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Effects of irrigation and weed-control methods on growth of weed and rice

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International Journal of Agricultural and Biological Engineering 2014年第5期7卷 22-33页

作者： jacob Jeremiah Towa Guo Xiangping Key Laboratory of High-Effective Irrigation and Drainage and Agricultural Water and Soil Environment in Southern China Ministry of EducationHohai UniversityNanjing 210098China Irrigation and Technical Services Division Ministry of AgricultureFood Security and CooperativeDar es Salaama9192Tanzania

A field experiment was conducted to study the effects of weeds control methods and an irrigation model on rice growth as well as water consumption and weed quantity in the paddy *** conventional paddy rice production,one of the most important irrigated crops,a significant amount of irrigation water is lost due to percolation and evaporation.A new irrigation model called the Rain-Catching and Controlled Irrigation(RCCI)model has been developed as a viable water-saving technology in the production of paddy *** this study the performance of the RCCI model has been analyzed under mulching,hand weeding and weedy conditions in Jiangsu Province of *** experiment was laid out in Randomized Complete Block Design(RCBD)with three replications and nine *** three replicates consisted of three water management regimes:high dry high flooding(HD-HF),high dry low flooding(HD-LF),and shallow and frequent irrigation(SF)water *** RCCI model was adopted in HD-HF and HD-LF while Flooding Irrigation(CFI)was adopted in SF as a *** nine treatments were equally divided under mulching,hand weeding and weedy *** lowest and maximum irrigation water delivery was 244.86 mm in mulching and 429.22 mm in hand weeding,respectively at *** the lowest and maximum irrigation water delivery was 300.1 mm in the mulching field and 680.72 mm under hand weeding,respectively at *** Nanjing 44 rice variety was *** was observed that weed density and dry weight were significantly influenced by the amount of irrigation water in all the mulching,hand weeding and weedy *** yield and the number of irrigations,the RCCI model produced better results than *** under RCCI was an effective method to control weeds and reduce labor *** addition,mulching decreases the use of herbicides and the risk of *** the other hand,mulching could improve yield and save water.

关键词： irrigation weed control mulching hand weeding RCCI weed population agronomy traits paddy rice

Optical and electrical properties and phonon drag effect in low temperature TEP measurements of AgSbSe_2 thin films

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Journal of Semiconductors 2014年第5期35卷 1-6页

作者： T Namitha Asokan K S Urmila Rajani jacob Rachel Reena Philip G S Okram v Ganesan B Pradeep Solid State Physics Laboratory Department of Physics Cochin University of Science and Technology Thin Film Research Lab Department of Physics Union Christian College UGC-DAE Consortium for Scientific Research

Polycrystalline thin films of silver antimony selenide have been deposited using a reactive evaporation technique onto an ultrasonically cleaned glass substrate at a vacuum of 10-5 torr. The preparative parameters, like substrate temperature and incident fluxes, have been properly controlled in order to get stoichiometric, good quality and reproducible thin film samples. The samples are characterized by XRD, SEM, AFM and a Uv-vis-NIR spectrophotometer. The prepared sample is found to be polycrystalline in nature. From the XRD pattern, the average particle size and lattice constant are calculated. The dislocation density, strain and number of crystallites per unit area are evaluated using the average particle size. The dependence of the electrical conductivity on the temperature has also been studied and the prepared AgSbSe2 samples are semiconducting in nature. The AgSbSe2 thin films exhibited an indirect allowed optical transition with a band gap of 0.64 ev. The compound exhibits promising thermoelectric properties, a large Seebeck coefficient of 30 mv/K at 48 K due to strong phonon electron interaction. It shows a strong temperature dependence on thermoelectric properties, including the inversion of a dominant carrier type from p to n over a low temperature range 9-300 K, which is explained on the basis of a phonon drag effect.

关键词： silver antimony selenide reactive evaporation thermoelectric power phonon drag effect

Experimental and finite element analysis on determining the fatigue life of pb-free solder joint(Sn-0.5Cu-3Bi-1Ag)used in electronic packages under harmonic loads

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International Journal of Modeling, Simulation, and Scientific Computing 2020年第3期11卷 60-67页

作者： Jayesh S jacob Elias Department of Mechanical Engineering School of Engineering Cochin University of Science and Technology KochiKerala-682022India

