Investigating the Impact of Shading Effect on the Characteristics of a Large-Scale Grid-Connected PV Power Plant in Northwest China

Northwest China is an ideal region for large-scale grid-connected PV system installation due to its abundant solar radiation and vast areas. For grid-connected PV systems in this region, one of the key issues is how to reduce the shading effect as much as possible to maximize their power generation. In this paper, a shading simulation model for PV modules is established and its reliability is verified under the standard testing condition (STC) in laboratory. Based on the investigation result of a 20 MWp grid-connected PV plant in northwest China, the typical shading phenomena are classified and analyzed individually, such as power distribution buildings shading and wire poles shading, plants and birds droppings shading, and front-row PV arrays shading. A series of experiments is also conducted on-site to evaluate and compare the impacts of different typical shading forms. Finally, some feasible solutions are proposed to avoid or reduce the shading effect of PV system during operation in such region

Oriented Graphene Nanoribbons Embedded in Hexagonal Boron Nitride Trenches

Graphene nanoribbons (GNRs) are ultra-narrow strips of graphene that have the potential to be used in high-performance graphene-based semiconductor electronics. However, controlled growth of GNRs on dielectric substrates remains a challenge. Here, we report the successful growth of GNRs directly on hexagonal boron nitride substrates with smooth edges and controllable widths using chemical vapour deposition. The approach is based on a type of template growth that allows for the in-plane epitaxy of mono-layered GNRs in nano-trenches on hexagonal boron nitride with edges following a zigzag direction. The embedded GNR channels show excellent electronic properties, even at room temperature. Such in-plane hetero-integration of GNRs, which is compatible with integrated circuit processing, creates a gapped channel with a width of a few benzene rings, enabling the development of digital integrated circuitry based on GNRs.Comment: 32 pages, 4 figures, Supplementary informatio

A STUDY ON THE EXTRACTION AND PURIFICATION PROCESS OF LILY POLYSACCHARIDE AND ITS ANTI-TUMOR EFFECT

The objective of this paper was to extract and purify lily polysaccharide and to study its anti-H22 hepatoma effect in mice. Orthogonal experimental method was used to analyze the factors influencing the extraction and purification of lily polysaccharide, and the anti-tumor effect of lily polysaccharide was studied by acting it on H22-bearing mice. The results showed that the size of influence of various factors on the extraction results of lily polysaccharide were extraction time, extraction times and extraction temperature in decreasing order. Lily polysaccharide can enhance the immune function of H22 tumor-bearing mice, and inhibit the growth of H22 tumor. The study concluded that the optimal conditions for the extraction and purification of lily polysaccharide should be extraction times of 3 times, an extraction time of 4 h each, and an extraction temperature of 60℃; lily polysaccharide has an anti-tumor effect

Classroom walkthroughs as an effective strategy for preschool improvement during the COVID-19 lockdowns: a Chinese model

Classroom walkthroughs are a widely used strategy for school improvement, varying over contexts and times. This study aims to explore the Chinese model of classroom walkthroughs in early childhood settings (ECS) during the COVID-19 lockdowns through a triangulated qualitative study. First, a group of ECS leaders (N = 15; Myear of teaching experience = 18.87, SD = 7.74, range = 6–33 years) and a group of teachers (N = 15; Myear of teaching experience = 8.40, SD = 3.96, range = 3–19 years) were interviewed in early 2022, and leaders’ observations notes were reviewed. The interview data were transcribed, recoded, and analyzed using an inductive approach, and the walkthrough documents were examined as a triangulation. Four themes and 13 subthemes emerged from the interview data: content, pedagogical skills, tasks, and challenges pertaining to classroom walk-throughs. Two major challenges against efficient classroom walkthroughs during the COVID-19 lockdowns were found: building community and feeding forward. Based on the results, a Chinese model of classroom walkthrough was proposed. Implications for quality improvement were also addressed

Antifungal effects of sisal leaf juice on Lasiodiplodia theobromae, the causal agent of mulberry root rot

This study was carried out to evaluate the antifungal activities of leaf juices (fresh juice, fermented juice, boiled juice and sterile juice) of nine sisal varieties on Lasiodiplodia theobromae, the causal agent of mulberry root rot. Results show that all the leaf juices could inhibit the mycelial growth in different degrees (the inhibitory rates ranged from 63.3 to 100%), due to different varieties and treatments. Among the nine varieties, the inhibition effects of hybrid 76416 and Agave americana were the best with absolute inhibition of all the leaf juice treatments against the mycelial growth, followed by Agave Amaniensis, Agave virdis, Agave angustifolia and Hybrid 11648. The inhibitory effect of some fresh juices would be cut down after being fermented, boiled and sterilized. The treated mycelia of L.theobromae were malformed, enlarged, broken and plasma leaked when observed under the microscope. Most of the leaf juices could inhibit the conidial germination absolutely, except A.amaniensis, H.11648 and A. angustifolia. The average germination rate of A. amaniensis, H.11648 and A. angustifolia was 72.4, 16.6 and 13%, respectively. The control efficiency of the fresh juice of H. 11648 against mulberry root rot in the field reached 73.1%.Key words: Sisal, leaf juice, anti-fungi, anti-fungal activities, mulberry root rot, Lasiodiplodia theobromae

miR-638 is a new biomarker for outcome prediction of non-small cell lung cancer patients receiving chemotherapy.

MicroRNAs (miRNAs), a class of small non-coding RNAs, mediate gene expression by either cleaving target mRNAs or inhibiting their translation. They have key roles in the tumorigenesis of several cancers, including non-small cell lung cancer (NSCLC). The aim of this study was to investigate the clinical significance of miR-638 in the evaluation of NSCLC patient prognosis in response to chemotherapy. First, we detected miR-638 expression levels in vitro in the culture supernatants of the NSCLC cell line SPC-A1 treated with cisplatin, as well as the apoptosis rates of SPC-A1. Second, serum miR-638 expression levels were detected in vivo by using nude mice xenograft models bearing SPC-A1 with and without cisplatin treatment. In the clinic, the serum miR-638 levels of 200 cases of NSCLC patients before and after chemotherapy were determined by quantitative real-time PCR, and the associations of clinicopathological features with miR-638 expression patterns after chemotherapy were analyzed. Our data helped in demonstrating that cisplatin induced apoptosis of the SPC-A1 cells in a dose- and time-dependent manner accompanied by increased miR-638 expression levels in the culture supernatants. In vivo data further revealed that cisplatin induced miR-638 upregulation in the serum derived from mice xenograft models, and in NSCLC patient sera, miR-638 expression patterns after chemotherapy significantly correlated with lymph node metastasis. Moreover, survival analyses revealed that patients who had increased miR-638 levels after chemotherapy showed significantly longer survival time than those who had decreased miR-638 levels. Our findings suggest that serum miR-638 levels are associated with the survival of NSCLC patients and may be considered a potential independent predictor for NSCLC prognosis