钢的粉末渗硼

渗硼能显著地提高钢件表面硬度和耐磨性.渗硼层并具有良好的耐蚀能力和高温抗氧化性能.因此近年来渗硼工艺发展很快.在电力、化工、机械等工业方面应用日渐广泛.渗硼的方法很多,有固体法(膏状渗硼和粉末渗硼)、液体法、气体法及电解法等,其中固体膏状渗硼已在电站钻炉排污阀门上推广使用.我厂在膏剂渗硼基础上,从80年进行固体粉末渗硼的试验和摸索.采用粉末渗硼具有设备简单,操作方便,成本低,渗硼件表面光滑.渗硼层结构易于控制等优点.     

固体渗硼应用情况介绍

钢件渗硼后,在零件表面可生成一层高硬度的硼化层,因而具有良好的耐磨性。目前我厂固体渗硼已应用在定期排污阀门,给水调节阀,高压水力排灰机等易磨易损件上。一、渗硼方法与要求我厂采用的是固体渗硼方法,渗硼剂主要是:碳化硼(B_4C)、粒度(180～200目),其配方为:50%(B_4C),25%(CaF_2),25%(NaSiF_6)。将其混合均匀,然后用桃     

无机添加剂Na2SO3对石墨负极性能的改善

在1 mol/L LiPF6/EC+EMC电解液中添加少量的Na2SO3,通过与空白溶液比较显示添加Na2SO3能显著提高天然石墨负极充放电容量,降低首次循环过程中的不可逆容量损失,提高电极的循环性能和倍率充放电性能;电极表面SEI膜组分的FTIR分析和扫描电镜表明,添加一定量的Na2SO3在动力学方面有助于形成Li+...     

添加剂Na2CO3对石墨电极性能的影响

在电解液1 mol/L LiPF6/EC+DMC中加入碳酸钠(Na2CO3),通过SEM、循环伏安和电化学阻抗谱分析,研究了Na2CO3对石墨电极的影响。添加饱和Na2CO3,可促进在石墨电极表面形成更稳定的固体电解质相界面(SEI)膜,抑制循环过程中电解液的进一步还原分解,增进Li+嵌脱过程的可逆性,改善石墨电极的电化学性能。     

P91钢主蒸汽管道焊缝金相缺陷形态及其形成原因探讨

通过对表面有微裂纹的P91钢主蒸汽管道焊缝取样试验分析,认为焊缝金相缺陷主要有3种形态：表面微裂纹、线状缺陷（晶间网状或线状析出物偏聚）及粗大的柱状晶。以钢的焊接熔池凝固、相变及多层多道焊层之间热影响区相变理论为基础,对金相缺陷形成机理进行探讨,金相缺陷的直接危害是焊缝冲击韧性极低（小于10J）。焊接线能量过大是产生焊缝金相缺陷的主要原因。     

固体B—V—Re共渗新工艺及其在引风机叶轮防磨上的应用

采用固体Ｂ－Ｖ－Ｒｅ共渗处理，４５钢及１６Ｍｎ钢表面可获得ＨＶ１－７００－２４０的高硬度，经层深度大于２００μｍ。     

碳酸钙直接硫化反应产物层固态离子扩散机理研究

循环流化床富氧燃烧因其可对再循环烟气温度有效控制，被称为最有工业前景的控制温室气体技术之一。在该燃烧方式下，煤燃烧产生的SO2仍采用石灰石除掉，但该过程属于石灰石的直接硫化反应。此反应目前争议较多的为硫化反应产物层中的扩散物质种类问题。文中采用向石灰石中添加Na2CO3的方法，对其循环流化床富氧燃烧工况下的硫化特性进行研究，目的在于探讨硫化反应产物层中的扩散机理及添加剂对石灰石硫化反应的作用。结果表明Na2CO3对石灰石在富氧气氛下直接硫化反应具有明显的促进作用，而且随反应进行，这种促进作用相对更加显著。SEM分析表明经Na2CO3处理后的石灰石硫化后所形成的CaSO4产物层中CaSO4晶粒较原始石灰石硫化后所形成CaSO4晶粒小，且晶粒之间排列更不规则。Na2CO3的添加导致硫化产物层中缺陷浓度增加，从而加速了产物层中的离子扩散率，是使石灰石直接硫化的最终转化率和硫化速率升高的原因。这也给石灰石直接硫化反应产物层中固态离子扩散理论提供了进一步的依据。     

