钾改性氧化铝基羰基硫水解催化剂及其失活机理

天然气、油田伴生气、高炉煤气等化工生产过程中伴生COS气体,不仅会腐蚀管道和毒害催化剂,还会严重污染环境并危害人类健康。COS催化水解反应可在温和条件下高效的将COS脱除,是最具应用前景的COS脱除技术之一。碱金属元素因其具有独特的电子供体性质、表面碱性和静电吸附等特性,常被用作助催化剂以提高Al_(2)O_(3)的COS催化水解性能。近年来,以钾为助剂改性的Al_(2)O_(3)催化剂(K_(2)CO_(3)/Al_(2)O_(3))在COS催化水解反应中得到广泛的应用,但由于负载在Al_(2)O_(3)上的K物种的组成复杂,目前研究者对K_(2)CO_(3)/Al_(2)O_(3)催化剂上COS水解机理的理解仍存在一定的困惑和争议。本论文通过湿法浸渍法合成出一系列钾盐和钠盐改性的Al_(2)O_(3)催化剂,并利用各类先进的表征技术对这些催化剂进行分析。活性测试表明,以K_(2)CO_(3)、K_(2)C_(2)O_(4)、NaHCO_(3)、Na_(2)CO_(3)和NaC2O4改性Al_(2)O_(3)催化剂均有助于COS的水解。其中K_(2)CO_(3)/Al_(2)O_(3)拥有最佳的COS水解性能,连续运行20 h后其COS转化率仍高于~93%,远远优于未改性的Al_(2)O_(3)(~58%)。我们利用原位红外光谱和X射线光电子能谱探明了反应过程中催化剂的化学结构特征,阐明了H_(2)O分子在K_(2)CO_(3)/Al_(2)O_(3)上的水解作用机制。原位红外表明COS在K_(2)CO_(3)/Al_(2)O_(3)上的水解过程中形成了硫代碳酸氢盐中间产物。X射线光电子能谱表征证明催化剂的失活主要是因为催化剂表面积累了硫酸盐和单质硫。此外,我们还研究了水蒸气含量对COS水解性能的影响,研究发现,由于H_(2)O和COS分子在催化剂表面存在竞争吸附,过量的H_(2)O会引起催化活性的下降。上述研究表明,K_(2)CO_(3)/Al_(2)O_(3)催化剂上COS水解性能的提高主要是形成了HO-Al-O-K界面活性位。更为重要的是,所制备的催化剂都是在模拟工业工况条件下进行的,这为后续的工业应用提供了宝贵理论指导。本工作为理解助剂钾在Al_(2)O_(3)催化剂上COS水解活性的增强提供了新的见解,这为未来设计稳定高效的COS水解催化剂打开了新的发展方向。

Repetitive transcranial magnetic stimulation for hallucination in schizophrenia spectrum disorders A meta-analysis

