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| 1 | Optimization of Agrobacterium tumefaciens-Mediated Transformation Systems in Tea Plant(Camellia sinensis)显示文摘In this study, an efficient plant regeneration protocol in vitro and transformation by Agrobacterium-mediated method of Camellia sinensis was achieved, which would lay the foundation for genetic improvement of tea plant by genetic engineering technology. The cotyledon callus of C.sinensis were used as the receptors for transformation by Agrobacterium tumefaciens EHA105 containing PS1aG-3. Some factors which affected the result of Agrobacterium-mediated transformation of C. sinensis were studied on the basis of GUS transient expression system. The optimum system of Agrobacterium-mediated transformation was that the cotyledon callus were pre-cultured for 3 d, and then infected by EHA105 for 15 min followed by 3 d co-culture in the dark on the YEB medium containing 150 μmol·L^(-1) acetosyringone(AS). The transient expression rate of GUS gene was 62.6%. After being delayed selective culture for 3 d, infected callus were transferred into the differentiation medium and the root induction medium both of which were supplemented with 100 mg·L^(-1) spectinomycin, and then resistant seedlings of C. sinensis were obtained. The conversion rate was 3.6%. | LV Qianru CHEN Changsong XU Yijuan HU Shunkai WANG Le SUN Kang CHEN Xuan LI Xinghui | 2017 | Horticultural Plant Journal2017，3，3： | 9 |
| 2 | Effect of particle type on the shear behaviour of granular materials显示文摘In discrete element method(DEM)simulations,multi-sphere(MS)clumped and convex particles are two main particle models that are used to study the mechanical behaviours of granular materials.Of interest is the evaluation of the effect of multiple contacts between clumped particles or single contacts between convex particles on the mechanical behaviours of granular materials.In this context,a series of drained triaxial compression tests were conducted on convex true(CT)ellipsoids and MS ellipsoids with aspect ratios(ARs)ranging from 1.0-2.0.The microscale results indicate that at a given AR,the critical friction angleφ_(c)changes with the particle type,whereas the peak friction angleφ_(p)is nearly independent of the particle type.The anisotropic analysis provides underlying mechanisms of the shear strength evolution from two perspectives.First,the anisotropies of granular materials are essential to shear strength as the deviatoric(q)-to-effective mean(p′)stress ratio can be expressed as the sum of the anisotropies,i.e.,q/p'≈0.4a_(c)+0.4a_(n)+0.6a_(t),where ac,an and at are the normal contact anisotropy,normal contact force anisotropy and tangential contact force anisotropy,respectively.For all samples,a_(c)and a_(n)underpin the shear strength and are influenced by the particle type.The similarφ_(p)displayed by the CT and MS ellipsoids does not translate to similar a_(n)and a_(c)but similar a_(c)+a_(n)for the two particle types.In addition,owing to their larger a_(c)+a_(n),the CT ellipsoids have a higherφ_(c)than the MS ellipsoids.Second,there is a satisfactory linear relationship between q/p'and ac within strong and non-sliding(sn)contacts a_(c)^(sn)(i.e.,q/p′=ka_(c)^(sn)),where k is the fitting parameter.Accordingly,in the peak state,the subtle difference in shear strength is attributed to the greater acsn in the CT ellipsoids than in the MS ellipsoids that is counteracted by the smaller k.However,in the critical state,the greater difference in a_(c)^(sn)between the CT and MS ellipsoids is partially offset by the smaller difference in k,causing a higherφ_(c)in the CT ellipsoids than in the MS ellipsoids. | Shunkai Liu Zhihong Nie Wei Hu Jian Gong Peng Lei | 2021 | Particuology2021，19，3： | 1 |
| 3 | Effect of local non-convexity on the critical shear strength of granular materials determined via the discrete element method显示文摘Multi-sphere clumps are commonly used to simulate non-spherical particles in discrete element method simulations.It is of interest whether the degree of local non-convexity λ affects the mechanical behaviour of granular materials with the same non-convexity η.A series of discrete-element-method biaxial shear tests are conducted on rough particle packings with rη=0.075 and different λ values(ranging from 0.134 to 0.770).The microscale results show that the contact type changes with an increase in λ.However,the critical strength is independent of λ.The evaluation of the contributions of different contact types to the critical shear strength and a detailed analysis of the anisotropies help clarify the microscopic mechanisms that result in the independence of the critical shear strength from λ. | Zhihong Nie Shunkai Liu Wei Hu Jian Gong | 2020 | Particuology2020，18，5： | 1 |
| 4 | Influence of Bayer Red Mud on the Operational and Mechanical Characteristics of Composite Cement Mortar显示文摘The aim of this study is to enhance the value and utilization of red mud generated in the Bayer process by preparing composite cement mortars.The effects of two different types of Bayer red mud with varying physical and chemical characteristics on the fluidity,mechanical strength,mineral composition,and microstructure of the composite cement mortar were systematically evaluated.The results showed that the optimal addition of red mud A was 10 wt%,while it was 20 wt% for red mud B.The mechanical properties of the composite cement mortar met the standards for P·O42.5 cement.Furthermore,the composite mortar with the addition of red mud B showed higher flexural and compressive strengths compared to the composite mortar with red mud A.This improvement is attributed to the smaller particle size of red mud B,which filled the micro-pores and increased the compactness of the cement stone,as well as its higher content of Na_(2)O,K_(2)O,and other free alkalis,which resulted in more obvious alkali activation,accelerating the hydration of the active minerals in the slurry. | Cheng Hu Weiheng Xiang Ping Chen Yi Yang Libo Zhou Jiufang Jiang Shunkai Li Yang Ming Qing Li | 2023 | Journal of Renewable Materials2023，11，11： | 0 |
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