Internal Polarization Field Induced Hydroxyl Spillover Effect for Industrial Water Splitting Electrolyzers

The formation of multiple oxygen intermediates supporting efficient oxygen evolution reaction(OER)are affinitive with hydroxyl adsorption.However,ability of the catalyst to capture hydroxyl and maintain the continuous supply at active sits remains a tremendous challenge.Herein,an affordable Ni2P/FeP2 heterostructure is presented to form the internal polarization field(IPF),arising hydroxyl spillover(HOSo)during OER.Facilitated by IPF,the oriented HOSo from FeP2 to Ni2P can activate the Ni site with a new hydroxyl transmission channel and build the optimized reaction path of oxygen intermediates for lower adsorption energy,boosting the OER activity(242 mV vs.RHE at 100 mA cm-2)for least 100 h.More interestingly,for the anion exchange membrane water electrolyzer(AEMWE)with low concentration electrolyte,the advantage of HOSo effect is significantly amplified,delivering 1 A cm^(-2)at a low cell voltage of 1.88 V with excellent stability for over 50 h.

Internal electric field modulation by copper vacancy concentration of cuprous sulfide nanosheets for enhanced selective CO_(2) photoreduction

Although the internal electric field(IEF)of photocatalysts is acknowledged as a potent driving force for photocharge separation,modulating the IEF intensity to achieve enhanced photocatalytic performances remains a challenge.Herein,cuprous sulfide nanosheets with different Cu vacancy concentration were employed to study IEF modulation and corresponding direct charge transfer.Among the samples,Cu_(1.8)S nanosheets possessed intensified IEF intensity compared with those of Cu_(2)S and Cu_(1.95)S nanosheets,suggesting that an enhanced IEF intensity could be achieved by introducing more Cu vacancies.This intensified IEF of Cu_(1.8)S nanosheets induced numerous photogenerated electrons to migrate to its surface,and the dissociative electrons were then captured by Cu vacancies,resulting in efficient charge separation spatially.In addition,the Cu vacancies on Cu_(1.8)S nanosheets accumulated electrons as active sites to lower the energy barrier of rate-determining step of CO_(2)photoreduction,leading to the selective conversion of CO_(2)to CO.Herein,the manipulation of IEF intensity through Cu vacancy concentration regulation of cuprous sulfide photocatalysts for efficient charge separation has been discussed,providing a scientific strategy to rationally improve photocata lytic performances for solar energy conversion.

Internal field study of 21700 battery based on long-life embedded wireless temperature sensor

The safety of lithium-ion batteries is an essential concern where instant and accurate temperature sensing is critical.It is generally desired to put sensors inside batteries for instant sensing.However,the transmission of internal measurement outside batteries without interfering their normal state is a non-trivial task due to the harsh electrochemical environment,the particular packaging structures and the intrinsic electromagnetic shielding problems of batteries.In this work,a novel in-situ temperature sensing framework is proposed by incorporating temperature sensors with a novel signal transmission solution.The signal transmission solution uses a self-designed integrated-circuit which modulates the internal measurements outside battery via its positive pole without package breaking.Extensive experimental results validate the noninterference properties of the proposed framework.Our proposed in-situ temperature measurement by the self-designed signal modulation solution has a promising potential for in-situ battery health monitoring and thus promoting the development of smart batteries.

Geometrical shape of in-plane inclusion characterized by polynomial internal stress field under uniform eigenstrains

The internal stress field of an inhomogeneous or homogeneous inclusion in an infinite elastic plane under uniform stress-free eigenstrains is studied. The study is restricted to the inclusion shapes defined by the polynomial mapping functions mapping the exterior of the inclusion onto the exterior of a unit circle. The inclusion shapes, giving a polynomial internal stress field, are determined for three types of inclusions, i.e., an inhomogeneous inclusion with an elastic modulus different from the surrounding matrix, an inhomogeneous inclusion with the same shear modulus but a different Poisson＇s ratio from the surrounding matrix, and a homogeneous inclusion with the same elastic modulus as the surrounding matrix. Examples are presented, and several specific conclusions are achieved for the relation between the degree of the polynomial internal stress field and the degree of the mapping function defining the inclusion shape.

