An Improved Preisach Distribution Function Identification Method Considering the Reversible Magnetization

This paper presents an identification method of the scalar Preisach model to consider the effect of reversible magnetization in the process of distribution function identification.By reconsidering the identification process by stripping the influence of reversible components from the measurement data,the Preisach distribution function is identified by the pure irreversible components.In this way,the simulation accuracy of both limiting hysteresis loops and the inner internal symmetrical small hysteresis loop is ensured.Furthermore,through a discrete Preisach plane with a hybrid discretization method,the irreversible magnetic flux density components are computed more efficiently through the improved Preisach model.Finally,the proposed method results are compared with the traditional method and the traditional method considering reversible magnetization and validated by the laboratory test for the B30P105 electrical steel by Epstein frame.

Determinants of Long Acting Reversible Contraception Method Use among Mothers in Extended Postpartum Period, Durame Town, Southern Ethiopia: A Cross Sectional Community Based Survey

Background: After a live birth, there is much unsatisfied interest in, and unmet family planning need for contraception. Waiting at least for 24 months before attempting the next pregnancy was recommended to reduce the risk of adverse maternal, perinatal and infant outcomes. The purpose of this study was to assess the determinants of long acting reversible contraception method use among mothers in extended postpartum period in Durame Town, Southern Ethiopia. Methods: A community based cross sectional study was conducted in Durame Town, Southern Ethiopia in December, 2014. Systematic random sampling technique was employed to recruit a total 460 study participants. Structured and pretested questioner was used to collect the data. Descriptive statistics was employed to characterize the study population using frequencies and proportions. Bivariate logistic regression analysis was conducted to identify all possible factors affecting utilization of LARC method. Multivariable logistic regression model was developed to control the confounding variables. Adjusted Odds Ratio (AOR) with 95% Confidence Interval (CI) was computed in identifying the real factors associated with use of LARC methods. Results: In this study we found that the prevalence of LARC method use among mothers during their extended postpartum period was 36.7% (95%CI: 32.2, 41.0). The unmet family planning need of mothers in the extended postpartum period was 123 (27.9%). The odds of using LARC by literate mother were four fold higher than their counterpart illiterate mothers (AOR 4.09 95%CI: 1.68, 9.58, P value < 0.001). The odds of mother who had pervious experiences of using LARC were up to eight folds higher than mother never used LARC methods (AOR 7.84 95% CI: 3.78, 16.23, P value< 0.001). Mother who received counseling service on LARC methods during delivery was up to three times more likely to utilize the services than not counseled (AOR 3.29 95% CI: 1.53, 7.03, P value < 0.001). And odds of mothers who received counseling service on LARC during immediate postpartum period were up to five fold more likely to opt method than never got the counseling service (AOR 4.55 95 % CI: 1.94, 10.66, P value < 0.001). Conclusions: In the study area, about one third of mothers utilized LARC methods during their extended postpartum period. Another one third of mother had unmet need for family planning. Participant’s education, previous history of using LARC methods, receiving counseling services on LARC during delivery and immediate postpartum periods were found major determinant for LARC use. Educating women, providing counseling service on LARC methods during antenatal, delivery and postnatal were recommended.

The Inheritance and Application of Chinese Reverse Contrast Typeface Style

This paper discusses the inheritance and application of Chinese character reverse contrast typeface style.It begins by analyzing the visual features of Western reverse contrast typeface styles,with a focus on Caslon Italian and French Clarendon,providing a Western perspective reference for subsequent Chinese character reverse contrast typeface style designs.The paper then traces the origins of the Chinese reverse contrast style,from the calligraphy style"Lacquer Script"to the earliest printing type"フワンテール形",exploring the historical background and cultural significance of the Chinese reverse contrast style.In the methodology section of Chinese character reverse contrast typeface style design,the discussion is conducted from two dimensions:inheritance and application.In terms of inheritance,through an in-depth analysis of"Lacquer Script"and"フワンテール形"typeface style,the paper summarizes three basic theories for modern Chinese character reverse contrast typeface style design.In the application section,it examines in detail the two most influential recent typeface styles,"Ribaasu"and"Basic Artistic",outlining three directions of application:extreme horizontal stroke variations,exaggerated contrast,and diverse decorative strokes,showcasing new directions and possibilities for Chinese character reverse contrast typeface style design.This paper not only reviews the developmental history of the Chinese character reverse contrast typeface style but also analyzes the design methodology of Chinese character reverse contrast typeface style through specific case studies.

