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This paper presents an analog baseband (ABB) circuit in a 0.13 μm SiGe technology for transmitter leakage cancellation and close-in blocker suppressions in fully duplex (FD) frequency-modulated continuous-wave (FMCW) radar. This ABB comprises a programmable gain amplifier (PGA) and a cascaded LPF/Notch hybrid, which incorporates a closed-loop (CL) reconfigurable low-pass filter (LPF) and an open-loop (OL) tunable notch filter. The adopted key topologies include active-RC bi-quads and Gm-C ones. In an FD FMCW transceiver, Tx leakage and close-in blockers are difficult to be eliminated in the RF domain, especially when leakage/blockers are very close to desired signals or even in-band in the frequency domain. This LPF/notch hybrid is proposed to solve this issue. The LPF and PGA provide bandwidth (BW)/gain programmability, while the Gm-C bi-quad provides adaptable center frequency for a notch filter. With this adaption, the notch filter could be adjusted to match the leakage/blocker offset frequency. Thus, digitally discrete programmability and analog continuous tuning capability are combined in this solution for improving the overall front-end interference robustness without de-sensitizing the Rx. Furthermore, the order of LPF/notch hybrid is programmable from 2 to 10 with a step of 2 for different rejection levels of interferences. The measured chip achieves a -3dB bandwidth of 6 21 MHz with 4-bit digital control and 1 MHz/step programmability, and a voltage gain of 0 70 dB with 9-bit digital control (3-bit from pre-amplifier, and 6-bit from PGA with 1 dB/step). With the condition of 15 dB gain, output P-1dB is 11.8 dBm@3MHz, and the output IP3 is 20.8 dBm@3MHz.

This paper presents a novel co-optimization configuration to simultaneously improve phase noise and FoM in order to solve the long-existing issue of excellent phase noise and mediocre FoM in the light of GaAs technologies. Considering traditional GaAs based Colpitts/class-C VCOs, a first step is taken with the introduction of noise shifting structure while a second step is carried out with the presentation of Darlington pair. Afterwards, a detailed outline of pros and cons of five VCO topologies, including Colpitts/class-C/noise shifting (NS) Colpitts/noise shifting class-C/noise shifting Darlington-based (NSDB) class-C VCO, is given in theory and in practice while respective start-up conditions and capacitive feedback factors are derived mathematically. It can be found that iterative phase noise and FoM improvement is achieved in GaAs based VCOs above in a gradual manner. Furthermore, the output power is stabilized with a simple trick of two-stage Darlington-based topology and thus, the power-hungry buffer is avoided. Ultimately, three VCOs out of the five are fabricated in GaAs technologies while their specifications are thoroughly compared with previous research. The fabricated Colpitts VCO demonstrates a frequency tuning range of 3.59–3.69 GHz with a current consumption of 11.2 mA@5 V supply, a phase noise of − 130.1 to − 129.1 dBc/Hz at 1 MHz offset from the carrier and the output power is around − 5 to − 5.1 dBm. The fabricated noise shifting Colpitts VCO demonstrates a frequency tuning range of 3.58–3.67 GHz with a current consumption of 10.8 mA@5 V supply, a phase noise of − 132.4 to − 130.2 dBc/Hz at 1 MHz offset from the carrier and the output power is around − 2.5 to − 3.5 dBm. The fabricated Darlington-based class-C VCO demonstrates a frequency tuning range of 2.76–2.91 GHz with a current consumption of 9.5 mA@5 V supply, a phase noise of − 138.6 to − 135.9 dBc/Hz at 1 MHz offset from the carrier and the output power is around − 3.06 to − 4.18 dBm. To the best of the authors’ expertise, the proposed Darlington-based class-C VCO achieves both exceptional phase noise and FoM, which far outweigh that of existing GaAs ones.

