凡口铅锌矿机械化凿岩装药的爆破效果分析

凡口铅锌矿根据生产需要,采用机械化凿岩台车凿岩、小装药台车装药爆破。通过现场实际试验,发现与人工凿岩相比,凿岩台车凿岩爆破效果显著提高,小装药台车装药爆破效果较人工装药爆破效果差。分析认为小装药台车装药爆破效果取决于对装药台车本身的正确使用,凡口铅锌矿还需在实际生产中进一步探索适合本矿的装药台车装药方法。

汽轮机给水泵检修中需注意的问题

汽轮机给水泵检修不单单是对汽轮机给水泵组件的简单检查,而是应该站在维护汽轮机给水泵功能,确保汽轮机运行和实现火电厂生产稳定的高度上,以过程性、系统性、全面性的措施对汽轮机给水泵进行严格检验与维修,进而有力保障汽轮机给水泵的运转性能。本研究以汽轮机给水泵检修的工作经验为出发点,从汽轮机给水泵检修的测量、检测、小装、总装、调整等工作出发,介绍了检修汽轮机给水泵过程中应该注意技术与操作的关键。

脉动真空压力蒸汽灭菌器常见故障处理

脉动真空压力蒸汽灭菌器是以饱和水蒸汽作为灭菌介质,采用机械强制脉动真空的空气排除方式,经多次抽真空多次注入蒸汽交替作用;将内室空气强制排空,彻底消除灭菌室内的冷点,使空气排出量达到99%以上,完全排出温度死角和小装量效应,保障了可靠的灭菌效果。它是目前医学领域使用最广泛、灭菌效果最可靠的一种灭菌设备。

Dynamics of Micelle Formation from Mixed Lipid Droplets

Amphiphilic lipid molecules can form various micelles depending on not only their molecular composition but also their self-assembly pathway. In this work, coarse-grained molecular dynamics simulations have been applied to study the micellization behaviors of mixed dipalmitoylphosphatidylcholine （DPPC）/hexadecylphosphocholine （HPC） droplets. By vary- ing DPPC/HPC composition and the size of lipid droplets, various micelles such as spherical and nonspherical （oblate or prolate） vesicles, disk-like micelles, double or single ring-like and worm-like micelles were observed. It is found that the lipid droplet as an initial state favors forming vesicles and ring-like micelles due to in situ micellization. Our simulation results demonstrate that using special initial conditions combined with various molecular compositions is an effective way to tune lipid micellar structure.

Development of CAPP System for Small and Medium Size Apparel Enterprises

Existing computer-aided process planning （CAPP） systems for garment manufacturing emphasize all-purpose ones, lack specialism and availability. So, few developed is popular in the garment industries. This study is intended for developing a CAPP system, which aims at the actual condition of process planning in the small and medium size apparel enterprises （SMAs）. It enables the technologists of process planning to be quicker in generating suitable plans that are similar to existing styles or new. It also automatically provides labor cost by considering the shop-ricer caztiticns. Process planning is achieved by adopting the Hybrid Interactive-variant process planning mete. The proposed system has been realized in Borland Delphi 7 and Orade 8. For validation of the system, the software has been implemented successfully in a firm named Jingchen in China.

New predictive control algorithms based on Least Squares Support Vector Machines

Used for industrial process with different degree of nonlinearity, the two predictive control algorithms presented in this paper are based on Least Squares Support Vector Machines (LS-SVM) model. For the weakly nonlinear system, the system model is built by using LS-SVM with linear kernel function, and then the obtained linear LS-SVM model is transformed into linear input-output relation of the controlled system. However, for the strongly nonlinear system, the off-line model of the controlled system is built by using LS-SVM with Radial Basis Function (RBF) kernel. The obtained nonlinear LS-SVM model is linearized at each sampling instant of system running, after which the on-line linear input-output model of the system is built. Based on the obtained linear input-output model, the Generalized Predictive Control (GPC) algorithm is employed to implement predictive control for the controlled plant in both algorithms. The simulation results after the presented algorithms were implemented in two different industrial processes model; respectively revealed the effectiveness and merit of both algorithms.

The in vitro reconstitution of nucleosome and its binding patterns with HMG1/2 and HMG14/17 proteins

Using atomic force microscopy (AFM), the dynamic process of the in vitro nucleosome reconstitution followed by slow dilution from high salt to low salt was visualized. Data showed that the histone octamers were dissociated from DNA at 1M NaCl. When the salt concentration was slowly reduced to 650 mMand 300 mM, the core histones bound to the naked DNA gradually. Once the salt concentration was reduced to 50 mM the classic 'beads-on-a-string' structure was clearly visualized. Furthermore, using the technique of the in vitro reconstitution ofnucleosome,the mono- and di- nucleosomes were assembled in vitro with both HS2core (-10681 to -10970 bp) and NCR2 (-372to -194 bp) DNA sequences in the 5'flanking sequence of human b-globin gene. Data revealed that HMG 1/2 and HMG 14/17 proteins binding to both DNA sequences are changeable following the assembly and disassembly of nucleosomes. We suggest that the changeable binding patterns of HMG 14/17 and HMG1/2 proteins with these regulatory elements may be critical in the process of nucleosome assembly, recruitment of chromatin-modifying activities, and the regulation of human b-globin gene expression.