Large-Scale and Reversible Synthesis of Bright Upconversion Crystals with Almost 100%Yield by a Minimalist Method for Recyclable Application

Upconversion luminescence(UCL)materials have the potential for many applications due to their unique optical properties.Some technical challenges such as complex synthesis with low yield and nondegradability need to be addressed for practical use.Here,we report for the first time a minimalist method for large-scale synthesis of Cs_(2)NaErCl_(6)UCL crystals with almost 100%yield,simply by dissolving metal chlorides in water and then drying,referred to as the“dissolve-dry”method.Cs_(2)NaErCl_(6)crystals produced under such mild conditions exhibited bright UCL at either 808 or 980 nm irradiation.UCL was achieved through an excited state absorption process,and the excellent performance was mainly attributed to the large unit cells of the crystals and the long lifetime of Er^(3+)excited energy levels.Moreover,the synthesis was reversible and could be scaled up unlimitedly,making it suitable for industrial applications,with recyclable products.The recyclable application of Cs_(2)NaErCl_(6)crystals as a luminescent medium in near-infrared light-emitting diode excitable upconversion devices was demonstrated based on its excellent recyclability.Our work not only provides a new strategy for large-scale synthesis of UCL crystals but also demonstrates the recyclability of this material and its related applications.

FINITE ELEMENT NUMERICAL SIMULATION OF TEMPERATURE FIELD IN METAL PATTERN CASTING SYSTEM AND "REVERSE METHOD" OF DEFINING THE THERMAL PHYSICAL COEFFICIENT

With the technology support of virtual reality and ANSYS software, an example on the simulation of temperature distribution of casting system during the solidification process was provided, which took the latent heat of phase change, the conditions for convection, and the interface heat transfer coefficient into consideration. The result of ANSYS was found to agree well with the test data. This research offers an unorthodox way or ＂reverse method＂ of defining the relevant thermal physical coefficient.

LEAST-SQUARES METHOD-BASED FEATURE FITTING AND EXTRACTION IN REVERSE ENGINEERING

The main purpose of reverse engineering is to convert discrete data pointsinto piecewise smooth, continuous surface models. Before carrying out model reconstruction it issignificant to extract geometric features because the quality of modeling greatly depends on therepresentation of features. Some fitting techniques of natural quadric surfaces with least-squaresmethod are described. And these techniques can be directly used to extract quadric surfaces featuresduring the process of segmentation for point cloud.

Efficient hybrid method for time reversal superresolution imaging

An efficient hybrid time reversal（TR） imaging method based on signal subspace and noise subspace is proposed for electromagnetic superresolution detecting and imaging. First, the locations of targets are estimated by the transmitting-mode decomposition of the TR operator（DORT） method employing the signal subspace. Then, the TR multiple signal classification（TR-MUSIC）method employing the noise subspace is used in the estimated target area to get the superresolution imaging of targets. Two examples with homogeneous and inhomogeneous background mediums are considered, respectively. The results show that the proposed hybrid method has advantages in CPU time and memory cost because of the combination of rough and fine imaging.

Preparation of CaP/pDNA nanoparticles by reverse micro-emulsion method: Optimization of formulation variables using experimental design

In this study, the CaP/pDNA nanoparticles were prepared using Triton X-100/Butanol/Cyclohexane/Water reverse microemulsion system. Optimization of preparation conditions was based on evaluation of particle size by Box–Behnken design method. The particle sizes of the optimized CaP/pDNA nanoparticles were found to be 60.23 ± 4.72 nm, polydispersity index was 0.252 and pDNA encapsulate efficiency was more than 90%. The optimized CaP/pDNA nanoparticles have pH sensitivity and biocompatibility. Further, optimized CaP/pDNA nanoparticles showed higher transfection efficiency.

