New Problems of Boiler Corrosion after Coupling Combustion of Coal and Biomass and Anti-Corrosion Technologies

This study explores the corrosion issues arising from the coupled combustion of coal and biomass and proposes potential solutions.Biomass,as a renewable energy source,offers advantages in energy-saving and carbon reduction.However,the corrosive effects of alkali metal compounds,sulfur(S)and chlorine(Cl)elements in the ash after combustion cannot be underestimated due to the high volatile content of biomass fuels.We investigate the corrosion mechanisms,as well as the transfer of Cl and alkali metal elements during this process.Comparative corrosion analyses are conducted among coal-fired boilers,pure biomass boilers and boilers with coupled combustion.Various biomass types in co-firing are studied to understand different corrosion outcomes.The main factors influencing corrosion include the physicochemical properties of biomass feedstock,furnace temperature and heating surface materials,with the chemical composition and ash content of biomass playing a dominant role.Currently,the methods used for anti-corrosion include water washing pretreatment of biomass feedstock,application of novel alloys and coatings and the development of additives to inhibit fouling,ash deposition and corrosion.Efficient inhibitors are economical and easy to produce.Additionally,biomass can be converted into biomass gasification gas,although challenges related to tar still need to be addressed.

Disordered Translocation is Hastening Local Extinction of the Chinese Giant Salamander

Biodiversity is declining globally by an unprecedented extinction rate.This is especially true for amphibians,accounting for 24.3%of all threatened vertebrates.As the largest extant amphibian species in the world,wild populations of the Chinese giant salamander(Genus Andrias)(CGS)have decreased dramatically because of overexploitation and habitat degradation.Translocation has become an important strategy for restoring threatened wild populations worldwide.However,disordered tra nsloca tion usually has negative effects on the native populations.We provide an overview of CGS translocation and show that disordered translocation can increase local population extinction.Nearly four times the estimated number of wild individuals have been released across China.There a re three types of translocation used for CGS,namely,reinforcement,reintroduction and ecological replacement,the last of which accounts for over one-third of translocations.Our genetic screening revealed that most released individuals were not from local populations,with one to four lineages detected in every release site(n=6).This disordered translocation can potentially reduce the genetic integrity of original populations.Hence,we suggest suspending current CGS translocation activities immediately,until more robust measures can be developed and implemented to improve the current translocation program,especially with respect to lineage identifica tion a nd the identifica tion of appropriate release sites.

An Environment-Friendly High-Performance Aqueous Mg-Na Hybrid-Ion Battery Using an Organic Polymer Anode

Aqueous Mg ion batteries(AMIBs)show great potential in energy storage for their advantages of high capacity,abundant resource,and environmental friendliness.However,the development of AMIBs is limited due to the scarcity of suitable anode materials.In this study,a new polymer anode material(PNTAQ)with flower-like nanosheet structure is synthesized for aqueous Mg-Na hybrid-ion battery(AMNHIB).PNTAQ possess carbonyl functional groups which can be oxidized and reduced reversibly in aqueous solution containing alkaline metal ions.PNTAQ displays a discharge specific capacity of 245 mAh g^(−1)at 50 mA g^(−1)in 1 M MgCl_(2)+0.5 M NaCl electrolyte,which is much higher than that in single 1 M MgCl_(2)or 0.5 M NaCl electrolyte.Even cycling at 1000 mA g^(−1)for 1000 times,the capacity retention can still maintain at 87.2%.A full Mg-Na hybrid-ion cell is assembled by employingβ-MnO_(2)as cathode and PNTAQ as anode material,it exhibits a specific capacity of 91.6 mAh g^(−1)at 100 mA g^(−1).The polymer electrode material well maintains its framework structure during the discharge/charge cycling process of the hybrid-ion battery.

