Piece Of Film Research Articles

Highly Sensitive DNA Sensing in Subthreshold Regime with ITO-Based One-Piece Thin Film Transistor

INTRODUCTION Solution-gated field-effect transistors (FETs) with silicon or other semiconductive materials as channels can specifically and selectively detect ions and biomolecules in biological samples by chemically modifying the gate electrode surface, and these are known as biologically coupled FETs (Bio-FETs) [1]. Since Bio-FETs can directly detect the charges of ions and biomolecules, they do not require to label fluorescent dyes and to induce redox reactions based on enzymes. Therefore, Bio-FETs are expected to be used as in vitro diagnostic devices for a label-free monitoring of health conditions in daily life.Our research group is investigating the application of thin-film transistors (TFTs) composed of indium tin oxide (ITO), which has been widely used as an electrode material for displays owing to its transparency and conductivity, to Bio-FETs. Considering the fact that the ITO thin film is not only conductive but also semiconductive, depending on the thickness, we have found that solution-gated FETs can be fabricated by one-step sputtering of ITO [2]. Moreover, by etching a part of the conductive ITO film with the thickness of 100 nm) to the optimal thickness (< 30 nm), which induces semiconductive characteristics, a solution-gated ITO-TFT can be fabricated, which is composed of one piece of ITO thin film and whose shape and properties can be precisely controlled [3]. The ITO-based one-piece TFT has no interface among the source/channel/drain electrodes and exhibits a steep subthreshold slope (SS) of about 80 mV/decade, which is based on the large capacitance of the electric double layer formed by the direct contact of electrolyte solutions with the ITO channel surface,. Therefore, the ITO-based one-piece TFT is expected to be applied to biosensors with high sensitivity.In this study, we demonstrate the possibility of a highly sensitive DNA detection in the steep SS with the ITO-based one-piece TFT for the biosensing application. In particular, DNA probes are chemically modified on the ITO channel surface, and then DNA hybridization is detected in the near subthreshold regime with the ITO-based one-piece TFT.EXPERIMENTAL First, photoresist was patterned on a glass substrate by photolithography. ITO thin film (100 nm thickness) was deposited on the patterned area by sputtering, and photoresist was removed using a solvent. Next, as shown in Figure 1, photolithography was used again to deposit the resist film so that the channel portion was exposed. Subsequently, a drop of 0.1 M hydrochloric acid was dropped onto the exposed channel area, and then the exposed area was etched. Etching was controlled by monitoring the conductivity between the source and drain over time. Moreover, thiolated DNA probes were immobilized on the channel surfaces of the fabricated devices using m-maleimidobenzonyl-N-hydroxysuccinimide ester (MBS) as a crosslinker to the amino groups at the poly-serotonin surface as the anchor layer (Figure 1). Thus, DNA probes were fixed on the surface to detect the target DNA, and various bioaffinity parameters such as detection limit and sensitivity were investigated in the near-subthreshold region of ITO-based one-piece TFTs.A semiconductor parameter analyzer was used to monitor conductivity during etching and to evaluate electrical properties such as gate voltage (VG)-drain current (ID) transfer characteristics of the fabricated ITO-based one-piece TFTs. AFM (Bruker) was used to evaluate the shape of the surface chemical modification.RESULTS and DISCUSSION The ITO-based one-piece TFT functionalized with DNA probes was used to evaluate the potential response to the addition of target DNA. The measurement was conducted in the near-subthreshold regime. As a result, the DNA probe-modified device showed the larger electrical signals than the device without the modification of DNA probes. This suggests that the functionalized ITO-based one-piece TFT enables the highly sensitive detection of biomolecules in the subthreshold regime.CONCLUSIONS In this study, we demonstrated the relatively highly sensitive DNA detection even in the near subthreshold regime with the ITO-based one-piece TFT with DNA probes. This indicates that the functionalized ITO-based one-piece TFT would allow the specific detection of various biomarkers in the subthreshold regime, which has the potential to be applied to biosensors with high sensitivity in the future.REFERENCES[1] Sakata, T. ACS Omega 2019, 4, 11852.[2] Sakata, T.; Nishitani, S.; Saito, A.; Fukasawa, Y. ACS Appl. Mater. Interfaces 2021, 13, 38569.[3] Katayama, R.; Sakata, T. ECS Trans. 2023, 111, 37. Figure 1

