鸭种蛋质量和蛋形指数对孵化效果的影响

【目的】研究鸭入孵蛋质量与蛋形指数对孵化过程中种蛋质量、孵化成绩及雏鸭初生体质量的影响。【方法】将同一天收集的黑鹜鸭(H)、建昌鸭(J)和农华肉鸭P系(P)种蛋测量其入孵蛋质量、长径和短径,计算蛋形指数。将种蛋分别按入孵蛋质量和蛋形指数分为3组,进行同批变温孵化,从孵化第7天起每3d照蛋1次,称量并记录种蛋质量,剔除无精蛋和死胚蛋,从孵化第26天起每天检查出雏情况,记录雏鸭初生体质量。计算入孵蛋孵化率、受精蛋孵化率、孵化期间种蛋质量损失量和质量损失率,分析鸭入孵蛋质量和蛋形指数对孵化效果的影响。【结果】3个品种不同入孵蛋质量和蛋形指数的种蛋质量损失量和质量损失率无显著差异,且变化趋势相同。入孵蛋质量分组方面,黑鹜鸭1组(质量<64.84g/枚)、建昌鸭1组(质量<76.94g/枚)和农华肉鸭P系1组(质量<88.03g/枚)的受精蛋孵化率最高,黑鹜鸭2组(质量64.84~76.28g/枚)、建昌鸭1组(质量<76.94g/枚)和农华肉鸭P系1组(质量<88.03g/枚)的入孵蛋孵化率最高;蛋形指数分组方面,黑鹜鸭3组(>1.42)、建昌鸭1组(<1.30)和农华肉鸭P系3组(>1.39)的受精蛋孵化率和入孵蛋孵化率均最高。各品种雏鸭初生体质量与入孵蛋质量呈显著正相关(P<0.05),与蛋形指数无明显相关性(P>0.05)。【结论】孵化过程中鸭种蛋的质量损失量和质量损失率与入孵蛋质量和蛋形指数无关,不同鸭品种的最佳入孵蛋质量与蛋形指数范围不同;雏鸭初生体质量随入孵蛋质量的增大而增大,但蛋形指数对其无显著影响。

Antisepsis and Fresh-keeping Effects of Natamycin Coating Compounds Treatment on Red Global Grape

The aim was to research fresh-keeping effects of natamycin on cold-pre- served grape. Red globe grapes were processed with compound coating liquid of chitosan with mass fraction at 1% and natamycin with mass fractions at 0.20% （T1）, 0.40% （T2） and 0.60% （T3）, respectively. Grapes processed with water （CK3） and 1% chitosan （CK2） were taken as control groups. Rotten rate, seed shattering rate, mass loss rate, respiratory intensity and related physiological quality in test and control groups were compared. The results indicated that respiratory intensity, mass loss rate, rotten rate and seed shattering rate in CK1 were all higher than those in CK2. In addition, T1, T2 and T3 were lower in the indices than CK1 and CK2, but still kept at a high level in fruit hardness. Furthermore, mass fractions of Vc and titratable acid declined more slowly in T1, T2 and T3, compared with CK1 and CK2. Natamycin better preserved grapes and prolonged storage period. In general, natamycin with mass fraction at 0.4% proved best in fresh-keeping.

Predictive factors for body weight loss and its impact on quality of life following gastrectomy

To determine the predictive factors and impact of body weight loss on postgastrectomy quality of life (QOL). METHODSWe applied the newly developed integrated questionnaire postgastrectomy syndrome assessment scale-45, which consists of 45 items including those from the Short Form-8 and Gastrointestinal Symptom Rating Scale instruments, in addition to 22 newly selected items. Between July 2009 and December 2010, completed questionnaires were received from 2520 patients with curative resection at 1 year or more after having undergone one of six types of gastrectomy for Stage I gastric cancer at one of 52 participating institutions. Of those, we analyzed 1777 eligible questionnaires from patients who underwent total gastrectomy with Roux-en-Y procedure (TGRY) or distal gastrectomy with Billroth-I (DGBI) or Roux-en-Y (DGRY) procedures. RESULTSA total of 393, 475 and 909 patients underwent TGRY, DGRY, and DGBI, respectively. The mean age of patients was 62.1 ± 9.2 years. The mean time interval between surgery and retrieval of the questionnaires was 37.0 ± 26.8 mo. On multiple regression analysis, higher preoperative body mass index, total gastrectomy, and female sex, in that order, were independent predictors of greater body weight loss after gastrectomy. There was a significant difference in the degree of weight loss (P < 0.001) among groups stratified according to preoperative body mass index (< 18.5, 18.5-25 and > 25 kg/m2). Multiple linear regression analysis identified lower postoperative body mass index, rather than greater body weight loss postoperatively, as a certain factor for worse QOL (P < 0.0001) after gastrectomy, but the influence of both such factors on QOL was relatively small (R2, 0.028-0.080). CONCLUSIONWhile it is certainly important to maintain adequate body weight after gastrectomy, the impact of body weight loss on QOL is unexpectedly small.