Multifunctional barium titanate ceramics via chemical modification tuning phase structure

Global environmental concerns on the toxicity of lead-based piezoelectrics impel the great mass fervor on investigations of lead-free alternatives.Barium titanate(BaTiO3,BT)ceramics,the first discovered perovskite ferroelectrics,were widely employed to fabricate dielectric capacitors from 1950s.Since a piezoelectric breakthrough was achieved via chemical modification,intensive researches have been performed embracing lead-free BT-based piezoelectrics and their extensional functionalities.In this review,we encompass the stateof-the-art progress on chemical modification tuning phase structure toward advanced electrical properties in BT-based ceramics.Generally,modulated regularity of cations substitution on phase transition is summarized and clarified.Then,we highlight the common methodologies of phase structure(phase boundary,relaxor phase,room-temperature phase transition,etc.)design for optimizing piezoelectricity,electrostrictive strain,electrocaloric,dielectric energy storage or permittivity performances,and cover the noticeable developments and relevant physical mechanisms.Finally,perspectives and challenges on future research issues are featured.This review proposes to exert the significant guidance and service for material design of BT-based and other lead-free perovskite materials with superior functionalities.

N-doped graphene and TiO_2 supported manganese and cerium oxides on low-temperature selective catalytic reduction of NO_x with NH_3

A series of N-doped graphene(NG)and TiO_2 supported MnO_x–CeO_2 catalysts were prepared prepared by a hydrothermal method.The catalysts with different molar ratios of Mn/Ce(6:1,10:1,15:1)were investigated for the low-temperature selective catalytic reduction(SCR)of NO_x with NH_3.The synthesized catalysts were characterized by HRTEM,SEM,XRD,BET,XPS,and NH_3-TPD technologies.The characterization results indicated that manganese and cerium oxide particles dispersed on the surface of the TiO_2–NG support uniformly,and that manganese and cerium oxides existed in different valences on the surface of the TiO_2–NG support.At Mn element loading of 8 wt%,MnO_x–CeO_2(10:1)/TiO_2–1%NG displayed superior activity and improved SO_(2 )resistance.On the basis of the catalyst characterization,excellent catalytic performance and SO_2 tolerance at low temperature were attributed to the high content of manganese with high oxidation valence,extensive oxidation of NO into NO_2 by CeO_2 and strong NO adsorption capacity,and electron transfer of N-doped graphene.

Formation of uniform reduced graphene oxide films on modified PET substrates using drop-casting method

In this work,uniform reduced graphene oxide（RGO） films were formed on poly-（ethylene terephthalate）（PET） substrates using a simple drop-casting method.We investigated four types of substrates：unmodified PET,polydopamine-coated PET.carboxyl-group-modified PET,and alkyl-group-modified PET.Upon water evaporation,the surface of the polydopamine-modified PET substrates can interact with the reduced graphene oxide sheets to form flattened and continuous RGO films,which exhibit a sheet resistance of 21.75 kΩ/sq at 82% transmittance.The result indicates that the properties of the surface groups determined whether uniform and flattened RGO films could be formed on the substrates.Hence,we proposed a simple and effective way to produce transparent and conductive films in which the catechol unit exhibits a great effect on the deposition of uniform RGO films on PET substrates.

Potassium sodium niobate based lead-free ceramic for high-frequency ultrasound transducer applications

The BiAlO_(3)(BA)and(Bi_(0.5)Na_(0.5))ZrO_(3)(BNZ)are selected to form a solid solution with(K_(0.48)Na_(0.52))NbO_(3) via traditional solid state technique to optimize the electrical performance and temperature stability of KNNbased lead-free ceramics,simultaneously.Here we show that doped BA has a great influence on phase structure,morphologies,and electrical properties.The XRD patterns and dielectric constant versus temperature curves reveal that an increase in the BA content results in a transform of phase structures from a coexistence state of rhombohedral,orthorhombic and tetragonal phases to pseudocubic phase.Owing to the construction of R-O-T phase boundary,optimized performances(T_(C)~336℃,d_(33)~306 pC/N,kp=0.48)are obtained in 0.962(K_(0.48)Na_(0.52))NbO_(3)-0.003BiAlO_(3)-0.035(Bi_(0.5)Na_(0.5))ZrO_(3)(KNN-3)ceramics.Based on the sintered KNN-3 ceramic samples,high-frequency ultrasound imaging transducers are designed and fabricated,which exhibits a high center frequency of 24.5 MHz,a broad -6 dB bandwidth of 97% and a high-sensitivity.Finally,the imaging characteristic of the lead-free transducers is demonstrated via ex vivo imaging of biological tissue structure.As environment friendly materials,the excellent electrical and acoustic performance of developed KNN-based ceramics has great potential for practical applications.

