1,725,646 research outputs found
Li Peng: Eine Biographie
Full text linkLi Peng, der am 24.11.87 vom Standigen AusschuB des Nationalen Volkskongresses (NVK) zum amtierenden Ministerprasidenten ernannt wurde und der damit die Nachfolge von Zhao Ziyang in diesem Amt antrat, ist der vierte Ministerprasident der Volksrepublik China nach Zhou Enlai, Hua Guofeng und eben Zhao Ziyang. Der wahrscheinlich im Marz 1988 tagende VII. NVK wird diese Ernennung voraussichtlich bestatigen. Li Peng war seit Juni 1983 stellvertretender Ministerprasident
Lesteva concava Cheng & Li & Peng 2019, new species
No full textLesteva (s. str.) concava, Cheng, Li & Peng, new species (Figs 2B, 3 G–H, 5D–F, 24) Type material (64 exs). Holotype: CHINA: ♂: ‘ China: Zhejiang Prov., Lin’an City (临安市), Mt. Qingliang (清 凉峰), 1050–1080 m, 8–10.v.2005, Zhu & Li leg. ’ / HOLOTYPE (red), L. concava sp. nov., det. Cheng, Li & Peng, 2019, SNUC. Paratypes: CHINA: 17 ♂♂, 34 ♀♀: same label data as holotype / PARATYPE (yellow), L. concava sp. nov., det. Cheng, Li & Peng, 2019, SNUC; 1 ♀: ‘ China: Anhui Prov., Anqing City (安庆市), Qianshan County (潜山县), Mt. Tainzhu (天柱山), 1150–1250 m, 25.iv.2005, Hu & Tang leg. ’ / PARATYPE (yellow), L. concava sp. nov., det. Cheng, Li & Peng, 2019, SNUC; 1 ♀: ‘ China: Anhui Prov., Chizhou City (池州市), Shitai County (石台县), Guniujiang N. R. (牯牛降自然保护区), alt. 300 m, 27.iv.2005, Hu & Tang leg. ’ / PARATYPE (yellow), L. concava sp. nov., det. Cheng, Li & Peng, 2019, SNUC; 1 ♀: ‘ China: Zhejiang Prov., Hangzhou City (杭州 市), Anji County (安吉 县), Mt. Longwang (龙王 山), 300–500 m, 24.iv.2004, Jing-Wen Zhu leg. ’ / PARATYPE (yellow), L. concava sp. nov., det. Cheng, Li & Peng, 2019, SNUC; 2 ♀♀: ‘ China: Zhejiang Prov., Hangzhou City (杭州市), Anji County (安吉县), Mt. Longwang (龙王山), 250–550 m, 24.iv.2006, Jin-Wen Li leg. ’ / PARATYPE (yellow), L. concava sp. nov., det. Cheng, Li & Peng, 2019, SNUC; 2 ♀♀: ‘ China: Zhejiang Prov., Hangzhou City (杭州市), Anji County (安吉县), Mt. Longwang (龙王山), 1050–1200 m, 15.v.2013, Chen & Pan leg. ’ / PARATYPE (yellow), L. concava sp. nov., det. Cheng, Li & Peng, 2019, SNUC; 1 ♀: ‘ China: Zhejiang Prov., Lin’an City (临安市), Mt. Tianmu (天目山), 800–1150 m, 2.v.2001, Jiao-Yao Hu leg. ’ / PARATYPE (yellow), L. concava sp. nov., det. Cheng, Li & Peng, 2019, SNUC; 1 ♀: ‘ China: Zhejiang Prov., Lin’an City (临安市), Mt. Tianmu, (天目山), 800–1150 m, 31.v.2006, Hu & Tang leg. ’ / PARATYPE (yellow), L. concava sp. nov., det. Cheng, Li & Peng, 2019, SNUC; 1 ♂: ‘ China: Zhejiang Prov., Lin’an City (临安市), Mt. Tianmu, (天目山), 830–900 m, 31.v.2010, Wang, Xu & Zhu leg. ’ / PARATYPE (yellow), L. concava sp. nov., det. Cheng, Li & Peng, 2019, SNUC; 1 ♂, 1 ♀: ‘ China: Zhejiang Prov., Quzhou City (衢州市), Jingning County (景宁 县), Baiyunlinqu (白云林区), 1100–1270 m, 07.v.2012, Jian-Qing Zhu leg. ’ / PARATYPE (yellow), L. concava sp. nov., det. Cheng, Li & Peng, 2019, SNUC. Description. Measurements (in mm) and ratios: BL 3.04–3.29; FL 2.36–2.48; HL 0.47–0.50; HW 0.59–0.62; PL 0.56–0.59; PW 0.65–0.68; EL 1.27–1.33; EW 1.18–1.21; HL/HW 0.75–0.79; PL/PW 0.86–0.90; EL/EW 1.07–1.11; HW/PW 0.90–0.95; PL/EL 0.44–0.46; AnL 1.39–1.42; AeL 0.46–0.50. Habitus as in Fig. 2B. Reddish brown, head usually darker, blackish brown; mouthparts fuscous brown; antennae yellowish brown; elytra with small subtriangular yellow maculae near middle; legs reddish brown, except of paler apex of tibiae and tarsi. Pubescence of body pale, evident and recumbent. Head subtriangular, coarsely and sparsely punctate, widest across eyes; eyes prominent, 1.86 times longer than temples; ocelli distinct, distance between ocelli 1.75 times as long as distance between ocellus and posterior margin of eye. Antennae elongate, relative lengths of the antennomeres I–XI: 1.54: 1: 1: 1: 1: 1: 1.15: 1.15: 1.15: 1.15: 1.77. Pronotum subcordate, moderately convex, widest near anterior third; lateral margins arcuate at anterior twothirds and nearly straight at posterior third; punctation and pubescence as that on head; disc with shallow U-shaped depression. Scutellum subtriangular, surface with fine