Computational Fluid Dynamics(CFD) Analysis and Optimization of Reconstructed Intake System of Cylinder Head Based on Slicing Reverse Method

To find out and improve the flow characteristics inside the intake system of cylinder head,the application of computational fluid dynamics(CFD)in the evaluation and optimization of the reconstructed intake system based on slicing reverse method was proposed.The flow characteristics were found out through CFD,and the velocity vector field,pressure field and turbulent kinetic energy field for different valve lifts were discussed,which were in good agreement with experimental data,and the quality of reconstruction was evaluated.In order to improve its flow characteristic,an optimization plan was proposed.The results show that the flow characteristics after optimization are obviously improved.The results can provide a reference for the design and optimization of the intake system of cylinder head.

A General Framework of Reversible Data Hiding with Controlled Contrast Enhancement

This paper proposes a two-step general framework for reversible data hiding(RDH)schemes with controllable contrast enhancement.The first step aims at preserving visual perception as much as possible on the basis of achieving high embedding capacity(EC),while the second step is used for increasing image contrast.In the second step,some peak-pairs are utilized so that the histogram of pixel values is modified to perform histogram equalization(HE),which would lead to the image contrast enhancement.However,for HE,the utilization of some peak-pairs easily leads to over-enhanced image contrast when a large number of bits are embedded.Therefore,in our proposed framework,contrast over-enhancement is avoided by controlling the degree of contrast enhancement.Since the second step can only provide a small amount of data due to controlled contrast enhancement,the first one helps to achieve a large amount of data without degrading visual quality.Any RDH method which can achieve high EC while preserve good visual quality,can be selected for the first step.In fact,Gao et al.’s method is a special case of our proposed framework.In addition,two simple and commonly-used RDH methods are also introduced to further demonstrate the generalization of our framework.

A Stability Indicating Reverse Phase-HPLC Method Development and Validation for the Estimation of Rucaparib in Bulk and Pharmaceutical Dosage Form

The research was carried out for establishing a new reverse phase-HPLC stability indicating method for the quantification of Rucaparib. The experiment was determined on Waters HPLC instrument using 996 photo-diode array detector. The separation was done by using symmetry C-18 ODS (25 cm × 0.46 cm internal diameter) 5 μm analytical column containing mobile phase of Phosphate buffer (0.02 M) and methanol [65:35% v/v] adjusted pH to 4.8 by adding dilute ortho phosphoric acid. The method was run at 1 ml·min-1 at 286 nm detection. The drug was eluted at 5.484 min. After developing the method, it was assured for the intended use by validation which was done according to ICH Q2B guidelines. The analytical parameters checked were linearity, accuracy, repeatability, intermediate precision, limit of detection, limit of quantitation, ruggedness and robustness. It was observed that the response of the detector was linear in the range of 6 - 14 μg/ml with correlation coefficient of 0.999. The results of all the parameters were found to be within the acceptance criteria. The stability indicating assay method was established by using the samples generated by forced degradation process. The forced degradation was carried out by subjecting the drug to acid, alkali, thermal, oxidative and photolytic degradation and the results showed that the degradation products were successfully separated from the drug. Hence, this can be applied perfectly later for the analysis of quality of the rucaparib drug.

Stable attenuation-compensated reverse time migration and its application to land seismic data

Intrinsic attenuation of the earth causes energy loss and phase distortion in seismic wave propagation.To obtain high-resolution imaging results,these negative effects must be considered during reverse time migration(RTM).We can easily implement attenuation-compensated RTM using the constant Q viscoacoustic wave equation with decoupled amplitude attenuation and phase dispersion terms.However,the nonphysical amplitude-compensation process will inevitably amplify the high-frequency noise in the wavefield in an exponential form,causing the numerical simulation to become unstable.This is due to the fact that the amplitude of the compensation grows exponentially with frequency.In order to achieve stable attenuation-compensated RTM,we modify the analytic expression of the attenuation compensation extrapolation operator and make it only compensate for amplitude loss within the effective frequency band.Based on this modified analytic formula,we then derive an explicit time-space domain attenuation compensation extrapolation operator.Finally,the implementation procedure of stable attenuation-compensated RTM is presented.In addition to being simple to implement,the newly proposed attenuation-compensated extrapolation operator is superior to the conventional low-pass filter in suppressing random noise,which will further improve the imaging resolution.We use two synthetic and one land seismic datasets to verify the stability and effectiveness of the proposed attenuationcompensated RTM in improving imaging resolution in viscous media.

