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A new compact wideband filtering balun based on substrate-integrated suspended line technology is presented in this brief. The proposed device is composed of a λg/4 suspended stripline open-circuited stub, a λg/2 suspended stripline resonator, and a λg/2 suspended slotline resonator. These striplines and slotline are encapsulated in an electromagnetic (EM) shielding box consisting of air cavity, surrounding substrate layers, and metal layers to achieve EM shielding performance. By properly exciting the suspended stripline and slotline resonators, three transmission poles are generated to achieve high frequency selectively. The intrinsic 180∘ phase difference between the two output ports can be obtained by using the electric field distribution caused by the perpendicular coupling between the suspension stripline and the slotline resonator. The wideband passband is achieved with magnitude balance and out-of-phase properties. To validate our proposal, a wideband filtering balun operating at 2.56 GHz with fractional bandwidth of 65.6% is designed and fabricated.
Early maturity allows weedy rice (Oryza sativa L. f. spontanea) to persist by escaping harvest in paddy fields. A shorter grain-filling period contributes to the early maturity of weedy rice. However, the differences in morphology and endosperm development in the caryopsis between weedy and cultivated rice are largely unexplored. Here, we selected four biotypes of weedy rice and associated cultivated rice (ACR; Oryza sativa) from different latitudes to conduct a common garden experiment. The endosperm development process of the caryopsis was observed by optical microscopy and electron microscopy. Endosperm cell division and starch accumulation rate during grain filling were also measured. The grain development progress in weedy rice was more rapid and earlier than that in ACR. The endosperm development progress of weedy rice was 6 to 8 d earlier than that of ACR. The endosperm cells of weedy rice cellularized earlier and more rapidly than those of ACR, and the starch grains of weedy rice were more sharply polygonal and compactly arranged than those of ACR. The active endosperm cell division period in weedy rice was 4 to 7 d shorter than that in ACR, while the active starch accumulation period of weedy rice was 2 to 8 d shorter than that of ACR. The rapid development of endosperm cells and starch grains leads to the shorter grain-filling period of weedy rice. weedy rice.
TRIM28/KAP1/TIF1β was identified as a universal transcriptional co-repressor and is critical for regulating post-fertilization methylation reprogramming in preimplantation embryos. In this study, three siRNAs (si647, si742, and si1153) were designed to target the TRIM28 mRNA sequence. After transfection of the mixture of the three siRNA (siMix) into bovine fibroblast cells, the most effective one for TRIM28 knockdown was selected. By injecting RNAi directed against TRIM28 mRNA, we found that TRIM28 knockdown in oocytes had the most effect on the H19 gene, in which differentially methylated region (DMR) methylation was almost completely absent at the 2-cell stage (1.4%), while control embryos showed 74% methylation. In addition, global H3K9me3 levels at the 2-cell stage were significantly higher in the in vitro fertilization (IVF) group than in the TRIM28 knockdown group (P<0.05). We further show that TRIM28 is highly expressed during oocyte maturation and reaches peak levels at the 2-cell stage. In contrast, at this stage, TRIM28 expression in somatic cell nuclear transfer (SCNT) embryos decreased significantly (P<0.05), suggesting that Trim28 transcripts are lost during SCNT. TRIM28 is required for the maintenance of methylation imprints in bovine preimplantation embryos, and the loss of TRIM28 during SCNT may contribute to the unfaithful maintenance of imprints in cloned embryos.
Path planning under 2D map is a key issue in robot applications. However, most related algorithms rely on point-by-point traversal. This causes them usually cannot find the strict shortest path, and their time cost increases dramatically as the map scale increases. So we proposed RimJump to solve the above problem, and it is a new path planning method that generates the strict shortest path for a 2D map. RimJump selects points on the edge of barriers to form the strict shortest path. Simulation and experimentation prove that RimJump meets the expected requirements.
A series of novel wideband filtering power dividers (WFPDs) with wide stopband rejection performances is proposed in this paper. The proposed WFPD structure consists of a parallel-coupled line, two transmission line (TL) sections, four loading terminations, and an isolation resistor. The coupled line is applied at the input port to provide wideband impedance transformation, while different types of loading terminations and TL sections are adopted to realize various out-of-band rejection performances. To verify the proposed concepts, three WFPDs operating at 3.0 GHz are designed and fabricated with 3 dB bandwidth of 79.7, 79.0, and 74.4%. In WFPD1, the measured out-of-band rejection of better than 13.4 dB extends to 2.57f0. Moreover, the measured out-of-band rejection of better than 17 dB extends to 2.47f0 (4.75f0) in WFPD2 (WFPD3), respectively. Good agreements between the simulated and measured results validate the presented ideas.
By solving the problems in the previous pragmatic method [Scr. Mater.90–91, 53–56 (2014)] and including the interdiffusion flux as the criteria, an augmented numerical inverse method was proposed and realized in a house-made code. The proposed augmented numerical inverse method was successfully applied to high-throughput determination of the composition-dependent interdiffusivities in different solid solution alloys ranging from binary, ternary to multicomponent systems by using a single diffusion couple. Moreover, the advance features of the augmented numerical inverse method were also demonstrated.
We investigate the influence of the initial size of the proton layer on proton acceleration in the interaction of high intensity laser pulses with double-layer targets by using two-dimensional particle-in-cell code. We discuss the influence of proton layer initial sizes on the cut-off energy, energy spread, and divergence angle of proton beam. It is found that Coulomb explosion plays an important role on the proton cut-off energy. This causes the cut-off energy to increase for increasing proton layer thickness, at the expense of energy spread. The proton divergence angle reaches a peak value and then falls again with increasing the width. Proton divergence angle grows with target thickness. It is found that there is an optimal thickness to obtain the narrowest energy spread, which may provide an effective method (change the size of proton layer) to obtain high quality proton beams. This work may serve to improve the understanding of sheath field proton acceleration.