SPONTANEOUS POLARIZATION AND THE DISTRIBUTION OF INTERNAL STRESS AND ELECTRIC FIELDS AROUND A TRIPLE POINT

In this article, distributions of internal stress and internal electric fields around a triple point of ferroelectric polycrystals generated by the spontaneous deformation and spontaneous polarization were investigated. It was found that when all three grains consist of a single domain, the internal stresses and the internal electric fields do not vanish. Though it may be determined according to the principle of energy, the spontaneous configuration will not be unique without involving other conditions due to the symmetry of the crystal structure.

Energy Spectrum of Linear Internal Wave Field in the Vicinity of Continental Slope

The purpose of the research was to investigate two-dimensional modeling of efficiency of mixing, resulting from the reflection of a linear internal wave field (IWF) off a continental slope. Efficiency of deep ocean mixing was associated with the energy balance of the radiating IWF into an interior of the ocean in the vicinity of a sloping bottom topography. Since waves are generated not only at the fundamental frequency but also at all of its harmonics ωn = nω less than buoyancy frequency N and greater than Coriolis frequency f, our analysis includes, in general, an infinite number of discrete internal wave modes n satisfying the dispersion relationship for internal waves. However, since we are interested only in the radiating part of the field, the mode numbers are limited. Due to multiple singularities of order two caused by resonance in the vicinity of critical slope, the energy is visualized in Lδ -norm with δ > 2. Research results include the visualization of the effects of the continental slope and the Earth’s rotation on resulting energy in the vicinity of the slope.

Revisiting N,S co-doped carbon materials with boosted electrochemical performance in sodium-ion capacitors:The manipulation of internal electric field

Heteroatom doping has emerged as a prevailing strategy to enhance the storage of sodium ions in carbon materials.However,the underlying mechanism governing the performance enhancement remains undisclosed.Herein,we fabricated N/S co-doped carbon beaded fibers(S-N-CBFs),which exhibited glorious rate performance and durableness in Na+storage,showcasing no obvious capacity decay even after 3500 cycles.Furthermore,when used as anodes in sodium-ion capacitors,the S-N-CBFs delivered exceptional results,boasting a high energy density of 225 Wh·kg^(-1),superior power output of 22500 W·kg^(-1),and outstanding cycling stability with a capacity attenuation of merely 0.014%per cycle after 4000 cycles at 2 A·g^(-1).Mechanistic investigations revealed that the incorporation of both pyridinic N and pyrrolic N into the carbon matrix of S-N-CBFs induced internal electric fields(IEFs),with the former IEF being stronger than the latter,in conjunction with the doped S atom.Density functional theory calculations further unveiled that the intensity of the IEF directly influenced the adsorption of Na+,thereby resulting in the exceptional performances of S-N-CBFs as sodium-ion storage materials.This work uncovers the pivotal role of IEF in regulating the electronic structure of carbon materials and enhancing their Na^(+)storage capabilities,providing valuable insights for the development of more advanced electrode materials.

Magnetic Field Design by Using Image Effect from Iron Shield

Permanent magnet rings are presented, which exploit the image effect in the surrounding circular iron shields. The theory is given for a general permanent ring when the magnetization orientation at each coordinate angle ψ changes by =(n+1)ψ, where n is a positive or negative integer. For the uniformly magnetized case n=-1, the permanent ring produces no field in its bore, and the field is that of a dipole outside. When the ring is surrounded by a soft iron shield, its field becomes uniform in the bore, and zero outside the ring. The field can be varied continuously by moving the iron shield along the magnet axis. A small variable field device was constructed by using NdFeB permanent rings, which produced a field flux density of 0-0.5 T in the central region.

INTERNAL FLOW IN CROSS-FLOW FAN FOR AIR CONDITIONER

A numerical analytic process is suggested combining direct boundary element methodwith discrete vortex method and internal flow in cross-flow fan calculated. The process considersnot only function of impeller, but also effect of volute casing. Internal flow field of cross-flow fan ispractically measured, and results compared with that from calculation. It shows that the process isexpected to be used in predicting performances of fluid machinery.

