Convergence Issues Associated with Cutoff Energies and Ab Initio Studies of Adsorption of CO on W and Pt

The experimental research programs of 1950s, to understand the adsorption of CO on W surfaces, changed to ab initio studies in 2000s. The goals were to seek improved practical applications. Most of the studies were based on density functional theory. Many studies also used programs, such as VASP (Vienna Abinitio simulation package) and CPMD. The computational procedures used plane wave approximations. This needed studies with selection of K points and cutoff energy selection to assure convergence in energy calculations. Observations and analysis of papers published from 2006 to 2022 indicate that the cutoff energies were selected arbitrarily without any needed convergence studies. By selecting a published 2006 paper, this paper has clearly showed that an arbitrary selection of cutoff energy, such as 460 eV, is not in the range of, cutoff energies that assure convergence of energy calculations, with ab initio methods and have indicated correction procedures. .

Wave Azimuth Cutoff Compensation Method and the Multisatellite Networking Mode of SAR

Synthetic aperture radars(SARs)encounter the azimuth cutoff problem when observing sea waves.Consequently,SARs can only capture the waves with wavelengths larger than the cutoff wavelength and lose the information of waves with smaller wavelengths.To increase the accuracy of SAR wave observations,this paper investigates an azimuth cutoff compensation method based on the simulated multiview SAR wave synchronization data obtained by the collaborative observation via networked satellites.Based on the simulated data and the equivalent multiview measured data from Sentinel-1 virtual networking,the method is verified and the cutoff wavelengths decrease by 16.40%and 14.00%.The biases of the inversion significant wave height with true values decrease by 0.04 m and 0.14 m,and the biases of the mean wave period decrease by 0.17 s and 0.22 s,respectively.These results demonstrate the effectiveness of the azimuth cutoff compensation method.Based on the azimuth cutoff compensation method,the multisatellite SAR networking mode for wave observations are discussed.The highest compensation effect is obtained when the combination of azimuth angle is(95°,115°,135°),the orbital intersection angle is(50°,50°),and three or four satellites are used.The study of the multisatellite networking mode in this paper can provide valuable references for the compensation of azimuth cutoff and the observation of waves by a multisatellite network.

核磁共振测井T_(2cutoff)确定方法及适用性分析

T2cutoff是核磁共振测井中的一个重要参数,它决定了核磁共振测井测量的有效孔隙度、渗透率、自由流体饱和度、束缚水饱和度等参数的精确程度.目前国内外普遍选取的T2cutoff为:砂泥岩储层取33ms,碳酸盐岩储层取92ms.实际研究发现T2cutoff应是变化的量而并非单一值.简单的运用单一的T2cutoff来计算各种地层参数势必会产生误差甚至得出错误的解释结论.叙述了33ms作为T2cutoff的由来及其不合理性,同时分析了目前国内外确定T2cutoff的各种方法及其适用性.

Analysis of petrophysical cutoffs of reservoir intervals with production capacity and with accumulation capacity in clastic reservoirs

Methodologies have been developed for calculating cutoffs of reservoir intervals with production capacity （RIPC） and reservoir intervals with accumulation capacity （RIAC） according to the types of pore throat structures and dynamic force by using data from petrophysical analysis, production tests and mercury injection. The data are from clastic reservoirs in the third member （Es3） and the fourth member （Es4） of the Shahejie Formation in the Shengtuo area on the North Slope of the Dongying Sag, Jiyang Depression, China. The method of calculating cutoffs of RIPC is summarized as follows： 1） determination of permeability cutoffs of RIPC; 2） classification of types of pore-throat structures according to mercury injection data and then relating porosity to permeability and determining the relationship between porosity and permeability according to each type of pore-throat structure; and 3） calculating porosity cutoffs of RIPC using established correlation between porosity and permeability according to the type of pore throat structure. The method of calculating cutoffs of RIAC includes： 1） establishing a functional relationship between oil-water interracial tension and formation temperature; 2） calculating limiting values of maximum connected pore-throat radii according to formation temperature and dynamic forces of each reservoir interval; 3） correlating permeability with maximum connected pore-throat radius and then obtaining permeability cutoffs of RIAC; and 4） calculating porosity cutoffs on the basis of permeability cutoffs according to specific correlations, suitable for the type of porethroat structure. The results of this study show that porosity and permeability cutoffs of clastic reservoirs decrease with depth. For a fixed permeability cutoff, the porosity cutoff of R1PC varies because the type of pore throat is different. At a fixed temperature, porosity and permeability cutoffs of RIAC decrease as dynamic force increases. For a fixed permeability cutoff of effective hydrocarbon accumulation, the porosity cutoff also varies with different types of pore throat.

