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1

Three-dimensional biomechanical modeling and simulation of trephine cutting cornea for keratoplasty

Su P., Lu D., Deng S., Zhang L., Hao Y., Yang Y.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 2

23--33

EN

Trephination is one of the basic operations of keratoplasty, and the biomechanical mechanism of the operation can be revealed based on three-dimensional modeling and simulation of trephine cutting cornea. Methods: Based on the analysis of the physical and biomechanical characteristics of corneal trephination, a three-dimensional numerical model of corneal trephination is built, where the cornea can be simplified to two layers structure including stroma and epithelium, and the trephine cuts the cornea under the vertical motion load and the rotational motion load. A three-dimensional failure criterion of corneal material is proposed based on the yield strength theory. On this basis, trephination simulation is carried out, and the units of corneal material are removed from the model when they meet the defined failure criterion. Results: Under the given parameters including the velocity, the angle and the angular velocity, the trephine force curves, include the linear cutting force and the rotary cutting force are obtained, and show the change of the forces with displacement during the process of trephination simulation. The maps of the equivalent stress show the destruction and deformation of the cornea. Then, the experiment of robotic trephination is carried out under the same parameters and the effectiveness of the simulation is evaluated. Conclusions: Based on mechanics theory and finite element method, the process of trephine cutting cornea has been reproduced, and the interaction mechanism is revealed, which lays the foundation for the development of real-time simulation and virtual system of the corneal surgery.

2

Synergism of octane phenol polyoxyethylene-10 and oleic acid in apatite flotation

Cheng R., Li C., Liu X., Deng S.

Physicochemical Problems of Mineral Processing

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2017

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Vol. 53, iss. 2

1214--1227

EN

The addition of octane phenol polyoxyethylene-10 (OP-10) to oleic acid via a reagent-combination technology was carried out and it was shown that OP-10 exhibited synergistic effects in the flotation performance of oleic acid. Single-mineral flotation tests, zeta-potential measurements, total-organic-carbon determination, and scale-up of continuous tests using raw ore were also carried out. Single-mineral flotation tests showed that OP-10 exhibited virtually no collecting performance for apatite, but it improved the flotation performance of oleic acid following its addition to oleic acid in small amounts at low temperature. Zeta-potential measurements and total-organic-carbon determination results indicated that the addition of 2.5% OP-10 to oleic acid increased the absolute value of the apatite surface potential and improved adsorption of oleic acid on the apatite surface at low temperature. A scale-up of the continuous test showed that application of OP-10 with industrial fatty acids led to good synergistic effects and contributed to effective separation of phosphate ore.

3

Key preprocessing technology and its application for CBM AVO analysis

Liu Z., Si G., Chen X., Wang Q., Deng S.

Acta Geophysica

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2017

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Vol. 65, no. 5

1069--1079

EN

The hazards of amplitude versus offset (AVO) technique mostly applied in seismic explorations for predicting coalbed methane (CBM) content mainly derive from multi-stage amplitude modifications during seismic signal preprocessing. The modifications are undoubtedly necessitated by improving high signal-to-noise ratio (SNR) and high resolution, and achieve high fidelity to some extent; and nevertheless lead to an unfavorable possibility to implement CBM AVO analysis. Similar to sand-stone reservoir with gas, AVO analysis preprocessing for CBM reservoir strictly abides by a relative amplitude preserved (RAP) principle and particularly emphasizes on preserving the evanescent class IV AVO anomaly. As for those indispensable dealings with linear noise attenuations, near-surface variety compensations and time/depth spatial imaging, the key technologies adapted to CBM AVO preprocessing should use radial trace (RT) filter, refined surface-consistent amplitude compensation (SCAC), and RAP Kirchhoff prestack time migration (PSTM). The theoretical analysis and one real 3D example in this paper demonstrate that three key technologies compliant to RAP principle in CBM AVO preprocessing can preserve the class IV AVO anomaly and benefit an operation of CBM AVO analysis and an improvement of CBM evaluation.

4

Surface-based Internal Multiple Elimination in the CMP Domain − Theory and Application Strategies on Land Seismic Data

Deng S., Zhao W., Liu Z.