Energy dependence of GafChromic LD-V1 film dose response to X-ray photons in the 60 to 180 kV range

Abstract Introduction: Radiochromic film (RCF) is suitable for use as a dosimeter owing to its inherently superior spatial resolution and near-water equivalence. A new model of RCF recommended for measuring imaging dose in the kV nominal energy range was recently introduced onto the market. In this study, we investigate the dependence on the beam quality of GafChromic LD-V1 film’s radiation dose response. Material and methods: Pieces of LD-V1 film were irradiated to air kerma ranging from 0 to 570 mGy in X-ray photons with beam qualities of 60 kV (HVL = 1.32 mm Al), 100 kV (HVL = 2.83 mm Al), 120 kV (HVL = 5.11 mm Al), 150 kV (HVL = 6.23 mm Al), and 180 kV (HVL = 0.54 mm Cu). The net reflectance from each film was obtained from a color flatbed scanner. For each beam quality, an analytical power function was fitted to the net reflectance - air kerma relationship and tested for differences. Results: We have found that for the beam qualities investigated, the response of the Gafchromic LD-V1 film was not significantly dependent on energy, and a single calibration curve could be used. The total relative uncertainty and absolute error reached maxima of 18% and 80%, respectively for air kerma values less than 50 mGy, and remained below 10% for air kerma in the range 50 mGy to 570 mGy. Conclusions: The results of our investigation revealed that the response of Gafchromic LD-V1 film is not significantly dependent on beam quality. A minimum air kerma irradiation of 50 mGy is recommended to minimise uncertainty.

Investigation of dosimetric characteristics of radiochromic film in response to alpha particles emitted from Americium-241.

In radiotherapy, it is essential to deliver prescribed doses to tumors while minimizing damage to surrounding healthy tissue. Accurate measurements of absorbed dose are required for this purpose. Gafchromic® external beam therapy (EBT) radiochromic films have been widely used in radiotherapy. While the dosimetric characteristics of the EBT3 model film have been extensively studied for photon and charged particle beams (protons, electrons, and carbon ions), little research has been done on -particle dosimetry. -emitting radionuclides have gained popularity in cancer treatment due to their high linear energy transfer, short range in tissue, and ability to spare surrounding organs at risk, thereby delivering a more localized dose distribution to the tumor. Therefore, a dose-calibration film protocol for -particles isrequired. This study aimed to develop a dose-calibration protocol for the -particle emitting radionuclide 241Am, using Monte Carlo (MC) simulations and measurements with unlaminated EBT3films. In this study, a MC-based user code was developed using the Geant4 simulation toolkit to model and simulate an 241Am source and an unlaminated EBT3 film. Two simulations were performed: one with voxelized geometries of the EBT3 active volume composition and the other using water. The dose rate was calculated within a region of interest in the voxelized geometries. Unlaminated EBT3 film pieces were irradiated with the 241Am source at various exposure times inside a black box. Film irradiations were compared to a 6-MV photon beam from a Varian TrueBeam machine. The simulated dose rate was used to convert the exposure times into absorbed doses to water, describing a radiochromic-film-based reference dosimetry protocol for -particles. The irradiated films were scanned and through an in-house Python script, the normalized pixel values from the green-color channel of scanned film images wereanalyzed. The 241Am energy spectra obtained from the simulations were in good agreement with IAEA and NIST databases, having differences 0.516% for the emitted -rays and produced characteristic x-rays and 0.006% for the -particles. Due to the short range of -particles, there was no energy deposition in the voxels outside the active 241Am source region projected onto the film surface. Thus, the total dose rate within the voxels covering the source was 0.847 0.003 Gy/min within the sensitive layer of the film (LiPCDA) and 0.847 0.004 Gy/min in water, indicating that the active volume can be considered water equivalent for the 241Am beam quality. A novel approach was employed in -film dosimetry using an exponential fit for the green channel, which showed promising results by reducing the uncertainty in dose estimation within 5%. Although the statistical analysis did not reveal significant differences between the 6-MV photon beam and the calibration curves, the dose-response curves exhibited the expected behavior. The developed MC user code simulated the experimental setup for -dosimetry using radiochromic film with acceptable uncertainty. Unlaminated EBT3 film is suitable for the dosimetry of -radiation at low doses and can be used in conjunction with other unlaminated GafChromic® films for quality assurance and researchpurposes.

