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The contact quality between Si and the rear electrode and the passivation of Si play crucial roles in efficient organic/Si hybrid solar cells, especially for the open-circuit voltage (VOC). Herein,...

The optical and electrical properties of the blending organic film poly(3,4-ethylenedioxy-thiophene):poly(styrenesulfonate) (PEDOT:PSS) are strongly affected by its morphology, resulting in the performance variation in Si/organic hybrid solar cells. Here, a facile postsolvent treatment is used to tailor the vertical morphology of PEDOT:PSS by introducing a nonpolar solvent. X-ray photoelectron spectroscopy depth-profiling measurements show that the distribution of PEDOT and PSS on the surface of n-type Si can be changed by nonpolar solvent n-hexane (NHX) treatment, where more PSS aggregate at the bottom of the blend film and more PEDOT float up to the top, as compared with the reference sample. As a result, after NHX treatment, the average lifetime of the Si/organic films is increased from 152 μs for untreated samples to 248 μs for NHX-treated ones because of the better passivation effect of PSS on Si. Moreover, the transmission line model measurements indicate that the contact resistance (RC) of PEDOT:PSS film and the Ag electrode is decreased for better charge collection after NHX treatment. Eventually, the best power conversion efficiency (PCE) of 13.78% for NHX-treated planar solar cells is obtained, much higher than the PCE (with best of 12.78%) of reference devices without nonpolar solvent treatment. Our results provide a facile method to tailor the vertical morphology of the PEDOT:PSS in Si/organic hybrid solar cells.

Many structures in civil engineering are symmetrical. Crack detection is a critical task in the monitoring and inspection of civil engineering structures. This study implements a lightweight neural network based on the YOLOv4 algorithm to detect concrete surface cracks. In the extraction of backbone and the design of neck and head, the symmetry concept is adopted. The model modules are improved to reduce the depth and complexity of the overall network structure. Meanwhile, the separable convolution is used to realize spatial convolution, and the SPP and PANet modules are improved to reduce the model parameters. The convolutional layer and batch normalization layer are merged to improve the model inference speed. In addition, using the focal loss function for reference, the loss function of object detection network is improved to balance the proportion of the cracks and the background samples. To comprehensively evaluate the performance of the improved method, 10,000 images (256 × 256 pixels in size) of cracks on concrete surfaces are collected to build the database. The improved YOLOv4 model achieves an mAP of 94.09% with 8.04 M and 0.64 GMacs. The results show that the improved model is satisfactory in mAP, and the model size and calculation amount are greatly reduced. This performs better in terms of real-time detection on concrete surface cracks.

Interlayers play important roles in elevating the efficiency of the organic solar cells (OSCs). It is generally believed that organic cathode interlayer (CIL) can form dipole at the interface to reduce the work function of the metal electrode and minimize the contact resistance between the active layer and electrode. However, in most cases, the interlayer materials are deposited onto an active layer by spin coating and the polar groups thus randomly distribute on the surface of the active layer. In this work, we adopted fluorinated polyethylene glycol (FSO-100, a commercialized surfactant) as cathode interlayer in OSCs and achieved remarkable performance enhancement. Scanning Kelvin probe microscopy (SKPM) and ultraviolet photoelectron spectrometer (UPS) results prove that FSO-100 effectively decrease the work function of the metal electrode. Angle resolved XPS (ARXPS) shows that fluorinated alkyl chains on FSO-100 prefer to spontaneously aggregate on one side and thus result in highly ordered ethylene glycol chains, which enhance the dipole strength as well as improve the device performance, even much better than device with polyethylene glycol (PEG) as CIL. These results demonstrate that introducing a fluorinated alkyl chain on CIL is an effective strategy to promote the molecular orientation, as well as improve the electrode modification ability of CIL.

A novel educational tool helps teach intestinal absorption in physiology-We have designed an interesting educational tool to help sophomores learn intestinal absorption in physiology course. In the study group (2019), 51 sophomores from biomedical engineering were encouraged to learn the intestinal absorption knowledge through reading materials and group discussion. Then, using the form of flipped class, they stepped on the podium and simulated and explained the absorption processes with designed paper props as educational tool. In contrast, the control group (2018), 52 sophomores from the same specialty had taken the same professional courses before. The result of theoretical test showed the average score in the study group was higher than that in the control group. The questionnaire analysis showed the positive role of the education tool in their learning efficacy. To sum up, using our tool has achieved better teaching effects than the traditional lecture.

