Search

Due to the short wavelength of millimeter-wave, active electrical scanning millimeter-wave imaging system requires large imaging scenarios and high resolutions in practical applications. These requirements lead to a large uniform array size and high complexity of the feed network that satisfies the Nyquist sampling theorem. Accordingly, the system faces contradictions among imaging accuracy, imaging speed, and system cost. To this end, a novel, Credible Bayesian Inference of near-field Sparse Array Synthesis (CBI-SAS) algorithm is proposed under the framework of sparse Bayesian learning. The algorithm optimizes the complex-valued excitation weights based on Bayesian inference in a sparse manner. Therefore, it obtains the full statistical posterior Probability Density Function (PDF) of these weights. This enables the algorithm to utilize higher-order statistical information to obtain the optimal values, confidence intervals, and confidence levels of the excitation weights. In Bayesian inference, to achieve a small number of array elements to synthesize the desired beam orientation pattern, a heavy-tailed Laplace sparse prior is introduced to the excitation weights. However, considering that the prior probability model is not conjugated with the reference pattern data probability, the prior model is encoded in a hierarchical Bayesian manner so that the full posterior distribution can be represented in closed-form solutions. To avoid the high-dimensional integral in the full posterior distribution, a variational Bayesian expectation maximization method is employed to calculate the posterior PDF of the excitation weights, enabling reliable Bayesian inference. Simulation results show that compared with conventional sparse array synthesis algorithms, the proposed algorithm achieves lower element sparsity, a smaller normalized mean square error, and higher accuracy for matching the desired directional pattern. In addition, based on the measured raw data from near-field 1D electrical scanning and 2D plane electrical scanning, an improved 3D time domain algorithm is applied for 3D image reconstruction. Results verify that the proposed CBI-SAS algorithm can guarantee imaging results and reduce the complexity of the system.

The monitor lizard (Varanus salvator) has the widest distribution among all extant varanids found across South and Southeast Asia. However, behavioral studies on captive monitor lizard have not been well-documented. The objective of this research was to investigate the effects of enrichment items on the activity and spatial distribution of captive monitor lizards. The study involved three adult captive Black water monitors (Hiea dam), three adult Roughnecked monitors (Ngu-hao Chang), and two adult Dumeril’s monitors (Tut-too) in outdoor enclosures. Three treatments were administered: control (no enrichment item), cone (enrichment item), and takraw (enrichment item: a rattan ball). The frequency of activity and spatial distribution of three species of monitor lizards were recorded. The results showed that the percentages of activity and spatial distribution of three species of monitor lizards were not significantly affected by the enrichment items (P > 0.05). However, there were significant differences only in lying behavior between the Hiea dam, Ngu-hao Chang, and Tut-too monitors (P < 0.05). In conclusion, the general behaviors of captive Hiea dam, Ngu-hao chang, and Tut-too monitor lizards were similar, and their spatial distribution was also similar. The behavior and spatial distribution of captive monitor lizards were not affected by the enrichment items.

Narrow gap submerged arc welding (NG-SAW) and narrow gap tungsten inert gas welding (NG-TIG) with multi-layer and multi-pass techniques were used to join the advanced 9Cr and CrMoV steels. The relationship between the impact toughness and microstructure of the dissimilar welded joint fabricated by these two different welding techniques was systematically investigated. By the impact tests, the results indicated that the average impact energy of the specimen welded by NG-TIG (154.0 J) was five times as high as the one (29.2 J) welded by NG-SAW. Interestingly, an amount of fine second phase particles were detected on the basis of the results. In particular, the precipitates in the welded joint by NG-TIG were much smaller than those by NG-SAW attributing to the faster heat input. Generally, NG-TIG was operated at a faster manufacturing speed, which could lead to a faster cooling of the weld pool and therefore refine the microstructure of the weld. However, no significant differences in the metallographic structure of the whole welded joint could be traced even they suffered different welding techniques. The main microstructure of the WM was tempered martensite in both kinds of specimens. Therefore, the fine dispersed phases could account for the much higher impact toughness of the dissimilar joint prepared by NG-TIG than that via NG-SAW.

