基于学习进阶的初高中物理教学衔接——以“电路和电能”教学为例

随着《义务教育物理课程标准(2022年版)》颁布,提出加强初高中学段衔接问题。针对学生进入高中物理学习困难的问题,基于学习进阶理论,以“电路和电能”教学为例,从把握教学起点、设计认知冲突、指导思维方法三方面提出初高中物理教学的衔接策略,帮助教师把握课标、教材和学生水平,让物理教学实现有效衔接。

基于软开关技术的能量恢复电路及其检测

设计了一个适用于各类硬开关功率变换电路的电能恢复电路,兼容所有PWM控制电路,且非常简单,只需使用一个小线圈、两个辅助线圈和两个特定的二极管即可实现。通过功率因数校正电路PFC(Power Factor Correction Circuit)将该电路与SiC二极管进行比较。结果显示,新电路的能效高于SiC二极管。

Integrated circuit for single channel neural signal regeneration

Based on the 4-channel neural signal regeneration system which is realized by using discrete devices and successfully used for in-vivo experiments on rats and rabbits, a single channel neural signal regeneration integrated circuit （IC）is designed and realized in CSMC ＇ s 0. 6 μm CMOS （ complementary metal-oxide-semiconductor transistor ） technology. The IC consists of a neural signal detection circuit with an adjustable gain, a buffer, and a function electrical stimulation （FES） circuit. The neural signal regenerating IC occupies a die area of 1.42 mm × 1.34 mm. Under a dual supply voltage of ±2. 5 V, the DC power consumption is less than 10 mW. The on-wafer measurement results are as follows： the output resistor is 118 ml）, the 3 dB bandwidth is greater than 30 kHz, and the gain can be variable from 50 to 90 dB. The circuit is used for in-vivo experiments on the rat＇ s sciatic nerve as well as on the spinal cord with the cuff type electrode array and the twin-needle electrode. The neural signal is successfully regenerated both on a rat＇ s sciatic nerve bundle and on the spinal cord.

VUV Photoionization and Dissociation of Tyramine and Dopamine： the Joint Experimental and Theoretical Studies

Photon induced dissociation investigations of neutral tyramine and dopamine are carried out with synchrotron vacuum uRraviolet photoionization mass spectrometry and theoretical calculations. At low photon energy, only molecular ions are measured by virtue of nearthreshold photoionization. While increasing photon energy to 11.7 eV or more, four distinct fragment ions are obtained for tyramine and dopamine, respectively. Besides, the ionization energies of tyramine and dopamine are determined to be 7.984-0.05 and 7.674-0.05 eV by measuring the photoionization efficiency curves of corresponding molecular ions. With help of density function theory calculations, the detailed fragmentation pathways are established as well. These two molecular cations have similar aminoethyl group elimination pathways, CTHsO2＋ （m/z=124） and C7H8O＋ （m/z=108） are supposed to be generated by the McLafferty rearrangement via γ-hydrogen （7-H） shift inducing β-fission. And CH2NH2＋ is proposed to derive from the direct fission of C7-C8 bond. Besides, the McLafferty rearrangement and the C7-C8 bond fission are validated to be dominant dissociation pathways for tyramine and dopamine cations.

High-Speed,Robust CMOS Dynamic Circuit Design

A novel circuit with a narrow pulse driving structure is proposed for enhancing the noise immunity and improving the performance of wide fan-in dynamic circuits. Also,an analytical mode that agrees well with simulations is presented for transistor sizing. Simulation results show that an improvement of up to 12% over the conventional technique at 1GHz is obtained with this circuit,which can run 1.6 times faster than the existing technique with the same noise immunity.

A novel low-voltage high precision current reference based on subthreshold MOSFETs

A novel topology low-voltage high precision current reference based on subthreshold Metal-Oxide-Semiconductor Field Effect Transistors （MOSFETs） is presented. The circuit achieves a temperature-independent reference current by a proper combination current of two first-order temperature-compensation current references, which exploit the temperature characteristics of integrated poly2 resistors and the 1- V transconductance characteristics of MOSFET operating in the subthreshold region. The circuit, designed with the 1 st silicon 0.35 μm standard CMOS logic process technology, exhibits a stable current of about 2.25 μA with much low temperature coefficient of 3 × 10^-4μA/℃ in the temperature range of-40-150 ℃ at 1 V supply voltage, and also achieves a better power supply rejection ratio （PSRR） over a broad frequency. The PSRR is about -78 dB at DC and remains -42 dB at the frequency higher than 10 MHz. The maximal process error is about 6,7% based on the Monte Carlo simulation. So it has good process compatibility.

