Design strategy and development of spherical silicon solar cell with semi-concentration reflector system

Structural and economical merits of a spherical silicon solar cell with semi-concentration reflector system have been discussed. The roles of the reflector system have been clarified; the reflector improves short-circuit current density and also open-circuit voltage by 4–6 times concentration to make a light irradiation area comparable to a p–n junction area. We have theoretically demonstrated that the spherical Si solar cell with semi-concentration reflector system can realize a performance comparable to that of conventional Si solar cells, with less amount of silicon material use.     

An evaluation method of the fluctuation characteristics of photovoltaic systems by using frequency analysis

Short-time fluctuations in solar irradiance will become an important issue with regard to future embedded photovoltaic (PV) systems. However, when PV systems are intensively installed, fluctuation of total output in clustered PV systems is not remarkable because there is the smoothing effect of irradiance in certain areas. In this paper, a new estimation method of irradiance fluctuation, which is based on the combination of the Fourier transform and the wavelet transform methods, is described.     

Photovoltaic characteristics of phosphorus-doped amorphous carbon films grown by r.f. plasma-enhanced CVD

The phosphorus-doped amorphous carbon (n-C:P) films were grown by r.f. power-assisted plasma-enhanced chemical vapor deposition at room temperature using solid phosphorus target. The influence of phosphorus doping on material properties of n-C:P based on the results of simultaneous characterization are reported. Moreover, the solar cell properties such as series resistance, short circuit current density (J_sc), open circuit current voltage (V_oc), fill factor (FF) and conversion efficiency (η) along with the spectral response are reported for the fabricated carbon based n-C:P/p-Si heterojunction solar cell were measured by standard measurement technique. The cells performances have been given in the dark I–V rectifying curve and I–V working curve under illumination when exposed to AM 1.5 illumination condition (100 mW/cm², 25 °C). The maximum of V_oc and J_sc for the cells are observed to be approximately 236 V and 7.34 mA/cm², respectively for the n-C:P/p-Si cell grown at lower r.f. power of 100 W. The highest η and FF were found to be approximately 0.84% and 49%, respectively. We have observed the rectifying nature of the heterojunction structures is due to the nature of n-C:P films.     

Photoactive Electro-Controlled Visual Perception Memory for Emulating Synaptic Metaplasticity and Hebbian Learning

In bionic technology, it has become an innovative process imitating the functionality and structuralism of human biological systems to exploit advanced artificial intelligent machines. Bionics plays a significant role in environmental protection, especially for its low energy loss. By fusing the concept of receptor-like sensing component and synapse-like memory, the photoactive electro-controlled optical sensory memory (PE-SM) is proposed and realized in a single device, which endows a simple methodology of reducing power consumption by photoactive electro-control. The PE-SM is the system built with the stacked atomically thick materials, in which rhenium diselenide serves as a robust photosensor, hexagonal boron nitride serves as a tunneling dielectric, and graphene serves as a charge-storage layer. With the features of the PE-SM, it performs synaptic metaplasticities under optical spikes. In addition, a simulated spiking neural network composed of 24 × 24 PE-SMs is further presented in an unsupervised machine learning environment, performing image recognition via the Hebbian rule. The PE-SM not only improves the neuromorphic computing efficiency but also simplifies the circuit-size structure. Eventually, the concept of photoactive electro-control can extend to other photosensitive 2D materials and provide a new approach of constructing either visual perception memory or photonic synaptic devices.     

中国充电器标准化带来的变化

中国政府率先开始了手机充电器的标准化,其目的是让用户更换手机终端后可继续使用原来的充电器,从而通过削减废弃物达到保护环境的目的。     

Role of mitochondria in the switch mechanism of the cell death mode from apoptosis to necrosis--studies on rho0 cells

Detailed mechanisms of the switch of the cell death mode from apoptosis to necrosis remain to be solved, although the intracellular level of ATP and that of free radicals have been postulated to be the major factors involved in the mechanisms. In the present study menadione (MEN)-induced cell injury processes were studied using rho0 cells derived from human osteosarcoma 143B cells and parental rho+ cells co-treated with inhibitors of electron transfer chain of mitochondria or oligomycin, an inhibitor of ATP synthesis. Treatment of rho+ cells with 100 microM MEN induced apoptosis, which reached the maximum at 6 h, and was followed by an abrupt decrease thereafter, while necrotic cells (NC) increased continuously when they were judged by Annexin V and PI double staining. On the other hand, MEN induced apoptotic and necrotic changes much faster in rho0 cells compared to rho+ cells. The frequency to find apoptotic cells (AP) in the former cells was distinctly smaller than that to find NC judged by Annexin V and PI double staining. Electron microscopically, a major population of rho0 cells treated with MEN for 6 h consisted of intermediate cells, and a small number of AP co-existed. At 9 h of the treatment intermediate cells were exclusively seen, and AP were hardly detected. When parental rho+ cells were treated with MEN in the presence of oligomycin or oligomycin plus antimycin A both apoptotic and necrotic changes of the cells were distinctly accelerated. The intracellular level of superoxide in rho0 cells continuously increased after the MEN treatment, whereas that of ATP remained distinctly low before and after the MEN treatment compared to that in rho+ cells. These data suggest that the intracellular level of superoxide may be a key factor controlling the switch from apoptosis to necrosis.     

Transient phenomena of space charge distributions in polypropylene laminated paper

In a multilayer insulator made of two or more materials with different dielectric constants and conductivities, internal space change accumulates at their interfaces. If the local field is increased by the accumulated charge, the electric durability of the insulator should be decreased. In this paper, we describe the space charge accumulation measured when oil-impregnated PPLP (polypropylene laminated paper), which consists of three layers, kraft paper, polypropylene (PP), and kraft paper, was subjected to a strong dc electric field. The experimental results suggest that internal space charge accumulates at both surfaces of a PP layer and that the electric field in the kraft paper layers disappears. © 1998 Scripta Technica, Electr Eng Jpn, 124(1): 1–6, 1998     

Detection and Quantitation of Left-to-Right Shunts from Radionuclide Angiocardiography Using the Homomorphic Deconvolution Technique

The homomorphic filtering method is described for the detection and quantitation of left-to-right shunts from radionuclide angiocardiography. First, the method is investigated theoreticatly and numerically using a realistic model with systemic recirculation. It is demonstrated that even in a noisy situation the shunt flow fraction can be relatively well estimated, if only the characteristics of the fiters used are suitable. Second, the method is applied to real data, i.e., the pulmonary time-activity curves from radionucUde anglocardiography. The presence or absence of a left-to-right shunt is determined using the ratio AT/MTT. The pulmonary-to-systemic flow ratios calculated from the areas of the two decomposed curves are compared with those from oximetry at cardiac catheterization. Good agreement between the Qp/Qs ratios calculated by oximetry and radionucUide angiocardiography is obtained.     

Capillary gas-liquid chromatographic separation of oxo and oxo-hydroxy bile acid isomers of theallo and normal series

Capillary gas-liquid chromatographic separation was studied for 60 oxo and oxo-hydroxy bile acids of theallo (5α-H, A/B-trans) and normal (5β-H, A/B-cis) series, which differ from one another in the number, position, and configuration of oxo and hydroxy groups at positions C−3, C−4, C−6, C−7, and/or C−12. Good separation of the isomers was achieved by the use of an aluminum-clad fused-silica capillary column coated with bonded and cross-linked methyl polysiloxane.