一种高效稳定的高熵合金电催化剂用于析氢反应

水分解是一种利用可再生能源驱动的绿色制氢方法,零碳排放特性使其成为解决氢能源生产的重要途径.在电化学水分解中,制备高活性和稳定性的催化剂至关重要.高熵合金(HEAs)由于独特的结构和性能使其成为理想的催化剂材料,其多元成分和可调组成提供了丰富的表面活性位点和灵活的催化特性,有望提高水分解的效率并降低成本.然而,简易高效地制备HEAs仍面临挑战,且目前对HEA催化剂的结构-活性关系的了解存在不足.因此,探索一种简便有效的方法用以制备高性能HEAs催化剂,并深入理解其在水分解反应中的作用机制和结构演变,能够为未来绿色制氢技术的发展提供重要的科学基础和技术支持.本文采用了电化学测量、CuK-边和PtL3-边的原位同步辐射X射线吸收光谱(XAS)测试以及密度泛函理论(DFT)计算相结合的方法,系统地研究了高熵合金电催化剂PtPdRhRuCu/C的析氢反应(HER)活性、反应机制以及结构演变规律.PtPdRhRuCu HEAs纳米颗粒由简便的一步溶剂热法制备,直径约为6.7±0.6 nm,其合金结构和元素分布通过多种表征手段(扫描透射电子显微镜、X射线衍射和能量色散X射线光谱等)得到确认.XAS对Cu K-边和PtL3-边的分析结果显示,HEAs纳米颗粒表面的少量铜氧化物在HER过程中被还原至金属态.扩展X射线吸收精细结构的拟合结果表明,HEAs在工况HER中保持了金属态和无序的原子排列,没有新的分离相形成.电化学测试结果表明,得益于多金属活性位点,PtPdRhRuCu/C催化剂在酸性和碱性条件下均表现出较好的HER活性和耐久性.在10 m Acm^(-2)的电流密度下,该催化剂在1molL^(-1)KOH中具有23.3 m V的极低过电位,优于商业Pt/C催化剂(50.3 m V),其质量活性是Pt/C的7.9倍,达到3.0 Amg^(-1)Pt.PtPdRhRuCu的高熵效应显著提升了催化剂在HER中的长期稳定性,在稳定性测试中,PtPdRhRuCu/C催化剂在10000次循环伏安测试后几乎无性能衰减,而Pt/C的过电位增加了约24 m V.在-55 m V过电位下的30 h的HER测试中,PtPdRhRuCu/C保持95.7%的初始电流密度,而Pt/C衰减了53.6%.在酸性条件下,PtPdRhRuCu/C的循环稳定性和耐久性也优于Pt/C.DFT计算结果表明,PtPdRhRuCu/C较好的HER性能和稳定性归因于高熵合金的协同效应,多金属成分提供了多样的活性位点,优化了HER反应路径,特别是在Volmer步骤中降低了水裂解的反应能垒.PtPdRhRuCu/C上的HER过程遵循Volmer-Tafel机理,水分子优先吸附在Ru位点,促进HO-H键的解离,解离出的质子迁移到Pt上,而OH通过Ru和Rh的桥接作用而稳定,最终在Cu上释放H2.综上,本文展示了高熵合金在HER中较好的性能,并通过详细的表征深入理解了其构-效关系.研究成果为高熵合金催化剂的合理设计和应用提供理论支持,为未来高效、耐久和低成本的绿色制氢技术提供重要的科学依据和技术支持.

碱性聚合物电解质膜的表面锥形阵列结构提升燃料电池性能

燃料电池作为一种清洁高效的能量转换装置,被认为是构建未来社会可再生能源结构的关键一环。不同于质子交换膜燃料电池(PEMFC),碱性聚合物电解质燃料电池(APEFC)的出现使非贵金属催化剂的使用成为可能,因而受到了日益广泛的关注和研究。APEFC的关键结构是膜电极,主要由聚合物电解质膜和阴阳极(含催化层、气体扩散层)组成,膜电极是电化学反应发生的场所,其优劣直接决定着电池性能的好坏。因此,基于现有的碱性聚合物电解质及催化剂体系,如何构筑更加优化的膜电极结构,使APEFC发挥出更高的电池性能是亟待开展的研究。本文首先通过模板法在碱性聚合物电解质膜的表面构建出有序的锥形阵列,再将具有阵列结构的一侧作为阴极来构筑膜电极,同时,作为对比,制备了由无阵列结构的聚合物电解质膜构筑而成的膜电极,最后对基于两种不同膜电极的APEFC的电化学性能进行了对比研究。实验结果表明,锥形阵列结构可以将APEFC的峰值功率密度由1.04 W·cm^(−2)显著提高到1.48 W·cm^(−2),这主要归因于在APEFC的阴极侧具有锥形阵列结构的聚合物电解质膜的亲水性的提升和催化剂电化学活性面积的增加。本工作为碱性聚合物电解质燃料电池的膜电极结构设计与优化提供了新思路。

