A study of strong photoluminescence of SiOx : H films

We have examined photoluminescence (PL), IR absorption and Raman spectra of a series of hydrogenated amorphous silicon oxide (a-SiOx:H, (0 < x < 2)) films fabricated by plasma enhanced chemical vapor deposition (PECVD). Two strong luminescence bands were observed at room temperature, one is a broad envelope comprising a main peak around 670 nm and a shoulder at 835 nm, and the other, peaked around 850 nm; is found only after being annealed up to 1170 degrees C in N-2 environment. In conjunction with IR and Raman spectra, the origins of the two luminescent bands and their annealing behaviors are discussed on the basis of quantum confinement effects.

Performing Fast Addition and Multiplication by Transferring Single Electrons

This paper proposes novel fast addition and multiplication circuits that are based on non-binary redundant number systems and single electron (SE) devices. The circuits consist of MOSFET-based single-electron (SE) turnstiles. We use the number of electrons to represent discrete multiple-valued logic states and we finish arithmetic operations by controlling the number of electrons transferred. We construct a compact PD2,3 adder and a 12x12bit multiplier using the PD2,3 adder. The speed of the adder can be as high as 600MHz with 400nW power dissipation. The speed of the adder is regardless of its operand length. The proposed circuits have much smaller transistors than conventional circuits.

Nanoelectronic Circuit Architectures Based on Single-Electron Turnstiles

Single-electron devices (SEDs) have ultra-low power dissipation and high integration density, which make them promising candidates as basic circuit elements of the next generation VLSI circuits. In this paper, we propose two novel circuit single-electron architectures: the single-electron simulated annealing algorithm (SAA) circuit and the single-electron cellular neural network (CNN). We used the MOSFET-based single-electron turnstile [1] as the basic circuit element. The SAA circuit consists of the voltage-controlled single-electron random number generator [2] and the single-electron multiple-valued memories (SEMVs) [3]. The random-number generation and variable variations in SAA are easily achieved by transferring electrons using the single-electron turnstile. The CNN circuit used the floating-gate single-electron turnstile as the neural synapses, and the number of electrons is used to represent the cells states. These novel circuits are promising in future nanoscale integrated circuits.

A Novel Architecture of Vision Chip for Fast Traffic Lane Detection and FPGA Implementation

This paper presents a novel architecture of vision chip for fast traffic lane detection (FTLD). The architecture consists of a 32*32 SIMD processing element (PE) array processor and a dual-core RISC processor. The PE array processor performs low-level pixel-parallel image processing at high speed and outputs image features for high-level image processing without I/O bottleneck. The dual-core processor carries out high-level image processing. A parallel fast lane detection algorithm for this architecture is developed. The FPGA system with a CMOS image sensor is used to implement the architecture. Experiment results show that the system can perform the fast traffic lane detection at 50fps rate. It is much faster than previous works and has good robustness that can operate in various intensity of light. The novel architecture of vision chip is able to meet the demand of real-time lane departure warning system.

A Novel CMOS Color Pixel for Vision Chips

This paper presents a novel CMOS color pixel with a 2D metal-grating structure for real-time vision chips. It consists of an N-well/P-substrate diode without salicide and 2D metal-grating layers on the diode. The periods of the 2D metal structure are controlled to realize color filtering. We implemented sixteen kinds of the pixels with the different metal-grating structures in a standard 0.18 mu m CMOS process. The measured results demonstrate that the N-well/P-substrate diode without salicide and with the 2D metal-grating structures can serve as the high speed RGB color active pixel sensor for real-time vision chips well.

Experimental study on flow characters of CH3CCl2F hydrate slurry

The flow behaviors of CH3CCl2F hydrate slurry with volume concentration of 10-70% were studied in a new built flow loop with a diameter of 42.0 mm and length of 30.0 m. Morphologies of the fluids from slurrylike hydrates to slushlike hydrates with increasing of hydrate volume concentration in pipeline were observed. Pressure drops in pipeline also were studied and an exceptional pressure transition zone with hydrate volume concentration between 30% and 40% was found for the first time, which can be used as a notation to judge if the pipeline runs safely or not. Fanning friction factors of the hydrate slurries with all hydrate contents tend to constants between 0.38 and 0.5, which depend on the volume concentration in slurries, when the velocity reaches 1.5 m/s. A simple relation to estimate the pressure drop of hydrate slurry in pipeline was presented and verified. Experimental results were compared to the estimated results, which showed a good agreement. 

