Enhancing electromagnetic wave absorption with core‐shell structured SiO_(2)@MXene@MoS_(2) nanospheres

Material composition and structural design are important factors influencing the electromagnetic wave(EMW)absorption performance of materials.To alleviate the impedance mismatch attributed to the high dielectric constant of Ti_(3)C_(2)T_(x)MXene,we have successfully synthesized core‐shell structured SiO_(2)@MXene@MoS_(2)nanospheres.This architecture,comprising SiO_(2) as the core,MXene as the intermediate layer,and MoS_(2) as the outer shell,is achieved through an electrostatic self‐assembly method combined with a hydrothermal process.This complex core‐shell structure not only provides a variety of loss mechanisms that effectively dissipate electromagnetic energy but also prevents self‐aggregation of MXene and MoS_(2) nanosheets.Notably,the synergistic combination of SiO_(2) and MoS_(2) with highly conductive MXene enables the suitable dielectric constant of the composites,ensuring optimal impedance matching.Therefore,the core‐shell structured SiO_(2)@MXene@MoS_(2) nanospheres exhibit excellent EMW absorption performance,featuring a remarkable minimum reflection loss(RL_(min))of−52.11 dB(2.4 mm).It is noteworthy that these nanospheres achieve an ultra‐wide effective absorption bandwidth(EAB)of 6.72 GHz.This work provides a novel approach for designing and synthesizing high‐performance EMW absorbers characterized by“wide bandwidth and strong reflection loss.”

Polo-like kinase 1 as a biomarker predicts the prognosis and immunotherapy of breast invasive carcinoma patients

Invasive breast carcinoma(BRCA)is associated with poor prognosis and high risk of mortality.Therefore,it is critical to identify novel biomarkers for the prognostic assessment of BRCA.Methods:The expression data of polo-like kinase 1(PLK1)in BRCA and the corresponding clinical information were extracted from TCGA and GEO databases.PLK1 expression was validated in diverse breast cancer cell lines by quantitative real-time polymerase chain reaction(qRT-PCR)and western blotting.Single sample gene set enrichment analysis(ssGSEA)was performed to evaluate immune infiltration in the BRCA microenvironment,and the random forest(RF)and support vector machine(SVM)algorithms were used to screen for the hub infiltrating cells and calculate the immunophenoscore(IPS).The RF algorithm and COX regression model were applied to calculate survival risk scores based on the PLK1 expression and immune cell infiltration.Finally,a prognostic nomogram was constructed with the risk score and pathological stage,and its clinical potential was evaluated by plotting calibration charts and DCA curves.The application of the nomogram was further validated in an immunotherapy cohort.Results:PLK1 expression was significantly higher in the tumor samples in TCGA-BRCA cohort.Furthermore,PLK1 expression level,age and stage were identified as independent prognostic factors of BRCA.While the IPS was unaffected by PLK1 expression,the TMB and MATH scores were higher in the PLK1-high group,and the TIDE scores were higher for the PLK1-low patients.We also identified 6 immune cell types with high infiltration,along with 11 immune cell types with low infiltration in the PLK1-high tumors.A risk score was devised using PLK1 expression and hub immune cells,which predicted the prognosis of BRCA patients.In addition,a nomogram was constructed based on the risk score and pathological staging,and showed good predictive performance.Conclusions:PLK1 expression and immune cell infiltration can predict post-immunotherapy prognosis of BRCA patients.