Engineering Pt heterogeneous catalysts for accelerated liquid–solid redox conversion in Li-S batteries

The shuttle effect caused by soluble lithium polysulfides (LiPSs) deteriorates multiphase transformation reaction kinetics of sulfur species,and gives rise to an unserviceable lithium-sulfur (Li-S) battery.Catalysis,as a process optimization approach,offers an option to eliminate the intrinsic issues.However,exploring and understanding the role of catalysts on electrode reaction remains critical bottlenecks,particularly as they are prone to continuous evolution under complex dynamic environment.Herein,platinum nanoparticles loaded on MXene nanosheets,as sulfur host,and the action of catalysts on the reaction process are investigated via ex-situ monitors upon solid–liquid–solid chemical transformation of sulfur species.These traces confirm that the high performance originates from electron transfer between catalysts and LiPSs,which lowers the nucleation barrier from liquid LiPSs to solid Li_(2)S/Li_(2)S_(2).Further,the accelerated liquid–solid conversion can alleviate the accumulation of LiPSs,and boost the reaction kinetics in Li-S batteries.The findings corroborate the electronic modulation between catalysts and LiPSs,which is a generalizable strategy to optimize energy conversion efficiency of Li-S batteries.

Features of different types of seismic events in China’s Capital Region

Seismic records produced by different seismic sources vary.In this study,we compared the waveform records and time-frequency characteristics of tectonic earthquakes,artificial explosions,and mine collapses in China’s Capital Region.The results show that tectonic earthquakes are characterized by stronger S-wave energy than P-wave energy,obvious high-frequency components,and wide frequency bands of P and S waves.Artificial explosions are characterized by greater P-wave amplitude than S-wave amplitude and near-station surface wave development.Mine collapses are characterized by lower overall frequency,more obvious surface waves,and longer duration.We extracted quantitative discriminants based on the analysis of different event records,with 31 feature values in 7 categories(P/S maximum amplitude ratio,high/low frequency energy ratio,P/S spectral ratio,corner frequency,duration,the second-order moment of spectrum,and energy strongest point).A comparison of the ability of these feature values to recognize distinct events showed that the 6-17 Hz P/S spectral ratio was able to completely distinguish artificial explosions from the other two types of events.The S-wave corner frequency performed relatively well in identifying all three types of events,with an accuracy of over 90%.Additionally,a support vector machine was used to comprehensively distinguish multiple features,with an accuracy for all three types of events reaching up to 100%.

PtRuAgCoNi高熵合金纳米颗粒高效电催化氧化5-羟甲基糠醛

5-羟甲基糠醛(HMF)的电催化氧化被认为是合成2,5-呋喃二甲酸(FDCA)最环保、经济和有效的方法之一,它可作为聚呋喃二甲酸乙二醇酯(PEF)的生物基前体。在这项工作中,我们通过低温溶剂热法合成了PtRuAgCoNi高熵合金纳米颗粒,并在不改变颗粒结构和组成的情况下进行了简易的处理以去除表面活性剂。负载在碳载体上的合金纳米催化剂无论是否含有表面活性剂在HMF电催化氧化为FDCA的过程中都表现出比商业Pt/C更好的催化性能。且表面活性剂的去除可以进一步提高其电催化性能,表明高熵合金纳米粒子在电催化和绿色化学中具有广阔的应用前景。

KCNJ15 deficiency promotes drug resistance via affecting the function of lysosomes

