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Recently, digital lock-in amplifiers (DLIAs) have been widely used in scientific research field for measuring weak signals. The method of implementing a DLIA hardware (like field programmable gate array) from the high-level specifications (such as C or C++) is required for software engineers. High-level synthesis (HLS) tool enables the realization of hardware design from high-level specifications automatically. The implementation of the DLIA by HLS is introduced in detail in this paper. The simulation results verify the feasibility of the implementation of the DLIA by HLS.

Light scattering is an important tool for gathering information about the structure and origin of atmospheric aerosols. We build a polarized scanning nephelometer to measure the properties of aerosol particles. However, the accuracy of the backward-scattered light measurements is limited by stray forward-scattered light reflected back into the collection optics. We briefly analyze this stray light. A new form of light trap with multiple hollow cones is introduced to suppress backward-scattered stray light. To evaluate the effect of the light trap on suppressing stray light for our nephelometer, a simulation model with and without the light trap was analyzed. Our results show that without the light trap, the percentage of backward-scattered stray light can be more than 50% for some kinds of particles. With the light trap with multiple hollow cones, the percentage of stray light with a backward-scattered angle can be less than 0.7%, which remains stable over different angles. Our results indicate that this structure could be particularly suitable for a light trap with a very large aperture but limited space.

In this paper, we propose channel and constraint compensation mechanism applied in Generative Adversarial Networks (GANs) to help distribution fitting and improve the visual quality of generated samples. The proposed channel compensation focuses on specific feature-related regions by weighting the channel of conv-layer feature maps, so specific feature modes of data distribution can be compensated and irrelevant features can also be decayed. By combining the Jensen-Shannon (JS) divergence and Wasserstein distance (WD) into a well-designed objective function, the constraint compensation can impose more useful constraints upon the generator to diversify the estimated density in capturing multi-modes. Extensive experiments are conducted on synthetic 2D data and real-world datasets (CIFAR-10, STL-10, CelaBa). The qualitative and quantitative comparisons against baselines demonstrate the effectiveness and superiority of our method.

Electrostatic force microscopy (EFM) including its derivative, Kelvin probe force microscopy, is widely used to investigate mesoscopic/nanoscopic conducting/semiconducting structures and electrical interactions. However, the resolution of EFM in ambient is largely limited by the applicable force-detection techniques. This work demonstrates that the lateral resolution of ambient EFM can be significantly improved using an intermittent contact method in conjunction with a resonant multi-frequency method for electrostatic force detection. A lateral resolution of sub-10 nm is obtained. The high-resolution contrast reflects the variation of surface potential in sample on a nanoscale. The mechanism, which is attributed to the decreased effective tip-sample distance, is elucidated by theoretical analysis. The newly developed technique can be easily integrated with existing techniques to herald the next generation of high-resolution probe techniques for various nanoscopic applications.

Er3+ doped PIN-PMN-PT (PIN-PMN-PT:Er3+) ceramic was synthesized by two step columbite precursor method. The structure and morphology of products are characterized by X-Ray diffraction (XRD) and scanning electron microscopy (SEM). It is demonstrated that the ceramic has the perovskite structure and grain size in the range of 3 μm–5 μm. Under excitation of 980 nm diode laser, obvious green and red emission bands were detected. According to the power dependent upconversion emission and energy level diagram, the possible energy transfer process was proposed. The optical temperature sensing properties were studied based on fluorescence intensity ratios (FIRs) from thermal coupled energy levels (TCELs) 2H11/2,4S3/2 and thermal linked red emission stark sublevels 4F9/2(1), 4F9/2(2) of Er3+ ions. respectively. The absolute sensitivity reaches maximum value of 0.0035 K−1 at 360 K corresponding to TCELs and 0.0025 K−1 at 327 K corresponding to stark sublevels in the measurement temperature range. The incident near-infrared laser induced heating effects were investigated. It is found that the pump power induced heating effect can be neglected in the range of 110 mW–460 mW. These results demonstrated that PIN-PMN-PT:Er3+ ceramic is a potential material for application in optical temperature sensing and this research pave the way for further developing ceramic based dual-mode FIR thermometry technique.

This paper presents an output-capacitorless adaptively biased (AB) low-dropout regulator (LDO) with stable behavior in 0–25 mA load range. The enhanced multipath nested Miller compensation (EMNMC) with embedded feedforward path and Q-reduction compensation technique are proposed, to achieve high loop gain and wide bandwidth. A symmetrically matched current-voltage mirror (SMCVM) is applied to implement the AB scheme, enabling accurate load current sensing and robust operation of the LDO during full load range. The proposed LDO has been designed in a 0.13-μm CMOS technology. Simulation results verify that the proposed LDO works stably under 0~25 mA loading current and 0~50 pF loading capacitance. It has a maximum current efficiency of 99.17% and a maximum unity-gain frequency (UGF) of 132 MHz. The extension of UGF also magnificently contributes to improvement of power-supply rejection (PSR).