OBJECTIVE： This study assessed the efficacy and tolerability of repetitive transcranial magnetic stimulation for treatment of auditory hallucination of patients with schizophrenia spectrum disorders. DATA SOURCES： Online literature retrieval was conducted using PubMed, ISI Web of Science, EMBASE, Medline and Cochrane Central Register of Controlled Trials databases from January 1985 to May 2012. Key words were ＂transcranial magnetic stimulation＂, ＂TMS＂, ＂repetitive tran- scranial magnetic stimulation＂, and ＂hallucination＂. STUDY SELECTION： Selected studies were randomized controlled trials assessing therapeutic ef- ficacy of repetitive transcranial magnetic stimulation for hallucination in patients with schizophrenia spectrum disorders. Experimental intervention was low-frequency repetitive transcranial magnetic stimulation in left temporoparietal cortex for treatment of auditory hallucination in schizophrenia spectrum disorders. Control groups received sham stimulation. MAIN OUTCOME MEASURES： The primary outcome was total scores of Auditory Hallucinations Rating Scale, Auditory Hallucination Subscale of Psychotic Symptom Rating Scale, Positive and Negative Symptom Scale-Auditory Hallucination item, and Hallucination Change Scale. Secondary outcomes included response rate, global mental state, adverse effects and cognitive function. RESULTS： Seventeen studies addressing repetitive transcranial magnetic stimulation for treatment of schizophrenia spectrum disorders were screened, with controls receiving sham stimulation. All data were completely effective, involving 398 patients. Overall mean weighted effect size for repeti- tive transcranial magnetic stimulation versus sham stimulation was statistically significant （MD = -0.42, 95%C/： -0.64 to -0.20, P = 0.000 2）. Patients receiving repetitive transcranial magnetic stimulation responded more frequently than sham stimulation （OR = 2.94, 95%C/： 1.39 to 6.24, P =0.005）. No significant differences were found between active repetitive transcranial magnetic stimulation and sham stimulation for positive or negative symptoms. Compared with sham stimulation, active repeti- tive transcranial magnetic stimulation had equivocal outcome in cognitive function and commonly caused headache and facial muscle twitching. CONCLUSION： Repetitive transcranial magnetic stimulation is a safe and effective treatment for auditory hallucination in schizophrenia spectrum disorders,

Morphology evolution of acetic acid-modulated MIL-53(Fe)for efficient selective oxidation of H2S

MIL-53(Fe)was synthesized using a“modulator approach”that utilizes acetic acid(HAc)as an additive to control the size and morphology of the resulting crystals.We demonstrate that after activation under vaccum at 100℃,the MIL-53(Fe)functions well for H2S selective oxidation.The introduction of acetic acid in the presence of benzene-1,4-dicarboxylic acid(H2BDC)would result in a series of MIL-53(Fe)nanocrystals(denoted as MIL-53(Fe)-xH,x stands for the volume of added HAc with morphology evoluting from irregular particles to short hexagonal columns.The vacuum treatment facilitates the removal of acetate groups,thus generating Fe3+Lewis acid sites.Consequently,the resulted MIL-53(Fe)-xH exhibits good catalytic activity(98%H2S conversion and 92%sulfur selectivity)at moderate reaction temperatures(100–190℃).The MIL-53(Fe)-5H is superior to the traditional iron-based catalysts,showing stable performance in a test period of 55 h.

Tuning the growth of Cu-MOFs for efficient catalytic hydrolysis of carbonyl sulfide

Development of the high activity,promoter‐free catalysts for carbonyl sulfide(COS)hydrolysis is important for the efficient utilization of various feedstocks.In this study,the Cu‐based metal‐organic framework HKUST‐1is synthesized by a simple and mild anodic‐dissolution electrochemical method.The physical and chemical properties of the samples are characterized by several techniques,including scanning electron microscopy,X‐ray diffraction,Brunauer‐Emmett‐Teller analysis and X‐ray photoelectron spectroscopy.The results reveal that the synthesis voltage plays a crucial role in controlling the morphology of the resulting HKUST‐1.The obtained samples function as novel catalysts for the hydrolysis of COS.A high efficiency,approaching100%,can be achieved for the conversion of COS at150oC over the optimal HKUST‐1synthesized at25V.This is significantly higher than that of the sample prepared by the traditional hydrothermal method.Additionally,the effects of the water temperature and the flow velocity on the hydrolysis of COS are also investigated in detail.Finally,a possible reaction pathway of COS hydrolysis over HKUST‐1is also proposed.This work represents the first example of MOFs applied to the catalytic hydrolysis of COS.The results presented in this study can be anticipated to give a feasible impetus to design novel catalysts for removing the sulfur‐containing compounds.

