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Both climate warming and litter removal alter soil nematode communities and the structure, stability, and function of soil food webs. The soil nematode metabolic carbon footprint, based on nematode biomass and respiration, can be used to indicate ecosystem function and the response of nematodes to nutrient enrichment in the ecosystem. However, it is unclear whether or how climate warming and litter removal affect the metabolic carbon footprint of soil nematodes and soil food webs. In this study, we investigated four warming and litter removal treatments in the Qinghai-Tibet Plateau, China, to determine the effects of climate warming and litter removal on soil microbial food webs. The treatments included: (1) control (CK), (2) warming, (3) litter removal, (4) warming + litter removal. We found that warming and litter removal had significant negative effects on the diversity and richness of soil nematodes. In addition, our results showed warming indirectly and directly affected vegetation diversity, thereby altering soil nematode diversity. Vegetation played an important role in the maintenance of soil nematode community diversity. The enrichment and structural footprints reflected nematodes that could respond most rapidly to resource enrichment and those with higher trophic levels in soil food webs, respectively. Overall, warming and litter removal significantly negatively affect the enrichment metabolic footprint, indicating they could significantly reduce the external resource inputs into the food web. Both warming and litter removal reduced the structural metabolic footprint of the soil food web, although the changes were not significant, indicating that the metabolic activity of nematodes of high nutrient levels decreased and the ability to regulate the food web from top-bottom effects was weakened under warming and litter removal. The nematode functional metabolic footprints indicated that litter removal could aggravate the effect of warming on the soil food web and result in more severe degradation. The combination of warming and litter removal significantly inhibited the connectance of the bacterial channel, but had no significant effect on the fungal channel. These results suggest that the soil food web enhanced resistance to the environment by increasing the proportion of the fungal channel. It is critical to understand the responses of soil food webs to climate warming and litter removal to better predict how ecosystem functions will change in the future.

Thermoelectrics is attractive as a green and sustainable way for harnessing waste heat and cooling applications. Designing high performance thermoelectrics involves navigating the complex interplay between electronic and heat transports. This fundamentally involves understanding the scattering physics of both electrons and phonons, as well as maximizing symmetry-breaking in entropy and electronic transports. In the last two decades, thermoelectrics have progressed in leaps and bounds thanks to parallel advancements in scientific technologies and physical understandings. Figure of merit zT of 2 and above have been consistently reported in various materials, especially Chalcogenides. In this review, we provide a broad picture of physically driven optimization strategies for thermoelectric materials, with emphasis on electronic transport aspect of inorganic materials. We also discuss and analyzes various newly coined metrics such as quality factors, electronics quality factor, electronic fitness function, weighted mobility, and Fermi surface complexity factor. More importantly, we look at the non-trivial interdependencies between various physical parameters even at a very fundamental level. Moving forward, we discuss the outlook for the potential of 3D printing and device oriented research in thermoelectrics. The intuition derived from this review will be useful not only to guide materials selection, but also research directions in the coming years.

To explore the prognostic value of Ki-67 and p53 in patients with head and neck mucosal melanoma by analyzing the relevant data from previous patients.Data on Ki-67 and p53 immunohistochemical staining in 128 patients treated in Beijing Tongren Hospital between April 2005 and January 2021 were analyzed retrospectively. The correlation of Ki-67 and p53 expression with general clinical features and survival prognosis was analyzed.Median follow-up time was 21 months. There were 66 cases in the group with Ki-67 40% and 62 cases in the group with Ki-67 ≥ 40%, with 60 cases in the p53-negative group and 68 cases in the p53-positive group. Of the 128 patients, 67 died and 61 survived. There were 63 patients with distant metastasis and 33 patients with local recurrence. Ki-67 expression was related to distant metastasis but this was not an independent risk factor; however, it was an independent risk factor affecting the survival of patients. The survival time for patients with Ki-67 ≥ 40% was significantly shorter than for patients with Ki-67 40%. P53 expression had no significant effect on survival and prognosis.Ki-67 is related to the disease stage and overall survival of patients with head and neck mucosal melanoma. It may have a guiding significance for the prognosis of patients as those with higher Ki-67 levels had poorer prognosis. However, the incidence rate of this disease is low, and all of the results need to be verified with a larger dataset.

In this study, a subset simulation-based methodology is developed to evaluate the time-dependent reliability of the corroding pipeline with multiple correlated corrosion defects. Two competing failure modes, namely small leak and burst, are considered in the methodology. Firstly, the time-dependent structural reliability model of the two competing failure modes is established. Then, the computational framework for implementing subset simulation for failure probability estimation of the individual corrosion defect is presented. Thereafter, a procedure to calculate the system reliability of the entire pipeline with correlated corrosion defects is proposed. Moreover, a numerical example based on a real natural gas pipeline is proposed, and the time-dependent failure probabilities of both the small leak and burst are predicted, which are compared with the evaluation results produced by the direct Monte Carlo simulation and Kriging method. By means of numerical example, the accuracy and efficiency of our methodology are demonstrated. Furthermore, a sensitivity analysis is performed to investigated the effect of the correlation of the corrosion defects on the system reliability, and the results indicate that the correlation exert great impact on system reliability.

The fluctuation characteristics of the gas demand and the effect of the user importance are usually ignored in previous gas supply reliability research. With the intent of overcoming these deficiencies, an integrated method based on the demand-side analysis is proposed in this study to assess the gas supply reliability of the large-scale and complex natural gas pipeline network. The method is composed of the establishment of the indicator system, the demand-side analysis, the estimation of the unit failure probability, and the calculation of the gas supply. Among them, the demand-side analysis focuses on the market demand forecasting and user importance research. Moreover, the coupling effect of the user importance, the hydraulic and pressure constraints, and the unit failure on the gas supply calculation is considered. Furthermore, a real natural gas pipeline network located in China is applied to confirm the feasibility of the method. According to the evaluation results of the gas supply reliability, the weakest nodes and key links of the natural gas pipeline network are identified, and the suggestions to improve the gas supply reliability are proposed as well. At last, the significance of the demand side in the gas supply reliability is elaborated and validated.