A Stability Indicating Reverse Phase-HPLC Method Development and Validation for the Estimation of Bimatoprost 0.3% &Timolol 0.5% Pharmaceutical Ophthalmic Dosage Form

The research was carried out to establish a new reverse phase-HPLC stability indicating method for quantifying Bimatoprost & Timolol in ophthalmic solution. The experiment of Bimatoprost & Timolol in ophthalmic solution method development was determined on Waters HPLC instrument using a UV Detector. The separation was done by using L11, Zorbex SB phenyl (4.6 mm × 250 mm internal diameter) 5 μm analytical column, containing mobile phase of Phosphate buffer (0.02 M), methanol, and acetonitrile [50:30:20 % v/v]. The method was run at 1 ml·min-1 at 210 nm for Bimatoprost and 295 nm for Timolol for detection. The drug was eluted at 10.81 min for Bimatoprost and 3.77 min for Timolol. After developing the method, it was assured for the intended use by validation, which was done according to ICH Q2B guidelines. The analytical parameters checked were Specificity/Selectivity, linearity, Range, accuracy, ruggedness, and robustness. It was observed that the response of the detector was linear in the range of 6 - 18 μg/ml with a correlation coefficient of 0.999. The results of all the parameters were found to be within the acceptance criteria. The stability-indicating assay method was established by using the samples generated by the forced degradation process. The forced degradation was carried out by subjecting the drug to acid, alkali, thermal, oxidative, and photolytic degradation, and the results showed that the degradation products were successfully separated from the drug. Hence, this can be applied perfectly later for the quantitative analysis of Bimatoprost 0.3% + Timolol 0.5% Ophthalmic Solution drugs for pharmaceutical use. Currently, there is no official method for Bimatoprost & Timolol combination products in USP or BP. Available research work related to single Bimatoprost or Timolol products was not suitable for testing Bimatoprost and Timolol combination drugs. Additionally, there is no stability-indicating method to test Bimatoprost & Timolol combination products which insist us to do research and develop a new reverse phase-HPLC indicating method which will be faster and more accurate.

钻井法凿井气-液-固耦合排渣流场及刀盘吸渣口优化

针对西部地区侏罗系地层煤矿立井钻井法施工中出现的气举反循环洗井排渣与钻进效率低下问题,以陕西可可盖煤矿中央回风立井ϕ4.2 m超前钻井为工程背景,基于CFD-DEM(计算流体力学和离散单元法耦合)研究方法,建立了气-液-固多相耦合排渣数值模型,揭示了排渣管内、井底流场的速度及压力分布规律,并基于自研的气举反循环排渣试验装置,采用PIV(粒子图像测速法)测试技术对流场分布的正确性进行验证;提出了优化刀盘吸渣口评判指标和方法,对吸渣口的数量、长径比、面积比、总面积占比进行优化,得到了超前钻头刀盘吸渣口布置的最佳方式和相关参数;讨论了钻头转速、注气量、风管没入比和泥浆黏度等主要因素对排渣流场的影响。研究结果表明:(1)排渣管内流体的运移以轴向流动为主,且途经注气端时,流速发生跳跃式剧增;井底流体的运移主要以水平流动为主,流体的垂直上返仅存在于吸渣口附近;井底流体的水平流动以切向流动为主,径向流动仅在吸渣口两侧较为明显,且远离吸渣口处,径流速度较小易产生岩屑沉积;(2)当刀盘吸渣口数量为2,长径比为0.4,面积比为1,总面积占比为1.94%时,吸渣口的布置方式最佳,且清渣率较现行吸渣口布置方式提高66%;(3)增大钻头转速可显著增强吸渣口的吸附作用,注气量、风管没入比与井底和排渣管内流体的轴向速度均呈正相关关系,低黏、低密度的泥浆易获取高流速,但携岩能力较差。研究结果可为破解侏罗系地层深大立井钻井法洗井排渣与钻进效率低下技术难题,提供有益的理论参考。