Modeling and Controlling of an Active Power Filter Using Photovoltaic System with Reduced Energy Storage Capacitor

A novel three-phase active power filter （APF） circuit with photovoltaic （PV） system to improve the quality of service and to reduce the capacity of energy storage capacitor is presented. The energy balance concept and sampling technique were used to simplify the calculation algorithm for the required utility source current and to control the voltage of the energy storage capacitor. The feasibility was verified by using the Pspice simulations and experiments. When the APF mode was used during non-operational period, not only the utilization rate, power factor and power quality could be improved, but also the capacity of energy storage capacitor could sparing. As the results, the advantages of the APF circuit are simplicity of control circuits, low cost, and good transient response.

Solar-Powered Direct-Current Loads in Small Buildings

Traditional light bulbs （e.g., incandescent, fluorescent） use too much electricity, convert very little energy into light of sufficient quality and in their production use toxic contaminants. During the last few years, a new type of light source, LED （light emitting diode） bulb, has gained increasing popularity and its costs are set to plunge even further. LED bulbs offer many advantages over traditional sources, and they can be used as a direct replacement to existing lighting. This paper will use a spreadsheet-based analysis with hourly solar data supplied by Ecotect to show that, the efficiency of LED installations can be increased when used in conjunction with photovoltaic modules, as the two generate （and use） DC （direct-current） electricity, thereby eliminating intermediate-level losses in the electronic circuitry. If a storage battery is included, the solar panels generate electricity during the times when the occupants are not necessarily using the lighting, but the stored electricity can be used to power the lighting when the energy is required. The latest results demonstrate that, a slight reduction in the required floor area to be lit allows the solar-battery-LED system to be implemented in small buildings using a storage battery size that is within the range of present commercial devices.

A Novel Technology for Generation of Electricity and Cold by Using Energy Potential of Transmission Line＇s High Pressure Gas

The main objective of this paper is to develop a novel technology for combined generation of electricity and cold by using energy potential of transmission line＇s high pressure gas. For this purpose, the reduction of high pressure of the gas in gas distribution station instead of useless expansion throttling process is suggested to realize by adiabatic expansion, which is executed in a gas expanding turbine. Herewith, the gas distribution station is turned into energy and cold generating plant. Simultaneous operation of energy and cold generating plant is described. A method and appropriate formulas for determination of design characteristics of considered plant are suggested. A new method for reveres order of calculation and design of the cold store based on the use of expanded cold gas as cooling agent is developed. Calculations and analysis prove high energy efficiency of suggested technology, the wide use of which will provide significant production of cheap electricity and cold and as well as reduction of fossil fuel consumption.

Integrated Power Conversion for Multiple DC Voltage Sources and Its Power Quality

In a smart grid, electric loads are supplied by various DC （direct current） power sources, such as solar cells or batteries. On the other hand, traditional AC （alternating current） loads like a directly connected induction motors will also be used. In the circumstances, a smart power conversion unit is one of key components, which can integrate these DC or AC apparatus and trade power among them. Authors have developed an integrated power converter based on a well-known circuit topology of flying capacitor multilevel converter. This paper describes the detail of the circuit topology and its characteristics depending on designed parameters. The achieved power quality is also verified by simulation study.

Highly-compliant,conformal and stretchable microelectrode arrays

Most biological tissues are supple and elastic, while current electronic devices fabricated by semiconductors and metals are usually stiff and brittle. As a result, implanted electronic devices can irritate and damage surrounding tissues, causing immune reaction and scarring. In this work, we develop stretchable microelectrode arrays, with the development of a novel soft lithography technology, which are designed and fabricated with a polymer/stretchable metal/polymer sandwich structure. With the great deformability of stretch, compression, bend and twisting, while preserving electrical property, this technology overcomes the fundamental mismatch of mechanical properties between biological tissues and electronic devices, and provides highly-compliant, confonnal and stretchable bio-electronic interfaces. Here we also describe the following three applications of the stretchable electrode arrays： a. monitoring intracranial electroencephalography （EEG）; b. stimulating peripheral nerves to drive muscles; c. monitoring epicardial electrocardiography （ECG）. Stretchable microelectrode arrays create a promising field in biomedical applications for its better modulus match with biological tissues and robust mechanical and electrical properties. They allow for construction of electronic integrated circuits spread over on complex and dynamic curved surfaces, providing a much friendlier bio-electronic interface for diagnosis, treatment and in- telligent bio-control.

