金矿掘进副产矿石的定量化管理

通过研究老柞山金矿十几年有关生产技术指标,确定了掘进副产矿石定量化的边界条件,进而结合工业品位的确定方法建立了动态的不同规格掘进工程副产矿石的可利用边界品位指标,目的为强化矿山生产组织对副产矿石的管理,以稳定矿石品位为前提,提高矿山资源的综合利用率。     

电信级以太网的技术发展及其部署思路

电信级以太网正逐渐由标准化和试验走向现网部署和应用。虽然各种电信级以太网技术在可靠性保护能力方面有较大提升，但在服务质量（QoS）、操作、管理、维护（OAM）方面尚有待完善，多厂家互通性的问题也尤为突显。电信级以太网的部署应以满足业务需求为导向，综合考虑相关技术和标准的成熟度、部署成本、对现有网络改造的复杂度以及异厂商互通性等因素，根据技术特点为不同的应用场景灵活选择适当的组网技术。     

Determination of flavour compounds in a mountain cheese by headspace sorptive extraction-thermal desorption-capillary gas chromatography-mass spectrometry

Headspace sorptive extraction (HSSE) combined with thermal desorption (TD), gas chromatography (GC) and mass spectrometric detection (MSD) was applied to determine the volatile compounds of an Italian mountain cheese (Bitto) with protected designation of origin. Samples were taken from local dairy farms in Valtellina (Northern Italy), in which goats and cows were grazing on pastures during summer.A total of 84 compounds that belong to the following chemical families were detected and identified: aldehydes (17), ketones (10), esters (15), fatty acids (12), alcohols (11), terpenes (11) and hydrocarbons (8).The impact of each volatile compound on the flavour profile of Bitto cheese was discussed. The flavour profile of this cheese is important for the producer who wants to claim the right of naming cheese manufactured in a specified restricted area. Actually, this approach might become mainly useful for products, like Bitto cheese, with a PDO registration.HSSE coupled with thermal desorption and GC-MS analysis provided a versatile tool for the analysis of volatiles in cheese.     

Modelling the spatial distribution of a threatened butterfly: Impacts of scale and statistical technique

This paper compares the performance of five modelling methods in the prediction of a species distribution, using a data set describing the distribution of the threatened clouded apollo butterfly (Parnassius mnemosyne) in south-west Finland. The five statistical techniques included were: generalized linear models (GLM), generalized additive models (GAM), classification tree analysis (CTA), neural networks (ANN) and multiple adaptive regression splines (MARS). The accuracy of the models was examined at three spatial resolutions (1, 25 and 100 ha) by area under the curve (AUC) and kappa statistics. All five modelling techniques had a relatively high discrimination capacity for the occurrence of clouded apollo. Classification tree analysis provided the least robust model performance. The differences between the other methods were small, although GAM and MARS provided marginally the best stability and performance. The most accurate models were developed for the resolutions of 1 ha (highest AUC values) and 25 ha (highest kappa values) and the least accurate models for the resolution of 100 ha. Our work shows that modern modelling techniques can provide useful forecasts of species distributions in unsurveyed parts of landscapes and provide valuable contributions to conservation and management planning. However, the success of applying the new modelling tools can be influenced by the choice of statistical technique and especially of spatial resolution. In conclusion, small changes in the spatial scale may result in a clear decrease in the model performance and thus caution should be exercised when implementing the models and their predictions in practice.     

Non-invasive embedded system hardware/firmware anomaly detection based on the electric current signature

Quality control is a critical aspect of the modern electronic circuit industry. In addition to being a pre-requisite to proper functioning, circuit quality is closely related to safety, security, and economic issues. Quality control has been reached through system testing. Meanwhile, device miniaturization and multilayer Printed Circuit Boards have increased the electronic circuit test complexity considerably. Hence, traditional test processes based on manual inspections have become outdated and inefficient. More recently, the concept of Advanced Manufacturing or Industry 4.0 has enabled the manufacturing of customized products, tailored to the changing customers’ demands. This scenario points out additional requirements for electronic system testing: it demands a high degree of flexibility in production processes, short design and manufacturing cycles, and cost control. Thus, there is a demand for circuit testing systems that present effectiveness and accessibility without placing numerous test points. This work is focused on automated test solutions based on machine learning, which are becoming popular with advances in computational tools. We present a new testing approach that uses autoencoders to detect firmware or hardware anomalies based on the electric current signature. We built a test set-up using an embedded system development board to evaluate the proposed approach. We implemented six firmware versions that can run independently on the test board – one of them is considered anomaly-free. In order to obtain a reference frame to our results, two other classification techniques (a computer vision algorithm and a random forest classification model) were employed to detect anomalies on the same development board. The outcomes of the experiments demonstrated that the proposed test method is highly effective. For several test scenarios, the correct detection rate was above 99%. Test results showed that autoencoder and random forest approaches are effective. However, random forests require all data classes to be trained. Training an autoencoder, on the other hand, only requires the reference (anomaly-free) class.     