Commensal microbiota and host metabolic divergence are associated with the adaptation of Diploderma vela to spatially heterogeneous environments

Heterogeneous environment adaptation is critical to understand the species evolution and response to climate change.However,how narrow-range species adapt to micro-geographic heterogeneity has been overlooked,and there is a lack of insights from metabolism and commensal microbiota.Here,we studied the environmental adaptation for 3 geographic populations(>40 km apart)of Diploderma vela,a lizard endemic to dry-hot valleys of the Hengduan Mountain Region.The climatic boundary caused a cooler,droughtier,and barren environment for northernmost population(RM)than the middle(QZK)and southernmost populations(FS).Correspondingly,significant divergences in liver and muscle metabolism and commensal microbiota were detected between RM and QZK or FS individuals,but not between QZK and FS individuals.Phospholipid composition,coenzyme level(i.e.pyridoxal and NAD^(+)),and cholesterol metabolism(e.g.androgen and estriol synthesis)constituted the major metabolic difference between RM and QZK/FS groups.FS and QZK individuals kept abundant Proteobacteria and antifungal strains,while RM individuals maintained more Firmicutes and Bacteroidota.Strong associations existed between varied host metabolite and gut microbes.How were these interpopulation variations associated to the environment adaptation were discussed.These results provided some novel insights into the environmental adaptation and implicated the consequence of climate change on narrow-range species.

Intraspecific variation in microhabitat selection in reintroduced Chinese giant salamanders

Reintroduction of captive-bred Chinese giant salamanders is a primary approach for restoring wild populations.Despite previous studies have investigated the habitat preferences of reintroduced Chinese giant salamanders,the intraspecific variation in their habitat selection has been neglected.In the present study,30 captive-bred Chinese giant salamanders belonging to 3 groups(i.e.,10 males,10 females,and 10 juveniles)were released into a montane stream to explore whether intraspecific variation in habitat selection occurred in this species using radiotelemetry.Our results indicated that linear home range and daily movement of males were significantly higher than those of females and juveniles.Male sedentariness was significantly lower than that of females and juveniles.No significant differences were detected between females and juveniles in these measures.Importantly,we found that males preferred microhabitats with low water conductivity and deep water depth.Females preferred microhabitats with high water conductivity,low dissolved oxygen and ammonium-nitrogen,and slow current velocity,while juveniles occupied microhabitats with low ammonium-nitrogen.In addition,males and juveniles exhibited higher niche breadth than females.Niche overlap was high between adults and juveniles but low between males and females.Our study revealed the presence of spatial segregation in reintroduced Chinese giant salamanders.Males,females,and juveniles exhibited variation in microhabitat selection.These results provide important information for use when planning strategies for conservation of Chinese giant salamanders.

Strain and illumination triggered regulations of up-conversion luminescence in Er-doped Bi_(0.5)Na_(0.5)TiO_(3)-BaTiO_(3)/Mica flexible multifunctional thin films

External stimuli induced effective regulations of luminescent material are of significant interest in the development of smart optical devices.Here,by simply doping with Er^(3+) in the 0.94Bi_(0.5)Na_(0.5)TiO_(3)-0.06BaTiO_(3)(BNTBT)ferroelectric host,using the bendable mica substrate,and exerting mechanical strain(bending)or light illumination(via photochromic reaction),the all-inorganic,highly-transparent and flexible Er-doped BNTBT/Mica luminescent-ferroelectric thin films were designed and fabricated,displaying strain-induced dramatically elevation of up-conversion photoluminescence(PL)intensity,suppression of PL concentration quenching,outstanding endurance and durability,convenient illuminationmediated PL quenching.And the strain-induced structural changes and local lattice distortions of the thin films were further explored through theoretical calculations and Raman measurement.Our results can supply the guidance of designing other luminescent-ferroelectric materials with controlled PL properties via easy mechanical/photo stimuli for expanding the application of multifunctional wearable memory devices.