Electronic packages that are used these days are exposed to different types of vibration loadings in their usage *** vibration exposure can be categorized as harmonic and random *** reliability assessment of modern electronic systems is considered,vibration loading has an important role to *** of the biggest challenges facing today is the accurate and rapid assessment of fatigue life under the vibration *** solder joints were made of lead-tin *** to many environment legislations and rules,lead is prohibited as an ingredient in the solder *** reason for the prohibition of the usage of the lead is that it poisons the *** this study,Sn-0.5Cu-3Bi-1Ag is used as the lead-free solder *** life prediction of electronic package containing SAC405 is conducted with the aid of vibration testing and Finite element analysis under harmonic vibration loading.A specially designed Plastic Ball Grid Array Package(PBGA)component is mounted on Printed Circuit Board(PCB).It is taken as a test vehicle for the vibration *** test vehicle is excited by a sinusoidal *** frequency of this excitation equals the fundamental frequency of the test vehicle and it is continued till the component *** the solder balls are very small for direct measurement,Finite Element analysis(FEA)is used for noting down the *** stress versus failures cycles(S-N)curve is made by relating both the stresses on the solder balls obtained and the number of failure cycles from vibration *** fatigue life of the component can be estimated from the generated S-N *** is analyzed that the methodology is effective in predicting the component’s ***,the reliability of electronic package can be improved.

关键词： PCB lead free solder joint FEA PBGA S-N curve

A molecular dynamics study of laser-excited gold

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Matter and Radiation at Extremes 2022年第3期7卷 20-30页

作者： jacob M.Molina T.G.White University of Nevada RenoNevada 89557USA

The structural evolution of laser-excited systems of gold has previously been measured through ultrafast Mev electron ***,there has been a long-standing inability of atomistic simulations to provide a consistent picture of the melting process,leading to large discrepancies between the predicted threshold energy density for complete melting,as well as the transition between heterogeneous and homogeneous *** make use of two-temperature classical molecular dynamics simulations utilizing three highly successful interatomic potentials and reproduce electron diffraction data presented by Mo et al.[Science 360,1451–1455(2018)].We recreate the experimental electron diffraction data,employing both a constant and temperature-dependent electron–ion equilibration *** all cases,we are able to match time-resolved electron diffraction data,and find consistency between atomistic simulations and experiments,only by allowing laser energy to be transported away from the interaction *** additional energy-loss pathway,which scales strongly with laser fluence,we attribute to hot electrons leaving the target on a timescale commensurate with melting。

关键词： diffraction. excited dynamics

An Iterative Pose Estimation Algorithm Based on Epipolar Geometry With Application to Multi-Target Tracking

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IEEE/CAA Journal of Automatica Sinica 2020年第4期7卷 942-953页

作者： jacob H.White Randal W.Beard the Brigham Young University ProvoUtah 84058 USA

This paper introduces a new algorithm for estimating the relative pose of a moving camera using consecutive frames of a video sequence. State-of-the-art algorithms for calculating the relative pose between two images use matching features to estimate the essential matrix. The essential matrix is then decomposed into the relative rotation and normalized translation between frames. To be robust to noise and feature match outliers, these methods generate a large number of essential matrix hypotheses from randomly selected minimal subsets of feature pairs, and then score these hypotheses on all feature pairs. Alternatively, the algorithm introduced in this paper calculates relative pose hypotheses by directly optimizing the rotation and normalized translation between frames, rather than calculating the essential matrix and then performing the decomposition. The resulting algorithm improves computation time by an order of magnitude. If an inertial measurement unit(IMU) is available, it is used to seed the optimizer, and in addition, we reuse the best hypothesis at each iteration to seed the optimizer thereby reducing the number of relative pose hypotheses that must be generated and scored. These advantages greatly speed up performance and enable the algorithm to run in real-time on low cost embedded hardware. We show application of our algorithm to visual multi-target tracking(MTT) in the presence of parallax and demonstrate its real-time performance on a 640 × 480 video sequence captured on a UAv. video results are available at https://***/Hh K-p2 h XNn U.

