TiO2 is the most widely used electron transport layer (ETL) in high performance perovskite solar cells (PSCs). However, TiO2 often induces a rapid decay in performance under ultraviolet (UV) light illuminations. So, high performance ETL is urgently needed for PSCs. Here, a new kind of Nb2O5 nanoparticles ETL was developed for fabricating efficient planar PSCs with excellent UV stability. The matched band alignment between perovskites and Nb2O5 promotes electron injection at the ETL/perovskite interface, and decreases the energy barrier for electron injection. Decreased energy loss during electron transfer from perovskite to Nb2O5 and lower recombination rates in the devices contribute to the improved open-circuit voltage (V oc) of PSCs on Nb2O5 compared to devices on TiO2. Power conversion efficiency (PCE) surpassing 20% with a high V oc of 1.19 V was demonstrated for planar PSCs with Nb2O5 ETL. The unencapsulated devices based on Nb2O5 retained 93% of their initial short-circuit current density (J sc) after 10 h exposure to concentrated 365 nm UV light (46 mW/cm2), versus 40% for devices based on TiO2, which was attributed to the excellent chemical stability nature of Nb2O5 under UV light.

Xerostomia induced by radiotherapy is a common toxicity for head and neck carcinoma patients. In this study, the deformable image registration of planning computed tomography (CT) and weekly cone‐beam CT (CBCT) was used to override the Hounsfield unit value of CBCT, and the modified CBCT was introduced to estimate the radiation dose delivered during the course of treatment. Herein, the beams from each patient's treatment plan were applied to the modified CBCT to construct the weekly delivered dose. Then, weekly doses were summed together to obtain the accumulated dose. A total of 42 parotid glands (PGs) of 21 nasopharyngeal carcinoma patients were analyzed. Doses delivered to the parotid glands significantly increased compared with the planning doses. V20, V30, V40, Dmean, and D50 increased by 11.3%, 28.6%, 44.4%, 9.5%, and 8.4% respectively. Of the 21 patients included in the study, eight developed xerostomia and the remaining 13 did not. Both planning and delivered PG Dmean for all patients exceeded tolerance (26 Gy). Among the 21 patients, the planning dose and delivered dose of Dmean were 30.6 Gy and 33.6 Gy, respectively, for patients with xerostomia, and 26.3 Gy and 28.0 Gy, respectively, for patients without xerostomia. The D50 of the planning and delivered dose for patients was below tolerance (30 Gy). The results demonstrated that the p‐value of V20, V30, D50, and Dmean difference of the delivery dose between patients with xerostomia and patients without xerostomia was less than 0.05. However, for the planning dose, the significant dosimetric difference between the two groups only existed in D50 and Dmean. Xerostomia is closely related to V20, V30, D50, and Dmean.

Two-dimensional MoS2 attracts much attention because of its potential application in electronic and optoelectronic devices at present. However, the preparation of large and uniform single crystal MoS2 nanosheets is still a challenge, which restricts its further application. Herein, monolayer single crystal MoS2 nanosheets with large and uniform grain size have been synthesized by chemical vapor deposition using a double-tube system. Within the main growth area, the grain size reaches 146 μm on the substrate of SiO2/Si, and the portion of MoS2 nanosheets with grain size between 50 μm and 100 μm is up to 78%. Meanwhile, the grain size keeps constant in the direction perpendicular to the tubes and changes slightly in the parallel direction. This is attributed to the concentration distribution of intermediate product MoO3−x in the one-side sealed inner tube set in a quartz tube, i.e., the double-tube system, which provides a way to the controllable and uniform synthesis of large monolayer single crystal MoS2 nanosheets.

Hydrodynamic retention is one of the contributors to polymer loss in porous media. In this study, effects of flow rate, polymer molecular weight, and core permeability on hydrodynamic retention were investigated. To quantify hydrodynamic retention, injection of two identical polymer banks at different rates separated by 100 pore volumes of brine flushing was performed. Three HPAM polymers with molecular weights of 6 -8 million, 12 million, and 20 million Daltons were tested in a 135 mD sandstone core and xanthan polymer with molecular weight of 2-2.5 million Daltons was tested in an 87 mD sandstone core. The retention of 6 -8 million Daltons HPAM in a 1,650 mD sandstone core was also measured. Polymer retention in a fresh core was first measured at low injection rate of 3.11 ft/day. Then, 100 PV of 2% NaCl brine was injected to displace all the mobile polymer molecules in the core till pressure drop across the core became stable. Hydrodynamic retention at elevated flow rates was determined after the completion of retention at lower rates and comparisons with the initial polymer retention were made.Retention of 96.1 g/g in the 135 mD core was detected for the 6 -8 million HPAM at a flow rate of 3.11 ft/day. Increase of flow rate from 3.11 ft/day to 6.22 ft/day and 12.4 ft/day resulted in incremental retention of 2.27 g/g and 5.38 g/g, respectively. The injection of a higher molecular weight polymer at the same rate was performed after retention was satisfied with a lower molecular weight polymer. It was found the degree of hydrodynamic retention was greater when higher molecular weight polymers were injected. When core permeability was changed from 135 mD to 1,650 mD, both the initial and hydrodynamic retention were dramatically decreased. The initial retention of xanthan was 66.7 g/g in an 87 mD sandstone core, which was smaller compared to the retention of HPAM in the similar core. However, hydrodynamic retention measurements of xanthan gives 3.26 g/g and 6.38 g/g increments with the increase of flow rate from 3.11 ft/day to 6.22 ft/day and 12.4 ft/day, which suggested that the retention of xanthan is slightly more sensitive to the change of injection rate than HPAM. This study also implied that measurement of residual resistance factor after polymer injection should be completed after sufficient brine flushing (around 100 PV), otherwise, an overestimated residual resistance factor might be provided.

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Purpose: Leukemia is a lethal disease that is harmful to bone marrow and overall blood health. The classification of white blood cell images is crucial for leukemia diagnosis. The purpose of this study is to classify white blood cells by extracting discriminative information from cell segmentation and combining it with the fine-grained features. We propose a hybrid adversarial residual network with support vector machine (SVM), which utilizes the extracted features to improve the classification accuracy for human peripheral white cells. Methods: Firstly, we segment the cell and nucleus by utilizing an adversarial residual network, which contains a segmentation network and a discriminator network. To extract features that can handle the inter-class consistency problem effectively, we introduce the adversarial residual network. Then, we utilize convolutional neural network (CNN) features and histogram of oriented gradient (HOG) features, which can extract discriminative features from images of segmented cell nuclei. To utilize the representative features fully, a discriminative network is introduced to deal with neighboring information at different scales. Finally, we combine the vectors of HOG features with those of CNN features and feed them into a linear SVM to classify white blood cells into six types. Results: We used three methods to evaluate the effect of leukocyte classification based on 5000 leukocyte images acquired from a local hospital. The first approach is to use the CNN features as the input of SVM to classify leukocytes, which achieved 94.23% specificity, 95.10% sensitivity, and 94.41% accuracy. The use of the HOG features for SVM achieved 83.50% specificity, 87.50% sensitivity, and 85.00% accuracy. The use of combined CNN and HOG features achieved 94.57% specificity, 96.11% sensitivity, and 95.93% accuracy. Conclusions: We propose a novel hybrid adversarial-discriminative network for the classification of microscopic leukocyte images. It improves the accuracy of cell classification, reduces the difficulty and time pressure of doctors' work, and economizes the valuable time of doctors in daily clinical diagnosis.

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