Micro sliding phenomenon widely exists in the operation process of mechanical systems, and the micro sliding friction mechanism is always a research hotspot. In this work, based on the total reflection method, a measuring device for interface contact behavior under two-dimensional (2D) vibration is built. The stress distribution is characterized by the light intensity distribution of the contact image, and the interface contact behavior in the 2D vibration process is studied. It is found that the vibration angle of the normal direction of the contact surface and its fluctuation affect the interface friction coefficient, the tangential stiffness, and the fluctuation amplitude of the stress distribution. Then they will affect the change of friction state and energy dissipation in the process of micro sliding. Further, an improved micro sliding friction model is proposed based on the experimental analysis, with the nonlinear change of contact parameters caused by the normal contact stress distribution fluctuation taken into account. This model considers the interface tangential stiffness fluctuation, friction coefficient hysteresis, and stress distribution fluctuation, whose simulation results are consistent well with the experimental results. It is found that considering the nonlinear effect of a certain contact parameter alone may bring a greater error to the prediction of friction behavior. Only by integrating multiple contact parameters can the accuracy of friction prediction is improved.

Highly spatial and angular precision in epitaxial-growth process is crucial for constructing organic low-dimensional heterostructures (OLDHs) with the desired substructures, which remains significant challenge owing to the unpredicted location of complex heterogeneous nucleation. Herein, a dynamic epitaxial-growth approach is developed along the tailored longitudinal/horizontal directions to create diverse OLDHs with hierarchical architectures. The controlled morphology evolution of seed crystals from kinetic to thermodynamic species is achieved via incrementally increasing the crystallization time from 0 to 600 s. Accordingly, the kinetic and thermodynamic seed crystals respectively present the specific lattice-matching crystal-planes of (100) and (011), which facilitates the longitudinal epitaxial-growth (LG) process for triblock heterostructures, and the horizontal epitaxial-growth (HG) process for axial-branch heterostructures. The dominant core/shell heterostructures are prepared via both LG and HG processes with a crystallization time of ≈30 s. Significantly, these prepared OLDHs realize the rationally polarized exciton conversion for optical logic gate application through the exciton conversion and photon propagation at the heterojunction. This strategy provides an avenue for the precise synthesis of OLDHs with anisotropy optical characters for integrated optoelectronics.

Nanoparticles (NPs) will inevitably interact with proteins and form protein coronas once they are exposed to biological fluids. This conventional model for nano-bio interactions has been used for over twenty years. Growing numbers of new nanomaterials are emerging every year. Among them, noble metal nanoclusters (NMNCs) are new types of fluorescent nanomaterials with considerable advantages in biomedical applications. Compared with NPs (typically >10 nm) like Au NPs, carbon nanotubes, etc., NMNCs have ultrasmall sizes (∼2 nm), so when NMNCs are exposed to biological milieu, will they form protein coronas like NPs? Due to a lack of characterization techniques for ultrasmall nanoparticles (USNPs), to date, studies on the binding stoichiometries of USNPs to proteins have been heavily hampered. To address this challenge, we combined the characteristics of various methods and selected human serum albumin (HSA) and transferrin (Trf) as model proteins to study their interactions with dihydrolipoic acid (DHLA) protected gold nanoclusters (DHLA-AuNCs). Steady-state fluorescence, transient fluorescence spectroscopy and isothermal titration calorimetry (ITC) were used to study the thermodynamic parameters (K, ΔH, ΔS, ΔG) and interaction mechanisms. The results showed that the intrinsic fluorescence of both proteins was quenched by DHLA-AuNCs, and the quenching process of HSA was an endothermic dynamic process. In contrast, the quenching process of Trf was an exothermic static process. The combination of ITC, agarose gel electrophoresis (AGE) and zeta potential showed that one HSA could bind 8 ± 1 DHLA-AuNCs and one Trf could bind 7 ± 2 DHLA-AuNCs, which was quite different from the conventional model of protein coronas. Based on these findings, the "protein complex" was termed for proteins upon binding with USNPs. Dynamic light scattering (DLS), transmission electron microscopy (TEM), and atomic force microscopy (AFM) showed that DHLA-AuNCs could induce the agglomeration of proteins. Circular dichroism (CD) and synchronous fluorescence spectroscopy showed that DHLA-AuNCs had a very minor effect on the secondary structures of HSA and Trf, which demonstrated the good biocompatibility of DHLA-AuNCs at the molecular scale. This work has shed light on a new interaction model beyond the protein corona, indicating a possible biological identity of USNPs.

