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We have developed a methodology for the greatly efficient construction of significant 2,3-dihydrobenzofuran scaffolds bearing a quaternary carbon center at the C2 position by means of [4 + 1] annulation reactions between p-quinone methides and α-aryl diazoacetates as C1 synthons through organocatalysis by readily accessible TfOH catalyst under mild and transition metal-free conditions. This metal-free protocol furnishes an operationally simple and swift process for the free assembly of diverse highly functionalized 2,3-dihydrobenzofurans and also features broad substrate scope, excellent functional group compatibility, and environmental friendliness. Mechanistic investigation suggested that the reaction undergoes a rapid cascade protonation/intermolecular Michael addition/intramolecular substitution process.

Silicon carbide (SiC) is regarded as a promising semiconductor owing to its wide band gap and high thermal conductivity. Meanwhile, it possesses issues such as interface properties, which may affect the performance of SiC substrate power devices (e.g. MOSFET), especially when compared with similarly structured silicon appliances. Given that the development of SiC semiconductor devices has a number of commonalities with conventional silicon-based semiconductors, titanium dioxide (TiO2), a material that has a great track record in Si-based semiconductor devices, has been chosen for investigation in this work. Although TiO2 is not capable of being a gate dielectric alone on the SiC substrate because of its relatively narrow band gap, it can be adopted into composite or multilayer gate dielectrics to reach satisfying characteristics. As such, the interfacial state and heterostructure between TiO2 and SiC remain worthy being researched. In the present study, the properties of atomic layer deposited (ALD) TiO2 films on silicon substrates were compared with those on 4H-SiC substrates via x-ray photoelectron spectroscopy, atomic force microscopy, and x-ray reflectometry. It is shown that the interface state between ALD TiO2 film and both types of substrates as-deposited have similar chemical conditions, whereby TiO2 layer barely react with substrates, containing great amount of oxygen vacancies. According to band alignment calculations, heterostructure of both samples are type-II heterojunctions with negatively shifted conduction band. Although the large bandwidth of 4H-SiC hinders the use of TiO2 as a gate dielectric in power devices, this structure has the potential for other semiconductor products.

In this study, a higher metal ions-resistant bacterium, Stenotrophomonas rhizophila JC1 was isolated from contaminated soil in Jinchang city, Gansu Province, China. The Pb2+ (120 mg/L) and Cu2+ (80 mg/L) removal rate of the strain reached at 76.9% and 83.4%, respectively. The genome comprises 4268161 bp in a circular chromosome with 67.52% G + C content and encodes 3719 proteins. The genome function analysis showed czc operon, mer operon, cop operon, arsenic detoxification system in strain JC1 were contributed to the removal of heavy metals. Three efflux systems (i.e., RND, CDF, and P-ATPase) on strain JC1 genome could trigger the removal of divalent cations from cells. cAMP pathway and ABC transporter pathway might be involved in the transport and metabolism of heavy metals. The homology analysis exhibited multi-gene families such as ABC transporters, heavy metal-associated domain, copper resistance protein, carbohydrate-binding domain were distributed across 410 orthologous groups. In addition, heavy metal-responsive transcription regulator, thioredoxin, heavy metal transport/detoxification protein, divalent-cation resistance protein CutA, arsenate reductase also played important roles in the heavy metals adsorption and detoxification process. The complete genome data provides insight into the exploration of the interaction mechanism between microorganisms and heavy metals.

For the first time, this research addresses the notable layout proximity effects induced by stress memorization technique in planer high-k/Metal gate NMOS device systematically, including width effect, different shallow trench spacing effect, and length of diffusion effect. Based on the oxygen diffusion mechanism analysis of layout proximity effects in high-k/Metal gate NMOS device, an optimized process is proposed to suppress the layout dependency. The experiment result indicates that modified low temperature stress memorization technique process can suppress layout dependency efficiently without performance degradation of the devices.

The dinoflagellate genus Alexandrium comprises most of the toxic bloom-forming species producing paralytic shellfish toxins (PSTs) in the sea. Recently, repeated paralytic shellfish poisoning episodes have been recorded in Qinhuangdao located at the west coast of the Bohai Sea. To elucidate the relationship between toxic Alexandrium blooms and the poisoning episodes, a year-round investigation was carried out in this region from July 2020 to July 2021. Two qPCR assays were used to detect A. catenella and A. pacificum, and LC-MS/MS was applied to analyze PSTs in phytoplankton and shellfish samples. The blooms of A. catenella and A. pacificum were found in April and July, respectively, and PST content in three bivalves exhibited notable increase following the bloom of A. catenella. The results revealed bloom dynamics of the two toxic Alexandrium species in the Bohai Sea for the first time, and further confirmed A. catenella as the causative agent of poisoning episodes.