应用定值血清控制HBsAg检测中Cutoff值

采用ELISA方法测定HBsAg,判定HBsAg阴、阳性的标准是Cutoff值,然而ELISA方法受操作、仪器、试剂、环境、温度等多种条件因素影响,同一被测物每次测得的OD值会产生变异,用不同批号的试剂测定同一被测物,测得的OD值也存在显著性差异,如果Cutoff值始终定为0.105来判定结果是不准确的,因此每次实验的Cutoff值应该由一种标准品对其进行校正。本次实验也证明了在一定浓度范围内,HBsAg的浓度与测得的OD值成正比,因此每一次实验可采用定值血清来校正Cutoff值,使被测物的测定结果更加合理和准确。材料与方法1．标本:4ng、2ng HBsAg定值血清,卫生部临检中心生产。2．仪器:法国paster酶标仪(LP40)

单生过程separationcutoff的基于特征值的判别准则

对于时间逆具有随机单调性的以{0,1,…,mn}({mn}为关于n单调增的自然数列)为状态空间且从0出发的单生过程族,利用其负转移速率矩阵第一非零特征值的正性及最快强平稳时的任意阶矩,可以由转移速率矩阵的特征值表示这些性质,得到该族马氏过程separation cutoff存在的一个基于特征值的判别准则,验证了Peres的乘积条件对于此类单生过程成立.

LY12CZ、LC4CS铝合金、30CrMnSiA钢在不同介质下的DFR_(cutoff)值

对LY12CZ、LC4CS铝合金和30CrMnSiA钢进行了不同环境介质下的“细节疲劳额定强度截止值(DFR_(cutoff))”的试验研究,提供了飞机结构耐久性设计的重要数据。研究表明,不同环境介质对不同材料的寿命影响不同,轻重程度依次是:室温空气,潮湿空气,3.5％NaCl盐水。

血浆同型半胱氨酸的CutOff值及其临床意义探讨

同型半胱氨酸(homocysteine,Hcy)不但是脑卒中发生的独立危险因子,而且与高血压有协同作用,被《中国高血压防治指南(2010版)》确定为心血管八大危险因素之一。脑卒中是我国居民第一位死因,由于遗传和生活习惯的差异,中国人群的Hcy水平显著高于西方国家,因此在我国强调控制高血压的同时,加强控制高Hcy水平等其他脑卒中高发危险因素意义更加重大。国内外大量研究证明,在叶酸缺乏或者没有强化叶酸的地区,Hcy水平高于10μmol/L的人群脑卒中发生率显著增加,尤其是对于同时伴有高血压的患者而言;补充叶酸以降低Hcy水平能够显著降低脑卒中发生风险。此外,没有资料表明Hcy在人体内具有重要生理功能,关于补充叶酸以预防心脑血管事件发生的研究在Hcy水平较低的受试人群也仍然显示了有益的效果,而且补充小剂量叶酸以降低血浆Hcy水平(即使在<10μmol/L的情况下)在降低脑卒中发生风险的同时并不增加其他任何健康风险。《中国高血压防治指南》制定的高Hcy Cut Off值(>10μmol/L)可作为我国医务工作者规范开展脑卒中预防工作的参考,在临床实践中,提高Hcy的Cut Off值(如>12μmol/L或>15μmol/L)等将使大量潜在脑卒中高发人群得不到及时关注和干预,增加脑卒中发生风险,尤其是在高血压患者群中。因此在中国高血压患者群中较好地控制血浆Hcy水平对于开展我国脑卒中防治工作有着重要意义。