punctation and pubescence. Elytra subtrapezoidal, gradually dilated posteriorly, posterior angles broadly rounded; punctation and pubescence distinctly finer and sparser than those on pronotum. Abdomen broad, widest at segment IV (first visible abdominal segment), then distinctly narrowed posteriorly. Tergites with dense, fine punctation and decumbent pubescence, devoid of microsculpture; middle of the tergites IV and V with one pair of tomentose patches, but patches on tergite V smaller and less transverse. Male. Apical margin of the tergite VIII (Fig. 3G) broadly concave; sternite VIII (Fig. 3H) transverse, apical margin weakly concave; median lobe of the aedeagus (Figs 5 D–F) slightly longer than parameres; parameres somewhat asymmetrical, each slightly narrowed in anterior half, with three long apical setae; internal sac without sclerotized spines and without distinct dark membranous structures. Female. Abdominal sternite VIII without concavity apically. In other morphological characters similar with males. Comparative notes. Lesteva concava is closest to L. cooteri Rougemont in sharing similar body size, and punctation and pubescence of the head and pronotum. These two species can be readily separated by the different coloration of the body, and especially the narrower aedeagus with longer median lobe and narrower and longer parameres in L. concava. For illustrations of L. cooteri see Figs 6A, 8 A–B, 9A–C and Rougemont (2000: figs 1, 13). Distribution and nature history. China: Anhui, Zhejiang (Fig. 24). Some specimens were sifted from leaf litter near a stream in mixed deciduous forests at Mt. Tianzhu, Anhui. Etymology. The new specific epithet refers to the broadly concave apical margin of the male tergite VIII.Published as part of Cheng, Zhi-Fei, Li, Li-Zhen & Peng, Zhong, 2019, New species and new records of Lesteva Latreille, 1797 (Coleoptera Staphylinidae: Omaliinae) from China, pp. 1-39 in Zootaxa 4560 (1) on pages 5-9, DOI: 10.11646/zootaxa.4560.1.1, http://zenodo.org/record/262725
Stimulated Brillouin scattering in integrated nano-scale waveguides and its applications using Aluminium Nitride
No full textIn this work, the author theoretically and numerically studies the stimulated Brillouin scattering (SBS) in integrated nano-photonic waveguides. The author first reviews the progress in the field of SBS, including the discoveries of SBS, current progresses in the field of SBS and its applications. Then the author reviews and compares two mechanisms for the SBS in nano-scale waveguides. One of them describes the SBS in waveguides via optical forces induced by electrostriction and optical radiation on the waveguide boundary. The other one is understood from the acoustic wave’s modulation to the optical mode. The modulation is realized via photoelasticity and moving boundary. Both methods are validated by matching the simulation results from author’s models with reported results. In addition, the author analyses and compares the differences and links between these two mechanisms mathematically. To analyse the strength of the SBS (indicated by a parameter called the Brillouin gain), the quality factor (Q factor) of the mechanical mode is of great importance. This is because in order to generate sufficient SBS, it would require the simultaneous confinement of both optical mode and acoustic mode. While optical mode, in most designs, are well confined. The acoustic mode, on the other hand is not well confined and leaky. Q factor, reflecting how much energy is lost, is a crucial parameter in calculating the final SBS gain coefficient. The mechanical Q factor is decided by various resources. Among all the loss factors, anchor loss is believed to be the main loss in high frequency resonators. One method to obtain accurate Q factor is via perfectly matched layer (PML). However. one has to choose proper parameters of the PML to optimize its performance. Based on the mathematical analysis of PML and the well-researched beam resonator structure, the author proposes a novel method for setting up a well-behaved PML. The