Alternative Solutions to Mitigate Problems due to Neutral Conductors Theft in MV （Medium Voltage） Power Distribution Systems

This paper aims at analyzing the impact of the neutral conductor absence at specific sections over the performance of the power distribution lines, and proposing alternative solutions to mitigate the problems caused by the neutral conductor theft. Simulations are made by the software lnterplan and show that the absence of neutral conductor at specific sections of power distribution lines may increase the neutral-to-ground voltages, which compromises the system＇s safety. The solution developed keeps the technical performance of the power distribution system at satisfactory levels, regarding the voltage profile, or, at least, close to the level before the neutral conductor＇s theft.

Measurement of Economic Power： An Engineering Approach

Business Directory defines economic power as ＂conditions of having sufficient productive resources at command that give the capacity to make and enforce economic decisions, such as allocation of resources and apportioning of goods and services＂. This qualitative definition may be sufficient for general discussions, but it does not offer any quantitative measurements for management and control. Is there a way to measure economic power for analysis and synthesis of economic systems in this 21st century？ This paper answers this question by introducing a set of quantitative terms from the field of electrical engineering, used in power measurement and control of electrical systems. Circuit theory concepts are introduced to show how the relationship between cash and cash flow in finance is analogous to that of electric charge and electric current and how education level, as economic potential, is analogous to electrical potential that causes current to flow in a circuit. An individual is identified as the basic cash flow source in the economy. Circuit models for an individual as well as a typical production facility are developed and demonstrated with an example. Equations for the measurement of economic power, losses, efficiency, and power factor are presented. It is shown that the individuals are the basic cash flow sources and producers of economic power.

Design Methods for Improving the Performance and Thermal Stability of Radar

The radar power supplies exhibit a complex electronics. The development of more and more compact systems leads to master the interaction between different parts of the power supply while reducing electronic circuits, magnetic and thermal couplings from the constitutive circuitry. The consideration of these phenomena is very difficult at the design of the power supply. This paper presents two complementary methods based first on a circuitry model for the quantification of heat sources and secondly on finite element model for heat diffusion. This approach can help a designer in the goal of improving the performances and thermal stability of radar tied to the supply circuit subset.

Control Power Source of PV-10 Piezoelectric Crystal Valve

Parameters of the power source used to control PV-10 piezoelectric crystal valve are following DC output voltage： 0 - 120 V, continuously controllable, linear enlargement factor of input direct current voltage： approximate 25 times, the accuracy of DC output voltage： ±5%, manual control and automatic control.

Impact of Sensor Technology for Line Protection Performance

The paper has presented the impact on the line protection performance with the introduction of MUs （merging units） in the process bus level. The paper begins with the introduction on modem digital substation structure and process bus. Then, the paper describes the performances of different sensors such as CTs （current transformers）, CVTs （capacitive voltage transformers）, FOCS （fiber optical current transducers） and FOVS （fiber optical voltage transducers）. With the use of above transducers together with MUs, the performance of distance protection function and line differential protection function have been investigated and presented. Finally, conclusions based on the study are presented in the paper.

Optimization design and analysis of Si-^(63)Ni betavoltaic battery

Among the various micro-powers being investigated, betavoltaic batteries are very attractive for numerous applications because of their advantages of high energy density, long life, strong anti-interference, and so on. Based on the basic principle of the betavoltaic effect, the current paper adopted the Monte Carlo N-Particle code to simulate the transport processes of β particles in semiconductor materials and to establish the calculation formulas for nuclear radiation-generated current, open circuit voltage, and so on. By discussing the effect of minority carrier diffusion length, doping concentration, and junction depth on the property of batteries, the present work concluded that the best parameters for batteries are the use of silicon and the radioisotope Ni-63, i.e., Ni-63 with a mass thickness of 1 mg/cm2, Na=1×1019 cm-3, Nd=3.16×1016 cm-3, junction area of 1 cm2, junction depth of 0.3 μm, and so on. Under these parameters the short-circuit current, open circuit voltage, output power, and conversion efficiency are 573.3 nA, 0.253 V, 99.85 nW, and 4.94%, respectively. Such parameters are valuable for micro-power fields, such as micro-electromechanical systems and pacemakers, among others.

