采用铜铝复合管的翅片管换热器换热性能数值模拟与实验研究

提出采用一种铜铝复合管,用来替代传统的空调室外机换热器用铜管,可降低成本27.8%。首先通过数值模拟研究了Φ7管径的铜铝复合管与铜管翅片管换热器空气侧的传热与流动性能,计算结果表明,在入口风速为2.5m/s的情况下,与采用铜管的换热器相比,采用铜铝复合管的换热器空气侧的压力分布几乎不变,换热量降低3.12%,对性能影响较小。另一方面,对采用该模型的铜铝复合管换热器进行了性能测试,实验结果表明:铜铝复合管换热器换热量为8775W,与铜管换热器9101W相比降低3.58%,满足换热器标准要求。实验结果与数值模拟结果基本吻合,均证明这种新型铜铝复合管对换热器性能的影响不大,可用于空调的制造中。     

终冷温度对(B+M/A)X80管线钢组织-性能的影响

通过HOP技术,使X80管线钢获取了(B+M/A)复相组织。采用力学性能测试、显微分析和X射线衍射方法研究了在不同终冷温度条件下(B+M/A)X80管线钢的组织演变规律,分析了显微组织对力学性能的影响。结果表明,随着终冷温度的升高,贝氏体的板条宽度增加,贝氏体的含量和位错密度减小以及残余奥氏体量增加,导致材料强度降低和塑性增加。在高的终冷温度条件下,马氏体的形成、碳化物的析出和残余奥氏体的分解是材料强度增加和塑性减小的内在因素。在不同终冷温度下,实验钢的屈强比都小于0.85,均匀伸长率大于0.8%,形变强化指数大于0.10,符合大变形管线钢的技术要求。     

NURBS曲线插补技术在CNC中的应用

为了提高数控机床的加工精度和效率,在分析传统机床加工轮廓控制方案不足的基础上,提出了一种改进的NURBS曲线插补算法,该算法实现了基于S型速度曲线的加减速控制,并提出时间顺延法,加减速对称法等方法,合理解决了加减速点的预测问题,实现了在线实时自适应的加减速控制。     

ACC凝结水溶氧不合格的治理

以云冈热电厂为例，叙述了ACC凝结水溶氧不合格的原因，提出了治理方案。     

TP_SDDT的设计与实现

ＴＰ＿ＳＤＤＴ是Ｔｕｒｂｏ ＰＡＳＣＡＬ环境中一个有效的软件工具，凡是与语法有关的软件开发工作，如语法分析，元级操作和部分求值等，均可利用ＴＰ＿ＳＤＤＴ来完成，本文介绍了ＴＰ＿ＳＤＤＴ的设计思想及实现技术。ＴＰ＿ＳＤＤＴ已在微机上实现。     

TPS系统在300MW循环流化床机组中的应用及自动控制研究

应用TPS分散控制系统,建立起主机控制的一体化平台,发挥了蒙西发电厂300 MW循环流化床锅炉机组的DCS、DEH、ACC等一体化功能,提高了机组控制的可靠性。自动控制系统利用补偿、解耦、前馈等手段解决了大型循环流化床锅炉一次风量、床温、床压和协调控制等难点,有效提高了机组自动控制水平,为同类型机组自动控制研究提供了经验。TPS系统目前运行稳定,正常运行期间自动投入率在95%以上,达到了预期的设计目标。     

Estimation of Antenna Correlation Coefficient of N-Port Lossy MIMO Array

This paper proposes a simple yet accurate method for estimating the antenna correlation coefficient (ACC) of a high-order multiple-input multiple-output (MIMO) antenna. The conventional method employed to obtain the ACC from three-dimensional radiation patterns is costly and difficult to measure. An alternate method is to use the S-parameters, which can be easily measured using a network analyzer. However, this method assumes that the antennas are highly efficient, and it is therefore not suitable for lossy MIMO antenna arrays. To overcome this limitation, we define and utilize the non-coupled radiation efficiency in the S-parameter-based ACC formula. The accuracy of the proposed method is verified by the simulation results of a 4-port highly coupled lossy MIMO array. Further, the proposed method can be applied to N-port arrays by expanding the calculation matrix.     

The synthesis of long-term stable amorphous calcium carbonate in water-free ethylene glycol system without any phase stabilizer

Amorphous calcium carbonate (ACC) plays an important role in the biomineralization process and has a wide application in biological medicine area. In the present work, stable ACC was successfully prepared in water-free ethylene glycol system, by mixing the ethylene glycol solution of CaCl₂ and K₂CO₃ without phase stabilizer. The CaCO₃ obtained at different aging times (from 1 min to 3 months) and reaction temperatures (from 0 °C to 60 °C) were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected area electronic diffraction (SAED). XRD results indicate that ACC is the only phase in all samples and SAED results verify the existence of ACC. SEM and TEM images display that the irregular nano-particles were aggregated into irregular porous micro-particles, the pores become smaller with the aging time increase and the reaction temperature elevating, and some relative regular particles (near ellipsoidal or spherical) were formed when system is aged for a long time (3 months) at a low temperature (20 °C) or for a short time (30 min) at a high temperature (60 °C). As-synthesized ACC can be persistent in vacuum or organic solvent for a long time (1 month) at room temperature.     

Enhancement of lipid productivity in green microalgae Chlorella sp. via fast neutron irradiation

Microalgae is becoming a promising candidate for biofuel production and energetic lipid production, which urges the need to develop efficient methods for improvement of the lipid production. In this study, the neutron irradiation was employed to improve lipid production under different dosage irradiation. Effects of different dosages (No.1:8.14 × 10⁹, No.2:5.64 × 10⁸, No.4:9.42 × 10⁷ n/cm²) were compared by investigating associated algae cell growth, total lipid production, metabolization and enzyme activity. Dosages No.2 and No.4 improved the lipid content without negative influence on the growing, whereas irradiations shortened the period of biomass accumulation. The neutron irradiation in No.2 accelerated the synthesis of lipid from the carbohydrate transition process. In addition, the neutron irradiation not only increased the total lipid production by 20% but also speeded up the reaction rate to reach the maximal total lipid production in 28 days. Our results can provide a better understanding of the lipid production in microalgae Chlorella sp. by neutron irradiation, which are critical for evaluation of neutron irradiation based technologies for the sustainable and renewable biofuel production.     

保证二炼钢厂RH—KTB处理用汽的探讨

福钢二炼钢２台２７５ｔ转炉均停吹后,蒸汽量不能满足乖下的最后、包钢水进行ＲＨ－ＫＴＢ处理,针对此问题进行分析,并提出提高ＬＴ煤气冷却系统蒸汽蓄絷器的放汽压力是解决问题的有效措施。