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

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

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%

Elastic wave confinement and absorption in a dissipative metamaterial

In this paper, we report on the theoretical investigation of the elastic wave confinement and absorption in a dissipative metamaterial, which is constituted of two-dimensional phononic crystals with binary composite material defect composed of aluminum discs hemmed around by damped rubber. Based on an efficient finite element method in combination with a super cell technique, the dispersion relations and the power transmission spectra of the proposed dissipative metamaterialshave been calculated. Numerical results show that the proposed dissipative metamaterials can yield complete band gap as well as defect states. Elastic waves of the specific frequency of the defect models in the range of gap frequencies have been confined and dissipated simultaneously in the point defect or along the line defects. In contrast to the traditional damper for vibration energy dissipation, the proposed dissipative metamaterials can be equivalent to elastic wave energy attractor and possess significant higher energy dissipation rate for ambient distributed vibration. These elastic wave confinement and dissipation properties of the proposed dissipative metamaterials can potentially be utilized to generate vibration absorbers as well as optimization design of damped structure

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.

Fenugreek Prevents the Development of STZ-Induced Diabetic Nephropathy in a Rat Model of Diabetes

The present study aims to examine the protective effect of fenugreek and the underlying mechanism against the development of diabetic nephropathy (DN) in streptozotocin- (STZ-) induced diabetic rats. A rat model of diabetes was successfully established by direct injection of STZ and then the rats were administered an interventional treatment of fenugreek. Parameters of renal function, including blood glucose, albuminuria, hemoglobin A1c (HbA1c), dimethyl formamide (DMF), blood urine nitrogen (BUN), serum creatinine (Scr), and kidney index (KI), were detected in the three groups (Con, DN, and DF). Oxidative stress was determined by the activity of antioxidase. Extracellular matrix (ECM) accumulation and other morphological alterations were evaluated by means of immunohistochemistry and electron microscope. Quantitive (q)PCR was employed to detect the mRNA expression of transforming growth factor-β1 (TGF-β1) and connective tissue growth factor (CTGF) and protein expression was determined with western blot analysis. DN rats in the present study demonstrated a significant renal dysfunction, ECM accumulation, pathological alteration, and oxidative stress, while the symptoms were evidently reduced by fenugreek treatment. Furthermore, the upregulation of TGF-β1 and CTGF at a transcriptional and translational level in DN rats was distinctly inhibited by fenugreek. Consequently, fenugreek prevents DN development in a STZ-induced diabetic rat model.</jats:p

Clinical characteristics and genetic mutation analysis in 18 pediatric patients with Shwachman-Diamond syndrome

PurposeTo investigate the clinical features and genetic mutation spectrum of 18 children with Shwachman-Diamond syndrome (SDS).MethodsData from 18 children with SDS at Shandong University Affiliated Children’s Hospital (Ji’nan Children’s Hospital) between April 2016 and June 2024 were retrospectively analyzed. Variant sites were confirmed by Sanger sequencing in family lines.ResultsPatients exhibited complex and diverse clinical symptoms, often involving multiple systems. The clinical features of this cohort included (1) early onset (median age: 1.5 months), diarrhea, trypsin reduction, neutropenia, and growth retardation and (2) high incidence of pancreatic imaging abnormalities, bone marrow hypoplasia, developmental malformations, and neurocognitive disorders. All patients had homozygous or compound heterozygous SBDS mutations, with 258+2T&gt;C identified as the hotspot mutation (20/37), while 41A&gt;T and 185A&gt;C were newly discovered mutations.ConclusionPatients with SDS exhibit clinical heterogeneity, and this study enriches the SBDS gene mutation spectrum. Genetic testing is valuable for early diagnosis