Evaluation of the reactive-sintered (Mn,Co)3O4 spinel layer for SOFC cathode-side contact application

Simulated interconnect/contact/cathode cells are used to investigate the performance of different contact precursors that are reactively sintered into spinel contact layers with nominal compositions of Mn_1.5Co_1.5O₄ and MnCo₂O₄, respectively. Both bare and Mn_1.5Co_1.5O₄-coated interconnects are employed in this study, where the Mn_1.5Co_1.5O₄ interconnect coating is also prepared via reactive sintering. The isothermal area specific resistance (ASR) of the test cells is evaluated at 800 °C in air for 2000 h. All the test cells exhibited excellent electrical behavior with ASR values of less than 10 mΩ·cm² during the measurement. The presence of the dense Mn_1.5Co_1.5O₄ coating leads to a better ASR performance. Cross-sectional observation of the test cells is conducted to assess the compatibility of the contact layer with adjacent components as well as its effectiveness in suppressing chromia scale growth and blocking Cr migration from the interconnect to the cathode.     

Communication network requirements for major smart grid applications in HAN,NAN and WAN

Since the introduction of the smart grid, accelerated deployment of various smart grid technologies and applications have been experienced. This allows the traditional power grid to become more reliable, resilient, and efficient. Despite such a widespread deployment, it is still not clear which communication technology solutions are the best fit to support grid applications. This is because different smart grid applications have different network requirements – in terms of data payloads, sampling rates, latency and reliability. Based on a variety of smart grid use cases and selected standards, this paper compiles information about different communication network requirements for different smart grid applications, ranging from those used in a Home Area Network (HAN), Neighborhood Area Network (NAN) and Wide-Area Network (WAN). Communication technologies used to support implementation of selected smart grid projects are also discussed. This paper is expected to serve as a comprehensive database of technology requirements and best practices for use by communication engineers when designing a smart grid network.     

Investigation of oxygen reduction reaction kinetics on Sm0.5Sr0.5CoO3−δ cathode supported on Ce0.85Sm0.075Nd0.075O2−δ electrolyte

Sm_0.5Sr_0.5CoO_3−δ (SSC) cathode prepared by a glycine-nitrate process (GNP) is investigated for solid oxide fuel cells (SOFCs) based on Ce_0.85Sm_0.075Nd_0.075O_2−δ (SNDC) electrolyte. SSC forms cubic perovskite structure after being annealed at 1100 °C for 5 h. SSC cathode and SNDC electrolyte can retain their own structure and there is no reaction between the two compositions. The microstructure of the cathode and the interfaces between cathodes and SNDC electrolytes are studied by scanning electron microscopy (SEM) after sintering at various temperatures. Impedance spectroscopy measurements reveal that area specific resistances (ASRs) of SSC-SNDC30 cathode are much lower than those of SSC cathode. Kinetics of oxygen reduction reaction (ORR) on porous SSC cathode is investigated by analysis of impedance spectra. Medium-frequency conductivities show no dependency on oxygen partial pressure (PO₂), which can be attributed to the oxygen ions transfer across the electrode/electrolyte interface. The dependencies of low-frequency conductivities on oxygen partial pressure (PO₂) vary in the range from ca. 0.31 to ca. 0.34 and increase with the increasing temperatures. The low-frequency electrode process is a mixing process involving oxygen reduction reaction related to atomic oxygen and oxygen ions conduction step together with total charge-transfer step. IR-compensated current density (i)-overpotential (η) relationship is established and the exchange current densities i_o originated from high-field approximations are much higher than those of low-field approximations and a.c. impedance data under OCV state. It demonstrates the polarization overpotential has great effect on the kinetics of ORR. The polarization current is observed to increase with time in the long-term stability measurement, which can be ascribed to the propagation process of oxygen vacancies.     

Development of a Fe-Cr alloy for interconnect application in intermediate temperature solid oxide fuel cells

The oxidation behavior and electrical property of a newly designed Fe-Cr alloy with addition of 1.05 wt.% Mn, 0.52 wt.% Ti, 2.09 wt.% Mo and other elements, such as La, Y and Zr have been investigated isothermally or cyclically at 750 °C in air for up to 1000 h. With a coefficient of thermal expansion matched to SOFC cell components, the alloy demonstrates excellent oxidation resistance and low area specific resistance of the oxide scale. The thermally grown oxide scale presents a multi-layered structure with conductive Mn-Cr spinel in-between the underneath Cr₂O₃ and the top Mn₂O₃. The oxidation rate constants obtained under both isothermal and cyclic oxidation condition are in the range of 5.1 × 10⁻¹⁴ to 7.6 × 10⁻¹⁴ g² cm⁻⁴ s⁻¹, and the measured area specific resistance at 750 °C after 1000 h oxidation is around 10 mΩ cm², lower than that of the conventional Fe-Cr stainless steels and comparable with that of the Ni-based alloys. Thermal cycling seems to improve the oxide scale adherence and promotes the formation of the highly conductive Mn₂O₃, and in turn, to enhance the oxidation resistance and electrical property.     

从工具理性到价值理性——历史街区交通和市政中的遗产保护优先性

我国历史街区的"建设性破坏",源自现代化进程中偏重高楼大厦、大马路等物质层面的工具理性目标,而忽视遗产保护、文化生态等制度、人口层面的价值理性目标。可持续发展观要求基于价值理性的技术应用目标(外部价值)回归到对基于工具理性的技术实现手段(内部价值)的控制地位。因此,历史街区交通和市政不能只追求先进、效率、性价比等技术内部价值,而应首先确保遗产保护目标的优先性,采取包括传统技术、"低技术"在内的任何适应该目标的技术手段。