This paper presents an ultra-low noise L-band radio astronomical cryogenic receiver for FAST telescope. The development of key low noise microwave parts of Coupling-LNA and conical quad-ridge OMT and reasonable system integration achieve outstanding performance of receiver.It covers the frequency range of 1.2 GHz to 1.8 GHz. Novel cryogenic Coupling-LNAs with low noise, large return loss, high dynamic range and the function of coupling calibration signals are developed for the proposed receiver.Amplification and coupling function circuits are integrated as a single Coupling-LNA with full noise temperature of 4 K at the physical temperature of 15 K. And its return loss is more than 18 dB, and output 1 dB compression power is +5 dBm. A cryogenic dewar is fabricated to provide 55 K and 15 K cryogenic environment for OMT and Coupling-LNAs, respectively. The receiver's system noise temperature is below 9 K referred to feed aperture plane. Benefiting from optimal design and precise mechanical treatment, good scattering performance of OMT and equalized radiation patterns of horn are achieved with an antenna efficiency above 75%., Comment: There are 20 pages and 24 figures

The Five-hundred-meter Aperture Spherical radio Telescope (FAST) located in Guizhou, China, is a very sensitive single dish telescope. Due to the large size of the telescope, optical fiber is used for the transmission of the 3-km astronomical signal from the telescope to the signal processing center. The optical fibers are suspended in the air above the telescope reflector, very easy to slide when the telescope feed cabin moves, resulting in phase drifts for the transmission signal. This phase drift has a negative impact on the observation mode of very long baseline interferometry, and can be compensated by the frequency transfer system in the FAST. In this manuscript, we propose a new phase drift compensation scheme, which is denoted as data-aided channel equalization scheme. The proposed scheme is based on a hypothesis of linear phase relationship between different wavelengths in the same optical fiber, and uses the channel response information of the data-aided channel to conduct signal recovery for the astronomical signal channel. Not only the phase drift, but also the frequency-dependent distortion of the broadband transmission link can be compensated. The proposed scheme has simple transmission structure, and the function part is well modularized, so that the Astronomer users can easily turn it on or off. In the proof-of-concept experiments, the estimation deviation can be significantly reduced by estimated channel responses averaging over training sequence repetitions, showing very high accuracy of the astronomical signal channel estimation.

Soil nematode communities play a significant role in soil ecosystems. Indeed, soil nematode metabolic carbon footprint, based on nematode biomass, is used to evaluate ecosystem functioning and assess nematode response to ecosystem nutrient enrichment. However, it is unclear whether vegetation restoration affects the metabolic carbon footprint of soil nematodes and soil food webs. We selected five periods for this study including: (1) farmland (0 years), (2) grassland (30 years), (3) shrubland (60 years), (4) pioneer forest (100 years), and (5) climax forest (160 years). Community composition, diversity, and metabolic footprint of soil nematodes, and carbon flow changes through the food web were investigated. The Shannon diversity (H′) index of the soil nematode community increased in the process of restoration, and the Pielou index (J′) appeared to be lower at 30 years after vegetation restoration than at 60, 100, and 160 years. The connectance of the soil nematode food web values increased continuously, from 30 years to 160 years, reaching the highest value at 100 and 160 years, which indicated that the food web had the strongest carbon flow at 100 years after vegetation restoration on the Loess Plateau, indirectly reflecting the stability of the soil food web. Bacteria were more important than fungi in the carbon flow in the food web during vegetation restoration. The study demonstrated that vegetation restoration promoted the input of the availability of external resources, enhanced the metabolic activity of omnivorous carnivores and the soil carbon flow, and stabilized the soil food web. However, the increase in vegetation restoration time not only changed the species composition but also changed the carbon input, due to the lack of interference by agriculture. Therefore, the intrinsic mechanism needs to be studied further.

In-situ X-ray diffraction (XRD), with the sample temperature stepwise increased up to 900 °C, together with ex-situ high-resolution XRD (HRXRD), has been used to study the lattice expansion along the surface normal direction of GaN-on-Si heterostructures grown by metalorganic chemical vapor deposition (MOCVD). The thermal stabilities induced by step-graded (SG) AlxGa1−xN/AlN and multiple low-temperature (MLT) AlN buffer layers have been addressed for the heterostructures grown on 700 and 1500 µm thick Si (111) wafers, respectively. It reveals that the thermal expansion of the GaN epilayer is slightly larger than that of the Si substrate and the nitride growth tends to decrease the thermal expansion of the Si (111) wafer at lower temperatures. Onset of drop in the lattice expansions has been observed when the temperature is increased to a transition point, Ttr, and the Ttr of the MLT-AlN buffered GaN on the 1500 µm thick Si is ~500 °C, which is apparently lower than that of the SG-AlxGa1−xN/AlN buffered GaN on the 700 µm thick Si. These observations have been interpreted and attributed to convolutions among the residual lattice strains, their relaxations, and the thermal expansion coefficient mismatch induced wafer curvatures (opposite to that during MOCVD growth) at elevated temperatures.

The effect of laser treatments on the surface of stainless steel (SS420) has been studied by employing topographic mapping, X-ray fluorescence (XRF), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman backscattering spectroscopy, addressing the morphological and structural modifications. The treatments were processed in air atmosphere with varied laser-scanning speed from VL = 40 to 5 mm/s while keeping the laser power constant at 400 W. The topographic evolutions reveal an onset of surface melting when VL is reduced approaching 20 mm/s while the structural evolutions provide evidence for element redistributions and phase changes in the surface layer of the SS420 plates. The element redistributions occur not only along the transverse direction in the individual laser-scanning tracks but also along the thickness direction between the surface layer of a few nanometers thick and the near-surface layer of a few micrometers thick while the phase structures are strongly associated with the spatial redistributed elements and their oxidations. The surface melting and its VL-dependent Marangoni convections in the melt pool are believed to redistribute the elements at elevated temperatures that, in turn, give rise to the phase evolutions of the surface oxides.

This paper proposes a new method to improve the prediction accuracy of photovoltaic power generation. By improving the accuracy of photovoltaic generation prediction, the grid can reduce the restriction on photovoltaic power and thus improve the return on investment of the photovoltaic industry. This paper innovatively obtains high-quality contextual information through high-quality ontology and improves the accuracy of final prediction from the perspective of improving the quality of input data. By building a high quality context ontology model, the context is classified according to its different sources. Then the quality of the classified context is scored. Finally, the high quality context is selected to replace the low quality context. Simulation results show that this method can represent the context quality more flexibly while increasing the ontology in a small scale. Besides, this paper also used the gated recurrent neural network as the prediction model. Experimental results show that the prediction accuracy of photovoltaic power generation based on high quality context ontology and Gated Recursive Neural Network is about 5% higher than that of Long Short Term Memory model. When the number of hidden layers of the prediction network is set to 4 and the number of iterations is set to 100, the accuracy is the highest and the mean square error is 0.0037. In conclusion, this method can effectively improve the prediction accuracy and has a high application prospect in the industry.