The altered lysosomal function can induce drug redistribution which leads to drug resistance and poor prognosis for cancer patients.V-ATPase,an ATP-driven proton pump positioned at lysosomal surfaces,is responsible for maintaining the stability of lysosome.Herein,we reported that the potassium voltage-gated channel subfamily J member 15(KCNJ15)protein,which may bind to V-ATPase,can regulate the function of lysosome.The deficiency of KCNJ15 protein in breast cancer cells led to drug aggregation as well as reduction of drug efficacy.The application of the V-ATPase inhibitor could inhibit the binding between KCNJ15 and V-ATPase,contributing to the amelioration of drug resistance.Clinical data analysis revealed that KCNJ15 deficiency was associated with higher histological grading,advanced stages,more metastases of lymph nodes,and shorter disease free survival of patients with breast cancer.KCNJ15 expression level is positively correlated with a high response rate after receiving neoadjuvant chemotherapy.Moreover,we revealed that the small molecule drug CMA/BAF can reverse drug resistance by disrupting the interaction between KCNJ15 and lysosomes.In conclusion,KCNJ15 could be identified as an underlying indicator for drug resistance and survival of breast cancer,which might guide the choice of therapeutic strategies.

CO_(2)electrolysis:Advances and challenges in electrocatalyst engineering and reactor design

Electrochemical reduction of CO_(2)(CO_(2)RR)coupled with renewable electrical energy is an attractive way of upgrading CO_(2)to value-added chemicals and closing the carbon cycle.However,CO_(2)RR electrocatalysts still suffer from high overpotential,and the complex reaction pathways of CO_(2)RR often lead to mixed products.Early research focuses on tuning the binding of reaction intermediates on electrocatalysts,and recent efforts have revealed that the design of electrolysis reactors is equally important for efficient and selective CO_(2)RR.In this review,we present an overview of recent advances and challenges toward achieving high activity and high selectivity in CO_(2)RR at ambient conditions,with a particular focus on the progress of CO_(2)RR electrocatalyst engineering and reactor design.Our discussion begins with three types of electrocatalysts for CO_(2)RR(noble metalbased,none-noble metal-based,and metal-free electrocatalysts),and then we examine systems-level strategies toward engineering specific components of the electrolyzer,including gas diffusion electrodes,electrolytes,and polymer electrolyte membranes.We close with future perspectives on catalyst development,in-situ/operando characterization,and electrolyzer performance evaluation in CO_(2)RR studies.

不具有稳定性质的4-一致超图族献给刘桂真教授80寿辰

不同于图的情形,对于正整数r≥3和一些经典的r-一致超图族M,顶点数固定条件下边数最多的不含M的r-一致超图(称为M的极图)可能不止一个,而且这些超图在距离上相距较远,这种现象被称为不稳定性,也是确定此类超图Turán数的基本障碍.Liu和Mubayi(2022)给出了第一个具有不稳定性的3-一致超图族的例子.对于r≥4,通过具有不稳定性的3-一致超图族可以构造具有同样性质的r-一致超图族.本文构造第一个不依赖于3-一致超图的4-一致超图族M,使得M有两个在距离上相距较远的极图.同时,本文证明相应的Andrásfai-Erd?os-Sós型稳定性定理:任意最小度接近于极图平均度的不含M的4-一致超图一定是这两个极图中一个的子图.此外,作为本文结果的推论,本文还证明了M的可行域具有两个最大值点.

全固态电池的研究进展与挑战——以表征技术和理论机制的突破推动全固态电池的原始创新

全固态电池作为新一代高能量密度电池的重要发展方向,是能源结构转型的重要支撑。全球各国相继提出固态电池重大科技计划以及规模化生产时间线,竞争趋向白热化。本文梳理了学术与产业界、国内与国外的研究现状,并依据现代交通全面电动化的发展趋势提出了全固态电池的关键性能指标。基于此,本文凝炼了全固态电池发展面临的重要科学问题:固态电解质中的离子输运机制、全固态电池中的锂枝晶生长机制以及多场耦合下的失效、失控机制。未来,建议通过先进表征技术的发展深入理解全固态电池新体系中的基础科学问题,实现理论机制的突破;进而指导关键材料创制,推动全固态电池原始创新,实现我国从二次电池技术的跟跑者到领跑者的跨越式发展。

Moisture stable and ultrahigh-rate Ni/Mn-based sodium-ion battery cathodes via K^(+)decoration