Microscopic origin and relevant grain size effect of discontinuous grain growth in BaTiO_(3)-based ferroelectric ceramics

Barium titanate[BaTiO_(3)(BT)]-based ceramics are typical ferroelectric materials.Here,the discontinuous grain growth(DGG)and relevant grain size effect are deeply studied.An obvious DGG phenomenon is observed in a paradigmatic Zr^(4+)-doped BT-based ceramic,with grains growing from∼2.2–6.6 to∼121.8–198.4μm discontinuously near 1320℃.It is found that fine grains can get together and grow into large ones with liquid phase surrounding them above eutectic temperature.Then the grain boundary density(D g)is quantitatively studied and shows a first-order reciprocal relationship with grain size,and the grain size effect is dependent on D g.Fine grains lead to high D g,and then cause fine domains and pseudocubic-like phase structure because of the interrupted long-range ferroelectric orders by grain boundary.High D g also causes the diffusion phase transition and low Curie dielectric peak due to the distribution of phase transition temperature induced by internal stress.Local domain switching experiments reveal that the polarization orientation is more difficult near the grain boundary,implying that the grain boundary inhibition dominates the process of polarization orientation in fine-grain ceramics,which leads to low polarization but a high coercive field.However,large-grain ceramics exhibit easy domain switching and high&similar ferroelectricity.This work reveals that the grain boundary effect dominates the grain size effect in fine-grain ceramics,and expands current knowledge on DGG and grain size effect in polycrystalline materials.

Multiscale Structure Engineering for High-Performance Pb-Free Piezoceramics

CONSPECTUS:The increasing world energy crisis drives humans to harvest the energy in nature as much as possible without heavily damaging the environment.However,most of the energy in nature cannot be used directly.Therefore,pursuing technologies or matter that can directly interconvert different energies has been one of the most cutting-edge fields in science and technology.Such a magic ability exists in true-life piezoelectric materials that generate charge when being given a force and vice versa,rendering them highly promising for energy harvesting and conversion because of the tremendous mechanical energy on the earth,such as tide energy.Thus,piezoelectric materials,represented by the lead zirconate titanate(Pb(Zr,Ti)O_(3),PZT)family,have been largely used in various traditional and burgeoning fields,such as electronic information,biomedical treatment,and wearable flexible electronic devices,and are one of the most important favorites in multidisciplinary fields.However,Pb is highly toxic.Driven by environmental protection and concern for human health,Pb-free piezoceramics are rapidly being developed to hopefully replace Pb-based ones.In particular,the renewal of Restriction of the use of certain Hazardous Substances(e.g.,RoHS 2),issued by the European Union,declared that replacement of PZT“...may be scientif ically and technologically practical to a certain degree...”.Therefore,developing high-performance Pb-free piezoceramics has become more urgent than ever.In this context,some Pb-free piezoceramics,represented by potassium sodium niobate((K,Na)NbO_(3),KNN),barium titanate(BaTiO_(3),BT),bismuth barium titanate((Bi,Na)TiO_(3),BNT),and bismuth ferrite(BiFeO_(3),BFO),stand out because of their unique or similar traits.However,several key challenges,including an inferior overall performance compared to Pb-based counterparts and an unclear structure−property relationship from multiscale viewpoints,have severely hindered the development of Pb-free piezoceramics for a long time.Pb-based piezoceramics possess decent performance due to the strategy of phase boundary engineering,which inspired the researchers to pursue it in Pb-free counterparts.In the last 10 years,our group has been aiming at the new phase boundary(NPB)and new physical phenomenon in Pb-free piezoceramics.This Account presents our recent contributions to the development of Pbfree piezoceramics concerning the good performance and emerging phenomenon.First,we introduce the construction of the NPB in KNN-based piezoceramics by emphasizing the role of some key elements(i.e.,Bi,Sb,Zr,and Hf).Then,we summarize the effects of the NPB on KNN-and BT-based ceramics and the new physical phenomenon in BNT-based ceramics.The NPB boosts the piezoelectric properties and temperature stability of KNN-and BT-based piezoceramics,comparable to some Pb-based piezoceramics.Combining the NPB and the multilayer ceramics substantially enhances the temperature stability of the piezoelectric constant.A new physical phenomenon of the nanoscale bubble domains with polar topologies is for the first time revealed in BNTbased ceramics,showing potential applications for nonconventional and high-density nonvolatile memories.In particular,we emphasize structure engineering from multiscale viewpoints including the local,microscopic,mesoscopic,and macroscopic structure(e.g.,lattice structure,ferroelectric domains,and phase structure).Finally,we provide perspectives on the future developments of Pb-free piezoceramics toward practical applications.

