炉衬材料和加热速率对铸造焦成块性能的影响

以煤粉、焦粉和煤沥青为原料,加水10%(w),捣固为500 mm×350 mm×400 mm的煤饼。入炉温度为650℃时,将煤饼放入单面加热炉内,炼焦终温为1050℃,在不同的加热速率下焦化为焦炭。研究了炉衬材料(黏土砖和硅砖)和加热速率(0.5、0.6、0.7℃·h^(-1))对煤饼自身升温速率和焦化后焦炭性能的影响。结果表明:由于硅砖的热导率优于黏土砖的,硅砖炉衬侧煤饼在水分挥发阶段时间较短,并在200~600℃煤饼第一收缩峰阶段自身升温速率较大,导致煤饼内部应力较大,焦炭块度较低。焦炉炭化室采用硅砖炉墙时加热速率宜在0.5℃·h^(-1),黏土砖作为炉墙时加热速率宜在0.6℃·h^(-1)。

浅议褐煤成块性的影响因素及对策

碎煤加压气化炉对煤炭的粒度有一定的要求,尤其是褐煤气化时,由于其具有水含量高、孔隙度大、机械强度低、热稳定性差等特点,其粒度范围要求在6～60mm。2008年在义马试烧锡盟东胜利2号煤矿褐煤中发现,进厂原煤和细粉较多,再经破碎和筛分后块煤利用率低,仅有41.9%,造成系统块、粉比失衡,粉煤过剩,热电装置无法消化。本文对褐煤破碎成块性的影响因素进行讨论,提出了风化和泥化造成的粉化现象以及破碎时出现的过粉碎现象等情况的对策。

Endoscopic ultrasound elastography for evaluation of lymph nodes and pancreatic masses:A multicenter study

AIM:To evaluate the ability of endoscopic ultrasound(EUS) elastography to distinguish benign from malignant pancreatic masses and lymph nodes.METHODS:A multicenter study was conducted and included 222 patients who underwent EUS examination with assessment of a pancreatic mass(n=121) or lymph node(n=101).The classification as benign or malignant,based on the real time elastography pattern,was compared with the classif ication based on the B-mode EUS images and with the fi nal diagnosis obtained by EUS-guided fi ne needle aspiration(EUS-FNA) and/or by surgical pathology.An interobserver study was performed.RESULTS:The sensitivity and specificity of EUS elastography to differentiate benign from malignant pancreatic lesions are 92.3% and 80.0%,respectively,compared to 92.3% and 68.9%,respectively,for the conventional B-mode images.The sensitivity and specificity of EUS elastography to differentiate benign from malignant lymph nodes was 91.8% and 82.5%,respectively,compared to 78.6% and 50.0%,respectively,for the B-mode images.The kappa coefficient was 0.785 for the pancreatic masses and 0.657 for the lymph nodes.CONCLUSION:EUS elastography is superior compared to conventional B-mode imaging and appears to be able to distinguish benign from malignant pancreatic masses and lymph nodes with a high sensitivity,specificity and accuracy.It might be reserved as a second line examination to help characterise pancreatic masses after negative EUS-FNA and might increase the yield of EUS-FNA for lymph nodes.

A Detailed Chunk-Level Performance Study of Web Page Retrieve Latency

It is a widely discussed question that where the web latency comes from. In this paper, we propose a novel chunk-level latency dependence model to give a better illustration of the web latency. Based on the fact that web content is delivered in chunk sequence, and clients care more about whole page retrieval latency, this paper carries out a detailed study on how the chunk sequence and relations affect the web retrieval latency. A series of thorough experiments are also conducted and data analysis are also made. The result is useful for further study on how to reduce the web latency.

Study on Simulation Method of Pipeline Networks' Dynamic Characteristic in Hydraulic Manifold Block

In the design of Hydraulic Manifold Blocks (HMB), dynamic performance of inner pipeline networks usually should be evaluated. To meet the design requirements, dynamic characteristic simulation is often needed. Based on comprehensive study on the existing simulation methods, a new method combined of Power Bond Graph(PBG) and Computational Fluid Dynamic (CFD) is proposed. In this method, flow field of typical channels inside HMB is analyzed with CFD to obtain the local resistance coefficients. Then, with these coefficients, a new sectional lumped-parameter model including kinetic friction factor is developed using PBG. A typical HMB design example is given and the comparison between the simulation and the experimental results demonstrates the feasibility and effectiveness of the proposed method.

Fabrication and performance analysis of a high-coupling-efficiency and convenient-integration optical transceiver

An optical transceiver with a novel optical subassembly structure is proposed in this paper, which achieves high coupling efficiency and low assembly difficulty. The proposed optical transceiver consumes 0.9 W power and retains a small size of 28 mmx16 mmx3 mm. The fabrication process of the silicon substrate and the assembly process of the optical transceiver are demonstrated in details. Moreover, the optical transceiver is measured in order to verify its transmission performance. The clear eye diagrams and the low bit error rate （BER） less than 1013 at 10 Gbit/s per channel show good transmission characteristics of the designed optical transceiver.

Effects of Cu,Fe and Co addition on the glass-forming ability and mechanical properties of Zr-Al-Ni bulk metallic glasses

The thermal stability,glass-forming ability(GFA) and mechanical properties of Zr60Al15Ni25xTMx(TM = Cu,Fe and Co,x = 0-10) bulk metallic glasses(BMGs) were systematically investigated.Additional 5-10 at.% Cu greatly enhances the thermal stability and GFA of the base alloy.Zr60Al15Ni15Cu10 BMG exhibits the largest supercooled liquid region of 104 K and critical diameter of 18 mm.However,addition of 5-10 at.% Fe or Co decrease the thermal stability and GFA.In addition,the plasticity of the BMG can be improved by adding of Cu,while the strength is decreased slightly.Zr60Al15Ni20Cu5 BMG has the largest plastic strain of 5.5% with a yield stress of 1755 MPa and Young's modulus of 83 GPa.Addition of Co brings an increase of strength but a lower of plasticity,and additional Fe reduces the strength and plasticity simultaneously.

Study of crystalline silicon solar cells with integrated bypass diodes

This paper reported a novel method of integrating bypass diodes into crystalline silicon solar cells.Bypass diodes which have the opposite p-n junction were formed by printing specific paste on the local surface of solar cells using screen printing,while infrared laser was applied to isolate the diode from the cell after firing.A module of crystalline silicon solar cells with integrated bypass diodes was fabricated and the I-V characteristics were measured under different shade conditions.The experimental results clearly showed that the integrated bypass diodes can effectively stabilize module's short circuit current while reduce the module power loss when shaded as well.