Acta Geophysica

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2016

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Vol. 64, no. 6

2114--2135

EN

The data-driven internal multiple elimination (IME) method based on feedback model, which includes CFP-based, surface-based and inversion-based methods, are successfully applied to marine datasets. However, these methods are computationally expensive and not always straightforward on land datasets. In this paper, we first proved that the surface-based IME method, which is the most computationally efficient method among the three methods, can be derived from the CFP theory. Then we extend it to CMP domain under the assumption of locally lateral invariance of the earth, which makes it more computationally efficient. In addition, we proposed applying a time-variant taper based on the first Fresnel zone to predict the multiples more percisely. Besides, the improved S/N ratio and dense offset distribution can be obtained by using the CMP supergather, which makes the CMP-oriented method more suitable for land data. Some practical processing strategies are proposed via case study. The effectiveness of the proposed method is demonstrated with the application to synthetic and field data.

5

Design of a Hold-off Time Control Circuit for Geiger-mode Avalanche Photodiodes

Deng S., Morrison A. P. A. P.

International Journal of Microelectronics and Computer Science

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2012

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Vol. 3, nr 2

53-59

EN

A high-resolution hold-off time control circuit for Geiger-mode avalanche photodiodes (GM-APDs) that enables linear changes to the hold-off time from several nanoseconds to microseconds is presented. The resolution of the hold-off time can be varied from nanoseconds to tens of nanoseconds with a range up to microseconds to cater for a variety of GM-APDs. This circuit allows setting of the optimal 'afterpulse-free' hold-off time for any GM-APD through digital inputs or additional signal processing circuitry. With this circuit, the APD is automatically reset following the end of the hold-off period that further simplifies the end-user's control. A layout of this circuit is designed using a conventional 0.15 μm complementary metal oxide semiconductor (CMOS) process, resulting a area of 95 μm x 55 μm which makes it suitable for use with APD arrays.

6

Prospects for correlation of the Triassic/Jurassic boundary between marine and non-marine facies using carbon-isotope stratigraphy: a case study from Xinjiang, northwest China

Hesselbo S., Deng S., Lu Y.

Volumina Jurassica

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2006

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Vol. 4, no. 1

286-287

EN

An apparently global pattern of carbon-isotope change in carbonates and organic matter across the T/J boundary has increasingly been recognized from marine sections, and may be useful as a basis for correlation. Evidence from other geological events indicates that this isotopic pattern should also have the power to resolve correlations between marine and non-marine sections where organic matter is preserved. In the present study we apply this method to the non-marine succession in the Junggar Basin, Xinjiang, northwest China. The Haojiagou Section there includes an excellent ˜700 m thick exposure of the Haojiagou Formation and lower member of the Badaowan Formation, from which fossils indicative of the T/J boundary have been described. However, different horizons have been suggested on the basis of different fossil groups. The T/J boundary has previously been placed at the lowest level in the section (at the base of Bed 25, Haojiagou Formation) on the basis of megaspores, and Bed 40, higher in the Haojiagou Formation, has been suggested to be Early Jurassic in age based on the occurrence of conchostracan taxa and the bivalve Ferganochonca. In contrast, on the basis of palynology, the T/J boundary has been placed higher in the section, at the base of Bed 45 (also the base of the Badaowan Formation), where there is an absence of pre-Jurassic index fossils such as Taeniaesporites, and occurrences of the post-Triassic index fossils, such as Cyathidites. Macrofossil plants suggests that the boundary lies between Beds 37 and 51 based on Hausmannia sp. in Bed 37, and Todites princeps and Clathopteris elegans in Bed 51 and higher. Carbon-isotope data have been obtained from both bulk sedimentary organic matter and from fossil wood fragments that were individually selected. Delta 13CWood carbon isotope values show a systematic stratigraphic trend from -21 per mil in Bed 25, to -26 per mil in Bed 52, although some samples around bed 25 also show very light isotopic values. Bulk organic isotope data show a similar overall trend, but show considerably less variance. Although the data are noisy, they suggest that the "main" negative isotope excursion of marine sections corresponds to the formational boundary and the "T/J boundary" recognized on the basis of plant macrofossils and microfossils, whilst the "initial" isotope excursion of marine sections may be expressed in wood values around beds 23-25. Depending on GSSP decisions either of these horizons may be regarded as the T/J boundary.

7

Middle Jurassic flora from Turpan-Hami Basin, Xinjiang, Northwest China

Deng S., Ping S., Lu Y.