The vendors of pet snakes in exhibitions do not use a hide box in their enclosures, so there is a risk of inappropriate handling by customers. This study investigated the effects of enrichment (a hide box) and handling duration (5 and 10 minutes) on the behavior of captive corn snakes (n=8). During period 1 (weeks 1-4), snakes were kept in standard enclosures with sawdust and a water bowl. In period 2 (weeks 5-8), a hide box was added. An instantaneous time and scan sampling observation technique was used. Observations were conducted two hours per week during the 1st -3rd week of each period, recording the general behavior and body postures of the snakes every 5 minutes. In the 4th week of each period, the snakes were handled for 5 minutes on Saturday and 10 minutes on Sunday, with their behavior recorded for 5 minutes post-handling. Results showed that adding a hide box significantly decreased locomotion, digging and soaking (P

The Fe-rich heterogeneous microstructures were observed in the weld metal (WM) of laser welding on dissimilar metals between 9Cr steel and alloy 617, manifesting as vortex-like and lamellar-like structures. They displayed a face-centered cubic structure and consisted of cellular and columnar dendrites. The vortex-like structure was distributed on the upper side of the WM and exhibited the solidification grain boundary. Due to the higher liquid temperature and insufficient mixing, the vortex-like structure exhibited preferential nucleation during the solidification process. On the other hand, the lamellar-like structure was situated on the lower side of the WM and had a thickness of 50 μm. The lamellar-like structure and WM solidified simultaneously with the rapid solidification rate, resulting in noticeable intergranular chemical segregation. During the tensile test, deformation twins formed in the heterogeneous microstructure, due to the lower stacking fault energy and fine particles. Numerous deformation twins played a crucial role in inhibiting crack initiation, which performed the same orientation. Furthermore, the heterogeneous microstructure generated 89.8% of twin boundaries during the crack propagation, while the WM had 30.4%. This phenomenon facilitated plastic energy absorption and deflected the crack propagation path. Thus, the heterogeneous microstructures contributed to the enhancement of mechanical toughness at room temperature.

Abstract Background Atherosclerosis is the pathological basis of cardio-cerebrovascular diseases. Oxidized low-density lipoprotein (ox-LDL) is an important risk factor for atherosclerosis. Ox-LDL leads to endothelial cell (EC) damage and dysfunction through various processes and promotes the occurrence and deterioration of atherosclerosis. High mobility group box-1 (HMGB1) is a protein associated with cellular damage. In the present study, the effect of HMGB1 on ox-LDL-induced EC damage was determined and the underlying mechanism explored. Materials and methods Human umbilical vein ECs (HUVECs) were exposed to ox-LDL to induce endothelial damage and changes in HMGB1 expression level were detected using western blotting analysis and reverse transcription-quantitative PCR. To observe the effect of HMGB1 on ox-LDL-induced damage, the HMGB1 expression was downregulated with siRNA, and cell viability, cytotoxicity, and apoptosis rate were assessed. HUVECs were pretreated with LY294002, an inhibitor of the PI3K/Akt pathway, to determine whether the effect of HMGB1 on damage is via the PI3K-Akt pathway. Results The results showed that ox-LDL can upregulate HMGB1 expression in HUVECs and downregulation of HMGB1 expression can prevent ox-LDL-induced damage in HUVECs. Furthermore, the effect of HMGB1 on ox-LDL-induced damage could be promoted by inhibiting the PI3K/Akt signaling pathway. Conclusion The results indicate HMGB1 may be a promising research target to alleviate ox-LDL-induced EC damage.