A new circuit topology for pulsed time-of-flight (TOF) laser radar/range-finder receivers to achieve high sensitivity, wide dynamic range and low walk error is presented in this paper. The proposed topology adopts an adaptive structure as pre-amplifier which can work as a trans-impedance amplifier (TIA) or a charge-sensitive amplifier (CSA) depending on the current intensity received by the photodetector. With the help of the adaptive preamplifier, both the dynamic range and the sensitivity can be improved. In addition, a high-accuracy timing discrimination scheme based on converting the incoming unipolar pulse to a bipolar pulse is used to improve the amplitude-dependent timing walk error. Based on the proposed topology, a receiver channel is implemented with a standard 130nm CMOS technology and simulated in Spectre. The CSA and TIA in the receiver channel can share the same core amplifier so that the area and power efficiency are optimized. Simulation results show that the receiver channel achieves an RMS input-referred noise current of 39nA and a timing walk error of ±37ps (±5.6mm in distance) within the wide dynamic range of 1:100000 (100dB), and maximum walk error of ±19mm over the temperature range of −40°C to + 60°C.

The chip-to-board model is important for predicting the electromagnetic emission (EME) of an electronic system and checking whether it fulfills the emission standards at early design cycle. This paper proposes to build the chip-to-board model through directly measuring the chip-to-board transmission ratio with embedded circuit. The embedded circuit does not cause the modification the on-chip power distribution network. Only one signal pin is added to the chip. It preserves the original physical structure of the chip and package in a maximal way. The measurement method is verified through transistor level simulations and is demonstrated with a test chip. Using the measured transmission ratio, one can build a chip-to-board model with improved accuracy, especially in the high frequency range, for the EME simulation of electronic system.

This paper presents a low-power All-MOSFET voltage reference implemented on a 0.18-μm standard CMOS technology. In order to improve the temperature coefficient (TC) of voltage reference, a TC compensation technique based on controlling bulk voltage is proposed. The proposed voltage reference achieves a TC of 13 ppm/°C from −40 °C to 125 °C while dissipating a supply current of 70 nA in normal temperature. The line regulation is 0.02%/V when the supply voltage varies from 1.3 V to 2.1 V, and the power supply rejection ratio (PSRR) at 100Hz is 74 dB due to the cascode current mirror. Moreover, the current mirror can be reconfigured easily so that the output voltage can be trimmed in this design.

This Letter introduces a weakly supervised method for human action localisation, dubbed Two-stream Action Activation Network (TAAN). In order to generate both action category predictions and temporal location predictions only by video-level annotations, TAAN firstly utilises class response variance to select representative segments as video-level expressions. Then under the supervision of video-level annotations, these expressions are used to train a classification network. Next, temporal class activation maps (T-CAMs) are generated based on the classification response, and finally temporal level predictions are given according to T-CAMs. In addition, the proposed method fuses two-steam predictions in a simple but effective way to further improve the precision of the predictions. Evaluations on THUMOS 2014 dataset show TAAN outperforms state-of-the-art weakly supervised methods.

Upconversion nanoparticles (UCNPs) possess great potential for application in fluorescence imaging. Here, the high crystalline Gd2O3:Yb3+/Tm3+ UCNPs with the average diameter of 7.18 nm were fabricated by laser ablation in liquid (LAL). Under excitation at 980 nm, visible blue fluorescence of the LAL-derived Gd2O3:Yb3+/Tm3+ UCNPs is obtained and can be used for live cells imaging. Meanwhile, more efficient near-infrared (NIR) emission (∼800 nm) than the visible fluorescence is observed. The excitation and emission of Gd2O3:Yb3+/Tm3+ UCNPs are both within the “optical transmission window” of biological tissue, capable of great potential for deep tissues imaging.

A delta-sigma $(\Delta\Sigma)$ phase locked loop (PLL) transmitter with an efficient modulation bandwidth calibration technique is proposed in this paper. With the proposed technique, the digital-analog mismatch between digital pre-emphasis filter and PLL is calibrated. The loop filter $RC$ variation is tracked in the first place, and then the variation of the loop gain is calibrated by sensing the magnitude differences of the modulator between DC and ten times of the loop bandwidth. The proposed transmitter has been implemented in 0.18- $\mu{\rm m}$ CMOS technology for GSM/GPRS application. Measurement results show that the maximum RMS phase error of the proposed transmitter is 0.8 $^{\circ}$ . In addition, the measured calibration accuracies for $RC$ and loop gain variations are 0.5% and 0.8%, respectively. By reusing the PLL locking time, 18- $\mu{\rm s}$ calibration time is achieved. Moreover, most parts of the calibration circuitries can be shared with the receiver chain, reducing the circuit complexity overhead.