Chemometric identification of canonical metabolites linking critical process parameters to monoclonal antibody production during bioprocess development

A deeper understanding of the biological events occurring when bioprocess parameters changed will be of great value in improving the monoclonal antibodies (mAbs) production. Design of experiment (DoE) was applied to investigate the effect of process parameters (pH, temperature shift and dissolve oxygen (DO)) on protein titer. The key metabolites connecting the critical process parameters (CPPs) with monoclonal antibody production were identified by different chemometrics tools. Finally, the biological events of marker metabolites relating with titer improvement were concluded. pH and temperature shift were identified as CPPs that affect the target protein titer. A series of metabolites influenced by the altered CPPs and correlated with protein titer were screened by principal component analysis (PCA) and Pearson' correlation test. The marker metabolites and their pathways linking CPPs to target protein titer in different culture phases were summarized. Metabolomics and chemometrics are promising data-driven tools to shine light into the biological black box between the bioprocess parameters and process performance.

Cobalt-Based Cocatalysts for Photocatalytic CO_(2)Reduction

Conversion of carbon dioxide(CO_(2))into valuable chemicals and renewable fuels via photocatalysis represents an eco-friendly route to achieve the goal of carbon neutralization.Although various types of semiconductor materials have been intensively explored,some severe issues,such as rapid charge recombination and sluggish redox reaction kinetics,remain.In this regard,cocatalyst modifi cation by trapping charges and boosting surface reactions is one of the most effi cient strategies to improve the effi ciency of semiconductor photocatalysts.This review focuses on recent advances in CO_(2)photoreduction over costeff ective and earth-abundant cobalt(Co)-based cocatalysts,which are competitive candidates of noble metals for practical applications.First,the functions of Co-based cocatalysts for promoting photocatalytic CO_(2)reduction are briefl y discussed.Then,diff erent kinds of Co-based cocatalysts,including cobalt oxides and hydroxides,cobalt nitrides and phosphides,cobalt sulfi des and selenides,Co single-atom,and Co-based metal–organic frameworks(MOFs),are summarized.The underlying mechanisms of these Co-based cocatalysts for facilitating CO_(2)adsorption–activation,boosting charge separation,and modulating intermediate formation are discussed in detail based on experimental characterizations and density functional theory calculations.In addition,the suppression of the competing hydrogen evolution reaction using Co-based cocatalysts to promote the product selectivity of CO_(2)reduction is highlighted in some selected examples.Finally,the challenges and future perspectives on constructing more effi cient Co-based cocatalysts for practical applications are proposed.

Resilience indices from a family of recovery functions

Defining and measuring resilience using a unified framework has been a topic of intense research.This article presents a perspective on how resilience could be quantitatively assessed through a set of indices.It starts with a brief explanation of resilience in the context of supply chain and a quick summary of existing quantitative measures of resilience.It then discusses how resilience could be quantified in a constructive manner so that the resulting metrics are representative of the performance throughout the system's life cycle.In particular,it is proposed that resilience should be evaluated according to different time periods,i.e.before,during and after a disruption has occurred.Four dimensions of resilience,namely reliability,robustness,recovery and reconfigurability,can then be used to make up a set of indices for resilience.For numerical illustration,these indices are computed based on recovery data arising from Hurricane Sandy in October 2012.Finally,it is postulated that resilience will be the performance metric that complements productivity and sustainability as the third pillar for measuring success of organizations,and in turn,that of sovereign countries in their quests for developing smart cities.

Size distributions of aerosol and water-soluble ions in Nanjing during a crop residual burning event

To investigate the impact on urban air pollution by crop residual burning outside Nanjing, aerosol concentration, pollution gas concentration, mass concentration, and water-soluble ion size distribution were observed during one event of November 4-9, 2010. Results show that the size distribution of aerosol concentration is bimodal on pollution days and normal days, with peak values at 60- 70 and 200-300 nm, respectively. Aerosol concentration is 104 cm-3.nm-1 on pollution days. The peak value of spectrum distribution of aerosol concentration on pollution days is 1.5-3.3 times higher than that on a normal day. Crop residual burning has a great impact on the concentration of fine particles. Diurnal variation of aerosol concentration is trimodal on pollution days and normal days, with peak values at 03：00, 09：00 and 19：00 local standard time. The first peak is impacted by meteorological elements, while the second and third peaks are due to human activities, such as rush hour traffic. Crop residual burning has the greatest impact on SO2 concentration, followed by NO2, 03 is hardly affected. The impact of crop residual burning on fine particles （〈 2.1 μm） is larger than on coarse particles （〉 2.1 μm）, thus ion concentration in fine particles is higher than that in coarse particles. Crop residual burning leads to similar increase in all ion components, thus it has a small impact on the water-soluble ions order. Crop residual burning has a strong impact on the size distribution of K^＋, Cl^-, Na^＋, and F- and has a weak impact on the size distributions of NH4^＋, Ca^2＋, NO3^- and SO4^2-.