Gafchromic EBT3 film provides equivalent dosimetric performance to EBT-XD film for stereotactic radiosurgery dosimetry

The accurate assessment of film results is highly dependent on the methodology and techniques used to process film. This study aims to compare the performance of EBT3 and EBT-XD film for SRS dosimetry using two different film processing methods. Experiments were performed in a solid water slab and an anthropomorphic head phantom. For each experiment, the net optical density of the film was calculated using two different methods; taking the background (initial) optical density from 1) an unirradiated film from the same film lot as the irradiated film (stock to stock (S-S) method), and 2) a scan of the same piece of film taken prior to irradiation (film to film (F-F) method). EBT3 and EBT-XD performed similarly across the suite of experiments when using the green channel only or with triple channel RGB dosimetry. The dosimetric performance of EBT-XD was improved across all colour channels by using an F-F method, particularly for the blue channel. In contrast, EBT3 performed similarly well regardless of the net optical density method used. Across 21 SRS treatment plans, the average per-pixel agreement between EBT3 and EBT-XD films, normalised to the 20 Gy prescription dose, was within 2% and 4% for the non-target (2—10 Gy) and target (> 10 Gy) regions, respectively, when using the F-F method. At doses relevant to SRS, EBT3 provides comparable dosimetric performance to EBT-XD. In addition, an S-S dosimetry method is suitable for EBT3 while an F-F method should be adopted if using EBT-XD.

A non-beam-based Doppler broadening of positron annihilation radiation (DBAR) spectrometer for a single piece of micron-thickness film

Doppler broadening of positron annihilation radiation (DBAR) spectroscopy is a critical technique to provide electronic momentum information of materials. For conventional non-beam-based DBAR experiments, due to the continuous distribution of initial kinetic energy (0-545 keV) of positrons from 22Na source, two pieces of identical samples with sufficient thickness (> 1 mm for each sample with a density of 1 g/cm3) are required to stop almost all positrons in the samples. However, in many film studies, it is difficult or even impossible to meet this sample thickness requirement. In this work, judging by the output signals of a specially designed anticoincidence detector, the annihilation of positrons in a film sample and positron source are selectively collected. Furthermore, a new method is proposed to correct high-proportioned source components. Based on this, for the first time, a non-beam-based DBAR spectrometer was developed for a single piece of micron-thickness film. This approach will drastically broaden the application of DBAR spectroscopy in film characterization in future.

Prestressing method to inhibit crack initiation and expansion in a large-sized diamond film during polishing