A highly reconfigurable open-loop analog baseband circuitry with programmable gain, bandwidth and filter order are proposed for integrated linear frequency modulated continuous wave (LFMCW) radar receivers in this paper. This analog baseband chain allocates noise, gain and channel selection specifications to different stages, for the sake of noise and linearity tradeoffs, by introducing a multi-stage open-loop cascaded amplifier/filter topology. The topology includes a course gain tuning pre-amplifier, a folded Gilbert variable gain amplifier (VGA) with a symmetrical dB-linear voltage generator and a 10-bit R-2R DAC for fine gain tuning, a level shifter, a programmable Gm-C low pass filter, a DC offset cancellation circuit, two fixed gain amplifiers with bandwidth extension and a novel buffer amplifier with active peaking for testing purposes. The noise figure is reduced with the help of a low noise pre-amplifier stage, while the linearity is enhanced with a power-efficient buffer and a novel high linearity Gm-C filter. Specifically, the Gm-C filter improves its linearity specification with no increase in power consumption, thanks to an alteration of the trans-conductor/capacitor connection style, instead of pursuing high linearity but power-hungry class-AB trans-conductors. In addition, the logarithmic bandwidth tuning technique is adopted for capacitor array size minimization. The linear-in-dB and DAC gain control topology facilitates the analog baseband gain tuning accuracy and stability, which also provides an efficient access to digital baseband automatic gain control. The analog baseband chip is fabricated using 130-nm SiGe BiCMOS technology. With a power consumption of 5.9~8.8 mW, the implemented circuit achieves a tunable gain range of &minus, 30~27 dB (DAC linear gain step guaranteed), a programmable &minus, 3 dB bandwidth of 18/19/20/21/22/23/24/25 MHz, a filter order of 3/6 and a gain resolution of better than 0.07 dB.

Hierarchical self-assembly nanomaterials with high spatial/angular precision have attracted intensive attention in the urgent research focus in industrial and environmental fields, such as the efficient removal of heavy metal ions from aqueous solution. Herein, we developed an facile microwave-induced ultrasonic hydrolysis approach for the fine synthesis of the hierarchical CuO/Cu(OH)2 urchin-like nanoparticles, which is comprised by Cu-based substructure nanowires with an average diameter of ~5 nm. Benefiting from the high specific surface area of 230.67 m2/g, the urchin-like CuO/Cu(OH)2 hierarchical nanoparticles demonstrated a high maximum adsorption capacity of 357.25 mg/g at pH = 6.0 and T = 298 K for Cr(VI). Furthermore, the corresponding removed approximately 95% can be achieved after the adsorption process for 30 min, suggesting the fast adsorption for Cr(VI). Thermodynamic and kinetic investigations revealed that the Cr(VI) adsorption on the urchin-like CuO/Cu(OH)2 hierarchical nanoparticles was an endothermic and spontaneous process, which could be well fitted by the pseudo-second-order kinetic model. This approach provides new prospects for curbing heavy metal pollution in the environment based on the hierarchical self-assembly nanomaterials.

As-cast AlCrFeNi2Ti0.5 high entropy alloy was annealed at 600 °C and 800 °C for 6 h, 12 h and 24 h, respectively. The effect of annealing time on the microstructure and mechanical properties were investigated intensively. The as-cast sample showed a fine and homogeneous microstructure, and owned an excellent ductility of 16.3%. While the 600 °C, 12 h annealed sample showed the highest compressive strength of 2658 MPa and yield strength of 2046 MPa. The mechanical properties of the samples after 800 °C annealed for 12 h and 24 h deteriorated obviously. High annealing temperature promotes the growth of the crystal grains, and the new generated FeCr-type intermetallic phase leads to the embrittlement of the alloy.

In recent years, with the rapid development of data intensive applications, data replication has become an enabling technology for the data grid to improve data availability, and reduce file transfer time and bandwidth consumption. The placement of replicas has been proven to be the most difficult problem that must be solved to realize the process of data replication. This paper addresses the quality of service (QoS) aware replica placement problem in data grid, and proposes a dynamic programming based replica placement algorithm that not only has a QoS requirement guarantee, but also can minimize the overall replication cost, including storage cost and communication cost. By simulation, experiments show that the replica placement algorithm outperforms an existing popular replica placement technique in data grid.