贸易自由化与中国出口农产品质量:基于双边贸易成本的研究

出口农产品质量直接关系农产品出口的长远发展。基于双边贸易成本的视角,利用中国与127个贸易伙伴847种农产品的数据,运用回归反推法测算了中国出口农产品的质量水平,并从理论和实证两个方面分析了贸易自由化对中国出口农产品质量的影响。研究发现,样本期间,中国出口农产品质量呈波动上升趋势,且贸易自由化总体上可显著促进中国出口农产品质量的提高,但对出口到不同收入组国家农产品质量的影响存在显著差异。具体而言,贸易自由化对中国出口到埃塞俄比亚等低收入组国家农产品质量的促进作用最为显著,对出口到孟加拉等中等偏低收入组和日本高收入组国家农产品质量的促进作用次之,对出口到印度尼西亚等中等偏高收入组国家的农产品质量反而具有阻碍作用。

磁通反向永磁振镜电动机优化设计与分析

提出了一种具有不等定子齿宽的磁通反向永磁振镜电动机,通过敏感度分析,选取大定子齿宽、小定子齿宽、转子齿宽和槽肩宽4个参数作为影响因素,以转矩密度、转矩变化率、齿槽转矩和电感为优化目标,采用田口法进行正交试验分析,获得不同因素水平下的目标响应,并结合灰色关联法,将多目标优化转化为单目标优化问题,实现了电动机的最优设计.通过电动机性能的对比分析,验证了所设计的电动机的优越性和优化设计方法的有效性.

BPA可逆热敏变色复合材料制备方法及其应用研究进展

综述了BPA可逆热敏变色材料的制备及其应用,以及复配法、无机包覆法、微胶囊法、湿成膜法和近年来的2,6-单取代双酚A复合膜新方法,并分析了2,6-单取代法中膜结晶相变与二醛、酚醛树脂及胶种的关系。2,6-单取代双酚A线型或芳香酚醛树脂及其复合膜有机体系的设计与研究将进一步推动该类材料在具有可调的迟滞响应相变智能窗口,超低温变色敏感性、变色深度、稳定性,环境友好型合成树脂及塑料及实验教学等方面的应用。

基于ABAQUS的木梁损伤识别仿真研究

采用ABAQUS和压电时间反演技术对带裂缝木梁进行损伤识别数值仿真分析和试验验证研究,提出了基于时间反演聚焦信号峰值的损伤指数D1和基于时间反演重构信号和激励信号相关系数的损伤指数D2,以进行损伤识别定量评估。研究表明:聚焦信号峰值、重构信号和激励信号的相关系数均与损伤程度密切相关,两个损伤指数均随损伤程度的增加而增大;时间反演法具有良好的自适应聚焦效果,利用压电时间反演技术可有效识别木梁不同程度的裂缝损伤。研究结果可为工程实际提供参考。

基于逆向工程法培养小学生微创新能力的实践研究——以“3D打印”为例

逆向工程法是一种“从成品出发”的教学方法,降低了创新门槛,容易实现微创新。文章以微创新能力内涵为导向,遵循“从仿到创”的阶段式教学理念,在项目式教学理论、做中学理论的支持下,提出了基于逆向工程法培养小学生微创新能力的教学活动框架,以“3D打印”为例进行三轮教学实践,并采用三角互证的方法从教师、学生、教学过程三个角度探究实践效果,以此修正与完善活动框架。研究结果表明,基于逆向工程法设计的教学活动从总体上显著提高了小学生微创新能力水平,对创新思维与创新技能要素也有显著促进作用,但对创新人格的影响不显著。研究结果为小学生微创新能力培养及国家创新人才培养提供了理论指导和实践参考。

计算长度反推法在钢压杆整体稳定试验中的应用

钢压杆的整体稳定承载力与构件的初始几何缺陷、残余应力、钢材弹塑性以及端部的约束情况密切相关。试验观测表明,实际测得的压杆稳定极限承载力高于按压杆几何长度确定的屈曲荷载。这主要是由于压杆两端支座实际上很难达到理想的铰接状态,较强的支座约束情况引起构件计算长度取值变小,钢压杆的稳定极限承载力随之提高。根据传统的构件稳定理论,利用了压杆整体稳定承载力试验弹性阶段的荷载-位移关系,提出了一种反推计算长度的方法。借助可靠的有限元模型分析验证了该方法的正确性。将此方法应用于实际的钢压杆整体稳定承载力试验数据分析,不仅合理解释了试验现象与结果,还消除了不同支座形式对钢压杆整体稳定承载力大小的影响。相关结论可为钢压杆整体稳定承载力试验研究提供参考。