The construction of FAST telescope was completed in Guizhou province of China in September 2016, and a kind of novel high-stability 48-core bendable and movable optical cable was developed and applied in analog data optical transmission system of FAST. Novel structure and selective material of this optical cable ensure high stability of optical power in the process of cables round-trip motion when telescope is tracking a radio source. The 10 5 times bend and stretch accelerated experiment for this optical cable was implemented, and real-time optical and RF signal power fluctuation were measured. The physical structure of optical cables after 10 5 times round-trip motion is in good condition; the real-time optical power attenuation fluctuation is smaller than 0.044 dB; the real-time RF power fluctuation is smaller than 0.12 dB. The optical cable developed in this letter meets the requirement of FAST and has been applied in FAST telescope.

Sc-substituted In2−xScx(MoO4)3 (0 ≤ x ≤ 2) ceramics were successfully synthesized by the solid state reaction method with the goal of tuning the phase transition temperature. Effects of Sc3+ substitution on the phase composition, microstructure, phase transition temperature and thermal expansion behavior of the In2−xScx(MoO4)3 (0 ≤ x ≤ 2) ceramics were investigated using XRD, FESEM, EDX, XPS and TMA, respectively. The results indicate that all samples are single phase. The relative densities of the In2−xScx(MoO4)3 ceramics increased gradually with increasing Sc3+ content. Investigations on thermal expansion properties of the In2−xScx(MoO4)3 ceramics reveal that the temperature-induced phase transition from monoclinic to orthorhombic symmetry is strongly correlated to the Sc3+ content. The obtained In2(MoO4)3 ceramics undergoes a structural phase transition from monoclinic to orthorhombic around 355.3 °C. The phase transition temperature can be significantly shifted from 355.3 °C (x = 0) to 31.9 °C (x = 1.5) by partially replacing In3+ cations with less electronegative Sc3+ cations. All In2−xScx(MoO4)3 (0 ≤ x ≤ 2) ceramics exhibit strong negative thermal expansion above the phase transition temperature. In0.5Sc1.5(MoO4)3 exhibits linear NTE over the 100–700 °C temperature range with a linear coefficient of thermal expansion of −3.99 × 10−6 °C −1.

We have synthesized InSb nanorods on InSb substrates by using metal-organic chemical vapor deposition (MOCVD). It is found that the crystal orientation of the substrate plays a remarkable role in controlling growth orientation of the InSb nanorods. On a [100]-oriented InSb substrate, the nanorods tend to lie on the substrate along its [1–10]-axis. In comparison, [111]-oriented InSb substrates tend to promote the vertical growth of InSb nanowires and free-standing InSb nanowires are consequently obtained. The evolutions of diameter and length of the nanowires on InSb (111) substrates as a function of growth temperatures, T, and input V/III source ratios, r V/III , provide the optimized growth condition, i.e., T = 400 °C and r V/III = 50. The orientated growth of one-dimensional InSb nanostructures is discussed and analized by employing a vapor-solid-solid (VSS) growth mechanism.

Plastic debris is accumulating in agricultural land due to the increased use of plastic mulches, which is causing serious environmental problems, especially for biochemical and physical properties of the soil. Dissolved organic matter (DOM) plays a central role in driving soil biogeochemistry, but little information is available on the effects of plastic residues, especially microplastic, on soil DOM. We conducted a soil-incubation experiment in a climate-controlled chamber with three levels of microplastic added to loess soil collected from the Loess Plateau in China: 0% (control, CK), 7% (M1) and 28% (M2) (w/w). We analysed the soil contents of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), NH4 +, NO3 −, dissolved organic phosphorus (DOP), and PO4 3− and the activities of fluorescein diacetate hydrolase (FDAse) and phenol oxidase. The higher level of microplastic addition significantly increased the nutrient contents of the DOM solution. The lower level of addition had no significant effect on the DOM solution during the first seven days, but the rate of DOM decomposition decreased in M1 between days 7 and 30, which increased the nutrient contents. The microplastic facilitated the accumulation of high-molecular-weight humic-like material between days 7 and 30. The DOM solutions were mainly comprised of high-molecular-weight humic-like material in CK and M1 and of high-molecular-weight humic-like material and tyrosine-like material in M2. The Microplastic stimulated the activities of both enzymes. Microplastic addition thus stimulated enzymatic activity, activated pools of organic C, N, and P, and was beneficial for the accumulation of dissolved organic C, N and P.

Giant circular blisters of up to 300 μm diameter and 10 μm deflection have been produced on nanometer-thick Al2O3-on-ZnO stacks grown by atomic layer deposition at 150 °C followed by annealing at elevated temperatures. Their shape changes upon varied ambient pressures provide evidence that their formation is related to an anneal-induced outgassing combined with their impermeability. The former mainly occurs in the bottom ZnO layer that recrystallizes and releases residual hydroxide ions at elevated temperatures while the latter is dominantly contributed by the pinhole-free Al2O3 layer on top. Vibrations at a resonant frequency of ∼740 kHz are mechanically actuated and optically probed from an individual blister. By modulating the thickness and stacking sequence of Al2O3 and ZnO, we further demonstrate a localized circular film swelling upon electron-beam irradiation and its recovery after reducing the irradiation flux. The elastic blistering and the recoverable swelling of the nanometer-thick films repres...

This paper presents a novel ultra-low-loss high-pass filter with 3 dB cutoff frequency of 890 MHz for astronomical receiver radio frequency interference mitigation application. The filter consists of three series capacitors, four shunt inductors, and microstrip circuit board. Specially, 4 shunt inductors are actualized by fabricating air-core short-circuit coaxial cable inductors in the filter box body, and the quality factor of these cable inductors is up to 762.2 and 1046, respectively, at 1.4 GHz. In the expected passband of 1.1–1.9 GHz, S parameters measurement show that insertion loss is lower than 0.16 dB and two-port return loss is larger than 20 dB; noise measurement show that filter noise temperature is lower than 8 at 300 K ambient temperature. Noise sources of this filter are analyzed by simulation and measurement.