Manipulation of upconversion (UC) emission is of particular importance for multiplexed bioimaging. Here, we precisely manipulate the UC color output by utilizing the phonon-assisted energy back transfer (EBT) process in ultra-small (sub-10 nm) Gd2O3:Yb(3+)/Er(3+) UC nanoparticles (UCNPs). We synthesized the Gd2O3:Yb(3+)/Er(3+) UCNPs by adopting the laser ablation in liquid (LAL) technique. The synthesized Gd2O3:Yb(3+)/Er(3+) UCNPs are small spherical and monoclinic structures. Continuous color-tunable (from green to red) UC fluorescence emission is achieved by increasing the concentration of Yb(3+) ions from 0 to 15 mol%. A phonon-assisted energy back transfer (EBT) process from Er(3+) ((4)S3/2 → (4)I13/2) to nearby Yb(3+) ((2)F7/2 → (2)F5/2), which can significantly enhance red emission at 672 nm and decrease green emission, is responsible for the color-tunable UC emission by increasing the Yb(3+) concentration in Gd2O3:Yb(3+)/Er(3+) UC nanoparticles.

A new transceiver RFIC for China Geo-Radio Standard is proposed in this paper. It includes all necessary RF blocks to achieve the geo functionality and is implemented in a 0.13-μm RFCMOS technology, with a chip area of 3 mm∗3.4 mm. The power supply voltage for the transceiver is 1.8 V, and the measured maximum output power is 4.4 dBm. The noise figure of the receiver is measured to be 1 dB with external high-performance low-noise amplifier (LNA), and the measured EVM of the transmitter under maximum output power is 2.48%. Measurement results verified that the proposed design is very suitable for the China Geo-Radio Standard.

Distributed arithmetic (DA) algorithm is widely used for finite impulse response (FIR) filter implementation. In the beginning, DA was proposed as sequential DA (SDA), and then was extended to parallel DA (PDA) for higher throughput. This paper presents a novel PDA FIR filter architecture based on 4:2 compressors which can be mapped on Xilinx FPGAs efficiently. On average, our proposed FIR architectures achieve 17.5% reduction in resource usage and 20.7% improvement in performance compared to the state-of-the-art PDA FIR filter. Also, on average, there is 57.9% reduction in resource usage and 23.0% improvement in performance compared to PDA FIR filters generated by Xilinx Coregen.

An improved Nauta transconductor, with output resistance for differential-mode output signals insensitive to process and tuning voltage variations, is presented in this paper. Comparing with the classical Nauta transconductor, the proposed transconductor introduces 4 auxiliary inverters only. It can increase the differential-mode output resistance, and keep the common-mode output resistance nearly no changed at the same time. The proposed transconductor has been implemented in a 7th-order transconductance-C (gm-C) band-pass filter (BPF) in a standard 0.18-μm CMOS technology. The proposed filter has achieved a bandwidth of 20 MHz under a 15-MHz center frequency. Monte Carlo simulation results show that with the same tuning voltage range, the gain deviation of the filter with proposed transconductors is reduced 4.4 dB comparing with the counterpart based on classical Nauta transconductors, and the sensitivity of the quality (Q) factor of filter poles to tuning voltage is also significantly reduced. Measurement results show that the pass-band ripple of the proposed filter is reduced 1 dB, and the stop-band attenuation is reduced 8 dB at 30 MHz.

In this paper, an approach to synthesize compressor trees in High-level Synthesis (HLS) for FPGAs is proposed. Our approach utilizes the bit-level information to improve the compressor tree synthesis. To obtain the bit-level information targeting compressor tree synthesis, a modified bitmask analysis technique based on prior work is proposed. A series of experimental results show that, compared to the existing heuristic, the average reductions of area and delay are 22.96% and 7.05%. The reductions increase to 29.97% and 9.07% respectively, when the carry chains in FPGAs are utilized to implement the compressor trees.

This paper considers the relationship between the static gate delay and the supply voltage of the digital integrated circuit. An empirical equation with physical implication is proposed for calculating the static gate delay. The expression of the gate delay is very simple. It contains only three constants. The calculation includes only one subtraction step, one division step and one addition step. Transistor level simulations are performed to verify the equation. The model matches the experiment results precisely. It is valid for various technologies, gate types, and operation temperatures. The equation can be applied in EDA tools to simulate the timing of the circuit under the PVT variation and the electromagnetic interference.