固体渗硼工艺

工件固体渗硼是在工业学大庆的群众运动蓬勃发展,技术革新和技术革命不断深入发展的大好形势下开展起来的。我们获悉武汉青山电厂采用膏剂渗硼的联合阀门,为国家节省了大量的优质钢材和检修工时,为此我厂由锅炉、汽机、修配三个车间组成三结合小组研制工件渗硼。在学习武汉青山电厂的先进经验的基础上,经过20多炉300多个试样和工件(低炭钢焊条堆焊的门口、中炭钢门杆、瓦拉口、2铬13不锈钢、联合阀门等工件)的反复实践,现已基本成功。经过渗硼的工件硬度高,耐磨性好,防腐性好,从而提高了工件的使用寿命,减少检修次数。同时可以用炭素钢渗硼代替高级合金钢使用,节约原材料,而且在安全发、供电上起到良好的作用。我厂四号炉安装一个渗硼联合阀门,经过半年多的运行情况良好,目前仍在运行使用。     

38CrMoAlA钢可控抗蚀氮化

本文介绍可控井式氮化炉合理控制氮化温度、时间和氨分解率的渗氮工艺 ,使 38CrMoAlA钢试样表面获得致密而无脆的ε相白亮层和扩散层渗层组织 ,对渗氮后试样实测表明 ,该试样显微组织、脆性、显微硬度、渗层深度和抗蚀性均符合技术要求     

Mn-Mo-B-RE系铸态钢中的硼分布

研究了Mn Mo B RE系低合金铸钢中硼的偏析和均匀化、正火、调质热处理过程中硼分布的变化 ,以及稀土元素加入和钢中Mo等元素对硼分布的影响 .硼在铸钢中有明显的偏析现象 ,经正常的均匀化处理后 ,铸钢中硼分布的均匀性受Mo的偏析强烈影响 .在特定的条件下 ,会产生沿奥氏体一定结晶学平面的硼相析出 ,会沿晶界形成粗大连续网状的硼相 ,导致脆断 .结果表明稀土元素可以抑制硼的偏析 ,从而起到保护硼的作用 .     

无氧条件下Na、K、Fe对生物质焦炭脱硝效率影响的试验研究

生物质中Na、K、Fe含量较高,对低氮燃烧所采用的再燃脱硝过程有利。为有效利用中国的生物质资源,有必要对生物质焦炭的脱硝性能进行研究,为此在固定床系统上研究了无氧条件下Na、K、Fe对异相脱硝反应的影响。试验结果表明,适量的Na、K、Fe可以大大提高生物质焦炭的脱硝效率,在酸洗后的生物质焦炭中添加Na、K、Fe会使得脱硝效率显著增加。其中,当生物质焦炭与Na2CO3或K2CO3的质量之比为0.1时,生物质焦炭的脱硝效率可增加20%以上,且脱硝效率随Na、K添加量的增加而增加;Fe对生物质焦炭脱硝效率的促进效果明显优于Na、K元素,生物质焦炭与Fe（ＮＯ３）3·9H2O质量之比为0.01时即可使生物质焦炭的脱硝效率增加20%左右,但当二者质量之比超过0.04时,生物质焦炭的脱硝效率随Fe添加量的增加而降低。     

Evolution of ferroelectric and piezoelectric response by heat treatment in pseudocubic BiFeO<Subscript>3</Subscript>–BaTiO<Subscript>3</Subscript> ceramics