In order to develop the Landau-Devonshire (LD) potential of the pervoskites BaTiO 3 , the Gibbs free energy of BaTiO 3 single crystal has been expanded up to 10th-order polynomial. The coefficients of the LD formulation have been phenomenologically derived based on the proposed LD model. The dependences of the spontaneous polarization, the dielectric property, and the ferroelectric hysteresis loop on temperature have been investigated systematically by using our proposed 10th-order LD model. The phenomenological thermodynamic potential near the Curie point and the three dimensional non-convex free energy landscapes corresponding to the 4th, 6th, 8th, and the 10th-order model have been analyzed numerically. Based on the proposed LD potential and coefficients, the predicted results for BaTiO 3 crystal have also been compared with experimental results as well as theoretically results reported by other researchers.

This letter presents an ultra-low loss cryogenically-coolable lumped element high pass filter and the measurement method of its S parameters and noise temperature at cryogenic temperature. This filter is going to be used in RFI mitigation of FAST wideband single pixel receiver. It adopts 5 poles Chebyshev high pass structure, and ultra-low loss lumped elements are employed. At cryogenic temperature, its 3 dB cutoff frequency is 248 MHz and the high-end of passband with ultra-low insertion loss is up to 3.5 GHz. Specially, the novel mechanical and microwave design ensure effectively cryogenic cooling to all components of the filter. This filter can be operated at temperatures of 300-4 K. S parameters are measured at room and cryogenic temperatures. At 26 K, its insertion loss in passband is smaller than 0.1 dB. A direct measurement to noise temperature at 24 K physical temperature is performed in cryogenic Testing Dewar, and noise temperature smaller than 0.55 K is achieved. The stopband rejection at 95 MHz is larger than 43 dB. In passband, the return loss of 2 ports is larger than 23 dB.

The changes in the characteristics of Panicum virgatum, an exotic invasive species, after invading various plant communities on the Loess Plateau in China and the main soil nutrient factors in these communities closely associated with invasion remain unclear. A pot culture experiment was carried out to simulate the changes in photosynthesis, biomass, and biomass allocation in P. virgatum and to identify the main soil nutrient factors in various soils collected from local plant communities. P. virgatum was grown in soils collected from communities of P. virgatum (PS treatment), Setaria viridis (SS treatment), Bothriochloa ischaemum (BS treatment), and Artemisia sacrorum (AS treatment) and in a mixed soil from the communities of S. viridis, B. ischaemum, and A. sacrorum (MS treatment). Photosynthesis in P. virgatum differed significantly among the soil treatments. Net photosynthetic rate, stomatal conductance, and photochemical efficiency (Fv/Fm) were highest in PS, whereas single-photon avalanche diode values were highest in PS and SS. The variation of biomass differed significantly in different tissues of P. virgatum in the treatments. Leaf and stem biomasses were highest in PS and SS, and root biomass was highest in PS and MS. Total biomass differed significantly among the treatments, except between BS and MS. Both the leaf to total and stem to total biomass ratios were highest in AS and SS, but the root to total biomass ratio was lowest in these two treatments. A constrained redundancy analysis and a path analysis suggested that the water-soluble nitrate-nitrogen (W-NN) concentration of the soil could significantly affect photosynthesis, biomass, and biomass allocation in P. virgatum. Photosynthesis, biomass, and biomass allocation in P. virgatum differed significantly when grown in soils from different local plant communities on the Loess Plateau. The soil W-NN concentration in these local plant communities likely has a large impact on the invasive success of P. virgatum.

ZnO/Al2O3 superlattices, i.e., nanolaminate structures, have been grown by atomic layer deposition (ALD) on Si, sapphire, and quartz substrates at 150 °C. Morphological studies show that an increase in the cycle mixing ratios of Al2O3 to ZnO tends to increase the surface smoothness via suppression of nucleation and growth of ZnO crystallites. X-ray diffraction studies reveal that the orientation of the ZnO crystallites is also affected by changing the cycle ratios of Al2O3 to ZnO under certain ALD conditions. Evolutions in the morphological, structural, and optical properties of the ZnO/Al2O3 nanolaminates upon post-growth annealing provide evidence that atomic interdiffusions occurred at elevated temperatures and the activation/diffusion of Zn atoms in the amorphous Al2O3 layers is much easier/faster than that of Al atoms in the crystallite ZnO layers. By comparing the depth profiles of Al-O, Zn, and Al-H ions measured by secondary-ion mass spectroscopy, we find that hydrogen remains in the Al2O3/ZnO nanolaminates although extensive purge durations were employed in the ALD process. The elemental hydrogen concentrations are higher at the interfaces where the ALD process switches from ZnO to Al2O3 rather than the reverses, which is strongly correlated with the etching behavior observed in an earlier publication [Chem. Mater. 15, 1020 (2003)]. Our findings shed light on further developments and ALD process of ZnO/Al2O3 superlattice structures for practical devices applications.

Integrated control systems for vehicle-handling stability are usually based on the steering bifurcation mechanism. The best integrated control performance is obtained by coordinating different control methods. However, in vehicle steering and driving conditions, the coupling characteristics of the longitudinal forces and the lateral forces of the tyres must lead to changes in the bifurcation characteristics. The corresponding vehicle dynamics stability region has to be redetermined. The corresponding integrated control method also needs to be adjusted. Therefore, in combination with the physical significance of the dynamics equilibrium point of the vehicle system, the definition of the driving stability region of the vehicle based on the characteristics of the driving torque and the steering angle bifurcation is proposed. With the concept presented above, the five-degree-of-freedom non-linear vehicle system model for the driving stability region of the vehicle was solved. The simulation results show that, according to the driving stability region of the vehicle, the vehicle dynamics stability with different driving torque inputs and different front-wheel steering-angle inputs can be accurately estimated. The study of the driving stability region of the vehicle is beneficial for engineering applications in non-linear automotive dynamics research. In addition, it provides the theoretical basis for integrated control of the vehicle-handling stability.