Monoclinic Gd2O3:Eu(3+) nanoparticles (NPs) possess favorable magnetic and optical properties for biomedical application. However, how to obtain small enough NPs still remains a challenge. Here we combined the standard solid-state reaction with the laser ablation in liquids (LAL) technique to fabricate sub-10 nm monoclinic Gd2O3:Eu(3+) NPs and explained their formation mechanism. The obtained Gd2O3:Eu(3+) NPs exhibit bright red fluorescence emission and can be successfully used as fluorescence probe for cells imaging. In vitro and in vivo magnetic resonance imaging (MRI) studies show that the product can also serve as MRI good contrast agent. Then, we systematically investigated the nanotoxicity including cell viability, apoptosis in vitro, as well as the immunotoxicity and pharmacokinetics assays in vivo. This investigation provides a platform for the fabrication of ultrafine monoclinic Gd2O3:Eu(3+) NPs and evaluation of their efficiency and safety in preclinical application.

The micro–nano multiscale patterns of TiO 2 nanowires/carbon composite films with three different topographies are fabricated by combining photolithography, hydrothermal method and pulsed magnetic filtered cathodic vacuum arc deposition. The hemocompatibility of the micro–nano multiscale patterned composite films is assessed by the platelet adhesion test in vitro. Results show that the fewer platelets are adhered on the patterned TiO 2 nanowires/carbon composite films, indicating that the surface topography of the micro–nano multiscale patterns is a key factor in regulating the platelet behavior. The analysis demonstrates good correlation between the platelet coagulation behavior and the micro–nano multiscale effect, which leads to less effective surface contact area and less possibility of platelet variation. It suggests that the design of micro–nano multiscale patterns should be a promising technology to improve the hemocompatibility of implantable medical devices.

Dualmodal contrast agents of rare earth doped gadolinium oxide (Gd2O3) nanoparticles with high spatial resolution for magnetic resonance imaging (MRI) and high sensitivity for fluorescence imaging have attracted intensive attention in biomedical imaging. However, the rare earth doped nanoparticles mentioned above have been so far synthesized by the hydrothermal method, which is a bottom-up method, requiring high purity chemical reagents and relying on the availability of the respective precursors and strict reaction conditions. Here, we propose a facile and environmentally friendly top-down technique to synthesize the rare earth doped-Gd2O3 nanocrystals at an ambient environment. Using this approach, we synthesize a series of Tm3+, Tb3+, and Eu3+ doped-Gd2O3 nanoparticle colloids and observe strong blue, green, and red visible fluorescence from the as-synthesized nanoparticle colloids. Cell confocal microscope images show that these synthesized nanoparticle colloids are good fluorescence imaging contrast agents. Taking Gd2O3:Eu3+ nanoparticles as an example, we evaluate their performance in MRI in vitro and in vivo. These results indicate that the synthesized rare earth doped-Gd2O3 nanocrystals can be used as MRI and fluorescence imaging dualmodal contrast agents. The developed technique is expected to be a general, facile and environmentally friendly strategy towards synthesizing rare earth doped nanoparticles for biomedical applications.

A comparator-based current mode control buck-boost DC-DC converter with low transition noise full-wave current sensor is reported in this work. The proposed comparator-based current mode control method with on-time modulation eliminates the controller delay in constant on/off time period during load transient, which is adopted in a buck-boost DC-DC converter to achieve faster load transient responses. Benefited from the combination of SenseFET-based and filter-based current sensing, the proposed constructed current sensor is free from large spiking during state transition between high-side and low-side power transistor current sensing. Moreover, its dc accuracy will not drift due to the dc resistance (DCR) of the inductor as in the conventional filter-based inductor current sensor.

A shared-MSB sub-range delay-line-based window ADC capable of simultaneous quantization for digital control single-inductor-multiple-output (SIMO) DC-DC converter is proposed in this work. This ADC achieves the conversion by voltage-time-conversion (VTC) and time-digital-conversion (TDC). A Shared-MSB scheme is proposed and propagation delay of delay cells no longer depends on input voltages. Together with the fine-coarse conversion method, die area, matching difficulty and power consumption are reduced. The proposed ADC, containing 6 sub-ADCs with window from 1.0V to 1.4V, consumes die area of 0.065mm2 and power of 100µA implemented in 0.18µm process. And the conversion time is within 32ns. A SIMO DC-DC adopting the proposed ADC regulates the output voltage to 1.8V, 2.5V, 3.3V and 5.0V.

