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Juglans sigillata Dode is an endemic species in the southwest China, and is an important nut and woody oil tree. The shell of its fruit is hard and can be used to make various crafts. From 216 to 2019, typical stem rot symptoms of 8-year-old J. sigillata were observed in cultivated fields in a 600-ha orchard in Zigong, Sichuan province, China. At this orchard, approximately 35% of the trees have been seriously damaged over the past few years. The typical symptoms were water-soaking on the stem, rotting, wilting, and blighting, eventually leading to the death of the plant. In June, ten diseased tissues were collected and surface-sterilized by 3% NaClO and 75% alcohol. Morphological observations were made from the isolates grown on Potato dextrose agar (PDA) and incubated at 25°C for 3 to 9 days. Morphological characteristics were made on pure cultures grown on Synthetic low nutrient agar (SNA). Five isolates with similar morphology were isolated from single spores. Colonies on PDA reached 8.3 cm in diameter after 6 days at 25 °C, aerial mycelia were white to cream and wol-like, later turning violet and dark purple with age. The hyphae of the strain were colorless and septate. There were two types of conidia on SNA, microconidia and macroconidia. Microconidia (n = 50) were oval, elliptic or clavate, no septate, 2.2 to 3.8 × 7.6 to11.7 μm. Conidiophores were branched or unbranched, solitary or in groups, phialides cylindrical to flask-shaped, monophialidic and polyphialidic. Macroconidia (n = 50) were long slender with a curved apical cell and foot-like basal cell, 3 to 4 septate and 2.1 to 3.9 × 26.2 to 53.4 μm. For molecular identification, the internal transcribed spacer (ITS), β-tubulin (TUB2), translation elongation factor (TEF1) and large subunit (LSU) were amplified with the corresponding primer pairs ITS1/ITS4 (White et al. 1990), BT2A/BT2B, EF1/EF2 (O'Donnell et al. 1997), and LROR/LR5 (Rehner and Samuels 1994), respectively. BLAST search results indicated that the ITS, TUB2, TEF1, LSU sequences (GenBank acc. nos. MT791384, MT786729, MN853324, and MT705246) showed 99 to100% identity with Fusarium fujikuroi sequences at NCBI (GenBank acc. nos. MG798789, MH398245, MK604519 and KJ954504). The results were confirmed by multilocus phylogenetic analysis. Based on the morphological characteristics and molecular analysis of the isolates, the fungus was identified as F. fujikuroi (Leslie and Summerell 2006). Koch's postulates were checked under controlled conditions. Fifteen 2-year-old healthy potted J. sigillata were inoculated by pricking the epidermis of stem with a needle and applying 150 µl of a microconidial suspension (1 × 106 spores/ml) to the wounded surface with a brush. Sterilizd distilled water was used as the control. The experiment was repeated three times. All the plants were incubated at 25 ± 2°C after inoculation for daily observation of disease development. After 12 days, the inoculated plants showed the same symptoms as observed in the original diseased plants, while the control plants were asymptomatic. The fungus was re-isolated from the symptomatic stems and was completely identical to the isolates used to inoculate the plants. Thus, we confirmed that F. fujikuroi caused the stem rot of J. sigillata. To our knowledge, this is the first report of this fungus causing stem rot in J. sigillata in China. Our results can help identify stem rot disease of J. sigillata and develop control measures for the disease.

Cycas debaoensis Y. C. Zhong et C. J. Chen is an endemic species in China that is listed among China's national key preserved wild plants (Class I) (Xie et al. 2005). It is mainly distributed in south China (Guangxi, Guizhou, and other regions). In April 2017, a new leaf disease of C. debaoensis was found in Chengdu (30°35'32″ N; 104°05'11″E) in China with an incidence over 40%. Symptoms on C. debaoensis initially appeared as brown necrotic lesions on the margin or in the center of leaves. The lesions then enlarged gradually and developed into brown spots, necrotic lesions with dark brown margins. Many small and black dots were observed on necrotic lesions. Eventually, the diseased leaves withered and died. Ten samples were collected and surface-sterilized by 3% NaClO and 75% ehanol respectively for 60s and 90s, rinsed with autoclaved distilled water and then blot-dried with autoclaved paper towels. Five isolates from diseased leaves with similar morphology were isolated from single spores. Morphological characteristics were recorded from pure cultures grown on potato dextrose agar (PDA) incubated at 25°C for 3-9 days. Initially, the colonies grown on PDA were white, then, became pale gray with concentric zones and greenish black beneath. Conidia were single-celled, smooth-walled, straight, colorless, cylindrical with both ends bluntly rounded,13.0-16.5 × 4.7-5.8 μm in size (n = 100 spores). For molecular identification, the genomic DNA of the isolates was extracted using a DNeasyTM Plant Mini Kit (Qiagen). The internal transcribed spacer (ITS) (ITS1/ITS4 White et al., 1990), β-tubulin (TUB2) (BT2A/BT2B (O'Donnell et al., 1997)), actin (ACT) (ACT512F/ACT (Carbone & Kohn, 1999)), calmodulin (CAL) (CL1C/CL2C (Weir et al., 2012)), mating type protein and chitin synthase (CHS-1) (CHS-1) (CHS-9 79F/CHS-345R (Carbone & Kohn, 1999)) were amplified. BLAST results indicated that the ITS, TUB2, ACT, CAL, CHS-1 sequences (GenBank MN305712, MN605072, MT478663, MT465591 and MT478664) showed 99-100% identity with C. siamense sequences at NCBI (GenBank JF710564, MK341542, MK855094, MH351155 and MK471373). The Phylogenetic tree inferred from the combined dataesets (TEF, TUB and ACT) show that the isolate belongs to C. siamense clade with a credibility value of 99%. Two-year-old potted plants of C. debaoensis (10 plants) were used for pathogenicity test. On each plant, 5 leaves were sprayed with a conidial suspension (1 × 106 conidia/ml) on both sides of the leaves. Autoclaved distilled water was used as negative control (10 plants). Plants were kept in the greenhouse at 25 °C under 16h/8h photoperiod and 70-75% relative humidity (RH). The symptoms observed on the inoculated plants were similar to those observed in the field, while the controls remained asymptomatic. C. siamense was re-isolated from all diseased inoculated plants, and the culture and fungus characteristics were the same as the original isolate. The morphological characteristics and molecular analyses of the isolate matched the description of C. siamense (Prihastuti et al., 2009). C. siamense was previously reported infecting Citrus reticulata (Cheng et al. 2013), but this is the first report of brown leaf spot on C. debaoensis caused by C. siamense in China. This finding provides important basis for further research on the control of the disease.