Minimal Enclosing of an MPT (v,λ) in a TS (u,λ+1)

Let MPT (v,λ) denote a maximum packing of triples of order v with index λ and TS (u,λ) denote a triple system of order u with index λ. In this paper, for v≥6, we determine necessary and sufficient condition for enclosing an MPT (v,λ) in a TS (v+m,λ+1) with index λ increased by 1 and minimal increase in extra points.

Equipping the Public Primary Schools in Puebla： The Case of the Enciclomedia System in the State of Puebla, Mexico

The primary school system in Mexico is affected by serious shortfalls in the installation of related information and communication technologies resources in the teaching-learning process. This lack of resources has an impact of the context of the digital divide as well as in joining the knowledge society. The present article will deal with the outfitting of classrooms with the enciclomedia system in the 5tb and 6th grade in the State of Puebla. It will demonstrate important findings, demonstrating the deepening digital divide between the state capital and the rest of the municipalities in this state. In fact, the furthest （300 km far away from Puebla city） the less primary school equipped with the enciclomedia system. We will also demonstrate the resource distribution by school-type and inhabitants. Another finding is the influence in resource distribution by political party. This study should provide public policy decision-makers with valuable information for the apportionment of resources in all municipalities of the State of Puebla.

Influences of Organic Solvents on Particle Size and Drug-loading Efficiency for 5-Fluorouracil Poly(lactic acid)Nanoparticles

The objective of this study was to investigate the influences of organic solvents on particle size, drug content, loading efficiency and yield for 5 Fluorouracil Poly(lactic acid) nanoparticles . The 5 Fluorouracil was entrapped into poly(lactic acid)(PLA) nanoparticles using a water in oil in water solvent evaporation technique. During the preparation process, ethyl acetate and acetone were used as organic solvents since they are less toxic than the more commonly used dichloromethane. The effect of the three solvents on particle size, drug content, loading efficiency and yield of nanopartcles was compared. When the solvent of the oil phase was acetone, the highest drug content, smallest particle size and lowest yield were obtained for the PLA nanoparticles.

A heuristic method for solving triangle packing problem

Given a set of triangles and a rectangle container, the triangle packing problem is to determine if these triangles can be placed into the container without overlapping. Triangle packing problem is a special case of polygon packing problem and also NP-hard, so it is unlikely that an efficient and exact algorithm can be developed to solve this problem. In this paper, a new concept of rigid placement is proposed, based on which a discrete solution space called rigid solution space is constructed. Each solution in the rigid solution space can be built by continuously applying legal rigid placements one by one until all the triangles are placed into the rectangle container without overlapping. The proposed Least-Destruction-First (LDF) strategy determines which rigid placement has the privilege to go into the rectangle container. Based on this, a heuristic algorithm is proposed to solve the problem. Combining Least-Destruction-First strategy with backtracking, the corresponding backtracking algorithm is proposed. Computa- tional results show that our proposed algorithms are efficient and robust. With slight modification, these techniques can be con- veniently used for solving polygon packing problem.

Application of least squares vector machines in modelling water vapor and carbon dioxide fluxes over a cropland

Least squares support vector machines (LS-SVMs), a nonlinear kemel based machine was introduced to investigate the prospects of application of this approach in modelling water vapor and carbon dioxide fluxes above a summer maize field using the dataset obtained in the North China Plain with eddy covariance technique. The performances of the LS-SVMs were compared to the corresponding models obtained with radial basis function (RBF) neural networks. The results indicated the trained LS-SVMs with a radial basis function kernel had satisfactory performance in modelling surface fluxes; its excellent approximation and generalization property shed new light on the study on complex processes in ecosystem.

