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The border area between south-eastern Yunnan, China and northern Vietnam is one of the regions with richest biological diversity including that of the fern genus Angiopteris (Marattiaceae). Based on the analysis of morphology and DNA sequences of multiple chloroplast regions (atpB, rbcL, rps4-trnS spacer and trnL-F spacer), we revised Angiopteris tonkinensis (Hayata) J.M.Camus and proposed a new combination Angiopteris tamdaoensis (Hayata) J.Y.Xiang & T.Wang, comb. nov., which was previously regarded as a synonym of A. tonkinensis. We found support for a monophyletic Angiopteris including Protomarattia. This discovery adds two new distribution sites of A. tonkinensis, one in China (Malipo, Yunnan) and one in Vietnam (Quan Ba, Ha Giang). We suggest A. tonkinensis should be categorised as Critically Endangered (CR) species according to the criteria of IUCN.

A new species of Malvaceae, Firmiana daweishanensis Gui L.Zhang & J.Y.Xiang from Southwest Yunnan, China, is described and illustrated here. It is similar to F. hainanensis in its bark and leaf shape, while its flower is quite similar to F. major. However, it is obviously different from both species by its character of proteranthus (flowering before the leaves), which is the critical character of Erythropsis distinguishing from Firmiana with hysteranthus (flowering after the leaves) character. Moreover, the androecium of F. daweishanensis is consisting of more than 30 sessile 2-celled anthers while that of the other two species only 10–15 anthers. The discovery of this species supports the idea that Firmiana and Erythropsis may be indistinct. This new species is only found in Daweishan area in Southeast Yunnan, China.

A new diploid species of marattioid ferns, Angiopteris sugongii Gui L. Zhang, J.Y. Xiang & Ting Wang (Marattiaceae), with ascending rhizomes, once pinnate to bipinnate laminae and marginal long sori, is identified and characterized from Southeast Yunnan, China. The distinctiveness between the new species and three relatives, A. itoi, A. bipinnata and A. sparsisora, are presented in detail, and a key to 11 species with once pinnate, or once pinnate to bipinnate laminae of Angiopteris in China is provided. Currently, there are three populations with 30 individuals in Daweishan National Nature Reserve and we suggest A. sugongii should be categorized as Critically Endangered (CR) species according to the criteria of IUCN. The discovery of this new species not only provides an important evidence for understanding the evolution of Angiopteris (sen. lat.), but also gives us a key insight into origin of species in the genus.

The molybdenum nitride films were fabricated by RF magnetron sputtering with various structural features by input power and gas flow ratio modulation. With Ar/N2 gas flow ratios from 10/10 to 18/2 and RF input powers from 150 to 300 W, the molybdenum nitride films evolved from significant crystalline to amorphous features. The coating deposited at an Ar/N2 ratio of 16/4 and an input power of 300 W showed an intensified Mo2N microstructure with preferred (111) orientation. In comparison, the crystalline phase of the coating was suppressed when an Ar/N2 ratio of 10/10 and an input power of 150 W were applied. The thickness, deposition rate and crystallinity of the molybdenum nitride increased with Ar/N2 ratio and power input. The crystalline and amorphous monolayers were alternately stacked to form multilayered films. The correlation between structural evolution and mechanical behavior, such as hardness, Young's modulus, and scratch characteristics of the molybdenum nitride multilayer films was discussed.

The rare and threatened fern Christensenia aesculifolia of South-east Asia is listed in China as a second-ranked plant for national protection and is also categorized as one of 62 plant species with extremely small populations by the Yunnan provincial government. Field investigations during 2014–2017 failed to relocate one previously known population, and revealed that the single known extant population of C. aesculifolia contains only 10 individual plants. The most urgent conservation requirement for this species is to conserve the threatened habitat of the remnant population. Further field surveys and research are also required for an improved understanding of the species’ status.