Heat treatment of ceramics is an important process to tailor the fine electromechanical properties. To explore the criteria for optimized heat treatment in a perovskite structure of (1–x)Bi_1.05FeO₃–xBaTiO₃ (BF–BT100x) system, the structural phase relation, ferroelectric and piezoelectric response of BF–BT36 and BF–BT40 ceramics prepared by furnace cooling (FC) and quenching process were investigated. The X-ray diffraction examination showed single pseudocubic perovskite structure for all the ceramics. The homogenous microstructure was obtained for all ceramics with relatively large grain size in the furnace cooled samples. Well saturated ferroelectric hysteresis loops and enhanced piezoelectric constant (d₃₃?=?97 pC/N) were achieved by quenching process. Dielectric curve of BF–BT36 showed large dielectric constant at its Curie temperature, however, BF–BT40 showed diffused relaxor-like dielectric anomalies. Quenched BF–BT36 samples showed typical butterfly like field induced strain curves, however negative strain decreased in BF–BT40 ceramics. From these investigated study, it is observed that BF–BT ceramics are very sensitive to the heat treatment process (furnace cooling and quenching) on the dielectric, electromechanical properties.     

碳酸钠的浓度对镁铝水滑石阻燃剂制备的影响

在常压下用一步反应液相法制备了镁铝水滑石阻燃剂试样。研究了碳酸钠的浓度变化对制备试样的影响。根据不同碳酸钠浓度下制备的试样的XPD和IR测试发现：碳酸钠浓度的变化对制备得的镁铝水滑石试样的纯度几乎没有影响，但影响了镁铝水滑石晶体中间层中的CO3^2-的对称性的高低以及中间层内的CO3^2-与水分子分布的有序性，进而影响了镁铝水滑石晶体基本层上阳离子的分布状况。结果表明当选择镁离子的浓度为0．06mol／L、镁离子与铝离子的摩尔比为3：1制备镁铝水滑石时。碳酸钠较为合适的浓度是10g/L。     

聚醚固体电解质锂电池放电性能研究

利用氧亚甲基连接的聚氧乙烯-聚氧丙烯多嵌段共聚物或氧亚甲基连接的聚氧乙烯多嵌段共聚物与高氯酸锂的络合物作电池的电解质,锂片作负极,几种含钒的化合物作正极,组装了全固态二次锂电池.研究了不同正极材料、不同电解质和不同温度对电池短路放电性能的影响以及电池的重复短路放电性能.研究表明,正极材料V_6O_(13)的性能优于Na_(1+x)V_3O_8;电解质(PEO)_n·LiClO_4的性能优于(PEO-PPO)_n·LiClO_4,这与它们的电导率分别为3.2×10~(-3)S·cm~(-1)和2.2×10~(-3)S·cm~(-1)是一致的.     

稻秆与煤混燃过程中碱金属迁移转化规律研究

以化学热力学平衡计算为基础,利用自行设计的立式管式炉结合X射线衍射(X-ray power diffraction,XRD)、扫描电子显微镜(scanning election microscope,SEM)等分析测试手段探讨稻秆与煤在850℃的条件下混合燃烧碱金属K、Na的迁移转化规律。结果表明,碱金属的主要气态组元KCl、KOH、NaCl、NaOH随稻秆含量的增多而增加,且氯化物的析出量大于氢氧化物的析出量;煤中某些矿物组分或元素对K的气相析出有抑制作用,但对Na的抑制作用不明显;灰中K、Na的存在形式直接受原料秸秆含量的影响,稻秆含量为0%和20%时,灰中K以K2O Fe2O3为主,Na则以Na2SO4为主,稻秆含量大于50%时,K2O 2SiO2、Na2SiO3随稻秆含量的增多表现出上升趋势,K2SO4、Na2SO4趋势则相反,原料K还会以KAlSiO4、KAlSi3O8的形式滞留在灰中。     

Simultaneous removal of NO/sub x/, SO/sub x/, and CO/sub 2/ at elevated temperature using a plasma-chemical hybrid process