A piece of diamond film (Ø 125 mm) was polished based on prefabricated stress. The diamond film was glued to a metal workpiece at high temperatures. The difference in the thermal expansion coefficients between the diamond film and the workpiece was exploited to prefabricate stress in the middle of the two materials. This prefabricated stress had a compressive effect on the diamond film, offset the stress generated in the grinding and polishing process, and prevented the diamond film from cracking. The feasibility of the prestressing method was verified by a combination of experiments and finite element simulations. The prestressing method was used to bond the diamond film to a 10 mm-thick brass fixture at 20, 50, 70, and 90 °C. It was found that when the temperature of the bonded diamond film reached 90 °C, the increase in the prefabricated stress was −410.71 MPa. The finite element simulation results were found to be consistent with the experimental data. The diamond film was cooled down to room temperature after bonding at high temperatures to simulate the prefabricated stress generation process. The diamond film with the prefabricated stress was again heated to the bonding temperature to simulate the stress change caused by the frictional heat generated during the polishing process. The stress of the bonded sample increased when it was cooled down to room temperature. The stress on the diamond surface became smaller during the polishing process, and the stress almost disappeared with the rise in bonding temperature, verifying the viability of the prestressing method.

Direct, model-free acoustic evaluation of stresses and strains in loaded nonlinear soft solids

We show analytically and experimentally that the states of stress and strain existing in a mechanically loaded elastic material can be accessed directly from elastic wave speed measurements, without having to determine, or even know, its material linear and nonlinear elastic parameters. These techniques are expected to have important applications in the health monitoring of loaded structures. Examples include stressed hydrogels, muscles, and thin membranes, such as a stretched rubber sheet, a piece of cling film (∼10 μm thick), and the animal skin of a bodhrán, a traditional Irish drum.

Creating a new yellow and blue combination transparent film for Panax ginseng C.A. Meyer growth based on orthogonal designs

Panax ginseng C.A. Meyer originates from old-growth forest environments, where the light intensity and spectrum reaching the forest bed are influenced by the canopy and humidity. In farmlands, suitable light intensity for cultivation is achieved by controlling the light transmission rate using shading nets, while light quality is regulated by a cover of yellow or blue transparent film. Such films have a light quality distinct from that produced by old-growth forests. Herein, a large composite film was developed by alternating small pieces of yellow and blue transparent film. An orthogonal array was used to evaluate the influence of the small transparent film area (STFA), yellow transparent film (YTF) number, and blue transparent film (BTF) number on the associated changes in ginseng in a range of fluorescence-, photosynthesis-, morphology-, and crop quality-related factors. Our results showed that light intensity was influenced primarily by STFA, which caused an overall decrease, while the light quality ratio was affected primarily by YTF number, which increased the proportion of red light and decreased that of blue light, with corresponding influence on different growth parameters. Based on these observations, an improved yellow and blue combination transparent film (YBCTF) with the following characteristics was established: STFA: 15 × 15 cm, YTF: two pieces, and BTF: three pieces. The improved YBCTF facilitated efficient light energy use by the plants, and led to an increase in leaf area, the per leaf photosynthetic rate, dry root weight, and the per root single ginsenoside yield. The findings present a relatively low-cost approach for optimising the light environment of ginseng cultivated in farmland and other crops in large-scale agricultural settings.

Fake News and Cinema: film analysis in Europe and the United States

How does cinema reflect the reality of fake news? This paper answers this question. To the existing studies on cinema and journalism we want to add, under a qualitative analysis, the following point of view: those information professionals who defend professional malpractice because it is what the public demands. We understand qualitative methodology as the action of giving the film pieces analysed the category of primary source. We understand primary sources as those in which the data come directly from the population or a sample of the population (Torres, Paz and Salazar, 2014, p. 3). In this case, we are not talking about people, but about films.The viral is present in news consumers who, despite having more capacity to communicate than ever, are victims and, at the same time, part of the problem in the rapid spread of fake news. On the one hand, the audience is a victim because their right to be informed with a quality news product is being violated. Secondly, it is also part of the problem. It is not possible for malicious information to have a strong influence on society if there is no audience to consume it. That is, without a prior critical analysis of the product they are consuming. The films analysed have shown us that the population must assume certain responsibilities in order to avoid the disastrous consequences of fake news.