As one of the most promising cathodes for sodium-ion batteries(SIBs),the layered transition metal oxides have attracted great attentions due to their high specific capacities and facile synthesis.However,their applications are still hindered by the problems of poor moisture stability and sluggish Na^(+)diffusion caused by intrinsic structural Jahn–Teller distortion.Herein,we demonstrate a new approach to settle the above issues through introducing K^(+)into the structures of Ni/Mn-based materials.The physicochemical characterizations reveal that K^(+)induces atomic surface reorganization to form the birnessite-type K_(2)Mn_(4)O_(8).Combining with the phosphate,the mixed coating layer protects the cathodes from moisture and hinders metal dissolution into the electrolyte effectively.Simultaneously,K^(+)substitution at Na site in the bulk structure can not only widen the lattice-spacing for favoring Na^(+)diffusion,but also work as the rivet to restrain the grain crack upon cycling.The as achieved K^(+)-decorated P2-Na_(0.67)Mn_(0.75)Ni_(0.2)5O_(2)(NKMNO@KM/KP)cathodes are tested in both coin cell and pouch cell configurations using Na metal or hard carbon(HC)as anodes.Impressively,the NKMNO@KM/KP||Na half-cell demonstrates a high rate performance of 50 C and outstanding cycling performance of 90.1%capacity retention after 100 cycles at 5 C.Furthermore,the NKMNO@KM/KP||HC fullcell performed a promising energy density of 213.9 Wh·kg^(−1).This performance significantly outperforms most reported state-ofthe-art values.Additionally,by adopting this strategy on O3-NaMn_(0.5)Ni_(0.5)O_(2),we further proved the universality of this method on layered cathodes for SIBs.

A lake ice phenology dataset for the Northern Hemisphere based on passive microwave remote sensing

Lake ice phenology(LIP)is an essential indicator of climate change and helps with understanding of the regional characteristics of climate change impacts.Ground observation records and remote sensing retrieval products of lake ice phenology are abundant for Europe,North America,and the Tibetan Plateau,but there is a lack of data for inner Eurasia.In this work,enhanced-resolution passive microwave satellite data(PMW)were used to investigate the Northern Hemisphere Lake Ice Phenology(PMW LIP).The Freeze Onset(FO),Complete Ice Cover(CIC),Melt Onset(MO),and Complete Ice Free(CIF)dates were derived for 753 lakes,including 409 lakes for which ice phenology retrievals were available for the period 1978 to 2020 and 344 lakes for which these were available for 2002 to 2020.Verification of the PMW LIP using ground records gave correlation coefficients of 0.93 and 0.84 for CIC and CIF,respectively,and the corresponding values of the RMSE were 11.84 and 10.07 days.The lake ice phenology in this dataset was significantly correlated(P<0.001)with that obtained from Moderate Resolution Imaging Spectroradiometer(MODIS)data-the average correlation coefficient was 0.90 and the average RMSE was 7.87 days.The minimum RMSE was 4.39 days for CIF.The PMW is not affected by the weather or the amount of sunlight and thus provides more reliable data about the freezing and thawing process information than MODIS observations.The PMW LIP dataset pro-vides the basic freeze-thaw data that is required for research into lake ice and the impact of climate change in the cold regions of the Northern Hemisphere.The dataset is available at http://www.doi.org/10.11922/sciencedb.j00076.00081.

A cell wall invertase modulates resistance to fusarium crown rot and sharp eyespot in common wheat

Fusarium crown rot(FCR) and sharp eyespot(SE)are serious soil-borne diseases in wheat and its relatives that have been reported to cause wheat yield losses in many areas. In this study, the expression of a cell wall invertase gene, TaCWI-B1,was identified to be associated with FCR resistance through a combination of bulk segregant RNA sequencing and genome resequencing in a recombinant inbred line population. Two biparental populations were developed to further verify TaCWI-B1 association with FCR resistance.Overexpression lines and ethyl methanesulfonate(EMS) mutants revealed TaCWI-B1 positively regulating FCR resistance. Determination of cell wall thickness and components showed that the TaCWI-B1-overexpression lines exhibited considerably increased thickness and pectin and cellulose contents. Furthermore, we found that TaCWI-B1 directly interacted with an alphagalactosidase(TaGAL). EMS mutants showed that TaGAL negatively modulated FCR resistance. The expression of TaGAL is negatively correlated with TaCWI-B1 levels, thus may reduce mannan degradation in the cell wall, consequently leading to thickening of the cell wall. Additionally, TaCWI-B1-overexpression lines and TaGAL mutants showed higher resistance to SE;however, TaCWI-B1 mutants were more susceptible to SE than controls.This study provides insights into a FCR and SE resistance gene to combat soil-borne diseases in common wheat.