Regulating crystallinity in linear conjugated polymer to boost the internal electric field for remarkable visible-light-driven disinfection

Conjugated linear polymers are promising metal-free photocatalysts for visible-light-driven photocatalytic water disinfection,but it was still bottlenecked by the insufficient photogenerated charge separation and transport(CST)process.Herein,we obtained the highly crystalline imine-linked conjugated linear poly-mer(ODA-BPAH)with a greatly enhanced CST process.The highly crystalline ODA-BPAH exhibited excel-lent broad-spectrum water disinfection efficiency up to 99.99999%in 1 h,which is among the reported highest of state-of-the-art photocatalysts.The crystallinity of ODA-BPAH was regulated by simply turn-ing the solvent and the experiment results revealed that the ODA-BPAH with high crystallinity exhibited higher internal electric field strength and photocatalytic performance than that with low crystallinity,which indicates that higher crystallinity in linear conjugated polymers contributes to superior CST ef-ficiency as well as the generation of reactive oxygen species.This work highlights the impact of poly-mer crystallinity on the internal electric field and proves that linear poly-imine could be a new type of promising metal-free photocatalyst for water treatment.

Performance Prediction of an Optimized Centrifugal Pump with High Efficiency

The main structural parameters of the IR100-80-100A type chemical centrifugal pump have been optimized by means of an orthogonal test approach.The centrifugal pump has been modeled using the CFturbo software,and 16 sets of orthogonal-test schemes have been defined on the basis of 4 parameters,namely,the blade number,blade outlet angle,impeller outlet diameter,and impeller outlet width.Such analysis has been used to determine the influence of each index parameter on the pump working efficiency and identify a set of optimal combinations of such parameters.The internalflowfield in the centrifugal pump has been simulated by using the PumLinx software.These numerical results have shown that,compared with the prototype pump,the outlet pressure and shaft power of the optimized pump can be significantly reduced,and the pump working efficiency can be improved by 5.59%.In the present study,some arguments are also provided to demonstrate that,with respect to other optimization methods,the orthogonal test approach is more convenient,and requires less test times.

Superstable potassium metal batteries with a controllable internal electric field

Stable potassium metal batteries(PMBs)are promising candidates for electrical energy storage due to their ability to reversibly store electrical energy at a low cost.However,dendritic growth and large volume changes hinder their practical application.Here,referring to the morphology and structure of a virus,a bionic virus-like-carbon microsphere(BVC)was designed as the anode host for a PMB.A BVC with a three-dimensional structure can not only control the electric field,which can suppress dendrite formation,but can also provide a larger space to accommodate the volume change during the cycle progress.The designed potassium(K)metal anode exhibits excellent cycle life and stability(during 1800 h of repeated plating/stripping of K at a current density of 0.1 mA cm−2,K-BVC can realize a very stable K metal anode with low voltage hysteresis).Stable cyclability and improved rate capability can be realized in a full cell using Prussian blue over 400 cycles.This research provides a new idea for the development of stable K metal anodes and may pave the way for the practical application of next-generation metal batteries.

Strong interface interaction and internal electric field promote electron transfer of Bi_(2)O_(2)S/NiFe_(2)O_(4) heterojunction for photocatalytic antibiotic degradation

Heterojunction photocatalysts have shown considerable activities for organic pollutants degradation.However,the faint connection interface and inferior charge shift efficiency critically block the property of heterojunction photocatalysis.Herein,Bi_(2)O_(2)S/NiFe_(2)O_(4) nanosheets heterojunction with ultrastrong inter-face interaction and high internal electric field are designed by an in-situ growth method.Tentative and theoretical consequences prove that the interfacial interaction and internal electric field not only act as the electron flow bridge but also decrease the electrons shift energy obstacle,thus speeding up electrons transfer and achieving effective spatial electron-hole separation.Therefore,a large amount of·O_(2)^(-)and holes as active species were generated.Remarkably,Bi_(2)O_(2) S/NiFe_(2)O_(4) establishes a considerably boosted photocatalytic performance for tetracycline degradation(0.032 min^(-1)),which is about 14.2-fold and 7.8-fold of the pristine BOS and NFO,respectively.This work provides a promising motivation for modulating charge transfer by interface control and internal electric field to boost photocatalytic performance.