Levitation force measurement and characteristics analysis of double sided high temperature superconducting thin film device

In this paper, the levitation characteristics of double sided high temperature superconducting (HTS) thin film device is proposed and measured. Based on the unique advantages such as, passive self-stable levitation, higher payload, lower energy consumption, less maintenance cost, etc., HTS-magnetic levitation (maglev) technology has been applied in the traditional fields (rail transit and energy storage fields) and novel fields (astrophysics, space station microgravity, vibration isolation fields). As the key core components, HTS device should meet the requirements of volume, weight and cost, to improve the system operation efficiency. Thus, considering the low profile, miniaturization and lightweight characteristics of the double sided YBa2Cu3O7-x (YBCO) thin film, we measured its levitation and relaxation characteristics. Meanwhile, we also designed the YBCO thin film with meander-lines, to explore the levitation characteristic evolution mechanism. It can be found from the experimental results that, the single piece of YBCO thin film with/without meander-lines can offer the levitation force more than 400 mN and 800 mN, respectively. The signature of this work is that the double sided YBCO thin film has the potential to be employed as the core device in the special application fields (such as astrophysics and space station), to supply the sufficient micro levitation force in limited volume and weight.

Hydrogel‐Assisted Electrokinetics for High‐Resolution and Non‐invasive Flow Monitoring in Microfluidic Chips†

Comprehensive SummaryConvenient non‐invasive flow monitoring would facilitate the operation and control in microfluidic chips, but is challenging due to the small space of microchannels and complex operation required in traditional optical methods. In this work, we propose a novel non‐invasive strategy to probe microfluidic flows via streaming potential phenomenon. By sealing one side of the microchannel with a piece of hydrogel film, streaming potential inside the channel can be clearly detected by electrodes at outer surface of the hydrogel due to ion diffusion in the hydrogel. Flow is detected without sensors contacting with the internal liquid. Moreover, the electrodes shape like a tiny probe, which can move around mapping the flow distribution in a chip with the spatial resolution of 1 mm and flow rate detection limit of 3 μL·min–1. Bubbles inside the channels can also be detected, due to the fluctuation of streaming voltage when gas‐liquid interface flows through the electrode, showing an easy and potential way for multi‐functional flow monitoring in microfluidic chips.

Investigation of the Dosimetry Characteristics of the GAFCHROMIC® EBT3 Film Response to Alpha Particle Irradiation

The purpose of this study was to investigate the dosimetric characteristics of the GAFCHROMIC® EBT3 film responding to alpha particle irradiation. Unlaminated GAFCHROMIC® EBT3 film pieces, were irradiated with a 30.055 kBq 241Am alpha source, at eight different dose levels, between 0 and 509 Gy. The irradiations were performed inside an enclosed box. Epson Expression 10000 XL scanner in transmission mode was used to digitize irradiated films 24 hours post-irradiations as 16-bit RGB images in tagged image file format (TIFF). Optical density (OD) values were obtained by following the OD theorem. Raw and normalized pixel values (PVnorm) from the red, green, and blue colour channels were sampled from a 3 × 3 mm2 region of interest. Calibration curves were created for both data sets (OD and PVnorm) and were fit accordingly. Monte Carlo simulations with the Geant4 toolkit were performed to establish a dose rate at the point within the sensitive layer of the film. An alpha dosimetry protocol for EBT3 films was obtained from the Monte Carlo calculated dose rate and dose calibration curves for alpha radiation were created. It is necessary to extend this study for different film types and compare to photon dosimetry calibration curves.

