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Laparoscopic box simulation training is widely recognized as an assessment tool to facilitate psychomotor skills especially for novice surgeons. However, current commercialized training modules including pegs, gauze, clips, pins etc. are generally costly and relatively inaccessible. We introduce a simple and pioneer surgical training drill, the Origami Box Folding Exercise (OBFE), based on the validated evaluating system of objective structured assessment of technical skills (OSATS) constructed with the scoring system of procedure-specific checklist (PSC) and global rating scale (GRS).

Atmospheric compositions and acid rain are closely related to atmospheric environment, weather, and climate change. In this study, the concentration levels and long-term trends of CO2, CH4, O3, PM2.5, PM10, and acid rain were presented at the Mt. Waliguan global baseline station in Qinghai, Shangdianzi and Lin'an regional background stations in the North China Plain (NCP) and the Yangtze River Delta region (YRD) of China based on the data observed until 2018. Significant increasing trends of CO2were found at all of these stations. At Mt. Waliguan, the concentration levels and growth rate were consistent with the average values in the Northern Hemisphere (NH) and those observed at the Mauna Loa station in Hawaii. The CH4also showed a upward tendency similar to that observed in NH. Compared with the observations at Mt. Waliguan global baseline station, the CO2and CH4mole fractions were higher at Shangdianzi and Lin'an regional background stations, indicating the important contributions of anthropogenic activities to the regional background level of CO2and CH4. The annual averaged surface ozone showed increasing trends at Mt. Waliguan and Shangdianzi stations, whereas no clear trend was found at Lin'an station. Similar variations in the patterns of aerosol concentrations at Shangdianzi and Lin'an were found according to the PM2.5or PM10observations. Overall, the aerosol concentrations at both stations shown declining trends since the observations. However, two periods of high particle concentrations occurred in 2006–2007 and 2013–2014. The annual mean aerosol concentrations have continuously decreased after 2013–2014, indicating the effectiveness of pollution control in the NCP and YRD, especially since the implementation of the ‘Action Plan for Prevention and Control of Air Pollution’ in September 2013. Comparative analysis of aerosol with acid rain showed that the period with high concentrations of aerosols in the early years was consistent with that of severe acid rain pollution, suggesting that both aerosol pollution and severe acid rain are closely related to coal combustion emissions in China. As a result of the control of coal combustion emissions for acid and SO2, NOxemissions have contributed more substantially to aerosols due to the rapid growth of vehicle ownership. A comparison of the trends of aerosols with the maximum daily 8-h average of surface ozone (MDA8) at Shangdianzi and Lin'an stations revealed the complicated relationship between aerosol reduction and ozone production, i.e., together with the continuous improvement of particulate pollution in the NCP and YRD, the MDA8 at both stations showed a decreasing trend at first but subsequently increased after 2014 with aerosols remaining reduced. Such different variation patterns of the MDA8 with PM2.5(or PM10) indicated the high challenge of synergic control of aerosol and ozone pollution in China.

We have realized the 4‐side micro (0.9x/0.9x/0.9x/0.9x mm) border 8k4k 120Hz LCD with Oxide thin‐film transistor (TFT) for the first time. Most of narrow border prototypes in past was 3‐side with 2‐COF process for both gate and data driving, but now, we have been developing the most cost effective 4‐side micro border LCD with only data COF. As core technology, 1G1D pixel driving and GDCIAA (Gate Driver Circuit in Active Area) with oxide TFT backplane are incorporated without any additional investment of module assembly. In practical point of view, this technology can render about 70% reduction of D‐IC cost and additional value up as a form factor of premium product compare to a‐Si TFT based LCD. Moreover, simplified 1G1D bus line structure can contribute to production yield improvement. In this report, we present the most valuable 8k4k LCD product with the latest AUOs Oxide TFT backplane technology.

In this letter, we successfully explored a cascade Pd/Cu-catalyzed intermolecular C(sp3)–H arylation of amides and intramolecular C–N coupling reaction. This method provides a one-pot strategy to synthesize 3,4-2H-quinolinone with good regioselectivity of C–H arylation and C–N coupling from C–I and C–X bonds from readily available starting materials.

TiB2/7055 composite was synthesized by a new melt direct reaction from 7055-(Al-3B)-Ti system with ultrasound. The phase composition and the microstructures of the as-prepared samples were investigated by XRD, SEM and EDS. The result shows that no Al3Ti phase is in existence. With the assistance of ultrasound, grains are significant refined. Moreover, the wettability between matrix and particles is improved. The shapes of TiB2 particles are mainly hexagonal or near-spherical, and the size is about 500nm. TiB2 particles are with uniform distribution. Compared with 7055Al matrix alloy, the tensile strength of the composite reaches 303MPa, increased by 10.2%. However, the elongation is 7.3%, decreased by 4.8%.