The sustainability of ecosystem productivity and rules governing ecosystem development are important topics of scientific research. The emergy approach is an effective method for investigating these topics, especially when used to evaluate systems that have developed under the same environmental conditions, such as climate and soil. In this paper, emergy differences between terrestrial ecosystems were studied in Guyuan County, a region representative of the agro-pastoral ecotone in Hebei Province, China. A combination of field tests and a questionnaire survey were carried out between June and August 2015. The ecosystems studied included natural grassland, artificial grassland, field crops and commercial crops. These four ecosystems were further subdivided into a total of ten ecosystems. Natural grassland was divided into free-grazing and mowed ecosystems; artificial grassland consisted of oat, Chinese leymus and corn silage; field crops included naked oats, flax and wheat; and commercial crops consisted of cabbage and potatoes. The results showed that the rain input of 4.78 × 1014 seJ/ha/yr constituted the highest renewable natural resource emergy and that the purchased emergy inputs of the ten ecosystems ranged from 3.53 to 147.67 × 1014 seJ/ha/yr. Natural resource emergy input was the basic power to maintain the ecosystem, and purchased emergy input was the direct cause of the development of the ecosystems. Groundwater was the most important non-renewable purchased energy for the production of economic crops. The emergy investment ratios (EIR) for potatoes (27.81) and cabbage (19.03) were higher than those of the other ecosystems, but mowed and artificial Chinese leymus grassland had the higher emergy self-sufficiency rates (ESR). Natural grassland, artificial Chinese leymus grassland and traditional grain crops had a low environmental load and high sustainability, whereas potatoes and cabbage had a high environmental load and low sustainability. Overall, rain-fed artificial grassland has a high development potential from the perspective of environment and productivity.

Ge and Ga-doped Ge thin films have been epitaxially grown on GaAs (001) substrates by metalorganic chemical vapor deposition (MOCVD). Structural studies revealed that the temperature of the substrate played an important role in controlling the Ga-incorporations as well as affecting the surface morphologies. Dot, dot-in-hole, and hole structures have been observed by changing the growth temperatures under, otherwise, the same MOCVD conditions for p-type Ge. These surface features are associated with segregation, migration, and coalescence of Ga-rich droplets on the growing surface, especially when Ga-doping is introduced. Mode softening of the longitudinal optical (LO) phonon of Ge has also been observed. This mode softening is dominated by the effect of free-carrier concentrations more than the effect of doping-induced crystal disordering and lattice strain. We have also observed atomic interdiffusions across the Ge/GaAs interface by employing spatially resolved Raman scattering and high-resolution X-ray diffraction (HRXRD), measuring from the cross-section of the Ge/GaAs heterostructure. Such atoms intermixing cause great challenges in controlling the doping concentrations in the Ge epilayer, they could also give rise to an intermediate layer in between the Ge epilayer and the GaAs substrate. Detailed morphological and structural properties of these Ge-on-GaAs heterostructures have been discussed in this paper, which could have important consequence when optimizing the Ge-on-GaAs growth by MOCVD.

The Zhaxikang Pb-Zn-Sb deposit is one of the most important deposits in the Southern Tibet metallogenic belt. Based on field geology, petrography, melt- and fluid inclusions and C-H-O isotopes, we describe and discuss the mineralization, alteration, and their possible link with magmatic fluids. Our results show that the Zhaxikang deposit shares many geological and geochemical similarities with typical intermediate-sulfidation (IS) epithermal deposits. The Pb-Zn-Sb mineralization is closely related to Fe-Mn carbonate- and silicic alterations, which formed the outer rim around the greisen in the Cuonadong Dome. Orebodies occur mainly as structurally-controlled veins and breccia dikes, with major minerals include sphalerite, galena, pyrite, arsenopyrite, and Fe-Mn carbonates. Main stage ore-forming fluids were of medium temperature (214–292 °C), low salinity (2.6–5.3 wt.% NaCl eqv.) and CO 2 -bearing. Melt/fluid inclusions in beryl and quartz from the pegmatite indicate that the primary magmatic fluids were derived from the melt-fluid immiscibility. The magmatic fluids were of low salinity (0.2–7.9 wt.% NaCl eqv.), high temperature (298–457 °C) and CO 2 -rich, and contained minor CH 4 , N 2 , C 2 H 6 , C 3 H 8 and C 6 H 6 . The presence of Mn-Fe carbonates and daughter gahnite minerals in the beryl-hosted inclusions indicates high Mn, Fe and Zn contents in the parental magma and related magmatic fluids. This implies a genetic link between magmatic fluids and the Pb-Zn-Sb mineralization, as also supported by Ar-Ar dating and H-O-C isotopic evidence. We suggest that the Zhaxikang is best classified as an IS epithermal deposit, and the ore-forming fluids are likely to be magma-derived. Boiling of the magmatic fluids led to high-salinity fluids and metal enrichment. High regional geothermal gradient caused by the thermal doming event may have facilitated long distance transportation of magmatic fluids, and led to the formation of a wide alteration zone and distal Pb-Zn-Sb mineralization. The temperature drop and meteoric water involvement may have precipitated the Pb-Zn-Sn minerals in the distal fault systems.

Alcohol sensing devices provide safety precautions against exposure to toxic gases in both indoor and outdoor environments. In this study, for comparison between TiO2 and BaTiO3 materials, alcohol-sensing tests determine the better material. The two materials that makes up the seed layers have excellent dielectric constants while Titania nano-rods grown on these seed layers will affect the prototype’s sensitivity during ethanol drop testing. The hydrothermal process synthesized the TiO2 nano-rods on Titania seed layer and Barium Titanate seed layer coated on silicon wafers. The Magnetron Sputtering deposited seed layers of different thickness with various parameters. The plasma fine coating deposits platinum to function as contact points of the device. Varying hydrothermal growth duration achieved nano-rods of different length and diameter. The dimensions and of the nano-rods are determined with Scanning Electrons Microscope (SEM). Alcohol sensing tests at room temperature (25oC) using different concentrations of ethanol were done and has shown that samples with nano-rods has better sensitivity compared to sample without nano-rods. Optimal results from the sample with TiO2 seed layer are gathered. The samples with nano-rods have improved sensitivity compared to samples without nano-rods. This can be due to larger surface area contact with ethanol. TiO2 sample with nano-rods shows an increasing trend of recovery time as the ethanol concentration increases while BaTiO3 sample with nano-rods shows a more consistent recovery time despite the increase in ethanol concentration.

We present the growth of InSb nanowires (NWs) by using metal-organic chemical vapor deposition (MOCVD). During the process, an indium rich layer was created by introducing TMIn source before initializing the InSb NW growth. The effects of growth parameters such as temperature and V/III ratio on the product have been well studied. The growth of InSb NWs occurs within a small temperature range. This study also indicated that the nanowire quality was also affected at very high or very low input V/III ratio. A self-nucleation growth based on indium droplets was proposed to be the growth mechanism of the InSb NWs obtained here, which is unlike the conventional tip-led VLS or VSS growth in the catalyst-assisted processes.

