基于树莓派的物联网开放平台

针对当前物联网所面对的共性需求,提出了建立开放性的物联网服务平台,为物联网世界提供开放的服务。完成了对传感器数据的接入、管理、存储、处理及应用。并以树莓派作为网关设备端进行图像数据的采集,通过Http或Socket.IO与云平台服务器建立连接,完成数据的实时传输。     

Bottom‐Up Grown 2D InSb Nanostructures

Low‐dimensional high‐quality InSb materials are promising candidates for next‐generation quantum devices due to the high carrier mobility, low effective mass, and large g‐factor of the heavy element compound InSb. Various quantum phenomena are demonstrated in InSb 2D electron gases and nanowires. A combination of the best features of these two systems (pristine nanoscale and flexible design) is desirable to realize, e.g., the multiterminal topological Josephson device. Here, controlled growth of 2D nanostructures, nanoflakes, on an InSb platform is demonstrated. An assembly of nanoflakes with various dimensions and morphologies, thinner than the Bohr radius of InSb, are fabricated. Importantly, the growth of either nanowires or nanoflakes can be enforced experimentally by setting growth and substrate design parameters properly. Hall bar measurements on the nanostructures yield mobilities up to ≈20 000 cm² V^?1 s^?1 and detect quantum Hall plateaus. This allows to see the system as a viable nanoscale 2D platform for future quantum devices.     

Theoretical analysis of the impact of Rayleigh noise on the performance of distributed Raman temperature sensors

We present a theoretical model to analyze the impact of Rayleigh noise on Raman distributed temperature sensors (RDTS), which use the anti-Stokes and Stokes light or anti-Stokes component only as the demodulation signals. Based on this model, the effects of Rayleigh noise on temperature accuracy, sensitivity, and resolution are investigated both at only one point and in a section of the fiber. The analysis indicates that for RDTS demodulated by anti-Stokes light only, the temperature accuracy, sensitivity, and resolution decrease by about 1°C, 10%, and 0.25°C on the assumption that the Rayleigh noise accounts for 10% of the anti-Stokes intensity. Moreover, for RDTS demodulated by Stokes and anti-Stokes light, the temperature accuracy, sensitivity, and resolution decrease by about 1°C, 10%, and 0.2°C assuming that the Rayleigh noise in two paths is equal to 10% of the intensity of anti-Stokes and Stokes light. The analysis demonstrates that the impact of Rayleigh noise on sensing capacities of RDTS is non-negligible, thus providing a major contribution to the elimination of Rayleigh noise in RDTS.     

Speckle noise in bar-code scanning systems--power spectral density and SNR

Laser-based flying-spot scanners are strongly affected by speckle that is intrinsic to coherent illumination of diffusing targets. In such systems information is usually extracted by processing the derivative of a photodetector signal that results from collecting over the detector's aperture the scattered light of a laser beam scanning a bar code. Because the scattered light exhibits a time-varying speckle pattern, the signal is corrupted by speckle noise. In this paper we investigate the power spectral density and total noise power of such signals. We also analyze the influence of speckle noise on edge detection and derive estimates for a signal-to-noise ratio when a laser beam scans different sequences of edges. The theory is illustrated by applying the results to Gaussian scanning beams for which we derive closed form expressions.     

蓄冷板冻结与释冷的实验研究

通过实验的方式,分别研究了初始温度为30℃的Na Cl蓄冷板在-25、-35和-40℃的环境中的冻结过程以及初温度为-25℃的Na Cl蓄冷板在-10、-5和0℃环境中的释冷过程。实验结果表明:在冻结过程中,当环境温度低于Na Cl共晶液的共晶温度-21.2℃时,环境温度对共晶液开始结晶的时间有较大影响,而对共晶液从开始结晶至完全冻结过程所需时间影响较小;释冷过程中,环境温度高于Na Cl共晶液共晶温度-21.2℃时,外界环境对蓄冷板释冷所需时间以及共晶冰开始融化到完全融化的过程影响较大。     