Effect of carbonation-drying-wetting on durability of coral aggregate seawater concrete

Based on the drying-wetting cycles experiment and the carbonation-drying-wetting cycles experiment for coral aggregate seawater concrete(CASC)with different strength grades,the effects of carbonation-drying-wetting on the durability of CASC are studied with the surface state,mass loss rate,relative dynamic elastic modulus,ultrasonic wave velocity and cube compressive strength as indices.Results show that the mass loss rate of CASC increases gradually with the increase in cycle times in the drying-wetting and carbonation-drying-wetting cycles.The mass loss rate increases relatively slowly at the initial stage but it increases remarkably after 10 cycles.The relative dynamic elastic modulus and ultrasonic wave velocity decrease gradually with the increase in cycle times.After 6 cycles,the decrease rate of the relative dynamic elastic modulus and ultrasonic wave velocity of CASC tends to be flat and the surface is slightly damaged.Compared with the initial 28 d cube compressive strength,the cube compressive strength of CASC decreases by 8.8%to 11.0%.Drying-wetting cycles and carbonation can accelerate seawater erosion on CASC,and drying-wetting cycles result in salting-out and accelerate the destruction of concrete.Therefore,the carbonation-drying-wetting accelerates the destruction of CASC.

Preparation and Characterization of TiO_2/Expanded Graphite

In order to obtain anatase TiO2/expanded graphite with high expansion volume, titania gel was introduced to expandable graphite surface by sol-gel process, and then the composite was expanded and calcined at high tempera- ture. The samples were analysed by using scanning electron microscope （SEM）, X-ray diffraction（XRD）, energy disperse spectroscopy （EDS）, and differential scanning calorimetry （DSC）. The optimal conditions for preparation are as follows： the molar ratio of tetrabutyl orthotitanate to triethanolamine is 1 ： 0.4, and the calcination and expansion temperature is in the range of 650--750 ~C. Under such conditions, the expansion volume of composites could reach 98 mE/g, and the mass loss ratio is less than 5%. The analysis shows that lower temperature and smaller particle size of graphite are helpful to the formation of anatase-type of TiO2, but larger particle size will lead to lower mass loss ratio, and higher temperature and larger particle size will lead to higher expansion volume.

Synthesis of biodegradable Mg-Zn alloy by mechanical alloying: Statistical prediction of elastic modulus and mass loss using fractional factorial design

Biodegradable Mg-Zn alloy was synthesized using mechanical alloying where a statistical model was developed using fractional factorial design to predict elastic modulus and mass loss of the bulk alloy.The effects of mechanical alloying parameters(i.e.,milling time,milling speed,ball-to-powder mass ratio and Zn content)and their interactions were investigated involving 4 numerical factors with 2 replicates,thus 16 runs of two-level fractional factorial design.Results of analysis of variance(ANOVA),regression analysis and R2 test indicated good accuracy of the model.The statistical model determined that the elastic modulus of biodegradable Mg-Zn alloy was between 40.18 and 47.88 GPa,which was improved and resembled that of natural bone(30-57 GPa).Corrosion resistance(mass loss of pure Mg,33.74 mg)was enhanced with addition of 3%-10%Zn(between 9.32 and 15.38 mg).The most significant independent variable was Zn content,and only the interaction of milling time and ball-to-powder mass ratio was significant as P-value was less than 0.05.Interestingly,mechanical properties(represented by elastic modulus)and corrosion resistance(represented by mass loss)of biodegradable Mg-Zn alloy can be statistically predicted according to the developed models.

