毛纺针梳机牵伸微调率与定量控制分析

通过对针梳机牵伸微调率的分析，揭示了毛纺针梳机定量控制的问题即出条重量偏差和重量不匀率较难控制，解决这一问题须从牵伸变换齿轮轮系着手。

Design of a Bandgap Reference with a Wide Supply Voltage Range

An on-chip voltage reference with a wide supply voltage range is required by some applications,especially that of power management （PM） controller chips applied to telecommunication, automotive, lighting equipment, etc., when high power supply voltage is needed. Accordingly,a new bandgap reference with a wide supply voltage range is proposed. Due to the improved structure,it features a high power supply rejection ratio （PSRR） and high temperature stability. In addition, an auxiliary micro-power reference is introduced to support the sleep mode of the PM chip and reduce its standby power consumption. The auxiliary reference provides bias currents in normal mode and a 1.28V reference voltage in sleep mode to replace the main reference and save power. Simulation results show that the reference provides a reference volt- age of 1.27V,which has a 3.5mV drift over the temperature range from -20 to 120~C and 56t^V deviation over a supply voltage range from 3 to 40V. The PSRR is higher than 100dB for frequency below 10kHz. The circuit was completed in 1.5tzm BCD （Bipolar-CMOS-DMOS） technology. The experimental results show that all main expectations are achieved.

Magnetic sensitivity technology based on microwave modulation of solid state spin system NV center

In view of the low resolution and accuracy of traditional magnetometer,a method of microwave frequency modulation technology based on nitrogen-vacancy(NV)center in diamond for magnetic detection was proposed.The magnetometer studied can reduce the frequency noise of system and improve the magnetic sensitivity by microwave frequency modulation.Firstly,ESR spectra by sweeping the microwave frequency was obtained.Further,the microwave frequency modulated was gained through the mixed high-frequency sinusoidal modulation signal generated by signal generator.In addition,the frequency through the lock-in amplifier was locked,and the signal which was proportional to the first derivative of the spectrum was obtained.The experimental results show that the sensitivity of magnetic field detection can reach 17.628 nT/Hz based on microwave frequency modulation technology.The method realizes high resolution and sensitivity for magnetic field detection.

Differential Space Frequency Mapping Schemes and Norm Criterion

This paper proposed four types of differential modulation to map the unitary code into the orthogonal frequency division multiplexing(OFDM) signal. The time-varying channel model is established and the norm of detection metric is deduced. The norm is the inherent interference of the time-varying channel, so it can be used as criterion to evaluate the performance of the mapping schemes. The simulation results agree with the analytic conclusion.

2-Harmonic Curves Isometrially Immersed in a Surface

In this paper,the author proves the necessary and sufficient condition for the existence of 2-harmonically and isometrically immersed curves in a 2-dimensinonal surface N∪→IE^3.

Adaptive Soft Frequency Reuse Scheme for In-building Dense Femtocell Networks

Femtocell networks have emerged as a key technology in residential, office building or hotspot deployments that can sig- nificantly fulfill high data demands in order to offioad indoor traffic from outdoor macro cells. However, as one of the major challenges, inter-femtocell interference gets worse in 3D in-building scenarios because of the presence of numerous interfering sources and then needs to be considered in the early network planning phase. The indoor network planning and optimization tool suite, Ranplan Small- cell~, makes accurate prediction of indoor wireless RF signal propagation possible to guide actual indoor femtocell deployments. In this paper, a new adaptive soft frequency reuse scheme in the dense femtocell networks is proposed, where multiple dense femtocells are classified into a number of groups according to the dominant interference strength to others, then the minimum subchannels with different frequency reuse factors for these groups are determined and transmit powers of the group- ing sub-channels are adaptively adjusted based on the strength to mitigate the mutual inter- ference. Simulation results show the proposed scheme yields great performance gains in terms of the spectrum efficiency relative to the legacy soft frequency reuse and universal fre- quency reuse.

Microwave Reflectometry on HL-2A Tokamak

One of the most important electron density diagnostics, microwave reflectometry, has been developed on many large and medium nuclear fusion devices in recent years . Not only the electron density profiles with high temporal and spatial resolutions, but also the profiles of plasma rotation and turbulence can be obtained with this diagnostic system.

Tunable and coherent nanosecond 7.2-12.2 μm mid-infrared generation based on difference frequency mixing in ZnGeP_2 crystal

A coherent mid-infrared laser source,which can be tuned from 7.2 μm to 12.2 μm based on the type-Ⅰ phase-matched difference frequency generation(DFG) in an uncoated ZnGeP2(ZGP) crystal,is reported.The two pump waves are from a type-Ⅱ phase-matched dual-wavelength KTP optical parametric oscillator(OPO) of which the signal and idler waves are tuned during 1.85-1.96 μm(extraordinary wave) and 2.5-2.33 μm(ordinary wave),respectively.The maximum energy of the generated mid-infrared laser is 10 μJ at 9.22 μm,corresponding to the peak power of 2.2 kW.

High harmonic exploring on different materials in dynamic atomic force microscopy

In atomic force microscopy(AFM), high-frequency components consisted in dynamic tip-sample interaction have been recently demonstrated as a promising technique for exploring more extensive material properties. Here we present an exploratory study of high harmonic atomic force microscopy by force-spectroscopy and high harmonic imaging. Since these components are very weak compared to the fundamental response, we firstly designed a high harmonic cantilever by tuning the second order flexural resonance frequency to an integer 6 times of its fundamental mode(i.e. ω_2=6ω_1). Moreover, it is verified that high harmonic can discern extra features than topographies on different samples with amplitude/frequency modulation(AM/FM) dynamic AFM mode. In AM mode, the first resonance amplitude and 6 th harmonic amplitude were discussed. The 6 th harmonic is more sensitive than the first order response. In FM mode, it is noted that the decaying rate of the 6 th harmonic frequency is approximately 6 multiples to the slope of the fundamental frequency shift when the tip approaches to the surface of sample. This non-destructive method was also adopted to investigate the local interlayer coupling and intercalation in the two-dimensional graphene films tentatively.

Frequency comb in a parametrically modulated micro-resonator

In this paper,we report the frequency comb response experimentally and analytically in a rhombic micro-resonator with parametrical modulation.When the electrostatically actuated rhombic micro-resonator is modulated axially by a low-frequency periodic excitation,a comb-like vibration response with few equidistant positioned fingers in the frequency domain is observed.The finger spacing of frequency comb response is exactly consistent with modulation frequency and the number and amplitude of the fingers can be tuned by modulation strength.A mixed frequency comb with extra comb fingers is further generated when the resonator is modulated simultaneously by two different low-frequency excitation signals.By adjusting the relation of the two modulation frequencies,unequal spacing frequency combs are achieved for the first time,which leads to a more flexible tunability of the comb spacing for different applications.Theoretical analysis based on the dynamic model well explains the corresponding observations.