In this paper, we address the issue of soil roughness characterisation in the case of agricultural fields having different tillage (roughness) states, that is ploughed, harrowed and rolled surface. By using a laser profiler, the surface height variation trace of three types of tillage soil profiles are obtained. Using this dataset the range of RMS height, autocorrelation length and the fractal characteristic values associated with each agricultural roughness state is estimated, The result show that fractal dimension turned out to be a suitable index for distinguish the different tillage states. But there is no one-to-one correspondence relationship. A soil roughness index was found to be appropriate for the quantification of soil surface roughness.

In this paper, a new genetic algorithm method to optimize the frequency selective surface(FSS) is presented. The optimization speed and definition are promoted by limiting the parameter range and changing the genetic basis. A new cost function is introduced to optimize the multi-frequency of FSS by multi-object optimization (MO). The cirque element was optimized by the optimization method, fabricated by the selective electroless plating on fabric and measured by the arch test system. Test result proves the simulated result coincide with measured result. Result shows that it’s possible to realize different optimizations based on the various applying by this method.

Tetranychus cinnabarinus(Acari: Tetranychidae) is a worldwide polyphagous agricultural pest that has the title of resistance champion among arthropods. We reported previously the identification of the acaricidal compoundβ-sitosterol fromMentha piperitaandInula japonica. However, the acaricidal mechanism ofβ-sitosterol is unclear. Due to the limited genetic research carried out, wede novoassembled the transcriptome ofT. cinnabarinususing Illumina sequencing and conducted a differential expression analysis of control andβ-sitosterol-treated mites. In total, we obtained >5.4 G high-quality bases for each sample with unprecedented sequencing depth and assembled them into 22,941 unigenes. We identified 617 xenobiotic metabolism-related genes involved in detoxification, binding, and transporting of xenobiotics. A highly expanded xenobiotic metabolic system was found in mites.T. cinnabarinusdetoxification genes—including carboxyl/cholinesterase and ABC transporter class C—were upregulated afterβ-sitosterol treatment. Defense-related proteins, such as Toll-like receptor, legumain, and serine proteases, were also activated. Furthermore, other important genes—such as the chloride channel protein, cytochromeb, carboxypeptidase, peritrophic membrane chitin binding protein, and calphostin—may also play important roles in mites’ response toβ-sitosterol. Our results demonstrate that high-throughput-omics tool facilitates identification of xenobiotic metabolism-related genes and illustration of the acaricidal mechanisms ofβ-sitosterol.

The carmine spider mite, Tetranychus cinnabarinus (Boisduval), is a major agriculture pest. It can be found worldwide, has an extensive host plant range, and has shown resistance to pesticides. Organophosphate and carbamate insecticides account for more than one-third of all insecticide sales. Insecticide resistance and the toxicity of organophosphate and carbamate insecticides to mammals have become a growing concern. Acetylcholinesterase (AChE) is the major targeted enzyme of organophosphate and carbamate insecticides. In this study, we fully cloned, sequenced and characterized the ace1 gene of T. cinnabarinus, and identified the differences between T. cinnabarinus AChE1, Tetranychus urticae Koch AChE1, and human AChE1. Resistance-associated target-site mutations were displayed by comparing the AChE amino acid sequences and their AChE three-dimensional (3D) structures of the insecticide-susceptible strains of T. cinnabarinus and T. urticae to that of a T. urticae-resistant strain. We identified variation in the active-site gorge and the sites interacting with gorge residues by comparing AChE1 3D structures of T. cinnabarinus, T. urticae, and humans, though their 3D structures were similar. Furthermore, the expression profile of T. cinnabarinus AChE, at the different developmental stages, was determined by quantitative real-time polymerase chain reaction; the transcript levels of AChE were higher in the larvae stage than in other stages. The changes in AChE expression between different developmental stages may be related to their growth habits and metabolism characteristics. This study may offer new insights into the problems of insecticide resistance and insecticide toxicity of nontarget species.