Annual variations of black carbon over the Yangtze River Delta from 2015 to 2018

In this study,the black carbon (BC) measurements in the atmosphere of Nanjing,China were continuously conducted from 2015 to 2018 using a Model AE-33 aethalometer.By combining dataset of PM_(2.5),PM_(10),CO,NO_2,SO_2,O_3 and meteorological parameters,the temporal variations and the source apportionment of BC were given in this study.The results showed that the PM_(2.5) mass concentrations decreased in Nanjing,with an average annual rate of variation of 6.50μg/(m^3·year).Differently,the annual average concentrations of BC increased with an average annual variation rate of 214.71 ng/(m^3·year).The seasonal variations showed the pattern of BC mass concentrations in winter>autumn>spring>summer.The diurnal variations of BC mass concentrations showed a double-peak in all four seasons.The first peak occurred at approximately 7:00 in spring,summer and autumn and around 8:00 in winter.The second peak took place after 18:00.The average AAE (absorption ?ngstr?m exponent) was 1.26 with a maximum of 1.35 during wintertime and the lowest(1.12) during summertime.In addition,the AAE was smaller in the daytime than that at night,with a minimum occurring between 13:00 and 14:00.BC and visibility show a good power-function relationship at different humidity levels.The average values of the visibility thresholds of the BC mass concentrations in spring,summer,autumn and winter were 1.326,5.522,1.340 and 0.708μg/m^3,respectively.The greater the relative humidity,the smaller the visibility threshold for the BC mass concentrations was.

Characterization of the aerosol chemical composition during the COVID-19 lockdown period in Suzhou in the Yangtze River Delta,China

To control the spread of COVID-19,rigorous restrictions have been implemented in China,resulting in a great reduction in pollutant emissions.In this study,we evaluated the air quality in the Yangtze River Delta during the COVID-19 lockdown period using satellite and ground-based data,including particle matter(PM),trace gases,water-soluble ions(WSIs) and black carbon(BC).We found that the impacts of lockdown policy on air quality cannot be accurately assessed using MODIS aerosol optical depth(AOD) data,whereas the tropospheric nitrogen dioxide(NO_(2)) vertical column density can well reflect the influences of these restrictions on human activities.Compared to the pre-COVID period,the PM_(2.5),PM_(10),NO_(2),carbon monoxide(CO),BC and WSIs during the lockdown in Suzhou were observed to decrease by 37.2%,38.3%,64.5%,26.1%,53.3% and 58.6%,respectively,while the sulfur dioxide(SO_(2)) and ozone(O_(3)) increased by 1.5% and 104.7%.The WSIs ranked in the order of NO_(3)~->NH_(4)^(+)>SO_(4)^(2-)>Cl~->Ca^(2+)>K^(+)>Mg^(2+)>Na + during the lockdown period.By comparisons with the ion concentrations during the pre-COVID period,we found that the ions NO 3-,NH 4 +,SO_(4)^(2-),Cl~-,Ca^(2+),K^(+) and Na^(+) decreased by 66.3%,48.8%,52.9%,56.9%,57.9% and 76.3%,respectively,during the lockdown,in contrast to Mg^(2+),which increased by 30.2%.The lockdown policy was found to have great impacts on the diurnal variations of Cl~-,SO_(4)^(2-),Na^(+) and Ca^(2+).

