Experimental comparison between corona and contact poling for EO polymer modulators

Two different poling techniques-corona poling and contact poling in the backdrop of electro-optic （EO） polymer modulators are compared. A 3-layer structure EO polymer modulator is prepared for the poling. The poling setups and procedures of these two different methods are given. It is found that a well-controlled precure step is very critical, otherwise it will result in either lower poling efficiency or damaged film. Experimental results show that contact poling does not create severe surface damage as corona poling and poling voltage is much lower, but corona poling provides higher EO effect than contact poling. Besides, contact poling can provide poling size as large as the substrate size.

STUDY ON THE POLING PROPERTIES OF NONLINEAR OPTICAL ACTIVE DERIVATIVE OF POLY (p-HYDROXYSTYRENE):(PS)O-DCV

In this paper, the poling properties of (PS)O-DCV, a derivative of poly (p-hydroxystyrene ), was reported. The investigations showed that the thermochromism correction, which was neglected in the literatures, should be considered in the measurements of order parameter of poled films with electrochromism technique Here, another linear optical method, IR and polarized IR spectra for characterizing of poled films was suggested first time. The bulk second nonlinear optical coefficient d_(33) of poled films could be estimated by measured order parameter semi-qualitatively.

An Investigation into the Role of Capping on Second Harmonic Generation from Nonlinear Organic Polymer and Guest-Host Thin Films by In-Situ Poling

In attempts to fabricate thermally stable second-order nonlinear polymer thin films, we have investigated the second harmonic generation (SHG) from both nonlinear polymer and guest-host thin films. We have also investigated the role of capping on the SHG, temporal stability and relaxation of dipole alignment. Corona poling techniques were employed to orient the dopants into the noncentrosymmetric structure required to obtain the SHG. The effect of capping with a polymeric encapsulant below the glass transition temperature of the polymers on the unpoled and corona poled thin films was studied. Capping of the nonlinear polymer and guest host thin films have resulted in high SHG with good temporal stability. SHG signal falls drastically during the first 8 days after poling while no further significant decay in SHG signal was observed after about 33 days. Our investigations have identified the characteristics required for a good encapsulant on a non-con-ductive surface.

Fabrication of Conductive Domain Walls in x-cut Congruent Thin-film Lithium Niobate Using an Electrical-field Poling Technique(Invited)

Conductive ferroelectric domain walls have attracted increasing research interest in the field of nanoelectronics,and the fabrication technique for such domain walls is vital.In this study,we investigated in detail the fabrication of conductive domain walls in x-cut congruent thin-film lithium niobate(TFLN)using an electrical-field poling technique.The ferroelectric domain structures can be controlled through the applied electrical field and applied pulse numbers,and the domain inversion process is related to the conduction characteristics of the domain walls.The domain structures in TFLN are revealed using confocal second-harmonic microscopy and piezoresponse force microscopy.The results provide further directions for the development and application of conductive domain walls in TFLN.

Enhanced piezoelectricity in 0.7BiFeO_(3)-0.3BaTiO_(3)lead-free ceramics:Distinct effect of poling engineering

BiFeO_(3)-BaTiO_(3) based ceramics are considered to be the most promising lead-free piezoelectric ceramics due to their large piezoelectric response and high Curie temperature.Since the piezoelectric response of piezoelectric ceramics just appears after poling engineering,in this work,the domain evolution and microscopic piezoresponse were observed in-situ using piezoresponse force microscopy(PFM)and switching spectroscopy piezoresponse force microscopy(SS-PFM),which can effectively study the local switching characteristics of ferroelectric materials especially at the nanoscale.The new domain nucleation preferentially forms at the boundary of the relative polarization region and expands laterally with the increase of bias voltage and temperature.The maximum piezoresponse(Rs),remnant piezoresponse(Rrem),maximum displacement(Dmax)and negative displacement(Dneg)at 45 V and 120C reach 122,69,127 pm and 75 pm,respectively.Due to the distinct effect of poling engineering in full domain switching,the corresponding d33 at 50 kV/cm and 120C reaches a maximum of 205 pC/N,which is nearly twice as high as that at room temperature.Studying the evolution of ferroelectric domains in the poling engineering of BiFeO_(3)-BaTiO_(3)ceramics provides an insight into the relationship between domain structure and piezoelectric response,which has implications for other piezoelectric ceramics as well.