Y 2 W 3 O 12 thin films have been grown on quartz substrates by pulsed laser deposition (PLD). The effects of oxygen pressure, substrate temperature and annealing temperature on the phase compositions and morphologies of the Y 2 W 3 O 12 thin films were investigated using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The negative thermal expansion coefficients of the Y 2 W 3 O 12 ceramic target and thin film were investigated using high temperature X-ray diffraction (HTXRD) and thermal mechanical analyzer (TMA). The results indicate all the as-deposited Y 2 W 3 O 12 thin films to show amorphous regardless of oxygen pressures from 5 Pa to 20 Pa and substrate temperatures from room temperature to 500 °C. Y 2 W 3 O 12 thin film grown at 500 °C with an oxygen pressure of 10 Pa displays the smoothest and most uniform surface morphology. Crystallized orthorhombic Y 2 W 3 O 12 thin films were prepared by heating at 1000 °C for 7 min in air. The crystallized Y 2 W 3 O 12 thin film is polycrystalline and shows a compact surface morphology. The mean grain size of Y 2 W 3 O 12 thin film is about 0.2–1 µm. Orthorhombic Y 2 W 3 O 12 thin film exhibits an anisotropic negative thermal expansion. The thermal expansion coefficients of a -axis, b -axis c -axis and cell volumes are caculated to be −12.33×10 −6 K −1 , −4.99×10 −6 K −1 , −11.01×10 −6 K −1 and −28.22×10 −6 K −1 in the temperature range from 100 to 600 °C, respectively. The average linear thermal expansion coefficient of the Y 2 W 3 O 12 thin film is calculated to be −9.41×10 −6 K −1 .

Background: Airway epithelium plays an essential role in maintaining the homeostasis and function of respiratory system as the first line of host defense. Of note, epithelial sodium channel (ENaC) is one of the victims of LPS-induced airway injury. Regarding the great promise held by mesenchymal stem cells (MSCs) for regenerative medicine in the field of airway injury and the limitations of cell-based MSCs therapy, we focused on the therapeutic effect of MSCs conditioned medium (MSCs-CM) on the ENaC activity in mouse tracheal epithelial cells. Methods: Ussing chamber apparatus was applied to record the short-circuit currents in primary cultured mouse tracheal epithelial cells, which reflects the ENaC activity. Expressions of α and γ ENaC were measured at the protein and mRNA levels by western blot and real-time PCR, respectively. The expression of with-no-lysinekinase- 4 (WNK4) and ERK1/2 were measured at protein levels, and the relationship between WNK4 and ERK1/2 was determined by WNK4 knockdown. Results: MSCs-CM restored the LPS-impaired ENaC activity, as well as enhanced the mRNA and protein expressions of ENaC in primary cultured mouse tracheal epithelial cells. Meanwhile, WNK4 and ERK1/2, both negative-regulators of ENaC, were suppressed accordingly after the administration of MSCs-CM in LPS-induced airway injury. After WNK4 gene was knocked down by siRNA, the level of ERK1/2 phosphorylation decreased. Conclusion: In light of the key role of ENaC in fluid reabsorption and the beneficial effects of MSCs-CM in the injury of airway epithelium, our results suggest that MSCs-CM is effective in alleviating LPS-induced ENaC dysfunction through WNK4-ERK1/2 pathway, which will provide a potent direction for the therapy of airway injury.

Background The major landscape in the hilly-gully region of the Loess Plateau is greatly affected by vegetation rehabilitation on abandoned cropland. Although many studies have shown that the rehabilitation have greatly improved soil conditions and protected them from erosion, these effectiveness were not always in consensus possibly due to the land type of vegetation or to the rehabilitation time. To close this gap, we conducted a long term experiment as follows. Methods In this study, we analysed four land types of vegetation rehabilitation (shrub land, woodland, naturally revegetated grassland, and orchard land) with different rehabilitation times and investigated the mechanical composition and erodibility of the soil. Areas of slope croplandand natural forest were selected as controls. Results The results showed that soil depth, rehabilitation time and rehabilitation land type had strong impacts on soil mechanical composition, micro-aggregation and erodibility. Following rehabilitation, naturally revegetated grassland and shrub land had lower fractal dimensions of particle size distribution (fractal dimensions of PSD), fractal dimensions of micro-aggregation, and erodibility (K factor) than did cropland. Compared to the positive effects of rehabilitation mainly happened in the topsoil layer at other rehabilitation land type, that of woodland happened in the deeper soil layer. Besides, the indispensable rehabilitation time for the significant improvement of soil condition was shorter at naturally revegetated grassland than that at shrub land and woodland. Discussion Although rehabilitation time was more influential than was rehabilitation land type or soil depth, the differences among the rehabilitation land types showed that naturally revegetated grassland with native plants is the most time-saving rehabilitation vegetation for the Loess Plateau in the conversion from slope cropland. The success of rehabilitation in this forestry practice was mainly contributed by the suited species of rehabilitation land type to the local climate and soil. Based on the differences of rehabilitation effectiveness resulting from land type, we should be cautious to choose land types for the rehabilitation of soil conditions in the Loess Plateau.

Slope aspect is an important topographic factor for a micro-ecosystem environment that may affect macro- and micronutrients in plants and soil. The south-, northwest-, and north-facing slopes were selected to investigate the influence of slope aspect on the concentrations, storage, and allocation of macro- and micronutrients in Artemisia sacrorum on the Loess Plateau in China. The concentrations of available manganese (Mn) in both rhizosphere and non-rhizosphere soils reached their maximum on the north-facing slope. The concentrations of available iron (Fe) in rhizosphere soil and available copper (Cu) in non-rhizosphere soil reached their maximum on the south-facing slope. Slope aspect significantly affected the total concentrations of potassium (K), calcium (Ca), magnesium (Mg), Cu, and Mn in rhizosphere and non-rhizosphere soils, and all of these elements reached their maximum on the northwest-facing slope. Slope aspect significantly influenced the concentrations of aboveground K, Ca, and Mg, sodium (Na), Mn, and belowground K in A. sacrorum, and the concentrations of aboveground K, Ca, Mg, and Na and belowground Mn, Na, Fe, Ca, and Mg in weed. Most elements in A. sacrorum and the weeds reached their maximum on the south-facing slope. Slope aspect significantly changed the aboveground-to-belowground concentration ratios of K, Ca, and Na in A. sacrorum and weed. Slope aspect significantly affected the storage of macro- and micronutrients in A. sacrorum and weed but not the storage in the plants of the entire plot. Slope aspect predominantly affected the storage allocation of macro- and micronutrients in A. sacrorum but not those in weed. Slope aspect is an important topographic factor that affects the macro- and micronutrients in plants and soil in micro-ecosystem environments.