Diabetes Prediction Algorithm Using Recursive Ridge Regression L2

At present, the prevalence of diabetes is increasing because the human body cannot metabolize the glucose level. Accurate prediction of diabetes patients is an important research area. Many researchers have proposed techniques to predict this disease through data mining and machine learning methods. In prediction, feature selection is a key concept in preprocessing. Thus, the features that are relevant to the disease are used for prediction. This condition improves the prediction accuracy. Selecting the right features in the whole feature set is a complicated process, and many researchers are concentrating on it to produce a predictive model with high accuracy. In this work, a wrapper-based feature selection method called recursive feature elimination is combined with ridge regression (L2) to form a hybrid L2 regulated feature selection algorithm for overcoming the overfitting problem of data set. Overfitting is a major problem in feature selection, where the new data are unfit to the model because the training data are small. Ridge regression is mainly used to overcome the overfitting problem. The features are selected by using the proposed feature selection method, and random forest classifier is used to classify the data on the basis of the selected features. This work uses the Pima Indians Diabetes data set, and the evaluated results are compared with the existing algorithms to prove the accuracy of the proposed algorithm. The accuracy of the proposed algorithm in predicting diabetes is 100%, and its area under the curve is 97%. The proposed algorithm outperforms existing algorithms.     

舞钢连铸辊堆焊设备的改造实践

连铸辊在连铸生产中会产生表面裂纹、磨损、弯曲、剥离掉肉等缺陷,严重时不但影响其使用寿命,还直接影响到钢坯质量。采用堆焊方法既可以消除这些缺陷,同时还能取得修旧利废和提高钢坯质量的双重目的。舞钢充分利用报废CDZ6140车床和闲置ZD5-1250自动埋弧焊机,将其改造成连铸辊埋弧自动堆焊的专用设备。缺陷连铸辊经过堆焊、加工和修磨,完全满足连铸生产的工艺要求,达到了新连铸辊的质量和使用寿命。     

Juvenile gigantomastia: report of a case

This commentary focuses on the current workings of Medicare's Volume Performance Standards and possible alternatives that would make the program more effective in containing costs. The author presents his own perspectives as well as examining the options put forward in the two related papers by Holahan and Auckerman and Miller and Welch published in this issue of Inquiry.     

Transmutation by adiabatic resonance crossing experiment (TARC) benchmarking

In present study the benchmarking of TARC experiment was done. MCNPX code with JENDL-HE, JENDL-4, JENDL-3.3 and LA-150 nuclear data libraries were used for simulations. The calculated neutron fluences, energy-time correlations of resonance reactions and transmutation rates of ⁹⁹Tc and ^127,129I were compared with experimental measurements. On the base of comparative analysis of simulations the validation of nuclear data libraries was performed and recommendations were given, as follows:

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the JENDL-4 library contains better neutron elastic cross-section data for natural lead in energy range from ∼0.01 eV to ∼100 eV comparing to other considered data libraries;     

Protein profiles and total antioxidant capacity of water‐soluble and water‐insoluble fractions of white brined goat cheese at different stages of ripening

This study deals with proteolysis and total antioxidant capacity of proteins of white brined cheese prepared from overheated goat milk and ripened for fifty days. Proteolytic changes were reflected through the relatively low level of soluble nitrogen (50 days ripened cheese had 15.32 g/100 g of water‐soluble nitrogen, 8.1 g/100 g of TCA‐soluble nitrogen and 2.69 g/100 g of PTA‐SN), intensive proteolysis of α_s2‐CN during initial 10 days of ripening (up to 50.70% of initial content) and its much slower degradation through further 40 days, slow but continual decrease of β‐CN content (up to 85.14% of residual content) and high level of proteolytic products tightly bounded into gel network. Total antioxidant capacity of water‐soluble and water‐insoluble fractions increased after cheese ripening. These findings could be useful for better understanding and control over the production of white brined goat cheese as highly valuable functional product.