Cryo-EM structure of Mycobacterium smegmatis ribosome reveals two unidentified ribosomal proteins close to the functional centers

Dear Editor, Mycobacterium smegmatis is commonly used as a labora- tory surrogate in studying the physiology and pathogenesis of disease-causing mycobacteria, including Mycobacterium tuberculosis, which causes tuberculosis （TB） in human.

Atomic-resolution characterization on the structure of strontium doped barium titanate nanoparticles

Ferroelectric barium titanate nanoparticles(BTO NPs)may play critical roles in miniaturized passive electronic devices such as multi-layered ceramic capacitors.While increasing experimental and theoretical understandings on the structure of BTO and doped BTO have been developed over the past decade,the majority of the investigation was carried out in thin-film materials;therefore,the doping effect on nanoparticles remains unclear.Especially,doping-induced local composition and structure fluctuation across single nanoparticles have yet to be unveiled.In this work,we use electron microscopy-based techniques including high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM),integrated differential phase contrast(iDPC)-STEM,and energy dispersive X-ray spectroscopy(EDX)mapping to reveal atomically resolved chemical and crystal structure of BTO and strontium doped BTO nanoparticles.Powder X-ray diffraction(PXRD)results indicate that the increasing strontium doping causes a structural transition from tetragonal to cubic phase,but the microscopic data validate substantial compositional and microstructural inhomogeneities in strontium doped BTO nanoparticles.Our work provides new insights into the structure of doped BTO NPs and will facilitate the materials design for next-generation high-density nano-dielectric devices.

Enhancing the performances of all-small-molecule ternary organic solar cells via achieving optimized morphology and 3D charge pathways

With the emergence of non-fullerene acceptors(NFAs),the power conversion efficiencies(PCEs)of allsmall-molecule organic solar cells(ASM-OSCs)have been significantly improved.However,due to the strong crystallinities of small molecules,it is much more challenging to obtain the ideal phase separation morphology and efficient charge transport pathways for ASM-OSCs.Here,a high-efficiency ternary ASMOSC has been successfully constructed based on H11/IDIC-4 F system by introduction of IDIC with a similar backbone as IDIC-4F but weak crystallinity.Notably,the addition of IDIC has effectively suppressed large-scale phase aggregation and optimized the morphology of the blend film.More importantly,the molecular orientation has also been significantly adjusted,and a mixed face-on and edge-on orientation has formed,thus establishing a more favorable three-dimensional(3D)charge pathways in the active layer.With these improvements,the enhanced short-circuit current density(JSC)and fill factor(FF)of the ternary system have been achieved.In addition,because of the high lowest unoccupied molecular orbital(LUMO)energy level of IDIC as well as the alloyed structure of the IDIC and IDIC-4F,the promoted open circuit voltage(VOC)of the ternary system has also been realized.

Structural insights into the assembly of the 30S ribosomal subunit in vivo： functional role of S5 and location of the 17S rRNA precursor sequence

The in vivo assembly of ribosomal subunits is a highly complex process, with a tight coordination between protein assembly and rRNA maturation events, such as folding and processing of rRNA precursors, as well as modifications of selected bases. In the cell, a large number of factors are required to ensure the efficiency and fidelity of subunit production. Here we characterize the immature 30S subunits accumulated in a factor-null Escherichia coil strain （ArsgAArbfA）. The immature 30S subunits isolated with varying salt concentrations in the buffer system show interesting differences on both protein composition and structure. Specifically, inter- mediates derived under the two contrasting salt condi- tions （high and low） likely reflect two distinctive assembly stages, the relatively early and late stages of the 3＇ domain assembly, respectively. Detailed structural analysis demonstrates a mechanistic coupling between the maturation of the 5＇ end of the 17S rRNA and the assembly of the 30S head domain, and attributes a unique role of S5 in coordinating these two events. Furthermore, our structural results likely reveal thelocation of the unprocessed terminal sequences of the 17S rRNA, and suggest that the maturation events of the 17S rRNA could be employed as quality control mech- anisms on subunit production and protein translation.