Phaeocystis globosa has formed intensive blooms in the South China Sea and even around the world, causing huge social economic losses and environmental damage. However, little is known about the formation mechanism and dynamics of P. globosa blooms. 19′-Hexanoyloxyfucoxanthin (hex-fuco) is often used as the pigment proxy to estimate Phaeocystis biomass, while this is challenged by the giant-colony-forming P. globosa in the Beibu Gulf, which contains only 19′-butanoyloxyfucoxanthin (but-fuco) but not hex-fuco.

Since 1990s, harmful algal blooms (HABs) of Kareniaceae, primarily caused by species of Karenia and Karlodinium and rarely by Takayama species, have been substantially increasing in frequency and duration in the coastal waters of China. In this study, we recorded a bloom of high abundance of T. acrotrocha in the Haizhou Bay, the Yellow Sea in September 2020, which is the first record of a Takayama bloom in the temperate coastal waters of China. We found that high concentrations of DON and DOP accelerated the proliferation of T. acrotrocha in the Haizhou Bay. Intensive mariculture, and terrestrial nitrogen and phosphorus input may be responsible for the eutrophication in the Haizhou Bay featuring high concentrations of DON and DOP, and high DIN/DIP ratios. The results suggested that, under ocean warming, the HABs of Kareniaceae are becoming increasingly dominant in eutrophic temperate coasts with intensive mariculture activities.

The giant-colony-forming haptophyte Phaeocystis globosa has caused several large-scale blooms in the Beibu Gulf since 2011, but the distribution and dynamics of the blooms remained largely unknown. In this study, colonies of P. globosa, as well as membrane-concentrated phytoplankton samples, were collected during eight cruises in the Beibu Gulf from September 2016 to August 2017. Pigments were analyzed by high-performance liquid chromatography coupled with a diode array detector (HPLC-DAD). The pigment 19′-hexanoyloxyfucoxanthin (hex-fuco), generally considered a diagnostic pigment for Phaeocystis, was not detected in P. globosa colonies in the Beibu Gulf, whereas 19′-butanoyloxyfucoxanthin (but-fuco) was found in all colony samples. Moreover, but-fuco in membrane-concentrated phytoplankton samples exhibited a similar distribution pattern to that of P. globosa colonies, suggesting that but-fuco provided the diagnostic pigment for bloom-forming P. globosa in the Beibu Gulf. Based on the distribution of but-fuco in different water masses in the region prior to the formation of intensive blooms, it is suggested that P. globosa blooms in the Beibu Gulf could originate from two different sources. IMPORTANCE Phaeocystis globosa has formed intensive blooms in the South China Sea and even around the world, causing huge social economic losses and environmental damage. However, little is known about the formation mechanism and dynamics of P. globosa blooms. 19′-Hexanoyloxyfucoxanthin (hex-fuco) is often used as the pigment proxy to estimate Phaeocystis biomass, while this is challenged by the giant-colony-forming P. globosa in the Beibu Gulf, which contains only 19′-butanoyloxyfucoxanthin (but-fuco) but not hex-fuco. Using but-fuco as a diagnostic pigment, we traced two different origins of P. globosa blooms in the Beibu Gulf. This study clarifies the development process of P. globosa blooms in the Beibu Gulf, which provides a basis for the early monitoring and prevention of the blooms.

The haptophyte Phaeocystis globosa, an important causative agent of harmful algal blooms globally, exhibits varying morphological and physiological features and high genetic diversity, yet the relationship among these has never been elucidated. In this study, colony sizes and pigment profiles of 19 P. globosa isolates from the Pacific and Atlantic Oceans were determined. Genetic divergence of these strains was analyzed using the chloroplast rbcS-rpl27 intergenic spacer, a novel high-resolution molecular marker. Strains could be divided into four genetic clades based on these sequences, or two groups based on colony size and the identity of diagnostic pigments (19'-hexanoyloxyfucoxanthin, hex-fuco, and 19'-butanoyloxyfucoxanthin, but-fuco). Three strains from the South China Sea (SCS), all belonging to the same genetic clade, have unique biological features in forming giant colonies and possessing but-fuco as their diagnostic pigment. Based on these findings, we propose that these SCS strains should be a unique "giant-colony" ecotype of P. globosa. During the period 2016-2021, more than 1000 rbcS-rpl27 sequences were obtained from 16 P. globosa colony samples and 18 phytoplankton samples containing solitary P. globosa cells in the SCS. Phylogenetic analysis indicated that95% of the sequences from P. globosa colonies in the SCS were comprised of the "giant-colony" ecotype, whereas the genetic diversity of solitary cells was much higher. Results demonstrated that intense blooms of P. globosa featuring giant colonies in the SCS were mainly caused by this giant-colony P. globosa ecotype.

