某岩溶地区钻孔灌注桩施工处理方案探讨

钻孔灌注桩在岩溶作用严重地区施工时，给运营线铁路的正常运行安全带来很大的安全隐患。根据不同的地质情况，本文通过具体的工程实例，介绍了片石黏土填塞法和水泥注浆法在钻孔灌注桩岩溶地区施工中的运用，从两种处理方案的选择方面做详细分析并给予处理解决措施，为以后相关工程提供借鉴。     

Assessment of wastewater pollution in pig leather industry in China

Pig leather industry contributed significantly to the life of people all over the world, but serious water environmental problems have arisen. Investigation in tanneries with green pig hides in China showed that pollution resulted mainly from beamhouse operations. Assessment indicated that wastewater from pig‐hides processing had: (1) wide variations of pH, (2) high levels of sulfide (S^2?) and chromium, (3) high levels of neutral salts and ammonia nitrogen (NH ₄⁺‐N), (4) high levels of suspended solids (TSS) and oil & grease, and (5) low biodegradability. A tannery processing 10 000 pig hides per day generated chemical oxygen demand (COD) of 3.81–12.31 tonnes and NH ₄⁺‐N 0.27–1.06 tonnes, respectively. The pollution loads were equivalent to those of a city of 60 000–120 000 inhabitants, which has a COD of 3.9–10.56 tonnes/day and NH ₄⁺‐N of 0.462–1.164 tonnes/day, respectively (SEPAC). And nearly 30% of the tanneries discharged their wastewater by screening only or by primary treatment like coagulation–sedimentation, while the rest of them discharged directly into surface waters without any treatment.     

DietCam: Automatic dietary assessment with mobile camera phones

Obesity has become a severe health problem in developed countries, and a healthy food intake has been recognized as the key factor for obesity prevention. This paper presents a mobile phone based system, DietCam, to help assess food intakes with few human interventions. DietCam only requires users to take three images or a short video around the meal, then it will do the rest. The experiments of DietCam in real restaurants verify the possibility of food recognition with vision techniques.     

An Analytical Model for Thermal Effect of Microcantilever-DNA Biosensors

The thermal effect of microcantilever-DNA biosensors is investigated by the energy method. Based on a liquid crystal theory for DNA solutions and a two-variable method for laminated cantilevers, an analytical model for nanomechanical cantilever motion under the combination of bio-interactions and thermal loadings is provided and then it is extended to T-shaped cantilevers. Then, the effects of chemo-physical properties of DNA biofilm (i.e., grafting density, nucleotide number, and ionic strength) and temperature change on deflections are discussed. In order to reduce noise signals, the controlling temperature and size optimization of cantilevers with different substrate materials and ionic strengths are also studied. Results show that SU-8 polymer cantilevers can preserve the sensitivity of molecule adsorption and thermal stability, which agrees well with the related experiments; the layer-to-layer thickness ratio of SU-8 polymer cantilevers should be as small as possible, while for silicon nitride cantilevers, there exists an optimal value. These results help to understand the sensitivity and reproducibility of biosensors.     

Compact see‐through near‐eye display with depth adaption

Based on the recent development of Pancharatnam–Berry deflectors and lenses, we propose a compact and lightweight near‐eye display system with depth adaption. The compact design results from the polarization selectivity of Pancharatnam–Berry deflector waveguide coupler, and the fast‐switching Pancharatnam–Berry lenses can be exploited for generating correct light fields.     

Preparation of iron and nitrogen co-doped carbon material Fe/N-CCM-T for oxygen reduction reaction

In this paper, iron and nitrogen co-doped carbon material with nanotube structure (Fe/N-C_CM-T) was synthesized by pyrolyzing a mixture of Fe salt, chitosan and melamine and displayed high electrocatalytic performance for oxygen reduction reaction (ORR). The structure of the Fe/N-C_CM-T was characterized and their ORR performance in alkaline media was investigated by linear sweep voltammetry, cyclic voltammetry and chronoamperometry. Fe/N-C_CM-T displayed better ORR performance than other carbon materials like Fe/N-C_C-800. The Fe/N-C_CM-800 with a large surface area (302.5 m²/g) especially exhibited the best ORR electrocatalytic performance among the prepared carbon materials, which was also proved by its similar Tafel slope (76 mV decade^?1) to Pt/C catalyst (74 mV decade^?1). Fe/N-C_CM-800 showed similar ORR activity as commercial Pt/C catalyst, but superior tolerance to methanol and stability. Such high ORR performance of the Fe/N-C_CM-T can be attributed to its nanotube structure, high specific surface area (SSA), high graphitic-N and pyridinic-N contents.     

A scheme for the simultaneous measurement of atomic position and momentum

Abstract

We propose an optical scheme for the simultaneous measurement of the position and momentum of a single atom. The scheme involves the coupling of the atom of two light fields with different spatial and polarization characteristics. The proposed technique is closely related to the Arthurs-Kelly measurement scheme; the principal difference is that in the present case the values of the position and momentum are inferred from phase shifts in electromagnetic fields rather than from shifts in the position of a pointer.     

3CIMX4型透平机组主油泵故障分析及优化改造

针对某透平机组主油泵频繁发生故障,进行了原因分析,找出了主因,并对其进行了优化改造,有效避免了事故的发生。     

Body Sensor Network Based Context-Aware QRS Detection

In this paper, a body sensor network (BSN) based context-aware QRS detection scheme is proposed. The algorithm uses the context information provided by the body sensor network to improve the QRS detection performance by dynamically selecting those leads with the best SNR and taking advantage of the best features of two complementary detection algorithms. The accelerometer data from the BSN are used to classify the daily activities of patients and provide context information. The classification results indicate the types of activities that were engaged in. They also indicate their corresponding intensity, which is related to the signal-to-noise ratio (SNR) of the ECG recordings. Activity intensity is first fed to the lead selector to eliminate those leads with low SNR, and then is fed to a selector to select a proper QRS detector according to the noise level. An MIT-BIH noise stress test database is used to evaluate the algorithms.     

基于GIS的玛纳斯河灌区信息系统设计与应用

为进一步提高水资源利用的效率和灌区管理水平，本文针对玛纳斯灌区的实际情况，提出空间信息与灌区业务管理信息有机融合的理念，依据业务管理需求，设计了灌区信息系统的体系结构并定义了系统功能。在对灌区的量测水方法进行研究的基础上，玛纳斯灌区信息系统实现了灌区信息管理中的监测监控、量水测水、配水调度、水费计收以及防汛和工程运行管理等业务工作的自动化和智能化。