results show that the choice of a parameter defined as PML scale factor α via COMSOL is the key to obtain the accurate Q factor. This method is validated by matching the simulation results of substrate thickness’s impact on Q factor with the theoretical prediction for a beam resonator. Subsequently, the author proposes a III-V novel material Aluminium Nitride (AlN) as a candidate for the SBS application in visible wavelength range for its wide transparent window and unique piezoelectricity. A full-vectorial model for calculating SBS gain is first validated. Then the author studies the forward and backward SBS process in a partially suspended AlN waveguide for TE (transverse electric) mode and TM (transverse magnetic) mode, separately. The author obtains the value of Brillouin gain of 1311 W−1m−1 when Q factor is dominated by anchor loss. Apart from extending the SBS application into shorter wavelength range, another issue hindering the development of SBS is that most platforms requires partially or fully suspension of the core waveguide to stop phonon leakage into the substrate. The author proposes a silicon-AlN-sapphire platform for realizing large SBS gain without suspending the waveguide. The genetic algorithm (GA) is leveraged to optimize the waveguide structure. A simple structure is obtained with SBS gain of 2462 W−1m−1, which is 8 times larger than the recently reported result in unsuspended silicon waveguide. This platform can enable Brillouin-related phenomena in centimetre-scale waveguide and pave the way toward large-area unreleased opto-mechanics on silicon. Finally, the author presents fabrication results for realizing aforementioned platforms. A highly c-axis oriented AlN thin film is sputtering deposited on the top of silica via sputtering machine. The primary etching test proves that normal KOH- or TMAH based developer will react with AlN. These information will be helpful for the future work of realizing on-chip SBS laser. Conclusions and future perspectives for the development of on-chip SBS applications are presented in the final chapter
Method for optimising the performance of PML in anchor-loss limited model via COMSOL
No full textPerfectly matched layer has been used for solving anchor-loss limited quality factor in the Micro electromechanical systems. However, setting up a well-behaved perfectly matched layer requires users to change the parameters of a perfectly matched layer to give correct results, while the current existing methods for choosing the right parameters are vague and lack theoretical support. Based on the mathematical theory of perfectly matched layer and simulation results of a beam structure's quality factor, this paper proposes a method for choosing the parameter to optimise the performance of perfectly matched layer in COMSOL. The accuracy of the proposed method is proved by matching the effect of substrate height on beam's quality factor with theory prediction. The author also studies the effect of beam height and beam width on the quality factor of the beam. The results demonstrate that simulated quality factors are in agreement with analytical values when the ratio of height over length is small but will show great divergence when height equals the length. This trend can be observed for the beam width as well. Especially for larger ratio of beam width over beam length, instead of decreasing monotonously as analytical equitation would expect, the simulated quality factor will converge into a stable value of 1700, which matches the result of two-dimensional model for the same beam structure. This means that a three-dimensional model has to be used for estimating the quality factor of a beam structure
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A new species of Hemiphyllodactylus Bleeker, 1860 (Squamata: Gekkonidae) from western Yunnan, China
No full textGuo, Weibo, Zhou, Kaiya, Yan, Jie, Li, Peng (2015): A new species of Hemiphyllodactylus Bleeker, 1860 (Squamata: Gekkonidae) from western Yunnan, China. Zootaxa 3974 (3): 377-390, DOI: 10.11646/zootaxa.3974.3.