In this work, we report on the design of a wide-band digital lock-in amplifier (DLIA) of up to 65 MHz and its application for electrical impedance measurements in microfluidic devices. The DLIA is comprised of several dedicated technologies. First, it features a fully differential analog circuit, which includes a preamplifier with a low input noise of 4.4 nV/&radic, Hz, a programmable-gain amplifier with a gain of 52 dB, and an anti-aliasing, fully differential low-pass filter with &minus, 76 dB stop-band attenuation. Second, the DLIA has an all-digital phase lock loop, which features a phase deviation of less than 0.02&deg, throughout the frequency range. The phase lock loop utilizes an equally accurate period-frequency measurement, with a sub-ppm precision of frequency detection. Third, a modified clock link is implemented in the DLIA to improve the signal-to-noise ratio of the analog-to-digital converter affected by clock jitter of up to 20 dBc. A series of measurements were performed to characterize the DLIA, and the results showed an accurate performance. Additionally, impedance measurements of standard-size microparticles were performed by frequency sweep from 300 kHz to 30 MHz, using the DLIA in a microfluidic device. Different diameters of microparticle could be accurately distinguished according to the relative impedance at 2.5 MHz. The results confirm the promising applications of the DLIA in microfluidic electrical impedance measurements.

Effective coordination can dramatically reduce radio interference and avoid packet collisions for multistation wireless local area networks (WLANs). Coordination itself needs consume communication resource and thus competes with data transmission for the limited wireless radio resources. In traditional approaches, control frames and data packets are transmitted in an alternate manner, which brings a great deal of coordination overhead. In this paper, we propose a new communication model where the control frames can be "attacheda to the data transmission. Thus, control messages and data traffic can be transmitted simultaneously and consequently the channel utilization can be improved significantly. We implement the idea in OFDM-based WLANs called hJam, which fully explores the physical layer features of the OFDM modulation method and allows one data packet and a number of control messages to be transmitted together. hJam is implemented on the GNU Radio testbed consisting of eight USRP2 nodes. We also conduct comprehensive simulations and the experimental results show that hJam can improve the WLANs efficiency by up to 200 percent compared with the existing 802.11 family protocols.

MgO films were prepared by using pulsed cathodic vacuum arc deposition technique. The substrate bias voltage was in the range of −150 to −750 V. Film structure was investigated by X-ray diffraction (XRD). The annealing effect of thermal spike produced by the impacting of energetic ions was analyzed. The calculated results showed that the lifetime of a thermal spike generated by an energetic ion with the energy of 150 eV was less than one picosecond and it was sufficient to allow Mg2+ or O2- to move one bond length to satisfy the intrinsic stress relief in the affected volume. The MgO(200) lattice spacings of the films deposited at different bias voltages were all larger than the ideal value of 2.1056 A. As the bias amplitude increased the lattice spacing decreased, which indicated that the compressive stress in the film was partially relieved with increasing impacting ion energy. The stress relief also could be reflected from the film orientation with bias voltage. The biaxial elastic modulus for MgO(100), MgO(110) and MgO(111) planes were calculated and they were M(100) = 199 GPa, M(110) = 335 GPa and M(111) = 340 GPa, respectively. The M values indicated that the preferred orientation will be MgO(200) due to the minimum energy configuration when the lattice strain was large. It was confirmed by the XRD results in our experiments.

A carbon/TiO2 nanocomposite, which consists of carbon film with various sp3C content and TiO2 nanowire arrays, has been synthesized, in which the top surface of TiO2 nanowire arrays prepared using hydrothermal method on fluorine-doped tin oxide glass were coated with carbon thin films. The carbon thin films with a higher, medium and lower sp3C content were deposited by pulsed magnetic filtered cathodic vacuum arc deposition, plasma-enhanced chemical vapor deposition and magnetron sputtering deposition, respectively. The surface morphology and structure of TiO2 nanowire arrays were investigated by scanning electron microscopy, transmission electron microscope and X-ray diffraction. The sp3C content in carbon films was characterized using Raman spectroscopy. The blood compatibility of the samples including the TiO2 nanowire arrays, carbon films and carbon/TiO2 nanocomposite was assessed by tests of platelet adhesion in vitro. Results showed that the carbon/TiO2 composite can effectively improve the anticoagulant function compared to the single materials. It is believed that the excellent blood compatibility of the carbon/TiO2 nanocomposite is attributed to a joint function of surface properties adjusted by nanowire arrays and electronic structure of carbon thin films.

Indoor positioning systems have received increasing attention for supporting location-based services in indoor environments. WiFi-based indoor localization has been attractive due to its open access and low cost properties. However, the distance estimation based on received signal strength indicator (RSSI) is easily affected by the temporal and spatial variance due to the multipath effect, which contributes to most of the estimation errors in current systems. In this work, we analyze this effect across the physical layer and account for the undesirable RSSI readings being reported. We explore the frequency diversity of the subcarriers in orthogonal frequency division multiplexing systems and propose a novel approach called FILA, which leverages the channel state information (CSI) to build a propagation model and a fingerprinting system at the receiver. We implement the FILA system on commercial 802.11 NICs, and then evaluate its performance in different typical indoor scenarios. The experimental results show that the accuracy and latency of distance calculation can be significantly enhanced by using CSI. Moreover, FILA can significantly improve the localization accuracy compared with the corresponding RSSI approach.