Statistical Characteristics of Droplets Formed due to the “Bag Breakup” Fragmentation Event at the Interface between Water and High-Speed Air Flow

Abstract Recent studies indicate that the dominant mechanism for generating sprays in hurricane winds is a “bag breakup” fragmentation. This fragmentation process is typically characterized by inflation and consequent bursting of short-lived objects, referred to as “bags” (sail-like pieces of water film surrounded by a rim). Both the number of spray droplets and their size distribution substantially affect the air–sea heat and momentum exchange. Due to a lack of experimental data, the early spray generation function (SGF) for the bag breakup mechanism was based on the assumed similarity with resembling processes. Here we present experimental results for the case with a single isolated bag breakup fragmentation event. These experiments revealed several differences from similar fragmentation events that control the droplet sizes, such as secondary disintegration of droplets in gaseous flows and bursting of bubbles. In contrast to the bubble bursting, the film thickness of the bag canopy is not constant but is random with lognormal distribution. Additionally, its average value does not depend on the canopy radius but is determined by the wind speed. The lognormal size distribution of the canopy droplets is observed in conjunction with the established mechanism of liquid film fragmentation. The rim fragmentation results in two types of droplets, and their size distribution has been found to be lognormal distribution. The constructed SGF is verified by comparing it with experimental data from the literature. The perspectives of transferring the results from laboratory to field environment have also been discussed. Significance Statement The “bag breakup” fragmentation is the dominant mechanism for generating spray in hurricane winds. The number and the sizes of the spray droplets substantially affect the heat transport from the ocean to the atmosphere and, thereby, the development of hurricanes. This paper presents experimental data and analysis that demonstrate how droplet formation occurs during bag breakup fragmentation. It also shows analysis of the quantity and size of droplets formed during a single fragmentation event. This work demonstrates how obtained experimental results can be applied to real field conditions in the context of hurricane prediction models.

Constructing origami power generator from one piece of electret thin film and application in AI-enabled transmission line vibration monitoring

One of the crucial issues for applying electret/triboelectric power generators in the Internet of Things (IoT) is to take full advantage of specific high voltage signals and enable self-powered sensing. Therefore, inspired by Miura-origami, we present an innovative origami power generator (OPG) constructed from only one piece of electret thin film. The Miura-origami architecture realizes a generator with excellent deformability and stretchability and makes it unnecessary for any auxiliary support structure during the compress-release cycle. Various parameters of the generator are intensively investigated, including the excitation accelerations, excitation displacements, numbers of power generation units and deformation degree of the device. When stimulated with 5.0 g acceleration at 15 Hz frequency, the generator with 8 generation units can obtain an instantaneous peak-to-peak voltage and a remarkable optimum peak power of 328 V and 2152 μW at 50 MΩ, respectively. In addition, the regulable shape and multiple generation modes of the device greatly improve its applicability in various vibration energy collection requirements. Based on the above results, a hexagonal electret generator integrated with six-phase OPGs is developed as a “Buoy on Sky,” after which the signal waveforms generated from internal power generators are recognized with 92% accuracy through a neural network algorithm that identifies the vibration conditions of transmission lines. This work demonstrates that a fusion of origami art and energy conversion techniques can achieve a multifunctional generator design satisfying the requirements for IoT applications.

Linear and nonlinear guided wave based debonding monitoring in CFRP-reinforced steel structures

When carbon fibre reinforced polymer (CFRP) is employed to reinforce the damaged steel structures, the debonding problem existing at the interfaces between two materials can be fatal for the retrofitted structures. As a result, identifying the debonding from its earliest stage can be helpful, which leaves sufficient time for further maintenance actions. Based on the current research findings, the linear guided wave based detection technique can provide a good measure for identifying the existence of gross damage, but it is not as sensitive as the nonlinear guided wave method when detecting the micro damage. In order to develop an effective way to continuously monitor the debonding growth from its initiation, both linear and nonlinear methods were investigated and compared in terms of debonding evaluation in this paper. A fatigue test was carried out on a CFRP-reinforced steel structure, in which a small piece of Teflon film was artificially inserted, to facilitate the debonding development. The correlation coefficient (CC) as well as the damage index (DI) between the benchmark signals and signals after certain cycles of fatigue test were established using both methods. Furthermore, the probability based imaging method was applied to individually show the possible debonding areas based on the data from each method. The finding demonstrated different damage detection sensitivities between the linear and nonlinear guided wave based methods and verified the feasibility of monitoring the whole debonding process by combining these two methods, namely, the nonlinear method for debonding initiation and linear method for debonding growth monitoring.