ABO血型自动微板法Cutoff值建立研究

目的 探讨研究一种简便、可靠的ABO血型自动微板法Cutoff值建立方法。方法 用ABO血型自动微板法测定3％(v/v)O型和AB型红细胞盐水悬液与抗A、抗B血清在微孔板中吸光度A值并行正态性D检验,判断A值是否服从正态性分布,再据正态分布法制订ABO血型自动微板法抗A与抗B血清侧Cutoff值。结果 测定得出吸光度A值服从正态分布原则,可应用数理统计求出ABO血型自动微板法的Cutoff值。结论 根据正态分布原则可简便、科学地计算出ABO血型自动微板法Cutoff值,一次判读准确率达到98.85％。

Dynamical and Chemical Features of a Cutoff Low over Northeast China in July 2007:Results from Satellite Measurements and Reanalysis

The European Centre for Medium-Range Weather orology and measurements from the Microwave Limb Forecasts Re-Analysis Interim （ERA-Interim） meteSounder, High Resolution Dynamics Limb Sounder, and Ozone Monitoring Instrument onboard the Earth Observing System Aura satellite were applied to analyze the dynamical and chemical features of a cutoff low （COL） event over northeast China in early July 2007. The results showed the polar stratospheric origin of an upper-level warm-core cyclone at 100 300 hPa, associated with a funnel-shaped tropopause intruding into the mid-troposphere just above the COL center. The impacts of the stratospheric intrusion on both column ozone and ozone profiles were investigated using satellite measurements. When the intensity of the COL peaked on 10 July 2007, the total column ozone （TCO） increase reached a maximum （40-70 DU）. This could be dynamically attributed to both the descent of the tropopause （~75%） and the downward transport of stratospheric ozone across the tropopause （~25%）. Analysis of the tropospheric ozone profiles provided evidence for irreversible transport/mixing of ozone-rich stratospheric air across the tropopause near the upper-level front region ahead of the COL center. This ozone intrusion underwent downstream transport by the upper tropospheric winds, leading to further increase in TCO by 12 16 DU over broad regions extending from east China toward the northern Japan Sea via South Korea. Meteorological analysis also showed the precedence of the stratospheric intrusion ahead of the development of cyclones in the middle and lower troposphere.

Growth and characteristics of InAsSb epilayers with a cutoff wavelength of 4.8 μm prepared by one-step liquid phase epitaxy

InAsSb epilayers with a cutoff wavelength of 4.8 μm have been successfully grown on InAs substrates by one-step liquid phase epitaxy （LPE） technology. The epilayers were characterized by X-ray diffraction （XRD）, Fourier transform infrared （PTIR） transmittance measurements and scanning electron microscopy （SEM）. The influence of different growth conditions on the optical and structural properties of the materials was studied. The results revealed that the good crystalline quality, mirror smooth surface and flat interface of InAsSb epilayers were achieved. They benefited from optimized growth conditions, i.e., sufficient homogeneity of the growth melt and a very slow cooling rate.

Impact of an artificial chute cutoff on the river morphology and flow structure in Sipaikou area of the Upper Yellow River

Artificial chute cutoff can fundamentally eliminate the threat of flood caused by the meandering river,but it significantly changes its morphodynamic characteristics.Channel adjustments after cutoff are rapid,which makes it difficult to study the interaction between river morphology and flow structure only through field measurement.However,numerical simulations can provide insights into the hydrodynamic characteristics after artificial chute cutoffs.In this study,both field measurement and numerical simulation are employed to investigate the flow structure and bed morphology caused by an artificial chute cutoff in Sipaikou area of the Upper Yellow River in 2018.The measured hydrological data provide boundary conditions and initial values for the numerical model.The field measurement results reveal that the concave bank of the study area is severely scoured up to 270 m after the artificial cutoff,and a 20 m deep scour hole and a 2.26 km long pool are formed at the entrance and near the left bank of the chute channel.The numerical simulation results of velocity at typical cross-sections are in good agreement with the measurement results.Flow separation and stagnation zones are observed near the right bank during the low flow conditions(discharge of at least 902 m^(3)/s),but this phenomenon is not seen during larger flow conditions(discharge exceeds 2000 m^(3)/s).Interestingly,flow recirculation zones are also found near the left and right banks of the scour hole.Further,a long flux belt is formed at the scour hole and the pool.Consequently,the impact of the bed topography on the hydrodynamic characteristics is relatively prominent when the discharge is small,while the impact on the river banks and river bed is more noticeable when the water discharge is large.In addition,high shear stress is observed near the left bank at the downstream of the studied area,which indicates that the left bank at the downstream is still being scoured.These results suggest that bank protection measures along the left bank are required to maintain the effectiveness of the artificial chute cutoff.