To enhance efficiency, convenience, and safety of Parkinson's disease (PD) treatment for geriatric patients, an advanced suspension of Levodopa/Benserazide hydrochloride (LD/BH) has been prepared by cation-exchange resin and used to synchronize sustained release of LD and BH by optimizing coating parameters and prescription. For the purpose, LD and BH were immobilized on the surface of cation-exchange resin, respectively. Based on HPLC results, the cation-exchange resin showed high loading capacity. The studies on drug loading mechanism indicated that both drugs were immobilized by electrostatic interaction rather than physical adsorption. After PEG modification, pretreated drug-resin complexes were coated by emulsion-solvent evaporation method. In order to control drug release in a sustained manner, coating parameters of drug-resin microcapsules were optimized respectively by single-factor analysis. Further, coating prescription of the microcapsules was optimized to synchronize sustained release of LD and BH in vitro by orthogonal design. Utilizing optimal LD-resin microcapsules and BH-resin microcapsules, LD/BH suspension, containing both of them, was prepared by an optimal formulation and characterized by accelerated test and pharmacokinetic study in vivo. The accelerated test confirmed high stability of LD/BH suspension. According to pharmacokinetic results in vivo, in contrast with LD/BH commercial tablets, LD/BH suspensions did not only synchronize sustained release of both drugs but also show good bioequivalence. As LD/BH sustained release suspension can synchronize sustained release of multiple active ingredients by oral administration, the suspension presents promising oral dosage forms for geriatric patients with PD. An advanced Levodopa/Benserazide hydrochloride (LD/BH) suspension, prepared by cation-exchange resin and optimized microencapsulation, synchronizes sustained releases of LD and BH in vivo to benefit Parkinson's disease treatment for geriatric patients.

The molecular interactions between compound and polymeric carriers are expected to highly contribute to high drug load and good physical stability of solid dispersions. In this study, a series of amorphous solid dispersions (ASD) of Curcumin (Cur) were prepared with different polymers by the solvent evaporation method. With the carrier polyvinylpyrrolidone (PVP), the amorphous solid dispersion system exhibits a better solubility and stability than that with poloxamers and HP-&beta, CD due to the strong drug-polymer interaction. The drug/polymer interaction and their binding sites were investigated by combined experimental (XRD, DSC, FTIR, SEM, Raman, and 1H-NMR) and molecular dynamics simulation techniques. The Curcumin ASD demonstrated enhanced bioavailability by 11-fold and improved anti-inflammatory activities by the decrease in cytokine production (MMP-9, IL-1&beta, IL-6, VEGF, MIP-2, and TNF-&alpha, ) compared to the raw Curcumin. The integration of experimental and modeling techniques is a powerful tool for the rational design of formulation development.

Photodetectors, which are capable of detecting light with varied wavelength, have nowadays been widely applied onto emerging fields such as security, entertainment, healthcare, environment, and so on. As the one with a two-dimensional layered structure, molybdenum disulfide (MoS

A Mo-Ni alloy has been demonstrated to be a benchmark noble-metal-free catalyst for the hydrogen evolution reaction (HER) in alkaline solutions. Nevertheless, further improvement on its catalytic activity is desired to meet industrial requirements. In this study, Mo-Ni-based hollow structures (MoNi-HS), backboned by MoO

A GH49 dextranase gene DexKQ was cloned from marine bacteria Arthrobacter oxydans KQ11. It was recombinantly expressed using an Escherichia coli system. Recombinant DexKQ dextranase of 66 kDa exhibited the highest catalytic activity at pH 9.0 and 55 °C. kcat/Km of recombinant DexKQ at the optimum condition reached 3.03 s−1 μM−1, which was six times that of commercial dextranase (0.5 s−1 μM−1). DexKQ possessed a Km value of 67.99 µM against dextran T70 substrate with 70 kDa molecular weight. Thin-layer chromatography (TLC) analysis showed that main hydrolysis end products were isomalto-oligosaccharide (IMO) including isomaltotetraose, isomaltopantose, and isomaltohexaose. When compared with glucose, IMO could significantly improve growth of Bifidobacterium longum and Lactobacillus rhamnosus and inhibit growth of Escherichia coli and Staphylococcus aureus. This is the first report of dextranase from marine bacteria concerning recombinant expression and application in isomalto-oligosaccharide preparation.

The antihypertensive drug felodipine (FD) is a typical biopharmaceutics classification system (BCS) II drug; thus, improving the dissolution rate of FD is very important to enhance its bioavailability. Besides, according to the in situ “close loop” perfusion assay, we found that the jejunum is the main absorptive site, then the duodenum and ileum. Consequently, a novel micron-size particulate of FD in a core-shell structure was fabricated by a coaxial electrospray technique; within the drug delivery system, Hypromellose K4M (HPMC K4M) was selected as a sheath material to prolong the retention time in the upper GI tract, while povidone K30 (PVP K30) was mixed with FD in the inner layer. The dissolution study in three different media (0.02% Tween-80 solution; phosphate buffer containing 0.02% Tween-80, pH 6.8; and HCl solution containing 0.02% Tween-80, pH 1.2) demonstrated that FD-loaded coaxial electrospray particles (F-COES) could greatly improve the dissolution of FD. Furthermore, in vivo pharmacokinetics revealed that F-COES emerged no changes in the half-life but significantly prolonged the tmax and increased the oral bioavailability. Collectively, this work supplies a promising drug release system that will improve the dissolution and enhance the bioavailability simultaneously for those poorly water-soluble drugs mainly absorbed in the upper GI tract.