In this study, a higher metal ions-resistant bacterium, Stenotrophomonas rhizophila JC1 was isolated from contaminated soil in Jinchang city, Gansu Province, China. The Pb

Dinoflagellate Gymnodinium catenatum is an important producer of paralytic shellfish toxins (PSTs), including a novel group of hydroxybenzoate derivatives named GC toxins. In the East China Sea, G. catenatum has been considered as the causative agent for several paralytic shellfish poisoning (PSP) episodes, yet the knowledge on their toxin production was still quite limited. In this study, toxins produced by a strain of G. catenatum (MEL11) isolated from the East China Sea were determined, using high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). Changes of toxin profile in the stain MEL11 in response to nutrient and temperature variations were also examined. A total of 11 PST components dominated by hydroxybenzoate analogs and N-sulfocarbamoyl toxins were detected, which was different from other G. catenatum strains previously established in the East China Sea in the presence of GC5 and the lack of dcGTX23. Cellular toxin composition and content of the strain had no apparent change within a range of temperature from 20°C to 26°C. In contrast, nutrient limitation and nitrogen source had notable impacts on toxin production. The molar percentage of GC toxins decreased remarkably at the stationary growth phase under nutrient-deprived conditions of both nitrogen (N) and phosphorus (P). The replacement of nitrate with ammonium as the source of N significantly promoted PST production by G. catenatum. The study revealed the potential diversity of toxin profiles of G. catenatum in the East China Sea, and highlighted the effects of nutrients on production of GC toxins by G. catenatum.

Two new steroidal alkaloids, 23-methoxycyclopamine 3-O-β-D-glucopyranoside (1) and isoecliptalbine (2), were isolated from the root and rhizoma of Veratrum maackii Regel, together with five known compounds, i.e., verussurine (3), verabenzoamine (4), verazine (5), isoverazine (6), and verazinine (7). Their structures were established by extensive analysis of spectroscopic data, as well as by comparison with literature data. Compounds 1–7 could cause DNA damage in the cerebellum and cerebral cortex of mice in a dose-dependent manner by using single-cell gel electrophoresis (comet assay).

Two new steroidal alkaloids, 2β-hydroxyverdine (1) and tomatillidine 3-O-β-D-glucopyranoside (2), were isolated from the root and rhizome of Veratrum dahuricum (Turcz.) Loes. f., together with four known compounds, i.e., 16-O-(2-methylbutyroyl)germine (3), veramitaline (4), jervine (5), and veratroylzygadenine (6). Their structures were established by extensive spectroscopic analysis, as well as by comparison with data in literature. Compounds 1–6 exhibited genotoxicity on brain cell DNA of the cerebellum and cerebral cortex in mice, evaluated by using single-cell gel electrophoresis (comet assay).

Based on molecular dynamics method, the tensile process of single crystalline Cu nanorod and single crystalline Cu bulk were simulated at atomic scale. The motion of atoms, total energy of atom-strain curves and number of dislocation atom-strain curves during the tensile process were acquired. The results shown that surface effect has a significant effect on the tensile mechanical properties of single crystalline Cu nanorod. For single crystalline Cu nanorod, the energy of atoms in the edges and surface were higher than the energy of atoms inside the nanorod. Dislocations nucleation in the edges that with high energy and extend along the {111} crystal plane. The nanorods produce plastic deformation and shows excellent ductility under the "dislocation nucleation-energy rising and dislocation layers cross-slip" mechanism of the alternating cycle. For single crystalline Cu bulk, dislocation nucleation randomly and extend to the entire simulation model along the {111} crystal plane quickly. The single crystalline bulk Cu produce fracture under the "microscopic vacancy-microscopic hole-penetration of microscopic holes-fracture" mechanism.

Metabolism study was carried out on 12 β -hydroxylveratroylzygadenine (VOG) that is a cevine-type alkaloid existing in Veratrum nigrum L. and a neurotoxic component. In order to better understand the potential mechanism of neurotoxicity of VOG, this study measured VOG-induced DNA damage in the cerebellum and cerebral cortex of mice after 7 days repetitive oral dose by using single-cell gel electrophoresis (Comet assay). High performance liquid chromatography-tandem mass spectrometry (LC–MS/MS) was developed and applied to separate and identify in vitro and in vivo metabolites of VOG for investing the possible relationship of metabolism and neurotoxicity. In vitro experiment was carried out using rat liver microsomes, while the in vivo study was conducted on rats. The obtained results indicated that VOG might cause DNA damage in cerebellum and cerebral cortex of mice in a dose-dependent manner. Hydrolysis of ester bond and O -demethylation were proposed to be the main in vivo metabolic pathways of VOG, while the major in vitro metabolic pathways were proposed as methyl oxidation to aldehyde, dehydrogenation, hydrolysis of ester bond, hydrolysis of ester bond together with acetylation, and methoxylation. O -Demethylation reaction was likely to be associated with reactive oxygen species production, leading to the DNA damage.

