**1. Introduction**

Grain size plays a significant role in determining the strength and toughness of materials. During the welding process, austenite tends to grow thermally and the austenite grain size provides the initial condition for the subsequent phase transformation during cooling and then affects the final microstructure and resulting mechanical properties [1,2]. It is reported that increasing the austenite grain size shifts the continuous cooling transformation diagram to longer reaction time and increases the possibility of martensite formation. Martensite formation may lower the toughness [3–5]. Large austenite grain size is of particular concern during welding where the HAZ experiences rapid thermal

cycles with high peak temperature which give rise to austenite grain growth, especially in the region adjacent to the fusion zone (coarse-grained heat-affected zone, CGHAZ). Therefore, the austenite growth behavior has aroused much interest in the past several decades [6–8].

Alloying elements are of importance in affecting the austenite grain growth. Microalloying elements, like Nb, V and Ti, suppress the austenite growth as (Nb,V,Ti)(C,N) precipitates pin the austenite grain boundaries before complete dissolution at 1200 ◦C on heating [9–12]. Some elements, like B, easily segregate at grain boundaries. Thus, they reduce the austenite growth rate and result in finer grain at room temperature in CGHAZ. Ni is an austenite former element. When enriched in retained austenite in the original microstructure, it may enhance the reversed austenite nucleation site and lead to the final finer grain [13,14]. Other main elements, e.g., Mn should play a role in influencing the austenite grain growth due to either austenite former element or segregation to the grain boundaries. However, there is a lack of information about the Mn effect on austenite growth during welding.

Mn has been utilized in advanced cryogenic steels to replace Ni recently. Like Ni, Mn can enlarge the γ phase and prompt reversed austenite. Additionally, Mn enriches the reversed austenite and enhances its stability, thus improving the cryogenic toughness. In this present work, 5% Mn cryogenic steel was experimented. The following issues were investigated based on reversed austenite transformation at a high temperature of the welding thermal cycle:


Author details

ion implantation have been studied combining IPE and ac conductance spectroscopy methods on nitrogen implanted SiC/SiO2interfaces [132]. IPE reveals that nitrogen incorporates in carbon clusters at the SiC/SiO2 interface that causes a shift of the electron levels to higher binding energies. Inferring the Schottky barrier height from the IPE spectra, it has been shown that ion implantation of sulfur in the NiSi/Si barrier does not induce changes in the barrier height, but increases doping in silicon [133]. The silicide/Si barrier modification by intentional dopant

Defects generated by ionizing radiation and/or electric field, as well as the defects in undamaged devices, are considered to be spatially distributed across the SI interface and can be classified accordingly to the spatial location as the oxide-related traps and the interface traps. In respect to the latter, it is generally accepted that the interface traps are rapidly communicating with the silicon conduction or valence bands. The defects within the oxide interlayer also can exchange charge with silicon as has been revealed by the noise measurements [135]. Combining ac admittance spectroscopy and the noise measurements, it has been established that the fast interface states at the Si/SiO2 interface, likely associated with the dangling bond defects, contribute to the loss peak in conductance measurements [136]. The defect states residing in an oxide layer are responsible for 1/f noise and random telegraph noise. These trapping centers in the oxide contribute to the conductance plateau at low frequency in ac conductance spectra (cf. Figure 2 of Ref. [137]). A separable contribution of the oxide-related traps has been revealed employing measurements of subthreshold current [138] and the charge-pumping technique [139] to MOSFETs and CV measurements taken on the gate-controlled diode [140]. The latter technique is applicable for characterization of the interface traps in MOS devices composed on wide band gap semiconductors, because it allows supplying minority carriers in an amount sufficient to compensate for the low thermal generation rates of the minority carriers. An alternative method of providing minority carriers to invert a semiconductor surface is a controlled deposition of surface charges onto an insulator surface from corona discharging in air as it has been proposed in Ref. [141]. In this work, a surface charge has been deposited on SiO2 and high-k dielectrics to overcompensate the carrier leakage current in silicon MOS capacitors and enable extraction of Dit(E) profiles following the Berglund formalism. There are several advantages of the inverting semiconductor surfaces by employing noninvasive electrostatic charging of an insulator surface in a MOS structure: (i) The method does not involve fabrication of a transistor or a gate-controlled diode. (ii) The Berglund analysis can be used to reliably estimate Dit(E) over the major part of a semiconductor band gap (for Si, from 0.2 to 0.9 eV above the valence band edge) using just MOS capacitors of one type of semiconductor conductivity. (iii) The method may employ CV measurements at mid-kHz frequency range allowing investigation of samples, which experience relatively high