Modulation of the cutoff wavelength in the spectra for solar selective absorbing coating based on high-entropy films

This paper demonstrates an intrinsic modulation of the cutoff wavelength in the spectra for solar selective absorbing coating based on high-entropy films.The(NiCuCrFeSi)N((NCCFS)N)films were deposited by a magnetron sputtering system.Rutherford backscattering spectroscopy analysis confirms the uniform composition and good homogeneity of these high-entropy films.The real and imaginary parts of the permittivity for the(NCCFS)N material are calculated on the basis of the reflectance spectral fitting results.A redshift cutoff wavelength of the reflectance spectrum with increasing nitrogen gas flow rate exists because of the different levels of dispersion when changing nitrogen content.To realize significant solar absorption,the film surface was reconstituted to match its impedance with air by designing a pyramid nanostructure metasurface.Compared with the absorptance of the as-deposited films,the designed metasurface obtains a significant improvement in solar absorption with the absorptance increasing from 0.74 to 0.99.The metasurfaces also show low mid-infrared emissions with thermal emittance that can be as low as 0.06.These results demonstrate a new idea in the design of solar selective absorbing surface with controllable absorptance and low infrared emission for high-efficiency photo-thermal conversion.

Significant wave height estimation using azimuth cutoff of C-band RADARSAT-2 single-polarization SAR images

This paper proposes two simple models, look-up table（LUT） model and empirical model, to directly retrieve significant wave height（Hs） using synthetic aperture radar（SAR） azimuth cutoff（λc）. Both models aim at C-band VV, HH, VH, and HV single-polarization SAR images. The LUT model relates Hs to λc, while the empirical model relates Hs to both λc and SAR range-to-velocity（β）. The LUT model coefficients are derived by simulation under different sea states and observation conditions, which depend on incidence angle（θ）, wave direction（dw）, and βbut are independent of polarization. The empirical model coefficients are obtained by fitting the collocated data,which only depend on polarization. To fit empirical model coefficients and validate the two models, C-band RADARSAT-2 fine quad-polarization（VV＋HH＋VH＋HV） single-look complex（SLC） SAR images and collocated buoy data are collected. Retrieved Hs, using Yang model and the two models proposed in this paper from four kinds of polarization SAR data, are compared with buoy Hs. Results show that both LUT and empirical models have the capacity of retrieving Hs from C-band RADARSAT-2 co-polarization SAR data, while Yang model is not suitable for these kinds of SAR data. Moreover, the empirical model is also valid for cross-polarization SAR data showing clear ocean wave stripes.

Extension of high-order harmonic cutoff frequency by synthesizing the waveform of a laser field via the optimization of classical electron trajectory in the laser field

We theoretically investigate high-order harmonic generation by employing strong-field approximation （SFA） and present a new approach to the extension of the high-order harmonic cutoff frequency via an exploration of the dependence of high-order harmonic generation on the waveform of laser fields. The dependence is investigated via detailed analysis of the classical trajectories of the ionized electron moving in the continuum in the velocity-position plane. The classical trajectory consists of three sections （Acceleration Away, Deceleration Away, and Acceleration Back）, and their relationship with the electron recollision energy is investigated. The analysis of classical trajectories indicates that, besides the final （Acceleration Back） section, the electron recollision energy also relies on the previous two sections. We simultaneously optimize the waveform in all three sections to increase the electron recollision energy, and an extension of the cutoff frequency up to Ip ＋ 20.26Up is presented with a theoretically synthesized waveform of the laser field.