Nonlinear optical polyimide with high thermal stability prepared by simultaneous poling and polymerization

The high Tg polyimide embedded with a novel imidazol-typed chromophore 2-[5-(4-nitrostilbenyl)thienyl]-4,S-di(4-aniinophenyl)imidazole (NSTDAPI) was prepared using the 'simultaneous poling and polymerization' technique. The glass transition temperature (Fg) is 304℃ and the initial decomposition temperature (Td) is 330℃. The in-situ second harmonic generation (in-situ SHG) measurement was performed to study its poling behavior and the stability of the poling-induced orientation. The nonlinear optical (NLO) coefficient d33 of poled polyimide film is 32.2 pm/V at 1064 nm fundamental wavelength. The SHG signal of the poled polymer film was quite stable below 200℃, and then began to decay rapidly above 220℃. The half-decay temperature of dipole orientation for the film is 250℃.

具有POLE致病性突变子宫内膜癌的临床病理及分子特征分析

目的探讨具有POLE致病性突变子宫内膜癌(EC)的临床病理及分子特征。方法选取179例EC患者,根据POLE基因突变、错配修复(MMR)蛋白表达及p53表达/TP53突变进行分子分型,分析POLE mut型EC的临床病理及分子特征。结果POLE mut20例,MMRd 48例,NSMP 90例,p53 abn 21例。POLE mut EC多为FIGOⅠ期(17/20),中-低分化子宫内膜样癌(EEC)(13/20)、局限于内膜/浅肌层(17/20)、肿瘤浸润性淋巴细胞(TILs)显著(17/20)、无/局灶(LVSI)(18/20)、无淋巴结转移(19/20)。4个亚组间临床病理特征的差异均有统计学意义(P<0.05)。POLE mut型预后最好,具有多重分类特征的病例预后更接近POLE mut型。结论POLE mut EC提示着较高的组织学分级,较早的临床分期及较好的预后;POLE mut可继发dMMR/MSI-H表型及p53/TP53异常,应归类为POLE mut型。

High temperature and low voltage AC poling for 0.24Pb(In_(1/2)Nb_(1/2))O_(3)- 0.46Pb(Mg_(1/3)Nb_(2/3))O_(3)-0.30PbTiO_(3) piezoelectric single crystals manufactured by continuous-feeding Bridgman method

Alternating current poling(ACP)in air by changing poling temperature(70e130℃)and voltages(2e6 kVrms/cm)on pseudo-ternary 0.24 Pb(In_(1/2)Nb_(1/2))O_(3)-0.46 Pb(Mg1/3Nb_(2/3))O3-0.30PbTiO_(3)(PIMN-0.30PT)single crystals(SCs)manufactured by continuous-feeding Bridgman(CF BM)method was investigated.Free dielectric permittivity(εT 33/ε0)and piezoelectric constant(d33)were improved to be 7000 and 2340 pC/N,which were 29%higher than those of direct current poling(DCP)at 90℃ with 4 kV/cm(εT 33/ε0=5440,d_(33)=1810 pC/N).However,phase change temperature(Tpc)decreased from 94℃ to 78℃ as opposite results reported by other groups.We demonstrated that the high temperature(HT)ACP improved piezoelectric performance of CF BM SCs,however,the Tpc were different from other crystal growth method.The well-designed ACP process was a promising method for mass production not only to enhance the electrical properties for the pseudo-ternary SCs but also reduce the risk of breakdown and realizes organic solvent-free poling process.

PolinGer治疗仪配合中药对提高产后泌乳量的研究

目的探讨PolinGer治疗仪配合中药对提高产妇泌乳量的效果。方法选择305例产后乳汁不足患者,随机分为3组:单纯中药治疗组(对照1组)93例,采用口服通乳汤治疗;单纯PolinGer治疗仪理疗组(对照2组)84例;PolinGer治疗仪配合中药治疗组(治疗组)128例。比较三种方法的疗效及平均治疗时间,同时观察不同时机治疗效果的差异。结果产后乳汁不足患者其PolinGer治疗仪配合中药治疗组的疗效明显高于对照组,且患者平均治疗时间较对照组短;产后14 d内较产后超过14 d治疗的患者效果显著,差异有统计学意义(P<0.05)。结论PolinGer治疗仪配合中药治疗提高产后泌乳量比单纯中药治疗和单纯PolinGer治疗仪理疗效果好。

High-performance and high-thermally stable PSN-PZT piezoelectric ceramics achieved by high-temperature poling

