利用电场与磁场耦合制备微型化频率选择表面

利用感性表面(金属栅格)与容性表面(间隔的金属环形贴片)之间的耦合机制制备了微型频率选择表面(MEF-SS)。依据传输线理论给出电感、电容近似公式,定性分析了MEFSS结构参数,采用全波分析矢量模匹配法计算了不同几何结构参数与耦合层电参数MEFSS的传输特性。通过镀膜与光刻法在500μm厚聚酰亚胺膜两侧以矩形排列方式制备了12个0.125λ集总电感单元与集总电容单元,利用自由空间法测试了240mm×240mm MEFSS样件的传输特性。结果显示,测试样件中心频点为14.636GHz,透过率为-0.382dB,-3dB,带宽为2.17GHz时,单元尺寸为0.125λ;当单元尺寸变小时,中心频点向高频漂移,其透过率下降;固定单元尺寸,中心频点随固定电感宽度、电容间隔和环形贴片宽度的增加而向高频漂移;耦合层厚度增加0.4mm,中心频点向低频漂移1.4GHz,且透过率降低2.6dB;相对介电常数由3.5变为2,中心频点向高漂移2.8GHz。结论显示,利用感性与容性表面耦合机制能制备单元尺寸为0.125λ的FSS,其具有微型化、宽通带和对入射波角度不敏感的特点。

基于LC耦合机制调谐设计薄屏宽带频率选择表面

以环形单元为基础设计出一种三屏金属阵列通过两层薄介质级联的频率选择表面(FSS)。建立等效电路模型,根据传输线理论给出金属栅格阵列(感性表面)与间隔的金属方环(容性表面)的近似电容、电感公式,通过调整结构几何参数分析LC耦合机制,调谐出最优的宽带传输特性。最后,采用PCB加工工艺制备了FSS样件并在暗室进行了传输特性测试。得到的测试结果与数值结果一致,结果表明这种频率选择表面对电磁波大角度入射和不同电磁波极化方式都具有稳定的传输特性。

一种Ku波段／毫米波波段独立双通带微型化频率选择表面

为了满足现代通信设备多频带及集成化要求，基于三屏耦合机制和双屏谐振机制，设计了一种在Ku波段和毫米波波段具有独立双通带、微型化和“矩形化”滤波特性的频率选择表面（FSS）.根据物理结构分析了其作用机理，并采用矢量模式匹配法计算了其传输特性.结果表明：该结构单元尺寸仅为第一通带谐振波长的0.104倍，具有微型化特征；第二通带在42.6 GHz和49.6 GHz时出现双峰，在47.4 GHz时出现-0.828 dB的“浅谷”，具有“矩形化”传输特性；两个通带间隔约30 GHz且相互独立，在0°~60°扫描范围内均具有良好的角度稳定性.这种多功能的FSS可以满足工程应用要求.

一种实现微型频率选择表面通带开关的方法

微型频率选择表面(MEFSS)基于感性表面(金属栅格)与容性表面(间隔的金属环形贴片)之间的耦合机制实现带通滤波功能。采用全波分析矢量模匹配法精确计算了耦合介质的相对介电常数εr、厚度d对MEFSS传输特性的影响:εr由3.5变为2时中心频点高漂2.8GHz,d增加0.4mm时中心频点往低频漂移1.4GHz且透过率降低2.6dB。由此可见,通过控制耦合介质厚度能够实现MEFSS通带开关的功能:当耦合介质厚度增加1mm时通带中心频点透过率降低8.173dB。在覆铜的聚酰亚胺膜上复制光刻制备感性表面、容性表面并分别置于0.2mm、1.2mm厚泡沫板两侧采用自由空间法测试了其传输特性。计算与实验结果均表明:通过控制耦合介质厚度变化能够实现MEFSS通带开关的功能,为实现有源FSS提供一种新的方向。

基于十字单元的可调谐互补屏频率选择表面

为实现频率选择表面(FSS)工作频点的可调谐,将环型孔径FSS负载分离后形成感性表面与容性表面,利用两者之间的耦合机制设计了一种互补屏FSS。建立了互补屏FSS等效电路模型,定性分析了它的变频机理。采用耦合积分方程法计算了负载贴片旋转角,耦合电介质厚度和相对介电常数对互补屏传输特性的影响。利用镀膜与光刻方法在耦合电介质两侧制备容性表面与感性表面,并用自由空间法测试250mm×250mm样件的传输特性。计算与测试结果均表明:当十字贴片从0°旋转至10°,互补屏FSS的谐振频点会从18.2GHz向低频漂移至14.8GHz。当耦合电介质的物理厚度从0.1mm变化到1mm时,互补屏FSS的容性表面和感性表面之间的耦合效应逐渐消失。耦合电介质相对介电常数增加使互补屏间的耦合增强,其工作频点向低频漂移。实验显示:随着负载贴片旋转角的变化,互补屏FSS能够实现主动变频功能,为设计和制备主动FSS提供借鉴。