In fast ignition of inertial confinement fusion, hot electron beam is considered to be an appropriate energy source for ignition. However, hot electrons are divergent as they are transporting in over-dense plasma. So collimating the hot electrons becomes one of the most important issues in fast ignition. A method to collimate hot electron beam by external magnetic field is proposed in this paper. The external field can be generated by compressing a seed magnetic field at the stage of laser-driven implosion. This method is confirmed by particle-in-cell simulations. The results show that hot electrons are well collimated by external magnetic field from magnetic-flux compression.
The laser-driven acceleration of proton beams from a double-layer cone target, comprised of a cone shaped high-Z material target with a low density proton layer, is investigated via two-dimensional fully relativistic electro-magnetic particle-in-cell simulations. The dependence of the inside diameter (ID) of the tip size of a double-layer cone target on proton beam characteristics is demonstrated. Our results show that the peak energy of proton beams significantly increases and the divergence angle decreases with decreasing ID size. This can be explained by the combined effects of a stronger laser field that is focused inside the cone target and a larger laser interaction area by reducing the ID size.
Laser plasma experiments, which demonstrated the single order diffraction property of spectroscopic photon sieve (a novel single-order diffraction grating), were performed on the SILEX-I femto-second laser facility. High-intensity laser radiation was focused onto a Cu target to generate plasma. The spectra of soft X-ray from copper plasmas have been measured with spectroscopic photon sieve based spectrograph. The results show that the spectroscopic photon sieve is able to provide soft X-ray spectrum free from higher-order diffraction components. The measured spectra obtained with such a spectroscopic photon sieve need no unfolding process to extract higher-order diffraction interference.
A scheme capable of enhancing the energy of monoenergetic protons in high intensity laser-plasma interactions is proposed and demonstrated by two dimensional particle-in-cell simulations. The focusing of laser light pulse and the guiding of surface current via the high Z material cone-shaped substrate increase the temperature of hot electrons, which are responsible for the electrostatic field accelerating protons. Moreover, the sub-micron proton layer coated on the cone-shaped substrate makes the total proton beam experience the same accelerating field, thus the monochromaticity is maintained. Compared to the normal film double layer target, the energy of monoenergetic proton beams can be improved about three times.
This paper explores the design of humanoid complicated dynamic motion based on human motion capture. Captured human data must be adapted for the humanoid robot because its kinematics and dynamics mechanisms differ from those of the human actor. It is expected that humanoid movements are highly similar to those of the human actor. First, the kinematics constraints, including ground contact conditions, are formulated. Second, the similarity evaluation on the humanoid motion based on both the spatial and temporal factors compared with the human motion is proposed. Third, the method to obtain humanoid motion with high similarity is presented. Finally, the effectiveness of the proposed method is confirmed by simulations and experiments of our developed humanoid robot “sword” motion performance.
A single-chip IEEE 802.11g compliant wireless LAN system-on-a-chip (SoC) that implements all RF, analog, digital PHY and MAC functions has been integrated in a 0.18-µm CMOS technology. The IC transmits 0 dBm EVM-compliant output power for a 64 QAM OFDM signal. The overall receiver sensitivities are better than -92 dBm and - 73 dBm for data rates of 6 Mbps and 54 Mbps, respectively.
The IEEE 802.11g specification which was only ratified in June 2003, has become the most widely deployed wireless local area network (WLAN) standard today. Its popularity is due in large part to its support for higher data rates while maintaining backwards compatibility to legacy IEEE 802.11b WLANs. An IEEE 802.11g device achieves the higher data rate when communicating with other 802.11g devices by using orthogonal frequency division multiplexing (OFDM) modulation. When communicating with legacy 802.11b devices, it will revert back to either direct sequence spread spectrum (DSSS) or complementary code keying (CCK) modulation. The standard uses 83.5-MHz of available spectrum in the 2.4-GHz band and allows for three non-overlapping channels. The data rates range from 1-2 Mbps using DSSS modulation, 5.5-11 Mbps using CCK modulation, and 6-54 Mbps using OFDM modulation. As in the IEEE 802.11a specification the OFDM in 802.11g uses 52 sub-carriers, each of which can be modulated with BPSK, QPSK, 16-QAM or 64-QAM.
The rapid adoption of IEEE 802.11g WLANs and their growing popularity in portable applications such as PDAs and cellphones highlighted the need for a low-cost, small form factor solution.
A new 3-DOF translational parallel manipulator is presented in this paper. This manipulator has decoupled motion in for x, y, and z axes, and employs only revolute joints. The structure and kinematics of the manipulator are studied. The mechanism singularity is examined and the calibration methods are presented.
Motion coupling is one of the typical characters of parallel robots. This makes it complicated to control the parallel robots. Therefore, the design of parallel mechanisms with decoupled motions is an important and challenging issue in the parallel robotic field. However, research in this field, including the definition and type synthesis theory, is weak or lacking. In this paper, the reducible correlation between the input and the output of 3-DOF translational mechanisms with decoupled motions is investigated and the definition of this topic is presented. A new parameter named Gf coordinate is propsed for the synthesis of 3-DOF reducible translational mechanisms. The type synthesis theory for this kind of mechanisms is obtained and some reducible mechanisms are synthesized.
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