关键词： Aerial robotics epipolar geometry multi-target tracking pose estimation unmanned aircraft systems vision-based flight

A review of late-stage tungsten fuzz growth

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Tungsten 2022年第3期4卷 184-193页

作者： jacob A.R.Wright Department of Materials Science and Metallurgy University of CambridgeCambridgeCB30FSUK

Tungsten will be used as the plasma-facing divertor material in the International Thermonuclear Experimental Reactor(ITER)fusion *** high temperatures and high ion fluxes,a‘fuzz’nanostructure forms on the tungsten surface with dramatically different properties and could contaminate the *** simulations and experimental observations have provided understanding of the initial fuzz formation process,there is debate over whether tungsten or helium migration is rate-limiting during late-stage growth,and the mechanisms by which tungsten and helium migrations ***,the proposed mechanisms are considered in *** is concluded that tungsten migration occurs by adatom diffusion along the fuzz *** helium migration through the porous fuzz to the tungsten bulk is also required for fuzz growth,for continued bubble growth and *** likely migrates due to ballistic penetration,although diffusion may *** is difficult to determine the limiting process,which may switch from helium penetration to tungsten adatom diffusion above a threshold *** for further research to clarify the mechanisms are then considered.A greater understanding of the fuzz formation mechanism is key to the successful design of plasma-facing tungsten components,and may have applications in forming porous tungsten catalysts.

关键词： Tungsten Tungsten fuzz Plasma-material interactions Fusion reactors

Perforated appendicitis masquerading as acute pancreatitis in a morbidly obese patient

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World Journal of Gastroenterology 2008年第11期14卷 1795-1796页

作者： Michael J Forster jacob A Akoh Department of Surgery Plymouth Hospitals NHS Trust PlymouthPL6 8DHUnited Kingdom

Diagnosis and treatment of common conditions in morbidly obese patients still pose a challenge to physicians and *** too much reliance is put on investigations that can lead to a *** case demonstrates an obese woman admitted under the medical team with a presumed diagnosis of pneumonia, who was later found to have an acute abdomen and raised amylase,which led to an assumed diagnosis of *** died within 24 h of admission and post mortem confirmed the cause of death as systemic sepsis due to perforated appendicitis,with no evidence of *** elevated serum amylase level may occur in non-pancreatitic acute abdomen.

关键词： Morbid obesity Perforated appendicitis Pneumonia Serum amylase

Optimal Sampling and Assay for Estimating Soil Organic Carbon

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Open Journal of Soil Science 2021年第2期11卷 93-121页

作者： jacob v. Spertus Department of Statistics University of California Berkeley USA

The world needs around 150 Pg of negative carbon emissions to mitigate climate change. Global soils may provide a stable, sizeable reservoir to help achieve this goal by sequestering atmospheric carbon dioxide as soil organic carbon (SOC). In turn, SOC can support healthy soils and provide a multitude of ecosystem benefits. To support SOC sequestration, researchers and policy makers must be able to precisely measure the amount of SOC in a given plot of land. SOC measurement is typically accomplished by taking soil cores selected at random from the plot under study, mixing (compositing) some of them together, and analyzing (assaying) the composited samples in a laboratory. Compositing reduces assay costs, which can be substantial. Taking samples is also costly. Given uncertainties and costs in both sampling and assay along with a desired estimation precision, there is an optimal composite size that will minimize the budget required to achieve that precision. Conversely, given a fixed budget, there is a composite size that minimizes uncertainty. In this paper, we describe and formalize sampling and assay for SOC and derive the optima for three commonly used assay methods: dry combustion in an elemental analyzer, loss-on-ignition, and mid-infrared spectroscopy. We demonstrate the utility of this approach using data from a soil survey conducted in California. We give recommendations for practice and provide software to implement our framework.

关键词： Soil Organic Carbon Compositing Carbon Sequestration Sampling Design Measurement Error Statistics

Rejection of Permacol~ mesh used in abdominal wall repair:A case report

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World Journal of Gastroenterology 2009年第34期15卷 4331-4333页

作者： Franchesca T Wotton jacob A Akoh Surgery & Renal Services Directorate Plymouth Hospitals NHS TrustDerriford Hospital

Permacol mesh has shown promise when used in abdominal wall repair,especially in the presence of a contaminated surgical *** biomaterial,derived from porcine dermis collagen,has proposed advantages over synthetic materials due to increased biocompatibility and reduced foreign body reaction within human ***,we present a case report describing a patient who displayed rejection to a Permacol mesh when used in the repair of abdominal wound dehiscence following an emergency *** of the English language literature using PubMed and Medline, showed only two previously published cases of explantation of Permacoldue to sepsis or wound breakdown. The authors believe this is the first case of severe foreign body reaction leading to rejection of Permacol.Both animal and human studies show conflicting evidence of *** are several reports of successful use of Permacolto repair complex incisional herniae or abdominal walls in the presence of significant *** appears from the literature that Permacolis a promising material,but as we have demonstrated,it has the potential to evoke a foreign body reaction and rejection in certain subjects.

关键词： Abdominal wound closure Permacol rejection Foreign body reaction Biocompatibility