The effect of coal based polyaniline compounds (CPANI) added into epoxy coating on the corrosion of mild steel in solutions of 5% sodium chloride (NaCl) has been investigated in relation to the proportion of the CPANI from 0% to 40% by various monitoring corrosion techniques. Interface morphology was studied by SEM. Results obtained revealed that the CPANI compound has good inhibitive corrosion for mild steel.

A new bis(ether-carboxylic acid), 9,9-bis[4-(4-carboxyphenoxy)phenyl]fluorene (3), was synthesized from the nucleophilic fluorodisplacement of p-fluorobenzonitrile with the dipotassium bisphenolate of 9,9-bis(4-hydroxyphenyl)fluorene, followed by alkaline hydrolysis of the intermediate bis(ether nitrile). A novel series of aromatic polyamides containing ether and bulky fluorenylidene groups were prepared by the direct polycondensation of the diacid 3 with various aromatic diamines in N-methyl-2-pyrrolidone (NMP) solution containing dissolved CaCl2 using triphenyl phosphite and pyridine as condensing agents. The obtained polyamides have inherent viscosities in the range of 0.50–1.75 dL/g. All the polymers are readily soluble in a variety of organic solvents, such as NMP, N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), and m-cresol, and afford transparent, flexible, and tough films by solvent casting. These polyamides have glass transition temperatures ranging from 200 to 303°C and show no significant weight loss up to 450°C, with 10% weight loss being recorded above 511°C in nitrogen or air.

A new bis(ether-carboxylic acid), 9,9-bis[4-(4-carboxyphenoxy)phenyl]fluorene (3), was synthesized from the nucleophilic fluorodisplacement of p-fluorobenzonitrile with the dipotassium bisphenolate of 9,9-bis(4-hydroxyphenyl)fluorene, followed by alkaline hydrolysis of the intermediate bis(ether nitrile). A novel series of aromatic polyamides containing ether and bulky fluorenylidene groups were prepared by the direct polycondensation of the diacid 3 with various aromatic diamines in N-methyl-2-pyrrolidone (NMP) solution containing dissolved CaCl2 using triphenyl phosphite and pyridine as condensing agents. The obtained polyamides have inherent viscosities in the range of 0.50–1.75 dL/g. All the polymers are readily soluble in a variety of organic solvents, such as NMP, N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), and m-cresol, and afford transparent, flexible, and tough films by solvent casting. These polyamides have glass transition temperatures ranging from 200 to 303°C and show no significant weight loss up to 450°C, with 10% weight loss being recorded above 511°C in nitrogen or air.

Over the past decade, time-domain astronomy in optical bands has developed rapidly with the operations of some wide-field survey facilities. However, most of these surveys are conducted with only a single band, and simultaneous color information is usually unavailable for the objects monitored during the survey. Here we present introductions to the system of Tsinghua University-Ma Huateng Telescopes for Survey (TMTS), which consists of an array of four optical telescopes installed on a single equatorial mount. Such a system is designed to get multiband photometry simultaneously for stars and transients discovered during the survey. The optics of each telescope is a modified Hamilton-Newtonian system, covering the wavelengths from 400 to 900 nm, with a field of view (FoV) of about 4.5 deg2and a plate scale of 1.?86 pixel?1when combining with a 4K× 4KQHY4040 CMOS detector. The TMTS system can have a FoV of about 9 deg2when monitoring the sky with two bands (i.e., SDSS gand rfilters) at the same time, and a maximum FoV of ?18 deg2when four telescopes monitor different sky areas in monochromatic filter mode. For an exposure time of 60 s, the average 3?detection limit of the TMTS system can reach at ?19.4 mag in Luminous filter and at ?18.7 mag in SDSS rfilter. The preliminary discovery obtained during the first few months' survey is briefly discussed. As this telescope array is located at the Xinglong Observatory of NAOC, it can have an excellent synergy with the spectroscopic survey by the LAMOST (with a FoV of about 20 deg2) at the same site, which will benefit the studies of stellar and binary physics besides the transient sciences.

The photoacoustic effect is one of the most sensitive methods for measurements of the low optical absorption in glasses and crystals. Previously, a new photoacoustic technique has been developed, where a cw laser modulated at the acoustic resonant frequency of the sample generates an acoustic signal amplified by the quality factor of the resonance. With typical quality factors in the order of 105, this technique is several orders of magnitude more sensitive than conventional pulsed‐laser techniques. However, previous applications using noncontact capactive transducers required precise postitioning of the sample, transducers, and seperate sample supports. Recently, this difficulty has been reduced through the use of 9‐μm‐thick piezoelectric (PVDF) film transducers. By supporting the sample at the corners between the film transducers, the need for separate supports is eliminated, with only a small reduction in the quality factor of the resonance. In addition, a large improvement in the signal‐to‐noise ratio is observed. Recent measurements on large single crystals of calcium floride and quartz will be discussed. [Work supported by NSF Grant No. DMR‐9000549 and by the Office of Naval Research.]