Based on the status of tower crane safety monitoring for construction project, the Internet of things technology is applied for tower crane safety monitoring and early warning system, the WSN nodes are designed for displacement, stress and distance monitoring function. Through the wireless transceiver module CC2530, field monitoring data are uploaded timely and accurately to the monitoring center PC, for real-time display and processing. If the monitoring data exceeds the alarm value, the alarm signal will be sent out immediately, to prevent tower crane accidents effectively, and ensure the safe of crane operation. By the network debugging, WSN node performance is reliable, and the measuring data is accurate. It has high performance to price ratio and application value.

Two-dimensional finite element model is established by ABAQUS Explicit finite element analysis in this paper. It includes abrasive wear micro cutting process between pair of guide. Johnson-cook constitutive model is used to simulate the guide material deformation of wear process. Based on different sizes and different speed of grain, loading, cutting and unloading process are simulated by finite element, guide surface stress distribution and deformation condition are studied in the guide rail pair wear process. The simulation data is obtained by central composite experiments and regression model is gotten by MATLAB. The influence law of the particle radius and speed to guide residual compressive stress and deformation are gotten by the prediction model.

According to general piezoelectric acceleration sensor measurement circuit existing problems in the dynamic testing field, the paper proposes the modular, integration design method, using the integrated chips CA3140 to design the signal disposal circuit, in order to reduce the cost and improve the circuit SNR, enhance the stability and reliability of the circuit. This circuit includes a charge amplifier, conditional amplifier, low-pass filter, high-pass filter and output amplifier. The test shows that the circuit functions are complete, it is practical and reliable. It has a higher performance price ratio, and can be widely used in the dynamic monitoring and the diagnosis of fault or defect about the equipment and structure.

To overcome the difficult in modeling the mode theory for magnetic flywheel, by non-parametric frequency domain identification method for identification of system model, this paper select the PID neural network nonlinear intelligent control methods based on GA. Used a method based on iterative process to suppress the resonance, combined with zero-pole theory, this research designed a GA-based PID neural network identification controller to address the modal vibration suppression problems in the external rotor flywheel .The experiments for this paper proved the effectiveness of iterative process, and the controller can restrain the system mode vibration well.

The magnetic flywheel is widely used in energy storage and spacecraft, and it needs to reduce the system’s power consumption effectively when designing the controller. Always, the magnetic bearing system’s performance depends on the tracking performance of the desired force signal. In order to balance the two goals between reducing magnetic system’s power consumption and guaranteeing its performance, a current power allocation way was proposed, and a static current optimization was given based on the way. According to the simulation and experimental results, this method can reduce the magnetic bearing system’s power consumption significantly and keep the tracking performance of force signal well on the same time.

Electric vehicle is an important developing trend of the vehicle industry and the power and technique field. But nowadays, there still exist some problems in this field which cant be solved with mature solutions, such as long time of charging, high cost of replacing and charging station and large areas it covers, low efficiency and so on. By building an effective model, this paper brings up a conceptual design of an automatic system of replacing and charging batteries for electric vehicles with the late-model design of the multi-station device. By observing the effect of the experimental device, it can solve the problems mentioned above, but more should be done to improve it. This design, the demo system, mainly includes electric vehicle model system, replacing and charging station system and GPS navigation system, and it performs excellent in experiment.

According to the characteristics of jumping locomotion, a solution of Tetra-state Hopping Robot (for short: THR) actuated by Shape Memory Alloy Spring (for short: SMAS) is presented in this paper. This article establishes a mechanical model of the jumping robot and analyzes the kinematics and the dynamics of the mechanical model. Lagrange method is applied to analyze the dynamics the mechanical model. Meanwhile, a preliminary explanation of the THR flipping phenomenon during the take-off and flight process is conducted from the perspective of momentum moment.

There are a lot of dynamic changing problems for design version in the complex product design process. We have study a dynamic version control technology for result it. Firstly, we have researched the three level version control model, including the complex product structure layer, the node version tree layer and the version structure layer. Secondly, we have researched the version control model operations, including the version structure operations and the version operations, and analyzed the implementation of the version generation function and the version mergence function. Finally, the method has been applied and verified in the development of an aircraft flight loads integrated design platform.