苯乙烯辐射乳液聚合

用膨胀计连续记录法测定了St辐射乳液聚合的转化率～时间曲线，并由此得到包括在临界胶束浓度以下和在低的单体浓度下在内的各种反应条件下的聚合反应速度。发现其聚合速率与各因素之间的依赖关系，为：R_p∝l~(0.4)，R_p∝E~(0.7～0.9)。测得反应活化能为6.1 ～ 8千卡／摩尔。实验结果还表明：恒定速率部分延续到转化率70％左右，粒子数随温度的增加而减少，水与单体体积比对聚合速率以及分子量与转化率的关系都有影响。在监界胶束浓度以下进行聚合所获得的胶乳的粒子直径分布是单分散的，而聚合速率仍然符合一般情况下的聚合速率与乳化剂浓度的关系。这些实验结果在某些方面与Smith-Ewart理论相符，在某些方面不符。目前，大多数研究者都认为：St乳液聚合的成核方式是胶束成核。对于增长反应的位置有分歧。一派认为是在粒子内；另一派认为是在肥皂分子吸附层与单体一聚合物粒子表面之间为了探讨增长反应的位置究竟是在哪方。同时澄清国际上两个学派在这个问题上的争论，我们用电镜，光散射（未去单体），肥皂滴定三种测定方法同时测定了St乳液聚合恒定速率部分胶乳粒子的增长情况。测定结果表明：由于聚合物胶乳中溶胀有单体造成了用不同方法测定 将得出不同的结果。所以，两个学派仅从电镜或肥皂滴定的测定结果都不能证实增长反应发生的位置。根据我们的上述实验结果，我们设想其聚合反应机理如下：i)成核是既有水相成核又有胶束成核。ii)增长反应是在具有“核－壳“结构的单体－聚合物乳胶粒表面与肥皂分子吸附层之间进行的即在“壳“中进行的。我们从热力学和静电排斥的观点出发进行了理论分析。结果表明这种增长反应的模型是合理的。 我们所设想的反应机理能满意地解释实验结果，并在实验上得到证实。在所设想的反应机理的基础上，建立了动学模型计算公式，其第Ⅱ阶段总转化率表达式如下：X = AX_m + BX_w其中：X_m = k/2N_(mc) (t-t_(mcl)) + X_(mcl) X_w = k/2N_(wc) (t-t_(wcl)) + X_(wcl) A和B分别为胶束成核和水相成核分数用我们的动力学模型计算公式计算出的结果与实验结果相符合。这表明我们所设想的反应机理及动力学模型计算公式是合理的。根据我们所设想的反应机理，在临界胶束浓度以下只有一种成核方式。因此可以预期到利用在临界胶束浓度以下进行St辐射乳液聚合，将可以合成出用化学法无乳乳液聚合所不能获得的稳定，单分散、高固体含量、粒子直径较小的胶乳。实验结果表明，利用这种聚合方法确实可以合成出这种胶乳。用此法合成出的胶乳粒子直径一般在600A ～ 4000A范围内。通过改变聚合条件可以控制所获得的胶乳粒子直径。在实验所使用的聚合条件范围内得到一个胶乳粒子直径与聚合条件的关系式：logD = 0.28 [log ([M])/E~(2.14)I~(0.5) + 0.143T] + 2.03。我们还考察了St辐射无乳乳聚合，发现聚合速率与I成0.5次方关系，活化能为7.5千卡／摩尔，水与单体体积比对聚合速率胶乳稳定性影响很大。产物分子量在10~4 ～ 10~5范围内，聚合物胶乳的分子量分布比用化学法和有乳化剂存在下的辐射法所获得的要窄些。实验结果表明在合适的聚合条件下，可以获得单分散、干净的胶乳，其聚合规律类似于化学法的。

Strong visible photoluminescence from amorphous silicon grains in a-SiOx:H films

Two strong luminescence bands were observed from a-SiOx:H in the spectral range of 550-900 nm at room temperature. One is a main broad peak which blueshifts with oxygen content and the other is a shoulder fixed at about 835 nm. In conjunction with TR and micro-Raman spectra, we have proposed that the main band may originate from the amorphous silicon grains embedded in SiOx network, while the shoulder might be due to some defects induced by excess-silicon in these films. (C) 1997 Elsevier Science Ltd.