An interpretable machine learning strategy for pursuing high piezoelectric coefficients in (K_(0.5)Na_(0.5))NbO_(3)-based ceramics

Perovskite-type lead-free piezoelectric ceramics allow access to illustrious piezoelectric coefficients(d33)through intricate composition design and experimental modulation.Developing a swift and accurate technology for identifying(K,Na)NbO_(3)(KNN)-based ceramic compositions with high d33 in exceedingly large“compositional”space will establish an innovative research paradigm surpassing the traditional empirical trial-and-error method.Herein,we demonstrate an interpretable machine learning(ML)framework for quick evaluation of KNN-based ceramics with high d33 based on data from published literature.Specifically,a thorough feature construction was carried out from the global and local dimensions to establish tree regression models with d33 as the target property.Subsequently,the feature-property mapping rules of KNN-based piezoelectric ceramics are further optimized through feature screening.To intuitively understand the correlation mechanisms between ML regression targets and features,the sure independence screening and sparsifying operator(SISSO)method was employed to extract the essential descriptors to explain d33.A straightforward descriptor,e^((NMB-MVB))·ST=(IDA)^(2),consisting of only four easily accessible parameters,can accelerate the evaluation of a series of novel KNN-based ceramics with high d33 while exhibiting strong theoretical interpretability.This work not only provides a tool for the rapid discovery of high piezoelectric performance in KNN-based ceramics but also offers a data-driven route for the design of property descriptors in perovskites.

Aggressive Intestinal Symptoms Caused by Metastatic Tumors Originating from Primary Gastric Cancer in Pregnancy:A Case Report

Gastric carcinoma is extremely rare in pregnancy and the prognosis for this malignancy tends to be dismal.We herein describe a case of gastric cancer in pregnancy to alert clinicians to this rare possibility.A 29-year-old woman developed abdominal spastic pain and diarrhea during the 26 weeks of gestation and her condition was confusing and hard to recognize.The patient was initially misdiagnosed as enterogastritis and inflammatory intestinal obstruction and was finally confirmed by exploratory laparotomy with intestinal and peritoneum metastases.Because the disease was not detected early enough and progressed rapidly,the pregnancy was terminated by cesarean section at 30 weeks of gestation,and then followed by systemic chemotherapy,but eventually succumbed to the lethal pneumonia.Therefore,it is of great significance to alert clinicians to note this rare possibility and to consider the differential diagnosis of this disease in pregnant women with a long course of gastrointestinal symptoms that cannot be explained by pregnancy alone,and cancer should be suspected and tested with sophisticated diagnostic procedures.

Frequency-dependent ferroelectric and electrocaloric properties in barium titanate-based ceramics based on Maxwell relations

In this work,the frequency dependence of ferroelectric and electrocaloric properties in barium titanate-based ceramics was studied based on Maxwell relations.It is found that the maximum and remnant polarization will decrease while the coercive field increases a lot with rising frequency from 0.1 to 10 Hz,indicating that polarization rotation and domain switching become difficult at high frequencies.The electrocaloric properties show the different frequency dependence at different phase structures.Isothermal entropy change(ΔS)and adiabatic temperature change(ΔT)are similar around/above Curie temperature(TCT,showing tiny frequency dependence.However,ΔS andΔT display the obvious frequency dependence below T_(C),especially in the orthorhombic–tetragonal phase-transition region with a stable ferroelectric phase,and this frequency dependence becomes more obvious under a low-electric field.It is also found that increasing the frequency can weaken the electric field dependence of electrocaloric strength.This work gives a general profile of frequency dependence for electrocaloric properties in ferroelectric ceramics.