热固性树脂浸渍纸高压装饰层积板(HPL)表面耐磨方法国内外标准比较分析

对比分析中国、美国、欧盟及国际标准化组织(ISO)关于HPL检测标准中表面耐磨性能的检测差异,详细分析了表面耐磨砂纸平衡条件、校准、试件平衡条件、锌板质量损失量、试验设备及最终计算结果表示的差异;结果和建议如下:(1)国标中产品标准中的方法部分经常引用方法标准,方法标准修订后产品标准在引用过程中存在条款不清的问题;(2)各国标准中均未提到实验室环境条件,应规定耐磨试验机实验室的温、湿度,从而保证试验条件一致;(3)由于对最初磨损点和最终磨损点的判定人为因素很大,建设在国标修订过程中,我们可以借鉴美标和欧标给出示意图,以方便试验人员判定,从而减少人为因素对实验结果的影响。为HPL产品提供贸易指导。

Trend of mass change in the Antarctic ice sheet recovered from the GRACE temporal gravity field

It is important to quantify mass variations in the Antarctic ice sheet hybrid filtering scheme employing a combination of the decorrelated to study the global sea-level rise and climate change. A filter P3M6 and 300 km Fan filter was used, and the sur- face mass variations over the Antarctic are recovered from GRACE CSR RL04 monthly gravity field models from August 2002 to June 2010. After deduction of leakage errors using the GLDAS hydrological model and postglacial rebound effects using the glacial isostatic adjustment model IJ05, the variations in the ice sheet mass are obtained. The results reveal that the rate of melting of the Antarctic ice sheet is 80.0 Gt/a and increasing and contributes 0.22 mm/a to the global sea-level rise; the mass loss rate is 78.3 Gt/a in the West Antarctic and 1.6 Gt/a in the East Antarctic. The average mass loss rate increases from 39.3 Gt/a for the period 2002-2005 to 104.2 Gt/a for the period 2006-2010, and its corresponding contribution to the global sea-level rise increases from 0.11 to 0.29 mm/a, which indicates accelerated ice mass loss over the Antarctic since 2006. Moreover, the mass accumulation rates for Enderby Land and Wilkes Land along the coast of East Antarctica decrease for the period 2006-2008 but increase evidently after 2009.

Three-phase 2D model of long-rod penetrating semi-infinite metal targets considering variation in nose shape

The nose shape effect on long-rod penetration was investigated by establishing numerical 2D models with different original nose shapes.The variations in nose shapes and the mass erosion rate of the rods in the transient phase,primary penetration phase,and secondary penetration phase were adequately analyzed by two dimensionless parameters,i.e.,the nose shape factor N* and the diameter ratio of the rod nose and shank n.In general,N*,η and the mass erosion rate of the rod vary distinctly in different phases,i.e.,unsteady in the initial transient and the secondary penetration phases,and quasi-steady in the primary penetration phase.Furthermore,a relationship between the mass erosion of the rod and the variation in the nose shape was established.A three-phase 2D model of long-rod penetration was further constructed by considering the variations in nose shape.This research may provide a reference to improve the theoretical model of long-rod penetration.

A mass abrasion model with the melting and cutting mechanisms during high-speed projectile penetration into concrete slabs

In this study,ogive-nose projectile penetration into concrete slabs was tested at initial projectile impact velocities ranging from 1325.0 m/s to 1425.0 m/s.The depth of penetration and mass loss of the projectiles were measured,and the residual projectiles were recovered after the penetration tests.Scanning electron microscopy and metallographic microscopy of the microstructures were performed on various sections and outer surfaces of the projectiles taken from different locations of the residual projectiles,to analyze the intrinsic mechanisms of mass abrasion.The analysis results reveal that,during high-speed projectile penetration,projectile abrasion is caused by multiple mechanisms.Based on the cavity expansion theory,a projectile penetration model was established by considering the two main mass loss mechanisms observed in the microscopic tests.The theoretical predictions of the penetration depth,mass loss rate,and change of projectile head are consistent with the experimental results obtained both in this study and previous research.