Lesteva obesa Cheng & Li & Peng 2019, new species
No full textLesteva (s. str.) obesa Cheng, Li & Peng, new species (Figs 16A, 18 A–B, 19A–C, 34) Type material (1 ex.). Holotype: ♂: ‘ China: Chongqing City (重庆市), Chengkou County (城口县), Mt East Dabashan (东大巴山), upper Huang’an Gou (黄安沟), N31.51.785, E109.09.459, alt. 2039 m, 22–23.iv.2008, Hao Huang & Wang Xu leg. ’ / HOLOTYPE (red), L. obesa sp. nov., det. Cheng, Li & Peng, 2019, SNUC. Description. Measurements (in mm) and ratios: BL 2.50; FL 1.72; HL 0.41; HW 0.53; PL 0.53; PW 0.60; EL 1.13; EW 1.29; HL/HW 0.77; PL/PW 0.88; EL/EW 0.88; PL/EL 0.82; AnL 1.38; AeL 0.50. Habitus as in Fig. 16A. Reddish brown, head usually darker, blackish brown; mouthparts and antennae fuscous brown; elytra reddish brown, but lateral and posterior margin paler; elytra with obscure oblique dark red maculae, extending from shoulders toward suture in middle of the elytra; femora fuscous brown, tibiae paler, tarsi yellowish brown. Pubescence of body pale, evident and recumbent. Head subtriangular, with very coarse and dense punctation, widest across eyes; eyes moderately large and prominent, twice as long as temples; ocelli distinct, distance between ocelli 1.22 times as long as distance between ocellus and inner margin of the compound eye. Antennae elongate, relative lengths of the antennomeres I–XI: 1.54: 1: 1: 1.08: 1.08: 1.08: 1: 1: 1: 1: 1.77. Pronotum subcordate, distinctly convex, moderately transverse widest near anterior third; lateral margins arcuate at anterior two-thirds and nearly straight at posterior third; punctation and pubescence coarser and sparser than those on head; disc with shallow U-shaped impression. Scutellum subtriangular, with fine and sparse punctation and pubescence. Elytra subtrapezoidal, gradually dilated posteriorly, posterior angles broadly rounded; punctation and pubescence distinctly finer and sparser than those on pronotum. Abdomen broad, widest at segment IV (first visible abdominal segment) then narrowed posteriorly; surface of tergites somewhat closely covered with very fine punctation and pubescence, without microsculpture; tergite V with a pair of large and moderately transverse tomentose patches. Male. Apical margin of the tergite VIII (Fig. 18A) weakly concave; sternite VIII (Fig. 18B) transverse, apical margin strongly concave. Median lobe of the aedeagus (Figs 19 A–C) significantly wide basally, narrowing toward apex, slightly longer than parameres; parameres somewhat asymmetrical, with four short apical setae. Female. Unknown. Comparative notes. Based on the coloration of the body, punctation and pubescence of the head and pronotum and shape of the median lobe of the aedeagus, the new species is most similar to L. qinlingmontis Rougemont (Shaanxi: Qinling Shan), from which it can be distinguished by a shallow U-shaped impression on the disc of the pronotum, shapes of the elytra and slender parameres. For illustrations of L. qinlingmontis see Rougemont. (2017: 3, 3a). Distribution and natural history. The type locality is situated in Mt. East Dabashan to the Chengkou County, northern Chongqing, near Shaanxi Province (Fig. 34). The specimen was sifted from leaf litter near a stream in mixed deciduous forests at an altitude of 2039 m. Etymology. The specific epithet ‘ obesa ’ mean ‘obese’, referring to the morphology of the body in the male of the new species.Published as part of Cheng, Zhi-Fei, Li, Li-Zhen & Peng, Zhong, 2019, New species and new records of Lesteva Latreille, 1797 (Coleoptera Staphylinidae: Omaliinae) from China, pp. 1-39 in Zootaxa 4560 (1) on pages 19-20, DOI: 10.11646/zootaxa.4560.1.1, http://zenodo.org/record/262725