An empirical study on vortex-generator insert fitted in tubular heat exchangers with dilute Cu–water nanofluid flow

The heat transfer enhancement(HTE) in tubular heat exchangers fitted with vortex-generator(VG) inserts is experimentally investigated. The studied four parameters and ranges are: winglets-pitch ratio(1.33, 2.67, and 4),winglets-length ratio(0.33, 0.67, and 1), winglets-width ratio(0.2, 0.4, and 0.6), and Reynolds number(5200to 12200). The testing fluids are the water and Cu–water nanofluid at the volumetric fraction of 0.2%. The results obtained on HTE, pressure drop, and performance evaluation criterion(PEC) are compared with those for water in a smooth tube. It is found that the VG inserts with lower winglets-pitch ratio and higher winglets-length/width ratios present higher values of HTE and pressure drop. Over the range studied, the maximum PEC of 1.83 is detected with the Cu–water nanofluid inside the tube equipped with a VG insert at the winglets-width ratio of0.6 for the maximum Reynolds number, when the heat transfer rate and pressure drop are 1.24 times and 2.03 times of those in the smooth tube. Generalized regression equations of the Nusselt number, friction factor, and PEC are presented for the tubular heat exchangers with the VG inserts for both water and Cu–water nanofluid.It is concluded that the main advantage of the VG inserts is their simple fabrication and considerable performance, particularly at higher Reynolds number.

CL-20基炸药油墨的直写成型及性能研究

以六硝基六氮杂异伍兹烷(CL-20)作为主体炸药,乙基纤维素(EC)及聚叠氮类粘结剂为粘结剂,乙酸乙酯为溶剂,配制出一种全溶性炸药油墨。采用微控直写工艺将该炸药油墨在基板上进行了书写,并对成型后所得复合物的性能进行了测试和表征。结果表明:成型样品中CL-20颗粒形貌为球形,颗粒尺寸小于1μm,均匀分布在粘结体系基体中;成型样品的密度为1.66 g/cm^3,达到理论密度的85.5%;和原料CL-20相比,复合物的撞击感度得到明显降低,特性落高比原料CL-20高出21.5cm。该配方具有良好的传爆性能,1.2mm装药宽度下,爆轰临界尺寸为0.357mm。

Investigation of a New Vortex-Induced Vibration Suppression Device in Laboratory Experiments

In order to mitigate vortex-induced vibration (VIV) of marine risers, especially to eliminate the phenomenon of frequency 'lock-in', a new suppression device of crescent-shaped flow spoiler was designed with seven different layout schemes. VIV model tests with six flow levels were conducted in a large wind-wave-current flume. In all cases, vibration responses in both in-line and cross-flow cases were measured. With the installation of suppression devices vibration frequency evolution of a riser was analyzed by Morlet wavelet transform. The principle of VIV suppression was interpreted through vibration characteristics. Fatigue life of the riser was calculated by the Palmgren-Miner rule. Compared with a bare riser, vibration of an outfitted riser with suppression devices disturbed the steady flow, the vibration amplitudes in the two flow directions were reduced, and the riser fatigue life was improved.

Methodology for Defining of Eligible Capacity for Wood Fuel Based Cogeneration Plants in Small Towns in Estonia

There is a high potential for small-scale and medium scale wood-fired cogeneration in Estonia. The purpose of this research is to define the eligible capacity for wood fuel based cogeneration plant operating on the base of district heating systems in small towns. Results were checked and approbated by economical and environmental factors. Two optimal sizing methods were used maximizing of amount of heat year-round while working at full installed capacity and maximizing of amount of heat year-round while working with partial loads. Results of defining optimal capacities for wood-fired cogeneration plants in small Estonian towns showed that method of maximizing of amount of heat year-round while working with partial loads is more adequate to real situation.

Human Body Image Edge Detection Based on Wavelet Transform

Human dresses are different in thousands way. Human body image signals have big noise, a poor light and shade contrast and a narrow range of gray gradation distribution. The application of a traditional grads method or gray method to detect human body image edges can't obtain satisfactory results because of false detections and missed detections. According to the peculiarity of human body image, dyadic wavelet transform of cubic spline is successfully applied to detect the face and profile edges of human body image and Mallat algorithm is used in the wavelet decomposition in this paper.

Preparation of Nano-sized Silica-alumina Support by Supersolubilizing Self-assembly Technique

Nano-sized silica-alumina particles were in-situ synthesized in supersolubilizing reverse micellae.Both the most probable pore diameters and the particle sizes were distributed in nano-scale SiO2-Al2O3 particulates.The influence of SiO2/Al2O3 mass ratio and the surfactant content on the particle size and morphology,pore structure,and acidity was characterized by the low temperature nitrogen adsorption/desorption (BET),SEM,TEM and NH3-TPD methods.The test results indicated that the most probable pore diameter of SiO2-Al2O3 nanoparticles was around 10 nm,the specific surface area was about 223-286 m2 /g,the pore volumes were about 0.48-0.63 cm 3 /g,and the particle sizes of porous SiO2-Al2O3 calcined at 550 ℃ were distributed always in the range between 10 nm to 50 nm.The calcined SiO2-Al2O3 nano-powders showed their acidity being stronger than the porous γ-Al2O3 support.