The sub-division of the interface trap responses into slow and fast on the basis of their characteristic time constants is important in research on the irradiation-induced damage in MOS devices. The interface state generation under irradiation or high electric field stress can involve electron-

segregation has been verified in work [134].

86 Ion Implantation - Research and Application

leakage current.

4.5. Slow interface states as a special case of study

Yanina G. Fedorenko

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Stephenson Institute for Renewable Energy and Department of Physics, School of Physical Sciences, Chadwick Building, University of Liverpool, Liverpool, UK


**Partial Root-Zone Drying and Deficit Irrigation E**ff**ect on Growth, Yield, Water Use and Quality of Greenhouse Grown Grafted Tomato**

**Branimir Urli´c 1,\*, Marko Runji´c 1, Marija Manduši´c 1, Katja Žani´c 1, Gabriela Vuletin Selak 2, Ana Mateškovi´c 1 and Gvozden Dumiˇci´c 2**

Received: 9 August 2020; Accepted: 26 August 2020; Published: 1 September 2020

**Abstract:** The tomato is an important horticultural crop, the cultivation of which is often under influence of abiotic and biotic stressors. Grafting is a technique used to alleviate these problems. Shortage of water has stimulated the introduction of new irrigation methods: deficit irrigation (DI) and partial root-zone drying (PRD). This study was conducted in two spring–summer season experiments to evaluate the effects of three irrigation regimes: full irrigation (FI), PRD and DI on vegetative growth, leaf gas-exchange parameters, yield, water-use efficiency (WUE), nutrients profile and fruit quality of grafted tomatoes. In both years, the commercial rootstocks Emperador and Maxifort were used. In the first year, the scion cultivar Clarabella was grown on one stem and in the second year the cultivar Attiya was grown on two stems. Self-grafted cultivars were grown as a control. In both experiments, higher vegetative traits (leaf area and number, height, shoot biomass) were recorded in tthe plants grafted on commercial rootstocks. The stomatal conductance and transpiration rate were higher under FI. Under DI, transpiration was lowest and photosynthetic WUE was highest. Photosynthetic rate changed between irrigation treatments depending on plant type. In both years, the total yield was highest in grafted plants as result of more and bigger fruits per plant. In the 2nd year, grafted plants under FI had higher yield compared to PRD, but not to DI, while self-grafted plants did not differ between irrigation treatments. WUE was highest in DI and PRD treatments and in grafted plants. Leaf N, P, K and Ca was highest in tthe plants grafted on Emperador and Maxifort, while more Mg was measured in self-grafted plants. More Ca and Mg were recorded in tthe plants under DI and PRD. Fruit mineral concentrations were higher in tthe plants grafted on commercial rootstocks. Total soluble solids differed between irrigation regarding plant types, while fruit total acidity was higher in Emperador and Maxifort. In conclusion, our study showed that grafted plants could be grown under DI with minor yield reduction with 30–40% less water used for irrigation. Moderate DI could be used before PRD for cultivation of grafted tomato and double stemmed plants did not show negative effect on tomato yield so it can be used as standard under reduced irrigation.

**Keywords:** reduced irrigation; rootstocks; yield traits; leaf gas exchange