To assist with the commissioning (Jiang et al. 2019) of the Five-hundred-meter Aperture Spherical radio Telescope (FAST), we performed a pulsar search, with the primary goal of developing and testing the pulsar data acquisition and processing pipelines. We tested and used three pipelines, two (P1 and P2 hereafter) searched for the periodic signature of pulsars whereas the other one was used to search for bright single pulses (P3 hereafter). A pulsar candidate was discovered in the observation on the 22nd August, 2017, and later confirmed by the Parkes radio telescope on the 10th September, 2017. This pulsar, named PSR J1900-0134, was the first pulsar discovered by FAST. The pulsar has a pulse period of 1.8 s and a dispersion measure (DM) of 188\,pc\,cm$^{-3}$., Comment: Sci. China-Phys. Mech. Astron. 62, 959508 (2019)

The Five-hundred-meter Aperture Spherical radio Telescope (FAST) was completed with its main structure installed on September 25, 2016, after which it entered the commissioning phase. This paper aims to introduce the commissioning progress of the FAST over the past two years. To improve its operational reliability and ensure effective observation time, FAST has been equipped with a real-time information system for the active reflector system and hierarchical commissioning scheme for the feed support system, which ultimately achieves safe operation of the two systems. For meeting the high-performance indices, a high-precision measurement system was set up based on the effective control methods that were implemented for the active reflector system and feed support system. Since the commissioning of the FAST, a low-frequency ultra-wideband receiver and 19-beam 1.05-1.45 GHz receiver have been mainly used. Telescope efficiency, pointing accuracy, and system noise temperature were completely tested and ultimately achieved the acceptance indices of the telescope. The FAST has been in the process of national acceptance preparations and has begun to search for pulsars. In the future, it will still strive to improve its capabilities and expand its application prospects., Sci. China-Phys. Mech. Astron. 62, 959502 (2019)

Using density functional theory calculations, we investigated the structure and electronic properties of cyclooctatetraene (C8H8, COT)-ligand mono- or bi-transition-metal (M) sandwich clusters, Mn(COT)n+1 (M = Sc, Ti, Cr, Mn, n = 1, 2) or (COT)M1(COT)M2(COT), as well as their one-dimensional infinite molecular wires. All the sandwich M–COT clusters and molecular wires are rather stable with their binding energies ranging from 3.20 to 7.48 eV per transition-metal atom. Superior to MnBzn+1 complexes, most sandwich M–COT complexes are in their high spin states with ultrahigh magnetic moments. Moreover, one-dimensional infinite molecular wires, [Cr(COT)]∞, [(COT)V(COT)Ti]∞ and [(COT)Sc(COT)Cr]∞, are predicted to be ferromagnetic half-metals. Our findings suggest that such M–COT sandwich complexes may be potential candidates for applications in spintronics.

A sensitive and accurate LC-MS/MS method was established for quantifying salvianolic acid B (Sal B), rosmarinic acid (Ros A) and Danshensu (DA) in rat plasma. Salvia miltiorrhiza polyphenolic acid (SMPA), active water-soluble ingredients isolated and purified from Salvia miltiorrhiza Bge included Sal B, Ros A and DA. The pharmacokinetic analysis of Sal B, Ros A and DA after pulmonary administration of SMPA solution to rat was performed by LC-MS/MS. Results from the pharmacokinetic studies showed that the peak concentration of DA was 21.85 ± 6.43 and 65.39 ± 3.83 ng/mL after pulmonary and intravenous administration, respectively. DA was not detected at 2 h after administration. The absolute bioavailabilities of Sal B and Ros A were respectively 50.37 ± 27.04 and 89.63 ± 12.16% after pulmonary administration of 10 mg/kg SMPA solution in rats. The absolute bioavailability of Sal B increased at least 10-fold after pulmonary administration, compared with oral administration. It was concluded that the newly established LC-MS/MS method was suitable for describing the pharmacokinetic characteristics of Sal B, Ros A and DA in rat after pulmonary administration of SMPA solution. The data from this study will provide a preclinical insight into the feasibility of pulmonary administration of SMPA.

Influenza virus has a significant impact on the respiratory system. The mechanism of how influenza virus impairs the fluid transport in airway is not fully understood. We examined its effects on epithelial sodium channels (ENaC), which are very important for water and salt transport in the respiratory system. We focused on the impacts of influenza virus on ENaC activity in mouse tracheal epithelial cells (MTECs) and applied Ussing chamber apparatus for recording the short-circuit currents in primary cultured MTECs. Expressions of α and γ-ENaC were measured at the protein and mRNA levels by western blot and quantitative real-time polymerase chain reaction, respectively. Roles of the with-no-lysine-kinase-4 (WNK4) pathway were considered in participating influenza virus-involved ENaC regulation by using siRNA to knockdown WNK4 and the physical properties of airway surface liquid (ASL) were detected by confocal microscopy. Our results showed that influenza virus reduced ENaC activity, and the expressions of α and γ-ENaC were decreased at the protein and mRNA levels, respectively. WNK4 expression increased time-dependently at the protein level after influenza virus infection, while knockdown of WNK4 rescued the impact of influenza virus on ENaC and ASL height increased obviously after MTECs were treated with influenza virus. Taken together, these results suggest that influenza virus causes the changes of biophysical profile in the airway by altering the ENaC activity at least partly via facilitating the expression of WNK4.

It is necessary to analyze in detail, diagnose accurately, and design practical surgical options before extraction surgery; to make sure that each operation step and action should be stable, gentle, and accurate in order to avoid and reduce unnecessary tissue damage during surgery; and to minimize the reaction and reduce the incidence of complications as much as possible after operation.

We describe PSR J1926-0652, a pulsar recently discovered with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Using sensitive single-pulse detections from FAST and long-term timing observations from the Parkes 64-m radio telescope, we probed phenomena on both long and short time scales. The FAST observations covered a wide frequency range from 270 to 800 MHz, enabling individual pulses to be studied in detail. The pulsar exhibits at least four profile components, short-term nulling lasting from 4 to 450 pulses, complex subpulse drifting behaviours and intermittency on scales of tens of minutes. While the average band spacing P3 is relatively constant across different bursts and components, significant variations in the separation of adjacent bands are seen, especially near the beginning and end of a burst. Band shapes and slopes are quite variable, especially for the trailing components and for the shorter bursts. We show that for each burst the last detectable pulse prior to emission ceasing has different properties compared to other pulses. These complexities pose challenges for the classic carousel-type models., Comment: 13pages with 12 figures

Wisdom teeth are obstructed by the surrounding tissues and stay in the jaw during the process of growth and eruption. In order to extract wisdom teeth or to make them easily dislocated, we must first know the resistance surrounding wisdom teeth. In addition, we also need to know, for instance, the size of the crown, the length and the degree of bending of the roots, as well as the relationship with the surrounding soft and hard tissues.