In previous studies, the authors confirmed that the plasma-chemical combined hybrid process for controlling NO flue gas emission was extremely effective and economical in comparison with the conventional selective catalytic reduction (SCR) system and other technologies. In the present study, we carried out experiments on the simultaneous removal of NO/sub x/ and SO/sub x/ at elevated temperature using the plasma-chemical hybrid process. A series of experiments was performed to quantify all the reaction byproducts such as N/sub 2/O, CO, HNO/sub 2/, HNO/sub 3/, NO/sub 3//sup -/, and SO/sub 4//sup -/ to evaluate the simultaneous NO/sub x/ and SO/sub x/ removal efficiency. The oxidation from NO to NO/sub 2/ without decreasing NO/sub x/ concentration (i.e., minimum reaction byproducts) and with least power consumption is the key for the optimum operation of the plasma reactor. The produced NO/sub 2/ was totally converted to N/sub 2/ and Na/sub 2/SO/sub 4/ with Na/sub 2/SO/sub 3/ or Na/sub 2/S with and without NaOH using the barrier-type packed-bed plasma reactor followed by the packed-column chemical reactor. The NO/sub 2/ reduction was more effective for Na/sub 2/S than Na/sub 2/SO/sub 3/ but produces H/sub 2/S with Na/sub 2/S. For both cases at least five times the stoichiometric amount of chemicals were required for complete NO/sub 2/ reduction. Nearly 100% of NO/sub x/ and SO /sub 2/ and 40% Of CO/sub 2/ simultaneous removal were achieved with less than 5 ppm of N/sub 2/O and CO. The operating cost was less than 1/4 the SCR process. The additional SO/sub 2/ treatment system can be eliminated.     

Enhanced Numerical Breaker Failure Protection

Breaker failure (BF) protection provides backup for circuit breakers (CBs) and associated control wiring. Traditionally, CBs are not duplicated, but monitored by BF relays when ordered to trip. Upon a failure of a breaker to interrupt the current, the BF relay opens adjacent breakers to isolate the problem. The total trip time under a BF condition is often tightly fit into the critical fault clearance time as determined by system stability. With narrow stability limits in today's power systems, coordination margins for the operation of BF functions are becoming scarce. This imposes a requirement for the fast reset time of BF protection. In its first part, this paper presents a novel algorithm for numerical current-based BF function with a fast 0.5-cycle reset time even under severe subsidence current. In the second part, the paper addressed the problem of fast and secure recognition of binary inputs for both BF initiation and BF detection based on the auxiliary breaker contacts. This novel algorithm works with analog representation of binary signals and provides security under induced transients, battery ground faults, and other interfering events.     

托克托电厂阻塞滤波器引发机组异步自励磁的分析

针对托克托电厂阻塞滤波器(blocking filter,BF)运行中出现的异步自励磁现象,从电路原理、特征值分析和电磁仿真3个方面分析了其机理。在电路原理上,分析了BF非线性阻抗频率特性,阐明BF在特定频率段内呈强容性和弱阻性是其与机网形成串联型参数谐振进而导致异步自励磁的内在原因。然后采用特征值方法定量分析了异步自励磁的稳定性,以及机、网和BF参数对自励磁风险的灵敏度的影响。最后基于详细电磁仿真复现8号机BF投运试验中出现的异步自励磁现象,对比仿真和现场试验结果,验证了电路和特征值分析的正确性,为进一步修正BF设计、解决托克托电厂次同步谐振问题奠定了基础。     

Effects of linear versus sigmoid coding of visual or audio biofeedback for the control of upright stance.

Although both visual and audio biofeedback (BF) systems for postural control can reduce sway during stance, a direct comparison between the two systems has never been done. Further, comparing different coding designs of audio and visual BF may help in elucidating how BF information is integrated in the control of posture, and may improve knowledge for the design of innovative BF systems for postural control. The purpose of this paper is to compare the effects of linear versus sigmoid coding of trunk acceleration for audio and visual BF on postural sway in a group of eight, healthy subjects while standing on a foam surface. Results showed that sigmoid-coded audio BF reduced sway acceleration more than did a linear-coded audio BF, whereas a linear-coded visual BF reduced sway acceleration more than a sigmoid-coded visual BF. In addition, audio BF had larger effects on reducing center of pressure (COP) displacement whereas visual BF had larger effects on reducing trunk sway. These results suggest that audio and visual BF for postural control benefit from different types of sensory coding and each type of BF may encourage a different type of postural sway strategy.