The relationship between the microstructure evolution and the corresponding creep rupture performance are systematically investigated. Dramatically enhanced creep rupture performance is achieved for the 9Cr–CrMoV dissimilar welded joint by adjusting the heat treatment process (HTP) of CrMoV steels before welding. The crystallographic structure illustrates that the longer normalizing process could lead to the larger grain size, and the shorter tempering time devotes to the residual lath structure and finer second phase particles. The creep rupture test results show that the welded joint using CrMoV steel with original HTP ruptures in the soft zone with an obvious necking. After adjusting the HTP of CrMoV steel, the creep rupture life increases from 9634 h to 16,108 h accompanied with the rupture location transferred to the weld metal (WM), together with the fracture morphology from dimples to cleavage planes under the same creep rupture parameters. The fracture transition and enhancement of rupture life is resulted from the simultaneous strengthening effect of the lath structure and the precipitated fine particles in the matrix.

Creep rupture behaviors of dissimilar metal welds (DMWs) between Inconel 617B and 10%Cr martensitic steel with two different filler metals Inconel 617 and 82 were comparatively investigated at 600 °C to study the effect of nickel-based filler metal types on creep properties. Both the crept DMWs ruptured on the steel side prematurely compared to steel base metal (BM). The failure mode of DMW shifts from interfacial failure at weld metal (WM)/steel interface to Type Ⅳ crack in the intercritical heat-affected zone (ICHAZ) of steel with longer rupture life at the same creep condition by replacing Inconel 617 filler metal with Inconel 82. Type Ⅳ crack was related to matrix softening and fine prior austenite grain boundaries (PAGBs) scarcely decorated by precipitates in the ICHAZ. Interfacial failure was controlled by creep voids nucleation, growth and coalescence at the interface, while oxide notch only triggered crack initiation. The failure mode shift is because Inconel 82 filler metal compared to Inconel 617 can achieve slighter creep deformation concentration in the HAZ closely adjacent to interface and avoid interfacial failure of the DMW due to the lower creep strength gradient across the interface it induced. Based on this study, creep strength compatibility should be considered when selecting nickel-based filler metals for similar DMWs to obtain prolonged creep life.

Our preliminary study investigated: 1) differences of general behaviors between stereotypic (male, n=2, ST) and non-stereotypic (male, n=2, NST) stabled horses 2) the different reactions to enrichment items (hay nets, bedding straw and yoga ball) between ST and NST horses. The frequency of general behaviors, stereotypic behaviors and the reactions to enrichment items were recorded. The results showed that there was a significantly different frequency of ingestion, locomotion, standing alert, investigation and social interactions between ST and NST horses during 24 hours of observation (P

The weld metal (WM) was generally regarded as one of the weakest zones in the dissimilar welded joints. The microstructure and fracture mechanism of the multi-pass WM are systematically probed in the present study. The scanning electron microscopy (SEM) results show more voids in the equiaxed grain zone (EGZ) adjacent to the fracture than those in the columnar grain zone (CGZ). The transmission electron microscopy (TEM) results reveal that the precipitates are mainly Cr-rich M23C6 and Mo-rich M6C phases. The voids were initiated by the mismatch deformation between the precipitates and matrix during the stress rupture test. Moreover, the voids could easily extend and converge to form the macro cracks in the EGZ.

The potential benefits of music on animals might be through auditory enrichment which modifies the behavior of animals. Our preliminary study focused on using classical music for stabled horses which had stereotypic behaviors. The study was to investigate the effects of playing classical music on the general behaviors of stabled horses (n=4, performed stereotypies) in 5 periods. The 1st period was a 3-day control period during which no music was played. The 2nd, 3rd and 4th periods were 3-day periods of music. The 5th period was for 3 days when no music was played. During the days the classical music was played from 9:00 to 14:00. The behavior of horses was observed from 9:00 to 19:00. The results showed that the frequency of ingestion (P=0.003) and standing alert (P=0.004) during 10 hours observation were affected when music was played. When the periods of music increased, the frequency of ingestion increased. Meanwhile, there was a tendency for the frequency of standing alert to decrease, however, there was no difference in (P>0.05) between the different phases of music. The frequency of standing alert before the period of music was significantly higher (P

