A 23 GHz Active Mixer with Integrated Diode Linearizer in SiGe BiCMOS Technology

Active mixers operating at 23 GHz are designed and fabricated in SiGe technology.An integrated diode linearizer is used to improve the linearity of the mixer.Measurement and simulation show excellent agreement.Typically,10 dB double-sideband noise figure, 10 dBm IIP3 and 2 dB conversion gain are measured, featuring low noise and high linearity in a same design

A Novel Tomato Volume Measurement Method based on Machine Vision

Density is one of the auxiliary indicators for judging the internal quality of tomatoes. However, in the density measurement process, it is often difficult to measure the volume of the tomatoes accurately. To solve this problem, first, this study proposed a novel tomato volume measurement method based on machine vision. The proposed method uses machine vision to measure the geometric feature parameters of tomatoes, and inputs them into the LabVIEW software to convert the calculation of irregular tomato volume into a BP neural network (BPNN) model that calculates the plane pixel area and pixel volume, thereby realizing the modeling, analysis, design and simulation of tomato volume; then, an experimental platform was constructed to compare the results of the proposed method with the results predicted by the 3D wireframe model. When the number of photos taken was n = 5, the average error of the tomato volume prediction results of the 3D wireframe model was 8.22%, and the highest accuracy was 92.93%; while the average error of the tomato volume prediction results of the BPNN was 4.60%, and the highest accuracy was 95.60%. Increasing the number of orthographic projections can improve the accuracy of the model, but when the number of photos was more than 7, the accuracy improvement was not significant. Also, increasing the number of nodes in the hidden layer can improve the accuracy of the model, however, considering that increasing the number of nodes will increase the host operating cost, it is suggested to choose a node number of 12 for the tomato volume measurement. In the end, the final experimental results showed that the proposed method achieved better measurement results. However, the volume measured by the two models is larger than the real volume of tomatoes. For this reason, we added a correction coefficient to the BPNN model, and its highest accuracy has increased by 1.3%

Simulation Design of a Tomato Picking Manipulator

Simulation is an important way to verify the feasibility of design parameters and schemes for robots. Through simulation, this paper analyzes the effectiveness of the design parameters selected for a tomato picking manipulator, and verifies the rationality of the manipulator in motion planning for tomato picking. Firstly, the basic parameters and workspace of the manipulator were determined based on the environment of a tomato greenhouse; the workspace of the lightweight manipulator was proved as suitable for the picking operation through MATLAB simulation. Next, the maximum theoretical torque of each joint of the manipulator was solved through analysis, the joint motors were selected reasonably, and SolidWorks simulation was performed to demonstrate the rationality of the material selected for the manipulator and the strength design of the joint connectors. After that, the trajectory control requirements of the manipulator in picking operation were determined in view of the operation environment, and the feasibility of trajectory planning was confirmed with MATLAB. Finally, a motion control system was designed for the manipulator, according to the end trajectory control requirements, followed by the manufacturing of a prototype. The prototype experiment shows that the proposed lightweight tomato picking manipulator boasts good kinematics performance, and basically meets the requirements of tomato picking operation: the manipulator takes an average of 21 s to pick a tomato, and achieves a success rate of 78.67%

Transition from one- to two-dimensional island growth on metal (110) surfaces induced by anisotropic corner rounding

We propose a kinetic model to describe the temperature dependence of the shape of islands formed during submonolayer epitaxy on anisotropic metal surfaces. Our model reveals that anisotropic corner rounding is the key atomic process responsible for a transition in island shape, from chain structures at lower temperatures, to compact islands at higher temperatures. Exploiting data for the temperature and flux scaling of the island density, we analyze such behavior observed experimentally in Cu/Pd(110) epitaxy, estimating activation barriers of 0.45 and 0.3 eV for anisotropic terrace diffusion, and 0.65 eV for the slow corner-rounding process

Effect of a 180 mg ticagrelor loading dose on myocardial necrosis in patients undergoing elective percutaneous coronary intervention: A preliminary study

Background: To examine whether a loading dose of ticagrelor on top of clopidogrel reduced postpercutaneous coronary intervention (PCI) myonecrosis. Methods: Seventy seven coronary artery disease patients received a loading dose of 300 mg clopidogrel pre-PCI and were divided into three groups: group TT (n = 36): a loading dose of 180 mg ticagrelor pre-PCI, followed by ticagrelor 90 mg twice daily commencing one day post-PCI; group CT (n = 26): a maintenance dose of ticagrelor 90 mg twice daily; group CC (n = 15): clopidogrel 75 mg daily post- PCI. High sensitivity cardiac troponin T (hs-cTnT) and creatine kinase-MB (CK-MB) were measured pre-PCI and 0 h, 2 h or 24 h post-PCI. Platelet aggregation was measured in a separate cohort of 54 coronary artery disease patients (35 diabetic and 19 non-diabetic patients). Results: There were no significant differences in hs-cTnT and CK-MB concentration among the three groups. In group TT, diabetic patients had significant higher Δhs-cTnT2h–0h than non-diabetic patients. In the second cohort, although baseline platelet aggregation was higher in diabetic than non-diabetic patients, platelet aggregation was comparable between diabetic and non-diabetic patients at 0 and 2 h post-PCI. Conclusions: This study indicates that a loading dose of ticagrelor does not significantly reduce post- PCI myonecrosis. Diabetes is associated with more post-PCI myonecrosis. A loading dose of ticagrelor effectively reduces platelet aggregation in diabetic patients.

Effect of the shelterbelt along the Tarim Desert Highway on air temperature and humidity

The temperature and humidity of the shelterbelt micro-climate on both horizontal and vertical scales in the extremely drought area were measured with multiple HOBO temperature and humidity automatic observation equipments in the hinterland of the Taklimakan Desert. The results show that the shelterbelt ecosystem of the desert highway plays typical micro-climate adjustment rolesin stabilizing surface air temperature and increasing air humidity, and so on. Solar radiation significantly affects both temperature and humidity of surface layers, and it has a positive correlation with the temperature but a negative correlation with the air humidity. When it is cloudy, the weather has a great impact on keeping temperature and humidity in the shelterbelt. The shelterbelt also significantly influences the environment, and the micro-climate in the belt has an obvious characteristic of cooling and humidification: compared with the original sand area, the temperature in the shelterbelt is always lower and the humidity is always higher. Moreover, the temperature range at the shelterbelt edge is greater than that in the sand area, but the humidity is always higher. Our conclusion is that the vertical-effect range of temperature of the shelterbelts is 4-10 m, and the humidity range is 6 to 8 m; the horizontal-effect range of temperature is 16 m and the humidity range is about 24 m

Towards versatile access networks (Chapter 3)

Compared to its previous generations, the 5th generation (5G) cellular network features an additional type of densification, i.e., a large number of active antennas per access point (AP) can be deployed. This technique is known as massive multipleinput multiple-output (mMIMO) [1]. Meanwhile, multiple-input multiple-output (MIMO) evolution, e.g., in channel state information (CSI) enhancement, and also on the study of a larger number of orthogonal demodulation reference signal (DMRS) ports for MU-MIMO, was one of the Release 18 of 3rd generation partnership project (3GPP Rel-18) work item. This release (3GPP Rel-18) package approval, in the fourth quarter of 2021, marked the start of the 5G Advanced evolution in 3GPP. The other items in 3GPP Rel-18 are to study and add functionality in the areas of network energy savings, coverage, mobility support, multicast broadcast services, and positionin