Superposition of dual electric fields in covalent organic frameworks for efficient photocatalytic hydrogen evolution

Covalent organic frameworks(COFs)are promising materials for converting solar energy into green hydrogen.However,limited charge separation and transport in COFs impede their application in the photocatalytic hydrogen evolution reaction(HER).In this study,the intrinsically tunable inter-nal bond electric field(IBEF)at the imine bonds of COFs was manipulated to cooperate with the internal molecular electric field(IMEF)induced by the donor-acceptor(D-A)structure for an effi-cient HER.The aligned orientation of IBEF and IMEF resulted in a remarkable H_(2)evolution rate of 57.3 mmol·g^(-1)·h^(-1)on TNCA,which was approximately 520 times higher than that of TCNA(0.11 mmol·g^(-1)·h^(-1))with the opposing electric field orientation.The superposition of the dual electric fields enables the IBEF to function as an accelerating field for electron transfer,kinetically facilitat-ing the migration of photogenerated electrons from D to A.Furthermore,theoretical calculations indicate that the inhomogeneous charge distribution at the C and N atoms in TNCA not only pro-vides a strong driving force for carrier transfer but also effectively hinders the return of free elec-trons to the valence band,improving the utilization of photoelectrons.This strategy of fabricating dual electric fields in COFs offers a novel approach to designing photocatalysts for clean energy synthesis.

Correlation Research between Turbulent Pressure Pulsation and Internal Sound Field Characteristics of Centrifugal Pump

In order to study the correlation between the internal flow noise of the centrifugal pump and the turbulent pressure pulsation,a single-stage single-suction centrifugal pump was used as the research object by the combination of numerical calculation and experiment.Based on the RNG k-?model and the N-S equation,the model pump was simulated numerically by CFD.A dipole sound source was extracted by the turbulent pulse action of the volute wall surface according to the FW-H equation.The acoustic field of the model pump was solved on the basis of the boundary element method,and the sound pressure distribution of the internal flow field under the action of the dipole sound source of the volute wall and the frequency response of the inlet and outlet fields were obtained.The results show that the distribution of hydrodynamic noise inside the centrifugal pump is related to the pressure pulsation,presenting obvious dipole distribution and disturbance at the tongue.The sound pressure value of the field is mainly concentrated in the blade passing frequency and double frequency,in which the blade passing frequency is the strongest,and the sound pressure value decreases obviously under other double frequency.The main frequency of hydrodynamic noise is the blade passing frequency.

The first-principles study of ferroelectric behaviours of PbTiO3/SrTiO3 and BaTiOn/SrTiO3 superlattices

We have performed the first-principles calculation to investigate the origins of ferroelectricities and different po- larization behaviours of superlattices BaTiO3/SrTiO3 and PbTiO3/SrTiO3. The density of state （DOS） and electronic charge profiles show that there are strong hybridizations between atoms Ti and O and between atoms Pb and O which play very important roles in producing the ferroelectricities of superlattices BaTiO3/SrTiO3 and PbTiO3/SrTiO3. Ow- ing to the decline of internal electric field in SrTiO3 （ST） layer, the tetragonality and polarizations of superlattices decrease with increasing the fraction of SrTiO3 in the superlattices. We find that the polarization of PbTiO3/SrTiO3 is largerthan that of BaTiO3/SrTiO3 at the same ratio of components, because the polarization mismatch between PbTiO3 and SrTiO3 is larger than that between BaTiO3 and SrTiO3. The polarization and tetragonality are en- hanced with respect to those of bulk tetragonal BaTiO3 in the superlattices BaTiO3/SrTiO3, while the polarization and tetragonality are reduced with respect to those of bulk tetragonal PbTiO3 in superlattices PbTiO3/SrTiO3.

Significantly enhanced charge transfer efficiency and surface reaction on NiP_(2)/g-C_(3)N_(4) heterojunction for photocatalytic hydrogen evolution

In this work,a novel NiP_(2)/g-C_(3)N_(4)heterojunction via homogeneous precipitation method assisted by thermal phosphorization reaction was designed and constructed,and the optimized sample showed the excellent photocatalytic H_(2)evolution activity under visible-light irradiation,which was nearly 112 times higher than that of pristine g-C_(3)N_(4)sample.Experimental characterizations and DFT calculations demonstrated that the NiP_(2)nanoparticles covered on the g-C_(3)N_(4)surface can form a built-in electric field at the interface to accelerate the transfer of photoexcited electrons from g-C_(3)N_(4)to NiP_(2),crucial for hindering the recombination of electron-hole pairs.Moreover,the energy barrier of hydrogen evolution reaction can also vastly reduce when combined NiP_(2)and g-C_(3)N_(4)to construct NiP_(2)/g-C_(3)N_(4)heterojunction.This work represents a method through combing experimental and theoretical tools to thoroughly investigate the mechanism of photocatalytic process.