Volumina Jurassica

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2006

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Vol. 4, no. 1

265-265

EN

A flora of 88 species belonging to 42 genera has been recorded from the Xishanyao Formation of Turpan-Hami Basin, Xinjiang, Northwestern China. The list of the species include: bryophyte - Thallites clarus Zhang et Zheng, T. sp.; lycopod - Lycopodites falcatus Lindley et Hutton; Sphenopsida - Equisetites lateralis Phillips, Equisetites sp., Neocalamites hoerensis (Schimper) Halle, N. carcinoides Harris, N. carrerei (Zeiller) Halle, Radicites sp. and Annulariopsis simpsoni (Phillips); ferns - Todites williamsoni (Brongniart) Seward, Coniopteris bella Harris, C. burejensis (Zalessky) Seward, C. hymenophylloides (Brongniart) Seward, C. murrayana (Brongniart) Harris, C. spectabilis Brick, C. tatungensis Sze, C. sp., Eboracia lobifolia (Phillips) Thomas, Clathropteris cf. obovata Oishi, Dictyophyllum sp., Cladophlebis asiatica Chow et Yeh, Cl. argutula (Heer) Fontaine, Cl. haiburnensis (L. et H.) Brongniart, Cl. hirta Moeller, Cl. fangtzuensis Sze, Cl. magnifica Brick, Cl. ulanensis Li et Wu, Cl. sp. 1, Cl. sp. 2, Cl. sp. 3, Raphaelia diamensis Seward and Sphenopteris sp.; Cycadales and Bennettitales - Pterophyllum mentougouensis Chen et Dou, P. sp., Anomozamites nilssoni (Phillips), A. major (Brongnart), A. sp., Nilssonia cf. acuminata Presl, Nilssonia sp., Nilssoniopteris pristis Harris, N. vittata (Brongniart) Florin, N. cf. uwatakoi (Oishi) Li, Williamsoniella cf. karataviensis Turiket., Williamsonia(?) sp., Taeniopteris sp. and Deltolepis sp.; Ginkgopsida - Ginkgo longifolius Harris, G. digitata (Brongniart) Heer, Ginkgoites sibiricus (Heer) Seward, G. obrutschewi Seward, G. yimaensis Zhou et Zhang, G. sp., Baiera gracilis (Benan MS) Bunbury, B. furcata (L. et H.) Braun, B. setacea Zhang, B. sp., Sphenobaiera longifolia (Pomer) Florin, Sph. setacea Zhang, Sph. sp., Eretmophyllum cf. saighanense (Seward) Seward, E. sp., Phoenicopsis angustifolia Heer, Ph. speciosa Heer, Ph. sp., Czekanowskia rigida Heer, C. setacea Heer, Vittifoliolum cf. segregatum Zhou and Ixostrobus lepidus (Heer) Harris; Coniferopsida - Pityophyllum lindstroemi Nathorst, P. longifolium (Nathorst) Moeller, P. nordenskioldi Heer, Pityocladus kobukensis Seward, P. sp., Pityostrobus sp., Elatocladus manchurica (Yokoyama) Yabe, E. sp., Schizolepis sp., Podozamites eichwaldi Schimper, P. lanceolatus (Lindley et Hutton) Braun, P. sp., Ferganiella sp., Storgaardia sp. and Elatides sp.; and some seeds - Conites sp., Carpolithus latizonus Li, C. retioformus Wu, C. strumatus Wu. The flora is chiefly composed of Filicopsida, Ginkgoposida and Cycadopsida. Among the Filicopsida, the Dicksoniaceae and Cladophlebis are the predominating groups. The former is represented by 8 species and the latter - about 10 species which are characterized by large pinnules. Ginkgopsida with 22 species are dominated by Ginko-like leaves and Phoenicopsis. Cycadopsida ranks the third position with 14 species, mostly assigned to Anomozamites, Nilssoniopteris and Nilssonia. Coniferopsida with 15 species makes up about 17% of the flora and are characterized by long or broad leaf types including Podozamites, Elatocladus and Pytyophyllum. Sphenopsida is a relative smaller group, but specimens of Neocalamites are abundant. The flora can be compared with the Middle Jurassic floras of Middle Asia, England, which indicates the age of the flora is the Middle Jurassic, possibly the Aalenian-Bajocian.

8

Flora assemblages at the Triassic/Jurassic boundary in Junggar Basin, Xinjiang Northwest China

Deng S.