High piezoelectric properties and superior thermal stability are both important indicators of piezoelectric ceramics serving at high temperature.However,since these properties are usually mutually exclusive,high performance and superior thermal stability are hard to achieve simultaneously.Here we report that a high piezoelectricity(d_(33)∼562 pC/N)and superior thermal stability(the variation is within 7%from 20 to 330℃)were both achieved in 0.4 mol%ZnO-doped 0.02Pb(Sb_(1/2)Nb_(1/2))-0.51PbZrO_(3)-0.47PbTiO_(3) by high-temperature poling.Compared with traditional poling method,high-temperature poling method forms a small-sized and highly oriented domain structure,which can effectively improve the piezoelectric and dielectric properties of piezoelectric ceramics.At the same time,the enhanced pinning effect of defect ions and stabilized domain structure due to high-temperature poling also contribute to the superior temperature stability of the piezoelectric and dielectric properties.This work provides an effective method for designing piezoelectric materials with high performance and good temperature stability for high temperature sensor applications.

Spurious-mode vibrations caused by alternating current poling and their solution process for Pb(Mg_(1/3)Nb_(2/3))O_(3)-PbTiO_(3) single crystals

The effects of alternating current poling(ACP)at 80℃on electrical properties of[001]-oriented 0.72 Pb(Mg_(1/3)Nb_(2/3))O_(3)-0.28PbTiO_(3)(PMN-28PT)single crystals(SCs)have been investigated.The square-wave ACP SCs poled at high voltage(HV,5 kV_(rms)/cm)occasionally showed large fluctuations and low opposite values of piezoelectric coefficient(d_(33)=±1370 pC/N)in one plate.This revealed spuriousmode vibrations(SMV)of impedance spectrum.However,after depolarizing and repolarizing the sample with a sine-wave ACP at low voltage(LV,3.5 kV_(rms)/cm),the d_(33) enhanced to be 1720 pC/N(+26%)and did not exhibit large fluctuation or opposite values in one plate any more.The impedance spectrum became clean and the abnormal SMV disappeared.We proposed four possible mechanisms of the SMV,and speculate that the main cause maybe by macro-scale sub-domain structure and/or phase change in the main domain structure and/or phase in the SC plate due to the specific poling conditions not eternal mechanical damage of PMN-PT SCs.This study will be useful to realize a high d_(33) and improve other properties of PMN-PT ACP SC ultrasonic transducers without any SMV for high-frequency medical imaging equipment.

Five-phase Synchronous Reluctance Machines Equipped with a Novel Type of Fractional Slot Winding

Multi-phase machines are so attractive for electrical machine designers because of their valuable advantages such as high reliability and fault tolerant ability.Meanwhile,fractional slot concentrated windings(FSCW)are well known because of short end winding length,simple structure,field weakening sufficiency,fault tolerant capability and higher slot fill factor.The five-phase machines equipped with FSCW,are very good candidates for the purpose of designing motors for high reliable applications,like electric cars,major transporting buses,high speed trains and massive trucks.But,in comparison to the general distributed windings,the FSCWs contain high magnetomotive force(MMF)space harmonic contents,which cause unwanted effects on the machine ability,such as localized iron saturation and core losses.This manuscript introduces several new five-phase fractional slot winding layouts,by the means of slot shifting concept in order to design the new types of synchronous reluctance motors(SynRels).In order to examine the proposed winding’s performances,three sample machines are designed as case studies,and analytical study and finite element analysis(FEA)is used for validation.

Progress of International Meridian Circle Program

In 2024,the Chinese Meridian Project(CMP)completed its construction,deploying 282 instruments across 31 stations.This achievement not only provides a robust foundation but also serves as a reference template for the International Meridian Circle Program(IMCP).The IMCP aims to integrate and establish a comprehensive network of ground-based monitoring stations designed to track the propagation of space weather events from the Sun to Earth.Additionally,it monitors various disturbances generated within the Earth system that impact geospace.Over the past two years,significant progress has been made on the IMCP.In particular,the second phase of construction for the China-Brazil Joint Laboratory for Space Weather has been completed,and the North Pole and Southeast Asia networks are under active construction.The 2024 IMCP joint observation campaign was successfully conducted.To facilitate these developments,the scientific program committee of IMCP was established,following the success of 2023 IMCP workshop and the space weather school,which was co-hosted with the Asia-Pacific Space Cooperation Organization(APSCO)and sponsored by Chinese Academy of Sciences(CAS)and Scientific Committee on Solar-Terrestrial Physics(SCOSTEP).Preparations are now underway for the 2024 workshop in collaboration with the National Institute for Space Research(INPE)in Brazil.