Real-time geochemistry of urban aerosol during a heavy dust episode by single-particle aerosol mass spectrometer: Spatio-temporal variability, mixing state and spectral distribution

A heavy dust episode occurred from May 3 to 8,2017 in China,with an influenced area exceeding 1.63 million km2.In this work,the mixing state of aerosols and their spectral distributions were simultaneously observed in the sand source region ofHohhot and the long-range dust transport regi on of Nanji ng by using a single-particle aerosol mass spectrometer(SPAMS).The duration time of this dust episode was 37-40 h in Hohhot and prolonged to 51-104 h in Nanjing.Totals of 336,135(Hohhot)and 235,840(Nanjing)particles in PM2.5 were successfully ionized to identify 10 main particle classes.During this episode,aerosol particles including OCEC(30.65%),K(22.42%),K-CN(17.03%),sodium(9.46%),heavy metal(8.96%),EC-sulfate(3.46%)and Al(3.22%)were prevailing in Hohhot and were dominated by EC-sulfate(22.26%),OCEC(15.21%),heavy metal(11.96%),K(13.68%),sodium(12.27%),Al(10.54%)and EC(9.02%)in Nanjing.The spectral distribution peaked at 0.66μm during the dust episode in Nanjing,0.12μm larger than the peak size in the non-dust episode.Strong signals at-62[NO3)and-61[HCO3]/-61[C5H]for aerosol particles were observed in Hohhot and Nanjing respectively.The proportions of K-CN,sodium,heavy mental,OCEC and EC-sulfate particles in the dust episode of Hohhot were 2.75,1.41,1.80,1.22 and 1.28 times as large as the values in the non-dust episode.For Nanjing,the fractions of EC-sulfate,EC,Al particles in the dust episode were 10.55,4.65 and 1.46 times higher than values in the non-dust episode.The proportions of EC-secondary and EC-nitate particles were found to decrease in the dust episode in the two regions.

Mixing state of individual carbonaceous particles during a severe haze episode in January 2013,Nanjing,China

Chemical composition, hourly counts, and sizes of atmospheric carbonaceous particles were measured to investigate their mixing state on clear and hazy days. 823,122 carbonaceous particles with sizes 0.2-2.0μm was analyzed using a single-particle aerosol mass spectrometer from 1st to 17th January 2013. Particle types included biomass/biofuel burning particles （biomass）, element carbon （EC-dominant） particles that were also mixed with biomass/biofuel burning species （EC-biomass） or secondary species （EC-secondary）, organic carbon （OC）, internally mixed OC and EC （OCEC）, ammonium-containing （ammo- nium） and sodium-containing （sodium） particles. On clear days the top ranked carbonaceous particle types were biomass （48.2%）, EC-biomass （15.7%）, OCEC （11.1%）, and sodium （9.6%）, while on hazy days they were biomass （37.3%）, EC-biomass （17,6%）, EC-secondary （16.6%）, and sodium （12.7%）. The fractions of EC-secondary, ammonium （10%）, and sodium particle types were elevated on hazy days. Numbers of EC-secondary particles were more than four times those on clear days （4.1%）. Thus, carbonaceous particles mixed with ammonium, nitrate and sulfate during aging and transport, enhancing their light extinction effects and hygroscopic growth under high relative humidity on hazy days, further reducing visibility. Our real-time single-particle data showed that changes to mixing state had a significant impact on light extinction during haze events in Nanjing.

Porous α-Fe_(2)O_(3)/SnO_(2) nanoflower with enhanced sulfur selectivity and stability for H_(2)S selective oxidation