Online study of the plasma-accelerated aging process and toxicity of polyethylene terephthalate

Plastic aging occurs in all environmental media and affects their environmental behavior and toxicity. In this study, non-thermal plasma was applied to simulate the aging process of plastics, with polyethylene terephthalate (PET-film) being used as a model. The surface morphology, mass defects, toxicity of aged PET-film and the generation of airborne fine particles were comprehensively characterized. The surface of PET films began to become rough and then gradually became uneven, generating pores, protrusions and cracks. The toxicity of aged PET films was assessed in Caenorhabditis elegans which significantly reduced head thrashing, body bending and brood size. A single particle aerosol mass spectrometry instrument was used to characterize the size distribution and chemical composition of airborne fine particles in real-time. Few particles were observed during the first 90 min, while the generation of particles accelerated significantly after aging time beyond 90 min. For two pieces of PET film with surface area of 5 cm2, during the 180 min, at least 15113 ± 153 fine particles were generated, having a unimodal size distribution with a peak of 0.4 µm. The main components of these particles included metals, inorganic non-metals, and organic components. The results provide useful information on plastic aging and are beneficial in assessing the potential environmental risks.

Detection of Residual Film on the Field Surface Based on Faster R-CNN Multiscale Feature Fusion

After the residual film recycling machine recovers the film, some small pieces of the film will remain on the surface of the field. To solve the problem of collecting small pieces of film, it is necessary to develop a piece of intelligent picking equipment. The detection of small pieces of film is the first problem to be solved. This study proposes a method of an object detection algorithm fusing multi-scale features (MFFM Faster R-CNN) based on improved Faster R-CNN. Based on the Faster R-CNN model, the feature pyramid network is added to solve the problem of multiscale change of residual film. The convolution block attention module is introduced to enhance the feature extraction ability of the model. The Soft-NMS algorithm is used instead of the NMS algorithm to improve the detection accuracy of the model in the RPN network. The experimental results show that the model is able to effectively detect surface residual film in complex environments, with an AP of 83.45%, F1-score of 0.89, and average detection time of 248.36 ms. The model is compared with SSD and YOLOv5 under the same experimental environment and parameters, and it is found that the model not only ensures high-precision detection but also ensures real-time detection. This lays the theoretical foundation for the subsequent development of field surface residual film intelligent picking equipment.

Effects of residual plastic film on crop yield and soil fertility in a dryland farming system

Plastic film mulch in agricultural production becomes essential to maintaining crop yields in arid and semiarid areas. However, the presence of residual film in farmland soil has also drawn much attention. In this study, three experiments were conducted. The first two experimental designs included 0, 450, 1 350, and 2 700 kg ha−1 of residual film pieces of approximately 5 cm side length added to field soil (0–20 cm soil depth) for seven years and added to pots for four years. In the third experiment, 1 350 kg ha−1 of the residual film with different side lengths (2–5, 5–10, 10–15, and 15–20 cm) was added to field soil for six years to explore the effect of residual film fragment size on soil nutrients, soil microorganisms, crop growth and yields. The residual film had little effect on the soil moisture at a field depth of 0–2 (or 0–1.8) m. There were no significant effects on organic carbon, total nitrogen, inorganic nitrogen, total phosphorus or available phosphorus in the 0–20 cm soil layer. The presence of residual film decreased the richness and diversity of the bacterial community of the surface soil of the residual film, but it had no significant effect on the microbial community of the non-surface soil. The emergence rates of wheat and lentils occasionally decreased significantly with different amounts of residue fragments added to the field. At 450–2 700 kg ha−1, the residual film reduced the plant height and stem diameter of maize and significantly reduced the shoot biomass of harvested maize by 11–19%. The average yields of maize and potato over the seven years decreased, but there were almost no significant statistical differences among the treatments. These results provide important data for a comprehensive scientific understanding of the effects of residual film on soil and crops in dryland farming systems.