Theoretical analysis of thermal/electric-filed poling silica glass

Based on the experimental results, three basic conclusions are summarized for the thermal/electric-field poling (TEFP) silica materials, with which the second-order nonlinear optical coefficient in the bulk silica glass after TEFP is calculated, and relationships between the coefficient and the applied voltage V 0 in the poling process and the thickness of the nonlinear layer created from the poling are obtained. Theoretical results show that the second-order susceptibility χ(2) and the second-harmonic efficiency η in the poled bulk glass are proportional to √V 0 and V 0 2 , respectively; χ(2)～0.2?1.6 pm/V for the bulk glass after the typical TEFP; χ(2) decreases with an increase in the poling time after the TEFP silica glass approximately reaches the steady state. Theoretical results are well consistent with the experimental reports.

子宫内膜癌分子分型的研究进展

子宫内膜癌是女性生殖系统常见的恶性肿瘤,临床工作根据形态学特点及激素依赖性将其分为两个亚型,即激素依赖型和非激素依赖型。2013年癌症基因组图谱网络根据不同的分子特征将子宫内膜癌分为4个分子亚型,即POLE突变型、微卫星不稳定型、低拷贝数变异型、高拷贝数变异型。但该分组方法需要基因组测序,成本昂贵、操作复杂,不适合广泛的临床应用。因此,在这个分子分型的基础上MC Alpine团队在2015年对该方法进行改良,提出子宫内膜癌的主动分子风险分类器,并在2018年确定分类器的最终验证步骤。这个主动分子风险分类器已被广泛应用。

TIME AND POLING HISTORY DEPENDENT ENERGY STORAGE AND DISCHARGE BEHAVIORS IN POLY(VINYLIDENE FLUORIDE-CO-HEXAFLUOROPROPYLENE) RANDOM COPOLYMERS

We studied cycle time （0.01-10 s with triangular input waves） and poling history （continuous versus fresh poling） dependent electric energy storage and discharge behaviors in poly（vinylidene fluoride-co-hexafluoropropylene） [P（VDF- HFP）] films using the electric displacement -- the electric field （D-E） hysteresis loop measurements. Since the permanent dipoles in PVDF are orientational in nature, it is generally considered that both charging and discharging processes should be time and poling history dependent. Intriguingly, our experimental results showed that the charging process depended heavily on the cycle time and the prior poling history, and thus the D-E hysteresis loops had different shapes accordingly. However, the discharged energy density did not change no matter how the D-E loop shape varied due to different measurements. This experimental result could be explained in terms of reversible and irreversible polarizations. The reversible polarization could be charged and discharged fairly quickly （〈 5 ms for each process）, while the irreversible polarization depended heavily on the poling time and the prior poling history. This study suggests that it is only meaningful to compare the discharged energy density for PVDF and its copolymer films when different cycle times and poling histories are used.

Evolution of domain structure in 0.96(K_(0.48)Na_(0.52))(Nb_(0.96)Sb_(0.04))O_(3)0.04(Bi_(0.50)Na_(0.50))ZrO_(3) ceramics with poling and temperature

Domain structure often has significant influences on both piezoelectric properties and piezoelectric temperature stability of a ferroelectric ceramic.In-depth studies on the characters of domain structure should be helpful for the better understanding of piezoelectric performance.In this work,the evolution of domain structure in large-d_(33)0.96(K_(0.48)Na_(0.52))(Nb_(0.96)Sb_(0.04))O_(3)-0.04(Bi_(0.50)Na_(0.50))ZrO_(3) ceramics with poling and temperature was systematically investigated via comparing the various domain patterns that are obtained by acid-etching.It was found that domain structure changes greatly upon poling and varies largely with temperature.Complex domain patterns consisting of long narrow parallel stripes or herringbone structure separated by 180°domain boundaries are observed in the unpoled ceramics at room temperature.Domain patterns become less complicated upon poling,due to the collective polarization reversals of parallel-stripe domain clusters and banded fine-stripe domain segments.Parallel stripes and herringbone bands become much wider upon poling,as some narrow stripes and herringbone bands coalesce into broad ones,respectively.Hierarchical domain structure is commonly seen in the domain patterns acid-etched at room temperature,but is less frequently recognized at elevated temperatures.Schematic models of domain configurations were proposed to explain the domain structure and its evolution with poling.