Optimizing the component ratio of PEDOT:PSS by water rinse for high efficiency organic solar cells over 16.7%

For the state-of-the-art organic solar cells(OSCs),PEDOT:PSS is the most popularly used hole transport material for the conventional structure.However,it still suffers from several disadvantages,such as low conductivity and harm to ITO due to the acidic PSS.Herein,a simple method is introduced to enhance the conductivity and remove the additional PSS by water rinsing the PEDOT:PSS films.The photovoltaic devices based on the water rinsed PEDOT:PSS present a dramatic improvement in efficiency from 15.98%to 16.75%in comparison to that of the untreated counterparts.Systematic characterization and analysis reveal that although part of the PEDOT:PSS is washed away,it still leaves a smoother film and the ratio of PEDOT to PSS is higher than before in the remaining films.It can greatly improve the conductivity and reduce the damage to substrates.This study demonstrates that finely modifying the charge transport materials to improve conductivity and reduce defeats has great potential for boosting the efficiency of OSCs.

Sn precursor enables 12.4%efficient kesterite solar cell from DMSO solution with open circuit voltage deficit below 0.30 V

The limiting factor preventing further performance improvement of the kesterite(sulfide Cu2ZnSnS4(CZTS),selenide Cu2ZnSnS4(CZTSe),and their alloying Cu2Zn Sn(S,Se)4(CZTSSe))thin film solar cells is the large open-circuit voltage deficit(Voc,def)issue,which is 0.345 V for the current world record device with an efficiency of 12.6%.In this study,SnCl4 and Sn Cl2·2H2O were respectively used as tin precursor to investigate the Voc,def issue of dimethyl sulfoxide(DMSO)solution processed CZTSSe solar cells.Different complexations of tin compounds with thiourea(Tu)and DMSO resulted in different reaction pathways from the solution to the absorber material and thus dramatic differences in photovoltaic performance.The coordination of Sn^2+with Tu led to the formation of SnS,ZnS and Cu2S in the precursor film,which converted to selenides first and then fused to CZTSSe,resulting in poor film quality and device performance.The highest efficiency obtained from this film was 8.84%with a Voc,def of 0.391 V.The coordination of Sn4+with DMSO facilitated direct formation of CZTS phase in the precursor film which directly converted to CZTSSe during selenization,resulting in compositional uniform absorber and high device performance.A device with an active area efficiency of 12.2%and a Voc,def of 0.344 V was achieved from the Sn^4+solution processed absorber.Furthermore,CZTSSe/Cd S heterojunction heat treatment(JHT)significantly improved the performance of the Sn^4+device but had slightly negative effect on the Sn2+device.A champion CZTSSe solar cell with a total area efficiency of 12.4%(active area efficiency of 13.6%)and a low Voc,def of 0.297 V was achieved from the Sn^4+solution.Our results demonstrate the preformed uniform CZTSSe phase enabled by Sn4+precursor is the key for the highly efficient CZTSSe absorber.The lowest Voc,def and high efficiency achieved here shines new light on the future of CZTSSe solar cell.

Investigation of shunt solar cells’ currents based on equivalent circuit model

In view of the universality of the parallel connection of solar cells and their mismatch problem, in the present paper, we select two shunt solar cells (connected in parallel) as our research object, and use the equivalent one-diode circuit of the solar cell and the analysis of the two-body model. At first, the equations of current and voltage are deduced from the related electrical laws and the circuit diagram of the two solar cells connected in parallel. Then, according to the experimentally measured data of typical single-crystalline silicon solar cells (125 mm×125 mm), we select the appropriate simulation parameters. Following this, by using the photo-generated current, the shunt resistance, and the serial resistance of one of the shunt solar cells and the load resistance as independent variables, in turn, the changing characteristics of each branch current in the two shunt solar cells are numerically discussed and analyzed for these four cases for the first time. At the same time, we provide a simple physical explanation for the modeling results. Our analyses show that these parameters have different impacts on the internal currents of solar cells connected in parallel. These results provide a reference to solve the problem of connecting solar cells and to develop higher efficiency solar cells and systems. Meanwhile, the results will contribute to a better comprehension of the reasons for efficiency loss of solar cells and systems, and deepen the understanding of the electrical of solar cells behavior for high performance photovoltaic applications.