Effects of Grape Seeds and Tea Polyphenols on Serum Enzymatic Indices of Finless Eels ( Monopterus albus )

[Objectives]This study was conducted to investigate the possibility of adding grape seeds and tea polyphenols to improve the health of finless eels(Monopterus albus).[Methods]Twelve cages were selected in the same water body and divided into 4 groups,each with 3 parallel groups.The control group was fed with common finless eel feed,and the experimental groups were fed with feed supplemented with grape seeds,tea polyphenols,and grape seed-tea polyphenol compound(with a ratio of grape seeds to tea polyphenols at 1∶1),respectively.The feeding amount of each additive was 1%.The experiment was carried out by feeding medicated feed for 3 d and ordinary feed for 3 d,that is,alternately feeding medicated feed and ordinary feed.The experiment lasted for 18 d.[Results]Six serum enzymatic indices were detected after the breeding.The results showed that compared with the control group,the three groups of samples had a certain protective effect on the liver in terms of liver function indices.In terms of immunity evaluation,the tea polyphenol group and the grape seed-tea polyphenol complex group could increase the immunity of eels to varying degrees.In terms of antioxidant capacity,all three groups of samples could increase the body's antioxidant capacity.The results of this study showed that adding tea polyphenols and grape seeds to the feed simultaneously could effectively protect the liver of fish,and simultaneously enhance their antioxidant and non-specific immune functions.[Conclusions]This study provides a reference for the application of the two Chinese herbal medicines,grape seeds and tea polyphenols,in finless eel farming.

Serum and Blister Fluid Pharmacokinetics of Amikacin in Severe Burn Patients

Objective: To characterize amikacin pharmacokinetics in serum and in blister fluid of severe burn patients to guide optimal treatment timing. Methods: Patients (N = 32) were divided into four groups based on amikacin administration timing and groups received drug minutes to hours after injury. In Groups A, B, C, and D, amikacin (400 mg, IV) was administered 3 - 4, 10, 20 and 30 h post burn injury, respectively (N = 8 for all groups). Next blister fluid and venous blood samples from 9 patients were obtained at 0, 0.25, 0.5, 1, 2, 3, 4, 5, 6, and 7 h after drug infusion. Amikacin concentrations were measured with a fluorescent polarization immunoassay and pharmacokinetics was deduced using DAS3.2.5. Statistical analyses performed with SPSS13.0. Results: Compared with normal values, t1/2z of amikacin from burn patients was shortened in serum but amikacin half-lives in blister fluid was significantly greater than serum half-life values (p < 0.05). Groups A and B had greater pharmacokinetic values at each time point, and Group D did not achieve antibacterial concentrations of amikacin. Conclusion: Early amikacin administration in severe burn patients offers greater concentrations of drug in serum and blister fluids.

Thruster direction controlling of assembled spacecraft based on gimbal suspension

The attitude control system design and its control effect are affected considerably by the mass-property parameters of the spacecraft. In the mission of on-orbit servicing, as fuel is expended, or the payloads are added or removed, the center of mass will be changed in certain axe; consequently, some thrusters＇ directions are deviated from the center of mass（CM） in certain plane. The CM of assembled spacecraft estimation and thruster direction control are studied. Firstly, the attitude dynamics of the assembled spacecraft is established based on the Newton-Euler method. Secondly, the estimation can be identified by the least recursive squares algorithm. Then, a scheme to control the thrusters＇ directions is proposed. By using the gimbal installed at the end of the boom, the angle of the thruster is controlled by driving the gimbal; therefore, thrusters can be directed to the CM again. Finally, numerical simulations are used to verify this scheme. Results of the numerical simulations clearly show that this control scheme is rational and feasible.

Novel hierarchical structure of MoS_(2)/TiO_(2)/Ti_(3)C_(2)T_(x) composites for dramatically enhanced electromagnetic absorbing properties