Although Alkali-Surfactant-Polymer (ASP) flooding enhance oil recovery (EOR) technique has been put forward many years ago, it was not until 2014 that it is first put into industrial application in Daqing Oilfield in China. Under such low oil price, ASP flooding advance in China provides confidence for ASP flooding as a chemical EOR technology. In 2014, ASP flooding entered into industrial application stage first time in history. Crude oil production from ASP flooding in 2015 and 2016 in Daqing Oilfield was 3.5million and 4 million ton, which accounts for the 9% and 11% total oil production respectively. In 2016, another large scale ASP flooding field test in high temperature (81 °C) reservoir in central was seen staged incremental oil recovery 7.7% in central well zone. 30 ASP flooding field tests in China were reviewed to help promote wiser use of this promising technology. ASP flooding in Daqing Oilfield deserves most attention. Strong alkali (NaOH) ASP flooding (SASP) was given more emphasis than weak alkali alkali (Na2CO3) ASP flooding (WASP) in a long time in Daqing, lower interfacial tension(IFT) of surfactant and higher recovery in presence of NaOH than Na2CO3 the most important reason. Other ASP flooding field tests finished in China are all Na2CO3 based, including one using mixture of NaOH and Na2CO3. With progress in surfactant production, a recent large scale WASP field tests in Daqing was seen incremental oil recovery of near 30%, higher than most previous SASP ones, and near to the most successful SASP one. However, this most successful SASP was partly attributed to the weak alkali factor. Recent studies shows that WASP incremental oil recovery factor could be as good as SASP but with much better economic benefits. According to Daqing Oilfield review, the equipment IFT is more determinant than dynamic IFT in contribution to displacement efficiency, thus it is better to choose lower dynamic IFT when equilibrium IFT met the 10-3 orders of magnitude requirement. However, it is impossible for many surfactants to form equilibrium IFT, thus dynamic minimum IFT was chosen as criteria. For low acid value Daqing crude oil, asphaltene and resin component plays a very important role in reducing oil/water IFT, and asphaltene is believed more influential, though more work are required to answer this controversial issue. Progress in surfactant production, overcoming of scaling and produced fluid handling challenger is the foundation of ASP industrial application. Dynamic adjustment in ASP flooding is common practice in Daqing. For the compatibility between ASP and formation pore structure, especially considering emulsion and formation damage, no satisfactory standards are found yet. Further work should be on emulsification effect in ASP flooding. Mixture of cation and anion surfactants used in Henan Oilfield may be a good choice to face the high temperature challenge. Ultra-high temperature reservoir ASP flooding with organic alkali is under investigation and a field test is in schedule. It is very difficult to carry out ASP flooding in high temperature and high divalent cation reservoir and no success was seen in such kind of reservoirs in China. According to one field test, EOR routine should be selected with consideration of residual oil type to decide whether to enlarge sweep volume or/and displacement efficiency. Micellar flooding failure in Yumen Laojunmiao (YM-LJM) reservoir makes subsequent field tests choose the "small concentration large slug" technical route instead of "high concentration small slug" one like YM-LJM. ASP flooding can increase oil recovery by 30% and control the cost below 30 US dollar/bbl, thus it can be used to face low oil price challenge.

Both laboratory and oil field tests have documented that enhanced oil recovery can be obtained by performing positioning blockage technology with the lower cost and the higher strength. Modified starch gel (MSG) is the preferred gel for positioning blockage technology considering its resistance abilities on temperature, salty and shear of the graft copolymerization between starch and allyl monomer. Due to the complexity of the reaction which is fractional and its rate bases on velocity, the physicochemical characteristics of MSG are totally different from conventional gel. Based on published data, graft copolymerization reaction rate equation with velocity and concentration is established and physical process for generated copolymer adsorption is characterized, which agreed with documented experimental facts. The dynamic characteristics of injection pressure are obtained by laboratory displacement experiment, which is designed including the early water driving stage, the middle MSG driving stage and the subsequent water driving stage. The quantitative results of characteristic parameters, such as residual resistance coefficient, maximum adsorption amount and viscosity, are achieved by fitting the injection pressure curve of laboratory displacement experiment using numerical simulation technology by CMG software. The viscosity of gel is about three times higher than that of polymer. MSG system had good gelation property which is helpful to enhance the plugging ability.

The interface properties of 4H-SiC metal-oxide-semiconductor (MOS) capacitors with post-oxidation annealing (POA) in nitric oxide (NO) ambient after high temperature (1300 ℃) oxidation have been investigated using capacitance-voltage ( C - V ) measurements. The experimental results show that the interface states density can be obviously decreased by the POA in NO ambient, and further reduced with increasing POA temperature and time. In the meantime interface state density and oxidation time could be lowered at higher thermal oxidation temperature, which results in the better oxide MOS characteristics and lower production costs. POA temperature and time dependence of 4H-SiC MOS interface are also discussed in detail.