An idea of self-helpingly exchanging and charging batteries is proposed to solve some Battery Exchanging and Charging (BEC, for short) problems of Electric-Networked Vehicles (short for, EN-V). Large scale BEC stations occupy large working area and need high equipment cost; common charge piles have disadvantages of long charging time. As a result, a physical demonstration system, which encompasses intelligent vehicle system, BEC stake system and GPS (Global Positioning System) simulation system, is established to validate the feasibility of the idea.

Screw thread, as the most basic and widely used mechanic element, has many traditional methods to verify its dimension consistency. Machine vision technology is gradually applied to inspect screw thread in fastener industry because of its fast, precise and repeatable features. Based on analysis of the features and problems of previous vision measurement methods, this paper provides calculation, analysis and simulation of screw thread’s 3D mathematic model, and finally provides corresponding algorithm to correct calculation error resulting from shading effect of backlight projecting.

Based on the principle of axial active magnetic bearing rotor-system with single degree of freedom, magnetic rotor-system vibration mode was described. A 3D finite element model of active magnetic bearing rotor-system was established by ANSYS11. Initial six order natural frequencies and vibration mode were calculated by the module of modal analysis of ANSYS11, and compared with the results of system identification. Analysis shows that there was a certain difference between the results, but the difference was small. The analysis result indicates that it is an effective method to apply FEA in the design of the active magnetic bearing. It provided the foundation for structure optimal design of the system and theoretical basis for flexible system design.

In order to overcome the system nonlinear instability and uncertainty inherent in magnetic bearing systems, two PID neural network controllers (BP-based and GA-based) are designed and trained to emulate the operation of a complete system. Through the theoretical deduction and simulation results, the principles for the parameters choice of two neural network controllers are given. The feasibility of using the neural network to control nonlinear magnetic bearing systems with un-known dynamics is demonstrated. The robust performance and reinforcement learning capability in controlling magnetic bearing systems are compared between two PID neural network controllers.

Background/PurposeChronic rejection limits the long-term success of cardiac transplantation and the underlying cause of the disease is unknown. Connective tissue growth factor (CTGF) is considered as a mitogenic and chemotactic factor for fibroblasts, and is associated with cell proliferation and collagen synthesis. We evaluated the expression of CTGF in a rat model of heart allograft chronic rejection.MethodsIntra-abdominal heterotopic heart transplantation was performed from 20 Wistar rats to 20 Sprague–Dawley (SD) rats that received cyclosporine, mycophenolate mofetil and methylprednisolone as immunosuppression. Ten heart allografts were explanted at 2 and 8 weeks postoperatively for analysis of morphologic changes. The hearts from 10 normal Wistar rats served as a control group. Coronary artery density, luminal loss of myocardial coronary arteries, and myocardial fibrosis were measured. The expression of CTGF was studied by immunohistochemistry. Correlation between CTGF expression and development of cardiac allograft vasculopathy (CAV) or fibrosis was studied.ResultsAllografts harvested at 8 weeks postoperatively showed more coronary intimal proliferation, fibrosis and CTGF expression compared with the 2-week allografts (p < 0.05) and the controls (p < 0.01), but the coronary artery density was lower than in the control group (p < 0.05). However, the control group showed negligible CTGF expression. There were strong negative correlations between the gray value of CTGF protein expression and cardiac fibrosis and coronary intimal occlusion (r = −0.734, −0.713; p < 0.01), which demonstrated that CTGF protein expression was positively correlated with cardiac fibrosis and coronary intimal occlusion.ConclusionCTGF is expressed in cardiomyocytes in CAV. Increased expression of CTGF in cardiac allografts is associated with development of CAV and fibrosis formation.

Two new steroidal alkaloids (I) and (II) are isolated from the root and rhizoma of Veratrum maackii together with five known compounds.

Two new steroidal alkaloids, 2β-hydroxyverdine (1) and tomatillidine 3-O-β-D-glucopyranoside (2), were isolated from the root and rhizome of Veratrum dahuricum (Turcz.) Loes. f., together with four known compounds, i.e., 16-O-(2-methylbutyroyl)germine (3), veramitaline (4), jervine (5), and veratroylzygadenine (6). Their structures were established by extensive spectroscopic analysis, as well as by comparison with data in literature. Compounds 1–6 exhibited genotoxicity on brain cell DNA of the cerebellum and cerebral cortex in mice, evaluated by using single-cell gel electrophoresis (comet assay).