一种双屏FSS的小型化设计

基于容性表面和感性表面的耦合机理,在ku波段提出了一种新型的微型频率选择表面(MEFSS)的设计。该单元延续了MEFSS良好的特性,克服了传统谐振单元在低频段,单元尺寸过长,单元间介质层过厚的缺点。使周期单元尺寸不受中心谐振波长的限制。在0.15mm薄的介质两侧分别贴合圆环单元构成的电容和十字金属栅格构成的电感构成MEFSS,利用全波分析软件对本单元进行全波仿真。并且,通过研究不同的几何参数,总结了传输特性规律。仿真结果显示该设计单元在ku波段-3 d B带宽达到5.29GHz,单元尺寸减小为0.11?,中心频点在14.8 GHz,具有微型化、超宽带,角度稳定性和极化稳定性好的特点。

Affinity and fluorescent detection of surfactants/ssDNA and single-walled carbon nanotube

A new biosensor platform was explored for detection of surfactant based on fluorescence changes from single strand DNA （ssDNA） and single-walled carbon nanotubes （SWNTs）. Thermodynamics assay was performed to value the stability of probe. The affinities of SWNT to five common surfactants （SDS, DBS, Triton X-100, Tween-20 and Tween-80） were investigated by real-time fluorescence method. The effects of Mg^2＋ and pH on the fluorescence intensity of self-assembled quenched sensor were performed. The fluorescent emission spectra were used to measure the responses of self-assembled quenched fluorescent of ssDNA/SWNTs to different concentration surfactant（Triton X-100）. The FAM-DNA wrapped SWNTs probe was stable in a wide temperature range （5 ℃ to 80℃）. The binding strength of surfactants and single-stranded DNA （ssDNA） on SWNTs surfaces was shown as follows： Triton X-100〉DBS〉Tween-20〉Tween-80〉ssDNA〉SDS, and the optimized reaction conditions included pH 7.4 and 10 mmol/L Mg2＋. The fluorescence of FAM-ssDNA wrapped SWNTs was proportionally recovered as a result of adding different concentrations of Triton X- 100, which realizes the quantitative detection of Triton X- 100.

Association of chronic viral hepatitis B with insulin resistance

AIM:To investigate the relationship between chronic viral hepatitis B(CVHB) and insulin resistance(IR) in Korean adults.METHODS:A total of 7880 adults(3851 men,4029 women) who underwent a comprehensive medical examination were enrolled in this study.Subjects diagnosed with either diabetes mellitus,or any other disorder that could influence their insulin sensitivity,were rejected.Anthropometry,metabolic risk factors,hepatitis B surface antigen,hepatitis B surface antibody,hepatitis B core antibody,fasting plasma glucose and insulin were measured for all subjects.Homeostasis model assessment(HOMA),quantitative insulin check index(QUICKI),and Mf fm index were used for determining insulin sensitivity.Each participant was categorized into a negative,recovery,or CVHB group.To compare variables between groups,a t-test and/or one-way analysis of variance were used.Partial correlation coefficients were computed to present the association between insulin resistance and other variables.Multiple logistic regression analysis was used to assess the independent association between CVHB and IR.RESULTS:The mean age of men and women were 48.9 and 48.6 years,respectively.Subjects in the CVHB group had significantly higher waist circumference [(86.0 ± 7.7 cm vs 87.3 ± 7.8 cm,P = 0.004 in men),(78.3 ± 8.6 cm vs 80.5 ± 8.5 cm,P < 0.001 in women)],cystatin C [(0.96 ± 0.15 mg/dL vs 1.02 ± 0.22 mg/dL,P < 0.001 in men),(0.84 ± 0.15 mg/dL vs 0.90 ± 0.16 mg/dL,P < 0.001 in women)],fasting insulin [(5.47 ± 3.38 U/mL vs 6.12 ± 4.62 U/mL,P < 0.001 in men),(4.57 ± 2.82 U/mL vs 5.06 ± 3.10 U/mL,P < 0.001 in women)] and HOMA index [(1.24 ± 0.86 vs 1.43 ± 1.24,P < 0.001 in men),(1.02 ± 0.76 vs 1.13 ± 0.87,P = 0.033 in women)] compared to control group.The HOMA index revealed a positive correlation with body mass index(BMI)(r = 0.378,P < 0.001),waist circumference(r =0.356,P < 0.001),percent body fat(r = 0.296,P < 0.001),systolic blood pressure(r = 0.202,P < 0.001),total cholesterol(r = 0.134,P < 0.001),triglycerides(r = 0.292,P < 0.001),cystatin C(r = 0.069,P < 0.001) and uric acid(r = 0.142,P < 0.001).The QUICKI index revealed a negative correlation with BMI(r =-0.254,P < 0.001),waist circumference(r = 0-0.243,P < 0.001),percent body fat(r =-0.217,P < 0.001),systolic blood pressure(r =-0.132,P < 0.001),total cholesterol(r =-0.106,P < 0.001),triglycerides(r =-0.205,P < 0.001),cystatin C(r =-0.044,P < 0.001) and uric acid(r =-0.096,P < 0.001).For subjects identified with IR,the odds ratio of an accompanying diagnosis of chronic hepatitis B was 1.534(95% CI:1.158-2.031,HOMA index criteria) or 1.566(95% CI:1.124-2.182,QUICKI criteria) after adjustment for age,gender,BMI,and amount of alcohol consumption.CONCLUSION:Our study demonstrates that CVHB is associated with IR.CVHB may need to be monitored for occurrence of IR and diabetes mellitus.