A novel scaling algorithm is proposed which consists of a bicubic interpolation and an adaptive sharpening filter. The proposed sharpening filter is added to mitigate the blurring effects existing in bicubic interpolation methods. We also verify the scaling quality by taking into account the adaptive technique. Furthermore, we present both the procedures of filtering before and after interpolation in order to reduce the overall computing time. Compared with the previous reported techniques, our method performs better in terms of both quantitative evaluation and visual quality. To achieve the goal of real time and low cost, we describe a pipelined very large scale integration (VLSI) architecture for the implementation of the algorithm. The VLSI architecture of our image scaling processor contains 695 LEs and yields a processing rate of about 165 MHz by using field-programmable gate array (FPGA) technology. Our proposed architecture reduces the amount of gates by 36.8% while achieves an average PSNR increase of 1.5 dB in image quality.

Zinc Oxide (ZnO) thin films were prepared by cathodic vacuum arc deposition (CVAD) and filtered cathodic vacuum arc deposition (FCVAD) technology with a mixture of O2, Ar and N2. XRD patterns indicated that ZnO thin films prepared by CVAD had a combined orientation of ZnO (002) and ZnO (101). The preferential orientation ZnO (002) could be obtained at an optimum deposition pressure. On the other hand, a perfectly oriented ZnO (002) thin film prepared by FCVAD was obtained in lower pressure, which was beneficial to enhance the crystallization. The wetting behavior showed that all the ZnO thin films prepared by FCVAD were hydrophobic with low surface energy, but the reference samples of the polyurethane (PU) and glass are hydrophilic. Platelet adhesion test indicated that fewer platelets adhered and aggregated on the ZnO thin films prepared by FCVAD. The mechanism of hemocompatibility of ZnO thin films has also been investigated. It is suggested that hydrophobic surface with lower polar component and adhesive work are the two factors responsible for the excellent hemocompatibility.

Carbon plasma nanocoatings with controlled fraction of sp(3)-C bonding were deposited on TiO2 nanorod arrays (TNAs) by DC magnetic-filtered cathodic vacuum arc deposition (FCVAD). The cytocompatibility of TNA/carbon nanocomposites was systematically investigated. Human umbilical vein endothelial cells (HUVECs) were cultured on the nanocomposites for 4, 24, and 72 h in vitro. It was found that plasma-treated TNAs exhibited excellent cell viability as compared to the untreated. Importantly, our results show that cellular responses positively correlate with the sp(3)-C content. The cells cultured on high sp(3)-C-contented substrates exhibit better attachment, shape configuration, and proliferation. These findings indicate that the nanocomposites with high sp(3)-C content possessed superior cytocompatibility. Notably, the nanocomposites drastically reduced platelet adhesion and activation in our previous studies. Taken together, these findings suggest the TNA/carbon scaffold may serve as a guide for the design of multi-functionality devices that promotes endothelialization and improves hemocompatibility.

Modification of hydrogen-free diamond-like carbon (DLC) is presented, with acrylic acid (AA) vapor carried into a vacuum chamber by argon and with the in situ assistance of low-power radio frequency (RF) plasma at a temperature below 100°C. Measured by atomic force microscopy (AFM) technique, the roughness (Ra) of the DLC was 1.063±0.040 nm. XPS and FT-IR spectra analysis showed that carboxyl groups were immobilized on the surface of the DLC films, with about 40% of carboxyl group area coverage. It was found that the RF plasma and reaction time are important in enhancing the modification rate and efficiency.

Voltage drop introduced by long cable cannot be neglected any more in high-power remote-loading applications, e.g., power adaptor for the charger of modern smart phones or tablets. In this paper, self-adaptive wire drop compensation (WDC) schemes for DC-DC regulator have been proposed and discussed. A 3.5-A buck DC-DC regulator with the proposed WDC circuit has been implemented in 0.6μm CMOS technology. Simulation results show that the load regulation (0.004 V/A) is typically improved by 51 times than the circuit without WDC when load current changes from 0.5 A to 3 A.