Being abundant and active,Fe_(2)O_(3) is suitable for selective oxidation of H_(2)S.However,its practical application is limited due to the poor sulfur selectivity and rapid deactivation.Herein,we report a facile template-free hydrothermal method to fabricate porousα-Fe_(2)O_(3)/SnO_(2) composites with hierarchical nanoflower that can obviously improve the catalytic performance of Fe_(2)O_(3).It was disclosed that the synergistic effect betweenα-Fe_(2)O_(3) and SnO_(2) promotes the physico-chemical properties ofα-Fe_(2)O_(3)/SnO_(2) composites.Specifically,the electron transfer between the Fe^(2+)/Fe^(3+)and Sn^(2+)/Sn^(4+)redox couples enhances the reducibility ofα-Fe_(2)O_(3)/SnO_(2) composites.The number of oxygen vacancies is improved when the Fe cations incorporate into SnO_(2) structure,which facilitates the adsorption and activation of oxygen species.Additionally,the porous structure improves the accessibility of H_(2) S to active sites.Among the composites,Fe1 Sn1 exhibits complete H_(2) S conversion with 100%sulfur selectivity at 220℃,better than those of pureα-Fe_(2)O_(3) and SnO2.Moreover,Fe1 Sn1 catalyst shows high stability and water resistance.

Ultrathin ZnIn_(2)S_(4)Nanosheets-Supported Metallic Ni_(3)FeN for Photocatalytic Coupled Selective Alcohol Oxidation and H_(2)Evolution

Photocatalytic anaerobic organic oxidation coupled with H_(2)evolution represents an advanced solar energy utilization strategy for the coproduction of clean fuel and fine chemicals.To achieve a high conversion efficiency,the smart design of efficient catalysts by the right combination of semiconductor light harvesters and cocatalyst is highly required.Herein,we report a composite photocatalyst composed of noble metal-free transition metal nitride Ni_(3)FeN decorated on 2D ultrathin ZnIn_(2)S_(4)(ZIS)nanosheets for selective oxidation of aromatic alcohols to aldehydes pairing with H_(2)production.In the composite,ultrathin ZIS serves as a light harvester that greatly shortens the diffusion length of photogenerated charges,while the metallic nitride Ni_(3)FeN acts as an advanced cocatalyst which not only captures the photoelectrons generated from the ultrathin ZIS to promote the charge separation,but also provides active sites to lower the overpotential and accelerate the H_(2)reduction.The best photocatalytic performance is found on ZIS/1.5%M-Ni_(3)FeN,which shows a H_(2)generation rate of 2427.9μmol g^(^(-1))h^(-1)and a benzaldehyde(BAD)production rate of 2460μmol g^(-1)h^(-1),about 7.8-fold as high as that of bare ZIS.This work is anticipated to endorse the exploration of transition metal nitrides as high-performance cocatalysts to promote the coupled photocatalytic organic transformation and H_(2)production.

Influence of co-solvent hydroxyl group number on properties of water-based conductive carbon pastes

A series of water-based conductive carbon pastes were prepared by wet ball milling, followed by vacuum defoaming using isopropyl alcohol, propylene glycol or glycerin as co-solvents. Screen printing was then used to prepare conductive patterns. To determine the influence of co-solvent hydroxyl group number on the properties of water-based conductive carbon pastes, the rheological properties of the pastes and the surface morphologies and conductivities of the printed patterns were characterized. The results show that paste viscosity increased with the number of hydroxyl groups and the latter also affected thixotropy. In addition, the boiling points and surface tensions of the co-solvents increased consistently with hydroxyl group number, affecting the hydrodynamic flow. The conductive carbon paste created using propylene glycol as a co-solvent was the best for screen printing because of its weak coffee-ring effect and appro- priate rheological properties, resulting in a smooth coating surface and uniform deposition of the fillers. The resistivity of the pattern printed using paste PG, containing the closest packing of conductive carbon black particles, was 0.44 Ω cm.