This paper reviews 31 groups in ferns and lycophytes hypothesized to show eastern Asian-North American disjunctions. Fourteen lineages have been supported by recent phylogenetic evidence: Lycopodium nikoense and Lycopodium sitchense; Isoetes asiatica and the clade of the North American species complex closely allied to I. maritima; Osmundastrum cinnamomeum; Osmunda claytoniana; the Adiantum pedatum complex; the Cryptogramma acrostichoides complex; Diplaziopsidaceae; Cystopteris chinensis and the Cystopteris bulbifera clade; Asplenium rhizophyllum and Asplenium ruprechtii; diploid Phegopteris; Onoclea sensibilis; the Polypodium appalachianum clade; and the Polypodium glycyrrhiza clade. Phylogenetic and/or cytological evidence did not support the biogeographic disjunctions in six cases: (1) Isoetes asiatica and I. truncata; (2) Botrychium ternatum; (3) Thelypteris beddomei and T. nipponicaThelypteris noveboracensis and T. nevadensis; (4) Thelypteris glanduligera and Thelypteris. japonicaT. simulata; (5) Woodwardia japonica and W. virginica; and (6) Woodwardia orientalis and Woodwardia fimbriata. Both vicariance and dispersal have been suggested to be the mechanisms for the formation of the disjunct pattern; and the Beringian region has been an active pathway for the migration of ferns and lycophytes between Asia and North America. Disjunctions of ferns and lycophytes reviewed here have been dated in the Tertiary, and are similar to the ages of eastern Asian-North American disjunctions in seed plants, supporting the close biogeographic co-diversification of ferns and seed plants. Future studies are needed to estimate divergence times and reconstruct biogeographic events in a broad phylogenetic framework, and to test the morphological stasis hypothesis in disjunct ferns and lycophytes.

A comparative study on mechanical properties and microstructure of 316L austenitic stainless steel between solution treated specimen and hot rolled specimen was conducted. After a specimen was subjected to solution treatment at 1050 °C for 6 min, its mechanical properties were determined through tensile and hardness tests. Based on the true stress vs true strain and engineering stress vs engineering strain flow curves, the work hardening rate has been explored. The results show that the solution treated specimen has an excellent combination of strength and elongation, and that this steel is easy to work-hardening during deformation. Optical microscope, scanning electron microscope, transmission electron microscope and X-ray diffraction examinations were conducted, these reveal that twins in 316L austenitic stainless steel can be divided into suspended twin and transgranular twin which have different formation mechanisms in growth, and that the deformation induced martensite nucleated and grown in the shear band intersections can be observed, and that the fracture surfaces are mainly composed of dimples and exhibit a tough fracture character.

The genus Bolbitis from Vietnam and Laos is revised; 14 species and two varieties are recognized. A new species, Bolbitis lanceolate S. K. Wu & J. Y. Xiang is described and illustrated. Bolbitis scandens W. M. Chu ex Ching et C. H. Wang and B. yunnanensis Ching ex Ching et C. H. Wang are two new records in both Vietnam and Laos. Bolbitis hekouensis Ching and B. latipinna Ching are treated as synonyms for the first time.

Leptochilus mengsongensis (Polypodiaceae), a new species of fern from Bulong Nature Reserve, Xishuangbanna, Yunnan, southwestern China, is described and illustrated. The main characters of morphological close relatives Leptochilus pedunculatus and Leptochilus axillaris were compared, results showed that it differs from L . axillaris mainly by its separate oblong-rhomboid acrostichoid patched sori, and densely set roots; meanwhile, it differs from L. pedunculatus mainly in its narrowly lanceolate fertile fronds, thinly leathery lamina and vague zigzag veins, and shorter stipe. Analysis of rbcL gene fragments of L. mengsongensis revealed that 20 of 663 sites differed from L. pedunculatus , thereby providing further evidence for its recognition as a distinct species.

Recognition rate is traditionally used as the main criterion for evaluating the performance of a recognition system. High recognition reliability with low misclassification rate is also a must for many applications. To handle the variability of the writing style of different individuals, this paper employs decision trees and WRB AdaBoost to design a classifier with high recognition reliability for recognizing Bangla handwritten numerals. Experiments on the numeral images obtained from real Bangladesh envelopes show that the proposed recognition method is capable of achieving high recognition reliability with acceptable recognition rate.

It is rather hard to achieve high recognition reliability using a single set of features and a single classifier for off-line handwritten numeral recognition systems. In this paper, we present a two-stage classifier for recognizing handwritten Bangla numerals. The first stage classifier is a decision tree based on ID3 algorithm, and the second one is a series of decision trees combined by Weight-Restricting-Based AdaBoost algorithm (WRB AdaBoost). Two sets of features are employed in the different stages. The first set is Open and Closed Cavity (OCC) features, and the other is a combination of OCC features and Ending and Crossing Point (ECP) features. Experiments on numeral images obtained from real Bangladesh envelopes show that the proposed recognition method is capable of achieving high recognition reliability.