MgO thin films with high optical transmittances (more than 90%) were prepared by cathodic vacuum arc deposition technique. With the increase of arc current from 40 to 80 A, the deposition pressure decreases and the film thickness increases; the atomic ratio of Mg/O in MgO thin films (obtained by RBS) increases from 0.97 to 1.17, giving that deposited at 50 A most close to the stoichiometric composition of the bulk MgO; the grains of MgO thin films grow gradually as shown in SEM images. XRD patterns show that MgO (1 1 0) orientation is predominant for films prepared at the arc currents ranged from 50 to 70 A. The MgO (1 0 0) orientation is much enhanced and comparable to that of MgO (1 1 0) for films prepared at the arc current of 80 A. The secondary electron emission coefficient of MgO thin film increases with arc current ranged from 50 to 70 A.

Europium-doped gadolinium oxide (Gd2O3:Eu3+) nanoparticles (NPs) with favorable properties for use in fluorescence imaging (FI) and magnetic resonance imaging (MRI) dual-modal contrast agent has attracted intense attention in biomedical applications. However, limited information is available on balancing FI and MRI by adjusting doping concentrations. In this study, Gd2O3:Eu3+ NPs with various Eu3+ doping concentrations were prepared by the facile and general technique of laser ablation in liquid (LAL). The influence of Eu3+-doping concentration on fluorescence properties and longitudinal relaxivity were investigated. The optimum Eu3+-doping concentration with both high fluorescence properties and longitudinal relaxivity was determined to be 5%. The characterization of the structure, morphology, and composition shows that these NPs possess good crystallinity and excellent dispersibility. These results show that Gd2O3:Eu3+ NPs prepared by LAL are promising candidates for highly efficient FI and MRI dual-modal contrast agents.

Total optical phase logic gates are reported in this paper. They are constructed by coupled-defect photonic crystal after two problems are overcome by a heterostructure or an asymmetric structure. Both half and all-phase logic gates are discussed. The sensitivity of these total optical phase logic gates not only are two orders sensitive than those using amplitude-signal, but also have many other advantages: such as very low energy cost. By using such phase logic gates, only a continued wave laser with one frequency is sufficient to operate the phase logic gate or the whole optical integrated circuit.

La(2)O(3) doped titanium oxide (TiO(2)) films with different concentration were deposited by means of the Radio-Frequency magnetron sputtering technique. The microstructure and surface properties of TiO(2) films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and contact angle test. The blood compatibility of the specimens was evaluated by tests of platelet adhesion. Results show that pure rutile phase is formed in doped samples and La(2)O(3) incorporation significantly improves the wettability and hemocompatibility of TiO(2) films. Our studies demonstrate that La(2)O(3) doped TiO(2) films are potentially useful biomaterials with good blood compatibility.

A general acid vapor oxidation (AVO) strategy has been developed to grow highly oriented hierarchically structured rutile TiO(2) nanoarrays with tunable morphologies from titanium thin films. This is a simple one-pot synthesis approach involving the reaction of a titanium surface with the vapor generated from a hydrochloric acid solution in a Teflon lined autoclave. To the best of our knowledge, this is the first successful attempt to grow ordered tree-like titania nanoarrays. A possible formation mechanism for the interesting architectures has been proposed based on series of time-dependent experiments. By adjusting the initial HCl concentration, films of different rutile structures including nanotrees, dendritic nanobundles, and nanorods can be selectively obtained. Subsequently, the surface morphologies and wettability can be readily tuned.

La 2 O 3 doped diamond-like carbon films (DLC) with different concentration were deposited by using Radio-Frequency magnetron sputtering. The microstructure and surface properties of DLC films were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and contact angle test. The blood compatibility of the samples was evaluated by tests of platelet adhesion. Results show the sp 2 -bonded C content increases with increasing of La 2 O 3 concentration doped. A remarkable decrease of platelet adhered on the surface of the La 2 O 3 doped DLC films was observed comparing to the Chrono flex used in clinical application, suggesting that La 2 O 3 doped DLC is able to enhance its blood compatibility. The mechanism of hemocompatibility of doped films was discussed. Our results demonstrate that La 2 O 3 doped DLC films are potentially useful biomaterials with good blood compatibility.

We use Monte Carlo simulations to study the influence of dipolar interaction on the equilibrium magnetic properties of monodisperse single-domain ferromagnetic nanoparticles. Low field magnetizations simulated in zero field cooling (ZFC)/field cooling (FC) procedures and field-dependent magnetization curves above the blocking temperatures show strong dependence on the concentration and the spatial arrangement (cubic or random) of the magnetic particles. The field-dependent magnetizations can not be simply described by the T* model at relative low temperatures due to the interplay between anisotropy and dipolar interactions, as well as the spatial arrangement effect.

