Construction of smart propellant with multi-morphologies

Smart materials,which exhibit shape memory behavior in response to external stimuli,have shown great potential for use in biomedical applications.In this study,an energetic composite was fabricated using a UV-assisted DIW 3D printing technique and a shape memory material(SMP)as the binder.This composite has the ability to reduce the impact of external factors and adjust gun propellant combustion behavior.The composition and 3D printing process were delineated,while the internal structure and shape memory performance of the composite material were studied.The energetic SMP composite exhibits an angle of reversal of 18 s at 70°,with a maximum elongation typically reaching up to 280% of the original length and a recovery length of approximately 105%during ten cycles.Additionally,thermal decomposition and combustion behavior were also demonstrated for the energetic SMP composite.

节能领域的助推干预效果——基于现场实验类研究的荟萃分析

助推干预由于低成本、运用简便,近年来被广泛应用于节能领域,然而这种方法的有效性在学界存在分歧。据此,研究运用荟萃分析技术,对2008年至2022年发表的55篇中英文实验类研究进行了荟萃分析,旨在探究节能领域助推干预的有效性,并进一步分析可能影响其有效性的潜在变量。研究发现:(1)节能领域的助推具有显著的干预效果,能够减少干预对象的实际能耗。(2)助推策略、干预时长、干预频率对节能领域的助推干预有显著的调节作用,而具体节能领域的调节效应不显著。总体而言,使用反馈的助推策略效果最佳,助推的影响随着干预时长的增加和频率的降低而逐渐减弱。研究不仅回应了学界的争议,厘清了节能领域助推干预效果异质性的主要原因,研究结论也对节能政策的完善提供了一定的政策启示。

电感耦合等离子体原子发射光谱法用于不锈钢保温杯浸出液中金属离子的测定

设计了一个利用电感耦合等离子体原子发射光谱法(ICP-AES)测定保温杯浸出液中金属离子的本科生仪器分析实验。以保温杯浸出液为检测对象,能极大激发学生实验兴趣,引导学生学以致用并进行深入探究,提高实验操作能力,培养团队协作精神。本实验内容及流程完整,实验试剂及过程安全绿色,实验样品处理快速简便,实验用时合理,适合本科实验教学。

Interaction of moiréexcitons with cavity photons in two-dimensional semiconductor hetero-bilayers

Moirématerials,composed of two single-layer two-dimensional semiconductors,are important because they are good platforms for studying strongly correlated physics.Among them,moirématerials based on transition metal dichalcogenides(TMDs)have been intensively studied.The hetero-bilayer can support moiréinterlayer excitons if there is a small twist angle or small lattice constant difference between the TMDs in the hetero-bilayer and form a type-Ⅱ band alignment.The coupling of moiréinterlayer excitons to cavity modes can induce exotic phenomena.Here,we review recent advances in the coupling of moiréinterlayer excitons to cavities,and comment on the current difficulties and possible future research directions in this field.

紫外光协同磁性离子交换树脂活化过硫酸盐去除水中腐殖酸的效能与机理

采用紫外光协同磁性离子交换树脂活化过硫酸盐去除水中腐殖酸,探究了紫外光/过硫酸盐/磁性离子交换树脂(UV/PMS/MIEX)体系对水中腐殖酸的去除效能、影响腐殖酸去除的环境因素、活性氧化物质产生机理及腐殖酸去除机理。UV/PMS/MIEX体系对水中腐殖酸具有显著的去除效能,反应120 min后去除率可达91.71%。树脂投加量和温度的提高可促进腐殖酸的去除,一定程度上增加PMS浓度可提升腐殖酸的去除效率,而溶液pH对腐殖酸去除的影响不明显。该体系以氧化过程为主,在树脂表面的铁氧化物,含氧官能团及外加紫外光等多种协同作用下,可有效活化过硫酸盐产生·OH, SO_(4)^(·-), O_(2)^(·-)和^(1)O_(2)等多种活性氧化物质,自由基与非自由基途径共同协作降解腐殖酸。MIEX树脂体现出良好的重复使用性能,同时对于体系中的各类副产物可有效吸附去除。本研究为去除水中腐殖酸提供了一种新方法,所构建的氧化体系表现出良好应用前景。

