养护,分析其对水泥凝结时间、抗折强度、抗压强度的影响;通过XRD、TG等检测手段分析水泥的水化进程及对水化产物的影响。结果掺入0.05%纳米C-S-H,可使水泥初凝时间缩短9.9%,终凝时间缩短10.4%;24 h时抗折强度和抗压强度分别提高了34%和33.5%。纳米C-S-H的掺入造成水泥3 d抗折强度略有降低。水化产物中Ca(OH)2质量分数在12 h、16 h和24 h时较参比样分别提高了17.6%、21.3%和29.6%。结论在10℃条件下,纳米C-S-H的加入能够有效促进C 3S和C 2S的水化过程,形成更多的水化产物,从而缩短水泥凝结时间,提高24 h内水泥砂浆强度,28 d强度没有显著降低。