Tetrahedral amorphous hydrogenated carbon (ta–C:H) films with higher sp 3 C fraction were prepared using a magnetic-field-filter plasma stream deposition system. The influences of annealing on the microstructure, optical properties and blood compatibility of ta–C:H films were investigated by using Raman spectra, UV–visible optical absorption spectroscopy and tests of platelet adhesion, respectively. Results show that the graphitization of ta–C:H films is significantly promoted when annealing temperature over 400 °C, resulting in a decrease of optical band gap from 2.3 to 0.2 eV in a annealing temperature range of 200 °C–600 °C. The quantity and morphology of the adherent platelets on the surface of samples indicated that the blood compatibility of ta–C:H films significantly depend on annealing temperature, and retrogression origin of the blood-compatibility of ta–C:H films were analyzed and discussed.

A phenomenological model is employed to explain the departure of H/T scaling of tunneling magnetoresistance (TMR) in Co 0.43 (ZrO 2 ) 0.57 granular films (see [B.J. Hattink, M. Garcia del Muro, Z. Konstantinovic, X. Batlle, A. Labarta, Phys. Rev. B 73 (2006) 045418]). The model bases on the modification of Langevin function by taking into account the field-dependent correlation length, in the framework of Inoue–Maekawa model. Both TMR –H and TMR –H/T curves can be reproduced very well by this model, indicating that the interparticle coupling plays an important role on TMR in the interacting superparamagnetic systems. The influence of anisotropy and spin polarization of the magnetic particles on TMR –H/T curves is also discussed.

In this paper, we present a method using video codec technology to compress ECG signals. This method exploits both intra-beat and inter-beat correlations of the ECG signals to achieve high compression ratios (CR) and a low percent root mean square difference (PRD). Since ECG signals have both intra-beat and inter-beat redundancies like video signals, which have both intra-frame and inter-frame correlation, video codec technology can be used for ECG compression. In order to do this, some pre-process will be needed. The ECG signals should firstly be segmented and normalized to a sequence of beat cycles with the same length, and then these beat cycles can be treated as picture frames and compressed with video codec technology. We have used records from MIT-BIH arrhythmia database to evaluate our algorithm. Results show that, besides compression efficiently, this algorithm has the advantages of resolution adjustable, random access and flexibility for irregular period and QRS false detection.

Single crystals of MgO with (100), (110) and (111) orientations were implanted with 64 keV Fe ions at a dose of 1.9×1017 ions/cm2 by using metal-vapor vacuum arc ion source (MEVVA). The magnetic properties were investigated by a superconducting quantum interference device magnetometer and Rutherford backscattering spectrometry (RBS) was used to analyze the Fe concentration and distribution. The presence of Fe nanoparticles in MgO matrix was verified by magnetization measurements. Results show that all the samples behave with ferromagnetism at 5 K and 300 K, and the coercive field, H C , follow well the relation: H C ( 110 ) H C ( 100 ) H C ( 111 ) at measured temperatures. The orientation dependence of the coercive field may result from the different distribution of Fe nanoparticle size.

Tetrahedral amorphous hydrogenated carbon (ta-C:H) films with various substrate bias voltages were prepared using a magnetic-field-filter plasma stream deposition system. The microstructural and optical properties were studied using ellipsometric spectra. The refractive index n of each sample was obtained by simulating their ellipsometric spectral using Tauc–Lorentz oscillator model, and then the relative sp3 C ratio of each sample was calculated using Bruggeman effective medium approximation. The sp3 C fraction of each sample was quantified by using electron energy-loss spectroscopy (EELS). The blood compatibility of the samples was evaluated by tests of platelet adhesion, kinetic clotting time and thrombin time. The quantity and morphology of the adherent platelets on the surface of these samples were investigated using scanning electron microscopy. Results show that the spectroscopic ellipsometry is a helpful method to evaluate the sp3 carbon fraction of the carbon films. The substrate bias voltage has an obvious effect on sp3 content and blood compatibility of ta-C:H films. The sample prepared with substrate bias voltage of − 20 V showed the best blood compatibility. A simple bio-physical hypothetical model was proposed to explain the experiment results.

This study established a fully automated computer-aided diagnosis (CAD) system for the classification of malignant and benign masses via breast magnetic resonance imaging (BMRI). A breast segmentation method consisting of a preprocessing step to identify the air-breast interfacing boundary and curve fitting for chest wall line (CWL) segmentation was included in the proposed CAD system. The Chan-Vese (CV) model level set (LS) segmentation method was adopted to segment breast mass and demonstrated sufficiently good segmentation performance. The support vector machine (SVM) classifier with ReliefF feature selection was used to merge the extracted morphological and texture features into a classification score. The accuracy, sensitivity, and specificity measurements for the leave-half-case-out resampling method were 92.3%, 98.2%, and 76.2%, respectively. For the leave-one-case-out resampling method, the measurements were 90.0%, 98.7%, and 73.8%, respectively.