Structural dynamics of the yeast Shwachman- Diamond syndrome protein （Sdol） on the ribosome and its implication in the 60S subunit maturation

The human Shwachman-Diamond syndrome （SDS） is an autosomal recessive disease caused by mutations in a highly conserved ribosome assembly factor SBDS. The functional role of SBDS is to cooperate with another assembly factor, elongation factor l-like （Eft1）, to pro- mote the release of eukaryotic initiation factor 6 （elF6） from the late-stage cytoplasmic 60S precursors. In the present work, we characterized, both biochemically and structurally, the interaction between the 60S subunit and SBDS protein （Sdolp） from yeast. Our data show that Sdolp interacts tightly with the mature 60S subunit in vitro through its domain I and II, and is capable of bridging two 60S subunits to form a stable 2：2 dimer. Structural analysis indicates that Sdolp bind to the ribosomal P-site, in the proximity of uL16 and uL5, and with direct contact to H69 and H38. The dynamic nature of Sdolp on the 60S subunit, together with its strategic binding position, suggests a surveillance role of Sdolp in monitoring the conformational maturation of the ribosomal P-site. Altogether, our data support a con- formational signal-relay cascade during late-stage 60S maturation, involving uL16, Sdolp, and Efllp, which interrogates the functional P-site to control the departure of the anti-association factor elF6.

A binding-block ion selective mechanism revealed by a Na/K selective channel

Mechanosensitive （MS） channels are extensively stud- ied membrane protein for maintaining intracellular homeostasis through translocating solutes and ions across the membrane, but its mechanisms of channel gating and ion selectivity are largely unknown. Here, we identified the Ynal channel as the Na^＋/K^＋ cation-selec- tive MS channel and solved its structure at 3.8 A by cryo- EM single-particle method. Ynal exhibits low conduc- tance among the family of MS channels in E. coil, and shares a similar overall heptamer structure fold with previously studied MscS channels. By combining structural based mutagenesis, quantum mechanical and electrophysiological characterizations, we revealed that ion selective filter formed by seven hydrophobic methionine （Ynal^Met158） in the transmembrane pore determined ion selectivity, and both ion selectivity and gating of Ynal channel were affected by accompanying anions in solution. Further quantum simulation and functional validation support that the distinct binding energies with various anions to Ynal^Met158 facilitate Na^＋/K^＋ pass through, which was defined as binding-block mechanism. Our structural and functional studies provided a new perspective for understanding the mechanism of how MS channels select ions driven by mechanical force.

Nowcasting China's GDP Using a Bayesian Approach

Real time nowcasting is an assessment of current-quarter GDP from timely released economic and financial series before the GDP figure is disseminated.Providing a reliable current quarter nowcast in real time based on the most recently released economic and financial monthly data is crucial for central banks to make policy decisions and longer-term forecasting exercises.In this study,we use dynamic factor models to bridge monthly information with quarterly GDP and achieve reduction in the dimensionality of the monthly data.We develop a Bayesian approach to provide a way to deal with the unbalanced features of the dataset and to estimate latent common factors.We demonstrate the validity of our approach through simulation studies,and explore the applicability of our approach through an empirical study in nowcasting the China's GDP using 117 monthly data series of several categories in the Chinese market.The simulation studies and empirical study indicate that our Bayesian approach may be a viable option for nowcasting the China's GDP.

Generating non-jumps from a known one

Let r≥2 be an integer.The real numberα∈[0,1)is a jump for r if there exists a constant c>0 such that for any?>0 and any integer m≥r,there exists an integer n_0(ε,m)satisfying any r-uniform graph with n≥n_0(ε,m)vertices and density at leastα+?contains a subgraph with m vertices and density at leastα+c.A result of Erd?s and Simonovits(1966)and Erdos and Stone(1946)implies that everyα∈[0,1)is a jump for r=2.Erdos(1964)asked whether the same is true for r≥3.Frankl and Rodl(1984)gave a negative answer by showing that1-1/(ε^(r-1))is not a jump for r if r 3 and l>2r.After that,more non-jumps are found by using a method of Frankl and R?dl(1984).Motivated by an idea of Liu and Pikhurko(2023),in this paper,we show a method to construct maps f:[0,1)→[0,1)that preserve non-jumps,i.e.,ifαis a non-jump for r given by the method of Frankl and Rodl(1984),then f(α)is also a non-jump for r.We use these maps to study hypergraph Turán densities and answer a question posed by Grosu(2016).