Characteristics of black carbon aerosol in Jiaxing,China during autumn 2013

We conducted measurements of black carbon （BC） aerosol in Jiaxing, China during autumn from September 26 to November 30, 2013. We investigated temporal and diurnal variations of BC, and its cor relations with meteorological parameters and other major pollutants. Results showed that hourly mass concentrations of BC ranged from 0.2 to 22.0 μg/m3, with an average of 5.1 μg/ms. The diurnal variation of BC exhibited a bimodal distribution, with peaks at 07：00 and 18：00. The morning peak was larger than the evening peak. The mass percentages of BC in PM2.s and PM10 were 7.1%and 4.8g, respectively. The absorption coefficient of BC was calculated to be 44.4 Mm-1, which accounted for 11.1% of the total aerosol extinction. BC was mainly emitted from local sources in southwestern Jiaxing where BC concentrations were generally greater than 11μg/m3 during the measurement period. Correlation analysis indicated that the main sources of BC were motor vehicle exhaust, and domestic and industrial combustion.

Predicting and overcoming resistance to CDK9 inhibitors for cancer therapy

Abnormally activated CDK9 participates in the super-enhancer mediated transcription of short-lived proteins required for cancer cell survival.Targeting CDK9 has shown potent anti-tumor activity in clinical trials among different cancers.However,the study and knowledge on drug resistance to CDK9 inhibitors are very limited.In this study,we established an AML cell line with acquired resistance to a highly selective CDK9 inhibitor BAY1251152.Through genomic sequencing,we identified in the kinase domain of CDK9 a mutation L156F,which is also a coding SNP in the CDK9 gene.By knocking in L156F into cancer cells using CRISPR/Cas9,we found that single CDK9 L156F could drive the resistance to CDK9 inhibitors,not only ATP competitive inhibitor but also PROTAC degrader.Mechanistically,CDK9 L156F disrupts the binding with inhibitors due to steric hindrance,further,the mutation affects the thermal stability and catalytic activity of CDK9 protein.To overcome the drug resistance mediated by the CDK9-L156F mutation,we discovered a compound,IHMT-CDK9-36 which showed potent inhibition activity both for CDK9 WT and L156F mutant.Together,we report a novel resistance mechanism for CDK9 inhibitors and provide a novel chemical scaffold for the future development of CDK9 inhibitors.

IMPULSIVE CONTROL IN MICROORGANISMS CONTINUOUS FERMENTATION

This work presents the nonlinear dynamical system of continuous fermentation from glycerol to 1,3-propanediol. The impulsive control scheme of continuous culture is intro- duced. By employing impulsive control, Lyapunov＇s method and comparison technique, sufficient conditions are established for the asymptotical stability and synchronization of the dynamical system of continuous fermentation. The upper bound of the impulse interval is also estimated. An example will illustrate the effectiveness of the results in Sec. 4.

An embedded ReS_(2)@MAPbBr_(3) heterostructure with downhill interfacial charge transfer for photocatalytic upgrading of biomass-derived alcohols to aldehydes and H_(2)

Solar-driven selective upgrading of lignocellulosic biomass-derived alcohols to value-added chemicals and clean fuel hydrogen(H_(2))shows great potential for tackling the energy crisis and environmental pollu-tion issues.Here,we construct a MAPbBr_(3)/ReS_(2) heterostructure by embedding distorted tetragonal(1T)phase ReS_(2) nanoflowers into large-sized MAPbBr_(3) for green value-added utilization of biomass-derived alcohols.The embedded structure effectively enlarges the contact interface between the ReS_(2) and the MAPbBr_(3),and importantly,induces a strong built-in electric field aligned between the spatially well-defined MAPbBr_(3) and ReS_(2) nanoflowers.Moreover,the distorted 1T phase ReS_(2) with low work function well matches the energy band of MAPbBr_(3),forming a heterostructure with a downward band bending at the interface.These features empower the MAPbBr_(3)/ReS_(2) photocatalyst with high capability to promote charge separation and expedite the surface redox reaction.Consequently,optimal BAD and H_(2) production rates of about 1220 μmol h-1 g-1 are realized over a MAPbBr_(3)/ReS_(2) 2%sample,which are approximately 9 times greater than those of blank MAPbBr_(3).This work demonstrates the great potential of constructing an embedded transition metal dichalcogenide@metal halide perovskites heterostructure with downhill interfacial charge transfer for photocatalytic upgrading of biomass-derived alcohols.