Flood Hazard Prediction from Soil Properties by Remote Sensing and Genographic Information System:A Case Study of Mae Rim Watershed,Chiang Mai Province,Thailand

Physiography and soil in Mae Rim watershed, Chiang Mai Province, Thailand were investigated by using aerial photographs and satellite image in conjunction with field work, and soil infiltration rate and soil shear resistance were measured in field. Many factors affecting runoff were analyzed using the Integrated Land and Water Information System (ILWIS). As a result, a model determining flood hazard was set up. Three maps including runoff curve number map, runoff coefficient map, and flood inundation map were created. In addition, the time of concentration was predicted.

Impact of Sea Surface Temperature on COSMO Forecasts of a Medicane over the Western Mediterranean Sea

The paper describes and analyzes the sensitivity of an operational atmospheric model to different SST （sea surface temperature） estimates. The model＇s sensitivity has been analyzed in a Medicane （Mediterranean hurricane） test case. Numerical simulations have been performed using the COSMO （consortium for small-scale modeling） atmospheric model, in the COSMO-ME configuration. The model results show that the model is capable of capturing the position, timing and intensity of the cyclone. Sensitivity experiments have been carried out using different SSTs surface boundary conditions for the COSMO forecasts. Four different experiments have been carried out： the first two using SST fields obtained from the OSTIA （operational sea surface temperature and sea ice analysis） system, while the other two using the SST analyses and forecasts from MFS （Mediterranean Forecasting System, Tonani et al., 2015; Pinardi and Coppini, 2010）. The different boundary conditions determine differences in the trajectory, pressure minimum and wind intensity of the simulated Medicane. The sensitivity experiments showed that a colder than real SST field determines a weakening of the minimum pressure at the vortex center. MFS SST analyses and forecasts allow the COSMO model to simulate more realistic minimum pressure values, trajectories and wind speeds. It was found that MFS SST forecast, as surface boundary conditions for COSMO-ME runs, determines a significant improvement, compared to ASCAT observations, in terms of wind intensity forecast as well as cyclone dimension and location.

微型化频率选择表面的设计研究

利用容性表面与感性表面之间的耦合机理能够制备微型化频率选择表面(MEFSS),周期单元尺寸将不受工作波长限制.为了提高MEFSS角度与极化的稳定性,展宽MEFSS的-3dB带宽,文章结合传统频率选择表面"Y"形单元,利用"Y"图形构造容性表面的贴片单元与感性表面的网栅单元且以正三角形栅格拓展周期单元,采用矢量模匹配法对MEFSS栅格排布及其他结构参数变化进行精确计算.通过镀膜与光刻技术在0.15mm厚聚酰亚胺膜两侧制备容性表面、感性表面并利用自由空间法测试.计算与实验结果均表明,采用正三角形栅格排布的MEFSS,-3dB带宽达到7.6GHz,不同极化下60°扫描时中心频点稳定在f0,为MEFSS应用于曲面天线罩时提供理论与实验参考依据.

Skin Sensitive Difference of Human Body Sections under Clothing — Comparative Judging of Body Sections' Cold Sensitivity Sequence

Skin seasitive difference of human body sections under clothing is the theoretic foundation of thermal insulation clothing design. By a new psychological ＆ physical researching method, the subjective psychological perception of human body sections affected by the same cold stimulus are studied, and with Thurstone comparative judgement the main human body sections＇ cold sensitivity sequences are obtained. Furthermore the physiological causes for skin sensitive difference of human body sections under clothing are suggested.