Volumina Jurassica

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2006

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Vol. 4, no. 1

278-278

EN

The Upper Triassic and Lower Jurassic deposits in Junggar Basin, Xinjiang, Northwest China represent continuous succession and are divided into the Haojiagou Formation, Badaowan Formation and Sangonghe Formation (from base to the top). The Sangonghe Formation is definitely of the Early Jurassic age as based on plant, spore-pollen, conchostracans and bivalves. The ages of the Haojiagou and Badaowan formations are less clear. The Triassic/Jurassic boundary runs somewhere in the uppermost part of the Haojiagou Formation or in the Badaowan Formation as indicated by flora assemblages. Organic carbonaceous isotopic measurement suggests the position of the boundary in question at the base of the Badaowan Formation. The flora of the Haojiagou and the Badaowan Formations may be subdivided into the following assemblages. 1. Danaeopsis fecunda - Cladophlebis ichunensis assemblage. This assemblage is from the lower part of the Haojiagou Formation. It consists of about 20 species, characterized by Danaeopsis fecunda and numerous Cladophlebis. The main species include Danaeopsis fecunda Halle, Todites cf. shensiensis Pan, Cladophlebis ichunensis Sze, Cl. nebbensis (Brongn.) Nathorst, Cl. paralobifolia Sze, Sphenopteris chowkiawanensis Sze, Rireticopteris sp. and Cycadocarpidium sp. It is definitely of the Late Triassic age. 2. Neocalamites - Hausmannia assemblage. This assemblage is from the upper part of the Haojiagou Formation. It is composed of about 10 species with marked dominance of Neocalamites horerensis and Hausmannia xinjiangensis sp. nov. The assemblage is possibly of the Late Triassic age. 3. Todites princeps - Clathropteris elegans, assemblage. This assemblage is from the lower part of the Badaowan Formation, with about 15 species. Todites princes and Clathropteris elegans are dominant in the assemblage. It may be of earliest Early Jurassic age. 4. Coniopteris gaojiatianensis - Cladophlebis denticulata assemblage. This assemblage is abundant and of higher specific diversity. The main elements are: Selaginellites drepanoformis Zheng, Todites williamsoni (Brongniart) Seward, Coniopteris gaojiatianensis Zhang, Cladophlebis denticulata (Brongniart) Fontaine, Cl. gracilis Sze, Cl. hirta Moeller, Cl. cf. shansiensis Sze, Raphaelia diamensis Seward, Ginkgoites sp., Sphenobaiera sp., Czekanowskia rigida Heer, Samaropsis parvula Heer, S. rotundata Heer. It is noticeable that Coniopteris is recorded commonly. The assemblage occurs in the upper part of the Badaowan Formation and is of Early Jurassic age.

9

Cascaded Fresnel digital hologram and its application to watermarking

Deng S., Liu L., Lang H., Zhao D., Liu X.

Optica Applicata

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2006

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Vol. 36, nr 2-3

413-420

EN

A cascaded Fresnel digital hologram (CFDH) is proposed, together with its mathematical derivation. Its application to watermarking has been demonstrated by a simulation procedure, in which the watermark image to be hidden is encoded into the phase of the host image. The watermark image can be deciphered by the CFDH setup, the reconstructed image shows good quality and the error is almost close to zero. Compared with previous technique, this is a lensless architecture which minimizes the hardware requirement, and it is used for the encryption of digital image.

10

Weak sharp minima revisited Part I : basic theory

Burke J., Deng S.

Control and Cybernetics

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2002

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Vol. 31, no 3

439-469

EN

The notion of sharp minima, or strongly unique local minima, emerged in the late 1970's as an important tool in the analysis of the perturbation behavior of certain classes of optimization problems as well as in the convergence analysis of algorithms designed to solve these problems. The work of Cromme and Polyak is of particular importance in this development. In the late 1980's Ferris coined the term weak sharp minima to describe the extension of the notion of sharp minima to include the possibility of a non-unique solution set. This notion was later extensively studied by many authors. Of particular note in this regard is the paper by Burke and Ferrris which gives an extensive exposition of the notion and its impact on convex programming and convergence analysis in finite dimensions. In this paper we build on the work of Burke and Ferris. Specifically, we generalize their work to the normed linear space setting, further dissect the normal cone inclusion characterization for weak sharp minima, study the asymptotic properties of weak sharp minima in terms of associated recession functions, and give new characterizations for local weak sharp minima and boundely weak sharp minima. This paper is the first of a two part work on this subject. In Part II, we study the links between the notions of weak sharp minima, bounded linear regularity, linear regularity, metric regularity, and error bounds in convex programming. Along the way, we obtain both new results and reproduce many existing results from a fresh perspective.