Efficacy and safety of human umbilical cord-derived mesenchymal stem cells in the treatment of refractory immune thrombocytopenia:a prospective,single arm,phase I trial

Patients with refractory immune thrombocytopenia(ITP)frequently encounter substantial bleeding risks and demonstrate limited responsiveness to existing therapies.Umbilical cord-derived mesenchymal stem cells(UC-MSCs)present a promising alternative,capitalizing on their low immunogenicity and potent immunomodulatory effects for treating diverse autoimmune disorders.This prospective phase I trial enrolled eighteen eligible patients to explore the safety and efficacy of UC-MSCs in treating refractory ITP.The research design included administering UC-MSCs at escalating doses of 0.5×10^(6)cells/kg,1.0×10^(6)cells/kg,and 2.0×10^(6)cells/kg weekly for four consecutive weeks across three cohorts during the dose-escalation phase,followed by a dose of 2.0×10^(6)cells/kg weekly for the dose-expansion phase.Adverse events,platelet counts,and changes in peripheral blood immunity were monitored and recorded throughout the administration and follow-up period.Ultimately,12(with an addition of three patients in the 2.0×10^(6)cells/kg group due to dose-limiting toxicity)and six patients were enrolled in the dose-escalation and dose-expansion phase,respectively.Thirteen patients(13/18,72.2%)experienced one or more treatment emergent adverse events.Serious adverse events occurred in four patients(4/18,22.2%),including gastrointestinal hemorrhage(2/4),profuse menstruation(1/4),and acute myocardial infarction(1/4).The response rates were 41.7%in the dose-escalation phase(5/12,two received 1.0×10^(6)cells/kg per week,and three received 2.0×10^(6)cells/kg per week)and 50.0%(3/6)in the dose-expansion phase.The overall response rate was 44.4%(8/18)among all enrolled patients.To sum up,UC-MSCs are effective and well tolerated in treating refractory ITP(ClinicalTrials.gov ID:NCT04014166).

Influence of H_(2)S and NH_(3) on biogas dry reforming using Ni catalyst:a study on single and synergetic effect

Biogas is a renewable biomass energy source mainly composed of CH4 and CO_(2).Dry reforming is a promising technology for the high-value utilization of biogas.Some impurity gases in biogas can not be completely removed after pretreatment,which may affect the performance of dry reforming.In this study,the influence of typical impurities H_(2)S and NH_(3) on dry reforming was studied using Ni/MgO catalyst.The results showed that low concentration of H_(2)S in biogas could cause serious deactivation of catalyst.Characterization results including EDS,XPS and TOF-SIMS confirmed the adsorption of sulfur on the catalyst surface,which was the cause of catalyst poisoning.We used air calcination method to regenerate the sulfur-poisoned catalysts and found that the regeneration temperature higher than 500℃could help catalyst recover the original activity.NH_(3)in the concentration range of 50–10000 ppm showed a slight inhibitory effect on biogas dry reforming.The decline rate of biogas conversion efficiency increased with the increase of NH_(3) concentration.This was related to the reduction of oxygen activity on catalyst surface caused by NH_(3).The synergetic effect of H_(2)S and NH_(3)in biogas was investigated.The results showed that biogas conversion decreased faster under the coexistence of H_(2)S and NH_(3)than under the effect of H_(2)S alone,so as the surface oxygen activity of catalyst.Air calcination regeneration could also recover the activity of the deactivated catalyst under the synergetic effect of H_(2)S and NH_(3).