Analyzing Kansei from Facial Expressions by CSRBF Mapping

This paper describes an application where a new KAE （Kansei/Affective Engineering） system was applied to define the properties of the facial images perceived as Iyashi. Iyashi is a Japanese word used to describe a peculiar phenomenon that is mentally soothing, but is yet to be clearly defined. Instead of analyzing facial expressions of an individual to determine his emotional state, the proposed system introduces a FQHNN （fuzzy-quantized holographic neural network） to find the rules involved in the Kansei evaluation provided by the subjects about the limited dataset of 20 facial images. In order to validate and gain a clear insight into the rules involved in the Kansei evaluation process, Procrustes analysis and CSRBFs （compactly-supported radial basis functions） are combined to generate new facial images. Procrustes analysis is used to find the minimal dissimilarity measure between two facial images with opposite classification （i.e., Iyashi and Non-lyashi）. CSRBFs are proposed for tuning of 17 facial parameters and mapping between facial images within opposite classes. The experiments with two subjects demonstrate that if only two from the five most important parameters of the face are changed, then the Kansei evaluation can change to the opposite class. This paper shows that a continuous and efficient tuning of the design space can be achieved by introducing CSRBF mapping into the new KAE system.

Sensitivity studies of a high accuracy surface modeling method

The sensitivities of the initial value and the sampling information to the accuracy of a high accuracy surface modeling(HASM) are investigated and the implementations of this new modeling method are modified and enhanced. Based on the fundamental theorem of surface theory, HASM is developed to correct the error produced in geographical information system and ecological modeling process. However, the earlier version of HASM is theoretically incomplete and its initial value must be produced by other surface modeling methods, such as spline, which limit its promotion. In other words, we must use other interpolators to drive HASM. According to the fundamental theorem of surface theory, we modify HASM, namely HASM.MOD, by adding another important nonlinear equation to make it independent of other methods and, at the same time, have a complete and solid theory foundation. Two mathematic surfaces and monthly mean temperature of 1951–2010 are used to validate the effectiveness of the new method. Experiments show that the modified version of HASM is insensitive to the selection of initial value which is particular important for HASM. We analyze the sensitivities of sampling error and sampling ratio to the simulation accuracy of HASM.MOD. It is found that sampling information plays an important role in the simulation accuracy of HASM.MOD. Another feature of the modified version of HASM is that it is theoretically perfect as it considers the third equation of the surface theory which reflects the local warping of the surface. The modified HASM may be useful with a wide range of spatial interpolation as it would no longer rely on other interpolation methods.

Research on transmission performance of a surface acoustic wave sensing system used in manufacturing environment monitoring

Surface acoustic wave （SAW） sensors show great promise in monitoring fast-rotating or moving machinery in manufacturing environments, and have several advantages in the measurement of temperature, torque, pressure, and strain because of their passive and wireless capability. However, very few studies have systematically attempted to evaluate the characteristics of SAW sensors in a metal environment and rotating structures, both of which are common in machine tools. Simulation of the influence of the metal using CST software and a series of experiments with an SAW temperature sensor in real environments were designed to investigate the factors that affect transmission pertbrmance, including antenna angles, orientations, rotation speeds, and a metallic plate, along with the interrogator antenna-SAW sensor antenna separation distance. Our experimental measure- ments show that the sensor＇s optimal placement in manufacturing environments should take into account all these factors in order to maintain system measurement and data transmission capability. As the first attempt to systematically investigate the transmis- sion characteristics of the SAW sensor used in manufacturing environment, this study aims to guide users of SAW sensor appli- cations and encourage more research in the field of wireless passive SAW sensors in monitoring applications.

Aptamer-based competitive electrochemical assay of small biomolecules

A convenient aptamer-based competitive electrochemical biosensor for a small biomolecule,adenosine,was described. The sensing surface was fabricated by self-assembly of an aptamer/mercaptohexanol monolayer on a gold disk electrode. The principle of this aptasensor is based on the competition between an adenosine target molecule and a ferrocene-conjugated signaling DNA strand for the aptamer binding site on the sensing surface. Due to the competitive nature of this assay,the electrochemical responses of the surface captured ferrocene are inversely proportional to log[adenosine] in the range from 0.05 to 3.2 μM,with a detection limit of 25 nM. Moreover,the aptasensor also shows high selectivity for adenosine. The proposed aptasensor thus holds great potential for the detection of other small biomolecules.

Temperature characteristics of near infrared SPR sen sors with Kretschmann configuration

The temperature characteristics of near infrared surface plasmon resonance （SPR） sensors with Kretschmann configuration are studied theoretically and experimentally. The experimental results match with the numerical simulations in the temperature range from 10 ℃ to 40.℃. With the increase of temperature, the resonance angle for gas increases slightly, but that for aqueous solution decreases obviously. No matter the dielectric layer is gas or aqueous solution, the resonance peaks are both broadened.