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The increase of base current is the main damage effect of p-n-p bipolar junction transistors (BJTs) subjected to ionization radiation. The Gummel–Poon (G-P) model is widely used to describe the electrical performance of BJTs. For the purpose of simulating the ionization damages on bipolar circuit performance, this article develops a G-P SPICE model that incorporates the latest formula of excess base current. Then, this article reports the ionization damage effects on a p-n-p controlled common-emitter amplifier circuit that is a key unit in the bipolar integrated circuit. After $\gamma $ -ray exposures, both the output voltage of the common-emitter circuit and its relaxation time decrease. Two novel phenomena are observed for the ionization damages on the common-emitter circuit, i.e., the degradation of output voltage exhibiting time-dependent effects and sublinear dependence on dose. Moreover, this article proposes, from perspectives of SPICE simulation and circuit theory, the mechanisms behind the characteristics of degradation from ionization damage in the common-emitter circuit. The SPICE simulations provide a good fit to the experimental data for the response of output voltage of a 2N2907 p-n-p controlled common-emitter circuit to ionization damage with a dose up to 2000 Gy(SiO2). Also, this article presents two applications of the new SPICE model in quantitatively describing the ionization damages on basic circuits, including crosstalk-related degradation and process-related statistical distribution of degradation.

The metal-oxide-silicon (MOS)-controlled thyristor (MCT) has been characterized by MOS-gating, high-current-rise rate, and high blocking capabilities. The anode-short MCT (AS-MCT) is distinguished from conventional MCT by an anode-short structure, which forms an extracting path for electron current at the gate ground and develops a normally-off characteristic. As a composite structure made of MOS and bipolar junction transistors, AS-MCT is susceptible to displacement damage (DD). For the first time, this article reports the DD effects on AS-MCT with the fast neutron flux in the range of $3.1 \times 10^{9}$ – $5.5 \times 10^{13}\,\,\text {cm}^{-2}$ . Both the transfer and forward conductive characteristics are degraded subsequent to neutron exposures. When the neutron flux surpasses a critical value, the function failure of AS-MCT occurs, i.e., the AS-MCT cannot be latched up and enter into the thyristor-like conductivity mode, and, instead, remains in the insulated gate bipolar transistor-like conductivity mode. For the forward blocking characteristics (open gate), both the anode leakage current and forward blocking voltage increase subsequent to neutron exposures. To note, a novel phenomenon is observed for AS-MCT following neutron exposures, i.e., the forward current–voltage curve exhibiting “double snap-back effect.” This article proposes, from a device physics perspective, the mechanism behind the characteristics of degradation from DD in AS-MCT. The dependencies of the key parameters on neutron flux and the failure neutron flux are analytically modeled. Our models provide an excellent fit to the experimental data of the XND1 AS-MCT subjected to fission neutrons.

Drift bipolar junction transistors (BJTs), characterized by a graded doping profile in the base region, are susceptible to the recombination in both the base and emitter–base depletion regions when they are damaged by atomic displacement, leading to the gain degradation. The previous model of the gain degradation of BJTs (i.e., Messenger–Spratt model) adopts the assumptions of the neutral base and ideal depletion, which are not valid for the drift BJTs. A drift BJT has an extra build-in electric field which breaks the neutral base condition, and the excess recombination rate is reduced and depends on the drift parameters. Furthermore, the nonideal depletion effects can suppress the excess recombination in the junction region, which will also reduce the susceptibility of the displacement damage (DD). This paper presents a physics-based improvement of the previous model and provides a much better fit to the experimental data of the 3CK3B drift BJTs subjected to deuterium–tritium 14-MeV neutron irradiation. The new model also suggests that the ideal factor of excess base current induced by DD approaches to 1.33 for the BJT technologies with narrow base or operated under low bias conditions.

Through the analysis for the current urban road network and the urban traffic control schemes, establish the model of the average of vehicle up-time in road network. Then, by use for reference thinking of natural selection of genetic algorithm improved the minimum value problem of particle swarm optimization algorithm. Hereafter, the model was optimized by the improved particle swarm optimization, and the solving result when the model is the minimum value is the optimal timing scheme of each intersection within the region. Finally, collecting traffic information through the regional road network consisting of four-way intersection near the school, and this data as the basis to build a four-way intersection area network in VISSIM5.20 soitware, and making simulation experiment of the comparison of the optimization model and traditional timing scheme by MATLAB software. The results of the analysis according to the simulation experimental shows that the average running time of all vehicle of region increase about 24.1 percent, and the average delay time of all Intersection reduce about 27.4 percent. In a certain extent, Improve the efficiency of regional transit traffic and ease urban traffic pressure, and has some applicability.

Rationale:Giant cell tumor (GCT) is a locally aggressive bone tumor with a high recurrence rate if not completely excised. And reconstructive hip surgery using an artificial prosthesis in a young active patient is controversial because of problems related to the durability of the artificial