In order to prevent the microwave leakage and mutual interference,more and more microwave absorbing devices are added into the design of electronic products to ensure its routine operation.In this work,we have successfully prepared MoS_(2)/TiO_(2)/Ti_(3)C_(2)T_(x) hierarchical composites by one-pot hydrothermal method and focused on the relationship between structures and electromagnetic absorbing properties.Supported by comprehensive characterizations,M0S_(2) nanosheets were proved to be anchored on the surface and interlayer of Ti_(3)C_(2)T_(x) through a hydrothermal process.Additionally,TiO_(2) nanoparticles were obtained in situ.Due to these hierarchical structures,the MoS_(2)/TiO_(2)/Ti_(3)C_(2)T_(x) composites showed greatly enhanced microwave absorbing performance.The MoS_(2)/TiO_(2)/Ti_(3)C_(2)T_(x) composites exhibit a maximum reflection loss value of -33.5 dB at 10.24 GHz and the effective absorption bandwidth covers 3.1GHz(13.9-17 GHz)at the thickness of 1.0 mm,implying the features of wide frequency and light weight.This work in the hierarchical structure of MoS_(2)/TiO_(2)/Ti_(3)C_(2)T_(x) composites opens a promising door to the exploration of constructing extraordinary electromagnetic wave absorbents.

(Ca,Sr,Ba)ZrO_(3):A promising entropy-stabilized ceramic for titanium alloys smelting

A novel entropy-stabilized(ES)(Ca,Sr,Ba)ZrO_(3) ceramic has been designed and synthesized by pressureless sintering of CaZr03,SrZr03 and BaZr03 powders mixtures at 1450℃,1500℃and 1550℃for 3 h.X-ray diffraction,scanning electron microscopy and transmission electron microscopy analyses collectively indicate that a single solid solution is formed with a homogeneous distribution of metal elements after sintering at 1550℃.The relative density and hardness of the ES(Ca,Sr,Ba)ZrO_(3) ceramic sintered at 1550℃are 97.79%and 10.840.33 GPa,re s pectively.This ES(Ca,Sr,Ba)ZrO_(3) exhibits lower thermal conductivity from 373 K to 1073 K than their constituting zirconates,CaZrO_(3),SrZrO_(3) and BaZrO_(3).Most importantly,the ES(Ca,Sr,Ba)ZrO_(3) ceramic possesses good corrosion resistance to TiNi alloy melt and no distinct reaction layer exists between TiNi alloy and ES(Ca,Sr,Ba)ZrO_(3) ceramic in the contact region.The combination of these properties indicates that ES(Ca,Sr,Ba)ZrO_(3) ceramic is promising for use as a novel crucible material for the melting of titanium alloys.

Polymer-derived SiBCN ceramic pressure sensor with excellent sensing performance

Pressure measurement with excellent stability and long time durability is highly desired,especially at high temperature and harsh environments.A polymer-derived silicoboron carbonitride(SiBCN)ceramic pressure sensor with excellent stability,accuracy,and repeatability is designed based on the giant piezoresistivity of SiBCN ceramics.The SiBCN ceramic sensor was packaged in a stainless steel case and tested using half Wheatstone bridge with the uniaxial pressure up to 10 MPa.The SiBCN ceramic showed a remarkable piezoresistive effect with the gauge factor(K)as high as 5500.The output voltage of packed SiBCN ceramic sensor changes monotonically and smoothly versus external pressure.The as received SiBCN pressure sensor possesses features of short response time,excellent repeatability,stability,sensitivity,and accuracy.Taking the excellent high temperature thermo-mechanical properties of polymer-derived SiBCN ceramics(e.g.,high temperature stability,oxidation/corrosion resistance)into account,SiBCN ceramic sensor has significant potential for pressure measurement at high temperature and harsh environments.

Microwave induced in-situ formation of SiC nano wires on SiCNO ceramic aerogels with excellent electromagnetic wave absorption performance