Ion irradiation induced direction of collapsed hard-magnetization axis in thin Co films

A number of polycrystalline films feature distinct sharp peaks in the angular variations of their in-plane major-loop remanent magnetization and coercivity, centered ${90}^{\ensuremath{\circ}}$ off the easy-axis position, a property referred to as hard-axis collapse. In such systems a striking phenomenon, recoil-curve overshoot (RCO), recoil magnetization branches that lie outside the major loop, was recently reported, resulting in a significantly greater recoil loop area compared with that of the respective major loop. In the present work pieces of polycrystalline magnetron-sputtered Co films were subjected to ${\mathrm{Ne}}^{+}$ bombardment in vacuum at different ion fluences in the presence of magnetic field ${H}_{ib}$ applied along different in-plane directions. Ion irradiation at a certain fluence range results in films with easy-magnetization directions parallel to that of ${\mathbf{H}}_{\mathbf{ib}}$. Moreover, the same holds for posterior sequential irradiations. The films' hard-magnetization axes are always collapsed, accompanied by significant RCO as well. The analysis and interpretation of our data strongly indicate that both hard-axis collapse and RCO result predominantly from a domain splitting when the measurement magnetic field is nearly perpendicular to the grain's easy axis during demagnetization.

The effect of common dental fixtures on treatment planning and delivery for head and neck intensity modulated proton therapy.

Proton treatment plan perturbation by common dental fixtures such as amalgams (Am) and porcelain-fused-to-metal (PFM) crowns has, to date, been uncharacterized. Previous studies have been conducted to determine the physical effect of these materials within the beam path for single spots, but their effects on complex treatment plans and clinical anatomy have not yet been quantified. The present manuscript aims to study the effect of Am and PFM fixtures on proton treatment planning in a clinical setting. An anthropomorphic phantom with removable tongue, maxilla, and mandible modules was simulated on a clinical computed tomography (CT) scanner. Spare maxilla modules were modified to include either a 1.5mm depth central groove occlusal amalgam (Am) or a porcelain-fused-to-metal (PFM) crown, implanted on the first right molar. Modified tongue modules were 3D printed to accommodate several axial or sagittal oriented pieces of EBT-3 film. Clinically representative spot-scanning proton plans were generated in Eclipse v.15.6 using the proton convolution superposition (PCS) algorithm v.15.6.06 using a multi-field optimization (MFO) technique with the goal of delivering a uniform 54Gy dose to a clinical target volume (CTV) typical of a base-of-tongue (BoT) treatment. A typical geometric beam arrangement of two anterior oblique (AO) beams and a posterior beam was employed. Plans optimized without any material overrides were delivered to the phantom A) without implants; B) with Am fixture; or C) with PFM crown. Plans were also reoptimized and delivered with inclusion of material overrides to equate relative stopping power of the fixture with that of a previously measured result. Plans exhibit slightly greater dose weight towards AO beams. The optimizer accounted for inclusion of fixture overrides by increasing beam weights to the beam closest to the implant. Film measurements exhibited cold spots directly within the beam path through the fixture in plans with and without overridden materials. Cold spots were somewhat mitigated in plans including overridden materials in the structure set but were not entirely eliminated. Cold spots associated with Am and PFM fixtures were quantified at 17% and 14% for plans without overrides, respectively, and 11% and 9% with using Monte Carlo simulation. Compared with film measurements and Monte Carlo simulation, the treatment planning system underestimates the dose shadowing effect in plans including material overrides. Dental fixtures create a dose shadowing effect directly in line with the beam path through the material. This cold spot is partially mitigated by overriding the material to measured relative stopping powers. Due to uncertainties in modeling perturbation through the fixture, the magnitude of the cold spot is underestimated using the institutional TPS when compared to measurement and MC simulation.