OBJECTIVE: The objective of the study was to evaluate the effectiveness and safety of the use of different shunting ways in patients with liver cirrhosis undergoing transjugular intrahepatic portosystemic shunt (TIPS). MATERIALS AND METHODS: We analyzed the data of 36 patients with liver cirrhosis who received de novo TIPS implantation. Sixteen patients had elective TIPS by shunting the blood to the left downstream veins and 20 to the right ones. All patients were followed up for 2 years. We assessed hepatic encephalopathy (HE), rebleeding, and survival rate in all patients post-TIPS. RESULTS: Under our surgical procedure, more post-TIPS HE was observed in the TIPS-left group, whereas rebleeding was detected in the TIPS-right group (P < 0.05). CONCLUSIONS: The decision regarding TIPS placement way for portal hypertension patients needs individualization to allow its safe use, with concomitant improvement in perioperative morbidity.

OBJECTIVE: The objective of the study was to evaluate the role of eosinophil on the outcome and prognosis in stroke patients with pneumonia. PATIENTS AND METHODS: The study included 526 patients with ischemic stroke; the patients were divided into two groups according to whether the patients were complicated with pneumonia or not. All patients were supervised by the National Institutes of Health Stroke Scale (NIHSS) score in 2 weeks. RESULTS: Stroke patients without pneumonia were observed a higher eosinophil count and lower platelet distribution width (PDW) compared to the patients with pneumonia (P < 0.05). Eosinophil counts continued to decrease in patients with pneumonia along with an increasing NIHSS score in 2 weeks. Logistic regression identified dysphagia, eosinophil count, and PDW as predictors of NIHSS scores in poststroke patients with pneumonia. CONCLUSIONS: Our data suggested that eosinophil counts might have a significant role on outcomes in poststroke patients with pneumonia. The results underscored that the interaction between eosinophils and platelets might be a treatment target to improve the outcomes in stroke patients.

Calibration tests are of great importance to ensure rate-sensing accuracy of GyroWheel, an innovative attitude determination and control device. In the process of calibration tests, turntable errors are inevitable, which hinder the calibration accuracy and rate-sensing capability. Hence, error analysis for GyroWheel calibration tests is conducted, and the relationship between the calibration accuracy and the orientation error is established based on analytical derivation and numerical simulations. Subsequently, an error model of the turntable system is derived using rigid body kinematics, by which the relationship between the orientation error and turntable errors is described. According to sensitivity analysis and manufacturing capability, an error allocation method is proposed to determine the accuracy requirement of the test turntable, and the effectiveness of the proposed method is verified by repeated simulation tests. Based on the presented analysis and proposed method in this paper, the effects of various turntable errors on the calibration accuracy can be obtained quantitatively, and a theoretical basis for the determination of the turntable accuracy is provided, which are of great significance to guide the calibration tests and improve the calibration accuracy of GyroWheel.

Studies examining the use of essential oils as replacements for synthetic insecticides require an understanding of the contribution of each constituent present, interactions among these components, and how they relate to overall toxicity. In the present study, the chemical composition of commercial thyme oil was identified by gas chromatography-mass spectrometry. Thyme oil and blends of its major constituents were tested for their acaricidal activitities against carmine spider mites (Tetranychus cinnabarinus (Boisduval)) using a slide-dip bioassay. Natural thyme oil showed greater toxicity than any single constituent or blend of constituents. Thymol was the most abundant component (34.4%), and also possessed the strongest acaricidal activity compared with other single constituents. When tested individually, four constituents (linalool, terpinene, p-cymene and carvacrol) also had activity, while α-pinene, benzoic acid and ethyl gallate had almost no activity. The toxicity of blends of selected constituents indicated a synergistic effect among the putatively active and inactive constituents, with the presence of all constituents necessary to reach the highest toxicity. The results indicated that thyme oil and some of its major constituents have the potential to be developed into botanical acaricides.