Electromagnetic absorption(EMA)materials with light weight and harsh environmental robustness are highly desired and crucially important in the stealth of high-speed vehicles.However,meeting these two requirements is always a great challenge,which excluded the most attractive lightweight candidates,such as carbon-based materials.In this study,SiC_(nw)-reinfbrced SiCNO(SiC_(nw)/SiCNO)composite aerogels were fabricated through the in-situ growth of SiC_(nw) in polymer-derived SiCNO ceramic aerogels by using catalyst-assisted microwave heating at ultra-low temperature and in short time.The phase composition,microstructure,and EMA property of the SiC_(nw)/SiCNO composite aerogels were systematically investigated.The results indicated that the morphology and phase composition of SiC_(nw)/SiCNO composite aerogels can be regulated easily by varying the microwave treatment temperature.The composite aerogels show excellent EMA property with minimum reflection loss of -23.9 dB@13.8 GHz,-26.5 dB@10.9 GHz,and -20.4 dB@14.5 GHz and the corresponding effective bandwidth of 5.2 GHz,3.2 GHz,and 4.8 GHz at 2.0 mm thickness for microwave treatment at 600℃,800℃,and 1000℃,respectively,which is much better than that of SiCN ceramic aerogels.The superior EMA performance is mainly attributed to the improved impedance matching,multireflection,multi-interfacial polarization,and micro current caused by migration of hopping electrons.

Oscillatory pressure-assisted sinter forging for preparation of high-performance SiC whisker reinforced Al_(2)O_(3) composites

In this work,a novel process,oscillatory pressure-assisted sinter forging(OPSF),for the preparation of high-performance ceramic composites was reported.Compared with the samples made by conventional sinter forging(SF)and hot oscillatory pressing(HOP),the SiC whisker reinforced Al_(2)O_(3) composites(SiCw–Al_(2)O_(3))prepared by OPSF at the same temperature exhibited a higher density and significantly improved the mechanical properties.The improvements in densification and performance are attributed to simultaneous enhanced shear deformation at both macro-and micro-scales,resulting from the combination of die-free configuration and oscillatory pressure of OPSF.And the strength of grain boundary is greatly increased when the temperature reaches 1600℃ of OPSF,due to that the grain-boundary sliding became pronounced at higher temperatures.The current results shed light on a powerful technique for preparing ceramic composites,which is likely applicable to other systems.

Sintering behavior of alumina whisker reinforced zirconia ceramics in hot oscillatory pressing

Alumina whisker reinforced zirconia ceramic composite was prepared by both hot oscillatory pressing(HOP)and conventional hot pressing(HP).The results show that compared with HP,HOP can significantly increase the final density and densification rate of the material.Analysis of densification kinetics reveals that the predominant densification mechanism transits from grain boundary sliding in the beginning to the diffusion in the later stage.The main effect of the oscillating pressure is to increase the densification rate in the process of grain boundary sliding.The current study suggests that HOP is a promising technique for densifying whisker reinforced ceramics.

Can floor-area-ratio incentive promote low impact development in a highly urbanized area？ A case study in Changzhou City, China

As an environmental friendly measure Jbr surface runoff reduction, low impact development （LID） has been applied successfully in urban areas. However, due to high price of land and additional expense for LID construction in highly urbanized areas, the developers of real estate would not like to proceed LID exploitation. Floor area ratio （FAR） refers to ＂the ratio ofa building＇s total floor area to the size of the piece of land upon which it is built.＇＂ Increasing FAR indicates that the developers can construct higher buildings and earn more money. By means of awarding FAR, the developers may be willing to practice LID construction. In this study, a new residential district is selected as a case study to analyze the trade- offbetween the runoffreduction goal achieving by LID practices and the incentive of awarding FAR to promote LID construction. The System for Urban Stormwater Treatment and Analysis IntegratioN （SUSTAIN） model is applied to simulate the runoff reduction under various LID designs and then derive the Pareto-optimal solutions to achieve urban runoff reduction goals based on cost efficiency. The results indicates that the maximum surface runoff reduction is 20.5%. Under the extremity scenarios, the government has options to award FAR of 0.028, 0.038 and 0.047 and the net benefits developers gain are 0 CNY, one million CNY and two million CNY, respectively. The results provide a LID construction guideline related to awarding FAR, which supports incentive policy making for promoting LID practices in the highly urbanized areas.