High piezoelectricity after field cooling AC poling in temperature stable ternary single crystals manufactured by continuous-feeding Bridgman method

After field cooling(FC)alternating current poling(ACP),we investigated the dielectric and piezoelectric properties of[001]_(pc)-oriented 0.24Pb(In_(1/2)Nb_(1/2))O_(3)(PIN)-0.46Pb(Mg_(1/3)Nb_(2/3))O_(3)(PMN)-0.30PbTiO3(PT)(PIMN-0.30PT)single crystals(SCs),which were manufactured by continuous-feeding Bridgman(CF BM)within morphotropic phase boundary(MPB)region.By ACP with 4 kVrms/cm from 100 to 70℃,the PIMN-0.30PT SC attained high dielectric permittivity of 8330,piezoelectric coefficient(d_(33))of 2750 pC/N,bar mode electromechanical coupling factorκ_(33)of 0.96 with higher phase change temperature(T_(pc))of 103℃,and high Curie temperature(7c)of 180℃.These values are the highest ever reported as PIMN-xPT SC system with Tpc>100℃.The enhancement of these properties is attributed to the induced low symmetry multi-phase supported by phase analysis.This work indicates that FC ACP is a smart and promising method to enhance piezoelectric properties of relaxor-PT ferroelectric SCs including PIMN-xPT,and provides a route to a wide range of piezoelectric device applications.

Effectiveness of Chromated Copper Arsenate against Deteriorating Agents of Eucalyptus Poles and Posts in Four Eco-Regions in Kenya

Previous studies done elsewhere have shown that Eucalyptus poles treated with chromated copper arsenate (CCA) can last over 30 years. Kenya is exceptional because in some eco-regions, the Eucalyptus poles’ life span has greatly reduced to 5 years. The current study was designed to evaluate wood deteriorating agents of CCA-treated Eucalyptus poles and variability in four eco-regions of Kenya, namely, dryland, coastal, highland and humid lake. A total of 360 Eucalyptus pole samples were used for this experiment. Three CCA treatments were used to treat transmission poles at 20 kg/cm3 fencing posts samples at 6 kg/cm3, and a control group. Results indicated that termites and wood-decay fungi attacks caused wood deterioration in the four eco-regions. The proportion of power transmission pole degradation by wood deteriorating agents varied across eco-regions, between treatments and control and between time after treatments. Dryland eco-regions had the highest termite-related degradation (41.82%) while wood-decay fungi attack was highest in the highland eco-regions (9.20%). Samples treated with 6 kg/cm3 recorded the lowest level of wood deterioration, manifested by minimal superficial termite and wood-decay fungi attack. Samples treated with 20 kg/cm3 were characterized by moderate termite and wood-decay fungi attacks observed around the heartwood region, unlike sapwood. This study concluded that the deterioration of Eucalyptus CCA-treated poles is a question of climatic variability and hence, to increase the poles’ lifespan, CCA treatment should be tailored according to the characteristics of the ecoregion of use. Further investigations will inform the diversity of termites and decay-fungi across different eco-regions.

The Performance of Small Diameter Aluminum Light Support Structures Containing Handholes under Cyclic Fatigue

Aluminum light poles play a pivotal role in modern infrastructure, ensuring proper illumination along highways and in populated areas during nighttime. These poles typically feature handholes near their bases, providing access to electrical wiring for installation and maintenance. While essential for functionality, these handholes introduce a vulnerability to the overall structure, making them a potential failure point. Although prior research and analyses on aluminum light poles have been conducted, the behavior of smaller diameter poles containing handholes remains unexplored. Recognizing this need, a research team at the University of Akron undertook a comprehensive experimental program involving aluminum light poles with handholes containing welded inserts in order to gain a better understanding of their fatigue life, mechanical behavior, and failure mechanisms. The research involved testing seven large-scale aluminum light poles each 8-inch diameter, with two separate handholes. These handholes included a reinforcement that was welded to the poles. Finite Element Analysis (FEA), statistical analysis, and comparison analysis with their large counterparts (10-inch diameter) were used to augment the experimental results. The results revealed two distinct failure modes: progressive crack propagation leading to ultimate failure, and rupture of the pole near the weld initiation/termination site around the handhole. The comparison analysis indicated that the 8-inch diameter specimens exhibited an average fatigue life exceeding that of their 10-inch counterparts by an average of 30.7%. The experimental results were plotted alongside the fatigue detail classifications outlined in the Aluminum Design Manual (ADM), enhancing understanding of the fatigue detail category of the respective poles/handholes.