The fluctuation of acoustic field due to internal waveson the thermocline in typical shallow water

In this paper, the results of experiments concerning the fluctuations of internal waves on the thermocline and the fluctuations of acoustic amplitudes at different ranges in typical shallow water are presented. Recorded time is 48.96 h. Thickness of the thermocline is about 2 m-4 m. The deviation of temperature recorded at a fixed depth is 10℃-15℃. The vertical displacement of isotherm curves is about 5 m-6 m, which is mainly dominated by the lowest model. The measured spectrums of vertical displacement have obvious spectral packet within the range of 0.05 cpm (20 min) and 0. 143 cpm (7 min) besides the diurnal and semidiurnal tide frequency bands. Spectrum attenuation coefficients are between -1.5 and -1.7. Numerical calculation shows that phase velocity and group velocity of internal waves are equal to 0.329 m/s at lower frequencies. And with the increasing of frequency, the group velocity differs from phase velocity at about 0.03 cpm (33.33 min) and drops more quickly. The measured fluctuation of acoustic amplitude is about 8 dB-10 dB. With the increasing of range, the fluctuation trends to be faster and acoustic signals are declining. Spectrum attenuation coefficients are between -1.45 and -2.0. At last, PE method is used to simulate the acoustic amplitude fluctuation, in which internal waves are the important element.

碳量子点/四(4-羧基苯基)卟啉/BiOBr S型异质结用于高效光催化降解抗生素

太阳能光催化处理制药废水是缓解环境问题和能源危机的一种很有前途的方法.然而,提高其处理效率面临众多挑战,如光吸收效率低、光生载流子快速复合和光氧化还原电位低等.本文通过在BiOBr(BOB)微球上沉积碳量子点(CDs)和四(4-羧基苯基)卟啉(TCPP),巧妙地构建了TCPP/CDs/BOB有机/无机三元S型异质结,用于在可见光下有效降解水体中的盐酸四环素(TC).研究发现,由于两者之间的费米能级差异,在形成异质结时触发了电子从TCPP传递到BOB,从而在界面处构建内部电场(IEF).这极大推动了光诱导载流子的有效分离.此外,CDs作为电子收集器进一步提高了S型异质结的载流子分离能力,因此保留了在CDs中聚集更强还原能力的光电子和在BOB价带中更强氧化能力的空穴来参与光催化反应.在这些催化剂中,TCPP/CDs/BOB-2异质结催化剂在40 min内对TC的降解能力高达83.6%.TCPP/CDs/BOB-2的反应速率常数(k)分别约为BOB、CDs/BOB和TCPP/BOB的2.3、1.8和2.0倍.这项工作为探索用于水净化的有机/无机三元S型光催化剂提供了新的视角.

Z型电荷分离介导的0D/2D AgVO_(3)/TiO_(2)异质结用于增强光催化CO_(2)还原

合理利用Z型电荷调节机制是提高光催化CO_(2)还原效率的有效策略.在本工作中,通过将AgVO_(3)量子点(QDs)原位锚定在TiO_(2)纳米片(NSs)上,从而构建了0D/2D AgVO_(3)/TiO_(2)直接Z型异质结光催化剂.TiO_(2)NSs抑制了AgVO_(3)量子点自身的团聚,从而优化了体系的形貌结构.AgVO_(3)QDs增强了复合材料的光吸收能力,从而提高了对太阳光的利用效率.同时,两种单体之间匹配的能带结构和合适的内部界面电场(即(-)AgVO_(3)/(+)TiO_(2))促进了直接Z型异质结的构建,从而显著促进了光生电子-空穴对的分离,并保持了体系中最高的氧化还原电位.优化后的AgVO_(3)/TiO_(2)复合材料在没有任何助催化剂的情况下,表现出具有竞争力的光催化CO_(2)还原效率(CO,47.61μmol h-1g-1),是原始TiO_(2)NSs的20.97倍.本工作提出了一种直接Z型异质结的合理设计方法,为高效光催化CO_(2)还原催化剂的开发提供了指导.