Cyclic volatile methylsiloxaes (cVMSs), namely hexamethylcyclotrisiloxane (D3), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6), were studied for a typical indoor environment of male and female dormitories in the campus of Dalian Maritime University (DMU) in China. An empty, frit-fitted SPE cartridge was placed on top of an Isolute ENV + cartridge, sampling cVMSs in particulate and gas phases, respectively. The highest concentration of D3, D4, D5, and D6 was 190, 460, 37,000, and 670 ng m−3, respectively. All cVMSs, especially D5, were higher in female dormitories than that in male dormitories. Emission rate from different sources of cVMSs in dormitories was calculated from a survey of the use of personal care products (PCPs) by students living in the dormitory during the sampling period. The mean emission rate (ER, mg·d−1) of D4 and D5 in male dormitories was 0.12 ± 0.01 and 0.49 ± 0.03 mg d−1, respectively, and that in female dormitories was 0.21 ± 0.05 and 46 ± 17 mg d−1, respectively. Then, we modified an existing mass balance model to predict the indoor air levels of D4 and D5 in both male and female dormitories based on the usage of PCPs. There was a good agreement for D4 and D5 concentrations in female dormitories between modeled and measured concentrations with the ratio of predicted to measured values to be 1.5 and 1.2, respectively, which indicated that use of PCPs was the main source of cVMSs in university dormitories.

Unrecognized spatial disorientation (SD) which is intimately linked with brain cognitive function is always a fatal issue for the safety of pilots. To explore its effects on human brain cognitive functions, electroencephalography (EEG) functional network analysis methods were adopted to examine topological changes in the connection of cognitive regions when experiencing unrecognized SD. Twelve male pilots participated in the study. They were subjected to a SD scene, namely visual rotation, which evoked unrecognized SD. For the main EEG frequency intervals, the phase lag index (PLI) and normalized mutual information (NMI) were calculated to quantify the EEG data. Then weighted connectivity networks were constructed and their properties were characterized in terms of an average clustering coefficient and global efficiency. A T-test was performed to compare PLI, NMI and network measures under unrecognized SD and non-SD conditions. It indicated a weak functional connectivity level in the theta band under unrecognized SD based on the significant decrease of mean values of PLI and NMI (p

Atmospheric concentrations of α- and γ-hexachlorocyclohexanes were measured once a week in Dalian throughout 2008, using a high-volume air sampler, to estimate diurnal, monthly and seasonal variations. Multiple regression analysis was used to estimate the impact of selected meteorological conditions on atmospheric concentrations of hexachlorocyclohexanes and to identify the potential source regions. Overall, α- and γ-hexachlorocyclohexanes were mainly associated with the gas phase, with an annual mean gas-phase concentration of 36 ± 30 and 10 ± 9.8 pg m −3 respectively. On the other hand, mean particle (PM 10 ) associated concentrations throughout the year were 1.9 ± 2.4 and 0.46 ± 0.43 pg m −3 respectively. Gas-phase concentration of α- and γ-hexachlorocyclohexanes peaked in the autumn season whereas highest concentrations in the particle phase were measured in spring. Ratio of α-/γ-isomer ranged from 3.7 to 7.4 in the gas phase which was close to the ratio in technical hexachlorocyclohexanes (5–7). In the particle-associated phase this ratio ranged from 1.2 to 3.8, with the exception of daytime samples in spring (up to 16) and summer seasons (up to 14) and this exception could be due to the isomerization from γ- to α- in ambient air, at least partly resulted from the impact of sunlight. Regression analysis showed that, at the sampling site, concentrations of α- and γ-hexachlorocyclohexanes in the gas phase were both elevated with increasing temperature and wind speed, whereas in the particle-associated phase their concentrations tended to remain stable.

The security issues are extremely popular in the virtual community VC environment because of the uncertainties. Many works use trust mechanisms as the enhancement. However, trust has flaws in some aspects, making it uncontrollable. Discussed in this paper is the reason that risk is chosen to evaluate individual's credit. Then, risk in VC environment has several properties that are helpful to understand the relationship between VC and members. A new concept is that the capacity of risk absorbing is introduced to make the model more reasonable for usual scenario. In order to compute the capacity of risk absorbing problem, shapley value approach is utilized to equalize the risk of individuals who join the game in series. The evaluation result can provide VC computed evidence to control the individual's behavior. Copyright © 2014 John Wiley & Sons, Ltd.

