IRIS reactor core with thorium fuel

This work is aimed at running the first IRIS reactor core with mixed thorium dioxide fuel（ThO₂-UO₂ and ThO₂-PuO₂）.Calculations are performed by using Dragon 4.0.4 and Citation codes.The results show the multiplication factor(K_eff) for central and peripheral assemblies as a function of burnup.To ensure the proliferation resistance,the value of ²³⁵U enrichment is < 20%.The K_eff is calculated using Dragon 4.0.4 for a single fuel rod and the model developed to fuel assembly,while the whole core was calculated using Citation code.For a fuel burnup,the use of increased enrichment fuel in the IRIS core leads to high reserve of reactivity,which is compensated with an integral fuel burnable absorber.The self-shielding of boron is in an IRIS reactor fuel.The effect of increased enrichment to the burn-up rates,and burnable poison distribution on the reactor performance,are evaluated.The equipment used in traditional light water reactors is evaluated for designing a small unit IRIS reactor.     

Numerical and experimental investigation on the breast cancer tumour parameters by inverse heat transfer method using genetic algorithm and image processing

This study presents numerical and experimental investigation on breast cancer tumour parameters by inverse heat transfer method using genetic algorithm (GA) and image processing (IP) to determine the depth and rate of heat generation of a breast cancer tumour. To simulate the problem, using the energy equation in a cylinder including a heater, the surface temperature distribution was obtained. Then, the temperature surface of the cylinder was analysed by the GA in MATLAB software to determine the depth and rate of heat generation of heater. The validity of the numerical method was evaluated using the IP from a laboratory sample. A thermal heater was placed inside a cylinder and was covered by a tissue similar to the human body tissue. According to the obtained results, it was determined that the results of the laboratory sample and the numerical method were in agreement with each other. Finally, these steps were applied on the thermal image of a patient’s cancer breast to determine the depth and rate of heat generation of the breast tumour. It is shown that the average computational error between numerical and experimental results in this method to determine the depth of the tumour is about 8–10% and to determine the rate of tumour heat generation is about 0.01–1%.     

桥面板与覆层结合界面的干燥收缩诱导应力估算

采用三维非线性有限元分析方法评价与估算了桥面板与混凝七覆层间结合界面的干燥收缩诱导应力.并采用修正Fowler准则测算了桥面板与聚合物覆层间的热诱导应力.在评价覆层与面板问相对厚度to/ts的影响时,ts取常数200mm;在评价相对弹性模量Eo/Es的影响时,Es取常数,27.5GPa,并设定了3个Eo/Es比值,分别...     

Superelastic behavior of nanostructured Ti50Ni48Co2 shape memory alloy with cold rolling processing

Effects of cold rolling followed by annealing on microstructural evolution and superelastic properties of the Ti₅₀Ni₄₈Co₂ shape memory alloy were investigated. Results showed that during cold rolling, the alloy microstructure evolved through six basic stages including stress-induced martensite transformation and plastic deformation of martensite, deformation twinning, accumulation of dislocations along twin and variant boundaries in martensite, nanocrystallization, amorphization and reverse transformation of martensite to austenite. After annealing at 400 °C for 1 h, the amorphous phase formed in the cold-rolled specimens was completely crystallized and an entirely nanocrystalline structure was achieved. The value of stress level of the upper plateau in this nanocrystalline alloy was measured as high as 730 MPa which was significantly higher than that of the coarse-grained Ni₅₀Ti₅₀ and Ti₅₀Ni₄₈Co₂ alloys. Moreover, the nanocrystalline Ti₅₀Ni₄₈Co₂ alloy had a high damping capacity and considerable efficiency for energy storage.     

Identification of a class of time-variable linear systems via its output covariance function

The main concern of this paper is to determine the state-space representation of a class of linear time-variable, periodic system, such that when excited by stationary white noise it results in a random process with prescribed covariance function. It is shown that by using a proper transformation on the state covariance matrix of the system it is possible to find a new matrix which has periodicity properties and satisfies a periodic matrix Riceati differential equation; therefore, the time interval of interest, on which the matrix Riceati equation must be solved using previous approaches, will collapse into one period.     

A fully integrated high IP1dB CMOS SPDT switch using stacked transistors for 2.4 GHz TDD transceiver applications

A transmit/receive (T/R) switch is an essential module of every modern time division duplex (TDD) transceiver circuit. A T/R switch with high power handling capacity in CMOS process is difficult to design due to capacitive coupling of radio frequency signals to the substrate. This paper proposes a single-pole-double-throw (SPDT) T/R switch designed in a standard Silterra 130 nm CMOS process for high-power applications like RFID readers. The results reveal that, in 2.4 GHz ISM band, the proposed switch exhibits a very high input P1dB of 39 dBm with insertion loss of only 0.34 dB and isolation of 40 dB in transmit mode but 1.08 dB insertion loss and 30 dB isolation in receive mode. Stacked thick-oxide triple-well transistors, resistive body floating and negative control voltages are used to achieve such lucrative performance. Moreover, the chip size of the designed switch is only 0.034 mm² as bulky inductors and capacitors are avoided. The Monte-Carlo and corner analyses confirm that the performance of the switch is also quite stable and reliable.     

形变热处理制备的纳米晶NiTi形状记忆合金的超弹性行为（英文）

研究冷轧和后续退火形变热处理对Ni_(50)Ti_(50)形状记忆合金超弹性行为的影响。采用铜坩埚真空感应熔炼法制备样品。将成分均匀的样品进行热轧后在900°C退火,然后再进行冷轧,冷轧后样品的厚度有不同程度的减少,最大可达70%。透射电镜检测结果显示严重的冷轧导致Ni_(50)Ti_(50)合金中形成了纳米晶和非晶的复合显微组织。400°C下退火1 h后,冷轧样品中的非晶发生晶化形成纳米晶组织。随着冷轧变形量的增加,在超弹性实验中Ni_(50)Ti_(50)合金的弹性应变增加,变形量为70%的冷轧-退火样品其弹性应变为12%。此外,随着变形量的增加,应力诱导马氏体相变的临界应力提高。值得注意的是,70%变形量的冷轧-退火样品的阻尼容量值为28 J/cm3,明显高于商业NiTi合金。