Deterministic and replaceable transfer of silver flakes for microcavities

How to fabricate high-quality microcavities simply and at low cost without causing damage to environmentally sensitive active layers such as perovskites are crucial for the studies of exciton–polaritons,however,it remains challenging in the field of microcavity fabrication.Usually,once the top mirror is deposited,the detuning of the microcavity is fixed and there is no easy way to tune it.Here,we have developed a method for deterministically transferring silver mirrors,which is relatively simple and guarantees the active layer from damaging of high temperature,particle bombardment,etc.,during the deposition of the top mirror.Furthermore,with the help of a glass probe,we demonstrate a replaceable silver transfer method to tune the detuning of the microcavity,thereby changing the coupling of photons and excitons therein.The developed deterministic and replaceable silver mirror transfer methods will provide the capability to fabricate high-quality and tunable microcavities and play an active role in the development of the exciton–polariton field.

Solvent effects and mass transfer on aroma extraction during solid-state distillation

Steam distillation is an important unit operation to extract valuable compounds from natural solid-state substrates.Solid-state distillation with steam can extract aroma from fermented solid substrate such as fermented grains of Chinese liquor fermentation.However,this procedure is still operated based on generations of empirical skills rather than a technique under process control based on scientific principles.The resulting drawback is poor mass and heat transfer with undesired consequences concerning productivity,quality and sustainability.Mathematical modelling can be a powerful tool to get insight into such an empirical process for potential rational design,optimization and control.Therefore,we established a mathematical model to describe the mass transfer based on kinetic parameters.The simulation results show that the distillation had a natural column plate structure that more effectively concentrated compounds.Furthermore,this structure resulted in a high ethanol concentration in the distillate.To evaluate subsequent effect of high ethanol concentration,we analysed aroma compounds in the distillates under simulated conditions with or without ethanol.The hydrophobic compounds were fitted well under conditions with ethanol,whereas hydrophilic compounds had similar outcomes under both conditions.The results show that ethanol could accelerate the release of hydrophobic compounds in Chinese liquor distillation.Therefore,solvent could be one of the important factors to optimize the distillation process.Our findings provide a reference for improving the extraction during solid-state distillation.

On-Surface Bottom-Up Construction of COF Nanoshells towards Photocatalytic H_(2)Production

The rational design of an outer shell is of great significance to promote the photocatalytic efficiency of core-shell structured photocatalysts.Herein,a covalent organic framework(COF)nanoshell was designed and deposited on the cadmium sulfide(CdS)core surface.A typical COF material,TPPA,featuring exceptional stability,was synthesized through interfacial polymerization using 1,3,5-triformylphloroglucinol(TP)and p-phenylenediamine(PA)as monomers.The nanoshell endows the CdS@TPPA nanosphere with ordered channels for unimpeded light-harvesting and fast diffusion of reactants/products and well-defined modular building blocks for spatially charge separation.Moreover,the heterojunction formed between CdS and TPPA can further facilitate the effective charge separation at the interface via lower exciton binding energy compared with that of pristine TPPA.By modulating the thickness of TPPA nanoshell,the CdS@TPPA nanosphere photocatalyst with the nanoshell thickness of about 8±1 nm exhibits the highest photocatalytic H2 evolution of 194.1μmol h^(-1)(24.3 mmol g^(-1)h^(-1),8 mg),which is superior to most of the reported COF-based photocatalysts.The framework nanoshell in this work may stimulate the thinking about how to design advanced shell architecture in the core-shell structured photocatalysts to achieve coordinated charge and molecule transport.

Durable CRISPR-Based Epigenetic Silencing

Development of CRISPR-based epigenome editing tools is important for the study and engineering of biological behavior.Here,we describe the design of a reporter system for quantifying the ability of CRISPR epigenome editors to produce a stable gene repression.We characterize the dynamics of durable gene silencing and reactivation,as well as the induced epigenetic changes of this system.We report the creation of single-protein CRISPR constructs bearing combinations of three epigenetic editing domains,termed KAL,that can stably repress the gene expression.This system should allow for the development of novel epigenome editing tools which will be useful in a wide array of biological research and engineering applications.