A helical drive in-pipe robot based on compound planetary gearing

<div><p>The modern society is fuelled by very comprehensive grids of gas and liquid pipelines. In recent years, various in-pipe robots have been developed for inspection and maintenance tasks inside such pipes. In this paper, a novel in-pipe robot is proposed and developed for gas/oil well interventions at thousands of meters downhole. Due to the nature of such intervention, in-pipe robot design must be capable of carrying a very large payload, as large as 2500 N inside a pipe with diameter as small as 54 mm. The proposed design concept is based on a compound planetary gearing system. One of the major novelties of this design is the use of pipe wall as a ring gear for one stage of the compound planetary gear system; the other novelty is the generation of helical angle when the planetary gears are expanded to press on the pipe wall. The proposed concept is compact, efficient, and has never been reported before. In this paper, the helical angle, the velocity, and load capability of the proposed system will be analyzed. The load transportation capability of the proposed robot is also measured based on an experiment. Initial data have shown great potential in carrying large payloads.</p></div

Graphene Oxide-Based Carbon Interconnecting Layer for Polymer Tandem Solar Cells

Tandem polymer solar cells (PSCs), consisting of more than one (normally two) subcells connected by a charge recombination layer (i.e., interconnecting layer), hold great promise for enhancing the performance of PSCs. For an ideal tandem solar cell, the open circuit voltage (<i>V</i>_oc) equals to the sum of those of the subcells while keeping the short circuit current the same as the lower one, leading to an increased overall power conversion efficiency. The interconnecting layer plays an important role in regulating the tandem device performance. Here, we report that graphene oxide (GO)/GO-Cs (cesium neutralized GO) bilayer modified with ultrathin Al and MoO₃ can act as an efficient interconnecting layer in tandem PSCs to achieve a significantly increased <i>V</i>_oc, reaching almost 100% of the sum of the subcell <i>V</i>_ocs under standard AM 1.5 conditions

Additional file 1: Figure S1. of Down-regulation of the tumour suppressor Îş-opioid receptor predicts poor prognosis in hepatocellular carcinoma patients

KOR protein expression in HCC tissue and corresponding adjacent non-tumour tissue. (DOCX 1727 kb

Graphene Oxide by UV-Ozone Treatment as an Efficient Hole Extraction Layer for Highly Efficient and Stable Polymer Solar Cells

The hole extraction layer has a significant impact on the achievement of high-efficiency polymer solar cells (PSCs). Here, we report an efficient approach to direct UV-ozone treatment by larger device performance enhancement employing graphene oxide (GO). The dramatic performance enhancement of PSCs with the P3HT:PCBM blend as an active layer was demonstrated by the UV-ozone treatment of GO for 30 min: best power conversion efficiency (PCE) of 4.18%, fill factor of 0.63, <i>J</i>_sc of 10.94 mA cm^–2, and <i>V</i>_oc of 0.61 V, which are significantly higher than those of the untreated GO (1.82%) and highly comparable PEDOT:PSS-based PSCs (3.73%). In addition, PSCs with UV-ozone-treated GO showed a longer stability than PSCs with PEDOT:PSS. The significant enhancement of PCEs of PSCs can be attributed to the fact that ozone molecules can oxidize GO into CO₂ and leave highly conductive graphene particles. We suggest that this simple UV-ozone treatment can provide an efficient method for highly efficient GO hole extraction in high-performance PSCs

Toward a Diagnostic Method for Efficient Perovskite Solar Cells Based on Equivalent Circuit Parameters

The equivalent circuit model is one of the essential tools for revealing information about the material characteristics, working mechanisms, and operation state of perovskite solar cells. However, it is still challenging to accurately obtain the equivalent circuit parameters of the highly efficient solar cells with a power conversion efficiency more than 22%. In this work, we proposed a new scheme to estimate all the parameters of the high-performance solar cells only from their current–voltage curves by reasonably combining the traditional analytical method and the parameter optimization method. Then, we applied the proposed method to analyze the equivalent circuit parameters of a typical efficient perovskite solar cell under different light intensities and aging times. Through the parameters, we succeeded in bridging photovoltaic parameters and the structural, morphological, and optoelectronic changes of the solar cells. In particular, the proposed method is compatible with the notorious current–voltage hysteresis. To test the method further, it is compared with two typical approximate methods commonly used recently. By comparison, the proposed approach is simple, reliable, and insensitive to the initial values. Moreover, limitations and precautions for the traditional methods are given to ensure their effectiveness. Finally, we note that the proposed approach of this work provides a feasible solution to conduct real-time monitoring and analysis of the high-performance solar cells

Improving the Air Resistance of the Precursor Solution for Ambient-Air Coating of an Sn–Pb Perovskite Film with Superior Photovoltaic Performance

Owing to narrow band gap and low toxicity, tin–lead (Sn–Pb) hybrid perovskites have shown great potential in photovoltaic applications, and the highest power conversion efficiency (PCE) of Sn–Pb perovskite solar cells (PSCs) has recently reached 23.6%. However, it is still challenging to prepare Sn–Pb films in open-air condition due to the Sn2+ oxidation of the precursor solution under this condition. In this work, we report the stabilizing of the Sn–Pb perovskite precursor solution by using ionic liquid methylammonium acetate (MAAc) as the solvent, which enables the fabrication of Sn–Pb films in air. MAAc is found to coordinate with the Sn–Pb precursor via abundant hydrogen bonding, which stabilizes the colloids and protects the Sn2+ stability in the precursor solution in air. Therefore, the durability of the Sn–Pb precursor solution based on the MAAc solvent is greatly improved, which enables the fabrication of efficient PSCs and achieves a champion PCE of ∼16% with robust device stability. Moreover, due to the chemical interactions of MAAc with Sn–Pb perovskites, the Pb leakage is also suppressed in the MAAc-based Sn–Pb PSCs. This work demonstrates a feasible strategy for reliable fabrication of Sn–Pb PSCs, which could also be applied in many other optoelectronic devices

Improving the Air Resistance of the Precursor Solution for Ambient-Air Coating of an Sn–Pb Perovskite Film with Superior Photovoltaic Performance

Owing to narrow band gap and low toxicity, tin–lead (Sn–Pb) hybrid perovskites have shown great potential in photovoltaic applications, and the highest power conversion efficiency (PCE) of Sn–Pb perovskite solar cells (PSCs) has recently reached 23.6%. However, it is still challenging to prepare Sn–Pb films in open-air condition due to the Sn2+ oxidation of the precursor solution under this condition. In this work, we report the stabilizing of the Sn–Pb perovskite precursor solution by using ionic liquid methylammonium acetate (MAAc) as the solvent, which enables the fabrication of Sn–Pb films in air. MAAc is found to coordinate with the Sn–Pb precursor via abundant hydrogen bonding, which stabilizes the colloids and protects the Sn2+ stability in the precursor solution in air. Therefore, the durability of the Sn–Pb precursor solution based on the MAAc solvent is greatly improved, which enables the fabrication of efficient PSCs and achieves a champion PCE of ∼16% with robust device stability. Moreover, due to the chemical interactions of MAAc with Sn–Pb perovskites, the Pb leakage is also suppressed in the MAAc-based Sn–Pb PSCs. This work demonstrates a feasible strategy for reliable fabrication of Sn–Pb PSCs, which could also be applied in many other optoelectronic devices