THE NON-CUTOFF BOLTZMANN EQUATION WITH POTENTIAL FORCE IN THE WHOLE SPACE

This paper is concerned with the non-cutoff Boltzmann equation for full-range interactions with potential force in the whole space. We establish the global existence and optimal temporal convergence rates of classical solutions to the Cauchy problem when initial data is a small perturbation of the stationary solution. The analysis is based on the time-weighted energy method building also upon the recent studies of the non-cutoff Boltzmann equation in [1-3, 15] and the non-cutoff Vlasov-Poisson-Boltzmann system [6].

Screening for depressive symptoms among older adults in Taiwan: Cutoff of a short form of the Center for Epidemiologic Studies Depression Scale

Screening for elders at risk for depression is crucial for promoting mental health in later life. The present study investigates the cutoff score of a short form of the CES-D for screening of depressive symptoms in the elderly population of Taiwan. This particular short form of CES-D is repeatedly used in the Taiwan Longitudinal Study on Aging (TLSA), a national survey of representative older adults in Taiwan, and is therefore referred to as the TLSA form. Data collected from five waves of TLSA were analyzed in this study. Participant responses repeatedly measured in 1989 and 1993 were used to identify a cutoff for the TLSA form of the CES-D with sensitivity and specificity using the cutoff of 4 on the Boston form of the CES-D as the criterion. Longitudinal data from the years 1996, 1999, and 2003 were used to validate the proposed cutoff by comparing the prevalence rates for depressive symptoms among older Taiwan Residents estimated from the identified cutoff and reported in previous studies. The score of 10 on the TLSA form of the CES-D was suggested, yielding a specificity of 0.93 and a sensitivity of approximately 0.96. The estimated prevalence rates for depressive symptoms among Taiwan Residents elders based on the suggested cutoff were between 18.9% and 23.7%, which are similar to previously reported rates. The cutoff score of 10 on the TLSA form of the CES-D is therefore recommended for screening depressive symptoms among older adults in Taiwan.

Waist circumference cutoff points for Chinese adults with metabolic syndrome defined by the International Diabetes Federation

Objective To investigate the appropriate waist circumference (WC) cutoff points for central obesity in the middle-aged and elderly Beijing residents by the metabolic syndrome definition of the International Diabetes Federation (IDF). Methods A total of 2,344 Beijing residents aged ≥40 years were investigated. They answered questionnaires, received physical examinations, and underwent plasma glucose and lipid profile measurement. Those non-diabetic subjects underwent a 75g oral glucose tolerance test. All data were analyzed to calculate the appropriate WC cutoff points for central obesity reaching the diagonsis of MS. Results 1) Both in males and females, the triglyceride (TG), systolic blood pressure, diastolic blood pressure and fasting plasma glucose (FPG) increased linearly with WC, and the high density lipoprotein cholesterol (HDL-C) decreased linearly with WC (P<0.05). 2)The prevalence of elevated TG, reduced HDL-C, elevated blood pressure, elevated FBG, or ≥ 2 of these factors increased with WC (P<0.05). 3) Based on the receiver operating characteristic (ROC) curve analysis and Youden index, the WC values for central obesity and for detecting BMI ≥ 25 kg/m2 were about 90 cm for men and 80 cm for women. 4) The odds ratio for the presence of two or more metabolic risk factors increased abruptly in men with WC ≥ 90 cm and in women with WC ≥ 80 cm. Conclusions The appropriate WC cutoff point for central obesity was determined to be 90 cm for men and 80 cm for women in the middle-aged and elderly Beijing residents by the metabolic syndrome definition of IDF.

VARIABLE CUTOFFF REQUENCY NONLINEAR DIGITAL FILTER: II-TWO-DIMENSION

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VARIABLE CUTOFF FREQUENCY NONLINEAR DIGITAL FILTERS: I-ONE-DIMENSION

ＶＡＲＩＡＢＬＥＣＵＴＯＦＦＦＲＥＱＵＥＮＣＹＮＯＮＬＩＮＥＡＲＤＩＧＩＴＡＬＦＩＬＴＥＲＳ：Ｉ－ＯＮＥ┐ＤＩＭＥＮＳＩＯＮ＊ＧｕＨｏｎｇ（古红）ＺｈｕＹｉｓｈｅｎｇ（朱贻盛）（ＩｎｓｔｉｔｕｔｅｏｆＢｉｏｍｅｄｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ，Ｓｈａ...