Heterogeneous network selection is a popular topic with the rapid development of telecommunication technologies. Literatures employed different ways for solving the issue with drawbacks more or less especially neglecting the user preference and using much subjective configurations. This paper proposes a user preference scheme including realtime or non-realtime pursuit, money and battery consumption concern and non-specific requirement. For front four modes, a technique for order preference by similarity to ideal solution based method with vote which reduces the subjectiveness is introduced. Then, a function-less and totally unsubjective method called directional distance function based data envelopment analysis method faces the non-specific requirement. Several examples test these two methods and the results support them.

A model is proposed to estimate the probability distribution of asset value based on the benefit effects as well as the risk effects of deposit insurance with the minimum cross-entropy principle. Three scenarios are constructed to depict situations with different dual effects of deposit insurance. The corresponding assets distribution functions are obtained accordingly. The results show that it is positively correlated between the supervision level and the risk aversion effects of deposit insurance. The increase of the deposit insurance premium moves the bank’s assets distribution to the right side although not significantly. The asset probability distributions estimated in this paper can be taken as a reference for banks to choose the proper credit investment projects.

Internet of Things IoT is well studied from many aspects; however, data transmission in a large-scale constructed IoT network is still an open topic. In this paper, the problems of channel congestion caused by mass data transmission are discussed respectively from different perspectives. Then, a multiple layer solution is proposed, pointing to each layer including data processing architecture, data dimension reduction, data abandon protocol, and spectrum sharing. In the architecture layer, a combined scheme with cloud computing and sea computing is introduced. Context awareness and granular computing is exploited to implement the data dimension reduction. And cognitive protocol is involved with type of service, which drops certain data to guarantee the entire network connectivity. Then, a principal-agent theory based two-step game model is proposed with the consideration of cooperation and price coefficient, which affect the secondary user's choice and primary user's profit. Some incomplete information is assumed as random variables so that certainty equivalent is introduced in the model. A simple scenario shows how the data dimension reduction works and how simulations for data abandon protocol and spectrum sharing test the two parts, respectively. Copyright © 2012 John Wiley & Sons, Ltd.

Internet of Things and broadband communication are promoting the pervasive mobile services with their advanced features. However, security problems baffled the development. This paper proposes a trust model to protect the user's security. The billing or trust operator works as an agent to provide a trust authentication for all the service providers. The services are classified by sensitive value calculation. With the combined location-aware and identity-aware information and authentication history, the user's trustiness for corresponding service can be obtained. For decision, three trust regions are divided and referred to three ranks as follows: high, medium and low. The trust region tells the customer which authentication methods should be used for access. Penalty coefficient is also involved for forbidding force-crack. Copyright © 2012 John Wiley & Sons, Ltd.

This paper applies principal-agent theory to research into the incentive compatibility problems of the independent directors (IDs). The traditional fixed-pay system could preserve the independence of IDs, however, lacking of in-centives, the performance-related incentive mechanisms have great impact on IDs' independence which is the core of the system. This paper considers reputation incentive mechanism (RIM) as an effective way to solve this dilemma. The results, after our study, show that appropriate RIM can maintain IDs' independence as well as their incentive compati-bility. Furthermore, taking the market-signal theory as reference, this paper sets up a model to introduce another func-tion of RIM, which can help the company to identify the different roles of IDs.

Galvanic vestibular stimulation (GVS) can be used to study the body’s response to vestibular stimuli. This study aimed to investigate whether postural responses to GVS were different between pilots and the general populace. Bilateral bipolar GVS was applied with a constant-current profile to 12 pilots and 12 control subjects via two electrodes placed over the mastoid processes. Both GVS threshold and the center of pressure’s trajectory (COP’s trajectory) were measured. Position variability of COP during spontaneous body sway and peak displacement of COP during GVS-induced body sway were calculated in the medial-lateral direction. Spontaneous body sway was slight for all subjects, and there was no significant difference in the value of COP position variability between the pilots and controls. Both the GVS threshold and magnitude of GVS-induced body deviation were similar for different GVS polarities. GVS thresholds were similar between the two groups, but the magnitude of GVS-induced body deviation in the controls was significantly larger than that in the pilots. The pilots showed less GVS-induced body deviation, meaning that pilots may have a stronger ability to suppress vestibular illusions.