GyroWheel is an integrated device that can provide three-axis control torques and two-axis angular rate sensing for small spacecrafts. Large tilt angle of its rotor and de-tuned spin rate lead to a complex and non-linear dynamics as well as difficulties in measuring angular rates. In this paper, the problem of angular rate sensing with the GyroWheel is investigated. Firstly, a simplified rate sensing equation is introduced, and the error characteristics of the method are analyzed. According to the analysis results, a rate sensing principle based on torque balance theory is developed, and a practical way to estimate the angular rates within the whole operating range of GyroWheel is provided by using explicit genetic algorithm optimized neural networks. The angular rates can be determined by the measurable values of the GyroWheel (including tilt angles, spin rate and torque coil currents), the weights and the biases of the neural networks. Finally, the simulation results are presented to illustrate the effectiveness of the proposed angular rate sensing method with GyroWheel.

The problem of packing spheres in Orlicz sequence space lΦ,p equipped with the p-Amemiya norm is studied, and a geometric characteristic about the reflexivity of lΦ,p is obtained, which contains the relevant work about lp (p>1) and classical Orlicz spaces lΦ discussed by Rankin, Burlak, and Cleaver. Moreover the packing constant as well as Kottman constant in this kind of spaces is calculated.

GyroWheel is an innovative device that combines the actuating capabilities of a control moment gyro with the rate sensing capabilities of a tuned rotor gyro by using a spinning flex-gimbal system. However, in the process of the ground test, the existence of aerodynamic disturbance is inevitable, which hinders the improvement of the specification performance and control accuracy. A vacuum tank test is a possible candidate but is sometimes unrealistic due to the substantial increase in costs and complexity involved. In this paper, the aerodynamic drag problem with respect to the 3-DOF flex-gimbal GyroWheel system is investigated by simulation analysis and experimental verification. Concretely, the angular momentum envelope property of the spinning rotor system is studied and its integral dynamical model is deduced based on the physical configuration of the GyroWheel system with an appropriately defined coordinate system. In the sequel, the fluid numerical model is established and the model geometries are checked with FLUENT software. According to the diversity and time-varying properties of the rotor motions in three-dimensions, the airflow field around the GyroWheel rotor is analyzed by simulation with respect to its varying angular velocity and tilt angle. The IPC-based experimental platform is introduced, and the properties of aerodynamic drag in the ground test condition are obtained through comparing the simulation with experimental results.

Microplastic is globally regarded as an important factor impacting biogeochemical cycles, yet our understanding of such influences is limited by the uncertainties of intricate microbial processes. By multiomics analysis, coupled with soil chemodiversity characterization and microbial carbon use efficiency (CUE), we investigated how microbial responses to microplastics impacted soil carbon cycling in a long-term field experiment. We showed that biodegradable microplastics promoted soil organic carbon accrual by an average of 2.47%, while nondegradable microplastics inhibited it by 17.4%, as a consequence of the virus-bacteria coadaptations to the microplastics disturbance. In the relevant functional pathways, nondegradable microplastics significantly (P < 0.05) enhanced the abundance and transcriptional activity related to complex carbohydrate metabolism, whereas biodegradable microplastics significantly (P < 0.05) promoted functions involved in amino acid metabolism and glycolysis. Accordingly, viral lysis enhanced in nondegradable microplastics treatments to introduce more complex organic compounds to soil dissolved organic matters, thus benefiting the oligotrophs with high carbon metabolic capabilities in exploitation competition. In contrast, biodegradable microplastics enriched viral auxiliary metabolic genes of carbon metabolism through "piggyback-the-winner" strategy, conferring to dominant copiotrophs, enhanced substrate utilization capabilities. These virus-host interactions were also demonstrated in the corresponding soil plastisphere, which would alter microbial resource allocation and metabolism via CUE, affecting carbon storage consequently. Overall, our results underscore the importance of viral-host interactions in understanding the microplastics-dependent carbon storage in the soil ecosystem. [ABSTRACT FROM AUTHOR]