Hygrodromicus carbonarius Cheng, Li & Peng 2021, sp. n.
No full textHygrodromicus carbonarius Cheng, Li & Peng, sp. n. (Figs 1–2, 7, 8B) Type material (3 ♂♂, 6 ♀♀). Holotype: ♂, ‘ China: Xizang, Linzhi City, Gongbujiangda County [工布江ffi县], near Gaduogang Village [ḋľÑ村], 29°53′60″N, 93°14′22″E, alt. 3620 m, 18.vii.2018, Cheng, Peng & Shen leg. / HOLOTYPE ♂, H. carbonarius sp. n., det. Cheng, Li & Peng, 2021, SNUC’ (SNUC). Paratypes: 1 ♂, 6 ♀♀, same data as the holotype (SNUC); 1 ♂, ‘ China: Yunnan Prov., Fugong, Lishadi Town, 8.5 km up Shibali, riverside, 27.18408°N, 98.71882°E, 3095 m, 2005.VIII.8 day, Liang H.B., Zhang J.F. California Academy & IOZ., Chinese. Acad. Sci. ’ (SNUC); All paratypes with label: ‘ PARATYPE ♂ [or ♀], H. carbonarius sp. n., det. Cheng, Li & Peng, 2021, SNUC’. Description. Measurements (in mm) and ratios: BL 4.45–5.95; FL 2.84‒3.56; HL 0.61–0.89; HW 0.83–0.95; PL 0.78–1.17; PWb 0.83–1.00; PWm 0.83‒1.17; EL 1.28–1.72; EW 1.45‒2.06; AnL 2.71‒3.41; AeL 0.93‒0.99; HL/HW 0.69–0.94; PL/PWm 0.76‒0.84; EL/EW 0.79–0.90. Body (Fig. 1A) broad, black, antennae paler, basal portions of femora, apical portions of tibiae and tarsi reddishbrown. Head (Fig. 1B) subtriangular and transverse, broadest at level of eyes; vertex strongly transverse, with deep Ushaped impression between eyes; frons between supra-anternnal tubercles slightly impressed; clypeus short and narrow, weakly convex; eyes moderately prominent, about 1.50 times as long as temples (holotype); ocelli indistinct, distance between ocelli 1.1 times as long as distance between ocellus and posterior margin of eye (holotype). Vertex and frons covered with coarse and dense punctures, and reticular microsculpture. Pubescence on head long, dense and decumbent in anterior portion. Labrum (Fig. 1D) subrectangular, with slightly concaved anterior margin. Mandibles (Figs 1E–F) subtriangular, each with broad base, and curved distal tooth; right mandible armed with a small distinct subtriangular tooth on inner margin near middle; prostheca with short and dense pubescence from base to above middle of mandible. Maxilla (Fig. 1G) with smooth subtriangular stipes, subrectangular palpifer with long pubescence on external margin, elongate galea with short pubescence, and slender lacinia with dense pubescence and long teeth. Maxillary palpi composed of minute and elongate palpomere 1, slightly curved palpomere 2, broadened palpomere 3, and short subcylindrical palpomere 4. Labium (Fig. 1H) elongate, with flattened prementum divided by longitudinal groove anteriorly. Labial palpi long, palpomere 1 moderately large and elongate; palpomere 2 robust, broadened apically; palpomere 3 slender, distinctly narrower than palpomere 2. Antennae (Fig 1C) with long antennomeres; length × width (in mm) of antennomeres 1–11 (holotype): 0.26 × 0.13: 0.15 × 0.11: 0.19 × 0.11: 0.21 × 0.11: 0.22 × 0.11: 0.22 × 0.11: 0.25 × 0.11: 0.25 × 0.11: 0.25 × 0.11: 0.22 × 0.11: 0.34 × 0.11. Pronotum subtrapezoidal, broadest near anterior fourth; anterior margin widely rounded, lateral margins in anterior 2/3 rounded and nearly straight at posterior third, basal margin straight; hind angles obtuse; disc distinctly convex, with indistinct impression, stretching from middle to base. Punctures of disc finer and denser than those of head; pubescence moderately long, dense and decumbent in posterior portion; microsculpture distinct and evenly distributed. Scutellum triangular, covered with several punctures and pubescence, and distinct microsculpture. Elytra subtrapezoidal, short, distinctly wider than long, gradually dilated posteriorly, posterior angles broadly rounded; punctures and pubescence similar to those of pronotum; microsculpture absent. Hind wings brachypterous, but not completely reduced. Abdomen distinctly transverse, widest at segment IV, evenly narrowing posteriorly. Tergites with fine punctures and microsculpture, and short decumbent pubescence, denser on apical tergites; tergites IV–V with a pair of tomentose spots in middle, spots on tergite V smaller and less transverse. Male. Apical margin of abdominal tergite VIII (Fig. 1I) somewhat truncated, indistinctly emarginated; apical margin of abdominal sternite VIII (Fig. 1J) broadly emarginated. Aedeagus (Figs 2A–C) elongate, median lobe slightly emarginated in lateral margins near anterior third; parameres slightly asymmetrical, slender, significantly exceeding apex of median lobe, each bearing four apical setae; internal sac with submedian elongate membranous structures and long flagellum between them. Female. Apical margin of abdominal sternite VIII without concavity apically. Comparative notes. Based on the general shape of the forebody, coloration, shapes of maxillary and labial palpi, the presence of U-shaped impression between eyes, and shapes of apical margins of male tergite and sternite VIII, H. carbonarius sp. n. is most similar to H. danlangi sp. n., but differs by the wider pronotum, the presence of additional small tooth in inner margins of mandible, less concaved apical margin of labrum, and details of the internal and external morphology of the aedeagus. Distribution. Southwestern China: Xizang, Yunnan (Fig. 7). Bionomics. The species inhabits wet mosses or mixed leaf litter on banks of small streams with very cold water (Fig. 8B). Specimens were collected at high elevations more than 3000 m a.s.l. in Xizang in July and in Yunnan in August. Etymology. The specific epithet ‘ carbonarius ’ means ‘carbon’, referring to the coloration of a new species, black as carbon.Published as part of Cheng, Zhi-Fei, Pan, Zhao-Hui, Li, Li-Zhen & Peng, Zhong, 2021, Three new species of Hygrodromicus Tronquet, 1981 (Coleoptera: Staphylinidae Omaliinae: Anthophagini) from China, pp. 138-148 in Zootaxa 4963 (1) on pages 139-142, DOI: 10.11646/zootaxa.4963.1.6, http://zenodo.org/record/471997
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