To improve the usage rate and quality of emergency equipment in the hospital, the emergency equipment management was studied. The specialized management and common use of emergency equipment in a hospital was analysed with statistical methods. The usage rate, economic effectiveness and management quality of the equipment were evaluated. Based on the practical experience, the superiorities of the specialized management and common use of emergency equipment in hospitals were summarized, and the inferior positions and their improvement approaches were proposed. As a result, the hospital resource allocation was optimized and the equipment management level was improved by using the specialized management and common use of emergency equipment in the hospital.

Three algorithms of electrical impedance tomography (EIT) are studied in this paper. The image resolution, anti-noise property and computation rapidity of the reconstruction algorithms are compared. As a result, it shows that back-projection algorithm has good anti-noise property, that NOSER algorithm generates images with good resolution, and that sensitivity matrix algorithm has moderate property.

This paper points to the dynamic spectrum sharing problem in cognitive radio network and analyzes the behavior of primary user (PU) and secondary user (SU). The relationship between PU and SU can be treated as principal and agent. Then, a principal-agent theory based two-step game model is proposed with the consideration of cooperation and price coeffcient which effect the SU's choice and PU's profit. Further, some incomplete information is assumed as random variables so that certainty equivalent is introduced in the model. Both cooperation and price effect are simulated at the end.

Internet of Things (IoT) is an upcoming network technology well studied by many researchers. Mass applications and terminal nodes with heterogenous network connection make the tremendous scale of data process extremely difficult. A combined architecture with Cloud Computing and Sea Computing is proposed. Deluge Computing, a new concept, using Adaptive Coding and Modulation and Granular Computing aims to release the pressure of data process when data deluge bursts. Granular Computing is emphasized in this architecture for data reduction.

Internet of Things (IoT) and B3G/4G communication are promoting the pervasive mobile services with its advanced features. However, security problems are also baffled the development. This paper proposes a trust model to protect the user's security. The billing or trust operator works as an agent to provide a trust authentication for all the service providers. The services are classified by sensitive value calculation. With the value, the user's trustiness for corresponding service can be obtained. For decision, three trust regions are divided, which is referred to three ranks: high, medium and low. The trust region tells the customer, with his calculated trust value, which rank he has got and which authentication methods should be used for access. Authentication history and penalty are also involved with reasons., Comment: IEEE/ACM Internet of Things Symposium (IOTS), in conjunction with GreenCom 2010, IEEE, Hangzhou, China, December 18-20, 2010

Since the principal-agent relationship ex- ists between independent directors(IDs) and share- holders, the incentive compatibility problems which are still unsolved should be given more attention. The traditional fixed-pay system could preserve the independence of IDs, however, lack of incentives; the performance-related incentive mechanisms have great impact on IDs' independence which is the core of the system. This paper consider the reputation incentive mechanism(RIM) as an effective way to solve this dilemma. Appropriate RIM can maintain IDs' independence as well as their incentive compatibility. Index Terms—reputation incentive mechanism; in- dependent directors; principal-agent relationship

Aims Brachyury overexpression has been reported in various human malignant neoplasms, but its expression and function in hepatocellular carcinoma progression and metastasis remains unknown. The present study aimed to evaluate the critical role of Brachyury in HCC metastasis. Methods The expression of Brachyury in human HCC (SMMC7721, HepG2, FHCC98, and Hep3B) and control cell lines was analyzed using quantitative reverse-transcriptase polymerase chain reaction and immunoflourence methods. Cancerous tissues collected from patients with HCC (n = 112) were analyzed using immunohistochemical method; a microarray analysis of HCC tissues was performed to explore the clinicopathological variables of HCC. The migratory and invasive capacities of Brachyury-SMMC7721 and Brachyury-HepG2 transfected cells were evaluated using in vitro scratch wound healing and Matrigel invasion assays, respectively. Further, six-week-old male BALB/c nude mice (n = 10) model was used in vivo assay. Results Elevated expression of Brachyury was detected in HCCs (62.5%) compared with that in adjacent nontumorous tissues. Clinicopathological analysis revealed a close correlation of Brachyury expression with distant metastasis and poor prognosis of HCC. Overexpression of Brachyury promoted epithelial-mesenchymal transition (EMT) and metastasis of HCC cells in vitro and in vivo. Brachyury overexpression enhanced Akt activation by inhibiting phosphatase and tensin homolog (PTEN), which led to subsequent stabilization of Snail, a critical EMT mediator. Conclusion The study findings suggest that elevated Brachyury facilitates HCC metastasis by promoting EMT via PTEN/Akt/Snail-dependent pathway. Brachyury plays a pivotal role in HCC metastasis and may serve as a novel prognostic biomarker and therapeutic target.